Thermal printhead and method for manufacturing the same

Abstract

To provide a thermal print head capable of preventing a printing medium from being caught by a protrusion.SOLUTION: A thermal print head A1 comprises: a substrate 10 having a main surface 11 and consisting of a single crystal semiconductor; an insulator layer 19; a resistor layer 4 including a plurality of heating parts 41 arrayed in an x-direction; and a heat accumulation layer 15 which is formed between the substrate 10 and the plurality of heating parts 41, and is glaze composed of a glass material. The substrate 10 includes a protrusion 12 which protrudes from the main surface 11 and extends in the x-direction. The protrusion 12 includes: an apex 13 with a top face 131 parallel to the main surface 11; and inclined parts 14 which continue to the apex 13 and to the main surface 11, and are inclined relative to the main surface 11. The inclined parts 14 include: a first inclined surface 141 which continues to the main surface 11, and is inclined relative to the main surface 11 at a first inclination angle α1; and a second inclined surface 142 which is interposed between the first inclined surface 141 and the top face 131, and is inclined relative to the main surface 11 at a second inclination angle α2. The heat accumulation layer 15 is formed only on the top face 131.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a thermal printhead and a method for manufacturing a thermal printhead. [Background technology]

[0002] Patent Document 1 discloses an example of a conventional thermal printhead. Thermal printheads generally have a number of heat-generating elements arranged in the main scanning direction on a head substrate. Each heat-generating element is formed by laminating an upstream conductive layer and a downstream conductive layer on a resistor layer formed on the head substrate via a heat storage layer, exposing a portion of the resistor layer. By passing current between the upstream electrode layer and the downstream electrode layer, the exposed portion (heat-generating element) of the resistor layer generates heat due to Joule heat. The heat storage layer is formed to store the heat generated by the heat-generating elements, enabling high-speed printing.

[0003] The thermal printhead disclosed in Patent Document 1 uses silicon (Si) as the substrate, with convex portions formed by anisotropic etching. A heat storage layer is formed on the top surfaces of the convex portions, and an insulating layer, a resistor layer, an electrode layer, and a protective layer are further formed on the convex portions in this order. The resistor layer exposed from the electrode layer on the convex portions constitutes a heating portion. The printing medium is transported by a platen roller and printed by being pressed against the heating portion arranged on the convex portions. The inclination angle α1 of the inclined outer surface connected to the top surfaces of the convex portions relative to the main surface of the substrate is, for example, 50 to 60 degrees. If the printing medium is thick, the lower end of the leading edge of the printing medium transported by the platen roller may come into contact with the inclined outer surface of the convex portions and become caught. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-11021 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure was conceived in light of the above-mentioned circumstances, and aims to provide a thermal printhead that can prevent the printing medium from getting caught on the convex portions, and to provide a method for manufacturing such a thermal printhead. [Means for solving the problem]

[0006] A thermal printhead provided by a first aspect of the present disclosure includes a substrate having a main surface facing in one direction in the thickness direction and made of a single-crystal semiconductor; a resistor layer formed on the main surface and including a plurality of heat generating elements arranged in a main scanning direction; an insulating layer formed between the substrate and the resistor layer; and a heat storage layer formed between the substrate and the plurality of heat generating elements and being a glaze made of a glass material, wherein the substrate has a convex portion protruding from the main surface and extending in the main scanning direction, the convex portion having a top portion having a top surface parallel to the main surface, and an inclined portion connected to the top portion and the main surface and inclined with respect to the main surface, the inclined portion having a first inclined surface connected to the main surface and inclined with respect to the main surface by a first inclination angle, and a second inclined surface interposed between the first inclined surface and the top surface and inclined with respect to the main surface by a second inclination angle, and the heat storage layer is formed only on the top surface.

[0007] A method for manufacturing a thermal printhead according to a second aspect of the present disclosure includes a preparation step of preparing a substrate made of a single crystal semiconductor; a first etching step of performing a first anisotropic etching on the substrate to form a main surface facing one side in the thickness direction, a convex portion protruding from the main surface, and two grooves recessed from a top surface parallel to the main surface of the convex portion and extending in a main scanning direction; a heat storage layer formation step of arranging a glass paste in an area between the two grooves on the top surface and firing the glass paste; and The method includes a second etching process in which a second anisotropic etching is performed on the base material to remove a portion of the convex portion, thereby forming in the convex portion a top surface which is a region of the top surface sandwiched between the two grooves, a first inclined surface which is connected to the main surface and inclined at a first inclination angle with respect to the main surface, and a second inclined surface which is interposed between the first inclined surface and the top surface and inclined at a second inclination angle with respect to the main surface; and a heat generating portion forming process in which a plurality of heat generating portions arranged in the main scanning direction are formed on the heat storage layer. [Effects of the Invention]

[0008] The thermal printhead according to the present disclosure can prevent the print medium from getting caught on the protrusions.

[0009] 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 explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view showing a thermal printhead according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged plan view of the main part of the thermal printhead shown in FIG. [Figure 3] FIG. 3 is an enlarged plan view of the main part of the thermal printhead shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a cross-sectional view of a main part of the thermal printhead shown in FIG. [Figure 6] FIG. 6 is an enlarged cross-sectional view of a main part of the thermal printhead shown in FIG. [Figure 7] FIG. 7 is a flowchart showing an example of a method for manufacturing the semiconductor device shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 13] FIG. 13 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 14] FIG. 14 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 15] FIG. 15 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 16] FIG. 16 is a cross-sectional view showing a step of another example of a method for manufacturing the thermal printhead shown in FIG. [Figure 17] FIG. 17 is a cross-sectional view showing a step of another example of a method for manufacturing the thermal printhead shown in FIG. [Figure 18] FIG. 18 is an enlarged cross-sectional view of a main part of a thermal printhead according to a second embodiment of the present disclosure. [Figure 19] FIG. 19 is an enlarged cross-sectional view of a main part of a thermal printhead according to a third embodiment of the present disclosure. [Figure 20]FIG. 20 is an enlarged cross-sectional view of a main part of a thermal printhead according to a fourth embodiment of the present disclosure. [Figure 21] FIG. 21 is an enlarged cross-sectional view of a main portion of a thermal printhead according to a fifth embodiment of the present disclosure. [Figure 22] FIG. 22 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. [Figure 23] FIG. 23 is a cross-sectional view showing a step in an example of a method for manufacturing the thermal printhead shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present disclosure will now be described in detail with reference to the drawings.

[0012] In this disclosure, unless otherwise specified, the terms "a certain object A is formed on an object B" and "a certain object A is formed on an object B" include "a certain object A is formed directly on an object B" and "a certain object A is formed on an object B with another object interposed between the objects A and B." Similarly, the terms "a certain object A is disposed on an object B" and "a certain object A is disposed on an object B" include "a certain object A is disposed directly on an object B" and "a certain object A is disposed on an object B with another object interposed between the objects A and B," unless otherwise specified. Similarly, the term "a certain object A is located on an object B" includes "a certain object A is located on an object B in contact with the object B" and "a certain object A is located on an object B with another object interposed between the objects A and B," unless otherwise specified. Additionally, unless otherwise specified, "something A overlaps something B when viewed from a certain direction" includes "something A overlaps the entirety of something B" and "something A overlaps part of something B."

