Thermal printhead and method of manufacturing a thermal printhead
By designing a convex portion with an inclined surface structure on the substrate of the thermal printhead, the problem of sharp substrate ends is solved, improving print quality and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROHM CO LTD
- Filing Date
- 2022-03-28
- Publication Date
- 2026-06-12
AI Technical Summary
In existing thermal printheads, the protrusions on the substrate tend to become sharp at the ends in the main scanning direction, which may damage the recording medium.
A convex structure with inclined surfaces, including a top surface and multiple inclined surfaces, is formed on the substrate of the thermal printhead to avoid sharp ends. The main surface and the convex structure are formed by etching through a mask layer, and the angle and surface roughness of the inclined surfaces are controlled during the manufacturing process.
It effectively prevents the main scanning direction end of the substrate protrusion from becoming sharp, thus improving the printing quality and security of the recording medium.
Smart Images
Figure CN115214238B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a thermal printhead and a method for manufacturing the same. Background Technology
[0002] Patent Document 1 discloses a thermal printhead having a substrate made of silicon. The substrate of this thermal printhead has a main surface and a protrusion extending along the main scanning direction and protruding from the main surface. As in Patent Document 1... Figure 6 As shown, multiple heating elements are arranged along the main scanning direction above the protrusion. With this configuration, the recording medium can reliably contact the protrusion with the multiple heating elements, thus improving print quality. Furthermore, the substrate of this thermal printhead has the advantages of relatively high thermal conductivity and lower cost than substrates made of materials containing aluminum nitride. However, in this thermal printhead, the end face of the protrusion located at its end in the main scanning direction is abruptly perpendicular to the main surface. Therefore, the end of the protrusion in the main scanning direction is prone to becoming sharp. If this end becomes sharp, there is a concern that it may damage the recording medium; therefore, improvement is desired.
[0003] [Background Technical Documents]
[0004] [Patent Literature]
[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-166824 Summary of the Invention
[0006] [The problem the invention aims to solve]
[0007] In view of the above circumstances, the present disclosure aims to provide a thermal printhead and a method thereof capable of suppressing the sharpening of the ends of the protrusions of the substrate in the main scanning direction.
[0008] [Technical means to solve the problem]
[0009] The thermal printhead provided by the first aspect of this disclosure comprises: a substrate having a main surface facing the thickness direction and a protrusion protruding from the main surface and extending along the main scanning direction, and comprising a semiconductor material; a resistive layer comprising a plurality of heating elements arranged along the main scanning direction and located above the protrusion; and a wiring layer connected to the plurality of heating elements and grounded to the resistive layer; the protrusion having: a top surface facing the thickness direction and located away from the main surface; and a first inclined surface and a second inclined surface connected to the main surface and located at positions separated from each other in the sub-scanning direction, and inclined relative to the main surface; at least one of the two ends of the protrusion in the main scanning direction having a third inclined surface connected to the main surface and the first inclined surface, and a fourth inclined surface connected to the main surface and the second inclined surface, the third inclined surface being inclined relative to the main surface and the first inclined surface, and the fourth inclined surface being inclined relative to the main surface and the second inclined surface.
[0010] The second aspect of this disclosure provides a method for manufacturing a thermal printhead, comprising the following steps: forming a mask layer on the first and second surfaces of a substrate having a first surface and a second surface and comprising a semiconductor material, the first and second surfaces facing opposite sides in the thickness direction; forming a main surface and a protrusion on the substrate by anisotropic etching, the main surface facing the same direction as the first surface in the thickness direction and located between the first and second surfaces, the protrusion protruding from the main surface; removing the mask layer; and forming a resistive layer comprising a plurality of resistors arranged along the main scanning direction on the protrusion. A heating element; and a wiring layer grounded to the resistive layer to form a connection with the plurality of heating elements; the mask layer includes a first mask layer formed on the first surface and a second mask layer formed on the second surface, the first mask layer having: a covered portion extending along the main scanning direction and covering the first surface; two first openings located at a position spaced apart from the covered portion in the sub-scanning direction and extending along the main scanning direction; and a second opening located next to the end of the covered portion in the main scanning direction and connected to the two first openings; and the first surface is exposed from the two first openings and the second opening.
[0011] [The effects of the invention]
[0012] According to the thermal printhead and manufacturing method of the present disclosure, it is possible to suppress the tip of the protrusion of the substrate from becoming sharp in the main scanning direction.
[0013] Other features and advantages of this disclosure will become more apparent from the following detailed description based on the accompanying drawings. Attached Figure Description
[0014] Figure 1 This is a top view of the thermal printhead according to the first embodiment of this disclosure, through the protective layer.
[0015] Figure 2 yes Figure 1 A top view of the main parts of the thermal printhead shown.
[0016] Figure 3 yes Figure 2 A magnified view of a portion of the image.
[0017] Figure 4 It is along Figure 1 A cross-sectional view along line IV-IV.
[0018] Figure 5 yes Figure 1 The image shows a cross-sectional view of the main part of the thermal printhead.
[0019] Figure 6 yes Figure 5 A magnified view of a portion of the image.
[0020] Figure 7 yes Figure 1 The enlarged view further reveals the insulation layer, resistive layer, and wiring layer.
[0021] Figure 8 Is with Figure 7 The corresponding right-side view.
[0022] Figure 9 Is with Figure 7 The corresponding front view.
[0023] Figure 10 It is along Figure 7 A cross-sectional view along the XX line.
[0024] Figure 11 It is along Figure 7 A cross-sectional view along line XI-XI.
[0025] Figure 12 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0026] Figure 13 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0027] Figure 14 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0028] Figure 15 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0029] Figure 16 Yes Figure 1 A partially enlarged top view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0030] Figure 17 Yes Figure 1 A partially enlarged top view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0031] Figure 18 It is along Figure 17 A cross-sectional view of the XVIII-XVIII line.
[0032] Figure 19 Yes Figure 1 A partially enlarged top view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0033] Figure 20 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0034] Figure 21 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0035] Figure 22 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0036] Figure 23 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0037] Figure 24 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0038] Figure 25 Yes Figure 1 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0039] Figure 26 This is a cross-sectional view of the main part of the thermal printhead according to the second embodiment of this disclosure.
[0040] Figure 27 yes Figure 26 A magnified view of a portion of the image.
[0041] Figure 28 Yes Figure 26 A cross-sectional view illustrating the manufacturing steps of the main parts of the thermal printhead.
[0042] Figure 29 This is a cross-sectional view of the main part of the thermal printhead according to the third embodiment of this disclosure.
[0043] Figure 30 yes Figure 29 A magnified view of a portion of the image. Detailed Implementation
[0044] The embodiments used to implement this disclosure are described with reference to the accompanying drawings.
[0045] [First Embodiment]
[0046] based on Figures 1 to 11 The thermal printhead A10 of the first embodiment of this disclosure will be described. The thermal printhead A10 forms the main part of the thermal printer B10 described below. The thermal printhead A10 includes a main part and auxiliary parts. The main part of the thermal printhead A10 includes a substrate 1, an insulating layer 21, a resistive layer 3, a wiring layer 4, and a protective layer 5. The auxiliary parts of the thermal printhead A10 include a wiring substrate 71, a heat dissipation component 72, a plurality of driving elements 73, a plurality of first wires 74, a plurality of second wires 75, a sealing resin 76, and a connector 77. Here, in... Figure 1 For ease of understanding, the illustrations of the protective layer 5, and the plurality of first conductors 74, plurality of second conductors 75, and sealing resin 76 are omitted. Figure 2 and Figure 3 In the middle, for ease of understanding, through protective layer 5.
