Method for manufacturing a thermal print head

Abstract

To provide a thermal print head and a manufacturing method thereof in which interference with a platen roller is prevented, while improving print quality.SOLUTION: A thermal print head A10 comprises: a substrate 1 having a main surface 11 and a protrusion 13, and containing a semiconductor material; a resistor layer 3 including a plurality of heating parts 31 positioned on the protrusion 13; and a wiring layer 4 conducting to the plurality of heating parts 31 and formed in contact with the resistor layer 3. The protrusion 13 has a top face 130, a first inclined plane 131 and a second inclined plane 132. The first inclined plane 131 and the second inclined plane 132 are interposed between the main surface 11 and the top face 130, positioned spaced away from each other in a sub-scanning direction, and are inclined relative to the main surface 11. A first inclination angle α1 of the first inclined plane 131 relative to the main surface 11, and a second inclination angle α2 of the second inclined plane 132 relative to the main surface 11 are both 55° or greater.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to Of the thermal printhead a manufacturing method.

Background Art

[0002] Patent Document 1 discloses a thermal print head including a substrate made of a material containing silicon. The substrate of the thermal print head has a main surface and a convex portion that extends in the main scanning direction and protrudes from the main surface. As shown in FIG. 6 of Patent Document 1 and the like, a plurality of heat generating portions are arranged in the main scanning direction on the convex portion. According to such a configuration, since the recording medium can be accurately brought into contact with the convex portion on which the plurality of heat generating portions are arranged, an improvement in printing quality can be expected. Further, the substrate of the thermal print head has the advantages of relatively high thermal conductivity and lower cost than a substrate made of a material containing aluminum nitride. However, when attempting to miniaturize the thermal print head, there is a risk that a platen roller for pressing the recording medium against the thermal print head may interfere with the thermal print head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above circumstances, an object of the present disclosure is to provide a thermal print head and a manufacturing method thereof that can prevent interference with a platen roller while improving printing quality.

Means for Solving the Problems

[0005] The thermal printhead provided by the first aspect of the present disclosure has a main surface facing in the thickness direction, and a convex portion protruding from the main surface and extending in the main scanning direction. The thermal printhead further includes a substrate containing a semiconductor material, a resistor layer including a plurality of heating portions arranged in the main scanning direction and located on the convex portion, and a wiring layer formed in conduction with the plurality of heating portions and in contact with the resistor layer. The convex portion has a top surface, a first inclined surface, and a second inclined surface. The top surface faces in the thickness direction and is located away from the main surface. The first inclined surface and the second inclined surface are interposed between the main surface and the top surface, are spaced apart from each other in the sub-scanning direction, and are inclined with respect to the main surface. The first inclined surface and the second inclined surface approach each other as they extend from the main surface toward the top surface. The first inclination angle of the first inclined surface with respect to the main surface and the second inclination angle of the second inclined surface with respect to the main surface are both 55° or more.

[0006] A method for manufacturing a thermal printhead provided by the second aspect of the present disclosure includes forming, in a base material having a first surface and a second surface facing opposite sides in the thickness direction and containing a semiconductor material, a main surface facing the same side 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 and extending in the main scanning direction; forming a resistor layer including a plurality of heating portions arranged in the main scanning direction on the convex portion; and forming a wiring layer in conduction with the plurality of heating portions in contact with the resistor layer. The step of forming the main surface and the convex portion includes forming a plurality of groove portions in the base material, the groove portions being recessed from the first surface, extending in the main scanning direction, and arranged along the sub-scanning direction. The plurality of groove portions are interposed between the main surface and the first surface, are spaced apart from each other in the sub-scanning direction, and have a pair of first inclined surfaces inclined with respect to the main surface in a direction away from each other as they extend from the main surface toward the first surface. In the step of forming the plurality of groove portions, a part of the base material is removed by a blade.

Advantages of the Invention

[0007] According to the thermal print head and its manufacturing method according to the present disclosure, it is possible to prevent interference with the platen roller while improving print quality.

[0008] Other features and advantages of the present disclosure will become clearer from the following detailed description based on the accompanying drawings.

Brief Description of the Drawings

[0009]

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MODE FOR CARRYING OUT THE INVENTION

[0010] A mode for carrying out the present disclosure will be described with reference to the accompanying drawings.

[0011] 〔First Embodiment〕 Based on FIGS. 1 to 6, the thermal print head A10 according to the first embodiment of the present disclosure will be described. The thermal print head A10 forms the main part of the thermal printer B10 described later. The thermal print head A10 is composed of a main part and an accessory part. The main part of the thermal print head A10 includes a substrate 1, an insulating layer 2, a resistor layer 3, a wiring layer 4, and a protective layer 5. The accessory part of the thermal print head A10 includes a wiring board 71, a heat dissipation member 72, a plurality of drive elements 73, a plurality of first wires 74, a plurality of second wires 75, a sealing resin 76, and a connector 77. Here, in FIG. 1, for convenience of understanding, the illustration of the protective layer 5 and the plurality of first wires 74, the plurality of second wires 75, and the sealing resin 76 is omitted. In FIGS. 2 and 3, for convenience of understanding, the protective layer 5 is transparent.

[0012] Here, for convenience of explanation, the main scanning direction of the thermal print head A10 is referred to as the "x direction". The sub-scanning direction of the thermal print head 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, "viewed along the z direction" refers to "viewed along the thickness direction".

[0013] In the thermal print head A10, as shown in FIG. 4, the substrate 1 forming the main part of the thermal print head A10 is joined to the heat dissipation member 72. Further, the wiring board 71 is located next to the substrate 1 in the y direction. The wiring board 71 is fixed to the heat dissipation member 72 in the same manner as the substrate 1. On the substrate 1, a plurality of heating portions 31 (details will be described later) that form a part of the resistor layer 3 and are arranged in the x direction are formed. The plurality of heating portions 31 selectively generate heat by a plurality of drive elements 73 mounted on the wiring board 71. The plurality of drive elements 73 are driven according to a printing signal transmitted from the outside via the connector 77.

[0014] Furthermore, as shown in FIG. 4, the thermal printer B10 according to the present disclosure includes a thermal print head A10 and a platen roller 79. In the thermal printer B10, the platen roller 79 is a roller-shaped mechanism that feeds a recording medium such as thermal paper. When the platen roller 79 presses the recording medium against the plurality of heat generating portions 31, the plurality of heat generating portions 31 print on the recording medium. In the thermal printer B10, instead of the platen roller 79, a mechanism that is not roller-shaped can be adopted. The mechanism has a flat surface. Here, the flat surface includes a curved surface having a small curvature. In the thermal printer B10, both the roller-shaped mechanism such as the platen roller 79 and the mechanism are referred to as a "platen".