[0013] First Embodiment 1 to 6 show a thermal printhead according to a first embodiment of the present disclosure. The thermal printhead A1 of this embodiment includes a head substrate 1, a connection substrate 5, multiple wires 61 and 62, multiple driver ICs 7, a protective resin 78, and a heat dissipation member 8. The thermal printhead A1 is incorporated into a printer that prints on a print medium (not shown) transported by a platen roller 99 (see FIG. 4). Examples of print media include thermal paper for creating barcode sheets and receipts.

[0014] FIG. 1 is a plan view of a thermal printhead A1. FIG. 2 is an enlarged plan view of a main portion of the thermal printhead A1. FIG. 3 is an enlarged plan view of a main portion of the thermal printhead A1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view of a main portion of the thermal printhead A1, showing an enlarged portion of FIG. 4. FIG. 6 is an enlarged cross-sectional view of a main portion of the thermal printhead A1, showing an enlarged portion of FIG. 5. For ease of understanding, a protective layer 2 (described below) is omitted from FIGS. 1 to 3. For ease of understanding, a protective resin 78 is omitted from FIGS. 1 and 2. For ease of understanding, wires 61 are omitted from FIG. 2. In these figures, the longitudinal direction (main scanning direction) of the head substrate 1 is defined as the x-direction, the lateral direction (sub-scanning direction) as the y-direction, and the thickness direction as the z-direction. In addition, with regard to the y direction, the lower side in Figures 1 to 3 (the right side in Figures 4 to 6) is the "upstream" side where the print medium is fed, and the upper side in Figures 1 to 3 (the left side in Figures 4 to 6) is the "downstream" side where the print medium is discharged. In addition, with regard to the z direction, the upper side in Figures 4 to 6 (the direction indicated by the arrow indicating the z direction) is the "upper" side, and the opposite direction is the "lower" side. This also applies to the following figures.

[0015] 4, in the thermal printhead A1, the head substrate 1 and the connection substrate 5 are mounted adjacent to each other in the y direction on the heat dissipation member 8. The head substrate 1 has a plurality of heat generating elements 41 arranged in the x direction, as will be described in detail later. These heat generating elements 41 are selectively driven to generate heat by a driver IC 7 mounted on the connection substrate 5, and print on a print medium pressed against the heat generating elements 41 by a platen roller 99 in accordance with a print signal transmitted from the outside via a connector 59.

[0016] As shown in FIGS. 1 to 6, the head substrate 1 includes a base material 10, a heat storage layer 15, an insulating layer 19, a protective layer 2, an electrode layer 3, and a resistor layer 4.

[0017] The substrate 10 is made of a single-crystal semiconductor. Si is a suitable single-crystal semiconductor. As shown in FIG. 1, the substrate 10 has an elongated rectangular shape with the x direction as the longitudinal direction and the y direction as the transverse direction when viewed in the z direction. The size of the substrate 10 is not limited, but as an example, the dimension in the x direction is, for example, 20 mm to 300 mm, the dimension in the y direction is, for example, 1.0 mm to 5.0 mm, and the dimension in the z direction is, for example, 725 μm. In the substrate 10, the side closer to the driver IC 7 in the y direction is the upstream side, and the side farther from the driver IC 7 is the downstream side. The printing medium is transported from the upstream side to the downstream side in the y direction by a platen roller 99.

[0018] As shown in FIGS. 1, 2, 5, and 6, the substrate 10 has a main surface 11 and protrusions 12. The main surface 11 faces upward in the z direction. In the present disclosure, the main surface 11 extends along the xy plane (a plane defined by the x and y directions; the same applies to other planes) and is a plane substantially parallel to the xy plane. The main surface 11 is a (100) plane. The protrusions 12 protrude from the main surface 11 in the z direction and extend in the x direction. The protrusions 12 are formed near the downstream side of the main surface 11. The cross-sectional shape of the protrusions 12 along the yz plane is uniform in the x direction. Hereinafter, the cross-section along the yz plane will be referred to as the "yz cross-section." The protrusions 12 have a y-direction dimension W1 at a lower end in the z direction of about 500 μm, for example, and a y-direction dimension W2 at an upper end in the z direction of about 200 μm, for example. Although dimensions W1 and W2 are not limited, in this embodiment, dimension W1 is between two and ten times dimension W2. Furthermore, dimension H1 in the z direction of protrusion 12 is, for example, approximately 150 μm. As shown in FIG. 6 , protrusion 12 includes a peak 13 and a pair of inclined portions 14.

[0019] As shown in FIGS. 5 and 6, the apex 13 is a portion of the protrusion 12 that is relatively far from the main surface 11 in the z direction. The apex 13 has a top surface 131 that is parallel to the main surface 11. The top surface 131 is substantially flat. When viewed in the z direction, the top surface 131 has an elongated rectangular shape that extends long in the x direction. The dimension H1 is the distance between the top surface 131 and the main surface 11 in the z direction.

[0020] As shown in FIGS. 5 and 6 , the pair of inclined portions 14 are portions of the convex portion 12 that are inclined with respect to the main surface 11 and the top surface 131 so that the position decreases with increasing distance from the apex 13 in the y direction. Each of the pair of inclined portions 14 is connected to the main surface 11 and the apex 13 and is sandwiched between them in the y direction. The pair of inclined portions 14 includes an inclined portion 14 on the upstream side and an inclined portion 14 on the downstream side with respect to the apex 13. As shown in FIG. 6 , each of the pair of inclined portions 14 has a first inclined surface 141, a second inclined surface 142, and a third inclined surface 143. The first inclined surface 141, the second inclined surface 142, and the third inclined surface 143 are aligned in the y direction. The first inclined surface 141, the second inclined surface 142, and the third inclined surface 143 are all inclined with respect to the main surface 11 and the top surface 131.

[0021] The first inclined surface 141 is connected to the main surface 11 and the second inclined surface 142 in the y direction and is inclined at a first inclination angle α1 with respect to the main surface 11. In this embodiment, the first inclined surface 141 is a (111) plane, and the first inclination angle α1 is, for example, 54.8°. The second inclined surface 142 is connected to the first inclined surface 141 and the third inclined surface 143 in the y direction and is inclined at a second inclination angle α2 with respect to the main surface 11. The second inclination angle α2 is smaller than the first inclination angle α1 and, in this embodiment, is, for example, 31°. The third inclined surface 143 is connected to the second inclined surface 142 and the top surface 131 in the y direction and is inclined at a third inclination angle α3 with respect to the main surface 11. The third inclination angle α3 is larger than the second inclination angle α2. In this embodiment, the third inclined surface 143 is a (111) plane, and the third inclined angle α3 is the same as the first inclined angle α1, for example, 54.8°. The dimension of the third inclined surface 143 in a direction perpendicular to the x-direction is sufficiently smaller than those of the first inclined surface 141 and the second inclined surface 142. The first inclined angle α1, the second inclined angle α2, and the third inclined angle α3 are not limited. It is sufficient that the second inclined angle α2 is smaller than the first inclined angle α1, and the third inclined angle α3 is larger than the second inclined angle α2.

