Thermal printhead and method for manufacturing the same

Abstract

To provide a thermal print head and the manufacturing method, which can suppress sharpening of an end in a main scanning direction of a protrusion of a substrate.SOLUTION: A thermal print head A10 includes: a substrate 1 which has a principal surface 11 and a protrusion 13 and contains a semiconductor material; a resistor layer 3 which includes a plurality of heating sections 31 positioned on the protrusion 13; and a wiring layer 4 which is conducted with the plurality of heating sections 31 and is formed to be in contact with the resistor layer 3. The protrusion 13 has a top face 130, a first inclined surface 131, and a second inclined surface 132. A third inclined surface 133 connected to the principal surface 11 and the first inclined surface 131 and a fourth inclined surface 134 connected to the principal surface 11 and the second inclined surface 132 are formed at least at either end of both ends in a main scanning direction of the protrusion 13. The third inclined surface 133 is inclined to the principal surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined to the principal surface 11 and the second inclined surface 132.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present 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 a material containing silicon. The substrate of the thermal printhead has a main surface and a convex portion extending in the main scanning direction and protruding from the main surface. As shown in FIG. 6 of Patent Document 1, the heat generating portions are arranged in the main scanning direction on the convex portion. With this configuration, the recording medium can be brought into contact with the convex portion on which the heat generating portions are arranged accurately, and therefore improvement in print quality can be expected. Furthermore, the substrate of the thermal printhead has an advantage that it has a relatively high thermal conductivity and is less expensive than a substrate made of a material containing aluminum nitride. However, in the thermal printhead, the end face of the convex portion located at the end of the convex portion in the main scanning direction is steeply raised from the main surface. For this reason, the end of the convex portion in the main scanning direction is likely to be sharp. If the end becomes sharp, there is a risk of damage to the recording medium, and therefore improvement is desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-166824 A Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above circumstances, an object of the present disclosure is to provide a thermal printhead that can prevent edges of convex portions of a substrate in the main scanning direction from becoming sharp, and a method for manufacturing the same. [Means for solving the problem]

[0005] A thermal printhead provided by a first aspect of the present disclosure comprises a substrate including a semiconductor material and a main surface facing a thickness direction and a convex portion protruding from the main surface and extending in a main scanning direction, a resistor layer including a plurality of heating portions arranged in the main scanning direction and positioned on the convex portion, and a wiring layer formed in contact with the resistor layer, the convex portion having a top surface facing the thickness direction and positioned away from the main surface, and a first inclined surface and a second inclined surface connected to the main surface and positioned away from each other in the sub-scanning direction and inclined with respect to the main surface, at least one of both ends of the convex portion in the main scanning direction is formed 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 with respect to the main surface and the first inclined surface, and the fourth inclined surface is inclined with respect to the main surface and the second inclined surface,

[0006] A method for manufacturing a thermal printhead provided by a second aspect of the present disclosure includes the steps of: forming a mask layer on a substrate having a first surface and a second surface facing opposite each other in a thickness direction and including a semiconductor material; forming, by anisotropic etching, a main surface facing the same direction as the first surface in the thickness direction and located between the first surface and the second surface, and a convex portion protruding from the main surface, on the substrate; removing the mask layer; and forming a resistor layer including a plurality of heating portions arranged in a main scanning direction on the convex portion. and forming a wiring layer in contact with the resistor layer, the wiring layer being conductive to the plurality of heat generating portions, the mask layer including 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 covering portion extending in the main scanning direction and covering the first surface, two first openings positioned on either side of the covering portion in the sub-scanning direction and extending in the main scanning direction, and a second opening positioned adjacent to an end of the covering portion in the main scanning direction and connected to the two first openings, the first surface being exposed from the two first openings and the second opening. Effect of the Invention

[0007] According to the thermal printhead and the method of manufacturing the same disclosed herein, the ends of the convex portions of the substrate in the main scanning direction can be prevented from becoming sharp.

[0008] Other features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view of a thermal printhead according to a first embodiment of the present disclosure, seen through a protective layer. [Diagram 2] FIG. 2 is a plan view of the main part of the thermal printhead shown in FIG. [Diagram 3] FIG. 3 is a partially enlarged view of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a cross-sectional view of a main part of the thermal printhead shown in FIG. [Figure 6] FIG. 6 is a partially enlarged view of FIG. [Figure 7] FIG. 7 is a partially enlarged view of FIG. 1, showing the insulating layer, the resistor layer and the wiring layer in a more transparent manner. [Figure 8] FIG. 8 is a right side view corresponding to FIG. [Figure 9] FIG. 9 is a front view corresponding to FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along the line XX in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] 12A to 12C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 13] 13A to 13C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 14] 14A to 14C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 15] 15A to 15C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 16] FIG. 16 is a partially enlarged plan view illustrating the manufacturing process of the main part of the thermal printhead shown in FIG. [Figure 17] FIG. 17 is a partially enlarged plan view illustrating the manufacturing process of the main part of the thermal printhead shown in FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. [Figure 19] FIG. 19 is a partially enlarged plan view illustrating the manufacturing process of the main part of the thermal printhead shown in FIG. [Figure 20] 20A to 20C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 21] 21A to 21C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 22] 22A to 22C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 23] 23A to 23C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 24] 24A to 24C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Diagram 25] 25A to 25C are cross-sectional views illustrating the manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 26] FIG. 26 is a cross-sectional view of a main part of a thermal printhead according to the second embodiment of the present disclosure. [Figure 27] FIG. 27 is a partially enlarged view of FIG. [Figure 28] FIG. 28 illustrates a manufacturing process for the main part of the thermal printhead shown in FIG. [Figure 29]FIG. 29 is a cross-sectional view of a main part of a thermal printhead according to a third embodiment of the present disclosure. [Diagram 30] FIG. 30 is a partially enlarged view of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0011] [First embodiment] A thermal printhead A10 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 11. The thermal printhead A10 constitutes a main part of a thermal printer B10 described later. The thermal printhead A10 is composed of a main part and an associated part. The main part of the thermal printhead A10 includes a substrate 1, an insulating layer 21, a resistor layer 3, a wiring layer 4, and a protective layer 5. The associated part of the thermal printhead A10 includes a wiring board 71, a heat dissipation member 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 FIG. 1, for ease of understanding, the protective layer 5 is shown through, and the first wires 74, the second wires 75, and the sealing resin 76 are omitted. In FIG. 2 and FIG. 3, for ease of understanding, the protective layer 5 is shown through.

