Thermal printhead and method of manufacturing a thermal printhead

Abstract

A thermal printhead includes a semiconductor substrate having a main face and a back face spaced apart from each other in a thickness direction, and formed with a first through portion passing through from the main face to the back face; a resistive layer including a plurality of heat generating portions arranged in a main scanning direction, and formed on the main face; a first electrode formed on the back face; a wiring layer formed on the resistive layer and in conduction with the plurality of heat generating portions; and a first through wiring housed in the first through portion. The wiring layer includes a common wiring on a first side in a sub scanning direction with respect to the plurality of heat generating portions. The first through wiring is connected to the common wiring and the first electrode.

Description

Technical Field

[0001] This invention relates to thermal printheads. Furthermore, this invention also relates to a method for manufacturing a thermal printhead. Background Technology

[0002] Patent Documents 1 and 2 disclose examples of existing thermal printheads. The thermal printhead disclosed in Patent Document 1 has a plurality of heating elements formed on a substrate and arranged along the main scanning direction. These heating elements are composed of a resistive layer formed on the substrate and a wiring layer partially overlapping the resistive layer. Each heating element is a portion of the resistive layer exposed from the wiring layer. When current flows to the wiring layer under control, one or more selected heating elements heat up.

[0003] In the thermal printhead described in Patent Document 1, the substrate material is silicon. The resistive layer and wiring layer are formed using semiconductor processes. The wiring layer includes common wiring and multiple individual wirings. On the substrate, the common wiring and multiple individual wirings are arranged on both sides of the sub-scanning direction of multiple heating elements. Here, to improve print quality, sometimes measures are taken to increase the number of multiple individual wirings while simultaneously increasing the number of multiple heating elements and reducing the width (length in the main scanning direction) of each of the multiple heating elements. This allows for more precise printing on the recording medium. However, in this case, there is insufficient space on the substrate for arranging the common wirings. When this space is insufficient, the substrate needs to be larger. Since increasing the substrate size leads to a deterioration in the manufacturing efficiency of the thermal printhead, this aspect needs to be improved. Furthermore, regarding the thermal printhead described in Patent Document 2, depending on the application, it is desirable to achieve a more miniaturized design.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2017-7203.

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-166824. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In view of the above, one of the problems to be solved by the first aspect of the present invention is to provide a thermal printhead and a method thereof that enable more precise printing without increasing the size of the substrate.

[0010] Technical means for solving problems

[0011] According to one embodiment of a first aspect of the present invention, a thermal printhead is provided. The thermal printhead includes: a semiconductor substrate having a main surface and a back surface spaced apart from each other in a thickness direction, and forming a first through portion extending from the main surface to the back surface; a resistive layer including a plurality of heating elements arranged in a main scanning direction and formed on the main surface; a first electrode formed on the back surface; a wiring layer formed on the resistive layer and communicating with the plurality of heating elements; and a first through wiring housed in the first through portion. The wiring layer includes a common wiring located on a first side in a sub-scanning direction relative to the plurality of heating elements. The first through wiring is connected to the common wiring and the first electrode.

[0012] Preferably, the thermal printhead further comprises a plurality of second electrodes and a plurality of second through-wires formed on the back surface. The wiring layer includes a plurality of independent wires located on a second side relative to the plurality of heating elements in the sub-scanning direction. A plurality of second through-sections are formed on the semiconductor substrate, extending from the main surface to the back surface and located on the opposite side of the first through-section relative to the plurality of heating elements in the sub-scanning direction. Each of the plurality of second through-wires is independently housed within one of the plurality of second through-sections. Each of the plurality of second through-wires is connected to any one of the plurality of independent wires and any one of the plurality of second electrodes.

[0013] Preferably, the main surface includes a base surface and a convex surface protruding from the base surface in the thickness direction, the convex surface extending along the main scanning direction, and the plurality of heating elements formed on the convex surface.

[0014] Preferably, the convex surface includes: a top surface parallel to the base surface; and a pair of inclined surfaces connected to the top surface and the base surface and located at a position away from each other in the sub-scanning direction, wherein the plurality of heating elements are formed on the top surface.

[0015] Preferably, a portion of the aforementioned common wiring and a portion of each of the aforementioned plurality of independent wirings are formed on either of the aforementioned pair of inclined surfaces.

[0016] Preferably, the pair of inclined surfaces are inclined relative to the base surface in such a way that they move closer to each other as they move from the base surface to the top surface.

[0017] Preferably, each of the pair of inclined surfaces includes: a first region connected to the base surface; and a second region connected to the top surface and the first region, wherein the inclination angle of the second region relative to the base surface is smaller than the inclination angle of the first region relative to the base surface.

[0018] Preferably, the semiconductor substrate comprises a single crystal material of silicon.

[0019] Preferably, the thermal printhead also has a first insulating layer covering the main surface, and the resistive layer is in contact with the first insulating layer.

[0020] Preferably, the semiconductor substrate has a first inner peripheral surface and a plurality of second inner peripheral surfaces, the first inner peripheral surface being connected to the main surface and the back surface and defining the first through portion, the second inner peripheral surface being connected to the main surface and the back surface and defining each of the plurality of second through portions, and the first insulating layer covering the first inner peripheral surface and the plurality of second inner peripheral surfaces.

[0021] Preferably, the thermal printhead also has a second insulating layer covering the back side and connected to the first insulating layer, and the first electrode and the plurality of second electrodes are in contact with the second insulating layer.

[0022] Preferably, the thermal printhead also has a heat dissipation layer, which is located between the first electrode and the plurality of second electrodes in the sub-scanning direction and is formed in contact with the second insulating layer. When viewed along the thickness direction, the heat dissipation layer overlaps with the plurality of heat-generating parts.

[0023] Preferably, the thermal printhead also has a wiring board opposite to the back side and engaged with the first electrode and a plurality of second electrodes, the wiring board having a heat sink engaged with the heat dissipation layer.

[0024] Preferably, the thermal printhead also has a protective layer covering a portion of the main surface, the plurality of heating elements, and the wiring layer.

[0025] According to another embodiment of the first aspect of the present invention, a method for manufacturing a thermal printhead is provided. The method includes: forming a first recess in the thickness direction from the main surface of a substrate having a main surface facing the thickness direction and made of a semiconductor material; forming a resistive layer including a plurality of heating elements arranged in a main scanning direction on the main surface and in the first recess; forming a wiring layer on the resistive layer that is conductive to the plurality of heating elements; removing a portion of the substrate located on the side opposite to the main surface in the thickness direction; and forming an electrode on the substrate, the electrode being located on the side opposite to the wiring layer in the thickness direction relative to the substrate and conductive to the wiring layer. The step of forming the wiring layer includes forming a common wiring on a first side relative to the plurality of heating elements in the sub-scanning direction, and a first through wiring housed in the first recess and connected to the common wiring. The step of removing a portion of the substrate involves removing a portion of the substrate until a portion of the first through wiring is exposed from the substrate. The process of forming the aforementioned electrode includes the process of forming a first electrode that is in contact with the aforementioned common wiring. In the process of forming the aforementioned first electrode, the first electrode is formed in such a way that the first electrode is in contact with the aforementioned first through wiring.

[0026] Preferably, the manufacturing method further includes a step of forming a plurality of second recesses between the step of forming the first recess and the step of forming the resistive layer. The plurality of second recesses are recessed from the main surface of the substrate in the thickness direction and are located on the opposite side to the first recess in the sub-scanning direction relative to the plurality of heating elements. In the step of forming the resistive layer, a portion of the resistive layer is formed in the plurality of second recesses. The step of forming the wiring layer includes forming a plurality of independent wirings located on a second side relative to the plurality of heating elements in the sub-scanning direction, and a plurality of second through wirings respectively housed in the plurality of second recesses and respectively connected to the plurality of independent wirings. In the step of removing a portion of the substrate, a portion of the substrate is removed until a portion of the plurality of second through wirings is exposed from the substrate. The step of forming the electrodes includes forming a plurality of second electrodes that are respectively conductive to the plurality of independent wirings. In the step of forming the plurality of second electrodes, the plurality of second electrodes are formed in such a way that the plurality of second electrodes are respectively in contact with the plurality of second through wirings.

[0027] Preferably, the main surface includes a base surface and a convex surface protruding from the base surface in the thickness direction. Prior to the step of forming the first recess, a step of forming a convex portion on the substrate is also performed. This convex portion protrudes from the base surface in the thickness direction, extends along the main scanning direction, and includes the convex surface. In the step of forming the resistive layer, the plurality of heating elements are formed on the convex surface.

[0028] Preferably, the semiconductor material mentioned above includes a single crystal material of silicon.

[0029] Invention Effects

[0030] The thermal printhead and its manufacturing method according to the present invention enable more precise printing without increasing the size of the substrate.

[0031] Other features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Attached Figure Description

[0032] Figure 1 This is a plan view of a thermal printhead according to a first embodiment of the first aspect of the present invention.

[0033] Figure 2 yes Figure 1 A plan view of the main parts of the thermal printhead is shown.

[0034] Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0035] Figure 4 yes Figure 2 A magnified view of a portion of the image.

[0036] Figure 5 yes Figure 1 The diagram shows the bottom view of the main part of the thermal printhead.

[0037] Figure 6 It is along Figure 1 A cross-sectional view of line 006-006.

[0038] Figure 7 yes Figure 1 The diagram shows a cross-sectional view of the main part of the thermal printhead.

[0039] Figure 8 yes Figure 7 A magnified view of a portion of the image.

[0040] Figure 9 yes Figure 7 A magnified view of a portion of the image.

[0041] Figure 10 yes Figure 7A magnified view of a portion of the image.

[0042] Figure 11 It is along Figure 1 A cross-sectional view of line 011-011.

[0043] Figure 12 It is along Figure 1 A cross-sectional view of line 012-012.

[0044] Figure 13 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0045] Figure 14 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0046] Figure 15 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0047] Figure 16 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0048] Figure 17 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0049] Figure 18 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0050] Figure 19 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0051] Figure 20 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0052] Figure 21 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0053] Figure 22 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0054] Figure 23 This is an explanation Figure 1The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0055] Figure 24 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0056] Figure 25 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0057] Figure 26 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0058] Figure 27 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0059] Figure 28 This is an explanation Figure 1 The diagram shows a partially enlarged cross-sectional view of the manufacturing process of the main part of the thermal printhead.

[0060] Figure 29 This is an explanation Figure 1 The diagram shows a partially enlarged cross-sectional view of the manufacturing process of the main part of the thermal printhead.

[0061] Figure 30 This is an explanation Figure 1 The diagram shows a partially enlarged cross-sectional view of the manufacturing process of the main part of the thermal printhead.

[0062] Figure 31 This is an explanation Figure 1 The diagram shows a partially enlarged cross-sectional view of the manufacturing process of the main part of the thermal printhead.

[0063] Figure 32 This is an explanation Figure 1 The diagram shows a partially enlarged cross-sectional view of the manufacturing process of the main part of the thermal printhead.

[0064] Figure 33 This is an explanation Figure 1 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0065] Figure 34 This is a cross-sectional view of the main part of the thermal printhead according to the second embodiment of the first aspect of the present invention.

[0066] Figure 35 yes Figure 34 A magnified view of a portion of the image.

[0067] Figure 36This is a plan view illustrating a thermal printhead according to an embodiment of the second aspect of the present invention.

[0068] Figure 37 It is along Figure 36 A cross-sectional view of line 037-037.

[0069] Figure 38 yes Figure 37 A magnified view of a portion of the image.

[0070] Figure 39 yes Figure 36 The image shows an enlarged plan view of the main parts of the thermal printhead.

[0071] Figure 40 It means Figure 36 A cross-sectional view of one step in an example of the manufacturing method of a thermal printhead.

[0072] Figure 41 It means to continue Figure 40 A cross-sectional view of the process.

[0073] Figure 42 It means to continue Figure 41 A cross-sectional view of the process.

[0074] Figure 43 It means to continue Figure 42 A cross-sectional view of the process.

[0075] Figure 44 It means to continue Figure 43 A cross-sectional view of the process.

[0076] Figure 45 It means to continue Figure 44 A cross-sectional view of the process.

[0077] Figure 46 It means to continue Figure 45 A cross-sectional view of the process.

[0078] Figure 47 yes Figure 46 A magnified view of a portion of the image.

[0079] Figure 48 yes Figure 47 A magnified view of a portion of the image.

[0080] Figure 49 It means to continue Figure 46 A schematic plan view of the process.

[0081] Figure 50 It means to continue Figure 49 A schematic plan view of the process.

[0082] Figure 51 It means to continue Figure 50 A schematic plan view of the process.

[0083] Figure 52 It means to continue Figure 51 A schematic plan view of the process.

[0084] Figure 53 It means and Figure 36 The diagram shows a case where the thermal printhead is composed of a large number of single-chip substrates compared to the substrate.

[0085] Figure 54 It means and Figure 36 The diagram shows a case where the thermal printhead is composed of a small number of monolithic chips compared to the substrate.

[0086] Figure 55 This is a plan view showing a modified example of the thermal printhead of the second aspect of the present invention.

[0087] Figure 56 It is along Figure 55 A cross-sectional view of line 056-056.

[0088] Figure 57 This is a plan view of a thermal printhead according to a first embodiment of the third aspect of the present invention, showing the protective layer.

[0089] Figure 58 yes Figure 57 The diagram shows a plan view of the main parts of the thermal printhead, revealing the protective layer.

[0090] Figure 59 yes Figure 58 A magnified view of a portion of the image.

[0091] Figure 60 It is along Figure 57 A cross-sectional view of line 060-060.

[0092] Figure 61 yes Figure 57 The diagram shows a cross-sectional view of the main part of the thermal printhead.

[0093] Figure 62 yes Figure 61 A magnified view of a portion of the image.

[0094] Figure 63 yes Figure 57 The enlarged view shows the insulating layer, resistive layer, wiring layer, first substrate, second substrate, and multiple second interconnecting wirings.

[0095] Figure 64 It is along Figure 63 A cross-sectional view of line 064-064.

[0096] Figure 65 It is along Figure 63 The cross-sectional view of the 065-065 line only shows the substrate and the first connecting wiring.

[0097] Figure 66 yes Figure 64 A magnified view of a portion of the image.

[0098] Figure 67 It means Figure 57 The cross-sectional view of the modified thermal printhead shown only illustrates the substrate and the first interconnect wiring.

[0099] Figure 68 It means Figure 57 The cross-sectional view of the modified thermal printhead shown only illustrates the substrate and the first interconnect wiring.

[0100] Figure 69 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0101] Figure 70 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0102] Figure 71 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0103] Figure 72 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0104] Figure 73 This is an explanation Figure 57 A partially enlarged plan view of the manufacturing process of the main parts of the thermal printhead.

[0105] Figure 74 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0106] Figure 75 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0107] Figure 76 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0108] Figure 77 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0109] Figure 78 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0110] Figure 79 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0111] Figure 80 This is an explanation Figure 57 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0112] Figure 81 This is a plan view of a thermal printhead according to a second embodiment of the third aspect of the present invention, showing the protective layer.

[0113] Figure 82 This is a plan view of a thermal printhead according to a third embodiment of the third aspect of the present invention, showing the protective layer.

[0114] Figure 83 yes Figure 57 The enlarged view shows the insulation layer, resistive layer, wiring layer (except for a portion of the common wiring) and multiple second connection wirings.

[0115] Figure 84 This is a cross-sectional view of the main part of the thermal printhead according to the fourth embodiment of the third aspect of the present invention.

[0116] Figure 85 yes Figure 84 A magnified view of a portion of the image.

[0117] Figure 86 This is a cross-sectional view of the main part of the thermal printhead according to the fifth embodiment of the third aspect of the present invention.

[0118] Figure 87 yes Figure 86 A magnified view of a portion of the image.

[0119] Figure 88 This is an explanation Figure 86 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0120] Figure 89 This is a plan view of a thermal printhead according to a first embodiment of the fourth aspect of the present invention, showing the protective layer and the cover layer.

[0121] Figure 90 yes Figure 89 The diagram shows a plan view of the main parts of the thermal printhead, revealing the protective layer and the overlay layer.

[0122] Figure 91 yes Figure 90 A magnified view of a portion of the image.

[0123] Figure 92 It is along Figure 89 A cross-sectional view of line 092-092.

[0124] Figure 93 yes Figure 89 The diagram shows a cross-sectional view of the main part of the thermal printhead.

[0125] Figure 94 yes Figure 93 A magnified view of a portion of the image.

[0126] Figure 95 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0127] Figure 96 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0128] Figure 97 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0129] Figure 98 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0130] Figure 99 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0131] Figure 100 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0132] Figure 101 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0133] Figure 102 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0134] Figure 103 This is an explanation Figure 89 The diagram shows a cross-sectional view of the manufacturing process of the main parts of the thermal printhead.

[0135] Figure 104 yes Figure 89A partially enlarged cross-sectional view of a modified example of a thermal printhead.

[0136] Figure 105 This is an explanation Figure 89 A cross-sectional view of a modified example of the manufacturing process of the main part of the thermal printhead.

[0137] Figure 106 This is a plan view of a thermal printhead according to a second embodiment of the fourth aspect of the present invention, showing the protective layer and the cover layer.

[0138] Figure 107 yes Figure 106 The diagram shows a plan view of the main parts of the thermal printhead, revealing the protective layer and the overlay layer.

[0139] Figure 108 yes Figure 107 A magnified view of a portion of the image. Detailed Implementation

[0140] Various methods for carrying out the invention are described with reference to the accompanying drawings. Figures 1 to 108 Among them, Figures 1 to 35 These are illustrative diagrams relating to the first aspect of the invention. Similarly, Figures 36-56 These are explanatory diagrams relating to the second aspect of the invention. Figures 57-88 These are explanatory diagrams relating to the third aspect of the invention, and Figures 89-108 This is an explanatory diagram relating to the fourth aspect of the present invention.

[0141] First, refer to Figures 1-12 The thermal printhead A10 according to the first embodiment of the first aspect will be described. The thermal printhead A10 is a main component of a thermal printer. The thermal printhead A10 mainly includes a substrate 1, a first insulating layer 21, a second insulating layer 22, a resistive layer 3, a wiring layer 4, a first through wiring 511, a plurality of second through wirings 512, a first electrode 521, a plurality of second electrodes 522, a heat dissipation layer 53, and a protective layer 6. Based on this, the thermal printhead A10 also includes a wiring substrate 71, a heat sink 72, a plurality of drive elements 73, a plurality of first wires 74, a plurality of second wires 75, a sealing resin 76, and a connector 77. Here, Figure 1 The illustrations of the protective layer 6, multiple first conductors 74, multiple second conductors 75, and sealing resin 76 are omitted. Figures 2-4 The illustration of protective layer 6 is omitted in the text.

[0142] In this invention, the main scanning direction of the thermal printhead A10 is appropriately referred to as the "x-direction," and the sub-scanning direction (orthogonal to the main scanning direction) is referred to as the "y-direction." The direction extending through the thickness of the substrate 1 is referred to as the "z-direction." The z-direction is orthogonal to both the x-direction and the y-direction. In the following description, "viewing (along) the z-direction" and "viewing (along) the thickness direction" have the same meaning, and there are also cases where they are referred to as "viewing from above."

[0143] like Figure 6 As shown, in the thermal printhead A10, the main portion of the thermal printhead A10, including the substrate 1, is bonded to the wiring substrate 71. The wiring substrate 71 is bonded to the heat sink 72. The wiring substrate 71 forms a structure sandwiched between the main portion of the thermal printhead A10 and the heat sink 72 in the z-direction. A portion of the resistive layer 3 is formed on the substrate 1, and a plurality of heating elements 31 (described later) arranged in the x-direction are formed thereon. The plurality of heating elements 31 are selectively heated by a plurality of driving elements 73 mounted on the wiring substrate 71. The plurality of driving elements 73 are driven according to a print signal transmitted from the outside via the connector 77. Figure 6 As shown, the impression roller 79 of the thermal printer presses the recording medium 78, such as thermal paper, against a plurality of heating elements 31, thereby printing text onto the recording medium 78. For ease of explanation, [the following will be described]. Figure 6 The supply source side of the recording medium 78 ( Figure 6 The right side (in the middle) is called the "upstream side". (This will be...) Figure 6 One side of the discharge port of the recording medium 78 ( Figure 6 The left side of the middle is called the "downstream side".

[0144] Substrate 1 as Figure 1 As shown, the strip extends in the x direction when viewed along the z-axis. The substrate 1 is made of a semiconductor material. This semiconductor material contains single-crystal silicon (Si).

[0145] like Figure 6 As shown, substrate 1 has a main surface 10 and a back surface 13. Both the main surface 10 and the back surface 13 of substrate 1 are surfaces with a Miller index of (100). The main surface 10 and the back surface 13 face opposite sides to each other in the z-direction. In the thermal printhead A10, the main surface 10 and the back surface 13 are... Figure 6 The embossing rollers 79 are opposite each other, and the back surface 13 is opposite to the wiring substrate 71. (As shown) Figure 7 As shown, the main surface 10 includes a base surface 11 and a convex surface 12. The base surface 11 is parallel to the back surface 13. The convex surface 12 protrudes from the base surface 11 in the z-direction. The convex surface 12 extends along the x-direction.

[0146] like Figure 8As shown, the convex surface 12 has a top surface 121 and a pair of inclined surfaces 122. The top surface 121 is located away from the base surface 11 in the z-direction and is parallel to the base surface 11. The pair of inclined surfaces 122 are arranged apart from each other in the y-direction. The pair of inclined surfaces 122 are connected to the top surface 121 and the base surface 11. The pair of inclined surfaces 122 are inclined relative to the base surface 11 in such a way that they move closer to each other as they move from the base surface 11 to the top surface 121. The inclination angle α of each of the pair of inclined surfaces 122 relative to the base surface 11 is the same.

[0147] like Figure 7 As shown, a protrusion 17, a first through-hole 18, and a plurality of second through-holes 19 are formed on the substrate 1. The protrusion 17 protrudes from the base surface 11 in the z-direction and extends along the x-direction. A convex surface 12 is the surface of the protrusion 17. Therefore, the structure of the convex surface 12 is a structure formed based on the shape of the protrusion 17. The first through-hole 18 is located on one side (downstream side) in the y-direction relative to the protrusion 17. The plurality of second through-holes 19 are located on the other side (upstream side) in the y-direction relative to the protrusion 17. That is, the plurality of second through-holes 19 are located on the opposite side of the first through-hole 18 in the y-direction relative to the plurality of heating portions 31 (described later) of the resistive layer 3. The first through-hole 18 and the plurality of second through-holes 19 penetrate the substrate 1 from the base surface 11 (main surface 10) to the back surface 13. Figure 2 and Figure 5 As shown, viewed along the z-direction, the first through-section 18 forms a slit extending in the x-direction. Figure 4 As shown, when viewed along the z-direction, the multiple second through sections 19 are arranged in an alternating configuration relative to the x-direction.

[0148] like Figure 7 As shown, substrate 1 has a first inner peripheral surface 181 and a plurality of second inner peripheral surfaces 191. Each of the first inner peripheral surface 181 and the plurality of second inner peripheral surfaces 191 is connected to a base surface 11 (main surface 10) and a back surface 13. The first inner peripheral surface 181 defines a first through-hole 18. The first inner peripheral surface 181 forms a plurality of regions that are inclined relative to the base surface 11 and the back surface 13. Among the plurality of regions, a pair of regions located at intervals in the y-direction are inclined relative to the base surface 11 and the back surface 13, moving closer to each other as they move from the base surface 11 towards the back surface 13. Each of the plurality of second inner peripheral surfaces 191 defines any one of the plurality of second through-holes 19. Each of the plurality of second inner peripheral surfaces 191 is erected along the z-direction.

[0149] First insulating layer 21 Figure 7As shown, the substrate 1 is covered by a main surface 10, a first inner peripheral surface 181, and a plurality of second inner peripheral surfaces 191. The substrate 1 is electrically insulated from the resistive layer 3, the wiring layer 4, the first through wiring 511, and the plurality of second through wirings 512 by a first insulating layer 21. The first insulating layer 21 is, for example, made of silicon dioxide (TEOS-SiO2) using tetraethyl orthosilicate (TEOS) as a raw material. The thickness of the first insulating layer 21 is, for example, 1 μm or more and 15 μm or less.

[0150] Second insulating layer 22 Figure 7 As shown, the back surface 13 of the substrate 1 is covered. At the boundaries of the first inner peripheral surface 181 and multiple second inner peripheral surfaces 191 of the substrate 1 with the back surface 13, a second insulating layer 22 is connected to the first insulating layer 21. Through the second insulating layer 22, the substrate 1 is electrically insulated relative to the first electrode 521, the multiple second electrodes 522, and the heat dissipation layer 53. The second insulating layer 22 is, for example, made of silicon dioxide or silicon nitride (Si3N4). Figure 9 and Figure 10 As shown, a first opening 221 and a plurality of second openings 222 are formed in the second insulating layer 22. In the z-direction, the first opening 221 and the second openings 222 penetrate the second insulating layer 22. The first opening 221 communicates with the first through-port 18 of the substrate 1. The plurality of second openings 222 communicate with the plurality of second through-ports 19 of the substrate 1, respectively.

