JPH0219961B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a resistive film target.

There are various facsimile reception and recording methods, but electrostatic recording, thermal recording, inkjet recording, etc. are considered promising when considering future prospects. Among these, the fixed scanning multi-element thermal recording method was developed as a printer technology, and has attracted attention as a new recording method because it does not require processes such as developing and fixing, and does not generate odor gas like discharge breakdown recording. ing.

By the way, there are three types of thermal recording heads: thin-film type, thick-film type, and semiconductor type, and the thin-film type has advantages such as good thermal response and high heat resistance of the film.This thin-film type thermal recording head is the most popular. It is constructed as shown in cross section in Figure 1. The heat-sensitive recording head is formed by forming a heating resistor 3 on a ceramic substrate 1 by vacuum evaporation via a heat insulating layer 2, and then forming it into a desired shape by photoetching. Next, a lead wire 4 is provided, and a resistive protective film 5 and an abrasion resistant layer 6 are further provided.
A thin film type thermal head is manufactured by sequentially providing the following.

Here, the heating resistor 3 is formed on the heat insulating layer 2 of the ceramic substrate 1 by sputtering. As for the target used in this sputtering, a target using tantalum (Ta) and silicon oxide (SiO ₂ ) as a thin film resistor has been proposed (Japanese Patent Application No. 1983).
−85008). This allows the specific resistance to be freely selected by mixing SiO ₂ into the Ta thin film to increase the specific resistance and controlling the amount of SiO ₂ . The shape and film thickness can be freely selected depending on the dot size and power density.

Since this heating resistor is made of two elements,
Fluctuations due to manufacturing conditions are within a controllable range. As shown in FIG. 2, the sputter target used is a SiO ₂ plate 21 covered with Ta foil 22. 23 is a metal jig for cooling, 24
is a packing, and 25 is a support stand.

However, this conventional technique also has the following drawbacks.

(1) Although the target surface is formed so that the Ta surface and the SiO ₂ surface are made as small a unit as possible, since the unit is still a fairly large area, only the Ta surface can be seen from the Ta surface. _SiO2
Since only Si--O is ejected from the surface, the distribution of sputtering ions becomes uneven, and this influence cannot be avoided on the attached film, resulting in insufficient microuniformity of the distribution of Ta and SiO ₂ . For this reason, it is unsuitable for use as a constant voltage application type, high-speed heat-generating, low-resistance material, and has poor uniformity, resulting in the occasional occurrence of dots that break down in a short period of time.

(2) Ta foil had a higher spatter rate, so it ran out faster and had a shorter lifespan. In particular, the electric field was concentrated at the edges, corners, and protrusions, causing the Ta foil to wear out more quickly.

(3) For the above reasons, the ratio of Ta and SiO ₂ varies both two-dimensionally and three-dimensionally, making it difficult to control and making it difficult to obtain a uniform, high-quality thin film resistor.

In order to further improve this technique, a target was devised in which tantalum metal (Ta) and silicon dioxide (SiO ₂ ) powder were mixed in an appropriate ratio and then sintered using a hot press method. According to this target, the thin film obtained by sputtering is relatively uniform and a stable resistance value can be obtained. However, these advantages are only realized when the density, chemical components, constituent phases, etc. of the target itself are extremely small in distribution. However, this sintered target is normally manufactured by the hot press sintering method as described above. The shape of a practical target is generally thinner (5 mm) than its area (400 mm vertically x 100 mm horizontally).
When such a shape is sintered using the hot press method,
It becomes very difficult to apply exactly the same pressure to the entire surface of the sintered body, and as a result, it is difficult to produce a uniform sintered body. This is an unavoidable problem due to the shape of the sintered body and the manufacturing method that uses SiO ₂ and Ta as starting materials. Furthermore _, Ta and SiO ₂ are relatively easy to phase react with each other, and the density distribution in _each part of the sintered body is directly related to its constituent _phases .
Various intermediate compounds such as αTa ₂ O ₅ and βTa ₂ O ₅ are generated depending on the pressurized state. With such a target, the inherent advantages of a sintered target are difficult to exhibit, and sophisticated control of sputtering conditions is required to produce a film with good properties.

