JPH02153752A - Thin-film type thermal head and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a protecting film having good abrasion resistance and heat conductivity by forming an abrasion-resistant layer in two-layered structure of SiOxNy for a flower layer and SiCz for an upper layer (x,y and z represent the ratio of a component, x=0, y=0 and z=0). CONSTITUTION:An SiOxNy film 5 as a lower layer is formed through plasma CVD process using SiH4, N2, N2O and O2 as material gases. If NH3 is contained in the material gas, the containing amount of hydrogen in the film is increased. Therefore, from the viewpoint of heat-proof property, it is preferable that the material gas contains little NH3. It is necessary to throw-in a large quantity of electric power to dissolve the N2. An upper layer 6 is formed of SiCz through plasma CVD process using SiH4, CH4, C2H4 and C2H2. A gas containing less CH group in CH4, C2H4 and C2H2 is more desirable from the viewpoint of heat-proof property. The temperature of a substrate should be 300 deg.C or higher. Even when N2O or O2 is not added, if a large quantity of power is thrown-in, nitrogen ions or radicals of high exciting property are produced. Accordingly, the hydrogen in the film can be reduced by the hydrogen separation reaction between the nitrogen ions or radicals and Si-Hn. As a result, a protecting film having good abrasion resistance and thermal conductivity is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thin-film thermal head and a method for manufacturing the same, and more particularly to the structure of a wear-resistant coating that protects a heating element. .

Conventional technology Conventionally, thin-film thermal heads use tantalum oxide (Ta2es) p silicon nitride (SiNy) on metal electrodes and heating elements.
, silicon carbide (SiCz), SiCzNy, or the like is formed by sputtering or plasma CVD.

Problems to be Solved by the Invention The following requirements are required for the wear-resistant film of a thin film type thermal head. (1) High hardness and little wear of the film due to friction with paper. (2) Even if continuous printing pulses are applied to the heating element, the wear-resistant film will not be destroyed by thermal stress. (3) The wear-resistant film has good adhesion at the interface with the electrode layer 9 and the heating element layer. (4) Even if the heating element is heated to a high temperature, the structure of the protective film does not change and is thermally stable. (5) Good productivity.

However, the hardness of the film made of tantalum oxide (Ta2O6) is small (the amount of wear is large), so the film thickness must be reduced (
Both had the problem of having to be 6 μm or more. A film made of silicon nitride (SiNy) has a high hardness (it is chemically stable, but its thermal conductivity is not good and the internal stress of the film becomes large. As a result, the wear-resistant film of silicon nitride has a hardness of the printing pulse. There was a problem that it was easy to break due to thermal stress.Also, when silicon nitride and silicon carbide were formed by sputtering, the incident power was increased (which caused abnormal discharge to occur easily on the surface of the target material, and the film deposited at high speed However, there was a problem that defects were easily generated.SiH4tN
Films formed in a mixed gas containing hydrogen groups such as Hse or CH4, C2H4 tend to contain hydrogen bonds (Si-H bonds, etc.), and as this hydrogen leaves the film at high temperatures, the structure of the film changes. Changes occurred, causing cracks, etc. Therefore, there was a problem in heat resistance as an abrasion resistant film. The adhesion at the interface between the wear-resistant film made of silicon carbide, silicon nitride, etc. and the underlying electrode Cu was poor (there was a problem that peeling easily occurred at the interface when a tensile test was performed with tape attached).

The present invention aims to solve these problems.

Means for Solving the Problems In order to solve the above problems, we used 5iOxNY in the lower layer and SiCz in the upper layer (X, Y, Z indicate the component ratio,
≠O, Y≠0, Y≠0, Z≠0), and the lower layer is Cr.

It has been found that the above problem can be solved by forming an electrode consisting of two layers of Cu (or a compound of Cu and Cr) as the upper layer and diffusing Cr into the Cu layer by annealing.

In the present invention, the lower SiOxNy film uses S as a raw material gas.
iH4 (or SiF4, 5iCe4).

N t (or mixed gas of NH3 and N2) * N
It is formed by a plasma CVD method using 2O*02.