[0015] As shown in FIG. 1, the substrate 1 is rectangular and extends 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 contains a semiconductor material. The semiconductor material includes a single crystal material composed of silicon (Si).

[0016] As shown in FIG. 5, the substrate 1 has a main surface 11 and a back surface 12 that face opposite sides in the z direction. The surface 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 print head A10, the main surface 11 faces the platen roller 79, and the back surface 12 faces the wiring board 71.

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

[0018] As shown in FIG. 5, the convex portion 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 in the z direction and is located away from the main surface 11. The top surface 130 is a flat surface with the x direction and the y direction as in-plane directions. The first inclined surface 131 and the second inclined surface 132 are interposed between the main surface 11 and the top surface 130 in the z direction and are located away from each other in the y direction. 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 go from the main surface 11 toward the top surface 130.

[0019] In FIG. 6, the first inclination angle α1 of the first inclined surface 131 with respect to the main surface 11 is 55° or more and 88° or less. The first inclination angle α1 refers to the acute angle among the intersection angles of the virtual base plane B and the virtual inclined plane S1. The virtual base plane B is a plane with the x direction and the y direction as in-plane directions. The virtual base plane B is parallel to the top surface 130. The virtual inclined plane S1 is a plane passing through both ends of the first inclined surface 131 located in the z direction.

[0020] In FIG. 6, the second inclination angle α2 of the second inclined surface 132 with respect to the main surface 11 is 55° or more and 80° or less. The second inclination angle α2 refers to the acute angle among the intersection angles of the virtual base plane B and the virtual inclined plane S1. The virtual inclined plane S2 is a plane passing through both ends of the second inclined surface 132 located in the z direction.

[0021] As shown in FIG. 6, the surface roughness of each of the first inclined surface 131 and the second inclined surface 132 is larger than the surface roughness of the top surface 130. Furthermore, the surface roughness of the main surface 11 is also larger than the surface roughness of the top surface 130.

[0022] As shown in FIGS. 5 and 6, the insulating layer 2 covers the main surface 11 and the convex portion 13 of the substrate 1. Due to the insulating layer 2, the substrate 1 is electrically insulated from the resistor layer 3 and the wiring layer 4. The insulating layer 2 is made of, for example, silicon dioxide (SiO2) using tetraethyl orthosilicate (TEOS) as a raw material. An example of the thickness of the insulating layer 2 is 1 μm or more and 15 μm or less.

[0023] As shown in FIGS. 5 and 6, the resistor layer 3 is formed on the main surface 11 of the substrate 1 and the convex portion 13. The resistor layer 3 is in contact with the insulating layer 2. Thereby, in the thermal print head A10, the insulating layer 2 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 0.02 μm or more and 0.1 μm or less.

[0024] As shown in FIGS. 2, 3, and 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 portions exposed from the wiring layer 4. By selectively energizing the plurality of heat generating portions 31 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 spaced apart from each other. The plurality of heat generating portions 31 are formed in contact with the insulating layer 2. In the thermal print head 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 in the y direction of the top surface 130. As shown in FIG. 4, in the thermal printer B10, the plurality of heat generating portions 31 face the platen roller 79.

[0025] As shown in FIGS. 5 and 6, the wiring layer 4 is formed in contact with the resistor layer 3. The wiring layer 4 forms a conductive path for energizing the plurality of heat generating portions 31 of the resistor layer 3. The electrical resistivity of the wiring layer 4 is smaller than the electrical resistivity 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. In addition, the wiring layer 4 may be composed of two metal layers, a titanium (Ti) layer laminated on the resistor layer 3 and a copper layer laminated on the titanium layer. An example of the thickness of the titanium layer in this case 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.

[0026] As shown in FIG. 2, the wiring layer 4 includes a common wiring 41 and a plurality of individual wirings 42. The common wiring 41 is located on one side in the y direction with respect to the plurality of heating portions 31 of the resistor layer 3. The plurality of individual wirings 42 are located on the opposite side of the common wiring 41 with the plurality of heating portions 31 interposed therebetween in the y direction. As shown in FIG. 3, when viewed along the z direction, the 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 heating portions 31.

[0027] As shown in FIGS. 2 and 3, the common wiring 41 has a base portion 411 and a plurality of extending portions 412. In the y direction, the base portion 411 is located farthest from the plurality of heating portions 31 of the resistor layer 3. The base portion 411 is in a strip shape extending in the x direction when viewed along the z direction. The plurality of extending portions 412 are in a strip shape extending from the end portion of the base portion 411 facing the convex portion 13 of the substrate 1 in the y direction toward the plurality of heating portions 31. The plurality of extending portions 412 are arranged along the x direction. A part of each of the plurality of extending portions 412 is formed on the second inclined surface 132 of the convex portion 13. In the common wiring 41, current flows from the base portion 411 through the plurality of extending portions 412 to the plurality of heating portions 31.

[0028] As shown in FIGS. 2 and 3, each of the plurality of individual wirings 42 has a base portion 421 and an extending portion 422. In the y direction, the base portion 421 is located farthest from the plurality of heating portions 31 of the resistor layer 3. The base portions 421 of the plurality of individual wirings 42 are arranged at equal intervals so as to be staggeredly arranged with respect to the x direction.

[0029] As shown in FIGS. 2 and 3, the extending portion 422 is in a strip shape extending from the end of the base portion 421 facing the convex portion 13 of the substrate 1 in the y direction toward the plurality of heating portions 31. The extending portions 422 of the plurality of individual wirings 42 are arranged along the x direction. The extending portion 422 of each of the plurality of individual wirings 42 is formed on the first inclined surface 131 of the convex portion 13. In each of the plurality of individual wirings 42, current flows from any one of the plurality of heating portions 31 through the extending portion 422 to the base portion 421. When viewed along the z direction, each of the plurality of heating portions 31 is sandwiched between any one of the extending portions 422 of the plurality of individual wirings 42 and any one of the plurality of extending portions 412 of the common wiring 41. The configuration of the wiring layer 4 and the plurality of heating portions 31 shown in FIGS. 2 and 3 is an example. The configuration of the wiring layer 4 and the plurality of heating portions 31 in the present disclosure is not limited to the configuration shown in FIGS. 2 and 3.