[0047] For ease of explanation, the main scanning direction of the thermal printhead A10 is referred to as the "x-direction". The secondary scanning direction of the thermal printhead A10 is referred to as the "y-direction". The thickness direction 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, "observing along the z-direction" means "observing along the thickness direction".
[0048] In the thermal printhead A10, such as Figure 4As shown, the substrate 1, which forms the main part of the thermal printhead A10, is bonded to the heat dissipation component 72. Furthermore, a wiring substrate 71 is located next to the substrate 1 in the y-direction. The wiring substrate 71, like the substrate 1, is fixed to the heat dissipation component 72. A plurality of heating elements 31 (details will be described below) are formed on the substrate 1, forming part of the resistive layer 3 and arranged along the x-direction. The plurality of heating elements 31 are selectively heated by a plurality of driving elements 73 mounted in 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.
[0049] Furthermore, the thermal printer B10 disclosed herein, such as Figure 4 As shown, the thermal printer B10 includes a thermal printhead A10 and a pressure roller 79. In the thermal printer B10, the pressure roller 79 is a roller-shaped mechanism that feeds recording media such as thermal paper. The pressure roller 79 presses the recording media against multiple heating elements 31, and these multiple heating elements 31 print on the recording media. In the thermal printer B10, a non-roller-shaped mechanism can be used instead of the pressure roller 79. This mechanism has a flat surface. Here, the flat surface includes a curved surface with a small curvature. In the thermal printer B10, the roller-shaped mechanism, including the pressure roller 79, is referred to as a "platen". Here, for ease of explanation, Figure 4 In this context, the supply side of the recording medium ( Figure 4 The right side of the middle (in the middle) is called the "upstream side". Figure 4 In the middle, the side where the recording medium is ejected ( Figure 4 The left side of the middle is called the "downstream side".
[0050] like Figure 1 As shown, substrate 1 is rectangular in shape, extending along the x-direction when viewed along the z-direction. Therefore, the x-direction corresponds to the long side direction of substrate 1, and the y-direction corresponds to the short side direction of substrate 1. Substrate 1 contains a semiconductor material. This semiconductor material comprises a single-crystal material composed of silicon (Si).
[0051] like Figure 5 As shown, substrate 1 has a main surface 11 and a back surface 12 facing opposite sides in the z-direction. The orientation of both the main surface 11 and the back surface 12, based on the crystal structure of substrate 1, is (100) plane. Figure 4 As shown, in the thermal printhead A10, the main surface 11 faces the pressure roller 79, and the back surface 12 faces the wiring substrate 71.
[0052] like Figure 5 As shown, substrate 1 has a protrusion 13. The protrusion 13 protrudes from the main surface 11 in the z-direction. As... Figure 1 and Figure 2 As shown, the protrusion 13 extends along the x-direction.
[0053] like Figure 5 and Figure 6 As shown, the protrusion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. The top surface 130, the first inclined surface 131, and the second inclined surface 132 extend along the x-direction. The top surface 130 faces the z-direction and is located away from the main surface 11. The top surface 130 is parallel to the main surface 11. The first inclined surface 131 and the second inclined surface 132 are connected to the main surface 11 and the top surface 130. The first inclined surface 131 and the second inclined surface 132 are located separately in the y-direction. The first inclined surface 131 is located on the upstream side. The second inclined surface 132 is located on the downstream side. The first inclined surface 131 and the second inclined surface 132 are inclined relative to the main surface 11. The first inclined surface 131 and the second inclined surface 132 move closer to each other from the main surface 11 towards the top surface 130. The inclination angle α of each of the first inclined surface 131 and the second inclined surface 132 relative to the main surface 11 is equal.
[0054] like Figure 7 As shown, at least one of the two ends of the protrusion 13 in the x-direction has a third inclined surface 133 and a fourth inclined surface 134 formed. In the thermal printhead A10, the third inclined surface 133 and the fourth inclined surface 134 are formed at each of the two ends. The third inclined surface 133 is connected to the main surface 11, the first inclined surface 131, and the top surface 130. The third inclined surface 133 is inclined relative to the main surface 11, the first inclined surface 131, and the top surface 130. The area of the third inclined surface 133 is smaller than the area of the first inclined surface 131. The fourth inclined surface 134 is connected to the main surface 11, the second inclined surface 132, and the top surface 130. The fourth inclined surface 134 is inclined relative to the main surface 11, the second inclined surface 132, and the top surface 130. The area of the fourth inclined surface 134 is smaller than the area of the second inclined surface 132.
[0055] like Figure 11 As shown, the third inclined surface 133 and the fourth inclined surface 134 move closer to each other from the main surface 11 toward the top surface 130. The inclination angle β1 of the third inclined surface 133 relative to the main surface 11 and the inclination angle β2 of the fourth inclined surface 134 relative to the main surface 11 are both greater than the inclination angle α.
[0056] like Figure 10 and Figure 11 As shown, the surface roughness of the third inclined surface 133 is greater than that of the first inclined surface 131. The surface roughness of the fourth inclined surface 134 is greater than that of the second inclined surface 132.
[0057] like Figure 7As shown, the periphery of the top surface 130 has a first edge 130A, a second edge 130B, a third edge 130C, and a fourth edge 130D. The first edge 130A forms the boundary between the top surface 130 and the first inclined surface 131. The second edge 130B forms the boundary between the top surface 130 and the second inclined surface 132. The second inclined surface 132 is parallel to the first inclined surface 131. The third edge 130C is connected to the first edge 130A and forms the boundary with the third inclined surface 133. The third inclined surface 133 is inclined relative to the first edge 130A in the x-direction. The fourth edge 130D is connected to the second edge 130B and forms the boundary with the fourth inclined surface 134. The fourth inclined surface 134 is inclined relative to the second edge 130B in the x-direction.
[0058] like Figure 7 As shown, the third edge 130C and the fourth edge 130D of the top surface 130 approach each other as the first edge 130A and the second edge 130B move away from the top surface 130 in the x direction. The end of the third edge 130C located on the opposite side of the first edge 130A is connected to the end of the fourth edge 130D located on the opposite side of the second edge 130B.
[0059] like Figure 7 and Figure 9 As shown, the third inclined surface 133 and the fourth inclined surface 134 are connected to each other in the y-direction. Figure 8 As shown, the edge 139 that forms the boundary between the third inclined surface 133 and the fourth inclined surface 134 is inclined relative to the main surface 11. Figure 7 As shown, when viewed along the z-direction, edge 139 is located further out in the x-direction than the top surface 130.
[0060] like Figure 5 and Figure 6 As shown, the insulating layer 21 covers the main surface 11 and the protrusion 13 of the substrate 1. Through the insulating layer 21, the substrate 1 is electrically insulated relative to the resistive layer 3 and the wiring layer 4. The insulating layer 21, for example, comprises silicon dioxide (SiO2) made from tetraethyl orthosilicate (TEOS). The thickness of the insulating layer 21 is, for example, 1 μm or more and 15 μm or less.