[0022] The heat storage layer 15 is a glaze made of a glass material such as amorphous glass. The glaze (heat storage layer 15) is formed by firing a glass paste, for example. In this embodiment, the thermal expansion coefficient of the heat storage layer 15 is approximately the same as that of Si, which is the material of the base material 10. The characteristics of the glass material of the heat storage layer 15 are not limited. As shown in FIGS. 5 and 6, the heat storage layer 15 is disposed on the top 13 of the protrusion 12. The heat storage layer 15 is in contact with the top surface 131, and in this embodiment, the heat storage layer 15 is not in contact with the first inclined surface 141, the second inclined surface 142, or the third inclined surface 143. The heat storage layer 15 is formed only on the top surface 131. The heat storage layer 15 extends in the x direction and is formed across the entire width of the top surface 131 in the y direction.

[0023] In this embodiment, as shown in the manufacturing method described later, the heat storage layer 15 is formed by a process of applying glass paste using a dispenser and firing the applied paste. The number of times the glass paste is applied is not limited, and the glass paste may be applied and fired only once, or may be applied two or more times. The method of applying the glass paste is also not limited, and the glass paste may be applied by stencil printing (e.g., screen printing), for example.

[0024] In this embodiment, the thickness dimension (dimension in the z direction) H2 of the heat storage layer 15 is, for example, 10 μm or more and 200 μm or less (preferably 15 μm or more and 60 μm or less). The ratio of the thickness dimension H2 to the width dimension (dimension in the y direction) of the heat storage layer 15 (so-called aspect ratio) is 0.05 or more and 0.25 or less. In this embodiment, the heat storage layer 15 is formed over the entire width of the top surface 131 in the y direction, so the width dimension of the heat storage layer 15 is the same as the width dimension (dimension in the y direction) of the top surface 131, i.e., the y-direction dimension W2 of the end portion on the upper side in the z direction of the protrusion 12. Note that the dimensions of the heat storage layer 15 are not limited. The thickness dimension H2 and width dimension W2 of the heat storage layer 15 are designed so that the heat storage layer 15 can store sufficient heat but does not store too much heat unnecessarily. The number of times and the method of applying the glass paste are determined depending on the required thickness (or aspect ratio) of the heat storage layer 15.

[0025] As shown in FIG. 6, a pair of rounded portions 151 is formed on the upper surface of the heat storage layer 15 at both ends in the y direction. Each of the pair of rounded portions 151 is a curved portion that rises up. The pair of rounded portions 151 makes the surface of the heat storage layer 15 smoothly continue to each of the third inclined surfaces 143 of the pair of inclined portions 14 (convex portions 12). Each rounded portion 151 is formed by firing a glass paste when forming the heat storage layer 15. In the example shown in FIG. 6, the upper surface of the heat storage layer 15 has a shape in which a substantially flat surface is interposed between the pair of rounded portions 151 in the y direction. Note that the upper surface of the heat storage layer 15 may not have this substantially flat surface, and the pair of rounded portions 151 may be connected to each other. In this case, the upper surface of the heat storage layer 15 has a convex surface that curves upward in the z direction.

[0026] As shown in FIGS. 5 and 6 , the insulating layer 19 is formed on the main surface 11 of the substrate 10 and covers the substrate 10 and the heat storage layer 15. The insulating layer 19 contacts the main surface 11, each pair of the first inclined surface 141, the second inclined surface 142, and the third inclined surface 143 of the protrusion 12, and the upper surface of the heat storage layer 15. The insulating layer 19 is intended to more reliably insulate the substrate 10 from the resistor layer 4 and the electrode layer 3. The insulating layer 19 may be formed in the region of the substrate 10 where the resistor layer 4 or the electrode layer 3 is to be formed. The insulating layer 19 is made of an insulating material, such as SiO or SiN (silicon nitride). The insulating layer 19 made of SiO can be formed, for example, by deposition using TEOS (tetraethyl orthosilicate; also known as tetraethoxysilane) as a source gas. The thickness of the insulating layer 19 is not particularly limited and is, for example, 1 μm to 10 μm.

[0027] As shown in FIGS. 5 and 6, the resistor layer 4 is formed on the insulating layer 19 and covers the insulating layer 19. The resistor layer 4 is formed across the main surface 11 and the protrusions 12, with the insulating layer 19 sandwiched between them. The resistor layer 4 is made of, for example, TaN (tantalum nitride). There are no particular limitations on the thickness of the resistor layer 4, and it is, for example, 0.02 μm or more and 0.1 μm or less (preferably about 0.08 μm).

[0028] As shown in FIGS. 3, 5, and 6, the resistor layer 4 includes a plurality of heat generating portions 41. The heat generating portions 41 are exposed portions of the resistor layer 4 that are not covered by the electrode layer 3 described below. The heat generating portions 41 are selectively energized to locally heat the print medium. The heat generating portions 41 are arranged in the x direction and spaced apart from one another in the x direction. The formation area of ​​the heat generating portions 41 in the y direction is an area that includes part or all of the apex 13 (top surface 131) of the protrusion 12 in the y direction. Therefore, each heat generating portion 41 overlaps the heat storage layer 15 when viewed in the z direction.

[0029] The electrode layer 3 forms a conductive path for supplying electricity to the plurality of heat generating elements 41. The electrode layer 3 is laminated on the resistor layer 4 and supported by the substrate 10. The electrode layer 3 is made of a metal material having a lower resistance value than the resistor layer 4, such as Cu (copper). The thickness of the electrode layer 3 is not particularly limited and is, for example, 0.3 μm or more and 2.0 μm or less. The electrode layer 3 may also be configured by laminating a Cu layer and a Ti (titanium) layer. In this case, the Ti layer is interposed between the Cu layer and the resistor layer 4 and has a thickness of, for example, about 150 nm.

[0030] 1 to 3, 5 and 6, the electrode layer 3 includes a plurality of individual electrodes 31 and a common electrode 32. Portions of the resistor layer 4 that are exposed from the electrode layer 3 between the plurality of individual electrodes 31 and the common electrode 32 form a plurality of heat generating portions 41.

[0031] Each of the multiple individual electrodes 31 has a strip shape extending generally in the y direction. Each individual electrode 31 is disposed upstream of each heat generating portion 41 in the y direction. As shown in FIGS. 3 and 6, in this embodiment, the downstream end of each individual electrode 31 in the y direction extends to the inclined portion 14 on the upstream side in the y direction. An electrode pad portion 311 is formed on the upstream end of each individual electrode 31 in the y direction. The electrode pad portion 311 is connected to the driver IC 7 mounted on the connection board 5 by a wire 61.