[0151] Resistor layer 3 Figures 7-10 As shown, the resistive layer 3 is formed on the main surface 10 of the substrate 1. The resistive layer 3 is in contact with the first insulating layer 21. Thus, in the thermal printhead A10, the first insulating layer 21 is sandwiched between the substrate 1 and the resistive layer 3. Furthermore, a portion of the resistive layer 3 is housed in the first through-hole 18 and a plurality of second through-holes 19 of the substrate 1. The resistive layer 3 is, for example, made of tantalum nitride (TaN). The thickness of the resistive layer 3 is, for example, 0.02 μm or more and 0.1 μm or less.

[0152] like Figure 2 , Figure 3 and Figure 8 As shown, the resistive layer 3 includes a plurality of heating elements 31. In the resistive layer 3, the plurality of heating elements 31 are portions exposed from the wiring layer 4. By selectively energizing the wiring layer 4 relative to the plurality of heating elements 31, the plurality of heating elements 31 will... Figure 6 The recording medium 78 shown is locally heated. Multiple heating elements 31 are arranged in the x-direction. Among the multiple heating elements 31, two adjacent heating elements 31 in the x-direction are positioned away from each other. Multiple heating elements 31 are formed on the top surface 121 of the substrate 1 on the convex surface 12. Figure 6 As shown, in a thermal printer, the impression roller 79 is opposite to a plurality of heating elements 31.

[0153] Wiring layer 4, as Figures 7-10 The resistive layer 3 is formed thereon. The wiring layer 4 forms conductive paths for energizing the plurality of heat-generating parts 31 of the resistive layer 3. The resistivity of the wiring layer 4 is lower than that of the resistive layer 3. The wiring layer 4 is, for example, a metal layer made of copper (Cu). An example of the thickness of the wiring layer 4 is 0.3 μm or more and 2.0 μm or less. Alternatively, the wiring layer 4 can be a structure consisting of two metal layers: a titanium (Ti) layer stacked on the resistive layer 3 and a copper layer stacked on the titanium layer. In this case, an example of the thickness of the titanium layer is 0.1 μm or more and 0.2 μm or less.

[0154] like Figure 2 As shown, wiring layer 4 includes a common wiring 41 and multiple independent wirings 42. The common wiring 41 is located on one side (downstream side) in the y-direction relative to the multiple heating elements 31 of resistive layer 3. The multiple independent wirings 42 are located on the other side (upstream side) in the y-direction relative to the multiple heating elements 31. Figure 3 As shown, viewed along the z-direction, multiple regions of the resistive layer 3 sandwiched between the common wiring 41 and multiple individual wirings 42 constitute multiple heat-generating parts 31. As will be described later, a predetermined positive voltage is supplied to the common wiring 41 from the power supply terminals (not shown) of the connector 77.

[0155] like Figure 2 and Figure 3 As shown, the common wiring 41 has a base 411 and a plurality of extensions 412. In the y-direction, the base 411 is located furthest from the plurality of heat-generating portions 31 of the resistive layer 3. The base 411, viewed along the z-direction, is a strip extending in the x-direction. Viewed along the z-direction, the base 411 overlaps with the first through-hole 18 of the substrate 1. The plurality of extensions 412 are strips extending in the y-direction from the end of the base 411 opposite to the protrusion 17 of the substrate 1 towards the plurality of heat-generating portions 31. The plurality of extensions 412 are arranged along the x-direction. A portion of each of the plurality of extensions 412 is formed on one of a pair of inclined surfaces 122 of the substrate 1 opposite to the base 411. Therefore, a portion of the common wiring 41 is formed on the downstream side of the inclined surface 122 of the pair of inclined surfaces 122. In the common wiring 41, current flows from the base 411 to the plurality of heat-generating portions 31 via the plurality of extensions 412.

[0156] like Figure 2 and Figure 4As shown, each of the multiple individual wirings 42 has a base 421 and an extension 422. In the y-direction, the base 421 is located at the position furthest from the multiple heat-generating portions 31 of the resistive layer 3. The bases 421 of the multiple individual wirings 42 are arranged in a staggered configuration relative to the x-direction. Viewed along the z-direction, the bases 421 of the multiple individual wirings 42 overlap with the multiple second through portions 19 of the substrate 1, respectively. The extension 422 is a strip-shaped portion extending in the y-direction from the end of the base 421 opposite to the protrusion 17 of the substrate 1 toward the multiple heat-generating portions 31. The extensions 422 of the multiple individual wirings 42 are arranged along the x-direction. The extension 422 of each of the multiple individual wirings 42 is formed on the inclined surface 122 of the substrate 1 opposite to the base 421 of the multiple individual wirings 42. Therefore, a portion of each of the multiple individual wirings 42 is formed on the upstream side of the inclined surface 122 of the pair of inclined surfaces 122. In each of the plurality of independent wirings 42, current flows from the base 421 through the extension 422 to any of the plurality of heating elements 31. Viewed along the z-direction, each of the plurality of heating elements 31 is sandwiched between any of the extensions 422 of the plurality of independent wirings 42 and any of the extensions 412 of the common wiring 41.

[0157] First through wiring 511, as shown Figure 7 and Figure 9 As shown, the first through-hole 511 is housed within the first through-hole 18 of the substrate 1. The first through-hole wiring 511 has a base layer 511A and a main body layer 511B. The base layer 511A is formed along the first inner peripheral surface 181 of the substrate 1 and contacts the resistive layer 3. The base layer 511A is connected to the base 411 of the common wiring 41. Therefore, the first through-hole wiring 511 is connected to the common wiring 41. Furthermore, the base layer 511A communicates with the first opening 221 of the second insulating layer 22. The base layer 511A is made of the same metal layer as the metal layer forming the wiring layer 4. The main body layer 511B is surrounded by the base layer 511A and fills the first through-hole 18. The volume of the main body layer 511B is larger than the volume of the base layer 511A. The main body layer 511B is, for example, made of copper.

[0158] Multiple second through wiring 512 such Figure 7 and Figure 10 As shown, multiple second through-sections 19 are respectively housed in the substrate 1. Multiple second through-wires 512 are each formed along any one of the multiple second inner peripheral surfaces 191 of the substrate 1 and are in contact with the resistive layer 3. The multiple second through-wires 512 are respectively connected to the bases 421 of the multiple individual wires 42. Therefore, each of the multiple second through-wires 512 is connected to any one of the multiple individual wires 42. Furthermore, the multiple second through-wires 512 are respectively connected to the multiple second openings 222 of the second insulating layer 22. Each of the multiple second through-wires 512 is formed of the same metal layer as the metal layer constituting the wiring layer 4.

[0159] First electrode 521 Figure 5 and Figure 7 As shown, it is formed on the back surface 13 of the substrate 1. The first electrode 521 is in contact with the second insulating layer 22. The first electrode 521 is a strip extending in the x direction when viewed along the z-direction. When viewed along the z-direction, the first electrode 521 overlaps with at least a portion of the first through-hole 18 of the substrate 1. Figure 9 As shown, the first electrode 521 has a base layer 521A and a main layer 521B. The base layer 521A is in contact with the second insulating layer 22. Furthermore, the base layer 521A is in contact with the resistive layer 3 and the base layer 511A of the first through wiring 511 in the first opening 221 of the second insulating layer 22. Thus, the first electrode 521 is connected to the first through wiring 511 and is conductive to the common wiring 41 via the first through wiring 511. A predetermined positive voltage is applied to the first electrode 521. The base layer 521A consists of two metal layers: a barrier layer in contact with the second insulating layer 22, the resistive layer 3, and the first through wiring 511, and a seed layer stacked on the barrier layer. The barrier layer is, for example, made of titanium. The seed layer is, for example, made of copper. The main layer 521B is stacked on the base layer 521A. In the first electrode 521, the main layer 521B becomes the main conductive path. The main layer 521B is, for example, a metal layer made of copper.

[0160] like Figure 5 and Figure 7 As shown, a plurality of second electrodes 522 are formed on the back surface 13 of the substrate 1. The plurality of second electrodes 522 are in contact with the second insulating layer 22. Each of the plurality of second electrodes 522 is rectangular in shape when viewed along the z-direction. Viewed along the z-direction, the plurality of second electrodes 522 overlap with respect to the plurality of second through-holes 19 of the substrate 1. Figure 10 As shown, each of the plurality of second electrodes 522 has a base layer 522A and a main layer 522B. The base layer 522A is in contact with the second insulating layer 22. Furthermore, the base layer 522A is in contact with the resistive layer 3 and any of the plurality of second through-wires 512 in any of the plurality of second openings 222 of the second insulating layer 22. Thus, each of the plurality of second electrodes 522 is connected to any of the second through-wires 512 and is electrically connected to any of the plurality of individual wirings 42 via the second through-wires 512. The base layer 522A is composed of a metal layer. This metal layer is the same as the metal layer of the base layer 521A constituting the first electrode 521. The main layer 522B is stacked on the base layer 522A. In each of the plurality of second electrodes 522, the main layer 522B becomes the primary conductive path. The main layer 522B is composed of a metal layer. This metal layer is the same as the metal layer of the main layer 521B constituting the first electrode 521.

[0161] Heat dissipation layer 53 Figure 5and Figure 7 As shown, a heat dissipation layer 53 is formed on the back surface 13 of the substrate 1 and is formed in contact with the second insulating layer 22. In the y-direction, the heat dissipation layer 53 is located between the first electrode 521 and the plurality of second electrodes 522. Viewed along the z-direction, the heat dissipation layer 53 appears as a strip extending in the x-direction. Viewed along the z-direction, the heat dissipation layer 53 overlaps with the plurality of heat-generating portions 31 of the resistive layer 3. Figure 8 As shown, the heat dissipation layer 53 has a base layer 53A and a main layer 53B. The base layer 53A is in contact with the second insulating layer 22. The base layer 53A is composed of a metal layer. This metal layer is the same as the metal layer of the base layer 521A constituting the first electrode 521. The main layer 53B is stacked on the base layer 53A. The main layer 53B is composed of a metal layer. This metal layer is the same as the metal layer of the main layer 521B constituting the first electrode 521.

[0162] Protective layer 6 Figure 7 As shown, a portion of the main surface 10 of the cover substrate 1 and a portion of the first through wiring 511, as well as a plurality of heating elements 31 of the resistive layer 3 and the wiring layer 4. The protective layer 6 has electrical insulation properties. The protective layer 6 is, for example, made of any one of silicon dioxide, silicon nitride, silicon carbide (SiC), and aluminum nitride (AlN). Alternatively, the protective layer 6 may be a laminate made of a variety of these materials. The thickness of the protective layer 6 is, for example, 1.0 μm or more and 10 μm or less. In a thermal printer, Figure 6 The recording medium 78 shown is pressed by the impression roller 79 onto the area of ​​the protective layer 6 covering the multiple heating elements 31.

[0163] Wiring board 71 Figure 6 As shown, it is disposed opposite to the back surface 13 of the substrate 1. Figure 1 As shown, viewed along the z-direction, the area of ​​the wiring board 71 is larger than that of the substrate 1. Viewed along the z-direction, the wiring board 71 is a rectangular shape with the x-direction as its long side. The wiring board 71 is, for example, a PCB substrate. The substrate 1, multiple driving elements 73, and connectors 77 are mounted on the wiring board 71.

[0164] like Figure 11 and Figure 12 As shown, the wiring substrate 71 has a heat sink 711 and wiring 712. The heat sink 711 extends through the wiring substrate 71 in the z-direction. The heat sink 711 is, for example, a metal layer formed of copper. A heat dissipation layer 53 is bonded to the heat sink 711. The wiring 712 is disposed on the upper surface of the wiring substrate 71. The wiring 712 forms a conduction path in the wiring substrate 71 for a first electrode 521, a plurality of second electrodes 522, a plurality of driving elements 73, and a connector 77. The first electrode 521 and a plurality of second electrodes 522 are respectively bonded to the wiring 712.

[0165] Radiator 72 Figure 6 The wiring substrate 71 is located on the opposite side of the substrate 1 in the z-direction. The wiring substrate 71 is bonded to the heat sink 72. When the thermal printhead A10 is in use, a portion of the heat generated from the plurality of heat-generating parts 31 of the resistive layer 3 is conducted to the heat sink 72 via the substrate 1 and the heat dissipation layer 53. The heat conducted to the heat sink 72 is dissipated to the outside. The heat sink 72 is made of, for example, aluminum (Al).

[0166] Multiple drive elements 73 such Figure 1 and Figure 6 As shown, the wiring substrate 71 is mounted via an electrically insulating die bonding material (not shown). Multiple driving elements (driver ICs) 73 are each semiconductor elements constituting various circuits. Each driving element 73 is coupled to one end of a plurality of first wires 74 and one end of a plurality of second wires 75. The other end of each of the plurality of first wires 74 is coupled to a wiring 712 of the wiring substrate 71 to which multiple second electrodes 522 are joined. The other end of each of the plurality of second wires 75 is coupled to a wiring 712 that is connected to a connector 77.

[0167] With the above structure, printing signals, control signals, and a specified positive voltage are input from the outside via connector 77 to multiple drive elements 73. Based on these electrical signals, the multiple drive elements 73 perform switching operations, thereby selectively applying a specified positive voltage or 0V to multiple independent wirings 42. Since a specified positive voltage is applied to the common wiring 41, when 0V is applied to any of the multiple independent wirings 42, current flows from the common wiring 41 to any of the multiple heating elements 31 of the resistive layer 3 that are connected to that independent wiring 42. Thus, the multiple heating elements 31 selectively heat up.

[0168] Sealing resin 76 Figure 6 The diagram shows a portion of a plurality of drive elements 73, a plurality of first wires 74, a plurality of second wires 75, and a wiring substrate 71. The sealing resin 76 is electrically insulating. The sealing resin 76 is, for example, a black and soft synthetic resin used as an underfill.

[0169] Connector 77 Figure 1 and Figure 6 The connector 77 is mounted on one end (upstream side) of the wiring board 71 in the y-direction. The connector 77 is connected to a thermal printer. The connector 77 has multiple pins (not shown). A portion of these pins are conductive to the wiring 712 engaged with the first electrode 521. The remaining pins are conductive to the wiring 712 of the wiring board 71, which is engaged with multiple second conductors 75.

[0170] Next, based on Figures 13-34Here, an example of the manufacturing method for the thermal printhead A10 will be explained. Figures 13-33 (but besides) Figures 28-32 The cross-sectional position of ) corresponds to the main part representing the thermal printhead A10. Figure 7 The cross-sectional positions are the same.

[0171] Initially, such as Figure 13 and Figure 14 As shown, a protrusion 17 is formed on the substrate 81.

[0172] First, such as Figure 13 The first mask layer 891 is formed covering the substrate 81. The substrate 81 is made of a semiconductor material. The semiconductor material includes a single crystal of silicon. The substrate 81 is a silicon wafer. A structure formed by connecting multiple substrates 1 in a direction orthogonal to the z-direction corresponds to the substrate 81. The substrate 81 has a first surface 81A and a second surface 81B. The first surface 81A and the second surface 81B face opposite sides to each other in the z-direction. Both the first surface 81A and the second surface 81B of the substrate 81 have a Miller index of (100). The first mask layer 891 is formed to cover the first surface 81A and the second surface 81B. The first mask layer 891 is made of silicon nitride. When forming the first mask layer 891, firstly, a thin film of silicon nitride covering the first surface 81A and the second surface 81B is formed using thermal CVD (Chemical Vapor Deposition). Then, a portion of the area of ​​the thin film of silicon nitride covering the first surface 81A is removed using photolithography patterning and reactive ion etching (RIE). Thus, a first mask layer 891 is formed that covers a portion of the first surface 81A and the second surface 81B.

[0173] Next, as Figure 14 As shown, a main surface 10 and a protrusion 17 are formed on a substrate 81. The main surface 10 and the protrusion 17 are formed by... Figure 13 The area of ​​the first surface 81A exposed from the first mask layer 891 is formed by wet etching using an aqueous solution of potassium hydroxide (KOH). This etching is anisotropic. Next, the area of ​​the first mask layer 891 covering the first surface 81A is removed by wet etching using hydrofluoric acid (HF). Through the above processes, a main surface 10 including a base surface 11 and a convex surface 12, and a protrusion 17 are formed on the substrate 81. The convex surface 12 protrudes from the base surface 11 in the z-direction. The protrusion 17 protrudes from the base surface 11 in the z-direction and extends along the x-direction. The protrusion 17 includes the convex surface 12. The area of ​​the first surface 81A covered by the first mask layer 891 becomes the top surface 121 of the convex surface 12. Furthermore, the inclination angle α of each pair of inclined surfaces 122 of the convex surface 12 relative to the base surface 11 (refer to...) Figure 8 All are the same. This is because the protrusion 17 is formed by anisotropic etching.

[0174] Next, as Figure 15 and Figure 16 As shown, a first recess 811 is formed in the substrate 81, which is recessed from the base surface 11 (main surface 10) in the z direction.

[0175] First, such as Figure 15 As shown, a second mask layer 892 is formed covering the main surface 10 of the substrate 81. The second mask layer 892 is made of silicon nitride. During the formation of the second mask layer 892, a thin film of silicon nitride covering the main surface 10 is first formed using thermal CVD. Then, a portion of the thin film of silicon nitride covering the substrate 11 is removed by photolithography patterning and reactive ion etching. Thus, the second mask layer 892 covering a portion of the main surface 10 is formed.

[0176] Next, as Figure 16 As shown, a first recess 811 is formed in the substrate 81. The first recess 811 is formed by... Figure 15 The area of ​​the base surface 11 exposed from the second mask layer 892, as shown, is formed by wet etching using an aqueous solution of potassium hydroxide. This etching is anisotropic. Finally, the second mask layer 892 is removed by wet etching using hydrofluoric acid. Through the above processes, a first recess 811 is formed on the substrate 81. Further, a first inner peripheral surface 181 defining the first recess 811 is formed on the substrate 81.

[0177] Next, as Figure 17 and Figure 18 As shown, a plurality of second recesses 812 are formed on the substrate 81, recessed from the base surface 11 (main surface 10) in the z-direction. The plurality of second recesses 812 are recessed relative to each other in the y-direction. Figure 24 The multiple heating elements 31 of the resistive layer 3 shown are located on the opposite side of the first recess 811.

[0178] First, such as Figure 17 As shown, a third mask layer 893 is formed covering the main surface 10 and the first inner peripheral surface 181 of the substrate 81. The third mask layer 893 is formed of silicon nitride. During the formation of the third mask layer 893, firstly, a thin film of silicon nitride covering the main surface 10 and the first inner peripheral surface 181 is formed using thermal CVD. Next, a portion of the thin film of silicon nitride covering the substrate 11 is removed using photolithography patterning and reactive ion etching. Thus, the third mask layer 893 covering a portion of the main surface 10 and the first inner peripheral surface 181 is formed.

[0179] Next, as Figure 18 As shown, a plurality of second recesses 812 are formed on the substrate 81. The plurality of second recesses 812 are formed relative to... Figure 17Each of the multiple regions of the base surface 11 exposed from the third mask layer 893 is formed using a deep RIE (Rear-In Etching). Finally, the third mask layer 893 is removed by using hydrofluoric acid wet etching. Through the above processes, a plurality of second recesses 812 are formed on the substrate 81. Furthermore, a plurality of second inner peripheral surfaces 191, each defining a plurality of second recesses 812, are formed on the substrate 81.

[0180] Next, as Figure 19 As shown, a first insulating layer 21 is formed covering the main surface 10, the first inner peripheral surface 181, and a plurality of second inner peripheral surfaces 191 of the substrate 81. The first insulating layer 21 is formed by repeatedly laminating a TEOS-SiO2 thin film using plasma CVD.

[0181] Next, as Figures 20-24 The resistive layer 3 and wiring layer 4 are shown to be formed. The resistive layer 3 includes a plurality of heating elements 31 arranged in the x-direction. The wiring layer 4 is electrically connected to the plurality of heating elements 31. Furthermore, the process of forming the wiring layer 4 includes the process of forming a common wiring 41, a plurality of independent wirings 42, a first through wiring 511, and a plurality of second through wirings 512. In the substrate 81, the common wiring 41 is relative to... Figure 24 The multiple heating elements 31 of the resistive layer 3 shown are located on one side (downstream side) in the y-direction. In the substrate 81, multiple independent wirings 42 are positioned relative to... Figure 24 The plurality of heating elements 31 shown are located on the opposite side (upstream side) in the y direction. A first through wiring 511 is housed in a first recess 811 of the substrate 81 and is connected to a common wiring 41. Second through wirings 512 are respectively housed in a plurality of second recesses 812 of the substrate 81 and are respectively connected to a plurality of individual wirings 42.

[0182] First, such as Figure 20 As shown, a resistive film 82 is formed on the main surface 10 of the substrate 81, in the first recess 811 and a plurality of second recesses 812 of the substrate 81. The resistive film 82 is formed in such a way that it covers the entire surface of the first insulating layer 21. The resistive film 82 is formed by sputtering a thin film of tantalum nitride onto the first insulating layer 21.

[0183] Next, as Figure 21 As shown, a conductive layer 83 is formed covering the entire surface of the resistive film 82. The conductive layer 83 is formed by sputtering multiple copper thin films onto the resistive film 82. Alternatively, when forming the conductive layer 83, a method can be used whereby a titanium thin film is sputtered onto the resistive film 82, and then multiple copper thin films are sputtered onto the titanium thin film. Thus, the base layer 511A of the first through-wire 511 is formed in the first recess 811 of the substrate 81. Furthermore, multiple second through-wires 512 are formed relative to multiple second recesses 812 of the substrate 81.

[0184] Next, as Figure 22 As shown, a main layer 511B is formed in the first recess 811 of the substrate 81, forming a first through-line 511. The main layer 511B is formed of copper. The main layer 511B is formed by electroplating the conductive layer 83 as a conductive path after photolithographic patterning relative to the conductive layer 83. Thus, the first through-line 511 is formed in the first recess 811.

[0185] Next, as Figure 23 As shown, after photolithographic patterning is performed relative to the conductive layer 83, a portion of the conductive layer 83 is removed. This removal is performed using wet etching with a mixed solution of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). As a result, a common wiring 41 and multiple individual wirings 42 are formed on the resistive film 82. Therefore, the formation of the wiring layer 4 is completed in this process. Furthermore, the region of the resistive film 82 formed on the top surface 121 (convex surface 12) of the substrate 81 is exposed from the wiring layer 4.

[0186] Next, as Figure 24 As shown, after photolithographic patterning of the resistive film 82, wiring layer 4, and the main layer 511B of the first through wiring 511, a portion of the resistive film 82 is removed. This removal is performed using reactive ion etching. As a result, a resistive layer 3 is formed on the main surface 10 of the substrate 81, as well as a first recess 811 and a plurality of second recesses 812 on the substrate 81. A plurality of heat-generating portions 31 are formed on the top surface 121 of the substrate 81.

[0187] Next, as Figure 25 As shown, a protective layer 6 is formed covering a portion of the main surface 10 of the substrate 81 and a portion of the first through wiring 511, as well as a plurality of heating portions 31 of the resistive layer 3 and the wiring layer 4. The protective layer 6 is formed by laminating thin films of silicon nitride using plasma CVD.

[0188] Next, as Figure 26As shown, a portion of the substrate 81 located on the side opposite to the main surface 10 in the z-direction is removed. This removal is performed using grinding. This removal continues until a portion of the first through-wire 511 and a portion of each of the plurality of second through-wires 512 are exposed from the substrate 81. Thus, a portion of the substrate 81 including the second surface 81B and the area of ​​the first mask layer 891 covering the second surface 81B are removed. Furthermore, a back surface 13 is formed on the substrate 81 facing the side opposite to the main surface 10 in the z-direction. A portion of the first through-wire 511 and a portion of each of the plurality of second through-wires 512 are exposed from the back surface 13. Also, a portion of the first insulating layer 21 and the resistive layer 3 are exposed from the back surface 13. Through this process, the first recess 811 of the substrate 81 becomes a first through-part 18. Simultaneously, the plurality of second recesses 812 of the substrate 81 become a plurality of second through-parts 19.

[0189] Next, as Figure 27 As shown, a second insulating layer 22 is formed covering the back surface 13 of the substrate 81. The second insulating layer 22 is formed of silicon nitride. A first opening 221 and a plurality of second openings 222 extending in the z-direction are formed in the second insulating layer 22. During the formation of the second insulating layer 22, firstly, a thin film of silicon nitride covering the back surface 13 is formed using plasma CVD. Then, a portion of the thin film of silicon nitride covering the back surface 13 is removed using photolithography patterning and reactive ion etching. Thus, the second insulating layer 22 covering the back surface 13 is formed, and the first opening 221 and a plurality of second openings 222 are formed in the second insulating layer 22. Figure 28 and Figure 29 As shown, at the boundaries of the first inner peripheral surface 181 and the plurality of second inner peripheral surfaces 191 of the substrate 81 with the back surface 13, the second insulating layer 22 is connected to the first insulating layer 21. Furthermore, as... Figure 28 As shown, a portion of the resistive layer 3 and a portion of the base layer 511A of the first through wiring 511 are exposed from the first opening 221. Figure 29 As shown, a portion of the resistive layer 3 and a portion of each of the plurality of second through wirings 512 are exposed from any of the plurality of second openings 222.