The present invention has been made in view of this point.
In particular, the method for producing the target is characterized in that the target itself has a uniform constituent phase.

In other words, it is characterized in that TaSi ₂ , the constituent phase of the target obtained by hot-press sintering SiO ₂ and Ta, is used as the starting material from the beginning. As for the manufacturing method
TaSi ₂ powder and SiO ₂ powder are mixed, then formed into a desired shape and sintered by hot pressing or pressureless sintering in a non-oxidizing atmosphere. The reason for mixing SiO ₂ powder is TaSi ₂
If the target is sintered alone, it is difficult to obtain the desired resistance value of the thin film obtained by sputtering. Therefore, in order to control the resistance value of the thin film, an appropriate amount of
Add _SiO2 . Targets manufactured using this method have raw materials TaSi ₂ and SiO ₂ that are used during the manufacturing process.
Because it is close to the state of the final constituent phase produced by reacting Ta and SiO ₂ , there is no intermediate product between Ta and SiO ₂ produced during sintering, and there is almost no phase reaction, resulting in an extremely uniform constituent phase. Target is obtained. The thin film produced by sputtering using this target has film properties such as resistance and film thickness that are essentially the same as those obtained from targets manufactured using SiO ₂ and Ta as raw materials, but there is no variation in the constituent phases. It showed very good results with high yield.

Here, the blending ratio of TaSi ₂ and SiO ₂ is 80 to 99% by weight
A range of TaSi ₂ and 20 to 1% by weight SiO ₂ is substantially preferred; if SiO ₂ exceeds 20% by weight, the reaction becomes complicated and it is difficult to obtain the desired composition (TaSi ₂ ). Also 1
If the amount is less than % by weight, it is difficult to adjust the thin film resistance value.

The present invention will be explained below with reference to Examples.

Example 1 950 g (95% by weight) of tantalum disilicide (TaSi ₂ ) powder with an average particle size of 4.5 μm and 50 g (5% by weight) of silicon dioxide (SiO ₂ ) powder with an average particle size of 1.2 μm were placed in a synthetic resin pot or ball. The mixture was mixed for 15 hours. This mixed powder was cold-formed into a size of 140 mm x 10 mm, and then hot-press sintered in an argon atmosphere at 1400°C, 1 hour, and 200 kg/cm ³ . The porosity of the obtained sintered target was 14%, and the constituent phases of each part of the sintered body were mainly
It consisted of TaSi ₂ . When this target was used in a sputter, a good thin film was obtained.

Example 2 2 tons of mixed powder having the same composition as Example 1
It was cold-formed to a size of 140 mm □ × 10 mm under a pressure of cm ² , and then sintered under normal pressure at 1600° C. for 5 hours in an argon atmosphere. The porosity of the obtained sintered target was 29%, and the constituent phases of each part of the sintered body were mainly composed of _TaSi2 .
When this target was used in a sputter, good results were obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the structure of a thin film thermal head, and FIG. 2 is a perspective view showing a conventional example of a sputter target. 1... Ceramic substrate, 2... Heat insulation layer, 3...
Heat generating resistor, 4...Lead wire, 5...Resistor protective film, 6...Abrasion resistant layer.

Claims (1)

[Claims] 1. A method for producing a resistive film target in which a heating resistor thin film is formed by sputtering a target containing tantalum, silicon, and oxygen in an argon gas atmosphere, wherein the target contains 80 to 90%
A product for resistive film characterized by sintering a mixed powder of tantalum disilicide (TaSi ₂ ) at % by weight and silicon dioxide (SiO ₂ ) by 20-1% by weight at a temperature of 1100-1600°C in a non-oxidizing atmosphere. Target manufacturing method.