Thermal printhead and method for manufacturing thermal printhead

Abstract

The invention provides a thermal printing head and a manufacturing method of the thermal printing head. The thermal print head includes a substrate, an insulating layer, a wiring layer, a resistor layer, and a protective layer. The substrate has a first surface and a second surface opposite to the first surface. The first surface is provided with a protruding part which protrudes towards the opposite side of the second surface and extends along the first direction in a plan view. The insulating layer is disposed on the first surface. The wiring layer is disposed on the insulating layer with the resistor layer interposed therebetween. The wiring layer has a bonding pad. The wiring layer is made of aluminum or an aluminum alloy. The protective layer is disposed on the insulating layer so as to cover the wiring layer. The protective layer is provided with an opening part which exposes the bonding pad. A width of the opening portion in the first direction is greater than a width of the bonding pad in the first direction. According to the invention, poor wire bonding can be suppressed.

Description

Technical Field

[0001] The invention relates to a thermal print head and a method for manufacturing the thermal print head. Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2022-165673 (Patent Document 1) describes a thermal print head. The thermal print head described in Patent Document 1 includes a substrate, an insulating layer, a wiring layer, a resistor layer, a protective layer, and a plating layer.

[0003] The insulating layer is arranged on the substrate. The wiring layer is arranged on the insulating layer via the resistor layer. The wiring layer is made of copper. The wiring layer has a bonding pad. The protective layer is arranged on the insulating layer in a manner covering the wiring layer. An opening portion penetrating the protective layer is formed in the protective layer. The bonding pad is partially exposed from the opening portion. The plating layer is arranged on the bonding pad exposed from the opening portion. The bonding pad is wire bonded via the plating layer. Summary of the invention

[0004] In order to reduce manufacturing costs, it is considered to change the constituent material of the wiring layer from copper to aluminum (or aluminum alloy). As a result, it is not necessary to form a plating layer on the bonding pad. However, since the upper surface of the bonding pad is located below the upper surface of the protective layer, there is a situation where the capillary contacts the opening edge of the opening when wire bonding is performed. The contact between the capillary and the opening edge of the opening becomes a cause of poor wire bonding.

[0005] The thermal print head of the present invention includes a substrate, an insulating layer, a wiring layer, a resistor layer and a protective layer. The substrate has a first surface and a second surface which is the opposite surface of the first surface. A protrusion is formed on the first surface, which protrudes to the opposite side of the second surface and extends along the first direction when viewed from above. The insulating layer is arranged on the first surface. The wiring layer is arranged on the insulating layer through the resistor layer. The wiring layer has a bonding pad. The wiring layer is made of aluminum or an aluminum alloy. The protective layer is arranged on the insulating layer in a manner covering the wiring layer. An opening portion for exposing the bonding pad is formed in the protective layer. The width of the opening portion in the first direction is greater than the width of the bonding pad in the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a top view of the thermal print head 100 .

[0007] Figure 2A yes Figure 1 Cross-sectional view of IIA-IIA in FIG.

[0008] Figure 2B yes Figure 1 Cross-sectional view of IIB-IIB in FIG.

[0009] Figure 3 yes Figure 1 Cross-sectional view of III-III in FIG.

[0010] Figure 4 It is a top view of the thermal print head 100 in a state where the bonding wire 60 is bonded.

[0011] Figure 5 It is a manufacturing process diagram of the thermal print head 100.

[0012] Figure 6 It is a first cross-sectional view for explaining the raised portion forming step S2.

[0013] Figure 7 It is a second cross-sectional view for explaining the raised portion forming step S2.

[0014] Figure 8 It is a third cross-sectional view for explaining the protrusion forming step S2.

[0015] Fig. 9 It is a cross-sectional view for explaining the insulating layer forming step S3.

[0016] Fig.10 It is a first cross-sectional view for explaining the wiring layer forming step S4.

[0017] Fig.11 It is a second cross-sectional view for explaining the wiring layer forming step S4.

[0018] Fig.12 It is a third cross-sectional view for explaining the wiring layer forming step S4.

[0019] Fig.13 It is a fourth cross-sectional view for explaining the wiring layer forming step S4.

[0020] Fig.14 It is a fifth cross-sectional view for explaining the wiring layer forming step S4.

[0021] Fig.15 It is a cross-sectional view explaining the protective layer forming step S5.

[0022] Fig.16 is a top view of the thermal print head 200 .