[0190] Next, as Figures 28-33 The diagram shows the formation of electrodes (a first electrode 521 and a plurality of second electrodes 522) and a heat dissipation layer 53. The first electrode 521 is conductive to a common wiring 41. The plurality of second electrodes 522 are conductive to a plurality of individual wirings 42 respectively. The first electrode 521, the plurality of second electrodes 522, and the heat dissipation layer 53 are disposed on the back side 13 of the substrate 81 and in contact with the second insulating layer 22. That is, the first electrode 521, the plurality of second electrodes 522, and the heat dissipation layer 53 are located on the opposite side of the wiring layer 4 in the z-direction relative to the substrate 81.

[0191] First, such as Figure 28 and Figure 29 The substrate layer 84 covering the second insulating layer 22 is shown. The substrate layer 84 is formed by sputtering a thin film of titanium onto the second insulating layer 22, followed by sputtering a thin film of copper relative to the titanium film. Thus, the substrate layer 84 is also formed in the first opening 221 of the second insulating layer 22 and a plurality of second openings 222 of the second insulating layer 22. The substrate layer 84 formed in the first opening 221 is in contact with the resistive layer 3 and the base layer 511A of the first through wiring 511. The substrate layer 84 formed in the plurality of second openings 222 is in contact with the resistive layer 3 and a plurality of second through wirings 512.

[0192] Next, as Figures 30-32 As shown, multiple host layers 85 are formed on a substrate layer 84. The multiple host layers 85 are formed of copper. The multiple host layers 85 are formed by electroplating with the substrate layer 84 as a conductive path after photolithographic patterning of the substrate layer 84.

[0193] Next, as Figure 33 The diagram shows the removal of multiple areas of the base layer 84 not covered by the main layer 85. This removal is performed using wet etching with a mixed solution of sulfuric acid and hydrogen peroxide. This forms a first electrode 521, multiple second electrodes 522, and a heat dissipation layer 53.

[0194] Next, the substrate 81 is cut along the x and y directions, thereby dividing the substrate 81 into single pieces. This yields the main portion of the thermal printhead A10, which includes the substrate 1. Next, multiple drive elements 73 and connectors 77 are mounted on the wiring board 71, multiple first wires 74 and multiple second wires 75 are joined, and a sealing resin 76 is formed. Next, a heat dissipation layer 53 is bonded to the heat sink 711 of the wiring board 71, and a first electrode 521 and multiple second electrodes 522 are bonded to the wiring 712 of the wiring board 71. Finally, the wiring board 71 is bonded to the heat sink 72. Through the above processes, the thermal printhead A10 is obtained.

[0195] Next, the function and effect of the thermal printhead A10 will be explained.

[0196] The thermal printhead A10 includes: a substrate (semiconductor substrate) 1 having a main surface 10 and a back surface 13 and formed of a semiconductor material; a wiring layer 4 formed on a resistive layer 3; and a first electrode 521 formed on the back surface 13. The wiring layer 4 has a common wiring 41 located on one side (downstream side) in the y-direction relative to the plurality of heating elements 31 of the resistive layer 3. On the other hand, a first through portion 18 is formed in the substrate 1, extending from the main surface 10 to the back surface 13. The first through portion 18 houses the first through wiring 511. The first through wiring 511 is connected to the common wiring 41 and the first electrode 521. According to this structure, on the main surface 10, the common wiring 41 is not configured with a large width on the other side (upstream side) in the y-direction relative to the plurality of heating elements 31, thus ensuring the conduction path of the common wiring 41 in the thermal printhead A10. Therefore, without further increasing the area of ​​the main surface 10, the number of individual wirings 42 located on the opposite side of the multiple heating elements 31 in the y-direction can be further increased. Thus, the width (length in the x-direction) of each of the multiple heating elements 31 can be reduced, and their number can be further increased. Therefore, based on the thermal printhead A10, more precise printing can be performed without increasing the size of the substrate 1.

[0197] In the thermal printhead A10, since the current flowing from the multiple heating elements 31 to the common wiring 41 can be made to flow more quickly, the thickness of the common wiring 41 can be made larger than the thickness of each of the multiple individual wirings 42. Therefore, by having the first through wiring 511 and the first electrode 521, the thermal printhead A10 can further reduce the area of ​​the common wiring 41 when viewed along the z-direction. As a result, warping of the substrate 1 in the z-direction caused by the difference between the coefficient of linear expansion of the substrate 1 and the coefficient of linear expansion of the wiring layer 4 can be suppressed.

[0198] The thermal printhead A10 also has a plurality of second electrodes 522 formed on the back surface 13 of the substrate 1. On the other hand, a plurality of second through-sections 19 are formed on the substrate 1, extending from the main surface 10 to the back surface 13, and located on the opposite side of the first through-section 18 in the y-direction relative to the plurality of heating elements 31. A plurality of second through-section wirings 512 are respectively housed in the plurality of second through-sections 19. Each of the plurality of second through-section wirings 512 is connected to any one of the plurality of individual wirings 42 and any one of the plurality of second electrodes 522. Thus, the substrate 1 is configured such that the plurality of second electrodes 522 and the first electrode 521 are formed at the same position in the z-direction. Therefore, it is possible to avoid the complexity of the construction of the wiring substrate 71 that connects the plurality of second electrodes 522 and the first electrode 521.

[0199] The main surface 10 of the substrate 1 includes a base surface 11 and a convex surface 12 protruding from the base surface 11 in the z-direction. The convex surface 12 extends along the x-direction. A plurality of heating elements 31 are formed on the convex surface 12. Thus, when the thermal printhead A10 is used, the recording medium 78 (see reference) can be heated. Figure 6 The contact area is smaller than that of the thermal printhead A10. Therefore, the printing quality in the recording medium 78 caused by the multiple heating elements 31 can be improved.

[0200] Furthermore, the convex surface 12 includes: a top surface 121 parallel to the base surface 11 of the substrate 1; and a pair of inclined surfaces 122 connected to the top surface 121 and the base surface 11 and located apart from each other in the y-direction. A plurality of heating elements 31 are formed on the top surface 121. A portion of the common wiring 41 and a portion of each of the plurality of independent wirings 42 are formed on either of the pair of inclined surfaces 122. Thus, viewed along the z-direction, the y-direction dimensions of each of the plurality of heating elements 31 can be made smaller, and when the thermal printhead A10 is used, the contact area of ​​the recording medium 78 relative to the thermal printhead A10 can be made smaller. Therefore, heat generation in the thermal printhead A10 can be suppressed, and the printing quality on the recording medium 78 can be further improved.

[0201] In substrate 1, a pair of inclined surfaces 122 are inclined relative to base surface 11 in such a way that they approach each other as they move from base surface 11 to top surface 121. This shape of the convex surface 12 is caused by forming the protrusion 17 on substrate 81 through anisotropic etching in the manufacturing method of thermal printhead A10. This is because the semiconductor material constituting substrate 81 contains a single crystal material of silicon.

[0202] The thermal printhead A10 also includes a first insulating layer 21 and a second insulating layer 22. The first insulating layer 21 covers not only the main surface 10 of the substrate 1, but also the first inner peripheral surface 181 defining the first through-hole 18 and the respective plurality of second inner peripheral surfaces 191 defining the plurality of second through-holes 19. The second insulating layer 22 covers the back surface 13 of the substrate 1 and is connected to the first insulating layer 21. Thus, even if the thermal printhead A10 has a structure having a first through-wire 511, a plurality of second through-wires 512, a first electrode 521, and a plurality of second electrodes 522, it is possible to achieve electrical insulation between these conductive elements and the substrate 1. Therefore, in the wiring layer 4, short circuits between the common wiring 41 and the plurality of independent wirings 42 can be prevented.

[0203] The thermal printhead A10 also includes a heat dissipation layer 53 formed in the y-direction between the first electrode 521 and the plurality of second electrodes 522 and in contact with the second insulating layer 22. Viewed along the z-direction, the heat dissipation layer 53 overlaps with the plurality of heat-generating elements 31. Therefore, when the thermal printhead A10 is used, a portion of the heat dissipated from the plurality of heat-generating elements 31 can be rapidly conducted from the substrate 1 to the heat dissipation layer 53.

[0204] The thermal printhead A10 also has a wiring board 71 that is bonded to the first electrode 521 and a plurality of second electrodes 522. The wiring board 71 has a heat sink 711 that is bonded to the heat dissipation layer 53. Thus, in the above-described case, the heat conducted to the heat dissipation layer 53 is rapidly released to the outside via the heat sink 711.

[0205] based on Figure 34 and Figure 35 The thermal printhead A20 according to the second embodiment of the first aspect of the present invention will be described. In these figures, elements that are the same as or similar to the thermal printhead A10 described above are labeled with the same reference numerals, and repeated descriptions are omitted. Figure 34 The cross-sectional position and the representation of the above thermal printhead A10 Figure 6 The cross-sectional positions are the same.

[0206] In the thermal printhead A20, the structure of the convex surface 12 of the substrate 1 is different from that of the thermal printhead A10 described above.

[0207] like Figure 34 and Figure 35 As shown, each of the pair of inclined surfaces 122 of the convex surface 12 includes a first region 122A and a second region 122B. The first region 122A is connected to the base surface 11 of the substrate 1. The second region 122B is connected to the top surface 121 of the convex surface 12 and the first region 122A. In each of the pair of inclined surfaces 122, the inclination angle α2 of the second region 122B relative to the base surface 11 is smaller than the inclination angle α1 of the first region 122A relative to the base surface 11.

[0208] Next, the function and effect of the thermal printhead A20 will be explained.

[0209] The thermal printhead A20 includes: a substrate (semiconductor substrate) 1 having a main surface 10 and a back surface 13, and formed of a semiconductor material; a wiring layer 4 formed on a resistive layer 3; and a first electrode 521 formed on the back surface 13. The wiring layer 4 includes a common wiring 41 located on one side of the plurality of heating elements 31 in the y-direction relative to the resistive layer 3. On the other hand, a first through portion 18 is formed on the substrate 1, extending from the main surface 10 to the back surface 13. A first through wiring 511 is housed in the first through portion 18. The first through wiring 511 is connected to the common wiring 41 and the first electrode 521. Therefore, based on the thermal printhead A20, more precise printing can be performed without increasing the size of the substrate 1.

[0210] In the thermal printhead A20, a pair of inclined surfaces 122 (convex surfaces 12) of the substrate 1 each include a first region 122A and a second region 122B. The first region 122A is connected to the base surface 11 of the substrate 1. The second region 122B is connected to the top surface 121 of the convex surface 12 and the first region 122A. In each of the pair of inclined surfaces 122, the inclination angle α2 of the second region 122B relative to the base surface 11 is smaller than the inclination angle α1 of the first region 122A relative to the base surface 11. By forming this structure, the surface of the protective layer 6 formed along the convex surface 12 becomes smoother. Therefore, when the thermal printhead A20 is used, Figure 6 When the recording medium 78 comes into contact with the protective layer 6, the dynamic friction of the recording medium 78 relative to the protective layer 6 decreases. Therefore, firstly, it is possible to suppress paper scraps caused by the recording medium 78 from adhering to the protective layer 6. Secondly, since wear on the protective layer 6 is suppressed, the lifespan of the thermal printhead A20 is extended.

[0211] This invention is not limited to the embodiments described in the first aspect above. The specific structure of each part of this invention can be freely modified in various ways.

[0212] [Explanation of reference numerals in the accompanying drawings of the first aspect of the embodiment]

[0213] A10, A20: Thermal printhead 1: Substrate

[0214] 10: Main surface; 11: Base surface; 12: Convex surface

[0215] 121: Top surface 122: Inclined surface

[0216] 122A: First area; 122B: Second area; 13: Back side

[0217] 17: convex portion 18: first through portion 181: first inner peripheral surface

[0218] 19: Second through section; 191: Second inner circumferential surface

[0219] 21: First insulating layer; 22: Second insulating layer

[0220] 221: First opening 222: Second opening

[0221] 3: Resistor layer; 31: Heating element; 4: Wiring layer

[0222] 41: Common Wiring 411: Base

[0223] 412: Extension section; 42: Independent wiring.

[0224] 421: Base; 422: Extension; 511: First through wiring

[0225] 511A: Basic level; 511B: Main level

[0226] 512: Second through wiring

[0227] 521: First electrode; 521A: Substrate layer; 521B: Main body layer

[0228] 522: Second electrode; 522A: Substrate layer; 522B: Main body layer

[0229] 53: Heat dissipation layer; 53A: Base layer; 53B: Main body layer

[0230] 6: Protective layer; 71: Wiring board; 711: Heat sink

[0231] 712: Wiring; 72: Heat sink; 73: Drive component

[0232] 74: First conductor; 75: Second conductor; 76: Sealing resin

[0233] 77: Connector; 78: Recording medium; 79: Impression roller

[0234] 81: Substrate; 81A: First side; 81B: Second side

[0235] 811: First recessed portion 812: Second recessed portion 82: Resistor film

[0236] 83: Conductive layer; 84: Substrate layer; 85: Main layer

[0237] 891: First mask layer; 892: Second mask layer

[0238] 893: Third mask layer α, α1, α2: tilt angle.

[0239] Next, regarding an embodiment of the second aspect of the present invention, refer to... Figures 36-56 Explanation will be provided. In Figures 36-56 (Second aspect) The reference numerals used in the accompanying drawings are the same as those in Figures 1 to 35 The reference numerals used in the (first aspect) drawings are unrelated; there are cases where the same reference numerals denote different parts, and there are also cases where different reference numerals denote the same or similar parts. The same applies to the drawings describing the embodiments of the third and fourth aspects, which are described later, where the reference numerals used in the drawings in different aspects are unrelated to each other.

[0240] In existing thermal printheads disclosed in Patent Document 1, the print length in the main scanning direction can vary. To manufacture thermal printheads with different print lengths in the main scanning direction, the Si wafer needs to be divided into multiple wafers of different lengths. The more types of thermal printheads with different print lengths there are, the lower the efficiency of manufacturing thermal printheads from the Si wafer may become. Therefore, the problem to be solved by the second aspect of the present invention is to provide a technique that can improve the manufacturing efficiency of thermal printheads with various print lengths in the main scanning direction.

[0241] Figures 36-39 This describes a thermal printhead according to one embodiment of the second aspect. The thermal printhead B10 of this embodiment includes a printhead substrate 1, a wiring substrate 5, multiple wires 61, 62, 63, multiple driver ICs 7, a resin section 78, a heat dissipation component 81, and a support component 82. The thermal printhead B10 is assembled on a printhead that passes through an impression roller 99 (see reference 1). Figure 39 The printer is a component that performs printing on the supplied printing medium (illustration omitted). Examples of printing media include thermal paper used for making barcodes or receipts.

[0242] Figure 36 This is a plan view representing the thermal printhead B10. Figure 37 It is along Figure 36 A cross-sectional view of line 037-037. Figure 38 This is a cross-sectional view of the main parts of the thermal printhead B10, which is... Figure 39 A magnified cross-sectional view of a portion of the image. Figure 39 This is an enlarged plan view showing the main parts of the thermal printhead B10. Figure 36 and Figure 39 For ease of understanding, protective layer 2 has been omitted. Figure 36 and Figure 39 For ease of understanding, the resin part 78 has been omitted.

[0243] like Figure 37As shown, in the thermal printhead B10, the printhead substrate 1 and the wiring substrate 5 are mounted adjacent to each other in the y-direction on the heat dissipation member 81. In this embodiment, the printhead substrate 1 is supported by the heat dissipation member 81 via the support member 82. A plurality of heating elements 41 (described later) arranged in the y-direction are formed on the printhead substrate 1. The heating elements 41 are selectively heated and driven by the drive IC 7 mounted on the wiring substrate 5, and print characters on the printing medium pressed by the impression roller 99 against the heating elements 41 according to the printing signal sent from the outside via the connector 59.

[0244] Head substrate 1 Figure 36 , Figure 38 , Figure 39 As shown, it has a substrate 10, an insulating layer 19, a protective layer 2, an electrode layer 3, and a resistive layer 4.

[0245] The substrate 10 is made of Si single-crystal semiconductor. As a constituent material of the substrate 10, a Si wafer is suitable. Figure 36 As shown, the substrate 10, viewed in the z-direction, is an elongated rectangular shape with the x-direction as its longer side and the y-direction as its shorter side. The substrate 10 is composed of multiple monolithic chips 10A. The multiple monolithic chips 10A are arranged in the x-direction.

[0246] The single-chip 10A has a first side surface 101 and a second side surface 102. The second side surface 102 is the end face facing the x-direction (the side facing the main scanning direction). The first side surface 101 is the end face facing the other side of the x-direction (the other side facing the main scanning direction).

[0247] In this embodiment, a pair of adjacent monolithic chips 10A in the x-direction are closely connected to each other. The first side surface 101 of the monolithic chip 10A located on one side of the x-direction (the side of the main scanning direction) is perpendicular to the x-direction. Similarly, the second side surface 102 of the monolithic chip 10A located on the other side of the x-direction (the other side of the main scanning direction) is also perpendicular to the x-direction. In this pair of adjacent monolithic chips 10A in the x-direction, the first side surface 101 of the monolithic chip 10A on one side of the x-direction and the second side surface 102 of the monolithic chip 10A on the other side of the x-direction are closely connected to each other.

[0248] The size of the substrate 10 (a plurality of monolithic chips 10A arranged in the x-direction) is not limited. For example, the dimension in the x-direction is, for example, 50 mm or more and 400 mm or less, the dimension in the y-direction is, for example, 3 mm or more and 10 mm or less, and the dimension in the z-direction is, for example, 725 μm. Alternatively, as an example of the size of the monolithic chip 10A, the dimension in the x-direction is, for example, 5 mm or more and 15 mm or less. In the substrate 10, the side in the y-direction closer to the driver IC7 is the upstream side, and the side farther from the driver IC7 is the downstream side. The printing medium is conveyed from the upstream side to the downstream side in the y-direction via the impression roller 99.

[0249] Substrate 10 (each single chip 10A) such as Figures 37-39 As shown, it has a main surface 11 and a protrusion 12. The main surface 11 faces upward in the z-direction. In this invention, the main surface 11 extends along the xy plane (a plane defined by the x and y directions, as well as other planes) and is a plane that is substantially parallel to the xy plane. The main surface 11 is a plane with a Miller index of (100). The protrusion 12 protrudes from the main surface 11 in the z-direction and extends in the x-direction. The protrusion 12 is formed on the downstream side of the main surface 11. The shape of the cross-section of the protrusion 12 along the yz plane is the same as that in the x-direction. The dimension in the y-direction of the end of the protrusion 12 on the lower side in the z-direction is, for example, about 500 μm, and the dimension in the y-direction of the end on the upper side in the z-direction (top surface 121 described later) is, for example, about 200 μm. In addition, the dimension in the z-direction of the protrusion 12 is, for example, about 150 μm.

[0250] like Figure 38 As shown, the protrusion 12 has a top surface 121 and a pair of inclined surfaces 122. The top surface 121 is parallel to the main surface 11 and is generally planar. The top surface 121 is an elongated rectangular shape extending longer in the x direction when viewed in the z direction. The z-direction dimension of the protrusion 12 is the separation distance between the top surface 121 and the main surface 11 in the z direction. The pair of inclined surfaces 122 sandwich the top surface 121 in the y direction. In addition, the pair of inclined surfaces 122 are connected to the main surface 11 and the top surface 121 respectively, and are sandwiched by them in the y direction. Each inclined surface 122 is inclined relative to the main surface 11 and the top surface 121 in such a way that it decreases as it moves further away from the top surface 121 in the y direction. In other words, the pair of inclined surfaces 122 are closer to each other in the y direction as they move further away from the main surface 11 in the z direction. Each inclined surface 122 is generally planar. The inclination angle of each inclined surface 122 relative to the main surface 11 is, for example, 54.8 degrees. Each inclined surface 122 is a (111) surface.

[0251] In this embodiment, the protrusions 12 are respectively disposed on a plurality of monolithic chips 10A. The protrusions 12 are aligned in the y-direction among the plurality of monolithic chips 10A. Thus, the protrusions 12 in each of the plurality of monolithic chips 10A overlap when viewed in the x-direction.

[0252] Insulation layer 19 Figure 38 As shown, an insulating layer 19 is formed on the main surface 11 of the substrate 10, covering the substrate 10 (each single-chip 10A). The insulating layer 19 contacts the main surface 11, the top surface 121 of the protrusion 12, and a pair of inclined surfaces 122. The insulating layer 19 is used to more reliably insulate the substrate 10 (each single-chip 10A) relative to the resistive layer 4 and the electrode layer 3. The insulating layer 19 can be formed in the substrate 10 (each single-chip 10A) in the region where the resistive layer 4 or the electrode layer 3 is formed. The insulating layer 19 is made of an insulating material, such as SiO2 or SiN (silicon nitride), preferably TEOS-SiO2 (SiO2 formed from TEOS (tetraethyl orthosilicate) as a raw material). The thickness of the insulating layer 19 is not particularly limited, for example, it is more than 1 μm and less than 10 μm.

[0253] Resistor layer 4 Figure 38 As shown, a resistive layer 4 is formed on an insulating layer 19 and supported by a substrate 10 (a plurality of monolithic chips 10A). The resistive layer 4 is formed by sandwiching the insulating layer 19 across the main surface 11 and the protrusion 12. The resistive layer 4 is formed, for example, of TaN (tantalum nitride). The thickness of the resistive layer 4 is not particularly limited, but is, for example, 0.02 μm or more and 0.1 μm or less (preferably around 0.08 μm). In this embodiment, the resistive layer 4 is disposed separately from each of the plurality of monolithic chips 10A.

[0254] Resistor layer 4 Figure 36 , Figure 38 and Figure 39 The diagram shows multiple heating elements 41. These heating elements 41 are portions of the resistive layer 4 that are not covered by the electrode layer 3 (described later). Each heating element 41 is selectively energized, thereby locally heating the printing medium. The heating elements 41 are arranged in the x-direction and spaced apart from each other in the x-direction. The region where the heating elements 41 are formed in the y-direction is defined as a portion or all of the y-direction region including the top surface 121 of the protrusion 12.

[0255] like Figure 36 , Figure 39 As shown, multiple heating elements 41 are disposed on each of the multiple single-chip 10A. In this embodiment, the multiple heating elements 41 disposed on the substrate 10 are arranged at a certain interval in the x-direction, covering all of the multiple single-chip 10A. The boundary of a pair of adjacent single-chip 10A in the x-direction is located between a pair of adjacent heating elements 41 in the x-direction.

[0256] The electrode layer 3 forms a conductive path for energizing the multiple heating elements 41. The electrode layer 3 is stacked on the resistive layer 4 and supported by the substrate 10 (multiple monolithic chips 10A). The electrode layer 3 is formed of a metal material with a lower resistance than the resistive layer 4, such as Cu (copper). The thickness of the electrode layer 3 is not particularly limited, for example, it is 0.3 μm or more and 2.0 μm or less. Alternatively, the electrode layer 3 can also be a structure formed by stacking a Cu layer and a Ti (titanium) layer. In this case, the Ti layer is located between the Cu layer and the resistive layer 4, for example, with a thickness of about 100 nm. In this embodiment, the electrode layer 3 and the multiple monolithic chips 10A are respectively disposed separately.

[0257] In this embodiment, such as Figure 39 As shown, the electrode layer 3 in each single chip 10A includes multiple independent electrodes 31, a common electrode 32, and multiple relay electrodes 33.

[0258] The common electrode 32 has multiple common electrode extensions 321, multiple branches 322, and a base 323. The common electrode extensions 321 are strip-shaped extending along the y-direction. The common electrode extensions 321 are disposed upstream of the heating element 41 in the y-direction. The multiple common electrode extensions 321 are arranged at predetermined intervals in the x-direction (main scanning direction).

[0259] A pair of branch portions 322 are connected to the downstream end of each common electrode extension 321 in the y-direction. Each branch portion 322 is a strip extending in the y-direction. The downstream end of each branch portion 322 in the y-direction extends onto an inclined surface 122 upstream in the y-direction. The pair of branch portions 322 connected to the common electrode extension 321 are spaced apart from each other in the x-direction and contact a pair of adjacent heating portions 41 in the x-direction. Thus, each common electrode extension 321 is connected to a pair of adjacent heating portions 41 in the x-direction via the pair of branch portions 322. The base 323 is a strip extending in the x-direction and is disposed biased against the drive IC7 in the y-direction. The upstream end of each common electrode extension 321 in the y-direction is connected to the base 323.

[0260] Multiple independent electrodes 31 are separated from each other in the x-direction. The independent electrodes 31 are positioned upstream of the heating element 41 in the y-direction. Each independent electrode 31 has an independent electrode extension 311 and an electrode pad portion 312. The independent electrode extension 311 is a strip-shaped portion extending generally along the y-direction. The downstream end of the independent electrode extension 311 in the y-direction extends onto an inclined surface 122 upstream in the y-direction and contacts the heating element 41. The electrode pad portion 312 is connected to the upstream end of the independent electrode extension 311 in the y-direction. The electrode pad portion 312 is the portion where the conductive wire 61 is bonded.