[0061] like Figure 5 and Figure 6 As shown, a resistive layer 3 is formed on the main surface 11 and the protrusion 13 of the substrate 1. The resistive layer 3 is in contact with the insulating layer 21. Thus, in the thermal printhead A10, the insulating layer 21 is sandwiched between the substrate 1 and the resistive layer 3. The resistive layer 3, for example, contains tantalum nitride (TaN). The thickness of the resistive layer 3 is, for example, 0.02 μm or more and 0.1 μm or less.
[0062] like Figure 2 , Figure 3 and Figure 6As 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. The plurality of heating elements 31 are arranged along the x-direction. Two adjacent heating elements 31 in the x-direction are located at mutually separated positions. The plurality of heating elements 31 are formed in contact with the insulating layer 21. In the thermal printhead A10, the plurality of heating elements 31 are formed on the top surface 130 of the protrusion 13 of the substrate 1. The plurality of heating elements 31 are located at the center of the top surface 130 in the y-direction. Figure 4 As shown, in the thermal printer B10, multiple heating elements 31 face the pressure roller 79.
[0063] like Figure 5 and Figure 6 As shown, the wiring layer 4 is formed in connection with the resistive layer 3. The wiring layer 4 forms conductive paths for energizing the plurality of heating elements 31 in the resistive layer 3. The resistivity of the wiring layer 4 is less than that of the resistive layer 3. The wiring layer 4 is, for example, a metal layer containing copper (Cu). The thickness of the wiring layer 4 is, for example, 0.3 μm to 2.0 μm. Alternatively, the wiring layer 4 may be configured to include two metal layers: a titanium (Ti) layer deposited on the resistive layer 3 and a copper layer deposited on the titanium layer. In this case, the thickness of the titanium layer is, for example, 0.1 μm to 0.2 μm. Figure 1 As shown, the wiring layer 4 is located at a position separated from the periphery of the main surface 11 of the substrate 1.
[0064] like Figure 2 As shown, wiring layer 4 includes a common wiring 41 and multiple individual wirings 42. The common wiring 41 is located downstream of the multiple heat-generating parts 31 of resistive layer 3. The multiple individual wirings 42 are located upstream of the multiple heat-generating parts 31. Figure 3 As shown, when viewed along the z-direction, multiple regions of the resistive layer 3 sandwiched between the common wiring 41 and multiple individual wirings 42 are multiple heat-generating parts 31.
[0065] like Figure 2 and Figure 3As 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 heating elements 31 of the resistive layer 3. The base 411 appears as a strip extending in the x-direction when viewed along the z-direction. The plurality of extensions 412 are strips extending from the ends of the base 411 toward the plurality of heating elements 31, the base 411 facing the protrusion 13 of the substrate 1 in the y-direction. 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 second inclined surface 132 of the protrusion 13. In the common wiring 41, current flows from the base 411 through the plurality of extensions 412 to the plurality of heating elements 31.
[0066] like Figure 2 and Figure 3 As 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 heating parts 31 of the resistive layer 3. The bases 421 of the multiple individual wirings 42 are arranged at equal intervals in a staggered configuration in the x-direction.
[0067] like Figure 2 and Figure 3 As shown, the extension 422 is a strip extending from the end of the base 421 toward a plurality of heating elements 31, the base 421 facing the protrusion 13 of the substrate 1 in the y-direction. The extensions 422 of a plurality of individual wirings 42 are arranged along the x-direction. Each extension 422 of a plurality of individual wirings 42 is formed on the first inclined surface 131 of the protrusion 13. In each of the plurality of individual wirings 42, current flows from any of the plurality of heating elements 31 through the extension 422 to the base 421. When viewed along the z-direction, the plurality of heating elements 31 are respectively sandwiched between any of the extensions 422 of the plurality of individual wirings 42 and any of the plurality of extensions 412 of the common wiring 41. Figure 2 and Figure 3 The wiring layer 4 and the plurality of heating elements 31 shown are examples. The configuration of the wiring layer 4 and the plurality of heating elements 31 in this disclosure is not limited to... Figure 2 and Figure 3 The structure shown.
[0068] like Figure 5 As shown, the protective layer 5 covers a portion of the main surface 11 of the substrate 1, multiple heating elements 31 of the resistive layer 3, and the wiring layer 4. The protective layer 5 is electrically insulating. The protective layer 5 contains silicon. For example, the protective layer 5 includes 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 to 10 μm. In the thermal printer B10, the recording medium is... Figure 4The paper pressing roller 79 shown presses against the area of the protective layer 5 covering multiple heating elements 31.
[0069] like Figure 5 As shown, the protective layer 5 has a wiring opening 51. The wiring opening 51 extends through the protective layer 5 in the z direction. A portion of the base 421 of each of the plurality of individual wirings 42 and a portion of the extension 422 of each of the plurality of individual wirings 42 are exposed from the wiring opening 51.
[0070] like Figure 4 As shown, the wiring substrate 71 is located next to substrate 1 in the y-direction. Figure 1 As shown, when viewed along the z-direction, multiple individual wirings 42 are located in the y-direction between multiple heat-generating parts 31 of the resistive layer 3 and the wiring substrate 71. When viewed along the z-direction, the area of the wiring substrate 71 is larger than the area of the substrate 1. Furthermore, when viewed along the z-direction, the wiring substrate 71 is rectangular with the x-direction as its long side. The wiring substrate 71 is, for example, a PCB (Printed Circuit Board) substrate. Multiple driving elements 73 and connectors 77 are mounted in the wiring substrate 71.
[0071] like Figure 4 As shown, the heat dissipation component 72 faces the back surface 12 of the substrate 1. The back surface 12 is bonded 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 A10 is used, 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 released to the outside. The heat dissipation component 72 contains, for example, aluminum (Al).
[0072] like Figure 1 and Figure 4 As shown, multiple driving elements 73 are mounted on a wiring substrate 71 via an electrically insulating patch material (not shown). Each driving element 73 is a semiconductor element configured with various circuits. Each driving element 73 has one end of a plurality of first wires 74 and one end of a plurality of second wires 75 attached to it. The other ends of the plurality of first wires 74 are individually attached to the base 421 of a plurality of individual wirings 42. The other ends of the plurality of second wires 75 are attached to wirings (not shown), which are disposed in the wiring substrate 71 and are connected to a connector 77. Thus, printing signals, control signals, and voltages supplied to the plurality of heating elements 31 of the resistive layer 3 are input from the outside to the multiple driving elements 73 via the connector 77. Based on these electrical signals, the multiple driving elements 73 selectively apply voltages to the plurality of individual wirings 42. This causes the plurality of heating elements 31 to selectively heat up.
[0073] like Figure 4As shown, the sealing resin 76 covers a plurality of drive elements 73, a plurality of first wires 74, a plurality of second wires 75, and a portion of each 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 an underfill adhesive. Alternatively, the sealing resin 76 may be a black and hard synthetic resin.
[0074] like Figure 1 and Figure 4 As shown, connector 77 is mounted on one end of wiring substrate 71 in the y-direction. Connector 77 is connected to thermal printer B10. Connector 77 has multiple pins (not shown). A portion of these pins is connected to wiring (not shown) in wiring substrate 71 to which multiple second wires 75 are bonded. Furthermore, another portion of these pins is connected to wiring (not shown) in wiring substrate 71 to which the base 411 of common wiring 41 is connected.