[0012] For ease of explanation, the main scanning direction of the thermal printhead A10 is called the "x direction." The sub-scanning direction of the thermal printhead A10 is called the "y direction." The thickness direction of the substrate 1 is called the "z direction." The z direction is perpendicular to both the x and y directions. In the following explanation, "viewed along the z direction" refers to "viewed along the thickness direction."

[0013] In the thermal printhead A10, as shown in FIG. 4, the substrate 1, which constitutes the main part of the thermal printhead A10, is joined to a heat dissipation member 72. Furthermore, the wiring substrate 71 is located next to the substrate 1 in the y direction. The wiring substrate 71 is fixed to the heat dissipation member 72, just like the substrate 1. A plurality of heat generating portions 31 (described in detail later) which form part of the resistor layer 3 and are arranged in the x direction are formed on the substrate 1. The plurality of heat generating portions 31 are selectively heated by a plurality of drive elements 73 mounted on the wiring substrate 71. The plurality of drive elements 73 are driven in accordance with a print signal transmitted from the outside via a connector 77.

[0014] Further, the thermal printer B10 according to the present disclosure includes a thermal printhead A10 and a platen roller 79, as shown in FIG. 4. In the thermal printer B10, the platen roller 79 is a roller-shaped mechanism that feeds a recording medium such as thermal paper. The platen roller 79 presses the recording medium against a plurality of heat generating parts 31, and the plurality of heat generating parts 31 print on the recording medium. In the thermal printer B10, a mechanism that is not a roller-shaped mechanism can be used instead of the platen roller 79. The mechanism has a flat surface. Here, the flat surface includes a curved surface having a small curvature. In the thermal printer B10, the roller-shaped mechanism such as the platen roller 79 and the mechanism are collectively called a "platen". Here, for convenience of explanation, the side of the supply source of the recording medium in FIG. 4 (the right side in FIG. 4) is called the "upstream side". In FIG. 4, the side of the destination of the recording medium (the left side in FIG. 4) is called the "downstream side".

[0015] As shown in Fig. 1, the substrate 1 has a rectangular shape extending in the x direction when viewed along the z direction. Therefore, the x direction corresponds to the long side direction of the substrate 1. The y direction corresponds to the short side direction of the substrate 1. The substrate 1 includes a semiconductor material. The semiconductor material includes a single crystal material containing silicon (Si).

[0016] As shown in Fig. 5, the substrate 1 has a main surface 11 and a back surface 12 facing opposite each other in the z direction. The plane orientations of the main surface 11 and the back surface 12 based on the crystal structure of the substrate 1 are both (100) planes. As shown in Fig. 4, in the thermal printhead A10, the main surface 11 faces the platen roller 79, and the back surface 12 faces the wiring substrate 71.

[0017] As shown in Fig. 5, the substrate 1 has a protrusion 13. The protrusion 13 protrudes in the z direction from the main surface 11. As shown in Fig. 1 and Fig. 2, the protrusion 13 extends in the x direction.

[0018] As shown in FIG. 5 and FIG. 6, 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 in 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 away from each other 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 with respect to the main surface 11. The first inclined surface 131 and the second inclined surface 132 approach each other as they move from the main surface 11 toward the top surface 130. The inclination angles α of the first inclined surface 131 and the second inclined surface 132 with respect to the main surface 11 are equal to each other.

[0019] As shown in FIG. 7, a third inclined surface 133 and a fourth inclined surface 134 are formed on at least one of both ends in the x direction of the protrusion 13. In the thermal printhead A10, the third inclined surface 133 and the fourth inclined surface 134 are formed on each of the both 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 with respect 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 with respect 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.

[0020] 11, the third inclined surface 133 and the fourth inclined surface 134 approach each other from the main surface 11 toward the top surface 130. The inclination angle β1 of the third inclined surface 133 with respect to the main surface 11 and the inclination angle β2 of the fourth inclined surface 134 with respect to the main surface 11 are each greater than the above-mentioned inclination angle α.

[0021] 10 and 11, the surface roughness of the third inclined surface 133 is greater than the surface roughness of the first inclined surface 131. The surface roughness of the fourth inclined surface 134 is greater than the surface roughness of the second inclined surface 132.

[0022] As shown in FIG. 7, 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 a boundary between the top surface 130 and a first inclined surface 131. The second edge 130B forms a boundary between the top surface 130 and a 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 a boundary with the third inclined surface 133. The third inclined surface 133 is inclined with respect to the first edge 130A in the x-direction. The fourth edge 130D is connected to the second edge 130B and forms a boundary with the fourth inclined surface 134. The fourth inclined surface 134 is inclined with respect to the second edge 130B in the x-direction.

[0023] 7, the third edge 130C and the fourth edge 130D of the top surface 130 approach each other as they move away from the first edge 130A and the second edge 130B of the top surface 130 in the x direction. The end of the third edge 130C located opposite the first edge 130A and the end of the fourth edge 130D located opposite the second edge 130B are connected to each other.

[0024] 7 and 9, the third inclined surface 133 and the fourth inclined surface 134 are connected to each other in the y direction. As shown in Fig. 8, a ridge line 139 forming a boundary between the third inclined surface 133 and the fourth inclined surface 134 is inclined with respect to the main surface 11. As shown in Fig. 7, when viewed along the z direction, the ridge line 139 is located outward in the x direction from the top surface 130.

[0025] As shown in Figures 5 and 6, the insulating layer 21 covers the main surface 11 and the protrusions 13 of the substrate 1. The insulating layer 21 electrically insulates the substrate 1 from the resistor layer 3 and the wiring layer 4. The insulating layer 21 is made of silicon dioxide (SiO2) using tetraethyl orthosilicate (TEOS) as a raw material, for example. The thickness of the insulating layer 21 is, for example, 1 µm or more and 15 µm or less.

[0026] The resistor layer 3 is formed on the main surface 11 and the protrusions 13 of the substrate 1, as shown in Fig. 5 and Fig. 6. The resistor 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 resistor layer 3. The resistor layer 3 is made of, for example, tantalum nitride (TaN). An example of the thickness of the resistor layer 3 is not less than 0.02 µm and not more than 0.1 µm.

[0027] As shown in FIG. 2, FIG. 3, and FIG. 6, the resistor layer 3 includes a plurality of heat generating portions 31. In the resistor layer 3, the plurality of heat generating portions 31 are exposed from the wiring layer 4. When the plurality of heat generating portions 31 are selectively energized from the wiring layer 4, the plurality of heat generating portions 31 locally heat the recording medium. The plurality of heat generating portions 31 are arranged in the x direction. Among the plurality of heat generating portions 31, two adjacent heat generating portions 31 in the x direction are located apart from each other. The plurality of heat generating portions 31 are formed in contact with the insulating layer 21. In the thermal printhead A10, the plurality of heat generating portions 31 are formed on the top surface 130 of the convex portion 13 of the substrate 1. The plurality of heat generating portions 31 are located at the center of the top surface 130 in the y direction. As shown in FIG. 4, in the thermal printer B10, the plurality of heat generating portions 31 face the platen roller 79.