[0261] Each individual electrode extension 311 is spaced apart from the common electrode extension 321 in the x-direction. The individual electrode extension 311 is adjacent to each common electrode extension 321 on both sides in the x-direction. That is, each common electrode extension 321 is sandwiched between two individual electrode extensions 311 that are adjacent on both sides in the x-direction.

[0262] The heating element 41 that contacts the independent electrode extension 311 and the heating element 41 that is connected to the common electrode extension 321 are adjacent to each other. More specifically, the heating element 41 that contacts one of the two independent electrode extensions 311 that sandwich the common electrode extension 321 and one of the pair of heating elements 41 that are connected to the common electrode extension 321 are adjacent to each other. The heating element 41 that contacts the other of the two independent electrode extensions 311 that sandwich the common electrode extension 321 and the other of the pair of heating elements 41 that are connected to the common electrode extension 321 are adjacent to each other.

[0263] Multiple relay electrodes 33 are arranged along the x-direction. The multiple relay electrodes 33 are positioned downstream of the multiple heating elements 41 in the y-direction, sandwiching the heating elements 41 and located opposite the common electrode 32 and the multiple independent electrodes 31 in the y-direction. Each relay electrode 33 is in contact with a pair of adjacent heating elements 41 in the x-direction. The multiple relay electrodes 33 are electrically disposed between one of the multiple independent electrodes 31 and the common electrode 32. Each relay electrode 33 has a pair of relay electrode extensions 331 and a connecting portion 332.

[0264] like Figure 38 , Figure 39 As shown, each relay electrode extension 331 is a strip extending in the y-direction. The multiple relay electrode extensions 331 are spaced apart from each other in the x-direction. The upstream end of each relay electrode extension 331 in the y-direction extends onto the inclined surface 122 in the downstream y-direction. Each pair of relay electrode extensions 331 constituting each relay electrode 33 contacts a pair of adjacent heating elements 41 in the x-direction. One of the pairs of relay electrode extensions 331 in each relay electrode 33 is positioned opposite any of the multiple branch portions 322 in the y-direction, sandwiching the heating element 41. The other pair of relay electrode extensions 331 in each relay electrode 33 is positioned opposite any of the multiple independent electrode extensions 311 in the y-direction, sandwiching the heating element 41.

[0265] Each connecting portion 332 extends along the x-direction. Each connecting portion 332 is connected to a pair of relay electrode extensions 331 in each relay electrode 33. Thus, the pair of relay electrode extensions 331 in each relay electrode 33 are mutually conductive.

[0266] Reference Figure 39A specific structural example of electrode layer 3 (multiple independent electrodes 31 and a common electrode 32) will be explained. The shapes of each independent electrode 31 and the common electrode 32 as viewed in the z-direction, i.e., the formation areas of each independent electrode 31 and the common electrode 32, are not limited to... Figure 39 of examples.

[0267] Protective layer 2, as Figure 38 As shown, the protective layer 2 covers the electrode layer 3 and the resistive layer 4. The protective layer 2 is made of an insulating material, such as any one of SiO2, SiN, SiC (silicon carbide), AlN (aluminum nitride), or a stack of two or more of them. The thickness of the protective layer 2 is not particularly limited, but is, for example, 1.0 μm or more and 10 μm or less. The protective layer 2 has a through-hole 21 for pads in the z-direction. The through-hole 21 exposes the electrode pad portions 312 of the plurality of independent electrodes 31.

[0268] Wiring board 5, as shown Figure 36 and Figure 37 As shown, the wiring board 5 is arranged adjacent to the head substrate 1 on the upstream side in the y-direction. The wiring board 5 is, for example, a PCB substrate. Figure 36 As shown, the wiring substrate 5, viewed in the z-direction, is an elongated rectangle with the x-direction as its longer side. A wiring pattern (detailed shape omitted from the diagram) is formed on the wiring substrate 5. This wiring pattern is as follows... Figure 39 The diagram shows an independent wiring section 51 and a common wiring section 52. (As shown...) Figure 37 As shown, the wiring board 5 is equipped with a connector 59 and a driver IC 7.

[0269] Connector 59 is used to connect the thermal printhead B10 to the printer (not shown). Connector 59 is as follows... Figure 37 It is installed on the wiring board 5 and connected to the wiring pattern of the wiring board 5.

[0270] Driver IC7, etc. Figure 36 and Figure 37 The configuration shown is on the wiring board 5. The driver IC 7 is a component that applies a potential to each individual electrode 31 and controls the current flowing to each heating element 41. For example... Figure 36 As shown, in this embodiment, a plurality of driver ICs 7 are mounted on the wiring substrate 5. These driver ICs 7 are arranged at intervals in the x-direction. For example, the plurality of driver ICs 7 are arranged such that one driver IC 7 is assigned to each of two adjacent monolithic chips 10A in the x-direction.

[0271] like Figure 39 As shown, the driver IC7 has multiple pad sections 71. The multiple pad sections 71 are formed, for example, in two rows.

[0272] Figure 39The multiple wires 61, 62, and 63 shown are formed of conductors such as Au. Wire 61 is bonded to the pad portion 71 of the driver IC7 and to the electrode pad portion 312 of the individual electrode 31. Thus, the driver IC7 is electrically connected to each individual electrode 31. Additionally, wire 61 crosses the base plate 323. Wire 62 is bonded to the pad portion 71 of the driver IC7 and to the individual wiring portion 51 of the wiring board 5. Thus, the driver IC7 and the connector 59 are electrically connected via the individual wiring portion 51. Wire 63 is bonded to the common electrode 32 (base plate 323) and to the common wiring portion 52 of the wiring board 5. Thus, the common electrode 32 is electrically connected to the common wiring portion 52.

[0273] The driver IC7 receives printing signals, control signals, and voltages supplied to multiple heating elements 41 via connector 59 from an external source. The multiple heating elements 41 are energized separately according to the printing signals and control signals, thereby selectively heating them.

[0274] The resin portion 78 is, for example, formed of black resin. Figure 37 , Figure 38 As shown, the resin portion 78 is formed as a crossover substrate 1 and a wiring substrate 5. The resin portion 78 covers a portion of the driver IC 7, multiple wires 61, 62, 63 and the protective layer 2, and includes the driver IC 7 and the multiple wires 61, 62, 63.

[0275] Heat dissipation component 81, such as Figure 36 , Figure 37 As shown, the support head substrate 1 (substrate 10, multiple single-chip 10A) and wiring substrate 5 are included. The heat dissipation component 81 is provided to dissipate a portion of the heat generated by the multiple heat-generating parts 41 to the outside. The heat dissipation component 81 is made of metal such as aluminum.

[0276] Support component 82, such as Figure 36 , Figure 37 As shown, the components are disposed on the heat dissipation component 81 and between the head substrate 1 (substrate 10, multiple single-chip 10A) and the heat dissipation component 81. In this embodiment, the multiple single-chip 10A are bonded to the support component 82. The support component 82 is made of a high-flatness material such as a Si board.

[0277] Next, an example of the manufacturing method of the thermal printhead B10 is provided. Figures 40-49 The following explanation will be provided. Figures 40-45 These are cross-sectional views showing one step in the manufacturing process of the thermal printhead B10, and... Figure 38 The enlarged view of the section shown corresponds to this.

[0278] First, such as Figure 40The prepared substrate 10' is shown. The substrate 10' is formed of a single-crystal Si semiconductor, such as a Si wafer. The substrate 10' has a main surface 11'. The main surface 11' is generally flat and faces upward in the z-direction. The main surface 11' is a (100) surface.

[0279] Next, as Figure 41 The protrusion 12 is formed as shown. The protrusion 12 is formed by forming a defined mask layer on a portion of the main surface 11'. Figure 40 and Figure 41 (Indicated by imaginary lines), and anisotropic etching is performed on the substrate 10'. In the process of forming the protrusion 12, anisotropic etching using an alkaline aqueous solution is performed, for example. Examples of this alkaline aqueous solution include KOH (potassium hydroxide) or TMAH (tetramethylammonium hydroxide). Thus, as... Figure 41 As shown, a substrate 10 is formed having a main surface 11 and a protrusion 12. The main surface 11 is the same (100) surface as the main surface 11'. The protrusion 12 has a top surface 121 and a pair of inclined surfaces 122. The pair of inclined surfaces 122 are (111) surfaces, inclined relative to the main surface 11 and the top surface 121. The inclination angle α1 of each inclined surface 122 is, for example, 54.8 degrees.

[0280] Next, as Figure 42 An insulating layer 19 is formed as shown. The insulating layer 19 is formed, for example, by depositing TEOS-SiO2 using CVD. The insulating layer 19 covers the main surface 11, a pair of inclined surfaces 122 of the protrusion 12, and the top surface 121.

[0281] Next, as Figure 43 The resistive film 4' is shown to be formed. The resistive film 4' is formed, for example, by sputtering a thin film of TaN on the insulating layer 19. The resistive film 4' covers the entire surface of the insulating layer 19.

[0282] Next, as Figure 44 The electrode film 3' is shown. The electrode film 3' is formed by, for example, depositing or sputtering to form a Cu layer. The electrode film 3' covers the entire surface of the resistive film 4'. Alternatively, in the formation of the electrode film 3', a Cu layer may be formed after a Ti layer has been formed on the resistive film 4'.

[0283] Next, as Figure 45 As shown, the electrode film 3' and the resistive film 4' are partially removed by selective etching. This results in the formation of a resistive layer 4 separated in the x-direction, and an electrode layer 3 covering the resistive layer 4 with a plurality of remaining heating elements 41. Here, the plurality of heating elements 41 are formed on the protrusion 12.

[0284] Next, as Figure 46As shown, the substrate 10 is cut along the x and y directions to divide it into multiple monolithic chips 10A (illustration omitted). Here, laser irradiation is used to cut the substrate 10 along a plane C1 perpendicular to the x direction and a plane C2 perpendicular to the y direction to divide it into multiple monolithic chips 10A. More specifically, by focusing the laser beam inside the substrate 10, which is made of Si single-crystal semiconductor, the substrate 10 is divided into monolithic chips 10A in a peeling manner. In this laser irradiation-based division of monolithic chips 10A, there is almost no cutting width, almost no cutting chips are generated, and the cut surface is smooth.

[0285] like Figure 47 , Figure 48 As shown, in the process of dividing the substrate 10 into multiple single-chip 10A using laser irradiation, the cutting of the substrate 10 on the vertical plane C1 relative to the x-direction is performed at a position between a pair of adjacent heating elements 41 in the x-direction. Figure 45 In the formation of the resistive layer 4 and the electrode layer 3 shown, the resistive layer 4 is formed separately in regions corresponding to the plurality of monolithic chips 10A, and the electrode layer 3 is formed separately in regions corresponding to the plurality of monolithic chips 10A. Thus, at the cut lines of the substrate 10 ( Figure 47 , Figure 48 As shown, the resistive layer 4 and the electrode layer 3 are not formed on the vertical plane C1 relative to the x direction and the vertical plane C2 relative to the y direction.

[0286] Next, as Figure 49 As shown, a mounting substrate 91 is prepared, on which a support member 82 and a wiring substrate 5 are disposed. The support member 82 is, for example, a Si board. The wiring substrate 5 is, for example, a PCB substrate. The support member 82 and the wiring substrate 5 are temporarily fixed to the mounting substrate 91 by adhesive tape (not shown).

[0287] Next, as Figure 50 , Figure 51 As shown, multiple monolithic chips 10A are arranged along the x-direction on a support member 82, and the back surfaces of the monolithic chips 10A are bonded to the upper surface of the support member 82. Bonding of the monolithic chips 10A to the support member 82 is performed using, for example, a UV adhesive. Figure 51As shown, multiple single-chip 10A are joined to the support member 82 in a manner that aligns with the wiring substrate 5 and is adjacent to each other in the x-direction. In the pair of adjacent single-chip 10A in the x-direction, the first side 101 of the single-chip 10A located on one side of the x-direction (one side of the main scanning direction) and the second side 102 of the single-chip 10A located on the other side of the x-direction (the other side of the main scanning direction) are in close contact with each other. Thus, a substrate 10 composed of multiple single-chip 10A is disposed on the support member 82. Multiple heating elements 41 disposed on the substrate 10 are arranged at a certain interval across all of the multiple single-chip 10A in the x-direction.

[0288] Next, a protective layer 2 (not shown) is formed. The protective layer 2 is formed, for example, by depositing SiN, onto the insulating layer 19, electrode layer 3, and resistive layer 4 on the substrate 10 using CVD. Furthermore, the protective layer 2, having pad openings 21 (not shown), is formed in a predetermined area on the substrate 10 using a mask, for example. Through these processes, a head substrate 1 disposed on the support member 82 is obtained.

[0289] Next, as Figure 52 As shown, multiple driver ICs 7 are mounted on the wiring substrate 5. Next, multiple wires 61, 62, and 63 are bonded, and resin portions 78 are formed. Then, the support member 82, the head substrate 1, and the wiring substrate 5 are separated from the mounting substrate 91. Afterward, the head substrate 1 and wiring substrate 5 are bonded to the heat dissipation member 81, and connectors 59 are installed. In this way, a thermal printhead B10 can be manufactured.

[0290] Next, the effects of this embodiment will be explained.

[0291] In the thermal printhead B10, a resistive layer 4 and an electrode layer 3 are supported by a substrate 10 formed of Si single-crystal semiconductor. The resistive layer 4 includes a plurality of heating elements 41 arranged in the x-direction (main scanning direction). The substrate 10 is configured with a plurality of monolithic chips 10A arranged in the x-direction (main scanning direction). A plurality of heating elements 41 are disposed on each monolithic chip 10A. Furthermore, the boundary of an adjacent pair of monolithic chips 10A is located between an adjacent pair of heating elements 41 in the x-direction (main scanning direction). Thus, the plurality of heating elements 41 are appropriately arranged along the x-direction (main scanning direction) throughout the entire plurality of monolithic chips 10A.

[0292] In a structure where the substrate 10 is composed of multiple single-chip 10A, the length of the substrate 10 in the x-direction (main scanning direction) can be adjusted in various ways by appropriately selecting the number of single-chip 10A. Therefore, thermal printheads B10 with different printing lengths in the x-direction (main scanning direction) can be manufactured efficiently.

[0293] Figure 53 It indicates that with Figure 36 In contrast, the substrate 10 is composed of more individual chips 10A. By using a large number of individual chips 10A, the length of the substrate 10 in the x-direction (main scanning direction) can be appropriately extended. Therefore, the printing length in the x-direction (main scanning direction) can be extended without being limited by the size of the Si wafer, which is the material of the substrate 10. Thus, it is possible to make the thermal printhead B10, which uses Si as the substrate 10, longer.

[0294] Figure 54 It indicates that with Figure 36 In contrast, the substrate 10 is composed of a small number of single-chip 10A. By using a small number of single-chip 10A, it is easy to manufacture a thermal printhead B10 with a shorter printing length in the x-direction (main scanning direction). Furthermore, if the single-chip 10A is made into a chip with a smaller size in the x-direction, the printing length in the x-direction (main scanning direction) can be set more precisely.

[0295] In a pair of adjacent chips 10A along the x-direction (main scanning direction), the first side 101 and the second side 102 facing each other in the x-direction are perpendicular to the x-direction. With this structure, the chips 10A are arranged vertically along the x-direction (main scanning direction). Furthermore, the plurality of heating elements 41 disposed on the substrate 10 are all arranged at a certain interval along the x-direction (main scanning direction) of the chips 10A. The thermal printhead B10 with this structure can appropriately maintain print quality.

[0296] In the manufacturing of the thermal printhead B10, the substrate 10 is cut using laser irradiation during the process of dividing the substrate 10 into multiple single-chip 10A. By focusing the laser beam onto the substrate 10, which is formed of Si single-crystal semiconductor, the substrate 10 can be divided into multiple single-chip 10A with almost no cut width and smooth cut surfaces. According to this manufacturing method of the thermal printhead B10, the dimensional accuracy of the cut surfaces (first side 101 or second side 102) of the single-chip 10A is improved, allowing the resistive layer 4 (heating element 41) and electrode layer 3 to be positioned near these cut surfaces. Consequently, the multiple heating elements 41 can be arranged at a certain interval in the x-direction (main scanning direction) covering the entirety of the multiple single-chip 10A.

[0297] The electrode layers 3, supported by the substrate 10, are disposed separately in each of the plurality of monolithic chips 10A. Similarly, the resistive layers 4, also supported by the substrate 10, are disposed separately in each of the plurality of monolithic chips 10A. Thus, the formation regions of the electrode layers 3 and resistive layers 4 do not span the plurality of monolithic chips 10A. With this structure, poor conductivity can be prevented in the conduction paths leading to the plurality of heat-generating units 41.

[0298] The substrate 10 (multiple single-chip 10A) is bonded to the support member 82 and supported by the heat dissipation member 81 via the support member 82. By forming the support member 82 as a plate with high flatness, the inconsistency in the position of the multiple single-chip 10A in the z-direction (thickness direction) can be suppressed, and the inconsistency in the printing quality of the thermal printhead B10 can be suppressed.

[0299] The substrate 10 has a protrusion 12. The protrusion 12 protrudes from the main surface 11 of the substrate 10 and extends in the x-direction (main scanning direction). The protrusion 12 is disposed in a plurality of monolithic chips 10A, and a plurality of heating elements 41 are disposed on the protrusion 12. With this structure, the printing medium can reliably contact the protrusion 12 on which the plurality of heating elements 41 are disposed, and thus an improvement in print quality can be expected.

[0300] The thermal printhead and the method for manufacturing the thermal printhead according to the second aspect of the present invention are not limited to the embodiments described above. Various design changes can be made to the specific structure of each part of the thermal printhead and the specific processing of each step in the manufacturing method of the thermal printhead.

[0301] In the above embodiment, the example shown is that the substrate 10 (each single chip 10A) has a protrusion 12 protruding from the main surface 11, but it can also be formed without such a protrusion 12. In addition, it can also be formed with a heat storage layer inserted between the substrate 10 and the heating part 41 (resistive layer 4).

[0302] In the above embodiment, the case where the substrate 10 (each single chip 10A) is supported by the heat dissipation member 81 via the support member 82 has been described, but it is also possible to form a structure in which the substrate 10 (each single chip 10A) is directly supported on the heat dissipation member 81. Figure 55 , Figure 56 This illustrates a modified example of a thermal printhead B20. Compared to the thermal printhead B10 described above, the thermal printhead B20 does not have a support member 82. In the thermal printhead B20, multiple monolithic chips 10A (substrate 10) and wiring board 5 are directly bonded to the heat dissipation member 81.

[0303] The present invention is not limited to the embodiments of the second aspect described above. Various design changes can be made to the specific structures of the various parts of the present invention. Embodiments of the second aspect of the present invention include the structures described in the following appendices 1B to 20B.

[0304] Note 1B.

[0305] A thermal printhead comprising:

[0306] The substrate has a main surface facing one side in the thickness direction and is formed of a single-crystal Si semiconductor;

[0307] A resistive layer, supported by the aforementioned substrate, includes a plurality of heating elements arranged in the main scanning direction; and

[0308] The electrode layer is supported by the aforementioned substrate and is in communication with the aforementioned resistive layer.

[0309] The aforementioned substrate comprises multiple monolithic chips, each having a plurality of the aforementioned heating elements disposed thereon and arranged in the aforementioned main scanning direction.

[0310] The boundary of a pair of adjacent monolithic chips in the aforementioned main scanning direction is located between a pair of adjacent heat-generating parts in the aforementioned main scanning direction.

[0311] Note 2B.

[0312] In the thermal printhead described in Appendix 1B,

[0313] In a pair of adjacent monolithic chips along the main scanning direction, the monolithic chip located on one side of the main scanning direction has a first side facing the other side of the main scanning direction and perpendicular to the main scanning direction.

[0314] One of the two adjacent monolithic chips in the main scanning direction, located on the other side of the main scanning direction, has a second side facing the main scanning direction and perpendicular to the main scanning direction.

[0315] Note 3B.

[0316] In the thermal printhead described in Note 1B or 2B,

[0317] The aforementioned multiple heat-generating components, covering all of the aforementioned single-chip units, are arranged at a certain interval along the aforementioned main scanning direction.

[0318] Appendix 4B.

[0319] Thermal printheads described in any of Notes 1B to 3B

[0320] The electrode layers in each of the aforementioned single-chip units include a common electrode and multiple independent electrodes.

[0321] Note 5B.

[0322] Note 4B describes the thermal printhead.

[0323] The aforementioned common electrode has multiple common electrode extensions that are respectively connected to a pair of adjacent heating elements in the main scanning direction and extend in the sub-scanning direction.

[0324] The aforementioned independent electrode has an independent electrode extension that contacts the aforementioned heating part adjacent to the aforementioned heating part which is connected to the aforementioned common electrode extension, and extends in the aforementioned sub-scanning direction.

[0325] Note 6B.

[0326] Note 5B describes the thermal printhead.

[0327] The aforementioned common electrode includes a base body that is connected to the extension of each of the aforementioned common electrodes and extends in the aforementioned main scanning direction.

[0328] Note 7B.

[0329] Thermal printheads described in any of Notes 1B to 6B

[0330] The resistive layer is disposed on the substrate.

[0331] The electrode layer is disposed on the resistive layer.

[0332] Note 8B.

[0333] Thermal printheads described in any of Notes 1B to 7B

[0334] The aforementioned electrode layers are disposed separately on each of the aforementioned plurality of monolithic chips.

[0335] Note 9B.

[0336] Thermal printheads described in any of Notes 1B to 8B

[0337] The aforementioned resistive layers are disposed separately on each of the aforementioned plurality of monolithic chips.

[0338] Note 10B.

[0339] Thermal printheads described in any of Notes 1B to 9B

[0340] It also has a heat dissipation component to support the aforementioned multiple single-chip chips.

[0341] Note 11B.

[0342] Note 10B describes the thermal printhead.

[0343] It also has a support member disposed between the plurality of single-chip units and the heat dissipation component, wherein the plurality of single-chip units are coupled to the support member.

[0344] Note 12B.

[0345] Thermal printheads described in any of Notes 1B to 11B

[0346] It also has a driver IC that controls the current flowing to each of the aforementioned heat-generating parts.

[0347] Note 13B.

[0348] Note 12B describes the thermal printhead.

[0349] It also has wires connecting the aforementioned driver IC and the aforementioned electrode layer.

[0350] Note 14B.

[0351] The thermal printhead described in Appendix 12B or 13B

[0352] It also has a resin section that covers the aforementioned driver IC.

[0353] Note 15B.

[0354] The thermal printhead described in Appendix 14B

[0355] It also has a wiring board configured with the aforementioned driver IC.

[0356] Note 16B.

[0357] Thermal printheads described in any of Notes 1B to 15B

[0358] The aforementioned substrate has protrusions disposed on each of the plurality of monolithic chips, the protrusions protruding from the main surface and extending in the main scanning direction.

[0359] The aforementioned multiple heating elements are disposed on the aforementioned protrusion.

[0360] Note 17B.

[0361] Note 16B describes the thermal printhead.

[0362] The protrusions in the aforementioned multiple single-chip chips overlap each other when viewed in the aforementioned main scanning direction.

[0363] Note 18B.

[0364] A method for manufacturing a thermal printhead, comprising:

[0365] The process of preparing a substrate formed from Si single-crystal semiconductors;

[0366] The process of forming a resistive film on the above-mentioned substrate;

[0367] The process of forming an electrode film on the resistive film described above;

[0368] The process of forming an electrode layer and a resistive layer containing a plurality of heating elements arranged in the main scanning direction by partially removing the electrode film and the resistive film described above;

[0369] The process of cutting the aforementioned substrate into multiple monolithic chips by laser irradiation along a plane perpendicular to the main scanning direction and a plane perpendicular to the sub-scanning direction; and

[0370] The process of arranging multiple of the above-mentioned single-chip units on a support in a manner that is aligned along the main scanning direction.

[0371] In the process of dividing the chip into multiple single chips, the substrate is cut between a pair of adjacent heating elements in the main scanning direction.

[0372] Note 19B.

[0373] Appendix 18B describes the manufacturing method of the thermal printhead.

[0374] In the process of forming the electrode layer and the resistive layer containing a plurality of heating elements arranged in the main scanning direction, the resistive layers are formed and arranged separately from each other in regions corresponding to the plurality of single chips, and the electrode layers are arranged separately from each other in regions corresponding to the plurality of single chips.

[0375] Note 20B.

[0376] The manufacturing method of the thermal printhead is described in Appendix 18B or 19B.

[0377] It also includes an etching process, performed before the process of forming the resistive film, which involves anisotropic etching of the substrate.

[0378] In the above etching process, anisotropic etching is used to form a main surface facing the thickness direction and a protrusion protruding from the main surface on the substrate.

[0379] In the process of forming the above-mentioned multiple heating elements, multiple heating elements are formed on the above-mentioned protrusion.

[0380] [Explanation of reference numerals in the accompanying drawings of the second aspect of the embodiment]

[0381] B10, B20: Thermal Printhead 1: Printhead Baseboard

[0382] 10: Substrate 10': Substrate 10A: Monolithic Chip

[0383] 101: First side view; 102: Second side view; 11: Main face.

[0384] 11': main surface 12: convex portion 122: inclined surface

[0385] 19: Insulation layer 2: Protective layer

[0386] 21: Openings for pads; 3: Electrode layers

[0387] 3': Electrode film; 31: Independent electrode; 311: Independent electrode extension.

