JPS583884A - Heat generating resistor for heat sensitive recording head and production thereof - Google Patents

Abstract

PURPOSE:To produce a heat generating resistor which is free from cracks in its oxidation resisting layer and wear resisting layer by such an arrangement wherein the outer circumference of an adhesion layer pattern at the upper layer of a heat generating resistor layer is formed inside the outer circumference of the resistor layer and the outer circumference of a wiring layer pattern at the upper layer of the adhesion layer is formed inside the outer circumference of the adhesion layer. CONSTITUTION:A glazed glass layer 2 and an etching resisting layer 3 of a resistor are formed on a substrate 1 and a wiring unit is formed by providing a resistor layer 4, an adhesion layer 5 and a wiring layer 6 on the substrate by photoetching method. At this time, etching is performed in the order of the wiring layer 6, adhesion layer 5 and resistor layer 4, and after that reetching is performed in the order of the adhesion layer 5 and the wiring layer 6 and by this the adhesion layer 5 and the wiring layer 6 are properly shaped to the free from overhangs. In forming a resistor unit, etching is performed in the order of the wiring layer 6 and the adhesion layer 5 and then the wiring layer 6 is reetched. Said heat generating resistor can be obtained by forming an oxidation resisting layer 7 of the resistor and a wear resisting layer 8 in the next stage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistor for a thermal recording head and a method for manufacturing the same.

A conventional heating resistor of this kind, for example, a thin-film thermal recording head, is shown in plan view in Figure 1 (A) and in Figure 1 (B) (/→
As shown in the cross-sectional views in FIG. 1, a thermal storage glaze glass layer 2 and a lower Tam O layer 3 as an etching-resistant layer for the resistor are formed on almost the entire surface of the substrate 1, and a desired shape is formed on the alumina substrate 1. A resistor layer 4 is formed as appropriate, and this resistor layer 4 is bonded to the wiring layer 6 thereon by an adhesive layer 5, and SiO, SiO, etc. are further formed as an oxidation-resistant protective layer of the resistor.
A layer 7 is formed over the entire structure, and an upper Ta1011 layer 8 is formed as a wear-resistant layer.

The planar shape of the resistor has a length l> in Fig. 1 (a).
= 250 μm, width 6 = 4 μm, and such a resistor has a pitch of 1. : 125 μm and the desired number of devices. (In the figure, the resistor layer 4 is marked with fine dots. Also, to make the illustration clearer, FIG. 1 (B) is a cross-sectional view (the occlusions for /→ are omitted).

However, in such a conventional example, because of the above-described structure, recesses 9 and 9' are inevitably formed in the manufacturing process, and a number of problems arise accordingly.

Such recesses 9 and 9' are subjected to large stress during sputtering, and cracks occur due to the heat generation cycle caused by pulse voltage energization of the resistor, and oxygen, moisture, etc. in the air are supplied to the resistor through these cracks, and the resistance increases. In addition, when the thermal paper is driven, the chlorine valve, which is a component of the thermal paper, melts due to heat generation and penetrates through cracks, causing deterioration of the resistor and wiring layer.

That is, the conventional thin film resistor mentioned above is usually formed by sputtering or vacuum evaporation, and the resistor thin film is a pulse-resistant thin film of Cr-81 alloy or the like.

The wiring layer is A! , a low resistivity thin film such as An, and a Cr or Ni-Cr thin film as the adhesive layer. In this case, for the patterning of the shape shown in FIG. 1 (a) above,
Conventionally, a normal photoetching process has been applied, and the formation process is as shown in FIG. 2. As shown in FIG. In the lower layer 'ratosl! V is formed, and then a resistor layer 4 is formed thereon. Adhesive layer 5. The process of forming the wiring layer 6 begins.