[0028] The wiring layer 4 is formed in contact with the resistor layer 3 as shown in FIG. 5 and FIG. 6. The wiring layer 4 forms a conductive path for passing electricity to the multiple heating parts 31 of the resistor layer 3. The electrical resistivity of the wiring layer 4 is smaller than that of the resistor layer 3. The wiring layer 4 is a metal layer made of, for example, 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 may be configured of two metal layers, a titanium (Ti) layer laminated on the resistor layer 3 and a copper layer laminated 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. As shown in FIG. 1, the wiring layer 4 is located away from the periphery of the main surface 11 of the substrate 1.

[0029] 2, the wiring layer 4 includes a common wiring 41 and a plurality of individual wirings 42. The common wiring 41 is located downstream of the plurality of heat generating portions 31 of the resistor layer 3. The plurality of individual wirings 42 are located upstream of the plurality of heat generating portions 31. As shown in FIG. 3, when viewed along the z direction, a plurality of regions of the resistor layer 3 sandwiched between the common wiring 41 and the plurality of individual wirings 42 are the plurality of heat generating portions 31.

[0030] As shown in FIG. 2 and FIG. 3, the common wiring 41 has a base 411 and a plurality of extensions 412. In the y direction, the base 411 is located farthest from the plurality of heat generating parts 31 of the resistor layer 3. The base 411 is strip-shaped extending in the x direction when viewed along the z direction. The plurality of extensions 412 are strip-shaped extending from an end of the base 411 facing the protrusion 13 of the substrate 1 in the y direction toward the plurality of heat generating parts 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 second inclined surface 132 of the protrusion 13. In the common wiring 41, a current flows from the base 411 to the plurality of heat generating parts 31 via the plurality of extensions 412.

[0031] 2 and 3, each of the multiple individual wires 42 has a base portion 421 and an extension portion 422. In the y direction, the base portion 421 is located farthest from the multiple heat generating portions 31 of the resistor layer 3. The base portions 421 of the multiple individual wires 42 are arranged at equal intervals in a staggered arrangement in the x direction.

[0032] As shown in FIG. 2 and FIG. 3, the extension portion 422 is a strip extending from an end of the base portion 421 facing the protrusion 13 of the substrate 1 in the y direction toward the heat generating portions 31. The extension portions 422 of the individual wirings 42 are arranged along the x direction. The extension portion 422 of each of the individual wirings 42 is formed on the first inclined surface 131 of the protrusion 13. In each of the individual wirings 42, a current flows from one of the heat generating portions 31 to the base portion 421 via the extension portion 422. When viewed along the z direction, each of the heat generating portions 31 is sandwiched between one of the extension portions 422 of the individual wirings 42 and one of the extension portions 412 of the common wiring 41. The configurations of the wiring layer 4 and the heat generating portions 31 shown in FIG. 2 and FIG. 3 are examples. The configurations of the wiring layer 4 and the heat generating portions 31 in the present disclosure are not limited to the configurations shown in FIG. 2 and FIG. 3.

[0033] As shown in FIG. 5, the protective layer 5 covers a part of the main surface 11 of the substrate 1, the plurality of heat generating parts 31 of the resistor layer 3, and the wiring layer 4. The protective layer 5 has electrical insulation properties. The protective layer 5 contains silicon in its composition. The protective layer 5 is made of, for example, silicon dioxide, silicon nitride (Si3N4), or silicon carbide (SiC). Alternatively, the protective layer 5 may be a laminate made of a plurality of types of these materials. An example of the thickness of the protective layer 5 is 1.0 μm or more and 10 μm or less. In the thermal printer B10, the recording medium is pressed against the area of ​​the protective layer 5 that covers the plurality of heat generating parts 31 by the platen roller 79 shown in FIG. 4.

[0034] 5, the protective layer 5 has a wiring opening 51. The wiring opening 51 penetrates the protective layer 5 in the z-direction. From the wiring opening 51, the base portions 421 of the multiple individual wires 42 and parts of the extension portions 422 of the multiple individual wires 42 are exposed.

[0035] As shown in FIG. 4, the wiring board 71 is located next to the substrate 1 in the y direction. As shown in FIG. 1, as viewed along the z direction, the multiple individual wirings 42 are located between the multiple heat generating portions 31 of the resistor layer 3 and the wiring board 71 in the y direction. As viewed along the z direction, the area of ​​the wiring board 71 is larger than the area of ​​the substrate 1. Furthermore, as viewed along the z direction, the wiring board 71 has a rectangular shape with the x direction as the longitudinal direction. The wiring board 71 is, for example, a PCB substrate. A multiple driving element 73 and a connector 77 are mounted on the wiring board 71.

[0036] As shown in Fig. 4, the heat dissipation member 72 faces the rear surface 12 of the substrate 1. The rear surface 12 is joined to the heat dissipation member 72. The wiring board 71 is fixed to the heat dissipation member 72 by fastening members such as screws. When the thermal printhead A10 is in use, some of the heat generated from the multiple heat generating portions 31 of the resistor layer 3 is conducted to the heat dissipation member 72 via the substrate 1. The heat conducted to the heat dissipation member 72 is dissipated to the outside. The heat dissipation member 72 is made of, for example, aluminum (Al).

[0037] As shown in FIG. 1 and FIG. 4, the plurality of driving elements 73 are mounted on the wiring board 71 via an electrically insulating die bonding material (not shown). Each of the plurality of driving elements 73 is a semiconductor element in which various circuits are configured. Each of the plurality of driving elements 73 is joined to one end of each of the plurality of first wires 74 and one end of each of the plurality of second wires 75. The other end of each of the plurality of first wires 74 is individually joined to the bases 421 of the plurality of individual wirings 42. The other end of each of the plurality of second wires 75 is joined to wiring (not shown) provided on the wiring board 71 and conductive to the connector 77. As a result, a print signal, a control signal, and a voltage supplied to the plurality of heat generating parts 31 of the resistor layer 3 are input from the outside to the plurality of driving elements 73 via the connector 77. The plurality of driving elements 73 selectively apply a voltage to the plurality of individual wirings 42 based on these electric signals. As a result, the plurality of heat generating parts 31 selectively generate heat.