[0388] 312: Electrode pad section; 32: Common electrode

[0389] 321: Common electrode extension; 322: Branch section

[0390] 323: Base tube; 33: Relay electrode

[0391] 331: Relay electrode extension; 332: Connector; 4: Resistor layer

[0392] 4': Resistor film; 41: Heating element; 5: Wiring board

[0393] 51: Independent wiring section; 52: Common wiring section; 59: Connector

[0394] 61, 62, 63: Wires 7: Driver IC

[0395] 71: Solder pad section; 78: Resin section

[0396] 81: Heat dissipation component 82: Support component

[0397] 91: Mounting substrate; 99: Imprint roller.

[0398] Next, regarding the third aspect of the present invention, refer to Figures 57-88 Please provide an explanation.

[0399] Patent Document 2 discloses an example of a conventional thermal printhead. In conventional thermal printheads, a protrusion extending in the main scanning direction and protruding from the main surface is formed on the main surface of the substrate. For example, Patent Document 2... Figure 6 As shown, multiple heating elements are arranged on the protrusion in the main scanning direction. This structure allows the printing medium to reliably contact the heating elements, potentially leading to improved print quality.

[0400] The thermal printhead disclosed in Patent Document 2 can be used, for example, for barcode and QR code printing. Therefore, there is a need to further miniaturize this thermal printhead, and there is still room for improvement. Therefore, one of the problems to be solved by the third aspect of the present invention is to provide a thermal printhead capable of miniaturization.

[0401] based on Figures 57-68 The thermal printhead C10 of the first embodiment of the third aspect will be described. The thermal printhead C10 constitutes the thermal printer 100. Figure 60 The thermal printhead C10 mainly comprises a substrate 1, an insulating layer 21, a resistive layer 3, a wiring layer 4, and a protective layer 5. Based on this, the thermal printhead C10 has a first substrate 61, a second substrate 62, a first connecting wiring 63, multiple second connecting wirings 64, multiple driving elements 65, and a heat dissipation component 66. Figures 57-59 In the image, for ease of understanding, protective layer 5 is shown through the lens. Figure 63 For ease of understanding, the insulating layer 21, resistive layer 3, wiring layer 4, first substrate 61, second substrate 62, and second interconnecting wiring 64 are further shown in the diagram (see reference). Figure 57 ).exist Figure 63 In this diagram, the first substrate 61 and the second substrate 62 are represented by imaginary lines (dash lines). Figure 65 , Figure 67 and Figure 68 For ease of understanding, only the substrate 1 and the first connecting wiring 63 are shown in the diagram.

[0402] In the thermal printhead C10, such as Figure 60 As shown, substrate 1 is bonded to heat dissipation component 66. Substrate 1 supports first substrate 61 and second substrate 62. On substrate 1, a plurality of heat-generating elements 31 (described later) forming part of resistive layer 3 and arranged in the x-direction are formed. The plurality of heat-generating elements 31 are selectively heated by a plurality of driving elements 65 mounted on second substrate 62. The plurality of driving elements 65 are driven via connectors (not shown) mounted on first substrate 61 according to printing signals sent from the outside.

[0403] like Figure 60As shown, the thermal printer 100 includes a thermal printhead C10 and an impression roller 69. In the thermal printer 100, the impression roller 69 is configured to feed a recording medium 68, such as thermal paper. With the impression roller 69 pressing the recording medium 68 against a plurality of heating elements 31, the plurality of heating elements 31 print on the recording medium 68. In the thermal printer 100, other mechanisms (non-roller-shaped mechanisms) can be used instead of the impression roller 69. For example, a mechanism having a flat pressing surface can be cited as such a mechanism. A "flat surface" includes a curved surface with a sufficiently small curvature. In this invention, roller-shaped mechanisms and other mechanisms are collectively referred to as "impression components."

[0404] Substrate 1, such as Figure 57 As shown, it is a strip extending along the x-direction. The substrate 1 is formed of a semiconductor material. This semiconductor material is, for example, a single crystal of silicon (Si), but the invention is not limited thereto.

[0405] like Figure 61 As shown, substrate 1 has a main surface 11 and a back surface 15. The main surface 11 and the back surface 15 are spaced apart from each other in the z-direction. Furthermore, the main surface 11 and the back surface 15 face opposite sides in the z-direction. Both the main surface 11 and the back surface 15 of substrate 1 have a Miller index of (100). Figure 60 As shown, in the thermal printhead C10, the main surface 11 is opposite to the impression roller 69, and the back surface 15 is opposite to the heat dissipation component 66.

[0406] like Figure 61 As shown, the substrate 1 has a protrusion 12. The protrusion 12 protrudes from the main surface 11 in the z-direction. Figure 57 As shown, the protrusion 12 extends relatively long along the x-direction.

[0407] like Figure 62 As shown, the protrusion 12 has a top surface 121 and a pair of inclined surfaces 122. The top surface 121 is located away from the main surface 11 in the z-direction and is parallel to the main surface 11. The pair of inclined surfaces 122 are located at a distance from each other in the y-direction. The pair of inclined surfaces 122 are connected to the top surface 121 and the main surface 11. The pair of inclined surfaces 122 are inclined relative to the main surface 11 in such a way that they move closer to each other as they move from the main surface 11 to the top surface 121. The respective inclination angles α of the pair of inclined surfaces 122 relative to the main surface 11 are equal.

[0408] like Figure 57 , Figure 63 and Figure 64As shown, the substrate 1 has a pair of end faces 13 and a first face 14. The pair of end faces 13 face opposite to each other in the x-direction and are connected to the back surface 15. The first face 14 is located in the x-direction between at least one of the pair of end faces 13 and the protrusion 12. In the thermal printhead C10, the first face 14 includes a pair of separated regions 14A located on both sides of the protrusion 12. The surface roughness of the first face 14 is greater than that of the main face 11.

[0409] like Figure 64 As shown, the first surface 14 is located in the z-direction closer to the main surface 11 than the top surface 121 of the protrusion 12. Therefore, as Figure 65 As shown, the distance h1 in the z-direction from the main surface 11 to the first surface 14 is smaller than the distance h2 in the z-direction from the first surface 14 to the top surface 121. The first surface 14 is located between the main surface 11 and the top surface 121 in the z-direction. Therefore, the first surface 14 protrudes from the main surface 11 by only a distance h1 in the z-direction. The width b (the dimension in the y-direction) of the first surface 14 is smaller than the width B (the dimension in the y-direction of the lowest part of the protrusion 12) of the lowermost part of the protrusion 12.

[0410] Figure 67 and Figure 68 Thermal printheads C11 and C12 are shown as variations of thermal printhead C10. In each of thermal printheads C11 and C12, the structure of the first surface 14 is the same as that of thermal printhead C10 (see reference). Figure 65 )different.

[0411] like Figure 67 As shown, in the thermal printhead C11, the first surface 14 is on the same plane as the main surface 11. The width b of the first surface 14 is the same as the width B of the lowest part of the protrusion 12.

[0412] like Figure 68 As shown, in the thermal printhead C12, the first surface 14 is located between the main surface 11 and the back surface 15 in the z-direction. Therefore, the first surface 14 is recessed from the main surface 11 in the z-direction and reaches both ends of the substrate 1 in the y-direction. The width b of the first surface 14 is greater than the width B of the lowest part of the protrusion 12, and is equal to the dimension in the y-direction of the substrate 1.

[0413] The structure of the first surface 14 in thermal printheads C10, C11, and C12 is determined by the difference in the removal depth (z-direction dimension) of the protrusion 12. In the manufacturing method of thermal printhead C10 described later, the first surface 14 is formed by removing at least a portion of both ends of the protrusion 12 in the y-direction (see reference). Figures 71-73 The thermal printhead C10 represents the case where the removal depth of the protrusion 12 is the shallowest. On the other hand, the thermal printhead C12 represents the case where the removal depth of the protrusion 12 is the deepest.

[0414] like Figure 63 and Figure 66 As shown, a plurality of linear marks 141 extending along the y-direction are formed in the first surface 14. In the thermal printhead C10, at least any one of the plurality of linear marks 141 includes a portion extending from the main surface 11 (refer to) in the z-direction. Figure 66 The prominent part.

[0415] Insulating layer 21 Figure 62 The main surface 11 and protrusion 12 of the substrate 1 are shown. The substrate 1 is electrically insulated from the resistive layer 3 and the wiring layer 4 using an insulating layer 21. The insulating layer 21 is, for example, formed of silicon dioxide (SiO2) using tetraethyl orthosilicate (TEOS) as a raw material. An example of the thickness of the insulating layer 21 is 1 μm or more and 15 μm or less. Figure 64 As shown, the insulating layer 21 also covers the first surface 14 of the substrate 1.

[0416] Resistor layer 3 Figure 61 and Figure 62 The resistive layer 3 is formed on the main surface 11 and the protrusion 12 of the substrate 1. The resistive layer 3 is in contact with the insulating layer 21. Thus, in the thermal printhead C10, the insulating layer 21 is sandwiched between the substrate 1 and the resistive layer 3. The resistive layer 3 is formed, for example, of tantalum nitride (TaN). An example of the thickness of the resistive layer 3 is 0.02 μm or more and 0.1 μm or less.

[0417] like Figure 58 , Figure 59 and Figure 62 As shown, the resistive layer 3 includes a plurality of heating elements 31. In the resistive layer 3, the plurality of heating elements 31 are portions exposed from the wiring layer 4. The wiring layer 4 selectively supplies power to the plurality of heating elements 31, thereby locally heating the recording medium 68. The plurality of heating elements 31 are arranged in a configuration along the x-direction. Among the plurality of heating elements 31, two adjacent heating elements 31 in the x-direction are located at a distance from each other. In the thermal printhead C10, the plurality of heating elements 31 are formed above the top surface 121 of the protrusion 12 of the substrate 1. Therefore, viewed along the z-direction, the plurality of heating elements 31 overlap with the top surface 121. Figure 60 As shown, in the thermal printer 100, multiple heating elements 31 are opposite to the impression roller 69.

[0418] Wiring layer 4, as Figure 61 and Figure 62As shown, a wiring layer 4 is formed in contact with the resistive layer 3. In the thermal printhead C10, a wiring layer 4 is formed on the resistive layer 3. The wiring layer 4 constitutes a conductive path for energizing the plurality of heating elements 31 of the resistive layer 3. The resistivity of the wiring layer 4 is lower than that of the resistive layer 3. The wiring layer 4 is, for example, a metal layer made of copper (Cu). The thickness of the wiring layer 4 is, for example, 0.3 μm or more and 2.0 μm or less. Alternatively, the wiring layer 4 may be a structure consisting of two metal layers: a titanium (Ti) layer stacked on the resistive layer 3 and a copper layer stacked on the titanium layer. In this case, the thickness of the titanium layer is, for example, 0.1 μm or more and 0.2 μm or less.

[0419] like Figure 58 As shown, wiring layer 4 includes a common wiring 41 and multiple independent wirings 42. The common wiring 41 is located on one side (downstream side) in the y-direction relative to the multiple heating elements 31 of resistive layer 3. The multiple independent wirings 42 are located on the other side (upstream side) in the y-direction relative to the multiple heating elements 31. Figure 59 As shown, viewed along the z-direction, multiple regions of the resistive layer 3 sandwiched between the common wiring 41 and multiple independent wirings 42 are multiple heat-generating parts 31.

[0420] like Figure 58 and Figure 59 As shown, the common wiring 41 has a base 411 and a plurality of extensions 412. In the y-direction, the base 411 is located at the peripheral edge downstream of the main surface 11 of the substrate 1. The base 411 is a strip extending in the x-direction. Each of the plurality of extensions 412 is a strip extending in the y-direction from the end of the base 411 opposite to the protrusion 12 of the substrate 1 towards a plurality of heating elements 31. The plurality of extensions 412 are arranged in an arrangement along the x-direction. A portion of each of the plurality of extensions 412 is formed on one of the pair of inclined surfaces 122 of the substrate 1, on the downstream side in the y-direction. Therefore, a portion of the common wiring 41 is formed on the inclined surface 122 on one of the pair of inclined surfaces 122, on the side in the y-direction. In the common wiring 41, current flows from the base 411 to the plurality of heating elements 31 via the plurality of extensions 412.

[0421] like Figure 58 and Figure 59As shown, each of the plurality of independent wirings 42 is a strip extending from the peripheral edge of the upstream side of the main surface 11 of the substrate 1 towards the plurality of heating elements 31. The plurality of independent wirings 42 are arranged along the x-direction. A portion of each of the plurality of independent wirings 42 is formed on the opposite side (upstream side) of one of a pair of inclined surfaces 122 of the substrate 1 in the y-direction. In each of the plurality of independent wirings 42, current flows from any of the plurality of heating elements 31 upstream. Viewed along the z-direction, each of the plurality of heating elements 31 is sandwiched between any of the plurality of independent wirings 42 and any of the plurality of extensions 412 of a common wiring 41. Figure 58 and Figure 59 The structure of the wiring layer 4 and the plurality of heating elements 31 shown is an example. The structure of the wiring layer 4 and the plurality of heating elements 31 of the present invention is not limited to this. Figure 58 and Figure 59 The structure shown.

[0422] Protective layer 5 Figure 61 As shown, multiple heating elements 31 and wiring layer 4 cover the resistive layer 3. The protective layer 5 is electrically insulating. The protective layer 5 contains silicon. The protective layer 5 is, for example, composed of any one of silicon dioxide, silicon nitride (Si3N4), and silicon carbide (SiC). Alternatively, the protective layer 5 may be a laminate formed from multiple of these materials. The thickness of the protective layer 5 is, for example, 1.0 μm or more and 10 μm or less. In the thermal printer 100, the recording medium 68 is composed of... Figure 60 The embossing roller 69 shown presses against the area of ​​the protective layer 5 covering the multiple heating elements 31. For example... Figure 64 As shown, the protective layer 5 also covers the area of ​​the insulating layer 21 covering the first surface 14 of the substrate 1.

[0423] like Figure 61 As shown, the protective layer 5 has a first opening 51 and a second opening 52. Each of the first opening 51 and the second opening 52 is a strip extending along the x-direction. Each of the first opening 51 and the second opening 52 penetrates the protective layer 5 in the z-direction. The first opening 51 is located on the downstream side. The first opening 51 is formed to the downstreammost side of the substrate 1. Figure 61 (The middle refers to the left end of the substrate 1). Alternatively, it can be a structure in which a protective layer 5 is formed in a strip-like region located at the downstream side of the substrate 1 relative to the first opening 51. The base 411 of the common wiring 41 is exposed from the first opening 51. The second opening 52 is located on the upstream side. The second opening 52 is formed to the upstream side of the substrate 1 (…). Figure 61 (The middle refers to the right end of the substrate 1). Alternatively, it can be a structure in which a protective layer 5 is formed in a strip-like region located at the upstream side of the substrate 1 relative to the second opening 52 and extending along the x-direction. A portion of each of the plurality of individual wirings 42 is exposed from the second opening 52.

[0424] First substrate 61 Figure 60 As shown, it is supported by the downstream side of the substrate 1 and the heat dissipation component 66. The second substrate 62 is as follows. Figure 60 The structure is shown supported by the upstream side of substrate 1 and a first substrate 61. Each of the first substrate 61 and the second substrate 62 is, for example, an FPC (Flexible Printed Circuit) and is flexible. Figure 1 As shown, viewed along the z-direction, the first substrate 61 and the second substrate 62 are each rectangular in shape with the x-direction as their long side. Viewed along the z-direction, the area of ​​the first substrate 61 is larger than the area of ​​the second substrate 62. The first substrate 61 and the second substrate 62 are not two substrates like the thermal printhead C10; they can also be a single substrate integrated into one piece.

[0425] like Figure 1 and Figure 60 As shown, the first substrate 61 has an inner surface 611, an outer surface 612, and an opening 613. The inner surface 611 and the outer surface 612 face opposite sides in the z-direction. The inner surface 611 is opposite to the heat dissipation component 66. The outer surface 612 is opposite to the impression roller 69. The opening 613 extends through the first substrate 61 in the z-direction. The opening 613 is located on the upstream side of the substrate 1. The opening 613 is a space for accommodating a plurality of driving elements 65. Figure 60 As shown, the second substrate 62 is supported by the outer surface 612 of the first substrate 61. The second substrate 62 has a mounting surface 621. The mounting surface 621 faces the same side as the inner surface 611 in the z-direction. A portion of the mounting surface 621 is exposed through the opening 613.

[0426] First connection wiring 63, as shown Figure 61 As shown, it is disposed on the inner surface 611 of the first substrate 61. Figure 1 As shown, the first connecting cable 63 has a first wiring portion 631 and a pair of second wiring portions 632. The first wiring portion 631 extends along the x-direction. The upstream end of the first wiring portion 631 is connected to the base 411 of a common wiring 41 formed on the main surface 11 of the substrate 1. This connection is achieved using a conductive bonding material such as solder. Thus, the first connecting cable 63 is conductive to the common wiring 41. The pair of second wiring portions 632 are connected to both ends of the first wiring portion 631 in the x-direction. Each of the pair of second wiring portions 632 extends upstream from the first wiring portion 631. Figure 63 and Figure 65 As shown, a pair of second wiring portions 632 respectively cross a pair of separated regions 14A relative to the first surface 14 of the substrate 1. Figure 64As shown, a pair of second wiring portions 632 are opposite to the protective layer 5. The pair of second wiring portions 632 are connected to a connector mounted on the first substrate 61. Thus, power is supplied from the connector to the common wiring 41.

[0427] like Figure 60 As shown, the region of the first substrate 61 located upstream of the protrusion 12 is positioned closer to the back surface 15 of the substrate 1 in the z-direction compared to the region of the first substrate 61 located downstream of the protrusion 12. A pair of second wiring portions 632 disposed on the first substrate 61 (see reference) Figure 57 Together with the first substrate 61, it is flexible. Thus, in each of the pair of second wiring portions 632, in the portion of either of the pair of separation regions 14A that cross the first surface 14 along the y direction, the position in the z direction can be varied from the downstream side to the upstream side, so that the position is close to the back surface 15.

[0428] Multiple second connection wirings 64 such Figure 61 As shown, the mounting surface 621 is disposed on the first substrate 61. Figure 58 As shown, each of the plurality of second connection wirings 64 has a pad portion 641 and an extension portion 642. The pad portions 641 of the plurality of second connection wirings 64 are arranged in a staggered configuration relative to the x-direction. Specifically, the pad portions 641 of the plurality of second connection wirings 64 include two rows of pad portions 641 arranged respectively in the x-direction. In each of the two rows of pad portions 641, the plurality of pad portions 641 are arranged along the x-direction with equal spacing p (spacing p is the center-to-center distance between two adjacent pad portions 641 in the x-direction). In the two rows of pad portions 641, the row of pad portions 641 located on the upstream side and the row of pad portions 641 located on the downstream side are staggered in the x-direction by only half a distance of spacing p. The extension portion 642 is a strip-shaped portion extending downstream from the end of any of the pad portions 641 of the plurality of second connection wirings 64 that is opposite to the protrusion 12 of the substrate 1 in the y-direction. The downstream ends of the extensions 642 of the plurality of second connecting wires 64 are respectively connected to the plurality of individual wires 42. This connection is made using a conductive bonding material such as solder. Thus, the plurality of second connecting wires 64 are respectively conductive to the plurality of individual wires 42.

[0429] Multiple drive elements 65 such Figure 1 and Figure 60As shown, a mounting surface 621 is mounted on the second substrate 62. Each of the plurality of driving elements 65 is a semiconductor element constituting various circuits. Each of the plurality of driving elements 65 is mounted with a COF (Clip On Film) relative to several pad portions 641 of the plurality of second connection wirings 64, and several wirings (not shown) disposed on the mounting surface 621 and different from the plurality of second connection wirings 64. These wirings are connected to a connector. Thus, power for printing signals, control signals, and operation of the plurality of driving elements 65 is input from the connector to the plurality of driving elements 65 via the wirings. Based on these electrical signals, the plurality of driving elements 65 switch the connection between the plurality of individual wirings 42 connected via the plurality of second connection wirings 64 and the ground electrode (not shown) to be on or off. Moreover, power is supplied from the connector to the plurality of heating elements 31 of the resistive layer 3 via the first connection wirings 63 disposed on the first substrate 61. Thus, among the multiple heating elements 31, the connection between any of the multiple independent wirings 42 and the ground electrode makes the heating element 31 conductive and selectively heat up.

[0430] Heat dissipation component 66, etc. Figure 60 As shown, the back surface 15 of the substrate 1 faces the inner surface 611 of the first substrate 61. The back surface 15 is bonded to the heat dissipation member 66. The first substrate 61 is supported by the heat dissipation member 66. The first substrate 61 is fixed to the heat dissipation member 66 by fastening members such as screws. When the thermal printhead C10 is in use, a portion of the heat generated from the plurality of heating elements 31 of the resistive layer 3 is conducted to the heat dissipation member 66 via the substrate 1. The heat conducted to the heat dissipation member 66 is dissipated to the outside. The heat dissipation member 66 is formed, for example, of aluminum (Al).

[0431] based on Figures 69-80 An example of the manufacturing method of the thermal printhead C10 will be explained.

[0432] like Figure 69 and Figure 70 As shown, a main surface 11 and a protrusion 12 are formed on the substrate 81. Specifically, as Figure 69 As shown, a first mask layer 891 and a second mask layer 892 are formed covering a portion of a substrate 81. The substrate 81 is formed of a semiconductor material. The semiconductor material is, for example, a single crystal of silicon. The substrate 81 is a silicon wafer. In a direction orthogonal to the z-direction, a plurality of interconnected components corresponding to a plurality of substrates 1 respectively correspond to the substrate 81. The substrate 81 has a first surface 81A and a second surface 81B. The first surface 81A and the second surface 81B face opposite sides to each other in the z-direction. Both the first surface 81A and the second surface 81B of the substrate 81 have a Miller index of (100).

[0433] A first mask layer 891 is formed to cover a first surface 81A and a second surface 81B. The first mask layer 891 is formed of silicon dioxide. A second mask layer 892 is formed to cover the area of ​​the first mask layer 891 that covers the first surface 81A. The second mask layer 892 is formed of silicon nitride. The first mask layer 891 and the second mask layer 892 are formed by a first process described later. Figure 69 As shown, a first mask layer 891 covering a portion of the first surface 81A and a second mask layer 892 covering the first mask layer 891 are formed through a second process described later. A mask opening 893 extending in the z-direction is formed in the first mask layer 891 and the second mask layer 892 covering the first mask layer 891.

[0434] During the formation of the first mask layer 891 and the second mask layer 892, firstly, a thin film of silicon dioxide covering the first surface 81A and the second surface 81B is formed using thermal oxidation. Next, a thin film of silicon nitride covering the area of ​​the first mask layer 891 covering the first surface 81A is formed using thermal CVD (Chemical Vapor Deposition). This is the first process. Next, as a second process, a portion of the area of ​​the silicon dioxide thin film covering the first surface 81A and a portion of the silicon nitride thin film covering that area are removed using photolithography patterning and reactive ion etching (RIE). Thus, as... Figure 69 As shown, a first mask layer 891 and a second mask layer 892 are formed, and a mask opening 893 is formed in the first mask layer 891 covering a portion of the first surface 81A and the second mask layer 892 covering the first mask layer 891.

[0435] As another method for the first step, a method can also be used to form a thin film of silicon nitride covering the first surface 81A and the second surface 81B using thermal CVD. In this case, in the second step, a predetermined area in the first surface 81A covered by the first mask layer 891 and the area of ​​the first surface 81A exposed outside the first surface 81A, namely the mask opening 893, are formed by photolithography patterning and reactive ion etching.

[0436] Next, as Figure 70 As shown, a main surface 11 and a protrusion 12 are formed on a substrate 81. The main surface 11 and the protrusion 12 are formed by... Figure 69The area of ​​the first surface 81A exposed by the mask opening 893 shown is formed by wet etching using an aqueous solution of potassium hydroxide (KOH). This etching is anisotropic. Finally, the first mask layer 891 and the second mask layer 892 are removed by wet etching using hydrofluoric acid (HF). Through the above processes, a main surface 11 and a protrusion 12 are formed on the substrate 81. The second surface 81B of the substrate 81 becomes the back surface 15. The area of ​​the first surface 81A covered by the first mask layer 891 and the second mask layer 892 becomes the top surface 121 of the protrusion 12. The respective inclination angles α of the pair of inclined surfaces 122 of the protrusion 12 relative to the main surface 11 are equal. This is because the protrusion 12 is formed by anisotropic etching.

[0437] Next, as Figures 71-73 As shown, at least either end of the protrusion 12 in the x-direction of the substrate 81 is removed. In the illustrated example, both ends of the protrusion 12 are removed. Figure 71 As shown, in this process, by pressing the cutting blade 88, which rotates around the x-direction, against the protrusion 12, both ends of the protrusion 12 are removed. Figure 72 As shown, based on the x-direction dimension of the protrusion 12 to be removed, the cutting blade 88 is pressed against the protrusion 12 while being moved sequentially in the x-direction. Furthermore, when removing the end of the protrusion 12, a method can be used where the cutting blade 88 creates multiple notches spaced apart from each other in the x-direction behind the protrusion 12, and the protrusion 12, separated by these notches, is removed by wet etching. After this process, as... Figure 73 As shown, a first surface 14 is formed on the substrate 81. A plurality of linear marks 141 extending along the y-direction are formed on the first surface 14. In the substrate 1, the surface roughness of the first surface 14 becomes greater than that of the main surface 11.

