JPH04319445A - Thermal head and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide the structure and manufacture of a thermal head, which realizes the heating resistor section of a thin-film having excellent coverage and no dispersion of a resistance value while having superior thermal conduction efficiency and can prevent functional deterioration such as electrocorrosion, from which high reliability is obtained, a manufacturing process of which is more simplified and cost of which can be reduced. CONSTITUTION:Opposed first and second electrode sections 24, 25, in which a first conductive layer 22 as a thick-film is used as a base and opposed positions are formed in two layer structure by a second conductive layer 23 as the thick-film, are formed onto a substrate 21, the periphery of the second conductive layer 23 is buried with an insulting stepped burying section 26 and the upper section of the substrate 21 is formed in a projecting structure close to flatness, a resistor layer 27 as a thin-film is formed onto the projecting structure, and a heating resistor section 29 is formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure and manufacturing method of a thermal head installed in, for example, a facsimile machine or a printer.

0002

[Prior Art] This type of thermal head converts electrical recording signals into corresponding heat patterns, and these heat patterns are printed on thermal recording paper or transfer film (for example, an ink ribbon) that develops color by heat. It is used to record pixels by transmitting them to the .

Conventionally, there are two types of thermal heads, for example, a thick film type and a thin film type, and the configurations of each type are shown in FIGS. 3 and 4.

FIGS. 3(a) and 3(b) are partial configuration diagrams of a conventional thick-film thermal head, and FIG. 3(a) is a plan view;
Figure (b) is a sectional view taken along line A--A in figure (a). Figure 4
(a) and (b) are partial configuration diagrams of a conventional thin-film thermal head, where (a) is a plan view and (b) is a cross-sectional view taken along the line B-B in (a). be.

The thick film type thermal head shown in FIG. 3 has electrode parts 2 and 3 made of thick films of Au electrodes, for example, which are formed facing each other on an insulating substrate 1. A resistor layer 4 made of, for example, a Ru2O resistor thick film is formed on the substrate 1 including the opposing regions of the electrode parts 2 and 3 by a thick film forming technique such as a printing method. The portion above the opposing regions 2 and 3 serves as the heat generating resistor portion 5. Further, on the substrate 1 including the resistor layer 4, for example, a resistor protection layer and a
A protective layer 6 for preventing wear and the like is applied. Therefore, the portion from the heat generating resistor section 5 to the protective layer 6 above it serves as a heat generating section 7 that transfers heat to thermal recording paper, an ink ribbon, or the like.

[0006] This thick film type thermal head has a structure in which a plurality of electrode parts 2 and 3 and a heating resistor part 5, ie, a heating element part 7 are arranged as shown in FIG.

When printing using the thick-film thermal head configured as described above, each heat generating resistor section 5 is selectively energized, and the heat generated in the selected heat generating resistor section 5 is Characters, numbers, symbols, images, etc. can be printed on the heat-sensitive recording paper or plain paper by transmitting the heat to the heat-sensitive recording paper, ink ribbon, etc. in contact with the heating element section 7.

The thin film type thermal head shown in FIG. 4 has an insulating substrate 11, and on the substrate 11, for example, a vacuum film forming technique such as sputtering or vapor deposition is used for film formation, and a photolithography technique is used for patterning. For example, Ta formed using
It has a resistor layer 12 made of -SiO2 resistive thin film. Electrode parts 13 and 14 are formed facing each other on the resistor layer 12, and the electrode parts 13 and 14 are coated with, for example, a NiCr film 15 and an Au electrode thin film 16, respectively, in order to increase the adhesion to the substrate 21. It consists of Electrode part 13,1
There is a portion of the resistor layer 12 that is not covered by the electrode portions 13 and 14 between the opposed portions of the resistor layer 12 , and the resistor layer 12 in this portion serves as a heating resistor portion 17 . Furthermore, the heating resistor section 1
A protective layer 18 is deposited on the substrate 11 including the substrate 7 . Therefore, the portion from the heating resistor section 17 to the protective layer 18 above it serves as a heating section 19 that transfers heat to thermal recording paper, ink ribbon, or the like.

This thin film type thermal head has a structure in which a plurality of electrode parts 13, 14 and a heating resistor part 17, ie, a heating element part 19 are arranged, as a part of which is shown in FIG. When printing using the thin-film thermal head configured as described above, desired printing can be performed by selectively energizing each heating resistor section 17, as in the case of a thick-film thermal head. .

0010

[Problems to be Solved by the Invention] However, the conventional thermal head having the above structure has the following problems.

(A) In the case of a conventional thick-film thermal head, the resistor layer 4 is formed using a thick-film forming technique.
The resistance value varies widely due to factors such as variations in manufacturing conditions and non-uniformity of the forming material. Therefore, it is necessary to correct the resistance value using a trimming method such as pulse trimming in which the resistance value is changed by an annealing effect caused by flowing a current, to reduce the resistance value deviation, and to improve the resistance accuracy. Further, even if trimming is performed, it is difficult to accurately adjust the resistance value of each heating resistor portion 5 in a thick film type thermal head, and the head cannot be used as a gradation head.

(B) In the case of the conventional thin-film thermal head, when forming the pattern of the resistor layer 12 and forming the electrode section 13,
At the time of forming 14, patterning by photolithography process is required, for example, twice in total, which makes the manufacturing process complicated and increases the manufacturing cost.

Furthermore, in the thin film type thermal head, the heating element portion 19 is basically concave. Therefore, a gap is created between the heating element section 19 and the thermal recording paper, ink ribbon, etc., resulting in poor heat conduction efficiency and heat loss. In addition, cracks are likely to occur at the stepped portion of the heating element section 19, and when such cracks occur, for example, ions of the thermal recording paper component (for example, Cl-, etc.) or the ink ribbon may be removed due to voltage application during driving. Ink components may enter the electrode portions 13, 14 and heating resistor portion 17, leading to electric field corrosion (electrolytic corrosion), or impurities such as moisture may enter, leading to corrosion, which may reduce the durability and reliability of the head. resulting in deterioration of the

[0014] The present invention solves the problem that the prior art described above had, in that the thick film type has a large variation in the resistance value of each resistor and requires trimming, and cannot be used, for example, in a gradation head, and the thin film type We offer a thermal head that solves the problems of requiring multiple photolithography processes to form patterns for electrodes and resistors, and of causing electrolytic corrosion and heat loss due to the concave shape of the heating element. be.

[0015]

[Means for Solving the Problems] In order to solve the above-mentioned problems, a first invention includes a thermal head disposed facing each other on an insulating substrate, a first conductive layer formed on the insulating substrate, and a first conductive layer formed on the insulating substrate. first and second electrode parts each having a second conductive layer formed on an opposing portion of the first conductive layer;
an insulating step-embedded part provided around the conductive layer and exposing the upper surface of the second conductive layer to a predetermined height and embedding the periphery of the second conductive layer; and a heating resistor section formed by a resistor layer provided over the opposing portion of the electrode section and over the stepped embedded section in the specific area and connected between the first and second electrodes. This is what I did.

[0016] A second invention is the first invention, comprising:
The first and second conductive layers are made of thick films, and the resistor layer is made of a thin film.

A third aspect of the present invention provides a method for manufacturing a thermal head in which, after forming a first conductive layer on an insulating substrate, a first conductive layer having a predetermined shape is formed on the first conductive layer including a heating resistor portion formation region. forming a second conductive layer, and patterning the first and second conductive layers so that they face each other in the heat generating resistor portion forming region, and each facing portion is separated from the first and second conductive layers. forming first and second electrode parts in a laminated state; and depositing an insulating material to a predetermined thickness on the insulating substrate including the first and second electrode parts, and then a step of exposing the upper surface of the second conductive layer by a specific etching process to form a step-embedded part that embeds the periphery of the second conductive layer; A resistor layer is provided on the upper surface using a predetermined mask in an area including the heat generating resistor part forming area and wider than the heat generating resistor forming area, and is connected between the first and second electrode parts. The steps of forming the heating resistor portion are performed in sequence.

[0018] A fourth invention is, in the third invention,
After forming the heating resistor portion, a protective layer is subsequently formed on the resistor layer using the predetermined mask.

[0019]

[Operation] According to the first invention, since the thermal head is configured as described above, the first and second electrode portions have a laminated structure of the first and second conductive layers at the opposing locations. , serves to make the electrode portions at the opposing locations convex.

[0020] The step-embedding portion exposes the upper surface of the second conductive layer of the first and second electrode portions to a predetermined height (for example, including zero or almost zero), thereby increasing the height of the second conductive layer. The periphery of the insulating substrate is buried and the surface of the insulating substrate including the first and second electrode portions is flattened.

[0021] The heating resistor portion is disposed on the insulating substrate planarized by the step-embedded portion, and is in contact with the upper surface of the second conductive layer facing the first and second electrode portions. Works to connect. Here, the location where the heating resistor portion is formed is determined depending on the region where the second conductive layer is formed. That is, the heating resistor portion is a specific part of the resistor layer, and the specific part is between the opposing second conductive layers and about the width of the opposing second conductive layer. be. Therefore, the current between the first and second electrode parts is
Most of the current flows through a current path that is about the same width as the opposing width of the second conductive layer, and even if the resistor layer is formed in a portion other than the current path, almost no current flows there.

According to the second invention, in addition to obtaining the same effect as the first invention, the first and second conductive layers of the first and second electrode portions are made thick. This ensures a sufficient current path in the electrode portion, and by making the resistor layer thin, the thickness of the resistor layer can be set with high precision, and the resistance value of the heating resistor portion can be set with high precision. be done. According to the third invention, since the method for manufacturing a thermal head is configured as described above, first, the first conductive layer is formed on the insulating substrate, and then the first conductive layer including the heating resistor portion formation region is A second conductive layer having a predetermined shape is formed on the conductive layer. Here, the first and second conductive layers are usually one layer each, but each layer may be composed of a plurality of layers.

After forming the first and second conductive layers,
The first and second conductive layers are patterned to form first and second conductive layers in a laminated state that face each other in the heat generating resistor formation region and each opposing portion is comprised of the first and second conductive layers. Form an electrode part. As a result, the first and second electrode portions have a structure in which the second conductive layer protrudes at the opposing locations, so that at the opposing locations, the portions consisting only of the first conductive layer are larger than those at other locations. It also becomes more expensive.

[0024] Next, an insulating material is deposited to a predetermined thickness on the insulating substrate including the first and second electrode parts, and then the upper surface of the opposing second conductive layer is exposed. A step buried portion is formed to fill the periphery of the second conductive layer. As a result, the top surface of the insulating substrate including the first and second electrode parts is flattened, and only the top surface of the second conductive layer is exposed on the flattened surface at a predetermined height including zero. become.

Thereafter, a resistor layer is formed using a predetermined mask on the upper surface of the exposed second conductive layer and the step-embedded portion, including the region where the heating resistor portion is formed and wider than the heating resistor portion formation region. do. With this resistor layer, the first
A heat generating resistor section is formed between the opposing portions of the second electrode section and connects each electrode.

According to the fourth invention, after forming the heating resistor portion, a protective layer is subsequently formed on the resistor layer using the predetermined mask.

[0027] Therefore, the above problem can be solved.

[0028]

[Example] Figures 1 (a-1) to (c) and Figure 2 (d-1)
1 to (e) are a series of manufacturing process diagrams for explaining the structure and manufacturing method of the thermal head according to the embodiment of the present invention, and showing the method of manufacturing the thermal head according to the embodiment. Note that FIG. 1(a-2) shows a cross section taken along line C-C in FIG. 1(a-1), and FIG.
1) shows a cross section taken along line D-D in FIG.

According to the manufacturing method of this embodiment, a thermal head having the structural features of this embodiment is manufactured through the following steps (I) to (IV).

(I) Steps of FIGS. 1A-1 and 1A-2 For example, a glazed ceramic substrate 21 (hereinafter simply referred to as substrate 21) is prepared. For example, a thick film paste of resinate Au (organic gold) containing many organic substances is applied to the entire surface of the substrate 21 by screen printing or the like, thereby forming the first conductive layer 22 . For example, a thick band A is applied to the conductive layer 22 in a portion including the region where the heating resistor portion is formed.
A thick film paste of u is applied by screen printing etc.
A second conductive layer 23 is formed. As a result, if drying, firing, etc. are performed appropriately, the conductive layers 22 and 23 made of thick Au films can be formed.
is thickened in two layers. Note that during firing, in this example, the second
The resinate Au used for the conductive layer 22 contains more organic matter in the paste than the thicker Au, so most of the paste components are blown away, resulting in a thinner film than the thicker Au. Useful for later patterning.

After printing and baking the Au thick film in two stages, the conductive layers 22 and 23 are formed using photolithography and etching techniques.
are patterned, and the conductive layers 22 and 23 face each other, forming a laminated structure of conductive layers 22 and 23, with the conductive layer 23 protruding only at the opposing locations, and the first and second electrode portions 24 consisting of only the conductive layer 22 at other locations. , 25. At this time, the etching process can be carried out efficiently by adjusting the thickness of the first conductive layer 22 in advance to a level that does not deteriorate the current characteristics.

In this step, the electrode circuit is formed as described above, and usually a plurality of electrode parts 24 and 25 are arranged in accordance with the head structure. One of the plurality of sets of electrode sections 24 and 25 is commonly connected to a power source, for example, and the other is connected to a drive circuit or the like via, for example, a wire bonding section. In this wire bonding part, the wire bonding pad part is usually formed thick with two layers of conductive layers. Therefore, in this case, according to this process, just by changing the mask,
The first and second electrode parts 24 and 25 and the wire bonding part can be thickened (for example, about 1 μm) at the same time.

(II) Process electrode parts 24 and 2 in FIGS. 1(b) and 1(c)
5, an insulating material such as polyimide (insulating resin) is spin-coated onto the substrate 21 including the electrode parts 24 and 25. Then, as shown in FIG. 1B, a thin layer of polyimide remains on the surface of the conductive layer 23 in the thickened Au portion, and the other recesses are filled with polyimide. Thereafter, when the surface of the substrate 21 is etched by dry etching (ashing) using, for example, oxygen plasma, the conductive layer 2 is etched as shown in FIG. 1(c).
3 The top surface is exposed. This exposed portion will be
This is the terminal for connecting the resistor to 5. At this time, for example, the thickened Au portion of the wire bonding portion, which is also thickened in the same way, is exposed, and that portion becomes the wire bonding pad portion.

On the other hand, a step buried portion 26 made of polyimide is formed around the conductive layer 23. Step embedded part 26
embeds the periphery of the conductive layer 23, for example, at a height slightly lower than the upper surface of the conductive layer 23. Therefore, the step embedded portion 26 is
The surface of the substrate 21 is planarized with the upper surface of the conductive layer 23 exposed at a predetermined height.

(III) Steps in FIGS. 2(d-1) and (d-2) After the step (II) above, on the planarized surface consisting of the exposed upper surface of the conductive layer 23 and the upper surface of the step-embedded portion 26, For example, using a mask jig, a heating element such as Ta-SiO2 is deposited on an area including the area where the heating resistor part is formed between the exposed surfaces of the conductive layer 23 and a wider area than that, and then forming a thin film resistor layer. form 27. The resistor layer 27 of this embodiment is formed in a strip shape, and its width is set to the opposite width of the conductive layer 23 (for example, 11
0 to 250 μm).

In forming the resistor layer 27, the mask jig is, for example, a stainless steel plate with a slit-like window, and the deposition method is, for example, mask sputtering. Further, the shape of the window provided in the mask jig is set depending on the shape and size of the resistor layer 27 to be formed.

(IV) Process of FIG. 2(e) After forming the resistor layer 27, the mask jig used for forming the resistor layer 27 is used as it is, and SiAlON or silicon is formed by, for example, sputtering. A protective layer 28 is formed by depositing nitride (Si3 N4) or the like on the resistor layer 27.

The thermal head of this embodiment is manufactured in the manner described above.

In the thermal head of this embodiment, the conductive layer 23 portions of the first and second electrode portions 24 and 25 are in contact with the resistor layer 27. Therefore, when a current flows between the electrode parts 24 and 25, most of the current flows between each electrode part 24 and 25 in a current path that is about the width of the opposing conductive layer 23. Therefore, in the resistor layer 27, the portion above between the conductive layers 23, which serves as the current path, becomes the heating resistor portion 29. Further, from this heating resistor portion 29 to the protective layer 2 above it,
The part 8 becomes the heating element part 30.

In the structure and manufacturing method of the thermal head of this embodiment, a plurality of the electrode parts 24, 25 and the heating resistor part 29, that is, the heating element part 30 as described above are arranged. There is. In addition, in the thermal head of this embodiment, the resistor layer 27 is formed into a band shape that is commonly used for each dot. The dots are electrically and thermally independent from each other.

When printing is performed using the thermal head as described above, electricity is selectively applied between each set of electrode portions 24 and 25 by the output of a drive circuit, a control circuit, etc. (not shown). Then, between the selected electrode parts 24 and 25, a current flows through the resistor layer 27, that is, the heating resistor part 29, between the opposite widths of the conductive layer 23, and the heating element part 30 in that part generates heat. Therefore, for example, when each heating element section 30 is brought into contact with a thermal recording paper fed by a platen, an ink ribbon, etc., the thermal recording paper facing the heating point develops color due to the transfer of heat from the heating element section 30. Or the ink from the ink ribbon is transferred to plain paper. Therefore, by feeding the thermal recording paper, or the ink ribbon and plain paper, desired characters, numbers, symbols, figures, etc. can be printed.

This embodiment has the following advantages.

(a) According to the structure of the thermal head of this embodiment, the surface of the substrate 21 consisting of the upper surface of the conductive layer 23 and the upper surface of the step-embedded portion 26 has a nearly flat convex structure, and a thin film resistor is disposed thereon. Since the layer 27 is formed, a thin film heating resistor portion 29 with good coverage can be formed. For this reason, while taking advantage of the advantage of a thin film resistor that does not require resistor trimming, it also has the disadvantage of poor thermal efficiency due to the concave structure of the heating element of the conventional thin film thermal head.
It is possible to solve the disadvantage that functional deterioration such as electrolytic corrosion occurs due to the stepped portion. That is, in the thermal head of this embodiment, the heating element portion 30 has a nearly flat convex structure, which provides good contact with thermal recording paper, transfer film, etc., improves thermal efficiency, and improves film coverage. This makes it possible to improve the durability and reliability of the head.

(b) Furthermore, in the structure of the thermal head of this embodiment, the electrode portions 24 and 25 are located below the resistor layer 27. Therefore, even if the thickness of the electrode parts 24 and 25 is increased in order to improve electrical characteristics such as permissible power in the electrode circuit, the contact area between the heat-sensitive recording paper, ink ribbon, etc. and the heating element part 30 will not generate heat. There is no possibility that the thermal efficiency will be degraded or the contact state will be impaired by being separated from the resistor section 29. Therefore, if the electrode parts 24 and 25 are made of thick films and the thickness is set to a level that does not interfere with patterning,
While improving the coverage and contact state, a sufficient current path can be secured for the electrode parts 24 and 25 without increasing the electrode circuit area. Therefore, for example, the allowable power can be increased, the electrical characteristics are improved, the electrical reliability of the electrode circuit is increased, and the effect of reducing power loss can be expected.

(c) In the method for manufacturing a thermal head of this embodiment, after an insulating material such as polyimide is deposited on the substrate 21 in the step (II) above, a dry etching process using oxygen plasma or the like is performed. (plasma ashing)
Thus, a step buried portion 26 is formed to expose the upper surface of the conductive layer 23. Therefore, the process of forming the step-embedded portion 26 and exposing the upper surface of the conductive layer 23 can be simplified,
It also improves controllability and is highly reliable.
Achieve optimal process design.

(d) According to the method of manufacturing a thermal head of this embodiment, by working together with the structure of the thermal head in which the opposing portions of the electrode parts 24 and 25 are made into two layers and are used as connecting terminals between the electrodes, When forming the heating resistor portion 29,
It is possible to provide a margin for the formation size of the resistor layer 27.

In general, it is extremely difficult to obtain a typical heating resistor width of about 110 to 250 μm using a thin film forming method such as mask sputtering. Therefore, in order to achieve this heating resistor width, it is currently necessary to rely on thick film printing technology or thin film photolithography and etching technology. However, thick film printing technology, photolithography technology, and etching technology all have complicated processes and a large number of steps, and it is best from the viewpoint of manufacturing time and manufacturing cost to avoid using these as much as possible.

However, in the manufacturing method of this embodiment, the width of the Ta-SiO2 deposited film by mask sputtering is 1
Even if the width is 2 mm, most of the current flows between the opposing widths of the conductive layer 23 (110 to 250 μm), so heat is generated in this region, and as a result, the width of the heating resistor portion 29 is 110 to 250 μm.
The thickness can be approximately 250 μm.

As described above, in the method for manufacturing the thermal head of this embodiment, when forming the heating resistor portion 29, the formation size of the resistor layer 27 can be widened with a margin, so that a mask using a simple mask jig can be used. The resistor layer 27 can be formed by a method such as sputtering, eliminating the need for photolithography, etching, etc., reducing manufacturing time, reducing the number of manufacturing steps, improving work efficiency, and reducing manufacturing costs.

(e) Furthermore, in the method of manufacturing the thermal head of this embodiment, it is possible to extend the resistor region that is not directly involved in heat generation to the protective film region.
The protective film region and the resistor region are formed in the same region, and the protective layer 28 is continuously formed on the resistor layer 27 using the same mask jig used for forming the resistor layer 27. I did it like that.

If the protective layer 28 and the resistor layer 27 are not formed in the same area, but are to be formed in different areas by changing the mask, once the vacuum of the film forming apparatus is broken, the setting is changed, and then the process is performed again. It is necessary to evacuate and apply a film. However, according to the manufacturing method of this embodiment, by continuously forming the resistor layer 27 and the protective layer 27 in the same area using the same mask, it is possible to reduce unnecessary processes associated with changing masks, etc., and improve manufacturing efficiency. and can promote the effect of reducing manufacturing costs.

It should be noted that the present invention is not limited to the illustrated embodiment, but can be modified in various ways. Examples of such modifications include the following.

(i) The structure of the thermal head of the above embodiment includes a substrate 21, conductive layers 22 and 23, and electrode parts 24 and 2.
5. The shape, forming material, arrangement, etc. of the step embedded portion 26, the resistor layer 27, and the protective layer 28 can be variously modified. The configuration of the section 30 and the like can also be modified in various ways.

For example, in the above embodiment, the step embedded portion 2
6. The height of the top surface of the conductive layer 23 is set so that the top surface of the conductive layer 23 has a convex structure that does not impede good coverage. , their surfaces may be kept flat. Further, at this time, for example, by providing an arc-shaped partial glaze on the surface of the substrate 21, the surface on which the resistor layer 27 is formed is smoothed and the coverage is improved, and the contact condition with, for example, thermal recording paper or thermal transfer film, etc. The heat conduction efficiency may be improved. In this case, according to the present invention, even if the electrode circuit constitutes a thick film, the paper contact property will not be impaired.

(ii) The method for manufacturing the thermal head of the above embodiment can be modified in various ways, including the manufacturing procedure, manufacturing means, materials used, etc.

For example, in the above embodiment, mask sputtering was used to form the resistor layer 27 and the protective layer 28, but this could also be done by, for example, a printing method using a simple mask jig. You can also do it.

[0057]

Effects of the Invention As described above in detail, according to the first invention, the first and second electrode portions, the step embedded portion,
Since the thermal head is configured by providing the heat generating resistor section, the heat generating resistor section can be formed with good coverage, achieving good thermal efficiency with little heat loss, and high reliability with no functional deterioration due to electrolytic corrosion etc. It is possible to provide an excellent thermal head that provides high performance and printing efficiency.

According to the second invention, the same effects as the first invention can be obtained, and the first and second conductive layers of the first and second electrode portions are made of thick films. By doing so, a sufficient current path can be secured, electrical characteristics such as allowable power can be improved, electrical reliability in the electrode circuit can be increased, and the effect of reducing power loss can also be expected. Furthermore, by forming the resistor layer as a thin film,
The resistance value of the heating resistor portion can be set with high accuracy. Therefore, it is possible to realize a thermal head that has no unevenness in print density due to the uniform heat generation of the heating resistor portion, is fully applicable to gradation heads, etc., and has extremely low power consumption loss.

According to the third invention, since the thermal head is manufactured by passing through each of the steps in order, when forming the step-embedded portion, the insulating material is deposited to a predetermined thickness; By subsequently exposing the upper surface of the conductive layer through a specific etching process, the steps of forming the step-embedded portion and exposing the upper surface of the conductive layer can be performed in a simple process with good controllability.

Furthermore, when forming the heating resistor portion,
Considering the electrode structure formed in the step of forming the first and second electrode sections, the resistor layer is made wider than the region where the heating resistor section is formed. The fineness of the region can be relaxed. Therefore, as the specific mask, a simple mask with a window pattern formed on a mask base material such as stainless steel is used instead of a complicated one using photolithography technology, etc., thereby simplifying the manufacturing process and reducing the manufacturing time. It is possible to achieve reductions in manufacturing costs.

According to the fourth invention, the same effects as the third invention can be obtained, and the resistor layer and the protective layer are successively formed in the same area using the predetermined mask. As a result, redundant processes associated with mask replacement, for example, can be eliminated, the manufacturing process can be optimized, and manufacturing costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram showing a method for manufacturing a thermal head according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram showing a method for manufacturing a thermal head according to an embodiment of the present invention.

FIG. 3 is a partial configuration diagram of a conventional thick-film thermal head.

FIG. 4 is a partial configuration diagram of a conventional thin film thermal head.

[Explanation of symbols]

21　Substrate 22 First conductive layer 23 Second conductive layer 24, 25 Electrode part 26 Step embedded part 27 Resistor layer 28 Protective layer 29 Heating resistor part 30 Heating element part

Claims (4)

[Claims] 1. A first conductive layer disposed oppositely on an insulating substrate and having a first conductive layer formed on the insulating substrate and a second conductive layer formed on an opposing portion of the first conductive layer. an insulating step provided around the first and second electrode portions and the second conductive layer, exposing the upper surface of the second conductive layer to a predetermined height and embedding the periphery of the second conductive layer; A connection between the first and second electrodes is formed by a buried portion and a resistor layer provided over the opposing portions of the first and second electrode portions and over the step buried portion in a specific area. What is claimed is: 1. A thermal head comprising: a heat generating resistor section; 2. The thermal head according to claim 1, wherein the first and second conductive layers are made of thick films, and the resistor layer is made of a thin film. 3. After forming a first conductive layer on an insulating substrate, forming a second conductive layer having a predetermined shape on the first conductive layer including the heating resistor portion formation region; The first and second conductive layers are patterned so that they face each other in the heat generating resistor forming region, and their respective opposing portions are formed in the first conductive layer.
and forming first and second electrode parts in a laminated state consisting of a second conductive layer, and depositing an insulating material to a predetermined thickness on the insulating substrate including the first and second electrode parts. After that, a step of exposing the upper surface of the second conductive layer that faces the second conductive layer by a specific etching process to form a stepped buried portion that embeds the periphery of the second conductive layer; and a resistor layer is provided using a predetermined mask in an area including the heating resistor forming area and wider than the heating resistor forming area on the upper surface of the step embedded part, and forming the first and second resistor layers. 1. A method for manufacturing a thermal head, comprising sequentially performing the steps of forming a heating resistor section connected between electrode sections. 4. The method of manufacturing a thermal head according to claim 3, further comprising forming a protective layer on the resistor layer using the predetermined mask after forming the heating resistor portion. Method.