[0038] As shown in Fig. 4, the sealing resin 76 covers the driving elements 73, the first wires 74, and the second wires 75, as well as parts of the substrate 1 and the wiring substrate 71. The sealing resin 76 has electrical insulation properties. The sealing resin 76 is, for example, a black, soft synthetic resin used for underfill. Alternatively, the sealing resin 76 may be a black, hard synthetic resin.

[0039] As shown in Figs. 1 and 4, the connector 77 is mounted on one end of the wiring board 71 in the y direction. The connector 77 is connected to the thermal printer B10. The connector 77 has a plurality of pins (not shown). Some of the plurality of pins are electrically connected to wiring (not shown) on the wiring board 71 to which a plurality of second wires 75 are joined. Furthermore, another portion of the plurality of pins are electrically connected to wiring (not shown) on the wiring board 71 that is electrically connected to the base 411 of the common wiring 41.

[0040] Next, an example of a manufacturing method for the thermal printhead A10 will be described with reference to Figures 12 to 25. Here, the cross-sectional positions of Figures 12 to 15 and Figures 20 to 25 are the same as the cross-sectional position of Figure 5, which shows the main part of the thermal printhead A10.

[0041] First, as shown in FIGS. 12 to 14, a mask layer 89 is formed on a substrate 81. The substrate 81 is made of a semiconductor material. The semiconductor material includes a single crystal material containing silicon. The substrate 81 is a silicon wafer. In a direction perpendicular to the z direction, a plurality of regions corresponding to a plurality of substrates 1 are connected together to form 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 in opposite directions in the z direction. The surface orientations of the first surface 81A and the second surface 81B based on the crystal structure of the substrate 81 are both (100) surfaces. 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.

[0042] First, as shown in Fig. 12, a second mask layer 892 is formed. To form the second mask layer 892, a thin film of silicon nitride or a thin film of silicon dioxide is formed by low pressure CVD (Chemical Vapor Deposition) to cover the entire surface of the base material 81. Then, the thin film covering the first surface 81A of the base material 81 is removed by wet etching using hydrofluoric acid (HF). This forms the second mask layer 892.

[0043] Next, as shown in Fig. 13 and Fig. 14, a first mask layer 891 is formed. To form the first mask layer 891, as shown in Fig. 13, a thin film of silicon nitride or a thin film of silicon dioxide is formed by plasma CVD to cover the entire first surface 81A of the substrate 81. The temperature at which the thin film covering the substrate 81 is formed by plasma CVD is lower than the temperature at which the thin film covering the substrate 81 is formed by reduced pressure CVD. Thereafter, as shown in Fig. 14, a part of the thin film covering the first surface 81A is removed by lithography patterning and reactive ion etching (RIE). As a result, the first mask layer 891 is formed.

[0044] FIG. 16 shows a state after the first mask layer 891 is formed on the first surface 81A of the base material 81. As shown in FIG. 16, the first mask layer 891 has a covering portion 891A, two first openings 891B, and a second opening 891C. The covering portion 891A extends in the x direction and covers the first surface 81A. The two first openings 891B are positioned with the covering portion 891A therebetween in the y direction and extend in the x direction. The second opening 891C is positioned next to the end of the covering portion 891A in the x direction and is connected to the two first openings 891B. The first surface 81A is exposed from the two first openings 891B and the second opening 891C.

[0045] Next, as shown in FIG. 15, the main surface 11 and the convex portion 13 are formed on the base material 81 by anisotropic etching, and then the mask layer 89 is removed. The main surface 11 faces the same direction as the first surface 81A of the base material 81 in the z direction, and is located between the first surface 81A and the second surface 81B of the base material 81. The convex portion 13 protrudes from the main surface 11 in the z direction and extends in the x direction. The main surface 11 and the convex portion 13 are formed on the base material 81 by performing anisotropic etching on the first surface 81A exposed from the two first openings 891B of the first mask layer 891 and the second opening 891C of the first mask layer 891. The etching liquid used for the 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. As described above, the main surface 11 and the convex portion 13 are formed on the base material 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 covering 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 inclination angles α of the first inclined surface 131 and the second inclined surface 132 of the protrusion 13 with respect to the main surface 11 are equal to each other.

[0046] 17 and 18 show the state of the base material 81 after the main surface 11 and the convex portion 13 are formed on the base material 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 convex portion 13 are formed by performing anisotropic etching on 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 convex portion 13 are formed by performing anisotropic etching on the first surface 81A exposed from the second openings 891C of the first mask layer 891. At this time, the portions of the covering portion 891A of the first mask layer 891 located on the third inclined surface 133 and the fourth inclined surface 134 are removed. Furthermore, a part of the top surface 130 of the convex portion 13 is exposed from the first mask layer 891. This is because the part is dissolved in the etching solution used for the anisotropic etching. A thin film of silicon nitride and a thin film of silicon dioxide are more easily dissolved in the etching solution when formed by plasma CVD than when formed by low pressure CVD. Therefore, the first mask layer 891 is more easily dissolved in the etching solution than the second mask layer 892. As shown in FIG. 18, the surface roughness of each of the third inclined surface 133 and the fourth inclined surface 134 is greater than the surface roughness of each of the first inclined surface 131 and the second inclined surface 132. In FIG. 18, the third inclined surface 133 and the fourth inclined surface 134 located behind the cross section shown in the figure are each shown by a region with multiple points.

[0047] FIG. 19 also shows the state of the base material 81 after the main surface 11 and the convex portion 13 are formed on the base material 81 by anisotropic etching and before the mask layer 89 is removed. However, the manufacturing method of the first mask layer 891 is different from the manufacturing method of the first mask layer 891 shown in FIG. 17. The first mask layer 891 is formed by low-pressure CVD like the second mask layer 892. This makes the first mask layer 891 less soluble in the etching solution than the first mask layer 891 shown in FIG. 17. Therefore, 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 convex portion 13 is not removed. Therefore, even if the properties of the first mask layer 891 are equivalent to the properties of the second mask layer 892, the third inclined surface 133 and the fourth inclined surface 134 are formed on the convex portion 13.

[0048] 20, an insulating layer 21 is formed to cover the main surface 11 and the protrusions 13 of the substrate 81. The insulating layer 21 is formed by laminating thin films of silicon dioxide formed by plasma CVD using tetraethyl orthosilicate (TEOS) as a raw material gas multiple times.