[0438] exist Figure 71 and Figure 72 In the example shown, the thickness (dimension in the x-direction) of the cutting blade 88 is constant along the z-direction. Alternatively, a cutting blade whose thickness gradually decreases towards the peripheral edge (i.e., closer to the main surface 11 of the substrate 81 in the z-direction) can be used. In this case, the shape of the removed portion of the protrusion 12 (shape viewed along the y-direction) is as follows. Figure 71 It becomes a trapezoidal shape (lower base wall, upper base shorter). Therefore, Figure 64 The end face of the protrusion 12 shown facing the x direction ( Figure 64 The end face facing right becomes inclined to the lower right from the top face 121 towards the main face 11.

[0439] Next, as Figure 74As shown, an insulating layer 21 is formed covering the main surface 11 and the protrusion 12 of the substrate 81. The insulating layer 21 is a layer formed by stacking multiple thin films of silicon dioxide. Each thin film can be formed, for example, using tetraethyl orthosilicate (TEOS) as a raw material gas by plasma CVD.

[0440] Next, as Figures 75-77 The resistive layer 3 and wiring layer 4 are shown. The resistive layer 3 includes a plurality of heating elements 31 arranged in the x-direction. The wiring layer 4 is electrically connected to the plurality of heating elements 31. The process of forming the wiring layer 4 includes the process of forming a common wiring 41 and a plurality of individual wirings 42. In the substrate 81, the common wiring 41 is relative to... Figure 77 The multiple heating elements 31 of the resistive layer 3 shown are located on one side in the y-direction. In the substrate 81, multiple independent wirings 42 are positioned relative to... Figure 77 The multiple heating elements 31 shown are located on the other side in the y direction.

[0441] Specifically, such as Figure 75 As shown, a resistive film 82 is formed on the main surface 11 and the protrusion 12 of the substrate 81. The resistive film 82 is formed in such a way that it covers the entire surface of the insulating layer 21. The resistive film 82 is formed by laminating a thin film of tantalum nitride onto the insulating layer 21 using a sputtering method.

[0442] Next, as Figure 76 As shown, a conductive layer 83 is formed covering the entire surface of the resistive film 82. The conductive layer 83 is formed by repeatedly laminating a copper thin film onto the resistive film 82 using a sputtering method. Alternatively, when forming the conductive layer 83, a method can be used where a titanium thin film is laminated onto the resistive film 82 using a sputtering method, and then a copper thin film is laminated onto the titanium thin film using a sputtering method.

[0443] Next, as Figure 77 As shown, after photolithographic patterning of the conductive layer 83, a portion of the conductive layer 83 is removed. This removal is performed by wet etching using a mixed solution of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). As a result, a common wiring 41 and multiple individual wirings 42 are formed in contact with the resistive film 82. The wiring layer 4 is formed using this process. Furthermore, the area of ​​the resistive film 82 formed on the top surface 121 of the protrusion 12 of the substrate 81 is exposed from the wiring layer 4. Next, the portion of the resistive film 82 that is not needed in the thermal printhead C10 is removed. This removal is performed using reactive ion etching. As a result, a resistive layer 3 is formed on the main surface 11 and the protrusion 12 of the substrate 81. Multiple heating elements 31 are formed on the top surface 121 of the substrate 81.

[0444] Next, as Figure 78As shown, a protective layer 5 is formed covering the resistive layer 3, multiple heating elements 31, and the wiring layer 4. The protective layer 5 is formed by stacking thin films of silicon nitride using plasma CVD.

[0445] Next, as Figure 79 As shown, a first opening 51 and a second opening 52 extending in the z-direction are formed in the protective layer 5. The first opening 51 and the second opening 52 are formed by removing a portion of the protective layer 5 after photolithographic patterning. This removal is performed by reactive ion etching. As a result, the base 411 of the common wiring 41 is exposed from the first opening 51. A portion of each of the plurality of individual wirings 42 is exposed from the second opening 52.

[0446] Next, the substrate 81 is cut along the x and y directions, thereby dividing the substrate 81 into single pieces. This yields the substrate 1 for the thermal printhead C10. A pair of end faces 13 are formed on the substrate 1. Then, as... Figure 80 As shown, after a second substrate 62, which is provided with a plurality of second connecting wires 64, is supported by a first substrate 61, which is provided with a first connecting wire 63, the first wiring portion 631 of the first connecting wire 63 is connected to the base 411 of the common wiring 41. Furthermore, the plurality of second connecting wires 64 are connected to the plurality of individual wirings 42 respectively. These two connections are achieved using a conductive bonding material such as solder. Thus, a structure is formed in which the first substrate 61 and the second substrate 62 are supported by the substrate 1. Next, a plurality of driving elements 65 are mounted on the mounting surface 621 of the second substrate 62. Finally, the back surface 15 of the substrate 1 and the first substrate 61 are bonded to a heat dissipation member 66. Through the above processes, a thermal printhead C10 can be obtained.

[0447] Next, the function and effect of the thermal printhead C10 will be explained.

[0448] The substrate 1 of the thermal printhead C10 has a main surface 11, a protrusion 12, a pair of end faces 13, and a first surface 14. The first surface 14 is located between at least one of the pair of end faces 13 and the protrusion 12 in the x-direction, and in the z-direction, it is located closer to the main surface 11 than the top surface 121 of the protrusion 12. The thermal printhead C10 has a connecting wire (first connecting wire 63) that is conductive to the wiring layer 4 and crosses the first surface 14. By adopting this structure, even if the size of the substrate 1 is reduced, the conductive path for the wiring layer 4 (common wiring 41) can be set on the substrate 1. In this way, the thermal printhead C10 helps to achieve miniaturization.

[0449] The first surface 14 of the substrate 1 includes two separation regions 14A located at both ends of the protrusion 12. The connecting wires cross the separation regions 14A. As a result, the thermal printhead C10 can be miniaturized, and the cross-sectional area of ​​the conduction path for the common wiring 41 can be further enlarged, allowing more power to be supplied to the common wiring 41.

[0450] The thermal printhead C10 also includes a substrate (first substrate 61) with interconnecting wiring. The interconnecting wiring is connected to the common wiring 41. Therefore, in the manufacturing of the thermal printhead C10, it is not necessary to form the interconnecting wiring on the substrate 1. Furthermore, since the interconnecting wiring and the substrate are formed as an integral structure, it is possible to prevent the pattern of the interconnecting wiring from breaking due to external forces or other reasons.

[0451] In the thermal printhead C10, a portion of the common wiring 41 and portions of each of the multiple independent wirings 42 are formed on either of the pair of inclined surfaces 122 of the protrusion 12. Therefore, viewed along the z-direction, the dimensions of each of the multiple heat-generating elements 31 in the y-direction can be made smaller, and the contact area of ​​the recording medium 68 relative to the thermal printhead C10 can be further reduced. Thus, heat generation in the thermal printhead C10 can be suppressed, and the print quality on the recording medium 68 can be further improved.

[0452] In substrate 1, a pair of inclined surfaces 122 are inclined relative to the main surface 11 in such a way that they approach each other as they move from the main surface 11 toward the top surface 121. A shape like the protrusion 12 is formed as... Figure 66 In the manufacturing process of the thermal printhead C10 shown, the protrusions 12 are formed on the substrate 81 by anisotropic etching. This is because the substrate 81 is formed of a semiconductor material and the semiconductor material contains a single crystal of silicon.

[0453] The thermal printhead C10 has a protective layer 5 covering multiple heating elements 31 and wiring layer 4. Thus, the multiple heating elements 31 and wiring layer 4 are protected by the protective layer 5, and the frictional force on the recording medium 68 relative to the thermal printhead C10 is reduced.

[0454] The thermal printhead C10 also has a heat dissipation component 66. The back side 15 of the substrate 1 is attached to the heat dissipation component 66. Thus, when the thermal printhead C10 is in use, a portion of the heat generated by the multiple heat-generating parts 31 can be rapidly released to the outside via the substrate 1 and the heat dissipation component 66.

[0455] based on Figure 81 The thermal printhead C20 of the second embodiment of the third aspect has been described. Figure 81 In this drawing, for elements that are the same as or similar to the thermal printhead C10 described above, duplicate descriptions are omitted. Figure 81In the middle, for ease of understanding, the protective layer 5 is shown in the image.

[0456] In the thermal printhead C20, the structure of the first surface 14 of the substrate 1 and the structure of the first connecting wire 63 are different from those in the thermal printhead C10.

[0457] like Figure 81 As shown, the first surface 14 of the substrate 1 is located in the x-direction between either of the pair of end faces 13 and the protrusion 12. Therefore, in the thermal printhead C20, the first surface 14 has a structure that does not include the pair of separation regions 14A. Thus, the first connecting cable 63 has a first cable portion 631 and a second cable portion 632. The second cable portion 632 is connected only to the end of the first cable portion 631 located at the end of the first cable portion 631 in the x-direction.

[0458] Next, the function and effect of the thermal printhead C20 will be explained.

[0459] The substrate 1 of the thermal printhead C20 has a main surface 11, a protrusion 12, a pair of end faces 13, and a first surface 14. The first surface 14 is located between at least one of the pair of end faces 13 and the protrusion 12 in the x-direction, and in the z-direction, it is located closer to the main surface 11 than the top surface 121 of the protrusion 12. The thermal printhead C20 has a connecting wire (first connecting wire 63) that is conductive to the wiring layer 4 and crosses the first surface 14. Therefore, based on the thermal printhead C20, miniaturization of the thermal printhead can be achieved. Furthermore, by adopting the same structure as the thermal printhead C10, the thermal printhead C20 can achieve the same functional effect as the thermal printhead C10.

[0460] based on Figure 82 and Figure 83 The thermal printhead C30 of the third embodiment of the third aspect will be described. In these figures, elements that are the same as or similar to the thermal printhead C10 described above are labeled with the same reference numerals, and repeated descriptions are omitted. Figure 82 In the image, for ease of understanding, protective layer 5 is shown through the lens. Figure 83 In order to facilitate understanding, the insulating layer 21, the resistive layer 3, the wiring layer 4 (except for the base 411 of the common wiring 41) and the multiple second connection wirings 64 are further shown in the image.

[0461] The thermal printhead C30 differs from the thermal printhead C10 in that it has a structure with a first connecting wire 63 and a structure that also has a third connecting wire 67. Furthermore, the thermal printhead C30 does not have a first substrate 61.

[0462] like Figure 82 and Figure 83As shown, the first connecting wiring 63 includes two regions disposed apart from each other in the x-direction. These two regions are respectively connected to the two ends in the x-direction of the base 411 of the common wiring 41. Thus, the first connecting wiring 63 is conductive to the common wiring 41. The first connecting wiring 63 is formed together with the wiring layer 4 on the main surface 11 of the substrate 1. Therefore, the first connecting wiring 63 is made of the same metal layer as the metal layer constituting the wiring layer 4. The first connecting wiring 63 extends upstream from the base 411 and crosses a pair of separated regions 14A of the first surface 14 of the substrate 1.

[0463] like Figure 82 and Figure 83 As shown, the third connection cable 67 includes two regions spaced apart from each other in the x-direction. The third connection cable 67 is disposed on the mounting surface 621 of the second substrate 62. Each of the two regions of the third connection cable 67 extends along the y-direction. The downstream end of the third connection cable 67 is connected to the first connection cable 63. Thus, the third connection cable 67 is connected to the common cable 41 via the first connection cable 63. The third connection cable 67 is connected to a connector. Power is supplied to the common cable 41 via this connector.

[0464] Next, the function and effect of the C30 thermal printhead will be explained.

[0465] The substrate 1 of the thermal printhead C30 has a main surface 11, a protrusion 12, a pair of end faces 13, and a first surface 14. The first surface 14 is located in the x-direction between at least one of the pair of end faces 13 and the protrusion 12, and in the z-direction is located closer to the main surface 11 than the top surface 121 of the protrusion 12. The thermal printhead C30 has a connecting wire (first connecting wire 63) that is conductive to the wiring layer 4 and crosses the first surface 14. Therefore, miniaturization can also be achieved with the thermal printhead C30. Furthermore, by adopting the same structure as the thermal printhead C10, the thermal printhead C30 can achieve the same functional effect as the thermal printhead C10.

[0466] In the thermal printhead C30, the connecting wires are formed together with the wiring layer 4 on the main surface 11 of the substrate 1. Therefore, a substrate (first substrate 61) for configuring the connecting wires is not required. This allows for a further reduction in the y-direction dimension of the thermal printhead C30.

[0467] based on Figure 84 and Figure 85 The thermal printhead C40 of the fourth embodiment, which relates to the third side, will be described. In these figures, elements that are the same as or similar to the thermal printhead C10 described above are labeled with the same reference numerals, and repeated descriptions are omitted.

[0468] In the thermal printhead C40, the structure of the protrusion 12 of the substrate 1 and the structure of the multiple heating parts 31 of the resistive layer 3 are different from those in the thermal printhead C10.

[0469] like Figure 84 and Figure 85 As shown, the protrusion 12 has a pair of inclined surfaces 122, each including a first inclined surface 122A and a second inclined surface 122B. The first inclined surface 122A is connected to the main surface 11 of the substrate 1. The second inclined surface 122B is connected to the top surface 121 of the protrusion 12 and the first inclined surface 122A. In each of the pair of inclined surfaces 122, the inclination angle α2 of the second inclined surface 122B relative to the main surface 11 is smaller than the inclination angle α1 of the first inclined surface 122A relative to the main surface 11. Such a pair of inclined surfaces 122 are involved in the manufacturing of the thermal printhead C10. Figure 70 The process shown is the same as Figure 74 Between the processes shown, wet etching using an aqueous solution of tetramethylammonium hydroxide (TMAH) is performed at and near the boundary 123 between the top surface 121 and a pair of inclined surfaces 122.

[0470] like Figure 85 As shown, the plurality of heating elements 31 of the resistive layer 3 are formed in the following manner: First, the plurality of heating elements 31 are formed on the top surface 121 of the protrusion 12. Second, the plurality of heating elements 31 are formed across the top surface 121 and the second inclined surface 122B of the pair of inclined surfaces 122 of the protrusion 12 located on the downstream side. Third, the plurality of heating elements 31 are formed across the top surface 121, the second inclined surface 122B of the pair of inclined surfaces 122 located on the downstream side, and the first inclined surface 122A of the inclined surface 122. Fourth, the plurality of heating elements 31 are formed across the second inclined surface 122B and the first inclined surface 122A of the pair of inclined surfaces 122 located on the downstream side. In summary, the plurality of heating elements 31 are formed on at least one of the top surface 121 and the pair of inclined surfaces 122.

[0471] Next, the function and effect of the C40 thermal printhead will be explained.

[0472] The substrate 1 of the thermal printhead C40 has a main surface 11, a protrusion 12, a pair of end faces 13, and a first surface 14. The first surface 14 is located between at least one of the pair of end faces 13 and the protrusion 12 in the x-direction, and is located closer to the main surface 11 than the top surface 121 of the protrusion 12 in the z-direction. The thermal printhead C40 has a connecting wire (first connecting wire 63) that is conductive to the wiring layer 4 and crosses the first surface 14. Therefore, miniaturization can also be achieved with the thermal printhead C40. Furthermore, by adopting the same structure as the thermal printhead C10, the thermal printhead C40 can achieve the same functional effect as the thermal printhead C10.

[0473] In the thermal printhead C40, each of the pair of inclined surfaces 122 of the protrusion 12 includes a first inclined surface 122A and a second inclined surface 122B. The first inclined surface 122A is connected to the main surface 11 of the substrate 1. The second inclined surface 122B is connected to the top surface 121 of the protrusion 12 and the first inclined surface 122A. In each of the pair of inclined surfaces 122, the inclination angle α2 of the second inclined surface 122B relative to the main surface 11 is smaller than the inclination angle α1 of the first inclined surface 122A relative to the main surface 11. By adopting this structure, the shape of a portion of the wiring layer 4 formed along the protrusion 12 becomes smoother. Moreover, in the wiring layer 4 formed along the protrusion 12, the occurrence of defects or breaks in the wiring pattern can be suppressed.

[0474] based on Figure 86 and Figure 87 The thermal printhead C50 of the fifth embodiment of the third aspect will be described. In these figures, elements having the same or similar designations as the thermal printhead C10 described above are omitted from repeated descriptions. Figure 86 The cross-sectional position represents the main part of the thermal printhead C10. Figure 61 The cross-sectional positions are the same.

[0475] The difference between thermal printhead C50 and thermal printhead C10 is that it also has a glaze layer 22.

[0476] Glaze layer 22 Figure 86 and Figure 87 As shown, it is located between the top surface 121 of the protrusion 12 and the insulating layer 21. The glaze layer 22 is made of a glass-containing material, such as amorphous glass. The coefficient of linear expansion of the glaze layer 22 is the same as or substantially the same as the coefficient of linear expansion of the substrate 1. Figure 87 As shown, the glaze layer 22 protrudes in the z-direction toward the side facing the top surface 121. The dimension H of the glaze layer 22 in the z-direction is largest at the center of the glaze layer 22 in the y-direction.

[0477] Next, based on Figure 88 An example of the manufacturing method for the thermal printhead C50 will be explained.

[0478] Similar to the case of thermal printhead C10, at least either end of the protrusion 12 of substrate 81 in the x-direction is removed. Figures 71-73 After that, such as Figure 88 As shown, the glaze layer 22 is formed in contact with the top surface 121 of the protrusion 12 of the substrate 81. The glaze layer 22 is formed by supplying glaze material, which is a fluid, to the top surface 121 and then firing the glaze material. The glaze material is supplied, for example, by spraying the glaze material from a dispenser. The glaze material protects glass such as amorphous glass. The glaze material can also be coated multiple times. As another example of the method of supplying the glaze material, a method of printing the glaze material onto the top surface 121 using a screen printing machine can be used. After the glaze layer 22 is formed, similar to the case of the thermal printhead C10 described above, it is processed by... Figures 74-80 The same process shown can produce a thermal printhead C50.

[0479] Next, the function and effect of the C50 thermal printhead will be explained.

[0480] The substrate 1 of the thermal printhead C50 has a main surface 11, a protrusion 12, a pair of end faces 13, and a first surface 14. The first surface 14 is located between at least one of the pair of end faces 13 and the protrusion 12 in the x-direction, and is located in the z-direction closer to the main surface 11 than the top surface 121 of the protrusion 12. The thermal printhead C50 has a connecting wire (first connecting wire 63) that is conductive to the wiring layer 4 and crosses the first surface 14. Therefore, miniaturization can be achieved with the thermal printhead C50.

[0481] The thermal printhead C50 also has a glaze layer 22 located between the top surface 121 of the protrusion 12 and the insulating layer 21. The glaze layer 22 protrudes in the z-direction toward the side facing the top surface 121. By adopting this structure, the size of the protrusion 12 can be suppressed, and the contact area of ​​the recording medium 68 with respect to the thermal printhead C50 can be further reduced. Furthermore, the glaze layer 22 can effectively store heat dissipated from the multiple heating elements 31. Therefore, based on the thermal printhead C50, printing energy efficiency can be improved, and the printing quality to the recording medium 68 through the multiple heating elements 31 can be improved.

[0482] This invention is not limited to the embodiments described in the third aspect above. Various design changes can be made to the specific structures of each part of this invention. Embodiments of the third aspect of this invention include the structures described in the following appendices 1C to 21C.

[0483] Note 1C.

[0484] A thermal printhead comprising:

[0485] The substrate has a main surface facing the thickness direction, a pair of end surfaces spaced apart from each other in the main scanning direction, and a protrusion that protrudes from the main surface in the thickness direction and extends along the main scanning direction.

[0486] A resistive layer comprising a plurality of heating elements arranged in the main scanning direction, and formed on the main surface and the protrusion;

[0487] A wiring layer that is in contact with the resistive layer and is conductive to the plurality of heating elements; and

[0488] Connection wiring,

[0489] The aforementioned protrusion has a top surface parallel to the aforementioned main surface.

[0490] The aforementioned substrate has a first surface located between at least one of the pair of end faces and the protrusion in the main scanning direction, and located closer to the main surface than the top surface in the thickness direction.

[0491] The aforementioned connection wiring is configured to be conductive to the aforementioned wiring layer and span the aforementioned first surface.

[0492] Note 2C.

[0493] The thermal printhead described in Appendix 1C

[0494] The aforementioned protrusion has a pair of inclined surfaces that are connected to the aforementioned top surface and the aforementioned main surface and are spaced apart from each other in the sub-scanning direction.

[0495] Viewed along the aforementioned thickness direction, the aforementioned multiple heating elements overlap with the aforementioned top surface.

[0496] Note 3C.

[0497] Note 2C describes the thermal printhead.

[0498] The aforementioned wiring layer includes common wiring and multiple independent wiring.

[0499] The aforementioned common wiring is located on one side of the aforementioned sub-scanning direction relative to the aforementioned plurality of heating elements.

[0500] The aforementioned multiple independent wirings are located on the opposite side of the aforementioned multiple heating elements in the sub-scanning direction.

[0501] A portion of the aforementioned common wiring is formed on one of the aforementioned inclined surfaces located in the aforementioned sub-scanning direction.

[0502] A portion of each of the aforementioned individual wirings is formed on the inclined surface located on the other side of the aforementioned sub-scanning direction among the aforementioned pair of inclined surfaces.

[0503] The aforementioned connection wiring is connected to the aforementioned common wiring.

[0504] Note 4C.

[0505] Note 3C records of thermal printheads,

[0506] The first surface mentioned above includes a pair of separate regions located at both ends of the main scanning direction of the protrusion mentioned above.

[0507] The aforementioned connection wiring spans each of the aforementioned pair of separate regions.

[0508] Note 5C.

[0509] Note the thermal printhead as described in the 3C or 4C documentation.

[0510] The surface roughness of the first surface is greater than that of the main surface.

[0511] Note 6C.

[0512] Note 5C describes the thermal printhead.

[0513] A linear mark extending along the sub-scanning direction is formed on the first surface described above.

[0514] The aforementioned linear marks include portions that protrude from the aforementioned main surface in the aforementioned thickness direction.

[0515] Note 7C.

[0516] Note: Thermal printheads described in any of the following: 3C to 6C

[0517] The aforementioned pair of inclined surfaces are inclined in such a way that they move closer to each other as they move from the aforementioned main surface to the aforementioned top surface.

[0518] Note 8C.

[0519] Note 7C describes the thermal printhead.

[0520] Each of the aforementioned pair of inclined surfaces includes a first inclined surface connected to the aforementioned main surface, and a second inclined surface connected to the aforementioned top surface and the aforementioned first inclined surface.

[0521] The inclination angle of the second inclined surface relative to the main surface is smaller than the inclination angle of the first inclined surface relative to the main surface.

[0522] Note 9C.

[0523] Note 3C to 8C describes any of the thermal printheads.

[0524] The aforementioned substrate is made of semiconductor material.

[0525] The aforementioned semiconductor material is a single-crystal silicon material.

[0526] Note 10C.

[0527] Note 9C describes the thermal printhead.

[0528] It also has an insulating layer covering the main surface and the protrusion.

[0529] The resistive layer is in contact with the insulating layer.

[0530] Note 11C.

[0531] Note 10C describes the thermal printhead.

[0532] It also has a glaze layer located between the aforementioned top surface and the aforementioned insulating layer.

[0533] The aforementioned glaze layer protrudes in the direction of the aforementioned thickness towards the direction in which the aforementioned top surface faces.

[0534] Note 12C.

[0535] The thermal printhead described in Appendix 11C

[0536] The aforementioned glaze layer is composed of a material containing glass.

[0537] Note 13C.

[0538] Note 3C to 12C describes thermal printheads.

[0539] It also has a protective layer covering the aforementioned multiple heating elements and the aforementioned wiring layer.

[0540] Note 14C.

[0541] Note 13C describes the thermal printhead.

[0542] A portion of the aforementioned protective layer is located on the aforementioned first surface.

[0543] The aforementioned connection wiring is opposite to the aforementioned protective layer.

[0544] Note 15C.

[0545] Note 3C to 14C describes thermal printheads.

[0546] It also has a substrate configured with the aforementioned interconnecting wiring.

[0547] The aforementioned connection wiring is connected to the aforementioned common wiring.

[0548] Note 16C.

[0549] Note 15C describes the thermal printhead.

[0550] It also has heat dissipation components.

[0551] The substrate described above has a back side that faces the opposite side of the main surface in the thickness direction.

[0552] The aforementioned back side is bonded to the aforementioned heat dissipation component.

[0553] The aforementioned substrate is supported by the aforementioned heat dissipation component.

[0554] Note 17C.

[0555] A thermal printer comprising:

[0556] Note 3C to 16C describes a thermal printhead; and

[0557] Impression rollers are arranged opposite to the aforementioned multiple heating elements.

[0558] Note 18C.