[0075] Next, based on Figures 12-25 An example of the manufacturing method for the thermal printhead A10 will be described here. Figures 12-15 ,and Figures 20-25 The cross-sectional position represents the main part of the thermal printhead A10. Figure 5 The cross-sectional positions are the same.
[0076] First of all Figures 12-14 As shown, a mask layer 89 is formed on a substrate 81. The substrate 81 contains a semiconductor material. The semiconductor material contains a single-crystal material composed of silicon. The substrate 81 is a silicon wafer. A portion formed by connecting multiple regions corresponding to 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 in the z-direction. The orientation of the first surface 81A and the second surface 81B based on the crystal structure of the substrate 81 is both (100) plane. The mask layer 89 includes a first mask layer 891 formed on the first surface 81A and a second mask layer 892 formed on the second surface 81B.
[0077] First, such as Figure 12 As shown, a second mask layer 892 is formed. To form the second mask layer 892, either a silicon nitride film or a silicon dioxide film covering the entire surface of the substrate 81 is formed by reduced-pressure CVD (Chemical Vapor Deposition). Then, this film covering the first surface 81A of the substrate 81 is removed by wet etching with hydrofluoric acid (HF). Thus, the second mask layer 892 is formed.
[0078] Next, as Figure 13 and Figure 14As shown, the first mask layer 891 is formed. When forming the first mask layer 891, as follows... Figure 13 As shown, either a silicon nitride film or a silicon dioxide film covering the entire first surface 81A of the substrate 81 is formed by plasma CVD. The temperature at which the film covering the substrate 81 is formed by plasma CVD is lower than the temperature at which the film covering the substrate 81 is formed by depressurized CVD. Then, as... Figure 14 As shown, a portion of the thin film covering the first surface 81A is removed by photolithographic patterning and reactive ion etching (RIE). This forms the first mask layer 891.
[0079] Figure 16 The diagram shows the state after the first mask layer 891 is formed on the first surface 81A of the substrate 81. (As shown) Figure 16 As shown, the first mask layer 891 has a covered portion 891A, two first openings 891B, and a second opening 891C. The covered portion 891A extends along the x-direction and covers the first surface 81A. The two first openings 891B are located at a position spaced apart from the covered portion 891A in the y-direction and extend along the x-direction. The second opening 891C is located next to the x-direction end of the covered portion 891A and is connected to the two first openings 891B. The first surface 81A is exposed through the two first openings 891B and the second opening 891C.
[0080] Next, as Figure 15 As shown, a main surface 11 and a protrusion 13 are formed on a substrate 81 by anisotropic etching, and then a mask layer 89 is removed. The main surface 11 faces in the same direction as the first surface 81A of the substrate 81 in the z-direction and is located between the first surface 81A and the second surface 81B of the substrate 81. The protrusion 13 protrudes from the main surface 11 in the z-direction and extends in the x-direction. Regarding the main surface 11 and the protrusion 13, the main surface 11 and the protrusion 13 are formed on the substrate 81 by anisotropic etching of the first surface 81A exposed from the two first openings 891B and the second opening 891C of the first mask layer 891. The etching solution used for anisotropic etching is, for example, an aqueous solution of potassium hydroxide (KOH). Then, the mask layer 89 is removed by wet etching using hydrofluoric acid. Through the above steps, the main surface 11 and the protrusion 13 are formed on the substrate 81. Furthermore, the second surface 81B becomes the back surface 12 of the substrate 1. The area of the first surface 81A covered by the cover portion 891A of the first mask layer 891 becomes the top surface 130 of the protrusion 13. Since the protrusion 13 is formed by anisotropic etching, the first inclined surface 131 and the second inclined surface 132 of the protrusion 13 each have an inclination angle α relative to the main surface 11 that are equal to each other.
[0081] Figure 17 and Figure 18The diagram shows the state of the substrate 81 after the main surface 11 and the protrusion 13 are formed on the substrate 81 by anisotropic etching and before the mask layer 89 is removed. The first inclined surface 131 and the second inclined surface 132 of the protrusion 13 are formed by anisotropic etching of the first surface 81A exposed from the two first openings 891B of the first mask layer 891. The third inclined surface 133 and the fourth inclined surface 134 of the protrusion 13 are formed by anisotropic etching of the first surface 81A exposed from the second opening 891C of the first mask layer 891. At this time, a portion of the covered portion 891A of the first mask layer 891 located above the third inclined surface 133 and the fourth inclined surface 134 is removed. Furthermore, a portion of the top surface 130 of the protrusion 13 is exposed from the first mask layer 891. This is because this portion has dissolved in the etching solution used for anisotropic etching. Silicon nitride and silicon dioxide films dissolve more readily in the etching solution during plasma CVD formation than during depressurized CVD formation. Therefore, the first mask layer 891 dissolves more readily in the etching solution than the second mask layer 892. Figure 18 As shown, the surface roughness of the third inclined surface 133 and the fourth inclined surface 134 is greater than the surface roughness of the first inclined surface 131 and the second inclined surface 132. Figure 18 In the figure, the third inclined surface 133 and the fourth inclined surface 134, which are located further back than the cross-section shown in this figure, are represented by multiple point regions.
[0082] Figure 19 The state of the substrate 81 after the main surface 11 and the protrusion 13 are formed on the substrate 81 by anisotropic etching and before the mask layer 89 is removed is also shown. However, the manufacturing method of the first mask layer 891 is different from that of the substrate 81. Figure 17 The manufacturing method of the first mask layer 891 shown is different. Like the second mask layer 892, the first mask layer 891 is formed by depressurized CVD. Therefore, the first mask layer 891 is more... Figure 17 The first mask layer 891 shown is more difficult to dissolve in the etching solution. Therefore, the portion 891A of the first mask layer 891 covering the third inclined surface 133 and the fourth inclined surface 134 of the protrusion 13 is not removed. Therefore, even if the properties of the first mask layer 891 are the same as those of the second mask layer 892, the third inclined surface 133 and the fourth inclined surface 134 will still be formed on the protrusion 13.
[0083] Next, as Figure 20 As shown, an insulating layer 21 is formed covering the main surface 11 and the protrusion 13 of the substrate 81. The insulating layer 21 is formed by multiple depositions of a silicon dioxide thin film formed using tetraethyl orthosilicate (TEOS) as a raw material gas via plasma CVD.
[0084] Next, as Figures 21-23As shown, a resistive layer 3 and a wiring layer 4 are formed. The resistive layer 3 includes a plurality of heating elements 31 arranged along the x-direction. The wiring layer 4 is electrically connected to the plurality of heating elements 31. Furthermore, the step of forming the wiring layer 4 includes the step 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 13 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 individual wirings 42 are positioned relative to... Figure 13 The multiple heating elements 31 shown are located on the other side in the y direction.
[0085] First, such as Figure 21 As shown, a resistive film 82 is formed on the main surface 11 and the protrusion 13 of the substrate 81. The resistive film 82 is formed to cover the entire surface of the insulating layer 21. The resistive film 82 is formed by depositing a tantalum nitride thin film on the insulating layer 21 using a sputtering method.
[0086] Next, as Figure 22 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 depositing 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 whereby a titanium thin film is deposited onto the resistive film 82 using a sputtering method, and then a copper thin film is deposited onto the titanium thin film multiple times using a sputtering method.