Since containing NH3 increases the hydrogen content in the film, a raw material gas containing less NHs is preferable from the viewpoint of heat resistance. Further, as discharge power, it is necessary to input a large power in order to decompose N2. The upper layer silicon nitride (SiCz) is Si
H41CH41C2H4# Formed by plasma CVD using CtH2. Among CH4 and C2H41C2H2, gases with fewer CH groups are more preferable from the viewpoint of heat resistance, and the substrate temperature needs to be 300° C. or higher.

Effects The effects of the present invention produced by using the above-mentioned means are as follows. S in the lower layer of the wear-resistant film of the present invention
iOxNy is a combination of SiH4 and N2 gas with N2O (or 0
By adding 2), internal stress can be controlled and SiH bonds in the formed film can be reduced. This is because a reaction occurs in which hydrogen is taken away from 5i-Hn by oxygen ions and radicals in the plasma. N2O or 0
Even when 2 is not added, in the SiH4-N2 gas system reaction, highly excited nitrogen ions and radicals are generated by injecting high power, and the hydrogen in the film is removed by the hydrogen desorption reaction between these and 5i-Hn. Can be reduced. Also, [S
By keeping the flow rate of N2O (or Ch) constant at 1/10 and adding the flow rate of N2O (or Ch) to about 10% of the flow rate of N2, the deposition rate of the S1oxNy film is 3.
-4 times increase, and the internal stress became larger in compression. Third
As shown in the figure, the greater the compressive stress of the SiOxNy film, the better its longevity against continuous printing pulses. From the above, S
The 1oxNy film has few 5i-H bonds and has good heat resistance, and also reduces internal stress by N2O. By controlling the flow rate of 0.02, the lifetime characteristics of continuous printing pulses of the wear-resistant film can be optimized. On the other hand, the S 1oxNy film is 02 or N2
If the flow rate of O is increased, the hardness will be low due to oxygen richness, and the wear resistance will be inferior. Therefore, by forming SiCz with high hardness (good heat conduction) on the upper layer, wear resistance can be improved.
The thickness of the Z film is at least 1 μm compared to the SiOxNy film.
The film may be as thin as the above and does not need to be deposited at high speed, so it is possible to suppress the inclusion of hydrogen groups (SiH) in the film.

Adhesion was poor at the interface between the silicon carbide, silicon nitride, and SiOxNy films and the electrode Cu, and peeling occurred in the tape tensile test.
In the two-layer electrode structure with Cr as the lower layer and Cu as the upper layer, the annealing treatment had the effect of increasing adhesion strength at the interface with the electrode by diffusing Cr to the surface of the Cu. Further, this effect can also be achieved with an electrode having a compound of Cr and Cu as an upper layer.

Example 1 FIG. 1 shows a sectional view of a thin film type thermal head.

In Figure 1, 1 is a glazed alumina substrate, 2 is an electrode made of a mixture of TiC and SiOx, 3 is a lower electrode made of Cr, and 4 is Cu (or a compound of Cu and Cr).
5 is a lower wear-resistant film made of SiOxNy, and 6 is an upper wear-resistant film made of SiCz.

Example 2 FIG. 2 shows the dependence of internal stress and Vickers hardness on the [N2O]/[N2] flow rate of a film formed in a S r H4, N 2 O T N 2 mixed gas.

In this case, [S i N4] = 40 sec[N2]
=400.8. ,,substrate temperature 350℃, atmospheric pressure 1.0T
The film was formed at orr+incident power=500W. Figure 3 shows [N
It shows the relationship between the destructive life of continuous printing pulses and printing power with respect to the 2O1/[N2] flow rate ratio. The number of pulse lifetimes is printing time 1, O1lsec + period 2O
s+sec reduces printing power per dot from 0.9 to 1
．． It shows the number of pulse lifetimes when changing to 2W. When the flow rate ratio [N2O]/[N2] was changed from 0 to 1710, the internal stress of the membrane changed from tensile to compressive, and the Vickers hardness changed from 1800 to 1400. In addition, the pulse life characteristics are [N2O] /
SiOxNy with a large [N2] ratio was good. The refractive index then changed from 2.1 to 1.7. That is, as the number of 5i-0 bonds increases in the structure of the SiOxNy film, the cracking resistance against continuous pulses improves, but the hardness decreases and the wear resistance deteriorates. Therefore, by forming SiCz, which has high hardness (and good thermal conductivity), on the SiOxNy protective film, SiO2, which has good crack resistance due to its two-layer film structure,
A wear-resistant film having xNy and characteristics of a SiCz film with good wear resistance was obtained. In addition, as this SiCz film, [C
2H4] = 50mccs* [S i N4] =
30 mccII e Substrate temperature 400℃, atmospheric pressure 1.0T
The film formed with orr+incident power of 30W has a Vickers hardness of 1900 and SiH absorption (2
100 cm-'), and the heat resistance was good even after annealing at 500°C.