[0023] Fig.17 yes Fig.16 Cross-sectional view at XVII-XVII in FIG. DETAILED DESCRIPTION

[0024] The details of the embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description will not be given. The thermal print head of the embodiment is assumed to be a thermal print head 100 .

[0025] (Structure of Thermal Print Head 100)

[0026] Next, the structure of the thermal print head 100 will be described.

[0027] Figure 1 is a top view of the thermal print head 100. Figure 1 In the figure, the removed portions of the individual wiring 31 and the common wiring 32 are omitted from illustration. Figure 2A yes Figure 1 Cross-sectional view of IIA-IIA in FIG. Figure 2B yes Figure 1 Cross-sectional view of IIB-IIB in FIG. Figure 3 yes Figure 1 The cross-sectional view of III-III in FIG. Figures 1 to 3 As shown, the thermal print head 100 includes a substrate 10 , an insulating layer 20 , a wiring layer 30 , a resistor layer 40 , and a protective layer 50 .

[0028] The constituent material of the substrate 10 is, for example, single crystal silicon. The substrate 10 has a first surface 10a and a second surface 10b. The first surface 10a and the second surface 10b are end surfaces in the thickness direction of the substrate 10. The second surface 10b is the opposite surface of the first surface 10a.

[0029] The first surface 10a has a raised portion 11. The first surface 10a protrudes toward the opposite side of the second surface 10b in the raised portion 11. The raised portion 11 extends along the first direction DR1 in a plan view.

[0030] The insulating layer 20 includes, for example, a first insulating layer 21, a glaze layer 22, and a second insulating layer 23. The first insulating layer 21 is formed on the first surface 10a. In addition, the first insulating layer 21 is also arranged on the second surface 10b. The constituent material of the first insulating layer 21 is, for example, silicon oxide. The glaze layer 22 is arranged on the top surface of the protrusion 11 via the first insulating layer 21. The constituent material of the glaze layer 22 is, for example, glass. The second insulating layer 23 is arranged on the first insulating layer 21 in a manner covering the glaze layer 22. The constituent material of the second insulating layer 23 is, for example, silicon oxide.

[0031] The wiring layer 30 is disposed on the insulating layer 20 via the resistor layer 40. The wiring layer 30 is made of aluminum or an aluminum alloy, for example. The resistor layer 40 is made of tantalum nitride, for example. An intermediate layer 41 may be interposed between the wiring layer 30 and the resistor layer 40. The intermediate layer 41 is made of titanium, for example.

[0032] The wiring layer 30 includes a plurality of individual wirings 31 , a plurality of common wirings 32 , and a common electrode 33 .

[0033] The plurality of independent wirings 31 are arranged along the first direction DR1 in a plan view. One end of the independent wiring 31 in the second direction DR2 overlaps the protrusion 11 in a plan view. The other end of the independent wiring 31 in the second direction DR2 has a bonding pad 31a. In addition, the second direction DR2 is a direction orthogonal to the first direction DR1 in a plan view.

[0034] When viewed in a cross section orthogonal to the second direction DR2, the bonding pad 31a has an upper surface, a bottom surface, and a side surface connected to the upper surface and the bottom surface. The width of the bottom surface of the bonding pad 31a in the first direction DR1 is preferably 1.1 times or more the width of the upper surface of the bonding pad 31a in the first direction DR1. It is preferred that aluminum chloride is substantially absent on the side surface of the bonding pad 31a. From another point of view, it is preferred that the concentration of aluminum chloride on the side surface of the bonding pad 31a is not detected. The concentration of aluminum chloride on the side surface of the bonding pad 31a is measured by energy dispersive X-ray spectroscopy. The width of the bonding pad 31a in the first direction DR1 is preferably 100 μm or more.

[0035] A plurality of common wirings 32 are arranged along the first direction DR1 in a plan view. The common wiring 32 is arranged between two independent wirings 31 adjacent to each other in the first direction DR1. One end of the common wiring 32 in the second direction DR2 overlaps with the raised portion 11 in a plan view. One end of the common wiring 32 in the second direction DR2 is connected to one end of the independent wiring 31 in the second direction DR2. The other end of the common wiring 32 in the second direction DR2 is connected to the common electrode 33. The common electrode 33 extends along the first direction DR1 in a plan view. A common potential is supplied to the common electrode 33.