First, a resistor thin film, an adhesive layer thin film, and a wiring layer thin film are sequentially sputtered over the entire surface (Steps 1 to 5), and photoresist coating, exposure, and development are performed in Step Adhesive layer etching and resistor layer etching are performed to remove the 7th photoresist (Steps ① to ℃), and then in Step ③, photoresist coating, exposure, and
The current eye is etched, the wiring layer is etched, the adhesive layer is etched, and finally the resistor layer (4) is removed. This results in an adhesive layer of 5° and a wiring layer of 6v. In this step, when etching the wiring layer and adhesive layer, it is necessary to process the entire surface of the substrate. However, since the etching speed of the peripheral portion of the substrate is faster than that of the central portion of the substrate, the wiring layer 6 obtained by etching in this case has a higher etching rate than the upper layer 7.
The side of the photoresist pattern is etched by 1 to 2 μm from the periphery, and the adhesive layer 5 is etched by 1 to 2 μm from the wiring layer 6 above it.
The resistor layer 4 is also etched from the adhesive layer 5 to
The sides will be etched by 2 μm. Therefore, as shown in FIG.
The structure is such that it protrudes beyond the outer periphery of the adhesive layer 5. An oxidation-resistant layer and a wear-resistant layer t are sputtered on such a structure (step W, step Ⅰ), but if there is side etching in the adhesive layer 5 and resistor layer 4 as described above, as shown in the figure, The wiring layer 6 overhangs the adhesive layer 5, and the adhesive layer 5 overhangs the resistor layer 4, resulting in poor step coverage during sputtering. Figure 1 (b)
(Concavities 9 such as /→ inevitably occur.

Such a recess 9 is subject to large stress during sputtering. Therefore, when actually used as a heating resistor, cracks may occur here due to the heating cycle caused by pulse voltage energization of the resistor. Oxygen and moisture in the air are supplied to the resistor through these cracks,
As a result, oxidative deterioration of the resistor may occur. In addition, chlorine, etc. contained in the thermal paper is eluted due to heat generation and reaches the resistor and wiring layer through the cracks, causing deterioration and shortening of the lifespan of these.

In view of the above circumstances, the present invention aims to reduce the recesses in the anti-oxidation layer and wear-resistant layer of the resistor as described above, which cause cracks, and thereby reduce the oxidation-resistant layer, which causes deterioration of the resistor and wiring layer. Another object of the present invention is to provide a long-life heating resistor for a thermal recording head that prevents the occurrence of cracks in the wear-resistant layer, and a method for manufacturing the heating resistor.

In order to achieve this object, in the heating resistor for a thermal recording head of the present invention, the outer periphery of the pattern of the adhesive layer on the lowermost heating resistor layer is formed inside the outer periphery of the resistor; Further, the outer periphery of the pattern of the wiring layer located above the adhesive layer is formed so as to be inside the outer periphery of the adhesive layer.

In other words, the reason why concavities that cause cracks occur in the conventional technology is that the adhesive layer, which is the upper layer of the resistor layer, protrudes beyond the outer periphery of the resistor layer before forming the oxidation-resistant layer. This is because the wiring layer above the adhesive layer protrudes beyond the outer periphery of the adhesive layer and overhangs. Therefore, if the outer periphery of each upper layer is placed inside the outer periphery of the lower layer, overhang will not occur, so no recesses will occur, and various problems associated with cracks will not occur. The conventional problems will be wiped out.

In the present invention, the heating resistor having such a structure is manufactured by a photoetching method, and the etching order is set to the wiring layer and the adhesive layer.

It can be obtained by using a manufacturing method in which a resistor layer, an adhesive layer, and a wiring layer are formed in this order.

In other words, the overhang that causes the disadvantage of the conventional example is
This was caused by side etching during etching, but as a result of extensive research, the inventors of the present invention succeeded in reducing this overhang and improving the step coverage of the layer formed thereon by reversing the side etching. The present invention has been achieved by effectively utilizing the present invention.

Before explaining the embodiments, an outline of this technology will be explained. In the conventional resistor forming process shown in FIG.
The cross-sectional shape of the wiring section at the end of the resistor layer etching in step (2) is as shown in Figure 3 (a), and the wiring layer 6
And the adhesive layer 5 overhangs on the resistor layer 4. However, if the adhesive layer 5 is then re-etched using an eratint, the adhesive layer 5 will be side-etched and will fit inside the outer periphery of the resistor layer 4 as shown in FIG. Part 1 will be gone. Furthermore, when the wiring layer 6 is re-etched with eratint,
Similarly, as shown in FIG. 3C, the wiring layer 6 is contained within the outer periphery of the adhesive layer 5, resulting in a shape without overhang. Based on the same idea, it is possible to improve the steps (1) and (XI) in FIG. 2 for forming the resistor portion. That is, Article XI
After the adhesive layer etching step in the process, the wiring layer 6 is attached to the adhesive layer 5 with an oat (-
) 1, but by re-etching the wiring layer 6, the wiring layer 6 is automatically etched.
It can be made into the shape shown in FIG. 3 (E) without any hangs.

After this, the resistor oxidation-resistant layer 7. When the wear-resistant layer 8 is formed, the cross section of FIG.