[0087] Next, as Figure 23 As shown, after photolithographically patterning 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). This forms a common wiring 41 and multiple individual wirings 42 grounded to the resistive film 82. Simultaneously, the region of the resistive film 82 formed on the top surface 130 of the protrusion 13 of the substrate 81 is exposed from the wiring layer 4. Then, after photolithographically patterning the resistive film 82 and the wiring layer 4, a portion of the resistive film 82 is removed. This removal is performed using reactive ion etching. This forms a resistive layer 3 on the main surface 11 and the protrusion 13 of the substrate 81. Multiple heat-generating portions 31 appear on the top surface 130 of the substrate 81.
[0088] Next, as Figure 24 As shown, a protective layer 5 is formed covering a portion of the main surface 11 of the substrate 81, multiple heating elements 31 of the resistive layer 3, and the wiring layer 4. The protective layer 5 is formed by laminating a silicon nitride thin film using plasma CVD.
[0089] Next, as Figure 25As shown, a wiring opening 51 extending along the z-direction is formed in the protective layer 5. The wiring opening 51 is formed by removing a portion of the protective layer 5 after photolithographic patterning. This removal is performed by reactive ion etching. This allows a portion of a plurality of individual wirings 42 to be removed. Figure 5 The base 421 of each of the plurality of individual wirings 42 and a portion of each of the extensions 422 of the plurality of individual wirings 42 are exposed from the wiring opening 51. The portion of each of the plurality of individual wirings 42 exposed from the wiring opening 51 is, for example, a base 421 for individually joining the plurality of first conductors 74 by wire bonding. Alternatively, a metal layer such as gold may be deposited on each portion (including the base 421) of the plurality of individual wirings 42 exposed from the wiring opening 51 by plating.
[0090] Next, the substrate 81 is cut along the x and y directions in the thickness direction. The resulting single piece becomes the main part of the thermal printhead A10 containing the substrate 1. As an example of a cutting device for the substrate 81, a cutting machine can be cited. The cutting line of the substrate 81 is set at a position away from the protrusion 13 of the substrate 81. This prevents the blade of the cutting device from contacting the protrusion 13.
[0091] Next, multiple drive elements 73 and connectors 77 are mounted on the wiring substrate 71. Then, the back surface 12 of the substrate 1 and the wiring substrate 71 are bonded to the heat dissipation component 72. Next, multiple first wires 74 and multiple second wires 75 are bonded to the wiring substrate 71. Finally, a sealing resin 76 is formed on the substrate 1 and the wiring substrate 71, covering the drive elements 73, the multiple first wires 74, and the multiple second wires 75. Through these steps, a thermal printhead A10 can be obtained.
[0092] Next, the function and effect of the thermal printhead A10 will be explained.
[0093] The thermal printhead A10 includes a substrate 1 having a main surface 11 and a protrusion 13, and comprising a semiconductor material. The protrusion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. A third inclined surface 133 and a fourth inclined surface 134 are formed at at least one of the two ends of the protrusion 13 in the x-direction. The third inclined surface 133 is inclined relative to the main surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined relative to the main surface 11 and the second inclined surface 132. Thus, the end face of the protrusion 13, located at at least one of the two ends of the protrusion 13 in the x-direction and connected to the main surface 11, the first inclined surface 131, and the second inclined surface 132, includes the third inclined surface 133 and the fourth inclined surface 134. This end face does not stand upright from the main surface 11 along the y- and z-directions, but is inclined relative to the main surface 11, the first inclined surface 131, and the second inclined surface 132. Therefore, according to the thermal printhead A10, it is possible to prevent the end of the protrusion 13 in the x-direction from becoming sharp.
[0094] The manufacturing process of the thermal printhead A10 includes the following steps: before forming the main surface 11 and the protrusion 13 on the substrate 81 by anisotropic etching, a mask layer 89 is formed on the first surface 81A and the second surface 81B of the substrate 81. The mask layer 89 includes a first mask layer 891 formed on the first surface 81A and a second mask layer 892 formed on the second surface 81B. The first mask layer 891 has a covered portion 891A, two first openings 891B, and a second opening 891C. The first surface 81A is exposed through the two first openings 891B and the second opening 891C. As a result, the protrusion 13, in addition to having a top surface 130, a first inclined surface 131, and a second inclined surface 132, can be formed, as well as a third inclined surface 133 and a fourth inclined surface 134.
[0095] The first mask layer 891 dissolves more readily in the etchant used for anisotropic etching than the second mask layer 892. Therefore, as... Figure 16 As shown, anisotropic etching is used to remove a portion of the covering portion 891A of the first mask layer 891 located on the third inclined surface 133 and the fourth inclined surface 134 of the protrusion 13. As a result, the mask layer 89 can be removed more efficiently after the main surface 11 and the protrusion 13 are formed on the substrate 81.
[0096] The third inclined surface 133 and the fourth inclined surface 134 of the protrusion 13 approach each other from the main surface 11 toward the top surface 130 of the protrusion 13. Furthermore, the third inclined surface 133 and the fourth inclined surface 134 are connected to the top surface 130 and are inclined relative to the top surface 130. As a result, the intersection angle of the third inclined surface 133 and the fourth inclined surface 134 with respect to the top surface 130 is obtuse. As a result, the third edge 130C and the fourth edge 130D forming the boundary between the third inclined surface 133 and the fourth inclined surface 134 and the top surface 130 can be prevented from becoming sharp.
[0097] In the top surface 130 of the protrusion 13, the third edge 130C is inclined relative to the first edge 130A in the x-direction. The fourth edge 130D is inclined relative to the second edge 130B in the x-direction. Furthermore, the third edge 130C and the fourth edge 130D move closer to each other as they move away from the first edge 130A and the second edge 130B in the x-direction. As a result, the area of the end of the top surface 130 in the x-direction gradually decreases as it moves away from the plurality of heating portions 31 of the resistive layer 3 in the x-direction. Therefore, the contact area of the end of the recording medium in the x-direction relative to the thermal printhead A10 becomes smaller. This makes it possible to suppress damage to the recording medium caused by contact with the thermal printhead A10.
[0098] The semiconductor material contained in substrate 1 comprises a single-crystal material composed of silicon. As a result, the thermal conductivity of substrate 1 is relatively high (approximately 170 W / (m·K)) and the cost of substrate 1 can be reduced.
[0099] The substrate 1 has a protrusion 13 protruding from the main surface 11 in the z-direction. Multiple heat-generating portions 31 of the resistive layer 3 are formed on the protrusion 13. Thus, in Figure 4 When printing on the recording medium shown, the contact area between the recording medium and the thermal printhead A10 can be minimized, and heat from multiple heating elements 31 can be transferred to the recording medium. This improves the printing quality on the recording medium.
[0100] The thermal printhead A10 also has a protective layer 5 covering both the multiple heating elements 31 of the resistive layer 3 and the wiring layer 4. Thus, the multiple heating elements 31 and the wiring layer 4 are protected by the protective layer 5, and the contact between the recording medium and the thermal printhead A10 becomes smoother when the thermal printhead A10 is used.
[0101] The thermal printhead A10 also includes a heat dissipation component 72. The back side 12 of the substrate 1 is bonded to the heat dissipation component 72. Thus, when using the thermal printhead A10, a portion of the heat generated from the multiple heat-generating parts 31 can be quickly released to the outside via the substrate 1 and the heat dissipation component 72.