[0049] Next, as shown in Figs. 21 to 23, a resistor layer 3 and a wiring layer 4 are formed. The resistor layer 3 includes a plurality of heat generating portions 31 arranged in the x direction. The wiring layer 4 is electrically connected to the plurality of heat generating portions 31. Furthermore, the step of forming the wiring layer 4 includes a step of forming a common wiring 41 and a plurality of individual wirings 42. In the base material 81, the common wiring 41 is located on one side in the y direction with respect to the plurality of heat generating portions 31 of the resistor layer 3 shown in Fig. 13. In the base material 81, the plurality of individual wirings 42 are located on the other side in the y direction with respect to the plurality of heat generating portions 31 shown in Fig. 13.

[0050] 21, a resistor film 82 is formed on the main surface 11 and the protrusions 13 of a substrate 81. The resistor film 82 is formed so as to cover the entire surface of the insulating layer 21. The resistor film 82 is formed by laminating a thin film of tantalum nitride on the insulating layer 21 by a sputtering method.

[0051] 22, a conductive layer 83 is formed to cover the entire surface of the resistor film 82. The conductive layer 83 is formed by laminating a thin copper film multiple times on the resistor film 82 by a sputtering method. Alternatively, the conductive layer 83 may be formed by laminating a thin titanium film on the resistor film 82 by a sputtering method, and then laminating a thin copper film multiple times on the thin titanium film by a sputtering method.

[0052] Next, as shown in FIG. 23, lithographic patterning is performed on the conductive layer 83, and then a part of the conductive layer 83 is removed. The removal is performed by wet etching using a mixed solution of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). As a result, the common wiring 41 and a plurality of individual wirings 42 are formed in contact with the resistor film 82. At the same time, the region of the resistor film 82 formed on the top surface 130 of the protrusion 13 of the substrate 81 is exposed from the wiring layer 4. Thereafter, lithographic patterning is performed on the resistor film 82 and the wiring layer 4, and then a part of the resistor film 82 is removed. The removal is performed by reactive ion etching. As a result, the resistor layer 3 is formed on the main surface 11 and the protrusion 13 of the substrate 81. A plurality of heating parts 31 appear on the top surface 130 of the substrate 81.

[0053] 24, a protective layer 5 is formed to cover a part of the main surface 11 of the base material 81, the plurality of heat generating portions 31 of the resistor layer 3, and the wiring layer 4. The protective layer 5 is formed by laminating thin films of silicon nitride by plasma CVD.

[0054] Next, as shown in FIG. 25, a wiring opening 51 penetrating in the z direction is formed in the protective layer 5. The wiring opening 51 is formed by removing a part of the protective layer 5 after lithographic patterning is performed on the protective layer 5. The removal is performed by reactive ion etching. As a result, a part of the individual wirings 42 (the bases 421 of the individual wirings 42 and a part of each of the extensions 422 of the individual wirings 42 shown in FIG. 5) is exposed from the wiring opening 51. The part of each of the individual wirings 42 exposed from the wiring opening 51 forms the base 421 to which the first wires 74 are individually bonded by, for example, wire bonding. A metal layer such as gold may be laminated by plating on the part of each of the individual wirings 42 exposed from the wiring opening 51 (including the bases 421).

[0055] Next, the substrate 81 is cut in the thickness direction along the x and y directions. The individual pieces obtained in this way become the main parts of the thermal printhead A10 including the substrate 1. A dicing saw is an example of a device for cutting the substrate 81. The cutting line of the substrate 81 is set at a position away from the protruding parts 13 of the substrate 81. This prevents the blade of the cutting device from coming into contact with the protruding parts 13.

[0056] Next, a plurality of driving elements 73 and a connector 77 are mounted on the wiring board 71. Next, the rear surface 12 of the substrate 1 and the wiring board 71 are bonded to the heat dissipation member 72. Next, a plurality of first wires 74 and a plurality of second wires 75 are bonded to the wiring board 71. Finally, a sealing resin 76 that covers the driving elements 73, the plurality of first wires 74, and the plurality of second wires 75 is formed on the substrate 1 and the wiring board 71. Through the above steps, the thermal printhead A10 is obtained.

[0057] Next, the function and effect of the thermal printhead A10 will be described.

[0058] The thermal printhead A10 has a main surface 11 and a protruding portion 13, and is provided with a substrate 1 containing a semiconductor material. The protruding portion 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 on at least one of both ends of the protruding portion 13 in the x direction. The third inclined surface 133 is inclined with respect to the main surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined with respect to the main surface 11 and the second inclined surface 132. As a result, the end surface of the protruding portion 13 located at at least one of both ends of the protruding portion 13 in the x direction and connected to the main surface 11, the first inclined surface 131, and the second inclined surface 132 is composed of the third inclined surface 133 and the fourth inclined surface 134. The end faces do not rise steeply from the main surface 11 along the y and z directions, but are inclined with respect to the main surface 11, the first inclined surface 131, and the second inclined surface 132. Therefore, with the thermal printhead A10, it is possible to prevent the ends of the protrusions 13 in the x direction from becoming sharp.

[0059] In the manufacture of the thermal printhead A10, a step of forming a mask layer 89 on the first surface 81A and the second surface 81B of the substrate 81 is included before the step of forming the main surface 11 and the protrusions 13 on the substrate 81 by anisotropic etching. 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 covering portion 891A, two first openings 891B, and a second opening 891C. The first surface 81A is exposed from the two first openings 891B and the second opening 891C. This allows the formation of the protrusions 13 having a third inclined surface 133 and a fourth inclined surface 134 in addition to the top surface 130, the first inclined surface 131, and the second inclined surface 132.

[0060] The first mask layer 891 is more soluble in an etching solution used for anisotropic etching than the second mask layer 892. As a result, as shown in Fig. 16, the portions 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 convex portion 13 are removed by anisotropic etching. This allows the mask layer 89 to be removed more efficiently after the main surface 11 and the convex portion 13 are formed on the base material 81.

[0061] 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 with respect to the top surface 130. As a result, the intersection angles of the third inclined surface 133 and the fourth inclined surface 134 with respect to the top surface 130 are both obtuse angles. This makes it possible to prevent the third edge 130C and the fourth edge 130D, which form the boundaries between the third inclined surface 133 and the fourth inclined surface 134 and the top surface 130, from becoming sharp.

[0062] 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 approach 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 multiple heat generating parts 31 of the resistor layer 3 in the x direction. Therefore, the contact area of ​​the end of the recording medium in the x direction with the thermal printhead A10 becomes smaller. This leads to suppression of damage to the recording medium caused by contact with the thermal printhead A10.

[0063] The semiconductor material contained in the substrate 1 includes a single crystal material composed of silicon, which allows the cost of the substrate 1 to be reduced while the thermal conductivity of the substrate 1 is relatively high (approximately 170 W / (m K)).