[0036] The independent wiring 31 is partially removed at a position overlapping with the raised portion 11 when viewed from above. The intermediate layer 41 and the resistor layer 40 are exposed from the removed portion of the independent wiring 31. The intermediate layer 41 exposed from the removed portion of the independent wiring 31 is partially removed, and the resistor layer 40 is exposed from the removed portion of the intermediate layer 41. Similarly, the common wiring 32 is partially removed at a position overlapping with the raised portion 11 when viewed from above. The intermediate layer 41 and the resistor layer 40 are exposed from the removed portion of the common wiring 32. The intermediate layer 41 exposed from the removed portion of the common wiring 32 is partially removed, and the resistor layer 40 is exposed from the removed portion of the intermediate layer 41.

[0037] The protective layer 50 is made of silicon nitride, for example, and is disposed on the insulating layer 20 to cover the wiring layer 30. The protective layer 50 is also disposed on the resistor layer 40 and the intermediate layer 41 in the removed portions of the individual wiring 31 and the common wiring 32.

[0038] An opening 51 is formed in the protective layer 50. The opening 51 penetrates the protective layer 50 in the thickness direction. When viewed from above, the width of the opening 51 in the second direction DR2 is greater than the width of the opening 51 in the first direction DR1, for example. When viewed from above, the width of the opening 51 in the first direction DR1 is greater than the width of the bonding pad 31a in the first direction DR1. From another point of view, both ends of the bonding pad 31a in the first direction DR1 are exposed from the opening 51.

[0039] Figure 4 FIG. 1 is a top view of the thermal print head 100 in a state where the bonding wire 60 is bonded. Figure 4 As shown, one end of the bonding wire 60 is bonded to the bonding pad 31a. Although not shown, the other end of the bonding wire 60 is bonded to a bonding pad of a driver IC (Integrated Circuit). Thus, the thermal print head 100 is electrically connected to the driver IC.

[0040] The driver IC supplies potentials to the plurality of independent wirings 31 individually via the bonding wires 60. As a result, current flows through one independent wiring 31 supplied with potential and one common wiring 32 connected to the one independent wiring 31. Current flows through the resistor layer 40 in the removed portion of the independent wiring 31 and the removed portion of the common wiring 32. As a result, the resistor layer 40 exposed from the removed portion of the one independent wiring 31 supplied with potential and the resistor layer 40 exposed from the removed portion of the common wiring 32 connected to the one independent wiring 31 generate heat, respectively, and the heat is transferred to the paper, thereby printing on the paper.

[0041] (Method of Manufacturing Thermal Print Head 100)

[0042] Next, a method for manufacturing a thermal print head will be described.

[0043] Figure 5 FIG. 1 is a manufacturing process diagram of the thermal print head 100. Figure 5 As shown, the method for manufacturing the thermal print head 100 includes a preparation step S1, a protrusion forming step S2, an insulating layer forming step S3, a wiring layer forming step S4, a protective layer forming step S5, and a singulation step S6. In the preparation step S1, the substrate 10 is prepared. After the preparation step S1, the protrusion forming step S2 is performed.

[0044] In the raised portion forming step S2 , the raised portion 11 is formed on the first surface 10 a . Figure 6 1 is a first cross-sectional view for explaining the raised portion forming step S2. Figure 6As shown, in the protrusion forming step S2, first, a hard mask HM is formed on the surface of the substrate 10. The constituent material of the hard mask HM is, for example, silicon nitride. The hard mask HM is formed, for example, by a reduced pressure CVD (Chemical Vapor Deposition) method. Figure 7 2 is a second cross-sectional view for explaining the raised portion forming step S2. Figure 7 As shown, in the protrusion forming step S2, secondly, the hard mask HM located on the first surface 10a is partially removed by RIE (Reactive Ion Etching) using a resist pattern formed by photolithography as a mask. As a result, the hard mask HM remains only at a position corresponding to the top surface of the protrusion 11 on the first surface 10a. Figure 8 3 is a third cross-sectional view for explaining the raised portion forming step S2. Figure 8 As shown, in the ridge forming step S2, thirdly, the first surface 10a is wet-etched using a potassium hydroxide aqueous solution using the hard mask HM as a mask. Although not shown, after the wet etching, the hard mask HM is removed using hydrofluoric acid. After the ridge forming step S2, the insulating layer forming step S3 is performed.

