JP2023109032A - Thermal print head and manufacturing method of the same - Google Patents

Abstract

To provide a thermal print head which can achieve improvement of heat accumulation performance of a substrate to inhibit deterioration of printing efficiency, and to provide a manufacturing method of the thermal print head.SOLUTION: A thermal print head A10 includes: a substrate 1 having a major surface 11 directed in a first direction z; a resistor layer 3 including multiple heating parts 31 and disposed on the major surface 11; and a wiring layer 4 which has electric continuity with the multiple heating parts 31 and is formed contacting with the resistor layer 3. The substrate 1 includes: a first layer 101 including the major surface 11; a second layer 102 located at the opposite side of the resistor layer 3 with respect to the first layer 101 in the first direction z; and an intermediate layer 103 located between the first layer 101 and the second layer 102. Heat conductivity of the intermediate layer 103 is lower than heat conductivity of each of the first layer 101 and the second layer 102.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to thermal printheads and methods of manufacturing the same.

Patent Document 1 discloses a thermal printhead having a substrate made of a material containing silicon. A substrate of the thermal printhead has a main surface and a convex portion extending in the main scanning direction and protruding from the main surface. As shown in FIG. 6 of Patent Document 1, etc., the plurality of heat generating portions are arranged along the main scanning direction on the convex portion. According to such a configuration, since the recording medium can be accurately brought into contact with the convex portion in which the plurality of heat generating portions are arranged, an improvement in print quality can be expected.

However, the thermal conductivity of the substrate of the thermal printhead disclosed in Patent Document 1 is approximately the same as that of the substrate containing aluminum nitride. Therefore, heat is easily conducted in the substrate of the thermal print head. Therefore, when the thermal print head is used in cold climates, the temperature of the plurality of heat-generating portions arranged along the main scanning direction on the convex portion tends to decrease. As a result, the printing speed decreases, and there is concern that the printing efficiency will decrease.

JP 2019-166824 A

In view of the circumstances described above, an object of the present disclosure is to provide a thermal printhead capable of suppressing a decrease in printing efficiency by improving the heat storage performance of the substrate, and a method of manufacturing the same.

A thermal printhead provided by a first aspect of the present disclosure includes a substrate having a principal surface facing a first direction, and a plurality of heat generating portions arranged along a second direction perpendicular to the first direction. and a resistor layer disposed on the main surface; and a wiring layer electrically connected to the plurality of heat generating portions and disposed in contact with the resistor layer, wherein the substrate includes a first layer including a main surface, a second layer located on the opposite side of the resistor layer with respect to the first layer in the first direction, and between the first layer and the second layer and an intermediate layer located, wherein the thermal conductivity of said intermediate layer is lower than the thermal conductivity of each of said first layer and said second layer.

A method of manufacturing a thermal printhead provided by a second aspect of the present disclosure includes forming a substrate having a major surface facing in a first direction; forming a resistor layer on the main surface, the resistor layer including a plurality of heat generating portions arranged in a line; and forming a wiring layer electrically connected to the plurality of heat generating portions in contact with the resistor layer. , the substrate includes a first substrate including the main surface and having a first surface facing in the first direction opposite to the main surface; and a second surface facing the first surface. and a second substrate, wherein the step of forming the substrate comprises: forming a coating layer covering at least one of the first surface and the second surface; laminating a first substrate to the second substrate, wherein the thermal conductivity of the coating layer is lower than the thermal conductivity of each of the first substrate and the second substrate.

According to the thermal printhead and the method for manufacturing the same according to the present disclosure, it is possible to suppress deterioration in printing efficiency by improving the heat storage performance of the substrate.

Other features and advantages of the present disclosure will become more apparent from the detailed description provided below with reference to the accompanying drawings.

1 is a plan view of a thermal print head according to a first embodiment of the present disclosure; FIG. 2 is a plan view of the main part of the thermal print head shown in FIG. 1. FIG. 3 is a partially enlarged view of FIG. 2. FIG. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. FIG. 5 is a cross-sectional view of the essential part of the thermal print head shown in FIG. 6 is a partially enlarged view of FIG. 5. FIG. 7A and 7B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 8A and 8B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 9A and 9B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 10A and 10B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 11A and 11B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 12A and 12B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 13A and 13B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 14A and 14B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 15A and 15B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 16A and 16B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 17A and 17B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. FIG. 18 is a cross-sectional view of main parts of a thermal print head according to a second embodiment of the present disclosure; 19 is a partially enlarged view of FIG. 18. FIG. 20A to 20C are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. 21A to 21C are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. FIG. 22 is a cross-sectional view of main parts of a thermal print head according to a third embodiment of the present disclosure; 23A and 23B are cross-sectional views for explaining the manufacturing process of the main part of the thermal print head shown in FIG. FIG. 24 is a cross-sectional view of main parts of a thermal print head according to a fourth embodiment of the present disclosure; 25 is a partially enlarged view of FIG. 24. FIG.

A mode for carrying out the present disclosure will be described based on the accompanying drawings.

[First embodiment]
A thermal print head A10 according to the first embodiment of the present disclosure will be described with reference to FIGS. 1 to 6. FIG. The thermal print head A10 constitutes a main part of a thermal printer B10, which will be described later. The thermal printhead A10 is composed of main parts and auxiliary parts. A main part of the thermal printhead A10 includes a substrate 1, an insulating layer 2, a resistor layer 3, a wiring layer 4 and a protective layer 5. As shown in FIG. The accompanying portion of the thermal print head A10 includes a wiring board 71, a heat dissipation member 72, a plurality of driving elements 73, a plurality of first wires 74, a plurality of second wires 75, a sealing resin 76 and a connector 77. Here, in FIG. 1, illustration of the protective layer 5, the plurality of first wires 74, the plurality of second wires 75, and the sealing resin 76 is omitted for convenience of understanding. 2 and 3, illustration of the protective layer 5 is omitted for convenience of understanding.

Here, for convenience of explanation, the normal direction of the main surface 11 of the substrate 1, which will be described later, is called the "first direction z". The main scanning direction of the thermal print head A10 is called "second direction x". The sub-scanning direction of the thermal print head A10 is called "third direction y". The first direction z is orthogonal to the second direction x and the third direction y.

In the thermal print head A10, as shown in FIG. 4, the substrate 1 forming the main part of the thermal print head A10 is joined to the heat dissipation member 72. As shown in FIG. Furthermore, the wiring board 71 is positioned next to the board 1 in the third direction y. The wiring board 71 is joined to the heat dissipation member 72 like the board 1 . Formed on the substrate 1 are a plurality of heat generating portions 31 (details of which will be described later) that form part of the resistor layer 3 and are arranged along the second direction x. The plurality of heat generating portions 31 selectively generate heat by the plurality of drive elements 73 mounted on the wiring board 71 . The plurality of drive elements 73 are driven according to print signals externally transmitted via the connector 77 .

Further, the thermal printer B10 according to the present disclosure includes a thermal print head A10 and a platen roller 79, as shown in FIG. In the thermal printer B10, the platen roller 79 is a roller-like mechanism for sending out a recording medium such as thermal paper. When the platen roller 79 presses the recording medium against the plurality of heat generating portions 31, the plurality of heat generating portions 31 perform printing on the recording medium.