It is possible to obtain a product with significantly improved step coverage of 7.8 degrees on both layers, as shown in Figure (B) (cross section of the resistor section). (Also in Figures 3 and 4, the cross section 71 has been omitted for clarity.)
.

An example of implementing the present invention will be specifically described below.

In this example, first, a glaze glass layer 2v with a thickness of 0 μm is placed on a 140 x 40 cm alumina substrate 1 with a thickness of 1.2
A substrate is formed on which Ta 1ksoo is formed.
Sputter with i thickness. The phantom was thermally oxidized at 500°C in oxygen for 1h1, resulting in a thickness of 1250X f>Ta,
01 layer is formed. Further on top of this is a Cr layer 81 =
C using an alloy target of 30/70 (atomic % ratio)
1500λ of alloy thin film on r-8 by sputtering method
Form to a thickness of . On top of that, Cr'k with a thickness of 1000λ and A layer with a thickness of 2 μm are formed by sputtering. The Cr-S1 alloy thin film serves as the resistor layer 4, and the Cr layer and the A1 layer serve as the adhesive layer 5. The wiring layer 6 is also σ). After this, etching is performed using a normal photo-etching process. In this case, the etching order is as follows: first, M, which is to constitute the wiring layer 6, is etched for about 5 minutes in a solution of phosphoric acid: nitric acid: acetic acid: water = 75:5:15:5 (volume %) at a temperature of 50°C, and then bonded. Etching was performed for about 3 minutes with a 15% by weight solution of Cr'lk ceric ammonium nitrate to form a layer, and then etching was performed using 7-acid: nitric acid =
A 1:30 (volume %) solution contains Cr − which becomes the resistor layer.
The St film is etched for a few seconds.

This is followed by further etching with a Cr etchant as described above for about a leap second, followed by etching with an AJ etchant also as described above for about 1 minute. Thereafter, the photoresist is removed to complete the etching of the wiring portion.

In this way, when etching the wiring part, the wiring layer (1
1 layer), adhesive layer (CCr layer), and resistor layer (Cr-8i film), and then further adhesive layer (Cr layer).
, wiring layer CAJ layer) in this order,
As explained using Figure 3 (A), (B), (/→), it is possible to obtain a resistor with no overhang as shown in Figure 3 (C).Similarly, the following resistor Also in forming photo ridges, the method explained in (e) in FIG. 3 is used to eliminate overhang. That is,
In the photo-etching process for forming the resistor, the A layer, which will become the wiring layer, is first etched with the above-mentioned elatint for about 5 minutes, and then the Cr%, which is to become the adhesive layer, is etched with the above-mentioned chromium etchant. Then, etching is performed for about 3 minutes, and then etching is performed again for about 1 minute on the Al layer.

In this way, in photo-etching for resistor formation, the wiring layer (11 layers) and the adhesive layer (Cr layer) are etched in this order, and then the wiring layer (Ali) is v-c etched, as shown in FIG. ) is oat; σ) that can obtain a state without -1 ringing. This is due to the reasons already explained using FIG. Such a manufacturing method of this example is shown in a process diagram in FIG.

Through the above steps, patterning of resistors and wiring conductors arranged at a pitch of 125 μm in a resistor layer having a width (A) μm and a length of 250 μm is completed. Next, on the substrate obtained in this way, Stosq3pm was applied as a resistor oxidation-resistant layer.
Further, on top of that, a wiring layer 6 is formed as a wear-resistant layer with a thickness of T&tOsY 2 μm each to complete the formation of the heating resistor.
．． Adhesive layer 5. When forming the resistor layer 4, overheight as in the conventional method does not occur, so a resistor oxidation-resistant layer 7 is formed on the resistor layer 4 by sputtering. Even if the resistor wear-resistant layer 8 is formed, its cross-sectional structure will be as shown in FIGS. 4(a) and 4(b).
) does not occur at all.

Therefore, a number of conventional problems caused by the presence of the recesses are also solved, and cracks are generated in certain parts of the recesses due to the heat generation cycle caused by pulsed voltage energization. The elution valve of chlorine, etc., which is a component of thermal paper, is reliably prevented from being supplied to the resistor, and the deterioration of the resistor is kept to a minimum, resulting in a significant improvement in the lifespan of the resistor. .