[0045] Fig. 9 2 is a cross-sectional view illustrating the insulating layer forming step S3. Fig. 9 As shown, in the insulating layer forming step S3, the insulating layer 20 is formed. In the insulating layer forming step S3, first, a first insulating layer 21 is formed on the surface of the substrate 10 by thermal oxidation. Second, a glaze layer 22 is formed on the top surface of the protrusion 11 with the first insulating layer 21 sandwiched therebetween. The glaze layer 22 is formed by applying a paste containing glass to the top surface of the protrusion 11 via the first insulating layer 21 and firing the applied paste. Third, a second insulating layer 23 is formed on the first insulating layer 21 located on the first surface 10a in a manner covering the glaze layer 22. The second insulating layer 23 is formed, for example, by a plasma CVD method using TEOS (Tetra Eth Oxy Silane). After the insulating layer forming step S3, a wiring layer forming step S4 is performed.

[0046] Fig.10 1 is a first cross-sectional view for explaining the wiring layer forming step S4. Fig.10 As shown, in the wiring layer forming step S4, first, the constituent material of the resistor layer 40, the constituent material of the intermediate layer 41, and the constituent material of the wiring layer 30 are sequentially formed on the insulating layer 20. This film formation is performed by, for example, sputtering.

[0047] Fig.11 2 is a second cross-sectional view for explaining the wiring layer forming step S4. Fig.11As shown, in the wiring layer forming step S4, secondly, the constituent material of the wiring layer 30 after film formation is patterned by wet etching using a resist pattern formed by photolithography as a mask. Thus, the independent wiring 31, the common wiring 32, and the common electrode 33 are formed. At this stage, the independent wiring 31 and the common wiring 32 are not partially removed. In addition, since the wiring layer 30 is patterned by wet etching, the width of the bottom surface of the bonding pad 31a in the first direction DR1 becomes more than 1.1 times the width of the upper surface of the bonding pad 31a in the first direction DR1, and aluminum chloride does not substantially exist on the side surface of the bonding pad 31a.

[0048] Fig.12 3 is a third cross-sectional view for explaining the wiring layer forming step S4. Fig.12 As shown, in the wiring layer forming step S4, thirdly, the constituent material of the formed intermediate layer 41 is patterned by wet etching using the individual wirings 31, the common wirings 32, and the common electrodes 33 as masks. Thus, the intermediate layer 41 is formed. Fig.13 4 is a fourth cross-sectional view for explaining the wiring layer forming step S4. Fig.13 As shown, in the wiring layer forming step S4, in the fourth step, the independent wiring 31 and the common wiring 32 located at a position overlapping with the protrusion 11 in a plan view are partially removed by, for example, wet etching using a resist pattern formed by photolithography as a mask. In addition, along with this etching, the intermediate layer 41 exposed from the removed portion of the independent wiring 31 and the removed portion of the common wiring 32 is also partially removed.

[0049] Fig.14 4 is a fifth cross-sectional view for explaining the wiring layer forming step S4. Fig.14 As shown, in the wiring layer forming step S4, for example, the constituent material of the resistor body layer 40 after film formation is patterned by RIE using a resist pattern formed by photolithography as a mask. At this time, the constituent material of the resistor body layer 40 after film formation is not removed in the removed portion of the independent wiring 31 and the removed portion of the common wiring 32. After the wiring layer forming step S4, the protective layer forming step S5 is performed.

[0050] Fig.15 2 is a cross-sectional view illustrating the protective layer forming step S5. Fig.15 As shown, in the protective layer forming step S5, a protective layer 50 is formed. In the protective layer forming step S5, first, the protective layer 50 is formed by, for example, a CVD method. Second, an opening 51 is formed by, for example, RIE using a resist pattern formed by photolithography as a mask so as to expose the bonding pad 31a. After the protective layer forming step S5, the singulation step S6 is performed.

[0051] In the singulation step S6, the substrate 10 is cut to form Figures 1 to 3 The structure of the thermal print head 100 is shown.

[0052] The thermal print head 100 is subjected to the wire bonding process S7. In the wire bonding process S7, a capillary is used. The bonding wire 60 is held by the capillary. The diameter of the capillary is preferably larger than the width of the bonding pad 31a in the first direction DR1. The difference between the width of the bonding pad 31a in the first direction DR1 and the diameter of the capillary is preferably 20 μm or more.