As shown in FIG. 1, the substrate 1 has a rectangular shape extending in the second direction x when viewed in the first direction z. Therefore, the second direction x corresponds to the long side direction of the substrate 1 . The third direction y corresponds to the short side direction of the substrate 1 . The substrate 1 comprises semiconductor material. The semiconductor material includes a single crystal material composed of silicon (Si).

As shown in FIG. 5, the substrate 1 includes a first layer 101, a second layer 102 and an intermediate layer 103. As shown in FIG. The second layer 102 is located on the opposite side of the resistor layer 3 with respect to the first layer 101 in the first direction z. The compositions of the first layer 101 and the second layer 102 contain silicon (Si). At least the first layer 101 of the first layer 101 and the second layer 102 contains a single-crystal semiconductor material whose composition is silicon. The intermediate layer 103 is located between the first layer 101 and the second layer 102 in the first direction z. The composition of intermediate layer 103 includes silicon dioxide (SiO ₂ ). Thereby, the thermal conductivity of intermediate layer 103 is lower than the thermal conductivity of each of first layer 101 and second layer 102 . Further, the intermediate layer 103 is electrically insulating, unlike the first layer 101 and the second layer 102 .

As shown in FIG. 5, the substrate 1 has a main surface 11 and a back surface 12 facing opposite to each other in the first direction z. First layer 101 includes major surface 11 . Second layer 102 includes back surface 12 . The plane orientation of the main surface 11 based on the crystal structure of the first layer 101 is (100). As shown in FIG. 4 , in the thermal print head A 10 , the main surface 11 faces the platen roller 79 and the back surface 12 faces the wiring board 71 .

As shown in FIG. 5, the first dimension T1 of the first layer 101 from the main surface 11 to the intermediate layer 103 in the first direction z is different from the second dimension T2 of the second layer 102 in the first direction z. In the thermal printhead A10, the second dimension T2 is larger than the first dimension T1. Furthermore, the dimension t of the intermediate layer 103 in the first direction z is smaller than each of the first dimension T1 and the second dimension T2.

As shown in FIG. 5, the substrate 1 has convex portions 13 . The convex portion 13 is included in the first layer 101 . The convex portion 13 protrudes from the main surface 11 in the first direction z. As shown in FIGS. 1 and 2, the convex portion 13 extends in the second direction x.

As shown in FIGS. 5 and 6 , the convex portion 13 has a top surface 130 , a first inclined surface 131 and a second inclined surface 132 . The top surface 130, the first inclined surface 131 and the second inclined surface 132 extend in the second direction x. The top surface 130 faces the first direction z and is located away from the main surface 11 . The first inclined surface 131 and the second inclined surface 132 are located between the main surface 11 and the top surface 130 . In the thermal printhead A10, the first slanted surface 131 and the second slanted surface 132 are connected to the main surface 11 and the top surface 130, respectively. The first inclined surface 131 and the second inclined surface 132 are positioned apart from each other in the third direction y. The first inclined surface 131 and the second inclined surface 132 are inclined with respect to the main surface 11 . The first slanted surface 131 and the second slanted surface 132 are closer to each other from the main surface 11 toward the top surface 130 . The inclination angle α of each of the first inclined surface 131 and the second inclined surface 132 with respect to the main surface 11 is equal to each other.

The insulating layer 2 covers the main surface 11 and the projections 13 of the substrate 1, as shown in FIGS. The insulating layer 2 is located between the first layer 101 of the substrate 1 and the resistor layer 3 . The substrate 1 is electrically insulated from the resistor layer 3 and the wiring layer 4 by the insulating layer 2 . Insulating layer 2 is made of, for example, silicon dioxide made from tetraethyl orthosilicate (TEOS). An example of the thickness of the insulating layer 2 is 1 μm or more and 15 μm or less. The thermal conductivity of insulating layer 2 is higher than that of intermediate layer 103 of substrate 1 .

The resistor layer 3 is arranged on the main surface 11 and the protrusions 13 of the substrate 1, as shown in FIGS. The resistor layer 3 is in contact with the insulating layer 2 . Thus, the insulating layer 2 is sandwiched between the substrate 1 and the resistor layer 3 in the thermal printhead A10. Resistor layer 3 is made of, for example, tantalum nitride (TaN). An example of the thickness of the resistor layer 3 is 0.02 μm or more and 0.1 μm or less.

As shown in FIGS. 2, 3 and 6, the resistor layer 3 includes multiple heat generating portions 31 . In the resistor layer 3 , the multiple heat generating portions 31 are portions exposed from the wiring layer 4 . By selectively energizing the plurality of heat generating portions 31 from the wiring layer 4, the plurality of heat generating portions 31 locally heat the recording medium. The plurality of heat generating portions 31 are arranged along the second direction x. Among the plurality of heat generating portions 31, two heat generating portions 31 adjacent in the second direction x are positioned apart from each other. A plurality of heat generating portions 31 are formed in contact with the insulating layer 2 . In the thermal print head A10, the plurality of heat generating portions 31 are formed on the top surfaces 130 of the convex portions 13 of the substrate 1. As shown in FIG. The plurality of heat generating portions 31 are positioned at the center of the top surface 130 in the third direction y. As shown in FIG. 4 , in the thermal printer B<b>10 , the multiple heat generating units 31 face the platen roller 79 .

The wiring layer 4 is arranged in contact with the resistor layer 3, as shown in FIGS. The wiring layer 4 is electrically connected to the plurality of heat generating portions 31 of the resistor layer 3 . The electrical resistivity of the wiring layer 4 is lower than that of the resistor layer 3 . Wiring layer 4 is a metal layer made of copper (Cu), for example. An example of the thickness of the wiring layer 4 is 0.3 μm or more and 2.0 μm or less. Alternatively, the wiring layer 4 may be composed of two metal layers, a titanium (Ti) layer laminated on the resistor layer 3 and a copper layer laminated on the titanium layer. An example of the thickness of the titanium layer in this case is 0.1 μm or more and 0.2 μm or less. As shown in FIG. 1 , the wiring layer 4 is positioned away from the periphery of the main surface 11 of the substrate 1 .

As shown in FIG. 1 , the wiring layer 4 includes a common wiring 41 and a plurality of individual wirings 42 . The common wiring 41 is located on the opposite side of the plurality of drive elements 73 with respect to the plurality of heat generating portions 31 of the resistor layer 3 in the third direction y. The plurality of individual wirings 42 are positioned on the opposite side of the common wiring 41 with respect to the plurality of heat generating portions 31 in the third direction y. The common wiring 41 is electrically connected to the plurality of heat generating portions 31 . The plurality of individual wirings 42 are individually connected to the plurality of heat generating portions 31 .