[0032] As shown in FIGS. 2 and 3 , the common electrode 32 includes a common portion 323 and multiple comb-tooth portions 324. The common portion 323 connects the multiple comb-tooth portions 324 together. The common portion 323 extends in the x direction. The common portion 323 is located downstream of the multiple comb-tooth portions 324 in the y direction. Each comb-tooth portion 324 is strip-shaped and extends in the y direction from the upstream edge of the common portion 323. The multiple comb-tooth portions 324 are spaced apart from each other and aligned in the x direction. The upstream tip of each comb-tooth portion 324 in the y direction faces the tip of each individual electrode 31 at a predetermined interval. Therefore, the resistor layer 4 is exposed from the electrode layer 3 between the upstream tip of each comb-tooth portion 324 in the y direction and the downstream tip of each individual electrode 31 in the y direction. 3 and 6, the tip of each comb tooth portion 324 on the upstream side in the y direction extends to the inclined portion 14 on the downstream side in the y direction. The downstream portion of each comb tooth portion 324 in the y direction and the common portion 323 are formed on the main surface 11, as shown in FIG.

[0033] The shapes of the individual electrodes 31 and the common electrode 32 as viewed in the z direction, and the formation areas of the individual electrodes 31 and the common electrode 32 are not limited to those described above. For example, the common electrode 32 may also be arranged upstream of the heat generating portions 41 in the y direction. In this case, the common portion 323 is arranged upstream of the multiple comb tooth portions 324 in the y direction, and the multiple comb tooth portions 324 are each arranged between the individual electrodes 31. Then, folded wiring for electrically connecting the comb tooth portions 324 and the individual electrodes 31 is arranged downstream of the heat generating portions 41 in the y direction.

[0034] 5 and 6, the protective layer 2 covers the electrode layer 3 and the resistor layer 4. The protective layer 2 is made of an insulating material, such as SiO2, SiN, SiC (silicon carbide), AlN (aluminum nitride), or a laminate of two or more of these. The thickness of the protective layer 2 is not particularly limited, and is, for example, 1.0 μm or more and 10 μm or less.

[0035] 5, the protective layer 2 has pad openings 21 penetrating in the z direction. The pad openings 21 expose the electrode pad portions 311 provided on the individual electrodes 31, respectively.

[0036] As shown in FIGS. 1 and 4, the connection board 5 is disposed adjacent to the head substrate 1 on the upstream side in the y direction. The connection board 5 is, for example, a PCB board. As shown in FIG. 1, the connection board 5 has, for example, an elongated rectangular shape with the x direction as the longitudinal direction when viewed in the z direction. As shown in FIG. 4, the connection board 5 has a driver IC 7 and a connector 59 mounted thereon.

[0037] The connector 59 is used to connect the thermal printhead A1 to a printer (not shown). The connector 59 is attached to the connection board 5 and connected to the wiring pattern (not shown) of the connection board 5, as shown in FIG.

[0038] As shown in FIGS. 1 and 4, the driver IC 7 is mounted on the connection board 5 and individually energizes the plurality of heat generating elements 41. As shown in FIGS. 4 and 5, the driver IC 7 is connected to each electrode pad portion 311 of each individual electrode 31 by a plurality of wires 61. The driver IC 7 is also connected to a wiring pattern formed on the connection board 5 by a plurality of wires 62. A print signal, a control signal, and a voltage supplied to the plurality of heat generating elements 41 transmitted from the outside are input to the driver IC 7 via a connector 59. The plurality of heat generating elements 41 are individually energized in accordance with the print signal and control signal, thereby selectively generating heat.

[0039] 4 and 5, the driver IC 7 and the plurality of wires 61, 62 are covered with a protective resin 78 formed so as to straddle the head substrate 1 and the connection substrate 5. The protective resin 78 is made of a black insulating material such as epoxy resin.

[0040] 4, the heat dissipation member 8 supports the head substrate 1 and the connection substrate 5, and is provided to dissipate to the outside some of the heat generated by the multiple heat generating portions 41. The heat dissipation member 8 is made of a metal such as aluminum.

[0041] Next, an example of a method for manufacturing a thermal printhead A1 will be described below with reference to Figures 7 to 15. Figure 7 is a flowchart showing an example of a method for manufacturing a thermal printhead A1. Figures 8 to 15 are cross-sectional views showing one step of an example of a method for manufacturing a thermal printhead A1, and correspond to the cross section shown in Figure 6. The x, y, and z directions shown in Figures 8 to 15 are the same as those in Figures 1 to 6.

[0042] As shown in FIG. 7, the manufacturing method of the thermal printhead A1 includes a substrate preparation process S10, a first etching process S20, a heat storage layer formation process S30, a second etching process S40, a re-firing process S50, an insulating layer formation process S60, a heat generating portion formation process S70, a protective layer formation process S80, and a cutting process S90.

[0043] The substrate preparation step S10 is a step of preparing a substrate 10A, which will be the material. In this step, the substrate 10A is prepared as shown in FIG. 8. The substrate 10A is made of a single-crystal semiconductor, such as a Si wafer. The substrate 10A has a main surface 11A. The main surface 11A is substantially flat and faces upward in the z direction. The main surface 11A is a (100) plane.

[0044] The first etching step S20 is a step of performing a first etching process on the substrate 10A, which is a step of forming the protrusions 12A as shown in FIG. 9. In this step, a predetermined mask layer 91 (indicated by two-dot chain lines in FIGS. 8 and 9) is first formed on a portion of the main surface 11A of the substrate 10A. The mask layer 91 extends in the x direction and has two slits 92. The two slits 92 extend parallel to each other in the x direction and penetrate the mask layer 91 in the z direction. Then, anisotropic etching is performed using, for example, an alkaline aqueous solution. Examples of this alkaline aqueous solution include KOH (potassium hydroxide) and TMAH (tetramethylammonium hydroxide). As a result, the substrate 10 having the main surface 11 and the protrusions 12A is formed as shown in FIG. The main surface 11 is a (100) plane, just like the main surface 11A.

[0045] The protrusion 12A protrudes from the main surface 11 in the z direction and extends in the x direction. The protrusion 12A includes an apex 13A and a pair of inclined portions 14A. The apex 13A has a top surface 131A parallel to the main surface 11. When viewed in the z direction, the top surface 131A has an elongated rectangular shape extending long in the x direction. The top surface 131A is a (100) plane. The top surface 131A is a part of the main surface 11A that is covered by the mask layer 91 and remains unetched. The apex 13A also has two grooves 132A at positions corresponding to the two slits 92 in the mask layer 91. Each groove 132A is recessed from the top surface 131A in the z direction, extends in the x direction, and is V-shaped when viewed in the x direction. A pair of side surfaces constituting each groove 132A are each a (111) plane and are inclined with respect to the main surface 11 and the top surface 131A. The third inclination angle α3 of each side surface is, for example, 54.8 degrees. The pair of inclined portions 14A are arranged on either side of the top portion 13A in the y direction. Each of the pair of inclined portions 14A has an inclined surface 141A. Each of the pair of inclined surfaces 141A is a (111) plane and is inclined with respect to the main surface 11 and the top surface 131A. The first inclination angle α1 of each inclined surface 141A is, for example, 54.8 degrees. Thereafter, the mask layer 91 is removed.