[0053] (Variation Example)

[0054] In the thermal print head 100, the top surface of the raised portion 11 may also be formed of a plurality of planes. In addition, in the thermal print head 100, the insulating layer 20 may not have the glaze layer 22. In this case, in the raised portion forming step S2, after the substrate 10 is wet-etched with a potassium hydroxide aqueous solution, wet etching with TMAH (tetramethylammonium hydroxide) is performed. Thus, the top surface of the raised portion 11 is composed of a plurality of planes.

[0055] (Effect of thermal print head 100)

[0056] Hereinafter, the effects of the thermal print head 100 will be described in comparison with a comparative example. The thermal print head of the comparative example is referred to as a thermal print head 200 .

[0057] Fig.16 is a top view of the thermal print head 200 . Fig.17 yes Fig.17 The cross-sectional view at XVII-XVII in FIG. Fig.16 and Fig.17 As shown, in the thermal print head 200, the width of the opening 51 in the first direction DR1 is smaller than the width of the bonding pad 31a in the first direction DR1. That is, both ends of the bonding pad 31a in the first direction DR1 of the thermal print head 200 are covered by the protective layer 50, and the bonding pad 31a is not completely exposed from the opening 51.

[0058] In the thermal print head 200, the width of the bottom surface of the bonding pad 31a in the first direction DR1 is less than 1.1 times the width of the top surface of the bonding pad 31a in the first direction DR1, and aluminum chloride remains on the side surface of the bonding pad 31a. That is, the patterning of the wiring layer 30 is formed by dry etching using a chlorine-based gas. In these points, the structure of the thermal print head 200 is different from that of the thermal print head 100.

[0059] In the thermal print head 200, the upper surface of the bonding pad 31a is located below the upper surface of the protective layer 50, and the width of the opening 51 in the first direction DR1 is smaller than the width of the bonding pad 31a in the first direction DR1. Therefore, when wire bonding is performed in the thermal print head 200, the capillary contacts the opening edge of the opening 51, and sometimes the bonding between the bonding wire 60 and the bonding pad 31a is poor.

[0060] In the thermal print head 100, the upper surface of the bonding pad 31a is also located below the upper surface of the protective layer 50. However, in the thermal print head 100, the width of the opening 51 in the first direction DR1 is larger than the width of the bonding pad 31a in the first direction DR1, so when wire bonding is performed, it is difficult for the capillary to contact the opening edge of the opening 51. In this way, according to the thermal print head 100, it is possible to suppress wire bonding defects.

[0061] In addition, in the thermal print head 200, since aluminum chloride remains on the side of the bonding pad 31a, the width of the opening 51 in the first direction DR1 cannot be made larger than the width of the bonding pad 31a in the first direction DR1. This is because if the width of the opening 51 in the first direction DR1 is made larger than the width of the bonding pad 31a in the first direction DR1 in the thermal print head 200 (if the side of the bonding pad 31a is exposed from the protective layer 50), the bonding pad 31a will be corroded due to the influence of aluminum chloride remaining on the side.

[0062] (Note)

[0063] The present invention includes the following structures.

[0064] <Note 1>

[0065] A thermal print head, comprising:

[0066] substrate;

[0067] Insulation layer;

[0068] Wiring layer;

[0069] a resistor body layer; and

[0070] Protective layer,

[0071] The substrate has a first surface and a second surface which is an opposite surface to the first surface.

[0072] A raised portion is formed on the first surface, the raised portion protruding to the side opposite to the second surface and extending along a first direction in a plan view,

[0073] The insulating layer is disposed on the first surface,

[0074] The wiring layer is arranged on the insulating layer via the resistor layer.

[0075] The wiring layer has a bonding pad,

[0076] The wiring layer is made of aluminum or aluminum alloy.

[0077] The protective layer is arranged on the insulating layer in a manner covering the wiring layer,

[0078] An opening is formed in the protective layer to expose the bonding pad.

[0079] A width of the opening in the first direction is greater than a width of the bonding pad in the first direction.

[0080] <Note 2>

[0081] The thermal print head according to Supplementary Note 1, wherein the bonding pad has an upper surface and a bottom surface which is an opposite surface to the upper surface,

[0082] The width of the bottom surface in the second direction is at least 1.1 times the width of the upper surface in the second direction,

[0083] The second direction is orthogonal to the first direction in a plan view.