As shown in FIGS. 2 and 3 , the common wiring 41 has a base portion 411 and a plurality of extension portions 412 connected to the base portion 411 . The base portion 411 is located on the opposite side of the plurality of heat generating portions 31 of the resistor layer 3 with respect to the plurality of extension portions 412 in the third direction y. The base 411 has a strip shape extending in the second direction x. The plurality of extending portions 412 are belt-shaped and extend in the third direction y from the end portion of the base portion 411 facing the convex portion 13 of the substrate 1 toward the plurality of heat generating portions 31 . The plurality of extensions 412 are arranged along the second direction x. A portion of each of the plurality of extensions 412 is positioned on the second inclined surface 132 of the projection 13 . In the common wiring 41 , current flows from the base portion 411 to the plurality of heat generating portions 31 via the plurality of extension portions 412 .

As shown in FIGS. 2 and 3 , each of the plurality of individual wirings 42 has a base portion 421 and an extension portion 422 connected to the base portion 421 . The base portion 421 is located on the opposite side of the resistor layer 3 from the plurality of heat generating portions 31 with respect to the extension portion 422 in the third direction y. The bases 421 of each of the plurality of individual wirings 42 form two rows separated from each other in the third direction y. Each of the two columns is arranged along the second direction x. In the row closest to the plurality of heat generating portions 31 among the two rows, the extending portion 422 is positioned between two adjacent base portions 421 .

As shown in FIGS. 2 and 3 , the extending portion 422 has a band shape extending in the third direction y from the end portion of the base portion 421 facing the convex portion 13 of the substrate 1 toward the plurality of heat generating portions 31 . The extending portions 422 of each of the plurality of individual wirings 42 are arranged along the second direction x. A portion of the extending portion 422 of each of the plurality of individual wires 42 is positioned on the first inclined surface 131 of the convex portion 13 . In each of the plurality of individual wirings 42 , current flows from one of the plurality of heat generating portions 31 to the base portion 421 via the extension portion 422 . When viewed in the first direction z, each of the plurality of heat generating portions 31 is sandwiched between one of the extension portions 422 of the plurality of individual wirings 42 and one of the plurality of extension portions 412 of the common wiring 41. . The configuration of the wiring layer 4 and the plurality of heat generating portions 31 shown in FIGS. 2 and 3 is an example. Therefore, the configurations of the wiring layer 4 and the plurality of heat generating portions 31 in the present disclosure are not limited to the configurations shown in FIGS. 2 and 3. FIG.

The protective layer 5 covers a portion of the insulating layer 2, the plurality of heat generating portions 31 of the resistor layer 3, and the wiring layer 4, as shown in FIG. The protective layer 5 has electrical insulation. The composition of the protective layer 5 contains silicon. Protective layer 5 is made of, for example, silicon dioxide or silicon nitride (Si ₃ N ₄ ). Alternatively, the protective layer 5 may be a laminate made of a plurality of these substances. In the thermal printer B10, the platen roller 79 shown in FIG.

As shown in FIG. 5, the protective layer 5 has wiring openings 51 . The wiring opening 51 penetrates the protective layer 5 in the first direction z. From the wiring opening 51, the base portion 421 of each of the plurality of individual wirings 42 and part of the extending portion 422 of each of the plurality of individual wirings 42 are exposed.

The wiring substrate 71 is positioned next to the substrate 1 in the third direction y, as shown in FIG. As shown in FIG. 1, when viewed in the first direction z, the plurality of individual wirings 42 are positioned between the plurality of heat generating portions 31 of the resistor layer 3 and the wiring board 71 in the third direction y. The area of the wiring substrate 71 is larger than the area of the substrate 1 when viewed in the first direction z. Furthermore, when viewed in the first direction z, the wiring board 71 has a rectangular shape with the second direction x as the longitudinal direction. Wiring board 71 is, for example, a PCB board. A plurality of drive elements 73 and connectors 77 are mounted on the wiring board 71 .

The heat dissipation member 72 faces the rear surface 12 of the substrate 1 as shown in FIG. The back surface 12 is joined to the heat dissipation member 72 . The wiring board 71 is joined to the heat dissipation member 72 with a fastening member such as a screw. When the thermal print head A10 is used, part of the heat generated from the plurality of heat generating portions 31 of the resistor layer 3 is conducted to the heat radiating member 72 via the substrate 1. FIG. The heat conducted to the heat radiating member 72 is radiated to the outside. Heat dissipation member 72 is made of, for example, aluminum (Al).

As shown in FIGS. 1 and 4, the plurality of drive elements 73 are mounted on the wiring board 71 via an electrically insulating die bonding material (not shown). The plurality of drive elements 73 are semiconductor elements configured with various circuits. One ends of the plurality of first wires 74 and one ends of the plurality of second wires 75 are conductively joined to the plurality of driving elements 73 . The other ends of the plurality of first wires 74 are individually conductively joined to the bases 421 of the plurality of individual wirings 42 . The other ends of the plurality of second wires 75 are conductively joined to wiring (not shown) provided on the wiring substrate 71 and conducting to the connector 77 .

As described above, electrical signals for printing and electrical signals for controlling the driving elements 73 are input from the outside to the driving elements 73 via the connector 77 . The plurality of drive elements 73 selectively apply voltages to the plurality of individual wirings 42 based on these electrical signals. Furthermore, a constant voltage is applied to the common wiring 41 from the outside through the connector 77 . In this case, a potential difference is generated between the common wiring 41 and any one of the plurality of individual wirings 42 to selectively generate heat in the plurality of heat generating portions 31 of the resistor layer 3 .

The sealing resin 76 covers the plurality of drive elements 73, the plurality of first wires 74, and the plurality of second wires 75, as shown in FIG. Furthermore, the sealing resin 76 covers a portion of each of the insulating layer 2 and the wiring board 71 and a portion of each of the plurality of individual wirings 42 . The sealing resin 76 has electrical insulation. The sealing resin 76 is a black soft synthetic resin used for underfill, for example. Alternatively, the sealing resin 76 may be black and hard synthetic resin.

The connector 77 is attached to one end of the wiring board 71 in the third direction y, as shown in FIGS. The connector 77 is connected to the thermal printer B10. The connector 77 has a plurality of pins (not shown). Some of the plurality of pins are electrically connected to wiring (not shown) to which the plurality of second wires 75 are conductively joined on the wiring board 71 . Further, another part of the plurality of pins is electrically connected to wiring (not shown) that is electrically connected to the base portion 411 of the common wiring 41 on the wiring board 71 . Thereby, a constant voltage is applied to the common wiring 41 from the outside through the connector 77 .

Next, an example of a method for manufacturing the thermal print head A10 will be described with reference to FIGS. 7 to 17. FIG. 7 to 17 are the same as the cross-sectional position of FIG. 5 showing the main part of the thermal print head A10.

First, as shown in FIGS. 7-11, a substrate 81 having a major surface 11 is formed. The substrate 81 is formed by connecting a plurality of regions corresponding to the substrates 1 in the direction orthogonal to the first direction z. The process of forming the base material 81 includes the process of forming the coating layer 813 shown in FIG. 7, the process of bonding the first base material 811 shown in FIG. 8 to the second base material 812, and the process shown in FIGS. A step of forming the mask layer 89 on the first base material 811 and a step of forming the protrusions 13 shown in FIG. 11 on the first base material 811 are included.

First, as shown in FIG. 7, a coating layer 813 is formed to cover at least one of the first surface 81A of the first base material 811 and the second surface 81B of the second base material 812 . Substrate 81 includes a first substrate 811 and a second substrate 812 . The composition of first substrate 811 and second substrate 812 includes silicon. The first base material 811 and the second base material 812 are silicon wafers. Of the first base material 811 and the second base material 812, at least the first base material 811 contains a single crystal material composed of silicon. The first base material 811 has a first surface 81A and a third surface 81C facing opposite to each other in the first direction z. The plane orientations of the first surface 81A and the third surface 81C based on the crystal structure of the first base material 811 are both (100 plane). The second base material 812 has a second surface 81B and a fourth surface 81D facing opposite to each other in the first direction z. The second surface 81B faces the first surface 81A. In manufacturing the thermal print head A10, the coating layer 813 is formed to cover the second surface 81B and the fourth surface 81D. Therefore, the coating layer 813 covers only the surface of the second base material 812 . The coating layer 813 is formed by a thermal oxidation method.

Next, as shown in FIG. 8, the first base material 811 is attached to the second base material 812 with the coating layer 813 interposed therebetween. In this step, first, the first base material 811 and the second base material 812 covered with the coating layer 813 are washed. For cleaning, a cleaning liquid to which ultrasonic vibration is applied is used. The cleaning liquid is pure water, for example. The frequency of the ultrasonic waves is in the megahertz band. After that, after bringing the first surface 81A of the first base material 811 into contact with the coating layer 813, impact is applied to the third surface 81C of the first base material 811 using a pin. Thereby, the crystals on the first surface 81A and the crystals on the surface of the coating layer 813 are bonded. As described above, the substrate 81 in which the first substrate 811 and the second substrate 812 are integrated with the coating layer 813 interposed therebetween is obtained. Through this step, the coating layer 813 becomes one element of the base material 81 .

Next, as shown in FIGS. 9 and 10, a mask layer 89 is formed on the first base material 811 . In forming the mask layer 89, first, as shown in FIG. 9, the mask layer 89 covering the entire third surface 81C of the base material 81 is formed by plasma CVD (Chemical Vapor Deposition). Mask layer 89 is either a thin film of silicon nitride or a thin film of silicon dioxide. Thereafter, as shown in FIG. 11, the mask layer 89 covering the entire third surface 81C is partially removed by lithography patterning and reactive ion etching (RIE). Thus, the formation of the mask layer 89 is completed. Mask layer 89 has covering portion 891 and opening 892 . The covering portion 891 covers the third surface 81C. The third surface 81C is exposed through the opening 892 .

Next, as shown in FIG. 11, the main surface 11 and the projections 13 are formed on the first base material 811 by anisotropic etching, and then the mask layer 89 is removed. The main surface 11 faces the same direction as the third surface 81C of the first substrate 811 in the first direction z, and is located between the third surface 81C and the coating layer 813 . The convex portion 13 protrudes from the main surface 11 in the first direction z and extends in the second direction x. The principal surface 11 and the projections 13 are formed by anisotropically etching the third surface 81C exposed from the openings 892 of the mask layer 89, thereby forming the principal surface 11 and the projections 13 on the first base material 811. be done. An etchant used for anisotropic etching is, for example, a potassium hydroxide (KOH) aqueous solution. After that, the mask layer 89 and the portion of the coating layer 813 covering the fourth surface 81D of the second base material 812 are removed by wet etching using hydrofluoric acid. As described above, the base material 81 having the main surface 11 is obtained, and the projections 13 are formed on the first base material 811 . Furthermore, the fourth surface 81</b>D becomes the back surface 12 of the substrate 1 . The region of the third surface 81</b>C covered with the covering portion 891 of the mask layer 89 becomes the top surface 130 of the convex portion 13 . Since the convex portion 13 is formed by anisotropic etching, the inclination angles α of the first inclined surface 131 and the second inclined surface 132 of the convex portion 13 with respect to the main surface 11 are equal to each other.

Next, as shown in FIG. 12, insulating layer 2 is formed to cover main surface 11 and projections 13 of base material 81 . The insulating layer 2 is formed by laminating a plurality of thin films of silicon dioxide formed by plasma CVD using tetraethyl orthosilicate (TEOS) as a raw material gas.

Next, as shown in FIGS. 13 to 15, resistor layer 3 and wiring layer 4 are formed. The resistor layer 3 includes a plurality of heat generating portions 31 arranged along the second direction x. The wiring layer 4 is electrically connected to the plurality of heat generating portions 31 . Furthermore, the step of forming the wiring layer 4 includes a step of forming a common wiring 41 and a plurality of individual wirings 42 . In the base material 81, the common wiring 41 is positioned on one side in the third direction y with respect to the plurality of heat generating portions 31 of the resistor layer 3 shown in FIG. In the base material 81, the plurality of individual wirings 42 are positioned on the opposite side of the common wiring 41 with respect to the plurality of heat generating portions 31 shown in FIG. 17 in the third direction y.

First, as shown in FIG. 13 , a resistor film 82 is formed on the main surface 11 and the projections 13 of the base material 81 . Resistor film 82 is formed to cover the entire surface of insulating layer 2 . The resistor film 82 is formed by stacking a thin film of tantalum nitride on the insulating layer 2 by sputtering.

Next, as shown in FIG. 14, a conductive layer 83 covering the entire surface of the resistor film 82 is formed. The conductive layer 83 is formed by laminating a copper thin film on the resistor film 82 a plurality of times by sputtering. In addition, in the formation of the conductive layer 83, a thin film of titanium is laminated on the resistor film 82 by sputtering, and then a thin film of copper is laminated a plurality of times on the titanium thin film by sputtering. may

Next, as shown in FIG. 15, the conductive layer 83 is subjected to lithographic patterning, and then part of the conductive layer 83 is removed. The removal is performed by wet etching using a mixed solution of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ). Thereby, the common wiring 41 and the plurality of individual wirings 42 are formed in contact with the resistor film 82 . At the same time, the region of the resistor film 82 formed on the top surface 130 of the protrusion 13 of the base material 81 is exposed from the wiring layer 4 . Thereafter, after lithographic patterning is applied to the resistor film 82 and the wiring layer 4, a portion of the resistor film 82 is removed. The removal is performed by reactive ion etching. Thereby, the resistor layer 3 is formed on the main surface 11 and the protrusions 13 of the base material 81 . A plurality of heat generating portions 31 appear on the top surface 130 of the base material 81 .

Next, as shown in FIG. 16, a protective layer 5 is formed to cover a portion of the insulating layer 2, the plurality of heat generating portions 31 of the resistor layer 3, and the wiring layer 4. Next, as shown in FIG. The protective layer 5 is formed by laminating a plurality of silicon nitride thin films by plasma CVD. In addition, the protective layer 5 can also be formed by laminating a plurality of silicon dioxide thin films by a sputtering method.

Next, as shown in FIG. 17, wiring openings 51 are formed through the protective layer 5 in the first direction z. The wiring opening 51 is formed by removing a portion of the protective layer 5 after performing lithographic patterning on the protective layer 5 . The removal is performed by reactive ion etching. Thereby, a part of each of the plurality of individual wires 42 is exposed from the wire opening 51 . The part of each of the plurality of individual wirings 42 exposed from the wiring opening 51 includes the base portion 421 of each of the plurality of individual wirings 42 shown in FIG. 5 and the extending portion of each of the plurality of individual wirings 42 shown in FIG. 422. A metal layer such as gold may be laminated on a part of each of the plurality of individual wires 42 exposed from the wire opening 51 by plating.

Next, the base material 81 is cut in the thickness direction along the second direction x and the third direction y. The individual piece thus obtained becomes the main part of the thermal print head A10 including the substrate 1. FIG. A dicing saw is an example of a cutting device for the base material 81 . The cutting line of the base material 81 is set at a position away from the projections 13 of the base material 81 . This prevents the blade of the cutting device from coming into contact with the protrusion 13 . Through this process, the first base material 811 becomes the first layer 101 of the substrate 1 . The second base material 812 becomes the second layer 102 of the substrate 1 . The covering layer 813 becomes the intermediate layer 103 of the substrate 1 .

Next, a plurality of drive elements 73 are mounted on the wiring board 71 . Next, the rear surface 12 of the substrate 1 and the wiring board 71 are joined to the heat dissipation member 72 . Next, the plurality of first wires 74 and the plurality of second wires 75 are conductively joined to the wiring board 71 , the plurality of driving elements 73 , and the bases 421 of the plurality of individual wirings 42 . Finally, a sealing resin 76 covering the plurality of drive elements 73, the plurality of first wires 74, and the plurality of second wires 75 is formed. Finally, the connector 77 is attached to the wiring board 71 . The thermal print head A10 is obtained through the above steps.

Next, the effects of the thermal print head A10 will be described.

The thermal printhead A10 comprises a substrate 1 comprising a first layer 101, a second layer 102 and an intermediate layer 103. As shown in FIG. First layer 101 includes major surface 11 . A resistor layer 3 is arranged on the main surface 11 . The second layer 102 is located on the opposite side of the resistor layer 3 with respect to the first layer 101 in the first direction z. Intermediate layer 103 is located between first layer 101 and second layer 102 . The thermal conductivity of intermediate layer 103 is lower than the thermal conductivity of each of first layer 101 and second layer 102 . By adopting this configuration, the heat conducted from the resistor layer 3 to the first layer 101 is less likely to be conducted immediately to the second layer 102 by the intermediate layer 103 . As a result, heat is not immediately released from the first layer 101, so the heat storage performance of the substrate 1 is improved. Therefore, according to the thermal print head A10, by improving the heat storage performance of the substrate 1, it is possible to suppress a decrease in printing efficiency.

A first dimension T1 of the first layer 101 from the main surface 11 to the intermediate layer 103 in the first direction z is different from a second dimension T2 of the second layer 102 in the first direction z. By adopting this configuration, the heat storage performance of the first layer 101 can be freely adjusted. For example, if the first dimension T1 is made smaller than the second dimension T2, the thermal resistance of the first layer 101 in the first direction z increases, so the heat storage performance of the first layer 101 can be further improved.

In the case described above, the second dimension T2 of the second layer 102 is greater than the first dimension T1 of the first layer 101 . By adopting this configuration, it is possible to prevent bending failure of the substrate 1 even when the first dimension T1 is set as small as possible. Here, since at least the first layer 101 must contain a single-crystal semiconductor material in order for the substrate 1 to have the projections 13, the substrate 1 becomes more dense as the first dimension T1 increases. Cost increases. Therefore, the cost of the substrate 1 can be reduced by setting the first dimension T1 as small as possible.

A dimension t of the intermediate layer 103 in the first direction z is smaller than each of the first dimension T1 of the first layer 101 and the second dimension T2 of the second layer 102 . By adopting this configuration, the thermal resistance of the intermediate layer 103 in the first direction z increases, so the heat storage performance of the first layer 101 can be further improved.

The substrate 1 has a convex portion 13 that protrudes from the main surface 11 in the first direction z. A plurality of heat generating portions 31 of the resistor layer 3 are formed on the convex portion 13 . By adopting this configuration, when printing on the recording medium shown in FIG. 4, the contact area of the recording medium with the thermal print head A10 is minimized, and heat from the plurality of heat generating portions 31 is transferred to the recording medium. can be done. As a result, it is possible to improve the print quality on the recording medium.

The thermal print head A10 further includes an insulating layer 2 covering the main surface 11 and the protrusions 13 of the substrate 1. As shown in FIG. The insulating layer 2 is located between the first layer 101 and the resistor layer 3 . By adopting this configuration, it is possible to achieve electrical insulation between the substrate 1 and the resistor layer 3 and the wiring layer 4 even if the first layer 101 contains a semiconductor material. Furthermore, the thermal conductivity of insulating layer 2 is higher than that of intermediate layer 103 . By adopting this configuration, heat from the plurality of heat generating portions 31 can be rapidly conducted to the first layer 101 .

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

The thermal printhead A10 further includes a heat dissipation member 72. As shown in FIG. A rear surface 12 of the substrate 1 is joined to a heat dissipation member 72 . By adopting this configuration, the heat conducted from the intermediate layer 103 to the second layer 102 is quickly released to the outside through the heat dissipation member 72 . As a result, excessive improvement in the heat storage performance of the substrate 1 can be suppressed.

[Second embodiment]
A thermal print head A20 according to a second embodiment of the present disclosure will be described based on FIGS. 18 and 19. FIG. In these figures, the same or similar elements as those of the thermal print head A10 described above are denoted by the same reference numerals, and overlapping descriptions are omitted. Here, the cross-sectional position of FIG. 18 is the same as the cross-sectional position of FIG. 5 showing the main part of the thermal print head A10.

In the thermal printhead A20, the configuration of the intermediate layer 103 of the substrate 1 is different from that of the thermal printhead A10.

As shown in FIGS. 18 and 19, intermediate layer 103 includes first intermediate layer 103A and second intermediate layer 103B laminated on first intermediate layer 103A. The first intermediate layer 103A is in contact with the first layer 101 of the substrate 1 . The second intermediate layer 103B is in contact with the second layer 102 of the substrate 1 . The dimension of the second intermediate layer 103B in the first direction z is substantially equal to the dimension of the first intermediate layer 103A in the first direction z.

Next, an example of a method for manufacturing the thermal print head A20 will be described with reference to FIGS. 20 and 21. FIG. Here, the cross-sectional positions of FIGS. 20 and 21 are the same as the cross-sectional position of FIG. 18 showing the main part of the thermal print head A20.

First, as shown in FIG. 20, a coating layer 813 is formed to cover at least one of the first surface 81A of the first base material 811 and the second surface 81B of the second base material 812 . In the manufacture of thermal printhead A20, coating layers 813 include a first coating layer 813A and a second coating layer 813B. The first covering layer 813A covers the first surface 81A and the third surface 81C of the first base material 811 . The second coating layer 813B covers the second surface 81B and the fourth surface 81D of the first base material 811 . The first base material 811 and the second base material 812 are formed by thermal oxidation.

Next, as shown in FIG. 21, the first base material 811 is attached to the second base material 812 with the coating layer 813 interposed therebetween. In this configuration, the first base material 811 covered with the first coating layer 813A and the second base material 812 covered with the second coating layer 813B are cleaned by the same method as in the manufacture of the thermal print head A10. After the first coating layer 813A is brought into contact with the second coating layer 813B in the first direction z, the portion of the first coating layer 813A covering the third surface 81C of the first substrate 811 is impacted using a pin. As a result, the crystals of the first covering layer 813A and the crystals of the second covering layer 813B are bonded at the interface between the first covering layer 813A and the second covering layer 813B. Finally, the entire portion of the first covering layer 813A covering the third surface 81C is removed by reactive ion etching. As described above, the substrate 81 in which the first substrate 811 and the second substrate 812 are integrated with the first coating layer 813A and the second coating layer 813B interposed therebetween is obtained. The subsequent steps are the same as those for manufacturing the thermal print head A10. Therefore, the description of the method of manufacturing the thermal print head A20 in the steps after the step of forming the mask layer 89 on the first substrate 811 (see FIGS. 9 and 10) will be omitted.

Next, the effects of the thermal print head A20 will be described.

The thermal printhead A20 comprises a substrate 1 comprising a first layer 101, a second layer 102 and an intermediate layer 103. FIG. First layer 101 includes major surface 11 . A resistor layer 3 is arranged on the main surface 11 . The second layer 102 is located on the opposite side of the resistor layer 3 with respect to the first layer 101 in the first direction z. Intermediate layer 103 is located between first layer 101 and second layer 102 . The thermal conductivity of intermediate layer 103 is lower than the thermal conductivity of each of first layer 101 and second layer 102 . Therefore, by improving the heat storage performance of the substrate 1 also with the thermal print head A20, it is possible to suppress the deterioration of the printing efficiency. Further, the thermal print head A20 has the same configuration as the thermal print head A10, and thus has the same effect as the thermal print head A10.

In the thermal printhead A20, the intermediate layer 103 includes a first intermediate layer 103A and a second intermediate layer 103B laminated on the first intermediate layer 103A. By adopting this configuration, the dimension t of the intermediate layer 103 in the first direction z can be set larger. This makes it possible to further improve the heat storage performance of the first layer 101 .

[Third embodiment]
A thermal print head A30 according to the third embodiment of the present disclosure will be described based on FIG. In these figures, the same or similar elements as those of the thermal print head A10 described above are denoted by the same reference numerals, and overlapping descriptions are omitted. Here, the cross-sectional position of FIG. 22 is the same as the cross-sectional position of FIG. 5 showing the main part of the thermal print head A10.

In the thermal print head A30, the configuration of the substrate 1 is different from that of the thermal print head A10.

As shown in FIG. 22, substrate 1 further includes an outer layer 104 . The outer layer 104 is located on the opposite side of the intermediate layer 103 with respect to the second layer 102 in the first direction z. Outer layer 104 includes back surface 12 . The composition of outer layer 104 includes silicon dioxide. Thereby, the thermal conductivity of the outer layer 104 is lower than the thermal conductivity of each of the first layer 101 and the second layer 102 . The dimension t2 of the outer layer 104 in the first direction z is approximately equal to the dimension t1 of the intermediate layer 103 in the first direction z (equivalent to dimension t in the thermal printhead A10).

Next, an example of a method for manufacturing the thermal print head A30 will be described with reference to FIG. Here, the cross-sectional position of FIG. 23 is the same as the cross-sectional position of FIG. 22 showing the main part of the thermal print head A30.

FIG. 23 shows a state after main surface 11 and projections 13 are formed on first base material 811 of base material 81 by anisotropic etching. The steps up to forming the main surface 11 and the projections 13 on the first base material 811 are the same as the steps for manufacturing the thermal print head A10. After forming main surface 11 and projections 13, mask layer 89 is removed by reactive ion etching. At this time, the portion of the coating layer 813 covering the fourth surface 81D of the second base material 812 is not removed. As a result, the relevant portion becomes the outer layer 104 of the substrate 1 . The subsequent steps are the same as those for manufacturing the thermal print head A10. Therefore, the description of the method of manufacturing the thermal print head A30 in the steps after the step of forming the insulating layer 2 (see FIG. 12) is omitted.

Next, the effects of the thermal print head A30 will be described.

The thermal printhead A30 comprises a substrate 1 comprising a first layer 101, a second layer 102 and an intermediate layer 103. FIG. First layer 101 includes major surface 11 . A resistor layer 3 is arranged on the main surface 11 . The second layer 102 is located on the opposite side of the resistor layer 3 with respect to the first layer 101 in the first direction z. Intermediate layer 103 is located between first layer 101 and second layer 102 . The thermal conductivity of intermediate layer 103 is lower than the thermal conductivity of each of first layer 101 and second layer 102 . Therefore, by improving the heat storage performance of the substrate 1 also with the thermal print head A30, it is possible to suppress the deterioration of the printing efficiency. Further, the thermal print head A30 has the same configuration as the thermal print head A10, and thus has the same effect as the thermal print head A10.

In thermal printhead A30 the substrate 1 further comprises an outer layer 104 . The outer layer 104 is located on the opposite side of the intermediate layer 103 with respect to the second layer 102 in the first direction z. The thermal conductivity of outer layer 104 is lower than the thermal conductivity of each of first layer 101 and second layer 102 . By adopting this configuration, the heat conducted from the intermediate layer 103 to the second layer 102 is not released immediately to the outside, so that the heat storage performance of the second layer 102 as well as the first layer 101 can be improved.

[Fourth embodiment]
A thermal print head A40 according to the fourth embodiment of the present disclosure will be described based on FIGS. 24 and 25. FIG. In these figures, the same or similar elements as those of the thermal print head A10 described above are denoted by the same reference numerals, and overlapping descriptions are omitted. Here, the cross-sectional position of FIG. 24 is the same as the cross-sectional position of FIG. 5 showing the main part of the thermal print head A10.

In the thermal print head A40, the configuration of the protrusions 13 of the substrate 1 and the configuration of the plurality of heat generating portions 31 of the resistor layer 3 are different from those of the thermal print head A10.

As shown in FIGS. 24 and 25 , the convex portion 13 has a third inclined surface 133 and a fourth inclined surface 134 . The third inclined surface 133 and the fourth inclined surface 134 are connected to the top surface 130 of the protrusion 13 and are inclined with respect to the main surface 11 and the top surface 130 of the substrate 1 . The third inclined surface 133 is located on the side where the first inclined surface 131 is located with respect to the top surface 130 in the third direction y. The fourth inclined surface 134 is located on the opposite side of the third inclined surface 133 with respect to the top surface 130 in the third direction y. The third slanted surface 133 and the fourth slanted surface 134 approach each other from the main surface 11 toward the top surface 130 .

As shown in FIG. 25, the inclination angles γ of each of the third inclined surface 133 and the fourth inclined surface 134 with respect to the main surface 11 are equal to each other. The inclination angle γ of the third inclined surface 133 is smaller than the inclination angle α of the first inclined surface 131 with respect to the main surface 11 . The inclination angle γ of the fourth inclined surface 134 is smaller than the inclination angle α of the second inclined surface 132 with respect to the main surface 11 . The third inclined surface 133 and the fourth inclined surface 134 can be formed by performing the following process between the process shown in FIG. 11 and the process shown in FIG. 12 for manufacturing the thermal print head A10. In this step, the boundary between the top surface 130 and the first inclined surface 131 and the boundary between the top surface 130 and the second inclined surface 132 are subjected to wet etching using a tetramethylammonium hydroxide (TMAH) aqueous solution. is.

As shown in FIG. 25, the plurality of heat generating portions 31 of the resistor layer 3 are formed on the top surface 130, the fourth inclined surface 134 and the second inclined surface 132 of the convex portion 13. As shown in FIG. Alternatively, the plurality of heat generating portions 31 may be configured to be formed on the top surface 130 , the third inclined surface 133 and the first inclined surface 131 of the convex portion 13 .

Next, the effects of the thermal print head A40 will be described.

The thermal printhead A40 comprises a substrate 1 comprising a first layer 101, a second layer 102 and an intermediate layer 103. FIG. First layer 101 includes major surface 11 . A resistor layer 3 is arranged on the main surface 11 . The second layer 102 is located on the opposite side of the resistor layer 3 with respect to the first layer 101 in the first direction z. Intermediate layer 103 is located between first layer 101 and second layer 102 . The thermal conductivity of intermediate layer 103 is lower than the thermal conductivity of each of first layer 101 and second layer 102 . Therefore, even with the thermal print head A40, by improving the heat storage performance of the substrate 1, it is possible to suppress a decrease in printing efficiency. Further, the thermal print head A40 has the same configuration as the thermal print head A10, and thus has the same effect as the thermal print head A10.

In the thermal print head A40, the convex portion 13 has a third inclined surface 133 and a fourth inclined surface 134. As shown in FIG. The third inclined surface 133 and the fourth inclined surface 134 are connected to the top surface 130 of the protrusion 13 and are inclined with respect to the main surface 11 and the top surface 130 of the substrate 1 . The inclination angle γ of the third inclined surface 133 is smaller than the inclination angle α of the first inclined surface 131 with respect to the main surface 11 . The inclination angle γ of the fourth inclined surface 134 is smaller than the inclination angle α of the second inclined surface 132 with respect to the main surface 11 . By adopting this configuration, the shape of the part of the wiring layer 4 formed along the convex portion 13 becomes smoother. At the same time, in the wiring layer 4 formed along the convex portion 13, the occurrence of defects, disconnections, etc. in the wiring pattern is suppressed.

The present disclosure is not limited to the embodiments described above. The specific configuration of each part of the present disclosure can be modified in various ways.

The technical configuration of the thermal printhead and the manufacturing method thereof provided by the present disclosure will be added below.
[Appendix 1]
a substrate having a main surface facing in a first direction;
a resistor layer including a plurality of heat generating portions arranged along a second direction orthogonal to the first direction and arranged on the main surface;
a wiring layer that is electrically connected to the plurality of heat generating parts and arranged in contact with the resistor layer;
The substrate includes a first layer including the main surface, a second layer located on the opposite side of the resistor layer with respect to the first layer in the first direction, and the first layer and the second layer. an intermediate layer positioned between the layers;
The thermal printhead, wherein the thermal conductivity of the intermediate layer is lower than the thermal conductivity of each of the first layer and the second layer.
[Appendix 2]
2. The thermal printhead of Claim 1, wherein a first dimension of said first layer from said major surface to said intermediate layer in said first direction is different than a second dimension of said second layer in said first direction.
[Appendix 3]
3. The thermal printhead of Claim 2, wherein the second dimension is greater than the first dimension.
[Appendix 4]
4. The thermal printhead of Claim 2 or 3, wherein the dimension of the intermediate layer in the first direction is smaller than each of the first dimension and the second dimension.
[Appendix 5]
the substrate further includes an outer layer located on the opposite side of the intermediate layer with respect to the second layer in the first direction;
5. The thermal printhead according to any one of Appendices 1 to 4, wherein the thermal conductivity of the outer layer is lower than the thermal conductivity of each of the first layer and the second layer.
[Appendix 6]
6. The thermal printhead of any of Clauses 1-5, wherein the composition of the first layer and the second layer comprises silicon.
[Appendix 7]
7. The thermal printhead of Claim 6, wherein the composition of the intermediate layer comprises silicon dioxide.
[Appendix 8]
the substrate has a protrusion projecting from the main surface and extending in the second direction;
The plurality of heat generating parts are positioned on the convex part,
The convex portion has a top surface, a first inclined surface and a second inclined surface,
The top surface faces the first direction and is located away from the main surface,
The first inclined surface and the second inclined surface are located between the main surface and the top surface and are inclined with respect to the main surface,
the first inclined surface and the second inclined surface are positioned apart from each other in a third direction orthogonal to the first direction and the second direction;
8. The thermal printhead according to appendix 6 or 7, wherein the first inclined surface and the second inclined surface approach each other from the main surface toward the top surface.
[Appendix 9]
The convex portion has a third inclined surface located on the same side as the first inclined surface with respect to the top surface in the third direction and inclined with respect to the main surface,
The third inclined surface is located between the first inclined surface and the top surface,
8. The thermal printhead according to appendix 8, wherein the inclination angle of the third inclined surface with respect to the main surface is smaller than the inclination angle of the first inclined surface with respect to the main surface.
[Appendix 10]
the convex portion has a fourth inclined surface positioned opposite to the third inclined surface with respect to the top surface in the third direction and inclined with respect to the main surface;
The fourth inclined surface is located between the second inclined surface and the top surface,
10. The thermal printhead according to appendix 9, wherein the inclination angle of the fourth inclined surface with respect to the main surface is smaller than the inclination angle of the second inclined surface with respect to the main surface.
[Appendix 11]
further comprising an insulating layer covering the main surface and the convex portion;
11. The thermal printhead according to any one of Appendixes 8 to 10, wherein the insulating layer is located between the first layer and the resistor layer.
[Appendix 12]
12. The thermal printhead according to appendix 11, wherein the thermal conductivity of the insulating layer is higher than the thermal conductivity of the intermediate layer.
[Appendix 13]
13. The thermal printhead according to any one of Appendices 1 to 12, further comprising a protective layer covering the plurality of heat generating portions and the wiring layer.
[Appendix 14]
The wiring layer includes a common wiring and a plurality of individual wirings,
The common wiring is electrically connected to the plurality of heat generating parts,
14. The thermal printhead according to any one of Appendices 1 to 13, wherein the plurality of individual wirings are individually connected to the plurality of heat generating portions.
[Appendix 15]
further comprising a heat dissipating member,
the substrate has a back surface facing away from the main surface in the first direction;
15. The thermal printhead according to any one of appendices 1 to 14, wherein the back surface is bonded to the heat dissipation member.
[Appendix 16]
forming a substrate having a major surface facing in a first direction;
forming, on the main surface, a resistor layer including a plurality of heat generating portions arranged along a second direction orthogonal to the first direction;
a step of forming a wiring layer electrically connected to the plurality of heat generating portions in contact with the resistor layer;
The base material includes a first base material including the main surface and having a first surface facing in the first direction opposite to the main surface, and a second surface facing the first surface. 2 substrates;
The step of forming the substrate comprises: forming a coating layer covering at least one of the first surface and the second surface; and a step of attaching to the material,
A method of manufacturing a thermal printhead, wherein the thermal conductivity of the coating layer is lower than the thermal conductivity of each of the first substrate and the second substrate.
[Appendix 17]
the compositions of the first substrate and the second substrate comprise silicon;
17. The method of manufacturing a thermal printhead according to appendix 16, wherein the coating layer is formed by a thermal oxidation method.
[Appendix 18]
The step of forming the base material includes, after the step of bonding the first base material to the second base material, forming, on the first base material, protrusions that protrude from the main surface and extend in the second direction. 18. A method of manufacturing a thermal printhead according to Appendix 17, comprising the step of:

A10, A20, A30, A40: thermal print head B10: thermal printer 1: substrate 101: first layer 102: second layer 103: intermediate layer 103A: first intermediate layer 103B: second intermediate layer 104: outer layer 11: Main surface 12: Back surface 13: Convex part 130: Top surface 131: First inclined surface 132: Second inclined surface 133: Third inclined surface 134: Fourth inclined surface 2: Insulating layer 3: Resistor layer 31: Heat generating part 4: Wiring layer 41: Common wiring 411: Base 412: Extension 42: Individual wiring 421: Base 422: Extension 5: Protective layer 51: Wiring opening 71: Wiring substrate 72: Heat dissipation member 73: Driving element 74: First wire 75: Second wire 76: Sealing resin 77: Connector 79: Platen roller 81: Base material 811: First base material 812: Second base material 813: Coating layer 813A: First coating layer 813B: Second Covering layer 81A: first surface 81B: second surface 81C: third surface 81D: fourth surface 82: resistor film 83: conductive layer 89: mask layer 891: covering portion 892: opening z: first direction x: Second direction y: Third direction

Claims (18)

a substrate having a main surface facing in a first direction;
a resistor layer including a plurality of heat generating portions arranged along a second direction orthogonal to the first direction and arranged on the main surface;
a wiring layer that is electrically connected to the plurality of heat generating parts and arranged in contact with the resistor layer;
The substrate includes a first layer including the main surface, a second layer located on the opposite side of the resistor layer with respect to the first layer in the first direction, and the first layer and the second layer. an intermediate layer positioned between the layers;
The thermal printhead, wherein the thermal conductivity of the intermediate layer is lower than the thermal conductivity of each of the first layer and the second layer. 2. The thermal printhead of claim 1, wherein a first dimension of said first layer from said major surface to said intermediate layer in said first direction is different than a second dimension of said second layer in said first direction. 3. The thermal printhead of claim 2, wherein said second dimension is greater than said first dimension. 4. A thermal printhead according to claim 2 or 3, wherein the dimension of said intermediate layer in said first direction is smaller than each of said first dimension and said second dimension. the substrate further includes an outer layer located on the opposite side of the intermediate layer with respect to the second layer in the first direction;
5. A thermal printhead according to any one of claims 1 to 4, wherein the thermal conductivity of said outer layer is lower than the thermal conductivity of each of said first layer and said second layer. 6. The thermal printhead of any of claims 1-5, wherein the composition of the first layer and the second layer comprises silicon. 7. The thermal printhead of claim 6, wherein the intermediate layer composition comprises silicon dioxide. the substrate has a protrusion projecting from the main surface and extending in the second direction;
The plurality of heat generating parts are positioned on the convex part,
The convex portion has a top surface, a first inclined surface and a second inclined surface,
The top surface faces the first direction and is located away from the main surface,
The first inclined surface and the second inclined surface are located between the main surface and the top surface and are inclined with respect to the main surface,
the first inclined surface and the second inclined surface are positioned apart from each other in a third direction orthogonal to the first direction and the second direction;
8. A thermal printhead according to claim 6, wherein said first inclined surface and said second inclined surface approach each other from said main surface toward said top surface. The convex portion has a third inclined surface located on the same side as the first inclined surface with respect to the top surface in the third direction and inclined with respect to the main surface,
The third inclined surface is located between the first inclined surface and the top surface,
9. A thermal printhead according to claim 8, wherein the inclination angle of said third inclined surface with respect to said main surface is smaller than the inclination angle of said first inclined surface with respect to said main surface. the convex portion has a fourth inclined surface positioned opposite to the third inclined surface with respect to the top surface in the third direction and inclined with respect to the main surface;
The fourth inclined surface is located between the second inclined surface and the top surface,
10. The thermal printhead according to claim 9, wherein an inclination angle of said fourth inclined surface with respect to said main surface is smaller than an inclination angle of said second inclined surface with respect to said main surface. further comprising an insulating layer covering the main surface and the convex portion;
11. A thermal printhead according to any one of claims 8 to 10, wherein said insulating layer is located between said first layer and said resistor layer. 12. The thermal printhead of claim 11, wherein the insulating layer has a higher thermal conductivity than the intermediate layer. 13. The thermal printhead according to any one of claims 1 to 12, further comprising a protective layer covering said plurality of heat generating portions and said wiring layer. The wiring layer includes a common wiring and a plurality of individual wirings,
The common wiring is electrically connected to the plurality of heat generating parts,
14. The thermal printhead according to any one of claims 1 to 13, wherein said plurality of individual wirings are individually connected to said plurality of heat generating portions. further comprising a heat dissipating member,
the substrate has a back surface facing away from the main surface in the first direction;
15. The thermal printhead according to any one of claims 1 to 14, wherein said back surface is joined to said heat radiating member. forming a substrate having a major surface facing in a first direction;
forming, on the main surface, a resistor layer including a plurality of heat generating portions arranged along a second direction orthogonal to the first direction;
a step of forming a wiring layer electrically connected to the plurality of heat generating portions in contact with the resistor layer;
The base material includes a first base material including the main surface and having a first surface facing in the first direction opposite to the main surface, and a second surface facing the first surface. 2 substrates;
The step of forming the substrate comprises: forming a coating layer covering at least one of the first surface and the second surface; and a step of attaching to the material,
A method of manufacturing a thermal printhead, wherein the thermal conductivity of the coating layer is lower than the thermal conductivity of each of the first substrate and the second substrate. the compositions of the first substrate and the second substrate comprise silicon;
17. The method of manufacturing a thermal printhead according to claim 16, wherein the coating layer is formed by a thermal oxidation method. The step of forming the base material includes, after the step of bonding the first base material to the second base material, forming, on the first base material, projections that protrude from the main surface and extend in the second direction. 18. A method of manufacturing a thermal printhead according to claim 17, comprising the step of:

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