[0046] The heat storage layer forming step S30 is a step of forming the heat storage layer 15, as shown in FIG. 10 . In this step, first, glass paste is applied to the region between the two grooves 132A on the top surface 131A of the convex portion 12A. In this embodiment, the glass paste is applied using, for example, a dispenser. The applied glass paste has fluidity, but surface tension prevents it from crossing the boundary line between the top surface 131A and the groove 132A. In this embodiment, the third inclination angle α3 of the side surface of the groove 132A is relatively large, which enhances this effect. In this embodiment, after applying the glass paste, another glass paste is applied on top of it. That is, in this embodiment, the glass paste is applied twice. Note that the number of times the glass paste is applied is not limited. When applying the glass paste twice or more, the applied glass paste may be dried in a drying process to make it easier to maintain its shape before applying the next glass paste. The method of applying the glass paste is not limited, and the glass paste may be applied by, for example, stencil printing (e.g., screen printing).

[0047] The glass paste is then fired to form the heat storage layer 15 as shown in FIG. 10. The heat generated during firing causes the glass paste to become fluid, but surface tension prevents it from crossing the boundary line between the top surface 131A and the groove 132A. In this embodiment, the third inclination angle α3 of the side surface of the groove 132A is relatively large, which enhances this effect. The glass paste is adjusted so that the thermal expansion coefficient of the fired heat storage layer 15 is approximately the same as that of Si, the material of the substrate 10. The composition of the glass paste is not limited. Even when glass paste is applied multiple times, by using glass paste of the same composition, the fired heat storage layer 15 will be integrated and have no boundaries. When glass paste is applied multiple times, firing may be performed each time a glass paste is applied.

[0048] The second etching step S40 is a second etching process, which removes a portion of the protrusion 12A as shown in FIG. 11. In this process, a second anisotropic etching is performed again using an alkaline aqueous solution. The alkaline aqueous solution used is KOH or TMAH. In the second etching step S40, the heat storage layer 15 functions as a mask layer, so there is no need to form a separate mask layer. The second anisotropic etching removes the portions of the inclined portions 14A and the top portion 13A indicated by the two-dot chain lines, as shown in FIG. 11. This forms the second inclined surface 142. The second inclination angle α2 of the second inclined surface 142 is, for example, 31°. The portion of the inclined surface 141A that is not removed by etching becomes the first inclined surface 141. Furthermore, the region of the top surface 131A between the two grooves 132A remains and becomes the top surface 131. Furthermore, one side surface of each groove 132A (the side surface closer to the heat storage layer 15) remains and connects to the top surface 131, forming a third inclined surface 143 that is inclined with respect to the main surface 11 by a third inclination angle α3.

[0049] The re-firing step S50 is a step of re-firing the thermal storage layer 15. In the second etching step S40, fine irregularities may be formed on the surface of the thermal storage layer 15. In the re-firing step S50, the thermal storage layer 15 is melted and then re-firing is performed to solidify it. This makes the surface of the thermal storage layer 15 a smooth surface. Note that the re-firing step S50 may be omitted.

[0050] The insulating layer forming step S60 is a step of forming an insulating layer 19 that covers the heat storage layer 15 and the base material 10, as shown in Fig. 12. In this step, a film is formed using, for example, CVD, with TEOS as a raw material gas. The insulating layer 19 covers the main surface 11, the pair of inclined portions 14 (first inclined surface 141, second inclined surface 142, third inclined surface 143) of the protrusion 12, and the heat storage layer 15. The method of forming the insulating layer 19 is not limited.

[0051] The heating element forming step S70 is a step of forming the heating elements 41 and the electrode layer 3 for supplying current to the heating elements 41 on the insulating layer 19. First, as shown in FIG. 13, a resistor film 4A is formed (S71). The resistor film 4A is formed by, for example, forming a TaN thin film on the insulating layer 19 by sputtering. The resistor film 4A covers the entire surface of the insulating layer 19. Next, as shown in FIG. 14, a conductive film 3A is formed (S72). The conductive film 3A is formed by, for example, forming a layer made of Cu by plating or sputtering. The conductive film 3A covers the entire surface of the resistor film 4A. Note that the conductive film 3A may be formed by forming a Ti layer on the insulating layer 19 and then forming a Cu layer. Next, as shown in FIG. 15, the conductive film 3A and the resistor film 4A are selectively etched to partially remove the conductive film 3A and the resistor film 4A (S73). As a result, the resistor layer 4 separated in the x direction, and the plurality of individual electrodes 31 and the common electrode 32 covering the resistor layer 4 except for the plurality of heat generating portions 41 are formed.

[0052] The protective layer forming step S80 is a step of forming the protective layer 2. This step is performed by depositing, for example, SiN on each of the insulating layer 19, the electrode layer 3, and the resistor layer 4, using, for example, CVD. Thereafter, to form the pad opening 21, the protective layer 2 is partially removed by etching or the like.

[0053] The cutting step S90 is a step of cutting the substrate 10. In this step, the substrate 10 is cut along the x and y directions to separate it into individual pieces. In this way, the head substrate 1 is obtained. Then, the thermal printhead A1 shown in FIGS. 1 to 6 is manufactured by assembling the head substrate 1 and the connection board 5 onto the heat dissipation member 8, mounting the driver IC 7 on the connection board 5, bonding the multiple wires 61 and 62, forming the protective resin 78, and so on.

[0054] The above-described manufacturing method is an example and is not limited to this. For example, the second etching step S40 may be performed before the heat storage layer forming step S30. Hereinafter, the above-described manufacturing method will be referred to as the "first manufacturing method," and the manufacturing method in which the second etching step S40 is performed before the heat storage layer forming step S30 will be referred to as the "second manufacturing method." The second manufacturing method is a manufacturing method in which the heat storage layer forming step S30 and the second etching step S40 are interchanged in the first manufacturing method. The substrate preparation step S10 and the first etching step S20 are common to the first manufacturing method.

[0055] In the second manufacturing method, a second etching step S40 is performed after the first etching step S20. In the second etching step S40, before performing the etching process, a mask layer 93 is formed to cover the area between the two grooves 132A on the top surface 131A of the convex portion 12A, as shown in FIG. 16. Thereafter, a second anisotropic etching is performed, and the portions of each inclined portion 14A and the top portion 13A indicated by the two-dot chain lines are removed, as shown in FIG. 17. This forms a first inclined surface 141, a second inclined surface 142, and a third inclined surface 143. Furthermore, the area of ​​the top surface 131A covered by the mask layer 93 remains as the top surface 131. Then, the mask layer 93 is removed. Next, in a heat storage layer forming step S30, a glass paste is applied to the top surface 131 and fired to form the heat storage layer 15. Although the applied glass paste and the glass paste heated during firing are fluid, surface tension prevents them from crossing the boundary line between the top surface 131A and the third inclined surface 143. In the second manufacturing method, the second etching step S40 is performed before the heat storage layer 15 is formed, so the re-firing step S50 can be omitted. The subsequent insulating layer forming step S60, heat generating portion forming step S70, protective layer forming step S80, and cutting step S90 are the same as in the first manufacturing method.