[0102] [Second Implementation]
[0103] based on Figure 26 and Figure 27 The thermal printhead A20 of the second embodiment of this disclosure will be described. In these figures, elements that are the same as or similar to the thermal printhead A10 are labeled with the same symbols, and repeated descriptions are omitted. Here, Figure 26 The cross-sectional position represents the main part of the thermal printhead A10. Figure 5 The cross-sectional positions are the same.
[0104] The difference between thermal printhead A20 and thermal printhead A10 is that it also has a glaze layer 22.
[0105] like Figure 26 and Figure 27 As shown, the glaze layer 22 is located between the top surface 130 of the protrusion 13 and the insulating layer 21. The glaze layer 22 may contain, for example, amorphous glass. Therefore, the glaze layer 22 is made of a glass-containing material. The coefficient of linear expansion of the glaze layer 22 is similar to that of the substrate 1. Figure 27 As shown, the glaze layer 22 bulges out in the z-direction toward the side facing the top surface 130. 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.
[0106] Next, based on Figure 28 An example of the manufacturing method for the thermal printhead A20 will be described here. Figure 25 The cross-sectional position represents the main part of the thermal printhead A10. Figure 5 The cross-sectional positions are the same.
[0107] In the manufacturing steps of the main part of the thermal printhead A10 Figures 15-19 After the steps shown, as Figure 28 As shown, a glaze layer 22 is formed in contact with the top surface 130 of the protrusion 13. Figures 15-19 The steps shown involve removing the mask layer 89 after forming the main surface 11 and the protrusion 13 on the substrate 81. The glaze layer 22 is formed by supplying a glaze material, which is a fluid, to the top surface 130 and then firing the glaze material. This glaze material is, for example, sprayed from a dispenser. The glaze material contains glass such as amorphous glass. The glaze material can also be applied multiple times. Another example of the method of supplying the glaze material is to use a screen to print the glaze material onto the top surface 130. After forming the glaze layer 22, the process involves manufacturing steps related to the main part of the thermal printhead A10. Figures 20-25 The same steps shown can be used to obtain the thermal printhead A20.
[0108] Next, the function and effect of the thermal printhead A20 will be explained.
[0109] The thermal printhead A20 includes a substrate 1 having a main surface 11 and a protrusion 13, and comprising a semiconductor material. The protrusion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. At least one of the two ends of the protrusion 13 in the x-direction is formed with a third inclined surface 133 and a fourth inclined surface 134. The third inclined surface 133 is inclined relative to the main surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined relative to the main surface 11 and the second inclined surface 132. Therefore, the thermal printhead A20 can also suppress the end of the protrusion 13 in the x-direction from becoming sharp. Furthermore, the thermal printhead A20, by having a configuration common to the thermal printhead A10, performs the same function as the thermal printhead A10.
[0110] The thermal printhead A20 also includes a glaze layer 22 located between the top surface 130 of the protrusion 13 and the insulating layer 21. The glaze layer 22 bulges out in the z-direction toward the side facing the top surface 130. By adopting this configuration, the size of the protrusion 13 can be suppressed, and the contact area of the recording medium with respect to the thermal printhead A20 can be reduced. Furthermore, the glaze layer 22 functions to store heat generated from the multiple heating elements 31. Therefore, according to the thermal printhead A20, printing energy efficiency can be improved, and the printing quality on the recording medium completed by the multiple heating elements 31 can be improved.
[0111] [Third Implementation]
[0112] based on Figure 29 and Figure 30 The thermal printhead A30 of the third embodiment of this disclosure will be described. In these figures, elements that are the same as or similar to the thermal printhead A10 are labeled with the same symbols, and repeated descriptions are omitted. Here, Figure 29 The cross-sectional position represents the main part of the thermal printhead A10. Figure 5 The cross-sectional positions are the same.
[0113] In the thermal printhead A30, the configuration of the protrusion 13 of the substrate 1 and the configuration of the plurality of heating elements 31 of the resistive layer 3 are different from the corresponding configuration of the thermal printhead A10.
[0114] like Figure 29 and Figure 30As shown, the protrusion 13 has a fifth inclined surface 135 and a sixth inclined surface 136. The fifth inclined surface 135 and the sixth inclined surface 136 are connected to the top surface 130 of the protrusion 13 and are inclined relative to the main surface 11 and the top surface 130 of the substrate 1. The fifth inclined surface 135 is located on the side of the first inclined surface 131 of the protrusion 13 in the y-direction. The sixth inclined surface 136 is located on the side of the second inclined surface 132 of the protrusion 13 in the y-direction. The fifth inclined surface 135 and the sixth inclined surface 136 move closer to each other from the main surface 11 toward the top surface 130.
[0115] like Figure 30 As shown, the tilt angles γ of the fifth tilting surface 135 and the sixth tilting surface 136 relative to the main surface 11 are equal. The tilt angle γ of the fifth tilting surface 135 is smaller than the tilt angle α of the first tilting surface 131 relative to the main surface 11. The tilt angle γ of the sixth tilting surface 136 is smaller than the tilt angle α of the second tilting surface 132 relative to the main surface 11. The fifth tilting surface 135 and the sixth tilting surface 136 can be related to the manufacturing of the thermal printhead A10. Figure 15 The steps shown are the same as Figure 20 The steps shown are performed between the following steps. This step involves wet etching of the boundary between the top surface 130 and the first inclined surface 131, and the boundary between the top surface 130 and the second inclined surface 132, using an aqueous solution of tetramethylammonium hydroxide (TMAH).
[0116] like Figure 30 As shown, a plurality of heating elements 31 of the resistive layer 3 are formed on the top surface 130, the sixth inclined surface 136 and the second inclined surface 132 of the protrusion 13. Alternatively, the plurality of heating elements 31 may also be formed on the top surface 130, the fifth inclined surface 135 and the first inclined surface 131 of the protrusion 13.
[0117] Next, the function and effect of the thermal printhead A30 will be explained.
[0118] The thermal printhead A30 includes a substrate 1 having a main surface 11 and a protrusion 13, and comprising a semiconductor material. The protrusion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. A third inclined surface 133 and a fourth inclined surface 134 are formed at at least one of the two ends in the x-direction of the protrusion 13. The third inclined surface 133 is inclined relative to the main surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined relative to the main surface 11 and the second inclined surface 132. Therefore, the thermal printhead A30 can also suppress the end of the protrusion 13 in the x-direction from becoming sharp. Furthermore, the thermal printhead A30, by having a configuration common to the thermal printhead A10, performs the same function as the thermal printhead A10.
[0119] In the thermal printhead A30, the protrusion 13 has a fifth inclined surface 135 and a sixth inclined surface 136. The fifth inclined surface 135 and the sixth inclined surface 136 are connected to the top surface 130 of the protrusion 13 and are inclined relative to the main surface 11 and the top surface 130 of the substrate 1. The inclination angle γ of the fifth inclined surface 135 is smaller than the inclination angle α of the first inclined surface 131 relative to the main surface 11. The inclination angle γ of the sixth inclined surface 136 is smaller than the inclination angle α of the second inclined surface 132 relative to the main surface 11. By adopting this configuration, the shape of a portion of the wiring layer 4 formed along the protrusion 13 becomes smoother. At the same time, the occurrence of defects or breaks in the wiring pattern in the wiring layer 4 formed along the protrusion 13 is suppressed.