[0030] As shown in FIG. 5, the protective layer 5 covers a part of the main surface 11 of the substrate 1, the plurality of heating portions 31 of the resistor layer 3, and the wiring layer 4. The protective layer 5 has electrical insulation. The protective layer 5 contains silicon in its composition. The protective layer 5 is made of, for example, any one of silicon dioxide, silicon nitride (Si3N4), and silicon carbide (SiC). Alternatively, the protective layer 5 may be a laminate composed of a plurality of these substances. 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 region of the protective layer 5 covering the plurality of heating portions 31 by the platen roller 79 shown in FIG. 4.

[0031] As shown in FIG. 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 plurality of individual wirings 42 and a part of each of the extending portions 422 of the plurality of individual wirings 42 are exposed.

[0032] As shown in FIG. 4, the wiring board 71 is positioned adjacent to the substrate 1 in the y direction. As shown in FIG. 1, when viewed along the z direction, a plurality of individual wirings 42 are positioned between the plurality of heat generating portions 31 of the resistor layer 3 and the wiring board 71 in the y direction. When viewed along the z direction, the area of the wiring board 71 is larger than the area of the substrate 1. Further, when 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 (Printed Circuit Board) substrate. A plurality of drive elements 73 and connectors 77 are mounted on the wiring board 71.

[0033] As shown in FIG. 4, the heat radiating member 72 faces the back surface 12 of the substrate 1. The back surface 12 is joined to the heat radiating member 72. The wiring board 71 is fixed to the heat radiating member 72 by fastening members such as screws. During the use of the thermal print head A10, part of the heat generated from the plurality of heat generating portions 31 of the resistor layer 3 is conducted to the heat radiating member 72 through the substrate 1. The heat conducted to the heat radiating member 72 is radiated to the outside. The heat radiating member 72 is made of, for example, aluminum (Al).

[0034] As shown in FIGS. 1 and 4, the plurality of drive elements 73 are mounted on the wiring board 71 via an electrically insulating die bonding material (not shown). Each of the plurality of drive elements 73 is a semiconductor element in which various circuits are configured. One end of each of the plurality of first wires 74 and one end of each of the plurality of second wires 75 are joined to each of the plurality of drive elements 73. The other ends of the plurality of first wires 74 are 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 a wiring (not shown) provided on the wiring board 71 and electrically connected to the connector 77. Thereby, a printing signal, a control signal, and a voltage supplied to the plurality of heat generating portions 31 of the resistor layer 3 are input from the outside to the plurality of drive elements 73 via the connector 77. The plurality of drive elements 73 selectively apply a voltage to the plurality of individual wirings 42 based on these electrical signals. Thereby, the plurality of heat generating portions 31 selectively generate heat.

[0035] As shown in FIG. 4, 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 part of each 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 and soft synthetic resin used for underfill. Alternatively, the sealing resin 76 may be a black and hard synthetic resin.

[0036] As shown in FIGS. 1 and 4, the connector 77 is mounted on one end of the wiring substrate 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). A part of the plurality of pins is electrically connected to a wiring (not shown) to which the plurality of second wires 75 are joined on the wiring substrate 71. Further, another part of the plurality of pins is electrically connected to a wiring (not shown) that is electrically connected to the base portion 411 of the common wiring 41 on the wiring substrate 71.

[0037] Next, with reference to FIGS. 7 to 15, an example of the manufacturing method of the thermal print head A10 will be described. Here, the positions in FIGS. 7 and 10 to 15 are the same as the position in FIG. 5 showing the main part of the thermal print head A10.

[0038] First, as shown in FIG. 7, a main surface 11 and a plurality of convex portions 13 are formed on a base material 81. The base material 81 is made of a semiconductor material. The semiconductor material includes a single crystal material having a composition of silicon. The base material 81 is a silicon wafer. In a direction orthogonal to the z direction, a plurality of regions corresponding to the plurality of substrates 1 are connected in series, which corresponds to the base material 81. The base material 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 second surface 81B corresponds to the back surface 12 of the substrate 1. The surface orientations of the first surface 81A and the second surface 81B based on the crystal structure of the base material 81 are both (100) planes. The main surface 11 faces the same side as the first surface 81A in the z direction and is located between the first surface 81A and the second surface 81B. The plurality of convex portions 13 protrude in the z direction from the main surface 11 and extend in the x direction. The plurality of convex portions 13 are arranged along the y direction.

[0039] As shown in FIG. 7, in the step of forming the main surface 11 and the plurality of convex portions 13 on the base material 81, the step of forming a plurality of groove portions 811 in the base material 81 is included. The plurality of groove portions 811 are recessed from the first surface 81A of the base material 81, extend in the x direction, and are arranged along the y direction. The plurality of groove portions 811 have a pair of first inclined surfaces 811A. The pair of first inclined surfaces 811A are interposed between the main surface 11 and the first surface 81A in the z direction. The pair of first inclined surfaces 811A are located apart from each other in the y direction. The pair of first inclined surfaces 811A are inclined with respect to the main surface 11 in a direction in which they are farther apart from each other from the main surface 11 toward the first surface 81A.

[0040] As shown in FIG. 7, in the step of forming the plurality of groove portions 811 in the base material 81, a part of the base material 81 is removed by the blade 88. The blade 88 is pressed against the first surface 81A of the base material 81. Thereby, the plurality of groove portions 811 are formed in the base material 81. The blade 88 is a so-called dicing blade. As shown in FIG. 8, the blade 88 has an end surface 881 and a pair of tapered surfaces 882. The end surface 881 faces the radial direction r of the blade 88. The pair of tapered surfaces 882 are connected to the end surface 881 and are located apart from each other in the rotation axis direction N of the blade 88. The pair of tapered surfaces 882 are inclined with respect to the end surface 881 in a direction in which they are farther apart from each other from the end surface 881 toward the rotation axis of the blade 88. The inclination angle γ of each of the pair of tapered surfaces 882 with respect to the end surface 881 is 55° or more and 80° or less.