[0064] The substrate 1 has protrusions 13 protruding in the z direction from the main surface 11. The multiple heat generating portions 31 of the resistor layer 3 are formed on the protrusions 13. This makes it possible to transfer heat from the multiple heat generating portions 31 to the recording medium while minimizing the contact area of ​​the recording medium with the thermal printhead A10 when printing on the recording medium shown in Fig. 4. This improves the quality of printing on the recording medium.

[0065] The thermal printhead A10 further includes a protective layer 5 that covers both the multiple heat generating portions 31 of the resistor layer 3 and the wiring layer 4. This not only protects the multiple heat generating portions 31 and the wiring layer 4 with the protective layer 5, but also makes it easier for a recording medium to come into contact with the thermal printhead A10 when the thermal printhead A10 is in use.

[0066] The thermal printhead A10 further includes a heat dissipation member 72. The rear surface 12 of the substrate 1 is joined to the heat dissipation member 72. This allows a portion of the heat generated from the multiple heat generating parts 31 to be rapidly dissipated to the outside via the substrate 1 and the heat dissipation member 72 when the thermal printhead A10 is in use.

[0067] Second Embodiment A thermal printhead A20 according to a fifth embodiment of the present disclosure will be described with reference to Figures 26 and 27. In these figures, elements that are the same as or similar to those of the thermal printhead A10 described above are given the same reference numerals, and duplicated explanations will be omitted. Here, the cross-sectional position of Figure 26 is the same as the cross-sectional position of Figure 5, which shows the main parts of the thermal printhead A10.

[0068] The thermal printhead A20 differs from the thermal printhead A10 in that it further comprises a glaze layer 22.

[0069] As shown in Figs. 26 and 27, the glaze layer 22 is located between the top surface 130 of the protrusion 13 and the insulating layer 21. The glaze layer 22 contains, for example, amorphous glass. Therefore, the glaze layer 22 is made of a material containing glass. The linear expansion coefficient of the glaze layer 22 is approximately the same as the linear expansion coefficient of the substrate 1. As shown in Fig. 27, the glaze layer 22 bulges in the z direction toward the side toward which the top surface 130 faces. 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.

[0070] Next, an example of a method for manufacturing the thermal printhead A20 will be described with reference to Figure 28. Here, the cross-sectional position of Figure 25 is the same as that of Figure 5, which shows the main part of the thermal printhead A10.

[0071] Among the manufacturing steps of the main part of the thermal printhead A10 described above, after the steps of forming the main surface 11 and the protrusions 13 on the base material 81 shown in Figs. 15 to 19 and removing the mask layer 89, the glaze layer 22 is formed in contact with the top surface 130 of the protrusions 13 as shown in Fig. 28. The glaze layer 22 is formed by supplying a glaze material, which is a fluid, to the top surface 130 and then baking the glaze material. The glaze material is discharged, for example, by a dispenser. The glaze material includes glass such as amorphous glass. The glaze material may be applied in multiple layers. Another example of a method of supplying the glaze material is a method of printing the glaze material on the top surface 130 using a screen. After the glaze layer 22 is formed, the thermal printhead A20 is obtained by going through the same steps as those shown in Figs. 20 to 25 among the manufacturing steps of the main part of the thermal printhead A10 described above.

[0072] Next, the function and effect of the thermal printhead A20 will be described.

[0073] The thermal printhead A20 has a main surface 11 and a protruding portion 13, and is provided with a substrate 1 containing a semiconductor material. The protruding portion 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 on at least one of both ends of the protruding portion 13 in the x direction. The third inclined surface 133 is inclined with respect to the main surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined with respect to the main surface 11 and the second inclined surface 132. Therefore, the thermal printhead A20 can also prevent the end of the protruding portion 13 in the x direction from becoming sharp. Furthermore, the thermal printhead A20 has a configuration in common with the thermal printhead A10, and thereby exerts the same effects as the thermal printhead A10.

[0074] The thermal printhead A20 further includes a glaze layer 22 located between the top surfaces 130 of the protrusions 13 and the insulating layer 21. The glaze layer 22 bulges in the z direction toward the side toward which the top surfaces 130 face. This configuration makes it possible to reduce the contact area of ​​the thermal printhead A20 with the recording medium while suppressing the size of the protrusions 13. Furthermore, the glaze layer 22 has the effect of storing heat generated by the multiple heat generating parts 31. Therefore, the thermal printhead A20 can improve the quality of printing on the recording medium performed by the multiple heat generating parts 31 while improving printing energy efficiency.

[0075] Third Embodiment A thermal printhead A30 according to a third embodiment of the present disclosure will be described with reference to Figures 29 and 30. In these figures, elements that are the same as or similar to those of the thermal printhead A10 described above are given the same reference numerals, and duplicated explanations will be omitted. Here, the cross-sectional position of Figure 29 is the same as the cross-sectional position of Figure 5, which shows the main parts of the thermal printhead A10.

[0076] In the thermal printhead A30, the configuration of the protrusions 13 of the substrate 1 and the configuration of the plurality of heat generating portions 31 of the resistor layer 3 are different from those of the thermal printhead A10.

[0077] As shown in FIGS. 29 and 30, the convex portion 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 convex portion 13, and are inclined with respect to the main surface 11 and the top surface 130 of the substrate 1. The fifth inclined surface 135 is located on the side where the first inclined surface 131 of the convex portion 13 is located in the y direction. The sixth inclined surface 136 is located on the side where the second inclined surface 132 of the convex portion 13 is located in the y direction. The fifth inclined surface 135 and the sixth inclined surface 136 approach each other from the main surface 11 toward the top surface 130.

[0078] As shown in Fig. 30, the inclination angles γ of the fifth inclined surface 135 and the sixth inclined surface 136 with respect to the main surface 11 are equal to each other. The inclination angle γ of the fifth inclined surface 135 is smaller than the inclination angle α of the first inclined surface 131 with respect 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 with respect to the main surface 11. The fifth inclined surface 135 and the sixth inclined surface 136 can be formed by carrying out the following process between the process shown in Fig. 15 and the process shown in Fig. 20 in the manufacture of the thermal printhead A10. This process involves wet etching using an aqueous solution of tetramethylammonium hydroxide (TMAH) at 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.

[0079] 30, the multiple heat generating portions 31 of the resistor 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 multiple heat generating portions 31 may be formed on the top surface 130, the fifth inclined surface 135 and the first inclined surface 131 of the protrusion 13.