In fact, for each heating resistor obtained in the above example, 0.9m5
Specified concentration with a pulse width of 11e! When a power of 0.6WY was applied to this resistor, the rate of change in resistance of this resistor was within 10% even after applying 1Xio' pulse. On the other hand, the lifespan of resistors formed using conventional specifications is 3.
X 10” Since it was broken after applying Hals,
In comparison, it can be said that the product obtained by the present invention has a significantly extended lifespan.

As mentioned above, the heat-generating resistor for a thermal recording head of the present invention has a structure in which the oxidation-resistant layer and the wear-resistant layer of the resistor are damaged due to the overheating that conventionally occurs when forming wiring layers, adhesive layers, resistor layers, etc. There was a depression! As a result, it is possible to eliminate such recesses, and as a result, cracks do not occur in the recessed portions (1. Oxygen and moisture in the air or elution of thermal paper components from the cracks to the resistor Since chlorine is not applied, deterioration of the resistor can be minimized, and its lifespan can be greatly improved, making it possible to extend its lifespan.

In addition, the method for manufacturing a heating resistor of the present invention can reliably obtain the above-mentioned advantageous resistor through a simple process, and mass production is also easy because it only requires the use of the normal photo-etching process. It has the following advantages.

In addition, in the above-mentioned embodiment, C is used as the heating resistor layer.
R-81 alloy thin film, CRS as adhesive layer, A as wiring layer
/, 5IOt1 as a resistor protective layer, TalOa%r as a resistor wear-resistant layer, but for example, At1 can be used as an adhesive layer, HICrs can be used as a wiring layer, silicon nitride can be used as a resistor protective layer, and other suitable materials can be used. It is also possible to adopt other materials. As a matter of course,
The present invention should not be limited only to the embodiments described above.

[Brief explanation of the drawing]

Fig. 1 shows a conventional example, Fig. 1 (a) is a plan view, Fig. 1 (b) and Fig. 1 G/→ are respectively cross-sectional views taken along lines &-&' and b-b' in Fig. 1 (a). It is. FIG. 2 is a diagram showing a conventional process for forming a resistor. FIG. 3 is a schematic cross-sectional view for explaining the present invention in detail, and (A) to (E) are schematic cross-sectional views for each forming process. Figure 4 (
(a) and (b) are schematic cross-sectional views of a resistor portion and a wiring portion of a resistor obtained by an example of the implementation of the present invention. Fifth
The figure is a process diagram showing an example of a method for manufacturing the resistor. 4... Resistor layer, 5... Adhesive layer, 6... Wiring layer. Representative Patent Attorney Masami Akimoto (c) Figure 2 Figure 3 Figure 4 Figure 5 Continued from Figure 1 Page 0 Inventor Takemoto-Nari 292 Yoshida-cho, Totsuka-ku, Yokohama City Hitachi, Ltd. Production Technology Co., Ltd. Inside the research institute

Claims (1)

[Claims] 1. A structure comprising a heating resistor layer and a wiring layer, an adhesive layer that adheres to both layers, and a resistor oxidation-resistant layer and a wear-resistant layer formed on the heating resistor layer. In the heating resistor for a thermal recording head, the outer periphery of the adhesive layer pattern on the upper layer of the lowest heating resistor layer is formed inside the outer periphery of the resistor layer, and the outer periphery of the pattern of the wiring layer on the upper layer of the adhesive layer is formed on the inner periphery of the adhesive layer. 1. A heating resistor for a thermal recording head, characterized by having a structure in which the inside of the body is shaped like ゎ. 2. A heating resistor for a thermal recording head having a structure including a heating resistor and a wiring layer, an adhesive layer that adheres both layers, and a resistor oxidation-resistant layer and a wear-resistant layer formed on the upper layer of the heating resistor. A manufacturing method in which a body is manufactured using a photoetching method, and the etching order is a wiring layer, an adhesive layer, a resistor layer, and an adhesive layer. By placing the wiring layers in this order, the outer periphery of the adhesive layer pattern on the upper layer of the lowest heating resistor layer is formed inside the outer periphery of the resistor layer, and the outer periphery of the pattern on the wiring layer on the upper adhesive layer is formed on the inside of the outer periphery of the adhesive layer. A method for manufacturing a heating resistor for a thermal recording head formed inside. 3. The etching order is the wiring layer, the adhesive layer, the resistor layer, the adhesive layer, the wiring, and the layer in the process of forming the wiring part,
3. The method of manufacturing a heat-generating resistor for a thermal recording head according to claim 2, wherein in the step of forming the resistor part, the wiring layer, the adhesive layer, and the wiring layer are formed in this order.