[0084] <Note 3>

[0085] The thermal print head according to Supplement 1 or 2, wherein, in a cross-sectional view orthogonal to the second direction, the bonding pad has an upper surface, a bottom surface which is an opposite surface of the upper surface, and a side surface connected to the upper surface and the bottom surface,

[0086] On the side, no aluminum chloride concentration was detected.

[0087] The second direction is orthogonal to the first direction in a plan view.

[0088] <Note 4>

[0089] The thermal print head as described in any one of Supplementary Notes 1 to 3, wherein the width of the opening in the first direction is 100 μm or more.

[0090] <Note 5>

[0091] A method for manufacturing a thermal print head, comprising: preparing a substrate having a first surface and a second surface which is an opposite surface to the first surface;

[0092] forming, on the first surface, a raised portion that protrudes toward a side opposite to the second surface and extends along a first direction when viewed from above;

[0093] forming an insulating layer on the first surface;

[0094] forming a wiring layer on the insulating layer via a resistor layer; and

[0095] forming a protective layer on the insulating layer so as to cover the wiring layer,

[0096] The wiring layer is made of aluminum or aluminum alloy.

[0097] The wiring layer has a bonding pad,

[0098] An opening is formed in the protective layer to expose the bonding pad.

[0099] A width of the opening in the first direction is greater than a width of the bonding pad in the first direction.

[0100] <Note 6>

[0101] According to the manufacturing method of the thermal print head described in Note 5, the process of forming the wiring layer includes: a process of forming a film of the constituent material of the wiring layer; and a process of patterning the constituent material of the wiring layer after the film formation by wet etching using a resist pattern as a mask.

[0102] <Note 7>

[0103] The method for manufacturing a thermal print head according to Appendix 5 or 6, further comprising the step of wire bonding the bonding pad using a capillary.

[0104] The width of the opening in the first direction is greater than the diameter of the capillary.

[0105] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. A thermal print head, characterized in that: include: substrate; Insulation layer; Wiring layer; Resistor body layer; and Protective layer, The substrate has a first surface and a second surface which is an opposite surface to the first surface. A raised portion is formed on the first surface, the raised portion protruding to the side opposite to the second surface and extending along a first direction in a plan view, The insulating layer is disposed on the first surface, The wiring layer is arranged on the insulating layer via the resistor layer. The wiring layer has a bonding pad, The wiring layer is made of aluminum or aluminum alloy. The protective layer is arranged on the insulating layer in a manner covering the wiring layer, An opening is formed in the protective layer to expose the bonding pad. A width of the opening in the first direction is greater than a width of the bonding pad in the first direction.

2. The thermal print head according to claim 1, wherein: The bonding pad has an upper surface and a bottom surface which is an opposite surface of the upper surface, The width of the bottom surface in the second direction is at least 1.1 times the width of the upper surface in the second direction, The second direction is orthogonal to the first direction in a plan view.

3. The thermal print head according to claim 1, wherein: In a cross-sectional view orthogonal to the second direction, the bonding pad has an upper surface, a bottom surface which is an opposite surface of the upper surface, and a side surface connected to the upper surface and the bottom surface, On the side, no aluminum chloride concentration was detected. The second direction is orthogonal to the first direction in a plan view.

4. The thermal print head according to any one of claims 1 to 3, characterized in that: The width of the opening in the first direction is greater than or equal to 100 μm.

5. A method for manufacturing a thermal print head, characterized in that: include: A step of preparing a substrate having a first surface and a second surface which is an opposite surface to the first surface; forming, on the first surface, a raised portion that protrudes toward a side opposite to the second surface and extends along a first direction when viewed from above; forming an insulating layer on the first surface; forming a wiring layer on the insulating layer via a resistor layer; and forming a protective layer on the insulating layer so as to cover the wiring layer, The wiring layer is made of aluminum or aluminum alloy. The wiring layer has a bonding pad, An opening is formed in the protective layer to expose the bonding pad. A width of the opening in the first direction is greater than a width of the bonding pad in the first direction.

6. The method for manufacturing a thermal print head according to claim 5, wherein: The step of forming the wiring layer includes: forming a film of a constituent material of the wiring layer; and patterning the formed constituent material of the wiring layer by wet etching using a resist pattern as a mask.

7. The method for manufacturing a thermal print head according to claim 5 or 6, characterized in that: The method further includes the step of performing wire bonding on the bonding pad using a capillary. The width of the opening in the first direction is greater than the diameter of the capillary.

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