[0056] Next, the operation of the thermal printhead A1 will be described.

[0057] According to this embodiment, the thermal printhead A1 has an inclined portion 14 that includes a first inclined surface 141 and a second inclined surface 142. The second inclined surface 142 is disposed between the first inclined surface 141 and the top surface 131 in the y direction. The second inclination angle α2 of the second inclined surface 142 is smaller than the first inclination angle α1 of the first inclined surface 141. Therefore, compared to when the inclined portion 14 does not include the second inclined surface 142, the print medium transported by the platen roller 99 is less likely to get caught on the protrusions 12. The inclined portion 14 also includes a third inclined surface 143 that is disposed between the second inclined surface 142 and the top surface 131 in the y direction. However, the dimension of the third inclined surface 143 in the direction perpendicular to the x direction is sufficiently small that it has little effect on the print medium getting caught on the protrusions 12.

[0058] Furthermore, according to the present embodiment, third inclination angle α3 of third inclined surface 143 connected to top surface 131 in the y direction is larger than second inclination angle α2 of second inclined surface 142. Therefore, compared to the case where second inclined surface 142 is connected to top surface 131, it is possible to further prevent the glass paste placed on top surface 131 from flowing out from top surface 131 when the glass paste is placed in the manufacturing process and when it is heated during firing.

[0059] Furthermore, according to this embodiment, the thermal printhead A1 includes a heat storage layer 15 formed between the substrate 10 and the resistor layer 4. When viewed in the z direction, each heat generating portion 41 of the resistor layer 4 overlaps the heat storage layer 15. Therefore, heat generated by each heat generating portion 41 is stored in the heat storage layer 15. The heat storage layer 15 is formed by depositing and firing a glass paste. Therefore, compared to, for example, forming a heat storage layer by sputtering SiO2, the heat storage layer 15 can be formed with an overwhelmingly greater thickness in an overwhelmingly shorter time. This contributes greatly to improving the manufacturing efficiency and reducing costs of the thermal printhead A1.

[0060] Furthermore, according to this embodiment, the heat storage layer 15 is formed by applying the glass paste twice, which makes it possible to form a thicker heat storage layer 15 compared to applying the glass paste only once.

[0061] Furthermore, according to this embodiment, the ratio of the dimension H2 in the z direction to the width (dimension W2 in the y direction) of the heat storage layer 15 is 0.05 or more and 0.2 or less. Therefore, the heat storage layer 15 can appropriately store the heat generated by each heat generating portion 41.

[0062] Furthermore, in this embodiment, the substrate 10 has protrusions 12, and the plurality of heat generating portions 41 are formed on the tops 13 (top surfaces 131) of the protrusions 12. This ensures that the print medium is pressed against the heat generating portions 41 via the platen roller 99. Furthermore, because the protrusions 12 are formed by anisotropic etching of a single crystal semiconductor, their yz cross sections are uniform in the x direction. In other words, the pressing contact state of the print medium against the heat generating portions 41 is consistent at each point in the x direction. This does not change even if the production lot of the head substrate 1 is different, and therefore variations in print quality can be suppressed.

[0063] 18 to 23 show other embodiments of the present disclosure. In these figures, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as those in the above embodiment.

[0064] Second Embodiment 18 is an enlarged cross-sectional view of a thermal printhead A2 according to a second embodiment of the present disclosure, corresponding to FIG. 6. The thermal printhead A2 of this embodiment differs from the above-described embodiment in that a parallel surface 144 is formed between a second inclined surface 142 and a third inclined surface 143. The configuration and operation of other parts of this embodiment are the same as those of the first embodiment. Note that the parts of the first embodiment described above may be combined in any desired manner.

[0065] Each inclined portion 14 of the substrate 10 according to this embodiment further includes a parallel surface 144. The parallel surface 144 is disposed between the second inclined surface 142 and the third inclined surface 143 in the y direction and is connected to the second inclined surface 142 and the third inclined surface 143. The parallel surface 144 is parallel to the main surface 11.

[0066] In this embodiment as well, the inclined portion 14 includes a second inclined surface 142 disposed between the first inclined surface 141 and the top surface 131, thereby preventing the print medium from getting caught on the protrusions 12. Furthermore, the inclined portion 14 includes a third inclined surface 143 that connects to the top surface 131 in the y direction, thereby further preventing the glass paste from flowing out from the top surface 131 during the manufacturing process. Furthermore, the thermal printhead A2 has a configuration in common with the thermal printhead A1, and therefore achieves the same effects as the thermal printhead A1.

[0067] Third Embodiment 19 is an enlarged cross-sectional view of a thermal printhead A3 according to a third embodiment of the present disclosure, corresponding to FIG. 6. The thermal printhead A3 of this embodiment differs from the above-described embodiments in that a fourth inclined surface 145 is formed between the second inclined surface 142 and the third inclined surface 143. The configuration and operation of other parts of this embodiment are the same as those of the first embodiment. Note that the parts of the first and second embodiments may be combined in any desired manner.

[0068] Each inclined portion 14 of the substrate 10 according to this embodiment further includes a fourth inclined surface 145. The fourth inclined surface 145 is disposed between the second inclined surface 142 and the third inclined surface 143 in the y direction and is connected to the second inclined surface 142 and the third inclined surface 143. The fourth inclined surface 145 is inclined at a third inclination angle α3 with respect to the main surface 11 and is inclined in the opposite direction to the third inclined surface 143 in the y direction. In other words, the third inclined surface 143 and the fourth inclined surface 145 form a V-shape when viewed in the x direction. The fourth inclined surface 145 is a portion of the other side surface (the side surface away from the heat storage layer 15) of the groove 132A shown in FIG. 10 that remains without being removed in the second etching step S40.

[0069] In this embodiment as well, the inclined portion 14 includes a second inclined surface 142 disposed between the first inclined surface 141 and the top surface 131, thereby preventing the print medium from getting caught on the protrusions 12. Furthermore, the inclined portion 14 includes a third inclined surface 143 that connects to the top surface 131 in the y direction, thereby further preventing the glass paste from flowing out from the top surface 131 during the manufacturing process. Furthermore, the thermal printhead A3 has a configuration in common with the thermal printhead A1, and therefore achieves the same effects as the thermal printhead A1.

[0070] The first to third embodiments differ from one another in the shape of the protrusions 12. These differences arise from the positions in the y direction and the depths (dimensions in the z direction) of the pair of grooves 132A formed in the first etching step S20, the etching processing time in the second etching step S40, etc. Conversely, by adjusting these parameters, the shape of the protrusions 12 can be adjusted to a desired shape.

[0071] <Fourth embodiment> 20 is an enlarged cross-sectional view of a main portion of a thermal printhead A4 according to a fourth embodiment of the present disclosure, and corresponds to FIG. 6. The thermal printhead A4 of this embodiment differs from the above-described embodiments in that the insulating layer 19 does not cover the heat storage layer 15. The configuration and operation of other parts of this embodiment are the same as those of the first embodiment. Note that the parts of the first to third embodiments may be combined in any desired manner.