[0559] A method for manufacturing a thermal printhead, comprising:

[0560] In the substrate preparation process, a main surface facing the thickness direction and a protrusion protruding from the main surface in the thickness direction and extending along the main scanning direction are formed on the substrate.

[0561] A removal process that removes at least one of the two ends of the aforementioned protrusion in the aforementioned main scanning direction;

[0562] The process of forming a resistive layer comprising a plurality of heating elements arranged in the main scanning direction on the aforementioned main surface and the aforementioned protrusion; and

[0563] The process of forming a wiring layer that is connected to the above-mentioned multiple heat-generating parts in contact with the above-mentioned resistive layer.

[0564] Note 19C.

[0565] Note 18C describes the manufacturing method of the thermal printhead.

[0566] The removal process includes pressing a cutting blade, which rotates about an axis parallel to the main scanning direction, onto the protrusion.

[0567] Note 20C.

[0568] The manufacturing method of the thermal printhead is described in Appendix 18C or 19C.

[0569] The aforementioned substrate is made of semiconductor material.

[0570] The aforementioned semiconductor material is a single-crystal silicon material.

[0571] Note 21C.

[0572] Appendix 20C describes the manufacturing method of the thermal printhead.

[0573] The aforementioned substrate preparation process includes an anisotropic etching process for forming the aforementioned main surface and the aforementioned protrusion.

[0574] [Explanation of reference numerals in the accompanying drawings of the third aspect of the embodiment]

[0575] C10, C20, C30, C40, C50: Thermal printheads

[0576] 1: Substrate 11: Main surface 12: Protrusion 121: Top surface

[0577] 122: Inclined surface 122A: First inclined surface

[0578] 122B: Second inclined surface; 123: Boundary; 13: End face

[0579] 14: First surface 14A: Separation area 141: Linear marks

[0580] 15: Back side; 21: Insulating layer; 22: Enamel layer

[0581] 3: Resistor layer; 31: Heating element; 4: Wiring layer

[0582] 41: Common wiring; 411: Base; 412: Extension.

[0583] 42: Independent wiring; 5: Protective layer; 51: First opening.

[0584] 52: Second opening; 61: First substrate; 611: Inner surface

[0585] 612: Outer surface; 613: Opening; 62: Second substrate

[0586] 621: Mounting surface 63: First connecting wiring

[0587] 631: First wiring section; 632: Second wiring section

[0588] 64: Second connection wiring; 641: Solder pad section

[0589] 642: Extension section; 65: Driving element; 66: Heat dissipation component

[0590] 67: Third-party connection wiring 68: Recording medium

[0591] 69: Impression roller; 81: Substrate; 81A: First side

[0592] 81B: Second surface; 82: Resistive film; 83: Conductive layer

[0593] 88: Cutting blade; 891: First mask layer

[0594] 892: Second mask layer; 893: Mask opening.

[0595] Next, embodiments of the fourth aspect of the present invention will be described with reference to... Figures 89-108 Please provide an explanation.

[0596] As described above, in the thermal printhead disclosed in Patent Document 2, a protrusion extending in the main scanning direction and protruding from the main surface of the substrate is formed on the main surface of the substrate. Furthermore, multiple heating elements are arranged on the protrusion along the main scanning direction. In the manufacture of such a thermal printhead, forming the protrusion requires a relatively long time. Therefore, one of the problems to be solved by the fourth aspect of the present invention is to provide a thermal printhead that can achieve both improved print quality and improved manufacturing efficiency.

[0597] based on Figures 89-94 The thermal printhead D10 of the first embodiment of the fourth aspect will be described. The thermal printhead D10 mainly includes a substrate 1, an insulating layer 2, a resistive layer 3, a wiring layer 4, a protective layer 5, and a cover layer 6. Furthermore, the thermal printhead D10 also includes a wiring substrate 71, a heat dissipation component 72, multiple drive elements 73, multiple first wires 74, multiple second wires 75, a sealing resin 76, and a connector 77. Figure 89 For ease of understanding, the protective layer 5 and the cover layer 6 are shown in perspective, and the illustrations of the multiple first conductors 74, multiple second conductors 75, and the sealing resin 76 are omitted. Figure 90 and Figure 91 In the image, for ease of understanding, the protective layer 5 and the covering layer 6 are shown in the image.

[0598] like Figure 92 As shown, the substrate 1 of the thermal printhead D10 is bonded to the heat dissipation component 72. A wiring substrate 71 is located adjacent to the substrate 1 in the y-direction. The wiring substrate 71 is fixed to the same heat dissipation component 72 as the substrate 1. On the substrate 1, a plurality of heating elements 31 (described later) forming part of the resistive layer 3 and arranged in the x-direction are formed. The plurality of heating elements 31 are selectively heated by a plurality of driving elements 73 mounted on the wiring substrate 71. The plurality of driving elements 73 are driven according to a print signal transmitted from the outside via a connector 77.

[0599] like Figure 92As shown, the thermal printhead D10 constitutes part of the thermal printer 100. As another element, the thermal printer 100 includes an impression roller 79. The impression roller 79 is configured to feed a recording medium 78, such as thermal paper. Printing occurs on the recording medium 78 while the impression roller 79 presses the recording medium 78 against multiple heating elements 31. As described in the third aspect, other non-roller-shaped mechanisms (e.g., flat or substantially flat pressing surfaces) may be used instead of the impression roller 79.

[0600] Substrate 1 as Figure 89 The image shows a strip extending in the x-direction. The substrate 1 is made of a semiconductor material. This semiconductor material is, for example, a single crystal of silicon (Si).

[0601] like Figure 93 As shown, substrate 1 has a main surface 11, a back surface 12, an end surface 13, and a middle surface 14. The main surface 11 and the back surface 12 face opposite sides in the z-direction. Both the main surface 11 and the back surface 12 of substrate 1 have a Miller index of (100). The main surface 11 and the back surface 12 face opposite sides in the z-direction. Figure 92 As shown, in the thermal printhead D10, the back side 12 is opposite to the heat dissipation component 72.

[0602] like Figure 93 As shown, the end face 13 of the substrate 1 faces the y-direction. The end face 13 is connected to the back surface 12. The intermediate surface 14 is connected to the main surface 11 and the end face 13. The intermediate surface 14 includes an inclined region 14A that is inclined relative to the main surface 11. Figure 93 As shown, in the thermal printhead D10, the inclined region 14A corresponds to the entirety of the intermediate surface 14. (As...) Figure 93 and Figure 94 As shown, the inclined region 14A is inclined at an angle α relative to the main surface 11. The surface roughness of the end face 13 is greater than that of the intermediate face 14.

[0603] Insulating layer 2 as Figure 93 As shown, the main surface 11 and the intermediate surface 14 of the substrate 1 are covered. An insulating layer 2 is located between the substrate 1 and the resistive layer 3. Through the insulating layer 2, the substrate 1 is electrically insulated relative to the resistive layer 3 and the wiring layer 4. The insulating layer 2 is, for example, made of silicon dioxide (SiO2) using tetraethyl orthosilicate (TEOS) as a raw material. The thickness of the insulating layer 2 is, for example, 1 μm or more and 15 μm or less. The end face 13 of the substrate 1 is exposed from the insulating layer 2.

[0604] Resistor layer 3 Figure 93As shown, the resistive layer 3 is formed on the main surface 11 and the intermediate surface 14 of the substrate 1. Alternatively, the resistive layer 3 may be formed only on the intermediate surface 14. The resistive layer 3 is in contact with the insulating layer 2. The resistive layer 3 is, for example, made of tantalum nitride (TaN). The thickness of the resistive layer 3 is, for example, 0.02 μm or more and 0.1 μm or less. The end face 13 of the substrate 1 is exposed from the resistive layer 3. Figure 93 In the example shown, the entire end face 13 is not covered by the resistive layer 3. Furthermore, preferably, the front portion of the resistive layer 3 in the intermediate surface 14 (the downstream portion of a specific layer (in this case, the resistive layer 3)) is covered by the protective layer 5. In this case, the resistive layer 3, to which voltage is applied, is not exposed in the front end face of the thermal printhead D10 (the downstream face of the thermal printhead D10 that includes the end face 13). By employing this structure, safety during the use of the thermal printhead D10 can be ensured.

[0605] like Figure 90 , Figure 91 and Figure 93 As shown, the resistive layer 3 includes a plurality of heating elements 31. In the resistive layer 3, the plurality of heating elements 31 are portions exposed from the wiring layer 4. By selectively energizing the plurality of heating elements 31 from the wiring layer 4, the plurality of heating elements 31 locally heat the recording medium 78. The plurality of heating elements 31 are arranged in the x-direction. Two adjacent heating elements 31 in the x-direction are located separately from each other. Viewed along the z-direction, the plurality of heating elements 31 overlap with the inclined region 14A (intermediate surface 14) of the substrate 1. Figure 92 As shown, in the thermal printer 100, multiple heating elements 31 are opposite to the impression roller 79.

[0606] Wiring layer 4, as Figure 93 As shown, it is formed in contact with the resistive layer 3. The wiring layer 4 forms a conductive path for energizing the plurality of heating elements 31 of the resistive layer 3. The resistivity of the wiring layer 4 is lower than that of the resistive layer 3. The wiring layer 4 is, for example, a metal layer made of copper (Cu). The thickness of the wiring layer 4 is, for example, 0.3 μm or more and 2.0 μm or less. Alternatively, the wiring layer 4 may be a structure formed by two metal layers: a titanium (Ti) layer stacked on the resistive layer 3 and a copper layer stacked on the titanium layer. In this case, the thickness of the titanium layer is, for example, 0.1 μm or more and 0.2 μm or less. The wiring layer 4 is formed on the main surface 11 and the intermediate surface 14 of the substrate 1. The wiring layer 4 is located at a position away from the boundary 15 between the intermediate surface 14 and the end face 13 of the substrate 1. The end face 13 is exposed from the wiring layer 4. Figure 93In the example shown, the entire end face 13 is not covered by the wiring layer 4. Furthermore, the front end of the wiring layer 4 in the intermediate face 14 is covered by the protective layer 5. Thus, the wiring layer 4, to which voltage is applied, is configured to not be exposed in the front end face of the thermal printhead D10. By employing this structure, safety during the use of the thermal printhead D10 can be ensured.

[0607] In the thermal printhead D10, such as Figure 90 and Figure 91 As shown, wiring layer 4 includes a common wiring 41, a plurality of independent wirings 42, and a plurality of relay wirings 43. Each of them is connected to any of the plurality of heat-generating units 31. Each of the common wiring 41 and the plurality of independent wirings 42 includes a portion formed on the main surface 11 of the substrate 1 and a portion formed on the intermediate surface 14 of the substrate 1. The common wiring 41 and the plurality of independent wirings 42 are located on the side of the main surface 11 (upstream side in the y direction) relative to the plurality of heat-generating units 31 in the y direction. The plurality of relay wirings 43 are located on the opposite side of the common wiring 41 and the plurality of independent wirings 42 (downstream side in the y direction) relative to the plurality of heat-generating units 31 in the y direction. The plurality of relay wirings 43 are formed on the intermediate surface 14.

[0608] like Figure 90 and Figure 91 As shown, the common wiring 41 has a base 411 and a plurality of extensions 412. The base 411 is located upstream of the plurality of individual wirings 42 in the y-direction. The base 411 is a strip extending in the x-direction. The plurality of extensions 412 are strips extending from the downstream end of the base 411 in the y-direction towards the plurality of heating elements 31. The plurality of extensions 412 are arranged along the x-direction. A portion of each of the plurality of extensions 412 is formed on the intermediate surface 14 of the substrate 1. Each of the plurality of extensions 412 is conductive to any of the plurality of heating elements 31. In the common wiring 41, current flows from the base 411 through the plurality of extensions 412 to the plurality of heating elements 31.

[0609] like Figure 90 and Figure 91 As shown, each of the plurality of independent wirings 42 has a pad portion 421 and an extension portion 422. The pad portion 421 is located upstream in the y-direction among the plurality of independent wirings 42. The extension portion 422 is a strip extending from the pad portion 421 toward the plurality of heat-generating units 31. The extension portions 422 of the plurality of independent wirings 42 are arranged along the x-direction. A portion of the extension portion 422 is formed on the intermediate surface 14 of the substrate 1. The extension portion 422 is conductive to any of the plurality of heat-generating units 31. In the x-direction, the extension portion 422 is adjacent to any of the plurality of extension portions 412 of the common wiring 41. In each of the plurality of independent wirings 42, current flows from any of the plurality of heat-generating units 31 to the pad portion 421 via the extension portion 422.

[0610] like Figure 90 and Figure 91 As shown, each of the plurality of relay wirings 43 is connected to two adjacent heating elements 31 among the plurality of heating elements 31. One of these two heating elements 31 is connected to any one of the plurality of extensions 412 of the common wiring 41. The other heating element 31 is connected to any one of the extensions 422 of the plurality of independent wirings 42. Thus, each of the plurality of relay wirings 43 is connected to the common wiring 41 and any one of the plurality of independent wirings 42 via these two heating elements 31. In each of the plurality of relay wirings 43, current flows from one of the two heating elements 31 connected to any one of the plurality of extensions 412 of the common wiring 41 to the other of the two heating elements 31 connected to any one of the extensions 422 of the plurality of independent wirings 42. These two heating elements 31 correspond to a dot formed on the recording medium 78.

[0611] Protective layer 5, such as Figure 93 As shown, multiple heating elements 31 and wiring layer 4 cover the resistive layer 3. The protective layer 5 is electrically insulating. The protective layer 5 contains silicon. The protective layer 5 is, for example, composed of any one of silicon dioxide, silicon nitride (Si3N4), and silicon carbide (SiC). Alternatively, the protective layer 5 may be a laminate composed of multiple of these materials. The thickness of the protective layer 5 is, for example, 1.0 μm or more and 10 μm or less. In the thermal printer 100, the recording medium 78 is... Figure 92 The embossing roller 79 shown presses against the area of ​​the protective layer 5 covering the multiple heating elements 31. The end face 13 of the substrate 1 is exposed from the protective layer 5.

[0612] like Figure 93 As shown, a wiring opening 51 is provided in the protective layer 5. The wiring opening 51 penetrates the protective layer 5 in the z direction. A portion of the pad portion 421 of the plurality of independent wirings 42 and a portion of the extension portion 422 of the plurality of independent wirings 42 are exposed from the wiring opening 51.

[0613] Covering layer 6 Figure 93 The protective layer 5 is shown. Viewed along the z-direction, the protective layer 6 overlaps the heating element 31 of the resistive layer 3. The protective layer 6 is made of, for example, silicon carbide. The end face 13 of the substrate 1 is exposed from the protective layer 6.

[0614] Wiring board 71 Figure 92 As shown, it is located upstream in the y-direction relative to substrate 1. Figure 89As shown, viewed along the z-direction, multiple independent wirings 42 are located in the y-direction between multiple heat-generating parts 31 of the resistive layer 3 and the wiring substrate 71. Viewed along the z-direction, the area of ​​the wiring substrate 71 is larger than the area of ​​the substrate 1. Furthermore, viewed along the z-direction, the wiring substrate 71 has a rectangular shape with the x-direction as its long side. The wiring substrate 71 is, for example, a PCB substrate. Multiple driving elements 73 and connectors 77 are mounted on the wiring substrate 71.

[0615] Heat dissipation component 72, etc. Figure 92 As shown, it faces the back surface 12 of the substrate 1. The back surface 12 is joined to the heat dissipation component 72. The wiring substrate 71 is fixed to the heat dissipation component 72 by fastening components such as screws. When the thermal printhead D10 is in use, a portion of the heat generated from the plurality of heating elements 31 in the resistive layer 3 is conducted to the heat dissipation component 72 via the substrate 1. The heat conducted to the heat dissipation component 72 is dissipated to the outside. The heat dissipation component 72 is made of, for example, aluminum (Al).

[0616] Multiple drive elements 73 such Figure 89 and Figure 92 As shown, the wiring board 71 is mounted on a bare die bonding material (not shown) with electrical insulation. Each of the plurality of drive elements 73 is a semiconductor element constituting various circuits. Each of the plurality of drive elements 73 has one end of a plurality of first wires 74 and one end of a plurality of second wires 75 bonded to it. The other ends of the plurality of first wires 74 are respectively bonded to the pad portions 421 of the plurality of individual wirings 42. The other ends of the plurality of second wires 75 are bonded to wirings (not shown) disposed on the wiring board 71 and connected to the connector 77. Thus, printing signals, control signals, and voltages (including ground potential) that cause the plurality of drive elements 73 to operate are input from the outside to the plurality of drive elements 73 via the connector 77. The plurality of drive elements 73 selectively apply voltages to the plurality of individual wirings 42 based on these electrical signals. Thus, the plurality of heating elements 31 selectively heat up.

[0617] Sealing resin 76 Figure 92 As shown, the circuit covers a plurality of drive elements 73, a plurality of first wires 74, and a plurality of second wires 75, as well as portions of the substrate 1 and the wiring substrate 71. The sealing resin 76 is electrically insulating. The sealing resin 76 is, for example, a black and soft synthetic resin used as a filler. Alternatively, the sealing resin 76 may also be a black and hard synthetic resin.

[0618] Connector 77 Figure 89 and Figure 92As shown, it is mounted at one end of the wiring board 71 in the y-direction. The connector 77 is connected to the control unit (not shown) of the thermal printer 100. The connector 77 has multiple pins. A portion of these pins is connected to wiring (not shown) that engages with multiple second wires 75 in the wiring board 71. Another portion of these pins is connected to wiring (not shown) that is connected to the base 411 of the common wiring 41 in the wiring board 71. A printing voltage (including ground potential) applied to multiple heating elements 31 is supplied to the other portion of these pins.

[0619] Next, based on Figures 95-103 An example of the manufacturing method for the thermal printhead D10 will be explained.

[0620] like Figure 95 and Figure 96 As shown, a groove 813 is formed in the substrate 81.

[0621] Specifically, such as Figure 95 As shown, a first mask layer 891 covering a substrate 81 and a second mask layer 892 covering a portion of the first mask layer 891 are formed. The substrate 81 is made of a semiconductor material. This semiconductor material is, for example, a single crystal of silicon. The substrate 81 is a silicon wafer. A structure consisting of multiple interconnected regions corresponding to multiple substrates 1 in a direction orthogonal to the z-direction corresponds to the substrate 81. The substrate 81 has a main surface 811 and a back surface 812. The main surface 811 and the back surface 812 face opposite sides to each other in the z-direction. Both the main surface 811 and the back surface 812 of the substrate 81 are surfaces with a Miller index of (100). The first mask layer 891 is formed to cover the main surface 811 and the back surface 812. The first mask layer 891 is made of silicon dioxide. The second mask layer 892 is formed to cover a region of the first mask layer 891 covering the main surface 811. The second mask layer 892 is made of silicon nitride. In the region of the first mask layer 891 covering the main surface 811 and the region of the second mask layer 892 covering the same region, a mask opening 893 extending in the z direction is formed.

[0622] During the formation of the first mask layer 891 and the second mask layer 892, firstly, a thin film of silicon dioxide covering the main surface 811 and the back surface 812 is formed using thermal oxidation. Next, a thin film of silicon nitride covering the area of ​​the first mask layer 891 covering the main surface 811 is formed using thermal CVD (Chemical Vapor Deposition). Finally, a portion of the area of ​​the silicon dioxide film covering the main surface 811 and a portion of the silicon nitride film covering that area are removed using photolithography patterning and reactive ion etching (RIE). Thus, the first mask layer 891 and the second mask layer 892 are formed, and mask openings 893 are formed in the area of ​​the first mask layer 891 covering the main surface 811 and in the area of ​​the second mask layer 892 covering that area.

[0623] As the first mask layer 891, a thin film of silicon nitride covering the main surface 811 and the back surface 812 can also be formed by thermal CVD. In this case, a predetermined area covered by the first mask layer 891 in the main surface 811 and the area of ​​the main surface 811 exposed outside the area, namely the mask opening 893, are formed by photolithography patterning and reactive ion etching.

[0624] Next, as Figure 96 As shown, a groove 813 is formed in the substrate 81. The groove 813 is formed by... Figure 96 The area of ​​the main surface 811 of the substrate 81 exposed in the mask opening 893 is formed by wet etching using an aqueous solution of potassium hydroxide (KOH). This etching is anisotropic. Finally, the first mask layer 891 and the second mask layer 892 are removed by wet etching using hydrofluoric acid (HF). Through the above process, a groove 813 is formed in the substrate 81. The groove 813 is recessed from the main surface 811 in the z-direction and extends along the x-direction. The groove 813 is defined by a pair of inclined surfaces 814 and a bottom surface 815. The pair of inclined surfaces 814 are connected to the main surface 811 and are opposite to each other in the y-direction. The respective inclination angles α of the pair of inclined surfaces 814 relative to the main surface 811 are equal. The bottom surface 815 is located in the z-direction between the main surface 811 and the back surface 812 and is connected to the pair of inclined surfaces 814. In this way, a pair of inclined surfaces 814 and a bottom surface 815 are formed in the substrate 81 by anisotropic etching, thereby forming the groove 813.

[0625] After the groove 813 is formed on the substrate 81, a thin film of silicon dioxide covering the main surface 11 can also be formed using a thermal oxidation method. In the pad portions 421 where multiple independent wirings 42, each of which is respectively bonded with multiple first conductors 74, a metal layer is deposited. When this silicon dioxide thin film is deposited with a metal layer, it has the effect of suppressing abnormal growth of the metal layer.

[0626] Next, as Figure 97 An insulating layer 2 is shown forming a main surface 11, a pair of inclined surfaces 814, and a bottom surface 815 covering a substrate 81. The insulating layer 2 is formed by repeatedly laminating a thin film of silicon dioxide, formed using tetraethyl orthosilicate (TEOS) as a feed gas, onto the substrate 81 using plasma CVD.

[0627] Next, as Figures 98-100 The diagram shows the formation of a resistive layer 3 and a wiring layer 4. The resistive layer 3 includes a plurality of heating elements 31 arranged in the x-direction. The wiring layer 4 is electrically connected to the plurality of heating elements 31.

[0628] like Figure 98 As shown, a resistive film 82 is formed on the substrate 81. The resistive film 82 is formed in such a way that it covers the entire surface of the insulating layer 2. The resistive film 82 is formed by laminating a thin film of tantalum nitride onto the insulating layer 2 using a sputtering method.

[0629] Next, as Figure 99 The conductive layer 83 is formed covering the entire surface of the resistive film 82. The conductive layer 83 is formed by repeatedly laminating a copper thin film onto the resistive film 82 using a sputtering method. Alternatively, when forming the conductive layer 83, a method can be used where a titanium film is laminated onto the resistive film 82 using a sputtering method, and then a copper thin film is laminated onto the titanium film using a sputtering method.

[0630] Next, as Figure 100 As shown, after photolithographic patterning of the conductive layer 83, a portion of the conductive layer 83 is removed. This removal is performed using wet etching with a mixed solution of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). As a result, the wiring layer 4 is formed in contact with the resistive film 82. Furthermore, a plurality of heating portions 31 of the resistive layer 3 are formed on a pair of inclined surfaces 814 of the substrate 81.

[0631] Next, as Figure 101 As shown, a protective layer 5 is formed covering the resistive layer 3, multiple heating elements 31, and wiring layer 4. The protective layer 5 is formed by laminating a thin film of silicon nitride onto the multiple heating elements 31 and wiring layer 4 using plasma CVD. Furthermore, in this process, the protective layer 5 is formed... Figure 93 The wiring opening 51 is shown. The wiring opening 51 is formed by removing a portion of the protective layer 5 after photolithographic patterning of the protective layer 5. This removal is performed using reactive ion etching. Thus, a portion of a plurality of independent wirings 42 ( Figure 93The pad portions 421 of the plurality of individual wirings 42 and portions of the extensions 422 of the plurality of individual wirings 42 are exposed from the wiring opening 51. Each portion of the plurality of individual wirings 42 and the portion exposed from the wiring opening 51 is, for example, a pad portion 421 that is respectively bonded to a plurality of first wires 74 by wire bonding. In each portion of the plurality of individual wirings 42 exposed from the wiring opening 51 (including the pad portion 421), a metal layer such as a plating layer or gold layer may also be used.

[0632] Next, as Figure 102 The protective layer 6 is shown as forming the protective layer 5. The protective layer 6 is formed by laminating a thin film of silicon carbide onto the protective layer 5 using plasma CVD. In this process, viewed along the z-direction, the protective layer 6 is formed in a manner that overlaps with the plurality of heating elements 31 of the resistive layer 3.

[0633] Next, as Figure 103 As shown, the substrate 81 is cut in the z-direction. A cutting blade 88 containing abrasive particles is used when cutting the substrate 81. In this process, the groove 813 of the substrate 81 is cut in the y-direction. Through this process, the cut substrate 81 becomes the substrate 1, and a main surface 11, a back surface 12, an end surface 13, and a middle surface 14 are formed on the substrate 1. The main surface 11 corresponds to a portion of the main surface 811 of the substrate 81. The back surface 12 corresponds to a portion of the back surface 812 of the substrate 81. The end surface 13 corresponds to the cut surface of the substrate 81 in this process. The middle surface 14 is a portion of either of the pair of inclined surfaces 814 of the substrate 81. Therefore, through this process, the main portion of the thermal printhead D10 protecting the substrate 1 is obtained. The reason why the surface roughness of the end surface 13 is greater than that of the middle surface 14 is that the end surface 13 is the cut surface of the substrate 81 and is a processed surface containing processing marks based on abrasive particles, while the middle surface 14 is a processed surface formed by removing a portion of the substrate 81 through anisotropic etching.