[0080] Next, the function and effect of the thermal printhead A30 will be described.

[0081] The thermal printhead A30 has a main surface 11 and a protruding portion 13, and is provided with a substrate 1 containing a semiconductor material. The protruding portion 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 on at least one of both ends of the protruding portion 13 in the x direction. The third inclined surface 133 is inclined with respect to the main surface 11 and the first inclined surface 131. The fourth inclined surface 134 is inclined with respect to the main surface 11 and the second inclined surface 132. Therefore, the thermal printhead A30 can also prevent the end of the protruding portion 13 in the x direction from becoming sharp. Furthermore, the thermal printhead A30 has a configuration in common with the thermal printhead A10, and thereby exerts the same effects as the thermal printhead A10.

[0082] In the thermal printhead A30, the convex portion 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 convex portion 13 and are inclined with respect 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 with respect 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 with respect to the main surface 11. By adopting this configuration, the shape of a part of the wiring layer 4 formed along the convex portion 13 becomes smoother. In addition, the occurrence of defects and breaks in the wiring pattern in the wiring layer 4 formed along the convex portion 13 is suppressed.

[0083] The present disclosure is not limited to the above-described embodiment. The specific configuration of each part of the present disclosure can be freely designed in various ways.

[0084] The technical configurations of the thermal printhead and the manufacturing method thereof provided by the present disclosure are described below. [Appendix 1] A substrate including a semiconductor material and having a main surface facing a thickness direction and a protrusion protruding from the main surface and extending in a main scanning direction; a resistor layer including a plurality of heat generating portions arranged in the main scanning direction and positioned on the protruding portions; a wiring layer that is electrically connected to the plurality of heat generating portions and is formed in contact with the resistor layer, the protrusion has a top surface facing the thickness direction and positioned away from the main surface, and a first inclined surface and a second inclined surface connected to the main surface and positioned away from each other in the sub-scanning direction and inclined with respect to the main surface; 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 are formed on at least one of both end portions of the convex portion in the main scanning direction, the third inclined surface is inclined with respect to the main surface and the first inclined surface, A thermal printhead, wherein the fourth inclined surface is inclined with respect to the main surface and the second inclined surface. [Appendix 2] The area of ​​the third inclined surface is smaller than the area of ​​the first inclined surface, 2. The thermal printhead of claim 1, wherein an area of ​​the fourth inclined surface is smaller than an area of ​​the second inclined surface. [Appendix 3] the first inclined surface and the second inclined surface approach each other from the main surface toward the top surface, 3. The thermal printhead of claim 2, wherein the third inclined surface and the fourth inclined surface become closer to each other from the main surface toward the top surface. [Appendix 4] the first inclined surface and the second inclined surface are connected to the top surface and are inclined with respect to the top surface, 4. The thermal printhead of claim 3, wherein the third inclined surface and the fourth inclined surface are connected to the top surface and are inclined with respect to the top surface. [Appendix 5] a periphery of the top surface includes a first edge that forms a boundary with the first inclined surface, a second edge that forms a boundary with the second inclined surface, a third edge that forms a boundary with the third inclined surface, and a fourth edge that forms a boundary with the fourth inclined surface; the third edge is inclined with respect to the first edge in the main scanning direction, 5. The thermal printhead of claim 4, wherein the fourth edge is inclined relative to the second edge in the main scanning direction. [Appendix 6] 6. The thermal printhead of claim 5, wherein the third edge and the fourth edge approach each other as they move away from the first edge and the second edge in the main scanning direction. [Appendix 7] the protrusion has a fifth inclined surface and a sixth inclined surface that are connected to the top surface and are inclined with respect to the main surface and the top surface, the fifth inclined surface is located on the side where the first inclined surface is located in the sub-scanning direction, the sixth inclined surface is located on the side where the second inclined surface is located in the sub-scanning direction, the fifth inclined surface and the sixth inclined surface approach each other from the main surface toward the top surface, an inclination angle of the fifth inclined surface with respect to the main surface is smaller than an inclination angle of the first inclined surface with respect to the main surface, 4. The thermal printhead of claim 3, wherein an angle of inclination of the sixth inclined surface with respect to the main surface is smaller than an angle of inclination of the second inclined surface with respect to the main surface. [Appendix 8] 8. The thermal printhead according to claim 3, wherein the third inclined surface and the fourth inclined surface are connected to each other in the sub-scanning direction. [Appendix 9] 9. The thermal printhead of claim 8, wherein a ridge line that forms a boundary between the third inclined surface and the fourth inclined surface is inclined with respect to the main surface. [Appendix 10] 10. The thermal printhead of claim 9, wherein, when viewed along the thickness direction, the ridge line is positioned outward in the main scanning direction from the top surface. [Appendix 11] the third inclined surface has a surface roughness greater than that of the first inclined surface; 11. The thermal printhead of claim 3, wherein the fourth inclined surface has a surface roughness greater than a surface roughness of the second inclined surface. [Appendix 12] further comprising an insulating layer covering the main surface and the protrusion, 12. A thermal printhead as described in any one of claims 1 to 11, wherein the insulating layer is located between the substrate and the resistor layer. [Appendix 13] the wiring layer includes a common wiring and a plurality of individual wirings; the common wiring is electrically connected to the plurality of heat generating portions, 13. The thermal printhead according to claim 1, wherein the individual wirings are individually connected to the heat generating portions. [Appendix 14] 14. The thermal printhead of claim 1, further comprising a protective layer covering the plurality of heat generating portions and the wiring layer. [Appendix 15] the substrate has a back surface facing the opposite side to the main surface in the thickness direction, Further comprising a heat dissipation member, 15. The thermal printhead according to claim 1, wherein the rear surface is joined to the heat dissipation member. [Appendix 16] A substrate having a first surface and a second surface facing opposite to each other in a thickness direction and including a semiconductor material, forming a mask layer on the first surface and the second surface; forming, on the base material by anisotropic etching, a main surface that faces the same direction as the first surface in the thickness direction and is located between the first surface and the second surface, and a convex portion that protrudes from the main surface; removing the mask layer; forming a resistor layer including a plurality of heat generating portions arranged in a main scanning direction on the protruding portion; forming a wiring layer that is electrically connected to the plurality of heat generating portions in contact with the resistor layer; 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 covering portion extending in the main scanning direction and covering the first surface, two first openings positioned on either side of the covering portion in the sub-scanning direction and extending in the main scanning direction, and a second opening positioned adjacent to an end of the covering portion in the main scanning direction and connected to the two first openings, The method for manufacturing a thermal printhead, wherein the first surface is exposed from the two first openings and the second opening. [Appendix 17] 17. The method for manufacturing a thermal printhead described in claim 16, wherein the first mask layer is more soluble than the second mask layer in an etching solution used for the anisotropic etching. [Appendix 18] the first mask layer is formed by plasma CVD; The method for manufacturing a thermal printhead described in Appendix 17, wherein the second mask layer is formed by low-pressure CVD. [Explanation of symbols]