[0041] FIG. 9 shows the state of the base material 81 in which the plurality of groove portions 811 are formed. By forming the plurality of groove portions 811 in the base material 81, the base material 81 in which the main surface 11 and the plurality of convex portions 13 are formed is obtained. One of the pair of first inclined surfaces 811A of the pair of first inclined surfaces 811A becomes the first inclined surface 131 of any one of the plurality of convex portions 13. The other of the pair of first inclined surfaces 811A of the pair of first inclined surfaces 811A becomes the second inclined surface 132 of any one of the plurality of convex portions 13. The first surface 81A of the base material 81 remaining with the formation of the plurality of groove portions 811 becomes the top surface 130 of the plurality of convex portions 13.

[0042] Next, as shown in FIG. 10, an insulating layer 2 that covers the main surface 11 and the plurality of convex portions 13 of the base material 81 is formed. The insulating layer 2 is formed by laminating a plurality of times a thin film of silicon dioxide formed by plasma CVD (Chemical Vapor Deposition) using tetraethyl orthosilicate (TEOS) as a source gas.

[0043] Next, as shown in FIGS. 11 to 13, a resistor layer 3 and a wiring layer 4 are formed. The resistor layer 3 includes a plurality of heating portions 31 arranged in the x direction. The wiring layer 4 is electrically connected to the plurality of heating portions 31. Further, 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 heating 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 heating portions 31 shown in FIG. 13.

[0044] First, as shown in FIG. 11, a resistor film 82 is formed on the main surface 11 and the plurality of convex portions 13 of the base material 81. The resistor film 82 is formed so as to cover the entire surface of the insulating layer 2. The resistor film 82 is formed by laminating a thin film of tantalum nitride on the insulating layer 2 by a sputtering method.

[0045] Next, as shown in FIG. 12, a conductive layer 83 that covers the entire surface of the resistor film 82 is formed. The conductive layer 83 is formed by laminating a thin film of copper on the resistor film 82 a plurality of times by a sputtering method. Alternatively, in forming the conductive layer 83, a method may be adopted in which a thin film of titanium is laminated on the resistor film 82 by a sputtering method, and then a thin film of copper is laminated on the thin film of titanium a plurality of times by a sputtering method.

[0046] Next, as shown in FIG. 13, after performing lithographic patterning on the conductive layer 83, 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). Thereby, the common wiring 41 and the 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 surfaces 130 of the plurality of convex portions 13 of the base material 81 is exposed from the wiring layer 4. Thereafter, after performing lithographic patterning on the resistor film 82 and the wiring layer 4, a part of the resistor film 82 is removed. The removal is performed by reactive ion etching. Thereby, the resistor layer 3 is formed on the main surface 11 of the base material 81 and the plurality of convex portions 13. A plurality of heating portions 31 appear on the top surface 130 of the base material 81.

[0047] Next, as shown in FIG. 14, a protective layer 5 is formed to cover a part of the main surface 11 of the base material 81, the plurality of heating portions 31 of the resistor layer 3, and the wiring layer 4. The protective layer 5 is formed by laminating a thin film of silicon nitride by plasma CVD.

[0048] Next, as shown in FIG. 15, a wiring opening 51 penetrating in the z direction is formed in the protective layer 5. The wiring opening 51 is formed by performing lithographic patterning on the protective layer 5 and then removing a part of the protective layer 5. The removal is performed by reactive ion etching. Thereby, a part of each of the plurality of individual wirings 42 (a part of the base portions 421 of the plurality of individual wirings 42 shown in FIG. 5 and a part of each of the extending portions 422 of the plurality of individual wirings 42) is exposed from the wiring opening 51. A part of each of the plurality of individual wirings 42, which is exposed from the wiring opening 51, forms a base portion 421 to which a plurality of first wires 74 are individually joined, for example, by wire bonding. A metal layer such as gold may be laminated by plating on each part (including the base portion 421) of the plurality of individual wirings 42 exposed from the wiring opening 51.

[0049] Next, the base material 81 is cut along the x-direction and the y-direction. The individual pieces thus obtained become the main part of the thermal print head A10 including the substrate 1. As an example of a cutting device for the base material 81, a dicing saw can be mentioned. The cutting line of the base material 81 is set at a position away from the resistor layer 3 and the wiring layer 4.

[0050] Next, a plurality of drive elements 73 and connectors 77 are mounted on the wiring board 71. Next, the back surface 12 of the substrate 1 and the wiring board 71 are joined to the heat dissipation member 72. Next, a plurality of first wires 74 and a plurality of second wires 75 are joined to the wiring board 71. Finally, a sealing resin 76 that covers the drive element 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 print head A10 is obtained.

[0051] <Modification Example of the First Embodiment> Next, based on FIG. 16, a thermal print head A11, which is a modification example of the thermal print head A10, will be described. Here, the position in FIG. 16 is the same as the position in FIG. 6 showing the main part of the thermal print head A10.

[0052] The thermal print head A11 differs from the thermal print head A10 in the configuration of the main surface 11 and the convex portion 13 of the substrate 1. As shown in FIG. 16, the surface roughness of each of the main surface 11, the first inclined surface 131, and the second inclined surface 132 of the convex portion 13 is about the same as the surface roughness of the top surface 130 of the convex portion 13. That is, the main surface 11, the first inclined surface 131, and the second inclined surface 132 are all flat surfaces. This configuration can be obtained by adjusting the conditions for forming the thin film that serves as the base of the insulating layer 2 when using plasma CVD in the step of forming the insulating layer 2 shown in FIG. 10 in the manufacturing method of the thermal print head A10 described above. When the surface roughness of each of the main surface 11, the first inclined surface 131, and the second inclined surface 132 is relatively large, the surface roughness of each of these surfaces may be reduced in advance by wet etching using a potassium hydroxide (KOH) solution or the like as a pre-step of the step shown in FIG. 10.

[0053] Next, the operation and effect of the thermal print head A10 will be described.

[0054] The thermal print head A10 has a main surface 11 and a convex portion 13, and includes a substrate 1 containing a semiconductor material. The convex portion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. The first inclined surface 131 and the second inclined surface 132 are interposed between the main surface 11 and the top surface 130 and are inclined with respect to the main surface 11. The first inclination angle α1 of the first inclined surface 131 with respect to the main surface 11 and the second inclination angle α2 of the second inclined surface 132 with respect to the main surface 11 are both 55° or more.

[0055] The above-described configuration is obtained by forming a plurality of groove portions 811 in the base material 81 by removing a part of the base material 81 with a blade 88 in the process of forming the main surface 11 and the convex portion 13 on the base material 81 in the manufacturing process of the thermal print head A10. According to this manufacturing method, compared with the case of forming a plurality of groove portions 811 by wet etching using a potassium hydroxide solution or the like, a plurality of groove portions 811 can be formed in a shorter time and more efficiently. As a result, since the height H of the convex portion 13 shown in FIG. 6 can be set higher, it is possible to prevent the platen roller 79 shown in FIG. 4 from interfering with the thermal print head A10. Therefore, according to the thermal print head A10, it is possible to improve the printing quality and prevent interference with the platen roller 79.

[0056] The first inclination angle α1 of the first inclined surface 131 and the second inclination angle α2 of the second inclined surface 132 are both 80° or less. Thereby, it is possible to suppress the contact of the recording medium with the thermal print head A10 from becoming sharp in the z direction. Therefore, it is possible to prevent damage to the recording medium.

[0057] The surface roughness of each of the first inclined surface 131 and the second inclined surface 132 is larger than the surface roughness of the top surface 130. Further, the surface roughness of the main surface 11 of the substrate 1 is larger than the surface roughness of the top surface 130. This configuration is a trace that appears when a plurality of groove portions 811 are formed in the base material 81 by removing a part of the base material 81 with the blade 88 in the manufacture of the thermal print head A10.

[0058] The thermal print head A10 further includes an insulating layer 2 that covers the main surface 11 and the convex portion 13 of the substrate 1. The insulating layer 2 is interposed between the substrate 1 and the resistor layer 3. Thereby, even if the surface roughness of each of the main surface 11, the first inclined surface 131, and the second inclined surface 132 is relatively large, the surface of the insulating layer 2 becomes smooth, so that the thickness of the resistor layer 3 becomes uniform. Therefore, variations in electrical resistance in the resistor layer 3 are suppressed. Further, an anchoring effect (anchor effect) is exhibited in the insulating layer 2 with respect to the substrate 1. Thereby, the bonding strength of the insulating layer 2 to the substrate 1 can be improved.

[0059] The semiconductor material contained in the substrate 1 includes a single crystal material having a composition of silicon. Thereby, while the thermal conductivity of the substrate 1 is made relatively large (about 170 W / (m·K)), the cost of the substrate 1 can be reduced.

[0060] The thermal print head A10 further includes a protective layer 5 that covers the plurality of heat generating portions 31 of the resistor layer 3 and the wiring layer 4. Thereby, the plurality of heat generating portions 31 and the wiring layer 4 are protected by the protective layer 5, and when the thermal print head A10 is used, the contact of the recording medium with the thermal print head A10 becomes smoother.

[0061] The thermal print head A10 further includes a heat radiating member 72. The back surface 12 of the substrate 1 is joined to the heat radiating member 72. Thereby, when the thermal print head A10 is used, a part of the heat generated from the plurality of heat generating portions 31 can be quickly released to the outside through the substrate 1 and the heat radiating member 72.

[0062] 〔Second Embodiment〕 Based on FIGS. 17 and 18, the thermal print head A20 according to the second embodiment of the present disclosure will be described. In these figures, elements that are the same as or similar to the above-described thermal print head A10 are denoted by the same reference numerals, and redundant descriptions are omitted. Here, the position in FIG. 17 is the same as the position in FIG. 5 showing the main part of the thermal print head A10.

[0063] In the thermal print head A20, the configuration of the convex portion 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 corresponding components of the thermal print head A10.

[0064] As shown in FIG. 17, the convex portion 13 has a third inclined surface 133. The third inclined surface 133 is located on the same side of the top surface 130 as the first inclined surface 131 in the y direction, and is interposed between the first inclined surface 131 and the top surface 130 in the z direction. The third inclined surface 133 is inclined with respect to the main surface 11. As shown in FIG. 18, the third inclination angle α3 of the third inclined surface 133 with respect to the main surface 11 is smaller than the first inclination angle α1. The third inclination angle α3 refers to the acute angle among the intersection angles of the virtual base plane B and the third inclined surface 133.

[0065] As shown in FIG. 18, the surface roughness of the first inclined surface 131 is larger than the surface roughness of the third inclined surface 133. However, the surface roughness of the first inclined surface 131 is smaller than the surface roughness of the first inclined surface 131 of the convex portion 13 of the thermal print head A10. The dimension h1 of the first inclined surface 131 in the z direction is larger than the dimension h2 of the third inclined surface 133 in the z direction.

[0066] As shown in FIG. 17, the convex portion 13 has a fourth inclined surface 134. The fourth inclined surface 134 is located on the opposite side of the third inclined surface 133 with the top surface 130 interposed therebetween in the y direction, and is interposed between the second inclined surface 132 and the top surface 130 in the z direction. The fourth inclined surface 134 is inclined with respect to the main surface 11. The third inclined surface 133 and the fourth inclined surface 134 approach each other from the first inclined surface 131 and the second inclined surface 132 toward the top surface 130. As shown in FIG. 18, the fourth inclination angle α4 of the fourth inclined surface 134 with respect to the main surface 11 is smaller than the second inclination angle α2. The fourth inclination angle α4 refers to the acute angle among the intersection angles of the virtual base surface B and the fourth inclined surface 134.

[0067] As shown in FIG. 18, the surface roughness of the second inclined surface 132 is larger than the surface roughness of the fourth inclined surface 134. However, the surface roughness of the second inclined surface 132 is smaller than the surface roughness of the second inclined surface 132 of the convex portion 13 of the thermal print head A10. Further, the surface roughness of the main surface 11 is smaller than the surface roughness of the main surface 11 of the thermal print head A10.

[0068] As shown in FIG. 18, the plurality of heating portions 31 of the resistor layer 3 are formed on the top surface 130, the fourth inclined surface 134, and the second inclined surface 132 of the convex portion 13. In addition, the plurality of heating portions 31 may be formed on the top surface 130, the third inclined surface 133, and the first inclined surface 131 of the convex portion 13.

[0069] Next, with reference to FIGS. 19 to 24, an example of the manufacturing method of the thermal print head A20 will be described. Here, the positions in FIGS. 19 to 22 are the same as the positions in FIG. 5 showing the main part of the thermal print head A10.

[0070] In the process of manufacturing the thermal print head A20, in the process of forming the main surface 11 and the plurality of convex portions 13 on the base material 81, before the process of forming the plurality of groove portions 811 on the base material 81, it includes the process of forming the first mask layer 891 and the plurality of second mask layers 892 on the base material 81 shown in FIGS. 19 and 20. However, the process of forming the first mask layer 891 and the plurality of second mask layers 892 may be omitted. Further, in the process of forming the main surface 11 and the plurality of convex portions 13 on the base material 81, after the process of forming the plurality of groove portions 811 on the base material 81, it includes the process of forming a pair of second inclined surfaces 811B on two adjacent groove portions 811 among the plurality of groove portions 811 shown in FIG. 22.

[0071] First, as shown in FIG. 19, a first mask layer 891 covering the first surface 81A and the second surface 81B of the base material 81 is formed. When forming the first mask layer 891, either a thin film of silicon nitride covering the entire surface of the base material 81 or a thin film of silicon dioxide is formed by plasma CVD.

[0072] Next, as shown in FIG. 20, a plurality of second mask layers 892 covering the first surface 81A of the base material 81 are formed. The plurality of second mask layers 892 are formed by subjecting a part of the first mask layer 891 to lithographic patterning and reactive ion etching (RIE) with respect to the first mask layer 891 covering the first surface 81A. Thereby, the plurality of second mask layers 892 are formed. The plurality of second mask layers 892 extend in the x direction and are arranged along the y direction.

[0073] Next, as shown in FIG. 21, a plurality of groove portions 811 are formed on the base material 81. In this process, any one of the plurality of groove portions 811 is formed between two adjacent second mask layers 892 among the plurality of second mask layers 892. When forming the plurality of groove portions 811, the blade 88 is prevented from contacting the plurality of second mask layers 892. FIG. 23 shows the state of the base material 81 on which the plurality of groove portions 811 are formed.

[0074] Next, as shown in FIG. 22, a pair of second inclined surfaces 811B are formed in two adjacent groove portions 811 among the plurality of groove portions 811. The pair of second inclined surfaces 811B are formed by performing wet etching using an aqueous solution of tetramethylammonium hydroxide (TMAH) at the boundary between the pair of first inclined surfaces 811A of the plurality of groove portions 811 and the first surface 81A. The pair of second inclined surfaces 811B are interposed between the pair of first inclined surfaces 811A and the first surface 81A in the z direction. The pair of second inclined surfaces 811B are inclined with respect to the main surface 11 in a direction approaching each other from the pair of first inclined surfaces 811A toward the first surface 81A.

[0075] FIG. 24 shows a state of the base material 81 in which a pair of second inclined surfaces 811B are formed in two adjacent groove portions 811 among the plurality of groove portions 811. By forming the pair of second inclined surfaces 811B, the base material 81 on which the main surface 11 and the plurality of convex portions 13 are formed is obtained. One of the pair of second inclined surfaces 811B becomes the third inclined surface 133 of any one of the plurality of convex portions 13. The other of the pair of second inclined surfaces 811B becomes the fourth inclined surface 134 of any one of the plurality of convex portions 13. When forming the pair of second inclined surfaces 811B, wet etching is also performed on the main surface 11 and the pair of first inclined surfaces 811A of the plurality of groove portions 811. As a result, the surface roughness of each of the main surface 11 of the thermal print head A20 and the first inclined surface 131 and the second inclined surface 132 of the convex portion 13 becomes smaller than the surface roughness of those surfaces of the thermal print head A10.

[0076] After forming the main surface 11 and the plurality of convex portions 13 on the base material 81, the first mask layer 891 and the plurality of second mask layers 892 are removed. These are removed by wet etching using hydrofluoric acid (HF).

[0077] The subsequent steps for manufacturing the thermal print head A20 are the same as the manufacturing steps of the thermal print head A10 shown in FIGS. 10 to 15. By going through the above steps, the thermal print head A20 is obtained.

[0078] Next, the operation and effect of the thermal print head A20 will be described.

[0079] The thermal print head A20 has a main surface 11 and a convex portion 13, and includes a substrate 1 containing a semiconductor material. The convex portion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. The first inclined surface 131 and the second inclined surface 132 are interposed between the main surface 11 and the top surface 130 and are inclined with respect to the main surface 11. The first inclination angle α1 of the first inclined surface 131 with respect to the main surface 11 and the second inclination angle α2 of the second inclined surface 132 with respect to the main surface 11 are both 55° or more. Therefore, even with the thermal print head A20, it is possible to prevent interference with the platen roller 79 while improving the printing quality. Further, the thermal print head A20 has a configuration common to the thermal print head A10, and thus exhibits the same operation and effect as the thermal print head A10.

[0080] The thermal print head A20 has a third inclined surface 133 and a fourth inclined surface 134. The third inclined surface 133 and the fourth inclined surface 134 are interposed between the first inclined surface 131 and the second inclined surface 132 and the top surface 130 and are inclined with respect to the main surface 11. The third inclination angle α₃ of the third inclined surface 133 with respect to the main surface 11 is smaller than the first inclination angle α₁ of the first inclined surface 131. The fourth inclination angle α₄ of the fourth inclined surface 134 with respect to the main surface 11 is smaller than the second inclination angle α₂ of the second inclined surface 132. By adopting this configuration, a part of the shape of the wiring layer 4 formed along the convex portion 13 becomes smoother. At the same time, in the wiring layer 4 formed along the convex portion 13, the occurrence of defects and disconnections in the wiring pattern is suppressed.

[0081] 〔Third Embodiment〕 Based on FIG. 25, the thermal print head A30 according to the third embodiment of the present disclosure will be described. In this figure, the same or similar elements as those of the thermal print head A10 described above are denoted by the same reference numerals, and redundant descriptions are omitted. Here, the position in FIG. 25 is the same as the position in FIG. 6 showing the main part of the thermal print head A10.

[0082] In the thermal print head A30, the configuration of the convex portion 13 of the substrate 1 is different from that of the corresponding portion of the thermal print head A10.

[0083] As shown in FIG. 25, the convex portion 13 has a fifth inclined surface 135. The fifth inclined surface 135 is located on the same side as the first inclined surface 131 with respect to the top surface 130 in the y direction, and is interposed between the first inclined surface 131 and the third inclined surface 133 in the z direction. The fifth inclined surface 135 is inclined with respect to the main surface 11. The fifth inclination angle α5 of the fifth inclined surface 135 with respect to the main surface 11 is larger than the third inclination angle α3 and smaller than the first inclination angle α1. The fifth inclination angle α5 refers to the acute angle among the intersection angles of the virtual base plane B and the fifth inclined surface 135.