[0634] In the process of cutting the substrate 81 in the z-direction, a laser can also be used. In this process, after forming cracks, grooves, or multiple bottomed holes arranged in a straight line at a predetermined interval on the main surface 811 of the substrate 81 using a laser, an external force is applied to the substrate 81 to cut it. In this process, an end face 13 with a surface roughness greater than that of the intermediate surface 14 is obtained.

[0635] Next, multiple drive elements 73 and connectors 77 are mounted on the wiring board 71. Then, the back surface 12 of the substrate 1 and the wiring board 71 are bonded to the heat dissipation component 72. Next, multiple first wires 74 and multiple second wires 75 are bonded to the wiring board 71. Finally, a sealing resin 76 covering the drive elements 73, the multiple first wires 74, and the multiple second wires 75 is formed on the substrate 1 and the wiring board 71. The thermal printhead D10 is obtained after these processes.

[0636] Next, based on Figure 104 The thermal printhead D11, a variant of the thermal printhead D10, will be explained.

[0637] like Figure 104 As shown, the structure of the intermediate surface 14 in the thermal printhead D11 differs from that in the thermal printhead D10. The intermediate surface 14 of the thermal printhead D11 includes an inclined region 14A and a protruding region 14B. The inclined region 14A is connected to the main surface 11. The protruding region 14B is connected to the end face 13 and the inclined region 14A. The protruding region 14B faces the same side as the main surface 11 in the z-direction. The protruding region 14B and the inclined region 14A are covered by the insulating layer 2. In the thermal printhead D11, the surface roughness of the end face 13 is greater than that of the intermediate surface 14. The intermediate surface 14 of the thermal printhead D11 is formed by cutting the substrate 81 in the z-direction during the manufacturing process of the thermal printhead D10 (see reference). Figure 103 In the process, the substrate 81 is cut off while retaining a portion of the bottom surface 815.

[0638] Next, based on Figure 105 A variation of the manufacturing method for the thermal printhead D10 will be explained.

[0639] The process of forming the groove 813 in the substrate 81 during the manufacturing process of the thermal printhead D10 (see reference) Figure 96 and Figure 97 Variations of ) are given as examples. Figure 105 The method shown is to form a groove 813 on a substrate 81. The groove 813 is formed on the substrate 81 by anisotropic etching using only a pair of inclined surfaces 814. The lower ends of the pair of inclined surfaces 814 are connected to each other. The groove 813 is defined only by the pair of inclined surfaces 814.

[0640] Next, the function and effect of the thermal printhead D10 will be explained.

[0641] The thermal printhead D10 includes an end face 13 facing the y-direction, an inclined region 14A inclined relative to the main face 11, and an intermediate surface 14 connected to the main face 11 and the end face 13. Viewed along the z-direction, the plurality of heating elements 31 of the resistive layer 3 overlap with the inclined region 14A. Therefore, when the thermal printhead D10 is used, the recording medium 78 can come into contact with a small area on the inclined region 14A. Thus, the heat generated by the plurality of heating elements 31 is efficiently conducted to the recording medium 78. Therefore, according to the thermal printhead D10, firstly, the amount of heat generated from the plurality of heating elements 31 required for printing on the recording medium 78 is relatively small, thereby reducing power consumption. Secondly, the print quality can be improved.

[0642] In the thermal printhead D10, the end face 13 of the substrate 1 is exposed from both the resistive layer 3 and the wiring layer 4. This structure of the end face 13 is achieved during the manufacturing of the thermal printhead D10 by having… Figure 95 and Figure 96 The process shown is forming the groove 813 on the substrate 81, and Figure 103 The process of cutting the substrate 81 in the z-direction shown can be achieved.

[0643] exist Figure 95 and Figure 96 In the process of forming the groove 813 on the substrate 81, a pair of inclined surfaces 814 are formed on the substrate 81 to form at least a portion of the groove 813. In the subsequent process, namely the process of forming the resistive layer 3 (see...),... Figures 98-100 In the thermal printhead D10, a resistive layer 3 is formed on a pair of inclined surfaces 814. Thus, the thermal printhead D10 includes a substrate 1 having an intermediate surface 14 containing an inclined region 14A, and can be configured such that a plurality of heating elements 31 overlap with the inclined region 14A when viewed along the z-direction.

[0644] To improve print quality, when a pair of inclined surfaces 814 are formed on the substrate 81, the formation time of a groove 813 recessed from the main surface 811 in the z-direction is shortened compared to the case where a protrusion protrudes from the main surface 811 of the substrate 81 in the z-direction. This is because the volume of the substrate 81 removed during the formation of the pair of inclined surfaces 814 is smaller when the groove 813 is formed compared to the case where the protrusion is formed. Furthermore, when the substrate 81 is cut in the z-direction, it is divided in the y-direction by the groove 813, and the number of main parts of the thermal printhead D10 manufactured becomes twice. Therefore, according to the manufacturing method of the thermal printhead D10, the manufacturing efficiency can be improved, and the end face 13 of the substrate 1 can be considered as a trace of the improved manufacturing efficiency of the thermal printhead D10. Based on the above process, both improved print quality and improved manufacturing efficiency of the thermal printhead can be achieved based on the thermal printhead D10.

[0645] The substrate 81 is made of semiconductor material (single crystal silicon). As a result, a pair of inclined surfaces 814 can be formed on the substrate 81 by anisotropic etching.

[0646] The substrate 1 is made of a semiconductor material (a single crystal of silicon). As a result, the thermal conductivity of the substrate 1 becomes relatively high (approximately 170 W / (m·K)), thus improving the heat dissipation of the thermal printhead D10. Furthermore, the exposed structure of the end face 13 of the substrate 1 contributes to the improvement in heat dissipation. In this case, the surface roughness of the end face 13 is greater than that of the middle surface 14 of the substrate 1, leading to an increase in the surface area of ​​the end face 13, thereby more effectively improving the heat dissipation of the thermal printhead D10. Moreover, the improved heat dissipation of the thermal printhead D10 contributes to the increase in printing speed.

[0647] The wiring layer 4 includes a portion formed on the intermediate surface 14 and is located at a position away from the boundary 15 between the intermediate surface 14 and the end face 13. Thus, in Figure 105 In the process of cutting the substrate 81 in the z-direction, the cutting blade 88 cuts the substrate 81 without contacting the wiring layer 4. Therefore, it is possible to prevent the wiring layer 4 from breaking in this process.

[0648] The thermal printhead D10 also has a protective layer 5 covering multiple heating elements 31 and wiring layer 4. As a result, the multiple heating elements 31 and wiring layer 4 are protected by the protective layer 5, and when the thermal printhead D10 is in use, the contact between the recording medium 78 and the thermal printhead D10 becomes smooth.

[0649] The thermal printhead D10 has a cover layer 6 that covers the protective layer 5. Viewed along the z-direction, the cover layer 6 overlaps with multiple heating elements 31. This configuration ensures that the recording medium 78 contacts the cover layer 6 during use of the thermal printhead D10. Therefore, wear on the protective layer 5 caused by the ejection of the recording medium 78 can be suppressed.

[0650] The thermal printhead D10 also has a heat dissipation component 72. The back side 12 of the substrate 1 is bonded to the heat dissipation component 72. Thus, when the thermal printhead D10 is in use, a portion of the heat generated from the multiple heat-generating parts 31 can be rapidly released to the outside via the substrate 1 and the heat dissipation component 72.

[0651] based on Figures 106-108 The thermal printhead D20 of the second embodiment of the fourth aspect of the present invention has been described. In these figures, the same reference numerals are used to label elements that are the same as or similar to the thermal printhead D10 described above, and repeated descriptions are omitted. Figure 106 For ease of understanding, the protective layer 5 and the cover layer 6 are shown in perspective, and the illustrations of the multiple first conductors 74, multiple second conductors 75, and the sealing resin 76 are omitted. Figure 107 and Figure 108 In the image, for ease of understanding, the protective layer 5 and the covering layer 6 are shown in the image.

[0652] In thermal printhead D20, the structure of wiring layer 4 is different from that of thermal printhead D10 described above.

[0653] like Figures 106-108 As shown, in the thermal printhead D20, the wiring layer 4 includes a common wiring 41 and a plurality of independent wirings 42, but does not include a plurality of relay wirings 43. The common wiring 41 is located on the side of the substrate 1 (downstream side in the y-direction) relative to the plurality of heating elements 31 of the resistive layer 3. The plurality of independent wirings 42 are located on the opposite side of the common wiring 41 relative to the plurality of heating elements 31 in the y-direction. A portion of the extension 422 of each of the common wiring 41 and the plurality of independent wirings 42 is formed on the intermediate surface 14 of the substrate 1.

[0654] like Figure 107 and Figure 108 As shown, the base 411 of the common wiring 41 is located at the furthest downstream position from the plurality of heating elements 31 in the y-direction. The plurality of extensions 412 of the common wiring 41 are strips extending from the upstream end of the base 411 in the y-direction towards the plurality of heating elements 31. The plurality of heating elements 31 are located between the common wiring 41 and the plurality of independent wirings 42 in the y-direction. Viewed along the z-direction, each of the plurality of heating elements 31 has a structure sandwiched in the y-direction by any one of the plurality of extensions 412 of the common wiring 41 and any one of the extensions 422 of the plurality of independent wirings 42.

[0655] Next, the function and effect of the thermal printhead D20 will be explained.

[0656] The thermal printhead D20 has an end face 13 facing the y-direction and an intermediate surface 14 including an inclined region 14A that is inclined relative to the main surface 11 and connected to the main surface 11 and the end face 13. Viewed along the z-direction, the plurality of heating elements 31 of the resistive layer 3 overlap with the inclined region 14A. The end face 13 is exposed from both the resistive layer 3 and the wiring layer 4. Therefore, based on the thermal printhead D20, both improved print quality and improved manufacturing efficiency of the thermal printhead can be achieved. Furthermore, by having the same structure as the thermal printhead D10, the corresponding functional effects can be achieved.

[0657] In the thermal printhead D20, multiple heating elements 31 are located in the y-direction between a common wiring 41 and multiple independent wirings 42. In other words, one heating element 31 corresponds to one dot formed on the recording medium 78. Therefore, the structure of the wiring layer 4 of the thermal printhead D10 (see reference...) Figure 91 In comparison, the number of independent wirings 42 per unit length along the x-direction can be increased. Therefore, the number of heating elements 31 corresponding to point 1 per unit length along the x-direction can be increased. Therefore, since the number of printing dots (dot density) per unit length along the x-direction involved in printing the recording medium 78 is increased, more precise printing can be performed on the recording medium 78.

[0658] The wiring layer 4 of each thermal printhead D10 and thermal printhead D20 is an example. The structure of the wiring layer 4 of the present invention is not limited to the structure of each thermal printhead D10 and thermal printhead D20.

[0659] This invention is not limited to the embodiments of the fourth aspect described above. Various design changes can be made to the specific structures of each part of this invention. Embodiments of the fourth aspect of this invention include the structures described in the following appendices 1D to 16D.

[0660] Postscript 1D.

[0661] A thermal printhead comprising:

[0662] The substrate has a main surface facing the thickness direction, an end surface facing the sub-scanning direction, and an intermediate surface that includes an inclined region that is inclined relative to the main surface and is connected to the main surface and the end surface.

[0663] A resistive layer comprising a plurality of heating elements arranged in the main scanning direction, and formed on the aforementioned intermediate surface; and

[0664] A wiring layer formed that is conductive to the aforementioned multiple heat-generating components and in contact with the aforementioned resistive layer.

[0665] Viewed along the aforementioned thickness direction, the aforementioned multiple heating elements overlap with the aforementioned inclined region.

[0666] The aforementioned end face is exposed from the aforementioned resistive layer and the aforementioned wiring layer.

[0667] Note 2D.

[0668] Note 1: Thermal printhead as recorded in 1D

[0669] The surface roughness of the aforementioned end face is greater than that of the aforementioned intermediate face.

[0670] Postscript: 3D.

[0671] Note the thermal printhead used for 1D or 2D recording.

[0672] The aforementioned wiring layer includes a portion formed on the aforementioned intermediate surface and is located at a position away from the boundary between the aforementioned intermediate surface and the aforementioned end face.

[0673] Note 4D.

[0674] Note: 3D recording thermal printing head,

[0675] The aforementioned wiring layers include common wiring and independent wiring.

[0676] Each of the aforementioned common wiring and the aforementioned independent wiring is connected to any one of the aforementioned multiple heat-generating components.

[0677] The aforementioned common wiring and the aforementioned independent wiring each include portions formed on the aforementioned intermediate surface.

[0678] Note 5D.

[0679] Note: 4D recording thermal printhead,

[0680] The aforementioned common wiring and the aforementioned independent wiring are located on the same side of the main surface relative to the aforementioned plurality of heating elements in the aforementioned sub-scanning direction, and are adjacent to each other in the aforementioned main scanning direction.

[0681] The aforementioned wiring layer includes a relay wiring located on the opposite side of the aforementioned common wiring and the aforementioned independent wiring relative to the aforementioned plurality of heat-generating units in the aforementioned sub-scanning direction.

[0682] The aforementioned trunk wiring is connected to the aforementioned common wiring and the aforementioned independent wiring via two adjacent heating elements among the aforementioned plurality of heating elements.

[0683] Note 6D.

[0684] Note: 4D recording thermal printhead,

[0685] The aforementioned common wiring is located on the side of the aforementioned end face relative to the aforementioned plurality of heating elements in the aforementioned sub-scanning direction.

[0686] The aforementioned independent wiring is located on the opposite side of the aforementioned common wiring relative to the aforementioned plurality of heating elements in the aforementioned sub-scanning direction.

[0687] The aforementioned multiple heating elements are located between the aforementioned common wiring and the aforementioned independent wiring in the aforementioned sub-scanning direction.

[0688] Note 7D.

[0689] Note any of the thermal printheads described in 1D to 6D.

[0690] The aforementioned substrate is made of semiconductor material.

[0691] The aforementioned semiconductor materials include single-crystal silicon.

[0692] Note 8D.

[0693] Note 7: Thermal printhead as recorded.

[0694] It also includes an insulating layer covering the main surface and the intermediate surface.

[0695] The insulating layer is located between the substrate and the resistive layer.

[0696] The aforementioned end face is exposed from the aforementioned insulating layer.

[0697] Note 9D.

[0698] Note any of the thermal printheads described in 1D to 8D.

[0699] It also includes a protective layer covering the aforementioned multiple heat-generating components and the aforementioned wiring layer.

[0700] The aforementioned end face is exposed from the aforementioned protective layer.

[0701] Postscript 10D.

[0702] Note 9D describes the thermal printhead.

[0703] It also includes a covering layer that covers the aforementioned protective layer.

[0704] Viewed along the aforementioned thickness direction, the aforementioned covering layer overlaps with the aforementioned plurality of heating elements.

[0705] The aforementioned end face is exposed from the aforementioned covering layer.

[0706] Postscript 11D.

[0707] Note the thermal printhead described in any of the entries from 1D to 10D.

[0708] It also includes heat dissipation components,

[0709] The substrate described above has a back side that faces the opposite side of the main surface in the thickness direction.

[0710] The aforementioned back surface is joined to the aforementioned heat dissipation component.

[0711] Note 12D.

[0712] A method for manufacturing a thermal printhead, comprising:

[0713] A process of forming a groove in a substrate having a main surface facing the thickness direction, which is recessed from the main surface in the thickness direction and extends along the main scanning direction.

[0714] The process of forming a resistive layer comprising a plurality of heating elements arranged in the main scanning direction on the aforementioned substrate; and

[0715] The process of forming a wiring layer that is connected to the above-mentioned multiple heat-generating parts in contact with the above-mentioned resistive layer.

[0716] In the process of forming the aforementioned groove, a pair of inclined surfaces are formed on the aforementioned substrate, which are connected to the aforementioned main surface, are opposite to each other in the sub-scanning direction, and define at least a portion of the aforementioned groove.

[0717] In the process of forming the resistive layer, the resistive layer is formed on the pair of inclined surfaces.

[0718] After the process of forming the wiring layer, the process further includes cutting the substrate in the thickness direction in such a way that the groove is cut in the sub-scanning direction.

[0719] Postscript 13D.

[0720] Appendix 12D describes the manufacturing method of the thermal printhead.

[0721] The aforementioned substrate is made of semiconductor material.

[0722] The aforementioned semiconductor materials include single-crystal silicon materials.

[0723] In the process of forming the aforementioned groove, the pair of inclined surfaces are formed by anisotropic etching.

[0724] Postscript 14D.

[0725] Appendix 13D describes the manufacturing method of the thermal printhead.

[0726] After the process of forming the aforementioned groove and before the process of forming the aforementioned resistive layer, there is also a process of forming an insulating layer covering the aforementioned main surface and the aforementioned pair of inclined surfaces.

[0727] Postscript 15D.

[0728] The manufacturing method of the thermal printhead described in any of the appendices 12D to 14D.

[0729] After the process of forming the wiring layer and before the process of cutting the substrate, there is a process of forming a protective layer covering the plurality of heating elements and the wiring layer.

[0730] Note 16D.

[0731] Appendix 15D describes the manufacturing method of the thermal printhead.

[0732] After the step of forming the protective layer and before the step of cutting the substrate, there is a step of forming a cover layer that covers the protective layer.

[0733] In the process of forming the above-mentioned covering layer, when viewed along the above-mentioned thickness direction, the above-mentioned covering layer overlaps with the above-mentioned plurality of heating elements.

[0734] [Explanation of reference numerals in the drawings of the fourth aspect of the embodiment]

[0735] D10, D20: Thermal printhead 1: Substrate

[0736] 11: Main face 12: Back face 13: End face

[0737] 14: Mid-surface 14A: Inclined area 14B: Extended area

[0738] 15: Boundary 2: Insulating layer 3: Resistor layer

[0739] 31: Heating Unit; 4: Wiring Layer; 41: Common Wiring

[0740] 411: Base; 412: Extension; 42: Independent wiring

[0741] 421: Solder pad section; 422: Extension section; 43: Repeater wiring.

[0742] 5: Protective layer; 51: Wiring opening; 6: Covering layer

[0743] 71: Wiring board; 72: Heat dissipation component; 73: Drive element

[0744] 74: First conductor; 75: Second conductor; 76: Sealing resin

[0745] 77: Connector; 78: Recording medium

[0746] 79: Impression roller; 81: Substrate

[0747] 811: Main side; 812: Back side; 813: Groove.

[0748] 814: Inclined surface; 815: Bottom surface; 82: Resistor film

[0749] 83: Conductive layer; 88: Cutting blade

[0750] 891: First mask layer; 892: Second mask layer

[0751] 893: Mask opening α: Inclination angle.

Claims

1. A thermal printhead, characterized in that, include: A semiconductor substrate having a main surface and a back surface spaced apart from each other in the thickness direction, and having a first through portion extending from the main surface to the back surface; A resistive layer comprising a plurality of heating elements arranged in the main scanning direction and formed on the main surface; A first electrode is formed on the back side; A wiring layer formed on the resistive layer and connected to the plurality of heating elements; The first through wiring housed in the first through section; A plurality of second electrodes and a plurality of second through wirings are formed on the back side; and The first insulating layer covering the main surface, The wiring layer includes a common wiring located on a first side of the sub-scanning direction relative to the plurality of heating elements. The first through wiring is connected to the common wiring and the first electrode. The wiring layer includes multiple independent wirings located on the second side of the sub-scanning direction relative to the plurality of heating elements. The semiconductor substrate has a plurality of second through-parts extending from the main surface to the back surface, and located on the opposite side of the first through-parts relative to the plurality of heat-generating portions in the sub-scanning direction. The plurality of second through wirings are each independently housed in the plurality of second through sections. Each of the plurality of second through wirings is connected to any of the plurality of independent wirings and any of the plurality of second electrodes. The semiconductor substrate has a first inner peripheral surface and a plurality of second inner peripheral surfaces. The first inner peripheral surface is connected to the main surface and the back surface and defines a first through-portion. The second inner peripheral surfaces are connected to the main surface and the back surface and define each of the plurality of second through-portions. The first insulating layer contacts the resistive layer and covers the first inner circumferential surface and the plurality of second inner circumferential surfaces.

2. The thermal printhead as described in claim 1, characterized in that: The main surface includes a base surface and a convex surface projecting from the base surface in the thickness direction. The convex surface extends along the main scanning direction. The plurality of heating elements are formed on the convex surface.

3. The thermal printhead as described in claim 2, characterized in that: The convex surface includes: a top surface parallel to the base surface; and a pair of inclined surfaces connected to the top surface and the base surface and located apart from each other in the sub-scanning direction. The plurality of heating elements are formed on the top surface.

4. The thermal printhead as described in claim 3, characterized in that: A portion of the common wiring and a portion of each of the plurality of independent wirings are formed on either of the pair of inclined surfaces.

5. The thermal printhead as described in claim 4, characterized in that: The pair of inclined surfaces are inclined relative to the base surface in such a way that they move closer to each other as they move from the base surface to the top surface.

6. The thermal printhead as described in claim 5, characterized in that: Each of the pair of inclined surfaces includes: a first region connected to the base surface; and a second region connected to the top surface and the first region. The tilt angle of the second region relative to the base surface is smaller than the tilt angle of the first region relative to the base surface.

7. The thermal printhead as described in claim 2, characterized in that: The semiconductor substrate comprises a single crystal of silicon.

8. The thermal printhead as described in any one of claims 1 to 7, characterized in that: It also has a second insulating layer that covers the back side and is connected to the first insulating layer. The first electrode and the plurality of second electrodes are in contact with the second insulating layer.

9. The thermal printhead as described in claim 8, characterized in that: It also has a heat dissipation layer, which is located between the first electrode and the plurality of second electrodes in the sub-scanning direction and is formed in contact with the second insulating layer. Viewed along the thickness direction, the heat dissipation layer overlaps with the plurality of heat-generating components.

10. The thermal printhead as described in claim 9, characterized in that: It also has a wiring board opposite to the back side and engaged with the first electrode and a plurality of second electrodes. The wiring board has a heat sink that is bonded to the heat dissipation layer.

11. The thermal printhead as described in any one of claims 1 to 7, characterized in that: It also has a protective layer covering a portion of the main surface, the plurality of heating elements, and the wiring layer.

12. A method for manufacturing a thermal printhead, characterized in that, include: A process for forming a first recess from the main surface in the thickness direction of a substrate having a main surface facing the thickness direction and being made of semiconductor material; The process of forming a resistive layer comprising a plurality of heating elements arranged in the main scanning direction on the main surface and in the first recess; The process of forming a wiring layer on the resistive layer that is connected to the plurality of heating elements; A process of removing a portion of the substrate located on the side opposite to the main surface in the thickness direction; and In the process of forming an electrode on the substrate, the electrode is located on the opposite side of the wiring layer relative to the substrate in the thickness direction and is in communication with the wiring layer. The process of forming the wiring layer includes forming a common wiring on a first side relative to the plurality of heating elements in the sub-scanning direction, and a first through wiring housed in the first recess and connected to the common wiring. In the process of removing a portion of the substrate, the portion of the substrate is removed until a portion of the first through-wire is exposed from the substrate. The process of forming the electrode includes the process of forming a first electrode that is conductive to the common wiring. In the process of forming the first electrode, the first electrode is formed in such a way that the first electrode contacts the first through wiring.

13. The method for manufacturing a thermal printhead as described in claim 12, characterized in that: The method also includes a step of forming a plurality of second recesses between the step of forming the first recess and the step of forming the resistive layer, wherein the plurality of second recesses are recessed from the main surface of the substrate in the thickness direction and are located on the opposite side of the plurality of heating elements in the sub-scanning direction relative to the first recess. In the process of forming the resistive layer, a portion of the resistive layer is formed in the plurality of second recesses. The process of forming the wiring layer includes forming a plurality of independent wirings located on a second side of the plurality of heating elements in the sub-scanning direction, and a plurality of second through wirings respectively housed in the plurality of second recesses and respectively connected to the plurality of independent wirings. In the process of removing a portion of the substrate, the portion of the substrate is removed until a portion of the plurality of second through-wires is exposed from the substrate. The process of forming the electrodes includes the process of forming a plurality of second electrodes that are respectively connected to the plurality of independent wirings. In the process of forming the plurality of second electrodes, the plurality of second electrodes are formed in such a way that the plurality of second electrodes are in contact with the plurality of second through wirings respectively.

14. The method for manufacturing a thermal printhead as described in claim 13, characterized in that: The main surface includes a base surface and a convex surface projecting from the base surface in the thickness direction. Prior to the step of forming the first recess, there is a step of forming a protrusion on the substrate, the protrusion protruding from the base surface in the thickness direction and extending along the main scanning direction, and including the convex surface. In the process of forming the resistive layer, the plurality of heating elements are formed on the convex surface.

15. The method for manufacturing a thermal printhead as described in claim 14, characterized in that: The semiconductor material comprises single-crystal silicon.

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