[0072] The insulating layer 19 according to this embodiment covers only the main surface 11 and the pair of inclined portions 14 (first inclined surface 141, second inclined surface 142, third inclined surface 143) of the protrusion 12, and does not cover the heat storage layer 15. Such an insulating layer 19 is formed in the insulating layer forming step S60 by, for example, thermal oxidation treatment in which the base material 10 is thermally oxidized to form an SiO2 film, rather than by laminating SiO2 using CVD. In this embodiment, although the insulating layer 19 does not cover the heat storage layer 15, the heat storage layer 15 itself is an insulator, and therefore the base material 10 can be insulated from the resistor layer 4 and the electrode layer 3.

[0073] In this embodiment as well, the inclined portion 14 includes a second inclined surface 142 disposed between the first inclined surface 141 and the top surface 131, thereby preventing the print medium from getting caught on the protrusions 12. Furthermore, the inclined portion 14 includes a third inclined surface 143 that connects to the top surface 131 in the y direction, thereby further preventing the glass paste from flowing out from the top surface 131 during the manufacturing process. Furthermore, the thermal printhead A4 has a configuration in common with the thermal printhead A1, and therefore achieves the same effects as the thermal printhead A1.

[0074] Furthermore, in this embodiment, the insulating layer 19 can be formed of an SiO2 film obtained by thermally oxidizing the substrate 10. Therefore, the manufacturing process can be simplified compared to when SiO2 is deposited using CVD in the insulating layer forming step S60. Note that when the thermal printhead A4 is manufactured by the second manufacturing method, the insulating layer 19 may be formed between the heat storage layer 15 and the top surface 131.

[0075] Fifth Embodiment 21 to 23 are diagrams illustrating a thermal printhead A5 according to a fifth embodiment of the present disclosure. FIG. 21 is an enlarged cross-sectional view of a main portion of the thermal printhead A5, corresponding to FIG. 6. FIGS. 22 and 23 are cross-sectional views showing a step in an exemplary method for manufacturing the thermal printhead A5, corresponding to the cross section shown in FIG. 21. The thermal printhead A5 of this embodiment differs from the above-described embodiments in that the third inclined surface 143 is a surface that is substantially perpendicular to the main surface 11. The configuration and operation of other parts of this embodiment are similar to those of the first embodiment. Note that the parts of the first to fourth embodiments may be combined in any desired manner.

[0076] 21, in the protrusion 12 of the substrate 10 according to this embodiment, the third inclined surface 143 is a surface that is approximately perpendicular to the main surface 11. In other words, the third inclination angle α3 is approximately a right angle. The method for manufacturing the thermal printhead A5 differs from the method for manufacturing the thermal printhead A1 in the method for forming the grooves 132A.

[0077] In the method for manufacturing thermal printhead A5, as shown in FIG. 22, the mask layer 91 formed on the main surface 11A in the first etching step S20 does not include slits 92. Therefore, grooves 132A are not formed in the first etching step S20. Thereafter, as shown in FIG. 23, two grooves 132A are formed in the top surface 131A. The method for forming the grooves 132A is not limited; for example, they may be formed using a laser or may be formed by using a dicing blade to create a so-called half-cut state. The subsequent steps are the same as those in the method for manufacturing thermal printhead A1.

[0078] In this embodiment as well, the inclined portion 14 includes a second inclined surface 142 disposed between the first inclined surface 141 and the top surface 131, thereby preventing the print medium from getting caught on the protrusions 12. Furthermore, the inclined portion 14 includes a third inclined surface 143 that connects to the top surface 131 in the y direction, thereby further preventing the glass paste from flowing out from the top surface 131 during the manufacturing process. Furthermore, the thermal printhead A5 has a configuration in common with the thermal printhead A1, and therefore achieves the same effects as the thermal printhead A1.

[0079] The thermal printhead and the method for manufacturing a thermal printhead according to the present disclosure are not limited to the above-described embodiment, and the specific configuration of each part of the thermal printhead according to the present disclosure and the specific processing of each step of the method for manufacturing a thermal printhead according to the present disclosure can be freely designed and modified in various ways.

[0080] [Appendix 1] a substrate (10) having a main surface (11) facing one side in the thickness direction (z direction) and made of a single crystal semiconductor; a resistor layer (4) formed on the main surface and including a plurality of heat generating portions (41) arranged in the main scanning direction (x direction); an insulating layer (19) formed between the substrate and the resistor layer; a heat storage layer (15) formed between the base material and the plurality of heat generating portions and being a glaze made of a glass material; Equipped with the base material has a protrusion (12) protruding from the main surface and extending in the main scanning direction; The convex portion is a top portion (13) having a top surface (131) parallel to the main surface; an inclined portion (14) connected to the top portion and the main surface and inclined relative to the main surface; Equipped with The inclined portion is a first inclined surface (141) connected to the main surface and inclined at a first inclination angle with respect to the main surface; a second inclined surface (142) interposed between the first inclined surface and the top surface and inclined at a second inclination angle with respect to the main surface; Equipped with The heat storage layer is formed only on the top surface. Thermal print head. [Appendix 2] The first tilt angle is greater than the second tilt angle. 10. The thermal printhead of claim 1. [Appendix 3] The inclined portion further includes a third inclined surface (143) connected to the top surface and inclined at a third inclination angle with respect to the main surface. 3. The thermal printhead of claim 1 or 2. [Appendix 4] the first tilt angle and the third tilt angle are equal; 4. The thermal printhead of claim 3. [Appendix 5] The second inclined surface and the third inclined surface are connected to each other. 5. The thermal printhead of claim 3 or 4. [Appendix 6, Second embodiment, Figure 18] The inclined portion further includes a parallel surface (144) that is connected to the second inclined surface and the third inclined surface and is parallel to the main surface. 5. The thermal printhead of claim 3 or 4. [Appendix 7, Figure 6] The dimension (W1) of the convex portion in the sub-scanning direction is between two and ten times the dimension (W2) of the top portion in the sub-scanning direction. 7. A thermal printhead according to any one of claims 1 to 6. [Appendix 8] the single-crystal semiconductor is made of Si, The main surface is a (100) surface. 8. A thermal printhead according to any one of claims 1 to 7. [Appendix 9, Figure 6] the ratio of the thickness direction dimension (H2) of the heat storage layer to the sub-scanning direction dimension (W2) is 0.05 or more and 0.25 or less; 9. A thermal printhead according to any one of claims 1 to 8. [Appendix 10] The dimension in the thickness direction of the heat storage layer is 15 μm or more and 60 μm or less. 10. A thermal printhead according to any one of claims 1 to 9. [Appendix 11] the heat storage layer is formed over the entire width of the top surface in the sub-scanning direction; 11. A thermal printhead according to any one of claims 1 to 10. [Appendix 12, Figure 7] a preparation step (S10) of preparing a substrate made of a single crystal semiconductor; a first etching step (S20) of performing a first anisotropic etching on the base material to form a main surface facing one side in the thickness direction, a convex portion protruding from the main surface, and two grooves recessed from a top surface of the convex portion parallel to the main surface and extending in the main scanning direction; a heat storage layer forming step (S30) of forming a heat storage layer by disposing and firing glass paste in the area between the two grooves on the top surface; a second etching step (S40) of performing a second anisotropic etching on the base material to remove a portion of the convex portion, thereby forming, in the convex portion, a top surface which is a region of the top surface sandwiched between the two grooves, a first inclined surface which is connected to the main surface and is inclined at a first inclination angle with respect to the main surface, and a second inclined surface which is interposed between the first inclined surface and the top surface and is inclined at a second inclination angle with respect to the main surface; a heat generating portion forming step (S70) of forming a plurality of heat generating portions arranged in the main scanning direction on the heat storage layer; Equipped with A method for manufacturing a thermal printhead. [Appendix 12-1] a preparation step of preparing a substrate made of a single crystal semiconductor; a first etching step of performing a first anisotropic etching on the base material to form a main surface facing one side in a thickness direction, a convex portion protruding from the main surface, and two grooves recessed from a top surface of the convex portion parallel to the main surface and extending in a main scanning direction; a second etching step of performing a second anisotropic etching on the base material to remove a portion of the convex portion, thereby forming, in the convex portion, a top surface which is a region of the top surface sandwiched between the two grooves, a first inclined surface which is connected to the main surface and is inclined at a first inclination angle (55°) with respect to the main surface, and a second inclined surface which is interposed between the first inclined surface and the top surface and is inclined at a second inclination angle (31°) with respect to the main surface; a heat storage layer forming step of forming a heat storage layer by disposing a glass paste on the top surface and firing it; a heat generating portion forming step of forming a plurality of heat generating portions arranged in the main scanning direction on the heat storage layer; Equipped with A method for manufacturing a thermal printhead. [Appendix 13] In the second etching step, a third inclined surface is further formed in the convex portion, the third inclined surface being connected to the top surface and inclined at the first inclination angle with respect to the main surface. A method for manufacturing a thermal printhead according to claim 12. [Appendix 14] The method further includes an insulating layer forming step (S60) that is performed between the second etching step and the heat generating portion forming step, and that forms an insulating layer that covers the heat storage layer and the base material. A method for manufacturing a thermal printhead according to claim 12 or 13. [Appendix 15] The method further includes a re-firing step (S50) that is performed between the second etching step and the insulating layer forming step, in which the heat storage layer is melted by firing and then solidified. A method for manufacturing a thermal printhead according to claim 14. [Explanation of symbols]