Effect of the invention The effects of the present invention are as follows.

First, the first effect is that by using SiCz as the upper layer of the wear-resistant film, a protective film with good wear resistance and thermal conductivity can be obtained.

The second effect is that the lower layer of the wear-resistant film, SiOxNy, contains N2O. By adding 02, the hydrogen content can be reduced, internal stress can be optimized, and heat resistance and life characteristics against continuous applied pulses can be improved. Also, productivity increases significantly.

The third effect is that the electrode has a two-layer structure with Cr as the lower layer and Cu or a compound of Cu and Cr as the upper layer, and the adhesion at the interface between the electrode and the SiOxNy film is improved by annealing.

The fourth effect is that N is used as the raw material gas for the SiOxNy film.
2, highly excited nitrogen radicals and ions, and SiH
The reaction of n produced a film with less hydrogen and good heat resistance.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a thin film thermal head according to an embodiment of the present invention, and FIG. 2 is a diagram showing internal stress and Vickers hardness of the wear-resistant film according to an embodiment of the present invention with respect to the flow rate ratio of [N2O]/[Ntl. FIG. 3 is a diagram showing the dependence of [N2O]/[N
FIG. 3 is a diagram showing pulse life characteristics with respect to the flow rate ratio of tl. 1... Glazed alumina substrate, 2...
・Heating element layer, 3...Lower electrode (Cr), 4...
... Upper layer electrode [Cu (or Cu/Cr) 1.5
...Lower wear-resistant film (S i 0xNy), 6
・・・・・・Upper layer wear-resistant film (SjCz) Name of agent Patent attorney Shigetaka Awano and 1 others 1 Fig. 1 (Cr) 4-Upper layer 9-electronic name (CuLar Ca/Cr)s--Lower layer'"tJ! n FIN C3rOxNy) 7- layer q'ft ding N wear R (s; cz) Figure Figure C (NzO)/ ("Z) = tO (%) CNzo'+
ICNz〕= q, sm〕ChhO”)/CNz〕=
0 (%) to Rata, l ratio 0.5 l-t) /, 5 Print! + momme [WcoO

Claims (4)

[Claims] (1) Consisting of a substrate, a heating element layer and an electrode layer formed on this substrate, and a wear-resistant film formed on these heating element layer and electrode layer, and the wear-resistant film is a material of the lower layer. SiO
xNy, and the upper layer material is SiCz (X, Y,
1. A thin film type thermal head comprising two layers, where Z indicates a component ratio, where X≠0, Y≠0, and Z≠0. (2) The material of the upper layer of the heating element layer is Cu or Cu and C.
It is formed of a two-layer heating element with a compound of
Alternatively, the thin film type thermal head according to claim 1, wherein the annealing treatment is performed in a vacuum. (3) Consisting of a substrate, a heating element layer and an electrode layer formed on this substrate, and an abrasion-resistant film layer formed on these heating element layer and electrode layer, and the abrasion-resistant film is a material of the lower layer. SiO
xNy, and the upper layer material is SiCz (X, Y, Z
indicates the component ratio, X=0, Y≠0, Z≠0), and the wear-resistant film is coated with plasma C.
A method for manufacturing a thin film thermal head, characterized in that it is formed by a VD method. (4) As a raw material gas for forming the SiOxYn film, Si
H_4 (or SiF_4, SiCl_4), N_2
(or mixed gas of NH_3 and N_2), N_2O(
Alternatively, SiH_4 (or SiF_4, SiCl_4) is used as the raw material gas to form the SiC_2 film.
), CH_4 (or C_2H_4, C_2H_2)
A method for manufacturing a thin film thermal head according to claim 3, characterized in that the method uses: