JPH0321462A - Thermal head substrate and production thereof - Google Patents

Abstract

PURPOSE:To obtain a good contact between a platen roller and a heating part through a wear resistant layer by providing a lower electrode body layer on the surface of an insulating substrate other than a heating part of a resistor layer and an upper electrode body layer on the surface of the lower electrode body layer out of an area larger than and including the heating part. CONSTITUTION:A TiSiO2 film is formed as a resistor layer 2 on a glazed alumina substrate 1. Next, after an Al film is formed as a lower electrode body layer 4, a TiSiO2 film is formed as an intermediate metal layer 5, and an Al film is formed as an upper electrode body layer 6. A part of the Al upper electrode body layer 6 larger than in area and including a heating area 3a is removed by etching to form an Al pattern of the upper electrode body layer 6 with the intermediate metal layer 5 of TiSiO2 film exposed. After that, the intermediate metal layer 5 of TiSiO2 film is removed by dry etching. At this time, the TiSiO2 film selectively separates the Al film as the lower electrode body layer 4 from the Al film as the upper electrode body layer 6. Then, a part of the Al lower electrode body layer 4 is etched to form an Al pattern, and the resistor layer 2 thereunder is removed by etching to form an Al conductor pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head substrate and a method for manufacturing the same, and particularly to the film structure of an electrode body.

[Conventional technology]

A thermal head board generally has a resistor on an insulating board,
The metal wiring pattern connected to it is formed using film technology. FIGS. 4(a) and 4(b) are a plan view and a sectional view taken along the line AA' of a part of the electrode structure of an example of a conventional thermal head substrate.

The thermal head substrate has a resistor layer 2 provided on a glazed alumina substrate 1, and electrode bodies 14a and 14b connected to both ends of this surface for supplying power.

The region of the resistor layer 2 from which the electrode bodies 14a and 14b have been etched away becomes the heat generating portion 3.

A wear-resistant layer 1 is provided on the surfaces of the heat generating part 3 and the electrode bodies 14a and 14b.
7 is provided.

[Problem to be solved by the invention]

When printing is performed using the conventional thermal substrate described above, the heat generating section 3 is pressed against the platen 9 via the thermal paper 8.

In this type of thermal head substrate, the electrode body 14a
, 14b, the dot-shaped heat-generating portion l3 is located below, so that the left and right edges P of the lead-shaped electrode bodies 14a, 14b near the heat-generating portion 3 come into contact with the thermal paper 8, and the heat-generating portion 3
There is a risk that the paper may not come into contact with the thermosensitive paper, and sufficient print density may not be obtained. Moreover, as a result of applying excessive force to the left and right edges of the electrode bodies 14a and 14b, there is a possibility that the wear-resistant layer 17 may be peeled off at the left and right edges P of the electrode bodies.

In order to eliminate this fear, the film thickness of the electrode body can be reduced, but there is a limit to how thin the film thickness can be because it is necessary to keep the increase in the conductor resistance value of the electrode body to a minimum.

[Means to solve the problem]

The thermal head substrate of the present invention includes: a resistor layer formed on the surface of an insulating substrate and having a heat generating part in a part; a lower electrode layer formed on the surface of the resistor layer other than the heat generating part;
An upper electrode body layer is formed on the lower electrode body layer, including the heat generating part and excluding the peripheral edge thereof.

Further, in the method for manufacturing a thermal head substrate of the present invention, after forming a resistor layer on an insulating substrate, an intermediate metal layer that can be selectively etched with a lower electrode layer, and an upper electrode layer made of the same material as the lower electrode layer. are sequentially laminated, and then the upper electrode layer is etched away over an area larger than the area of the heat generating part including part of the heat generating part of the resistor layer, and then the intermediate metal layer is etched. After the removal, a conductive circuit including the lower electrode layer and the resistor layer is formed, and then the lower electrode layer on the surface of the heat generating part is removed. [Example] 1(a) and 1(b) are a partial plan view and a cross-sectional view taken along the line A-A' of the first embodiment of the present invention, and FIG.
1A to 1E are cross-sectional views of the in-process substrate shown in the order of steps for explaining the electrode structure of the substrate and its manufacturing method for the Therma At shown in FIG. 1;

First, as shown in FIG. 2(a), a T.sub.2 resistor layer 2 is formed on a glazed alumina substrate 1. Si02 film about 0.1
A film was formed to a thickness of ~0.2 μm, and then an Al film was formed as the lower electrode body layer 4.
After forming the film to a thickness of approximately 0.3 μm, T.
SiO2 approx. 0. 1 ~ 0. After coating to a thickness of 2 pm,
Further, as the upper electrode body layer 6, an AA film having a thickness of approximately 0.7 μm is formed by sputtering. Next, Figure 2 (
As shown in b), a photoresist processing technique is used to form a heating region 3. The area including the T.I. An AA pattern of the exposed upper electrode body layer 6 of the intermediate metal layer 5 of the SiOz film is formed.