[0120] This disclosure is not limited to the described embodiments. The specific configuration of each part of this disclosure can be freely modified in various ways.
[0121] The following notes describe the technical composition of the thermal printhead and its manufacturing method provided in this disclosure.
[0122] [Note 1]
[0123] A thermal printhead comprises: a substrate having a main surface facing the thickness direction and a protrusion protruding from the main surface and extending along the main scanning direction, and comprising a semiconductor material;
[0124] A resistive layer comprising a plurality of heating elements arranged along the main scanning direction and located above the protrusion; and
[0125] The wiring layer is electrically connected to the plurality of heating elements and grounded to the resistive layer;
[0126] The protrusion has: a top surface facing the thickness direction and located away from the main surface; and a first inclined surface and a second inclined surface connected to the main surface and located separately from each other in the sub-scanning direction, and inclined relative to the main surface;
[0127] At least one of the two ends of the protrusion in the main scanning direction is provided with a third inclined surface connected to the main surface and the first inclined surface, and a fourth inclined surface connected to the main surface and the second inclined surface.
[0128] The third inclined surface is inclined relative to the main surface and the first inclined surface, and
[0129] The fourth inclined surface is inclined relative to the main surface and the second inclined surface.
[0130] [Note 2]
[0131] According to the thermal printhead described in Note 1, the area of the third inclined surface is smaller than the area of the first inclined surface, and
[0132] The area of the fourth inclined surface is smaller than the area of the second inclined surface.
[0133] [Note 3]
[0134] According to the thermal printhead described in Note 2, wherein the first inclined surface and the second inclined surface approach each other from the main surface toward the top surface, and
[0135] The third inclined surface and the fourth inclined surface move closer to each other as they move from the main surface toward the top surface.
[0136] [Note 4]
[0137] According to the thermal printhead described in Note 3, the first inclined surface and the second inclined surface are connected to the top surface and are inclined relative to the top surface, and
[0138] The third and fourth inclined surfaces are connected to the top surface and are inclined relative to the top surface.
[0139] [Note 5]
[0140] According to the thermal printhead described in Note 4, the periphery of the top surface includes a first edge forming a boundary with the first inclined surface, a second edge forming a boundary with the second inclined surface, a third edge forming a boundary with the third inclined surface, and a fourth edge forming a boundary with the fourth inclined surface.
[0141] The third edge is inclined relative to the first edge in the main scanning direction, and
[0142] The fourth edge is inclined relative to the second edge in the main scanning direction.
[0143] [Note 6]
[0144] According to the thermal printhead described in Note 5, the third edge and the fourth edge move closer to each other as they move away from the first edge and the second edge in the main scanning direction.
[0145] [Note 7]
[0146] According to the thermal printhead described in Note 3, the protrusion has a fifth inclined surface and a sixth inclined surface that are connected to the top surface and inclined relative to the main surface and the top surface.
[0147] The fifth inclined surface is located on the same side as the first inclined surface in the sub-scanning direction.
[0148] The sixth inclined surface is located on the same side as the second inclined surface in the sub-scanning direction.
[0149] The fifth and sixth inclined surfaces move closer to each other as they move from the main surface toward the top surface.
[0150] The tilt angle of the fifth inclined surface relative to the main surface is smaller than the tilt angle of the first inclined surface relative to the main surface, and
[0151] The tilt angle of the sixth inclined surface relative to the main surface is smaller than the tilt angle of the second inclined surface relative to the main surface.
[0152] [Note 8]
[0153] According to any one of notes 3 to 7, the thermal printhead wherein the third inclined surface and the fourth inclined surface are connected to each other in the sub-scanning direction.
[0154] [Note 9]
[0155] According to the thermal printhead described in Note 8, the ridge forming the boundary between the third inclined surface and the fourth inclined surface is inclined relative to the main surface.
[0156] [Note 10]
[0157] According to the thermal printhead described in Note 9, when viewed along the thickness direction, the ridge is located further outward than the top surface in the main scanning direction.
[0158] [Note 11]
[0159] According to any one of Notes 3 to 10, the surface roughness of the third inclined surface is greater than the surface roughness of the first inclined surface, and
[0160] The surface roughness of the fourth inclined surface is greater than that of the second inclined surface.
[0161] [Note 12]
[0162] The thermal printhead according to any one of notes 1 to 11 further comprises an insulating layer covering the main surface and the protrusion, and
[0163] The insulating layer is located between the substrate and the resistive layer.
[0164] [Note 13]
[0165] According to any one of Notes 1 to 12, the thermal printhead wherein the wiring layer comprises common wiring and a plurality of individual wirings.
[0166] The common wiring is connected to the plurality of heating elements, and
[0167] The plurality of individual wirings are individually connected to the plurality of heating elements.
[0168] [Note 14]
[0169] The thermal printhead according to any one of notes 1 to 13 further comprises a protective layer covering the plurality of heating elements and the wiring layer.
[0170] [Note 15]
[0171] According to any one of Notes 1 to 14, the thermal printhead wherein the substrate has a back side facing the side opposite to the main surface in the thickness direction.
[0172] The thermal printhead also has a heat dissipation component, and
[0173] The back side is attached to the heat dissipation component.
[0174] [Note 16]
[0175] A method for manufacturing a thermal printhead includes the following steps: forming a mask layer on the first surface and the second surface in a substrate having a first surface and a second surface and containing a semiconductor material, wherein the first surface and the second surface face opposite sides to each other in the thickness direction;
[0176] A main surface and a protrusion are formed on the substrate by anisotropic etching. The main surface faces the same direction as the first surface in the thickness direction and is located between the first surface and the second surface. The protrusion protrudes from the main surface.
[0177] Remove the mask layer;
[0178] A resistive layer is formed, the resistive layer comprising a plurality of heating elements arranged along the main scanning direction on the protrusion; and
[0179] A wiring layer is formed that is grounded to the resistive layer and is connected to the plurality of heating elements;
[0180] The mask layer includes a first mask layer formed on the first surface and a second mask layer formed on the second surface.
[0181] The first mask layer has: a covered portion extending along the main scanning direction and covering the first surface; two first openings located at a position spaced apart from the covered portion in the sub-scanning direction and extending along the main scanning direction; and a second opening located next to the end of the covered portion in the main scanning direction and connected to the two first openings; and
[0182] The first surface is exposed from the two first openings and the second opening.
[0183] [Note 17]
[0184] According to the method for manufacturing a thermal printhead as described in Note 16, the first mask layer is more readily soluble in the etchant used for the anisotropic etching than the second mask layer.
[0185] [Note 18]
[0186] According to the method for manufacturing a thermal printhead described in Note 17, wherein the first mask layer is formed by plasma CVD, and
[0187] The second mask layer is formed by depressurized CVD.