[0084] As shown in FIG. 25, the convex portion 13 has a sixth inclined surface 136. The sixth inclined surface 136 is located on the opposite side of the fifth inclined surface 135 across the top surface 130 in the y direction, and is interposed between the second inclined surface 132 and the fourth inclined surface 134 in the z direction. The sixth inclined surface 136 is inclined with respect to the main surface 11. The fifth inclined surface 135 and the sixth inclined surface 136 approach each other from the first inclined surface 131 and the second inclined surface 132 toward the third inclined surface 133 and the fourth inclined surface 134. The sixth inclination angle α6 of the sixth inclined surface 136 with respect to the main surface 11 is larger than the fourth inclination angle α4 and smaller than the second inclination angle α2. The sixth inclination angle α6 refers to the acute angle among the intersection angles of the virtual base plane B and the sixth inclined surface 136.

[0085] As shown in FIG. 25, the surface roughness of the fifth inclined surface 135 is smaller than that of the first inclined surface 131. The surface roughness of the sixth inclined surface 136 is smaller than that of the second inclined surface 132. The dimension h1 of the first inclined surface 131 in the z direction is larger than each of the dimension h2 of the third inclined surface 133 and the dimension h3 of the fifth inclined surface 135 in the z direction.

[0086] Next, the operation and effect of the thermal print head A30 will be described.

[0087] The thermal print head A30 has a main surface 11 and a convex portion 13, and includes a substrate 1 containing a semiconductor material. The convex portion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. The first inclined surface 131 and the second inclined surface 132 are interposed between the main surface 11 and the top surface 130 and are inclined with respect to the main surface 11. Both the first inclination angle α1 of the first inclined surface 131 with respect to the main surface 11 and the second inclination angle α2 of the second inclined surface 132 with respect to the main surface 11 are 55° or more. Therefore, even with the thermal print head A30, it is possible to prevent interference with the platen roller 79 while improving the printing quality. Furthermore, the thermal print head A30 has a configuration common to the thermal print head A10, and thus exhibits the same operational effects as the thermal print head A10.

[0088] In the thermal print head A30, there are a fifth inclined surface 135 and a sixth inclined surface 136. The fifth inclined surface 135 and the sixth inclined surface 136 are interposed between the first inclined surface 131 and the second inclined surface 132 and the third inclined surface 133 and the fourth inclined surface 134, and are inclined with respect to the main surface 11. The fifth inclination angle α5 of the fifth inclined surface 135 with respect to the main surface 11 is larger than the third inclination angle α3 of the third inclined surface 133 and smaller than the first inclination angle α1 of the first inclined surface 131. The sixth inclination angle α6 of the sixth inclined surface 136 with respect to the main surface 11 is larger than the fourth inclination angle α4 of the fourth inclined surface 134 and smaller than the second inclination angle α2 of the second inclined surface 132. By adopting this configuration, the shape of a part of the wiring layer 4 formed along the convex portion 13 becomes smoother than in the case of the thermal print head A20. Therefore, in the wiring layer 4 formed along the convex portion 13, the occurrence of defects and disconnections in the wiring pattern is more effectively suppressed.

[0089] The present disclosure is not limited to the above-described embodiments. The specific configuration of each part of the present disclosure can be freely designed and changed in various ways.

[0090] The technical configuration of the thermal print head and its manufacturing method provided by the present disclosure is appended below. [Appendix 1] A substrate that has a main surface facing in the thickness direction, and a convex portion that protrudes from the main surface and extends in the main scanning direction, and includes a semiconductor material; A resistor layer including a plurality of heat generating portions arranged in the main scanning direction and located on the convex portion; A wiring layer that is electrically connected to the plurality of heat generating portions and is formed in contact with the resistor layer. The convex portion has a top surface, a first inclined surface, and a second inclined surface. The top surface faces in the thickness direction and is located away from the main surface. The first inclined surface and the second inclined surface are interposed between the main surface and the top surface, are located apart from each other in the sub-scanning direction, and are inclined with respect to the main surface. The first inclined surface and the second inclined surface approach each other as they go from the main surface toward the top surface. A thermal print head in which a first inclination angle of the first inclined surface with respect to the main surface and a second inclination angle of the second inclined surface with respect to the main surface are both 55° or more. [Appendix 2] The thermal print head according to Appendix 1, wherein the first inclination angle and the second inclination angle are both 80° or less. [Appendix 3] The convex portion has a third inclined surface that is located on the same side as the first inclined surface with respect to the top surface in the sub-scanning direction, is interposed between the first inclined surface and the top surface, and is inclined with respect to the main surface. The thermal print head according to Appendix 1 or 2, wherein a third inclination angle of the third inclined surface with respect to the main surface is smaller than the first inclination angle. [Appendix 4] The thermal print head according to Appendix 3, wherein a surface roughness of the first inclined surface is larger than a surface roughness of the third inclined surface. [Appendix 5] The thermal print head according to Appendix 4, wherein a dimension of the first inclined surface in the thickness direction is larger than a dimension of the third inclined surface in the thickness direction. [Appendix 6] The convex portion is located on the side opposite to the third inclined surface with the top surface interposed therebetween in the sub-scanning direction, and is interposed between the second inclined surface and the top surface, and has a fourth inclined surface inclined with respect to the main surface. The thermal print head according to supplementary note 4 or 5, wherein a fourth inclination angle of the fourth inclined surface with respect to the main surface is smaller than the second inclination angle. [Supplementary note 7] The thermal print head according to supplementary note 6, wherein a surface roughness of the second inclined surface is larger than a surface roughness of the fourth inclined surface. [Supplementary note 8] The convex portion is located on the same side as the first inclined surface with respect to the top surface in the sub-scanning direction, and is interposed between the first inclined surface and the third inclined surface, and has a fifth inclined surface inclined with respect to the main surface. The thermal print head according to supplementary note 6 or 7, wherein a fifth inclination angle of the fifth inclined surface with respect to the main surface is larger than the third inclination angle and smaller than the first inclination angle. [Supplementary note 9] The thermal print head according to any one of supplementary notes 1 to 8, wherein a surface roughness of each of the first inclined surface and the second inclined surface is larger than a surface roughness of the top surface. [Supplementary note 10] The thermal print head according to supplementary note 9, wherein a surface roughness of the main surface is larger than a surface roughness of the top surface. [Supplementary note 11] The thermal print head further includes an insulating layer covering the main surface and the convex portion. The thermal print head according to any one of supplementary notes 1 to 10, wherein the insulating layer is interposed between the substrate and the resistor layer. [Supplementary note 12] The wiring layer includes a common wiring and a plurality of individual wirings. The common wiring is electrically connected to the plurality of heating portions. The thermal print head according to any one of supplementary notes 1 to 11, wherein the plurality of individual wirings are individually electrically connected to the plurality of heating portions. [Supplementary note 13] The thermal print head according to any one of Appendices 1 to 12, further comprising a protective layer covering the plurality of heat generating portions and the wiring layer. [Appendix 14] Further comprising a heat dissipation member, The substrate has a back surface facing the opposite side to the main surface in the thickness direction, The back surface is joined to the heat dissipation member. The thermal print head according to any one of Appendices 1 to 13. [Appendix 15] In a base material having a first surface and a second surface facing opposite sides in the thickness direction and including a semiconductor material, a main surface facing the same side 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 and extending in the main scanning direction are formed; Forming a resistor layer including a plurality of heat generating portions arranged in the main scanning direction on the convex portion; Forming a wiring layer electrically connected to the plurality of heat generating portions in contact with the resistor layer. In the step of forming the main surface and the convex portion, the step of forming a plurality of groove portions recessed from the first surface, extending in the main scanning direction, and arranged along the sub-scanning direction in the base material is included. The plurality of groove portions are interposed between the main surface and the first surface, are spaced apart from each other in the sub-scanning direction, and have a pair of first inclined surfaces inclined with respect to the main surface in a direction of being spaced apart from each other as they go from the main surface toward the first surface. In the step of forming the plurality of groove portions, a part of the base material is removed by a blade. A method for manufacturing a thermal print head. [Appendix 16] The blade has an end surface facing the radial direction of the blade, and a pair of tapered surfaces connected to the end surface and spaced apart from each other in the rotation axis direction of the blade. The pair of tapered surfaces are inclined with respect to the end surface in a direction of being spaced apart from each other as they go from the end surface toward the rotation axis of the blade. The manufacturing method of the thermal print head according to appended note 15, wherein the inclination angle of each of the pair of tapered surfaces with respect to the end surface is 55° or more and 80° or less. [Appended note 17] In the step of forming the main surface and the convex portion, after the step of forming the plurality of groove portions, a step of forming a pair of second inclined surfaces that are interposed between the pair of first inclined surfaces and the first surface and are inclined with respect to the main surface is included in two adjacent groove portions among the plurality of groove portions. The manufacturing method of the thermal print head according to appended note 16, wherein the pair of second inclined surfaces are formed by wet etching. [Appended note 18] In the step of forming the main surface and the convex portion, before the step of forming the plurality of groove portions, a step of forming a plurality of mask layers that extend in the main scanning direction, are arranged along the sub-scanning direction, and cover the first surface is included. In the step of forming the plurality of groove portions, any one of the plurality of groove portions is formed between two adjacent mask layers among the plurality of mask layers. The manufacturing method of the thermal print head according to appended note 17.