[0085] A10, A20: Thermal print head B10: Thermal printer 1: Substrate 11: Main surface 12: Back side 13: Convex 130:Top surface 130A: First edge 130B: Second Edge 130C: Third Edge 130D: 4th edge 131:First slope 132:Second slope 133: Third slope 134: 4th slope 135: Fifth slope 136: 6th slope 139: Ridgeline 21: Insulating layer 22: Glaze layer 3: Resistor layer 31: Heating part 4: Wiring layer 41: Common wiring 411: Base 412: Extension part 42: Individual wiring 421: Base 422: Extension part 5:Protective layer 51: Wiring opening 71: Wiring board 72: Heat dissipation material 73: Drive element 74: First wire 75: 2nd wire 76: Sealing resin 77: Connector 79: Platen roller 81: Base material 81A: Side 1 81B: 2nd side 82:Resistor membrane 83: Conductive layer 89: Mask layer 891: First mask layer 891A: Covering part 891B: 1st opening 891C: 2nd opening 892: Second mask layer α, β1, β2, γ: Tilt angles

Claims

1. A substrate including a semiconductor material and having a main surface facing a thickness direction and a protrusion protruding from the main surface and extending in a main scanning direction; a resistor layer including a plurality of heat generating portions arranged in the main scanning direction and positioned on the protruding portions; a wiring layer that is electrically connected to the plurality of heat generating portions and is formed in contact with the resistor layer, the protrusion has a top surface facing the thickness direction and positioned away from the main surface, and a first inclined surface and a second inclined surface connected to the main surface and positioned away from each other in the sub-scanning direction and inclined with respect to the main surface; 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 are formed on at least one of both end portions of the convex portion in the main scanning direction, the third inclined surface is inclined with respect to the main surface and the first inclined surface, The fourth inclined surface is inclined with respect to the main surface and the second inclined surface.

2. The area of ​​the third inclined surface is smaller than the area of ​​the first inclined surface, The thermal printhead of claim 1 , wherein an area of ​​the fourth inclined surface is smaller than an area of ​​the second inclined surface.

3. the first inclined surface and the second inclined surface approach each other from the main surface toward the top surface, The thermal printhead of claim 2 , wherein the third inclined surface and the fourth inclined surface approach each other from the main surface toward the top surface.

4. the first inclined surface and the second inclined surface are connected to the top surface and are inclined with respect to the top surface, The thermal printhead of claim 3 , wherein the third inclined surface and the fourth inclined surface are connected to the top surface and inclined relative to the top surface.

5. a periphery of the top surface includes a first edge that forms a boundary with the first inclined surface, a second edge that forms a boundary with the second inclined surface, a third edge that forms a boundary with the third inclined surface, and a fourth edge that forms a boundary with the fourth inclined surface; the third edge is inclined with respect to the first edge in the main scanning direction, The thermal printhead of claim 4 , wherein 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 approach each other as they move away from the first edge and the second edge in the main scanning direction.

7. the protrusion has a fifth inclined surface and a sixth inclined surface that are connected to the top surface and are inclined with respect to the main surface and the top surface, the fifth inclined surface is located on a side on which the first inclined surface is located in the sub-scanning direction, the sixth inclined surface is located on a side on which the second inclined surface is located in the sub-scanning direction, the fifth inclined surface and the sixth inclined surface approach each other from the main surface toward the top surface, an inclination angle of the fifth inclined surface with respect to the main surface is smaller than an inclination angle of the first inclined surface with respect to the main surface, The thermal printhead according to claim 3 , wherein an inclination angle of the sixth inclined surface with respect to the main surface is smaller than an inclination angle of the second inclined surface with respect to the main surface.

8. 8. The thermal printhead according to claim 3, wherein the third inclined surface and the fourth inclined surface are connected to each other in the sub-scanning direction.

9. The thermal printhead according to claim 8 , wherein a ridgeline that defines a boundary between the third inclined surface and the fourth inclined surface is inclined with respect to the main surface.

10. The thermal printhead according to claim 9 , wherein the ridge line is positioned outward in the main scanning direction from the top surface when viewed along the thickness direction.

11. the third inclined surface has a surface roughness greater than that of the first inclined surface; 11. The thermal printhead according to claim 3, wherein the fourth inclined surface has a surface roughness greater than that of the second inclined surface.

12. further comprising an insulating layer covering the main surface and the protrusion, 12. A thermal printhead according to claim 1, wherein the insulating layer is located between the substrate and the resistor layer.

13. the wiring layer includes a common wiring and a plurality of individual wirings; the common wiring is electrically connected to the plurality of heat generating portions, 13. A thermal printhead according to claim 1, wherein the plurality of individual wirings are individually connected to the plurality of heat generating portions.

14. 14. The thermal printhead according to claim 1, further comprising a protective layer covering the plurality of heat generating portions and the wiring layer.

15. the substrate has a back surface facing the opposite side to the main surface in the thickness direction, Further comprising a heat dissipation member, 15. The thermal printhead according to claim 1, wherein the rear surface is joined to the heat dissipation member.

16. A substrate having a first surface and a second surface facing opposite each other in a thickness direction and including a semiconductor material, forming a mask layer on the first surface and the second surface; forming, on the base material by anisotropic etching, a main surface that faces the same direction as the first surface in the thickness direction and is located between the first surface and the second surface, and a convex portion that protrudes from the main surface; removing the mask layer; forming a resistor layer including a plurality of heat generating portions arranged in a main scanning direction on the protruding portion; forming a wiring layer that is electrically connected to the plurality of heat generating portions in contact with the resistor layer; 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 covering portion extending in the main scanning direction and covering the first surface, two first openings positioned on either side of the covering portion in the sub-scanning direction and extending in the main scanning direction, and a second opening positioned adjacent to an end of the covering portion in the main scanning direction and connected to the two first openings, The first surface is exposed through the two first openings and the second opening.

17. The method for manufacturing a thermal printhead according to claim 16 , wherein the first mask layer is more soluble in an etching solution used for the anisotropic etching than the second mask layer.

18. The first mask layer is formed by plasma CVD; The method for manufacturing a thermal printhead according to claim 17, wherein the second mask layer is formed by low pressure CVD.

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