[0188] [Explanation of Symbols]
[0189] A10, A20 thermal printheads
[0190] B10 Thermal Printer
[0191] 1 Substrate
[0192] 11 Main side
[0193] 12 Back
[0194] 13 convex part
[0195] 130 Top surface
[0196] 130A First Edge
[0197] 130B Second Edge
[0198] 130C Third Edge
[0199] 130D 4th Edge
[0200] 131 First Inclined Surface
[0201] 132 Second Inclined Surface
[0202] 133 Third Inclined Surface
[0203] 134 Fourth Inclined Surface
[0204] 135 Fifth Inclined Surface
[0205] 136 Sixth Inclined Surface
[0206] 139 Edges
[0207] 21 Insulation layer
[0208] 22 glaze layers
[0209] 3 Resistor layer
[0210] 31 Heating section
[0211] 4. Wiring layer
[0212] 41 Common wiring
[0213] 411 Base
[0214] 412 Extended Section
[0215] 42 Individual wiring
[0216] 421 Base
[0217] 422 Extension Section
[0218] 5 protective layers
[0219] 51 Wiring Opening
[0220] 71 Wiring Substrate
[0221] 72 Heat dissipation components
[0222] 73 Driving Components
[0223] 74 First conductor
[0224] 75. Second conductor
[0225] 76 Sealing Resin
[0226] 77 Connector
[0227] 79. Paper Press Roller
[0228] 81 Substrate
[0229] 81A Side 1
[0230] 81B Page 2
[0231] 82 Resistor Film
[0232] 83 Conductive layer
[0233] 89 Mask layer
[0234] 891 First Mask Layer
[0235] 891A Covered part
[0236] 891B First Opening
[0237] 891C Second Opening
[0238] 892 Second mask layer
[0239] α,β1,β2,γ inclination angle.
Claims
1. A thermal printhead comprising: a substrate having a main surface facing a thickness direction and a protrusion protruding from the main surface and extending along a main scanning direction, and comprising a semiconductor material; A resistive layer comprising a plurality of heating elements arranged along the main scanning direction and located on the protrusion; and The wiring layer is electrically connected to the plurality of heating elements and grounded to the resistive layer; The protrusion has: a top surface facing the thickness direction and located away from the main surface; and a first inclined surface and a second inclined surface connected to the main surface and located separately from each other in the sub-scanning direction, and inclined relative to the main surface; At least one of the two ends of the protrusion in the main scanning direction is provided with a third inclined surface connected to the main surface and the first inclined surface, and a fourth inclined surface connected to the main surface and the second inclined surface. The third inclined surface is inclined relative to the main surface and the first inclined surface, and The fourth inclined surface is inclined relative to the main surface and the second inclined surface.
2. The thermal printhead according to claim 1, wherein the area of the third inclined surface is smaller than the area of the first inclined surface, and The area of the fourth inclined surface is smaller than the area of the second inclined surface.
3. The thermal printhead according to claim 2, wherein the first inclined surface and the second inclined surface approach each other from the main surface toward the top surface, and The third inclined surface and the fourth inclined surface move closer to each other as they move from the main surface toward the top surface.
4. The thermal printhead according to claim 3, wherein the first inclined surface and the second inclined surface are connected to the top surface and are inclined relative to the top surface, and The third and fourth inclined surfaces are connected to the top surface and are inclined relative to the top surface.
5. The thermal printhead according to claim 4, wherein the periphery of the top surface includes a first edge forming a boundary with the first inclined surface, a second edge forming a boundary with the second inclined surface, a third edge forming a boundary with the third inclined surface, and a fourth edge forming a boundary with the fourth inclined surface. The third edge is inclined relative to the first edge in the main scanning direction, and The fourth edge is inclined relative to the second edge in the main scanning direction.
6. The thermal printhead of claim 5, wherein the third edge and the fourth edge move closer to each other as they move away from the first edge and the second edge in the main scanning direction.
7. The thermal printhead according to claim 3, wherein the protrusion has a fifth inclined surface and a sixth inclined surface connected to the top surface and inclined relative to the main surface and the top surface. The fifth inclined surface is located on the same side as the first inclined surface in the sub-scanning direction. The sixth inclined surface is located on the same side as the second inclined surface in the sub-scanning direction. The fifth and sixth inclined surfaces move closer to each other as they move from the main surface toward the top surface. The tilt angle of the fifth inclined surface relative to the main surface is smaller than the tilt angle of the first inclined surface relative to the main surface, and The tilt angle of the sixth inclined surface relative to the main surface is smaller than the tilt angle of the second inclined surface relative to the main surface.
8. The thermal printhead according to any one of claims 3 to 7, wherein the third inclined surface and the fourth inclined surface are connected to each other in the sub-scanning direction.
9. The thermal printhead of claim 8, wherein the ridge forming the boundary between the third inclined surface and the fourth inclined surface is inclined relative to the main surface.
10. The thermal printhead of claim 9, wherein, when viewed along the thickness direction, the ridge is located further outward than the top surface in the main scanning direction.
11. The thermal printhead according to any one of claims 1 to 7, wherein the surface roughness of the third inclined surface is greater than the surface roughness of the first inclined surface, and The surface roughness of the fourth inclined surface is greater than that of the second inclined surface.
12. The thermal printhead according to any one of claims 1 to 7, further comprising an insulating layer covering the main surface and the protrusion, and The insulating layer is located between the substrate and the resistive layer.
13. The thermal printhead according to any one of claims 1 to 7, wherein the wiring layer comprises common wiring and a plurality of individual wirings. The common wiring is connected to the plurality of heating elements, and The plurality of individual wirings are individually connected to the plurality of heating elements.
14. The thermal printhead according to any one of claims 1 to 7, further comprising a protective layer covering the plurality of heating elements and the wiring layer.
15. The thermal printhead according to any one of claims 1 to 7, wherein the substrate has a back side facing a side opposite to the main surface in the thickness direction. The thermal printhead also has a heat dissipation component, and The back side is attached to the heat dissipation component.
16. A method for manufacturing a thermal printhead, comprising the following steps: forming a mask layer on the first surface and the second surface in a substrate having a first surface and a second surface and comprising a semiconductor material, wherein the first surface and the second surface are oriented toward opposite sides in the thickness direction; A main surface and a protrusion are formed on the substrate by anisotropic etching. The main surface faces the same direction as the first surface in the thickness direction and is located between the first surface and the second surface. The protrusion protrudes from the main surface. Remove the mask layer; A resistive layer is formed, the resistive layer comprising a plurality of heating elements arranged along the main scanning direction on the protrusion; and A wiring layer is formed that is grounded to the resistive layer and is connected to the plurality of heating elements; The mask layer includes a first mask layer formed on the first surface and a second mask layer formed on the second surface. The first mask layer has: a covered portion extending along the main scanning direction and covering the first surface; Two first openings are located at a position in the sub-scanning direction that is spaced apart from the covered portion, and extend along the main scanning direction; The second opening is located next to the end of the covered portion in the main scanning direction and is connected to the two first openings; The first surface is exposed from the two first openings and the second opening; The protrusion has a first inclined surface and a second inclined surface, which are connected to the main surface and located at positions that are separated from each other in the sub-scanning direction, and are inclined relative to the main surface; At least one of the two ends of the protrusion in the main scanning direction is provided with a third inclined surface connected to the main surface and the first inclined surface, and a fourth inclined surface connected to the main surface and the second inclined surface. The third inclined surface is inclined relative to the main surface and the first inclined surface, and The fourth inclined surface is inclined relative to the main surface and the second inclined surface.
17. The method of manufacturing a thermal printhead according to claim 16, wherein the first mask layer is more readily soluble in the etchant used for the anisotropic etching than the second mask layer.
18. The method for manufacturing a thermal printhead according to claim 17, wherein the first mask layer is formed by plasma CVD, and The second mask layer is formed by depressurized CVD.