Next, as shown in FIG. 2C, dry etching is performed using 02+CF4 gas to remove the Nakaseki metal layer 5 of the TaSiO2 film.

At this time, the T a SiO 2 film selectively separates the Ai+ film, which is the lower electrode body M4, and the Aβ film, which is the upper electrode body layer 6.

Next, as shown in FIG. 2(d), a part of the Ano lower electrode body layer 4 is etched with a phosphoric acid and nitric acid-based etchant to form a pattern A[, and then the resistor layer underneath is etched. 2 is removed by etching with a mixed etchant of hydrofluoric acid and nitric acid to form an AA conductor pattern. Next, as shown in FIG. The heat generating part 3 is formed by masking other parts with photoresist and removing it with a phosphoric acid and nitric acid based etchant.

Finally, as shown in FIG. 1(b), the heating section 3 lower electrode body layer 4. , 4, and a common electrode 6 formed from 6 of the upper electrode body layer.
The surface of the individual electrode body 6 is covered with a wear-resistant layer 7, and a thermal head substrate is completed.

As shown in FIGS. 1(a) and 1(b), in the thermal head substrate, a conductor circuit 10 for energizing the heat generating part 3 of the resistance layer 2 is formed into a heavy film with an intermediate metal layer 5 sandwiched therebetween. Further, the edge of the electrode body on the heat generating part 3 side on the resistor layer 2 has a two-stage structure.

In this way, while keeping the conductor resistance value to a minimum, the electrode film resistance near the heat generating part 3 is made thinner by making it one step of the lower electrode body layer.
A plan view showing a sufficient printed conductor arrangement that allows sufficient contact with the
-A' line sectional view.

As shown in FIG. 3(a), an AA film with a thickness of about 1.0 μm is used as the lower electrode body layer 4, and a NiC film is used as the intermediate metal layer 2.
r film to about 0. After forming an Aj7 film with a thickness of 1 μm and a thickness of about 3.0 μm as the upper electrode body layer 6, the common electrode resistance was 6.0 μm. Only the intermediate metal layer 5, the lower electrode body layer 4 sandwiching N i Cr,
Af[ of the common electrode body 6 and A{of the common electrode body 6 are made of a heavy film.

The manufacturing process is similar to the first example, but NiCr
Selective etching with respect to the An film is performed using a mixed solution of ceric ammonium nitrate and perchloric acid as a film etching solution.

In this embodiment, in order to lower the conductor resistance value of the common electrode portion, the common electrode portion 6. This is effective in placing emphasis on increasing the thickness of the material. Further, if NiCr is used as the intermediate metal layer 5, a dry etching device is not necessary, and selective etching and etching can be performed by wet etching, which is convenient.

In this embodiment, only the common electrode body through which a large current flows is made of a heavy film, so that even when a large current flows, the difference in applied voltage depending on the printing position on the substrate due to the voltage drop can be reduced, and good printing can be obtained. I can do it.

〔Effect of the invention〕

In the present invention as described above, first, a lower electrode layer is formed on the surface of an insulating substrate, and a lower electrode layer is provided on the surface of the resistor layer 20 other than the heat generating portion, and the surface of the lower electrode layer is An upper electrode body layer is provided on the heat generating part, and the electrode body on the periphery of the heat generating part has a two-stage structure, which has the effect of making good contact between the platen roller and the heat generating part via the wear-resistant layer.

7... Abrasion resistant layer, 8 Thermal paper, 9... Platen roller, 10... Conductor circuit.

Claims (2)

[Claims] (1) A resistor layer formed on the surface of an insulating substrate and having a heat generating part in a part, a lower electrode layer formed on the surface of the resistor layer other than the heat generating part, and a lower electrode layer including the heat generating part. A thermal head substrate comprising an upper electrode body layer formed on the lower electrode body layer except for the peripheral portion. (2) After forming a resistor layer on an insulating substrate, a lower electrode layer, an intermediate metal layer that can be selectively etched, and an upper electrode layer made of the same material as the lower electrode layer are sequentially laminated, and then The upper electrode body layer is etched away over an area larger than the area of the heat generating part region including a part of the heat generating part of the resistor layer, and then the intermediate metal layer is etched away, and then the lower electrode body layer is removed by etching. and the resistor layer, and then removing the lower electrode layer on the surface of the heat generating part.