[0081] A1 to A5: Thermal print head 1: Head board 10: Base material 11: Main surface 12: Convex part 13:Top 131:Top surface 14: Inclined part 141: First slope 142: Second slope 143: Third slope 144: Parallel planes 145: 4th slope 15: Heat storage layer 151: Round section 19: Insulating layer 2:Protective layer 21: Pad opening 3: Electrode layer 31: Individual electrode 311: Electrode pad section 32: Common electrode 323:Common section 324: Comb teeth 4:Resistor layer 41: Heat generating part 5: Connection board 59: Connector 61: Wire 62: Wire 7: Driver IC 78: Protective resin 8: Heat dissipation material 99: Platen roller 10A: Base material 11A: Main surface 12A: Convex part 13A: Top 131A: Top 132A: Groove 14A: Inclined part 141A: Slope 3A: Conductive film 4A:Resistor film 91, 93: Mask layer 92: Slit

Claims

1. a substrate having a main surface facing in one direction in a thickness direction and made of a single crystal semiconductor; a resistor layer formed on the main surface and including a plurality of heat generating portions arranged in a main scanning direction; an insulating layer formed between the substrate and the resistor layer; a heat storage layer formed between the base material and the plurality of heat generating portions and being a glaze made of a glass material; Equipped with the base material includes a protrusion protruding from the main surface and extending in the main scanning direction; The convex portion is a top portion having a top surface parallel to the main surface; an inclined portion that is connected to the top portion and the main surface and is inclined with respect to the main surface; Equipped with The inclined portion is a first inclined surface connected to the main surface and inclined at a first inclination angle with respect to the main surface; a second inclined surface interposed between the first inclined surface and the top surface and inclined at a second inclination angle with respect to the main surface; a third inclined surface connected to the top surface and inclined at a third inclination angle with respect to the main surface; Equipped with The heat storage layer is formed only on the top surface. Thermal print head.

2. The first tilt angle is greater than the second tilt angle.

2. The thermal printhead of claim 1.

3. the first tilt angle and the third tilt angle are equal; 3. The thermal printhead according to claim 1 or 2.

4. the second inclined surface and the third inclined surface are connected to each other; 4. The thermal printhead according to claim 1.

5. the inclined portion further includes a parallel surface that is connected to the second inclined surface and the third inclined surface and is parallel to the main surface.

4. The thermal printhead according to claim 1.

6. the dimension of the convex portion in the sub-scanning direction is between two and ten times the dimension of the apex portion in the sub-scanning direction; 6. A thermal printhead according to claim 1.

7. the single-crystal semiconductor is made of Si, The main surface is a (100) surface.

7. The thermal printhead according to claim 1.

8. a ratio of the thickness direction dimension of the heat storage layer to the sub-scanning direction dimension is 0.05 or more and 0.25 or less; 8. The thermal printhead according to claim 1.

9. The dimension of the heat storage layer in the thickness direction is 15 μm or more and 60 μm or less.

9. A thermal printhead according to claim 1.

10. the heat storage layer is formed over the entire width of the top surface in the sub-scanning direction; 10. The thermal printhead according to claim 1.

11. a preparation step of preparing a substrate made of a single crystal semiconductor; a first etching step of performing a first anisotropic etching on the base material to form a main surface facing one side in a thickness direction, a convex portion protruding from the main surface, and two grooves recessed from a top surface of the convex portion parallel to the main surface and extending in a main scanning direction; a heat storage layer forming step of forming a heat storage layer by disposing a glass paste in the area between the two grooves on the top surface and firing the paste; a second etching step of performing a second anisotropic etching on the base material to remove a portion of the convex portion, thereby forming, in the convex portion, a top surface which is a region of the top surface sandwiched between the two grooves, a first inclined surface which is connected to the main surface and is inclined at a first inclination angle with respect to the main surface, and a second inclined surface which is interposed between the first inclined surface and the top surface and is inclined at a second inclination angle with respect to the main surface; a heat generating portion forming step of forming a plurality of heat generating portions arranged in the main scanning direction on the heat storage layer; Equipped with In the second etching step, a third inclined surface is further formed in the convex portion, the third inclined surface being connected to the top surface and inclined at the first inclination angle with respect to the main surface. A method for manufacturing a thermal printhead.

12. The method further includes an insulating layer forming step, which is performed between the second etching step and the heat generating portion forming step, and which forms an insulating layer that covers the heat storage layer and the base material. The method for manufacturing the thermal printhead according to claim 11.

13. The method further includes a re-firing step, which is performed between the second etching step and the insulating layer forming step, in which the heat storage layer is melted by firing and then solidified. The method for manufacturing a thermal printhead according to claim 12.

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