Explanation of reference numerals

[0091] A10, A20, A30: Thermal print head B10: Thermal printer 1: Substrate 11: Main surface 12: Back surface 13: Convex portion 130: Top surface 131: First inclined surface 132: Second inclined surface 133: Third inclined surface 134: Fourth inclined surface 135: Fifth inclined surface 136: Sixth inclined surface 21: Insulating layer 22: Glaze layer 3: Resistor layer 31: Heat generating portion 4: Wiring layer 41: Common wiring 411: Base 412: Extended portion 42: Individual wiring 421: Base portion 422: Extended portion 5: Protective layer 51: Wiring opening 71: Wiring substrate 72: Heat dissipation member 73: Driving element 74: First wire 75: Second wire 76: Encapsulating resin 77: Connector 79: Platen roller 81: Substrate 81A: First surface 81B: Second surface 811: Groove portion 811A: First inclined surface 811B: Second inclined surface 82: Resistive film 83: Conductive layer 88: Blade 881: End face 882: Tapered surface 891: First mask layer 892: Second mask layer α1~α6: First inclination angle to Sixth inclination angle H: Height h1, h2, h3: Dimensions γ: Inclination angle

Claims

Claims 1. A method of manufacturing a thermal print head, comprising: forming a substrate having a first surface and a second surface facing opposite to each other in a thickness direction and including a semiconductor material, the substrate having a main surface facing the same side as the first surface in the thickness direction and positioned between the first surface and the second surface, and a convex portion protruding from the main surface and extending in a main scanning direction; forming a resistor layer including a plurality of heat generating portions arranged in the main scanning direction on the convex portion; forming a wiring layer electrically connected to the plurality of heat generating portions in contact with the resistor layer; wherein the step of forming the main surface and the convex portion includes forming a plurality of groove portions recessed from the first surface, extending in the main scanning direction, and arranged along a sub-scanning direction in the substrate; the plurality of groove portions are interposed between the main surface and the first surface, are spaced apart from each other in the sub-scanning direction, and have a pair of first inclined surfaces inclined with respect to the main surface in a direction away from each other from the main surface toward the first surface; wherein, in the step of forming the plurality of groove portions, a part of the substrate is removed by a blade. Claims 2. The blade has an end surface facing in the radial direction of the blade, and a pair of tapered surfaces connected to the end surface and spaced apart from each other in the rotation axis direction of the blade. The pair of tapered surfaces are inclined with respect to the end surface in a direction away from each other from the end surface toward the rotation axis of the blade. The method of manufacturing a thermal print head according to claim 1, wherein an inclination angle of each of the pair of tapered surfaces with respect to the end surface is 55° or more and 80° or less. Claims 3. The step of forming the main surface and the convex portion includes, after the step of forming the plurality of groove portions, forming a pair of second inclined surfaces interposed between the pair of first inclined surfaces and the first surface and inclined with respect to the main surface in two adjacent groove portions among the plurality of groove portions. The method of manufacturing a thermal print head according to claim 2, wherein the pair of second inclined surfaces are formed by wet etching. Claims 4. The step of forming the main surface and the convex portion includes, before the step of forming the plurality of groove portions, forming a plurality of mask layers extending in the main scanning direction, arranged along the sub-scanning direction, and covering the first surface. In the step of forming the plurality of groove portions, any one of the plurality of groove portions is formed between two adjacent mask layers among the plurality of mask layers, the method of manufacturing a thermal print head according to claim 3.

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