JPH04184732A - Sputtering target and protective film using the sputtering target - Google Patents

Abstract

PURPOSE:To obtain same film characteristics under constant film forming conditions by a method wherein an Al-Si target is manufactured by a cast alloy method. CONSTITUTION:In order to manufacture an Al-Si alloy target, a cast alloy method is employed. First, 70 at.% of Si is put into a crucible and heated to 1500 deg.C in a vacuum melting furnace and then 30 at.% of Al is put into the crucible and Al and Si are naturally mixed under a constant temperature of 1500 deg.C and cast into a mold. At that time, crystal grains are distributed uniformly over the whole surface and, moreover, as the target is made of cast alloy, the density is 100%, which is very convenient for sputtering. With this constitution, the same film characteristics can be obtained under constant film forming conditions and density unevenness and variation can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sputtering target and a thin film formed using the sputtering target.

[Prior art] Aluminum silicon nitride film (hereinafter referred to as Al25iN film), which has been used as a protective film for conventional optical discs, uses a sintered target of Aβ and Si to form an A r + N film.
The film was formed by reactive sputtering.

[Problems to be Solved by the Invention] However, with the sintered target of the prior art described above, the stability of the sintering method is poor, and the density unevenness within the target or between targets is large, and the film is formed by reactive sputtering. In this case, in order to obtain the same film characteristics, it is necessary to change the film forming conditions for each target, and it takes a lot of time to refine the film forming conditions.

Therefore, the present invention is intended to solve such problems, and its purpose is to provide a target with no density unevenness or variation that can obtain the same film characteristics under constant film formation conditions,
Our goal is to provide a protective film with excellent protective performance.

[! l! Means for Solving the Problem] (1) In manufacturing an alloy target of Al2 and Si,
It is characterized by using the casting alloy method.

(2) The composition ratio of l and St is 10≦AJ≦70 at%.

(3) A nitride film is formed by reactive sputtering using the sputtering target described in item 1 or 2.

[Example] To create a cast alloy sputtering target of 70 at% Al230Si, first put Si in a crucible,
Heated to 1500℃ in a vacuum melting furnace, then Al
The amount equivalent to oat% was put into a crucible and allowed to mix naturally at a constant temperature of 1500°C. Then, the metal was poured into the mold. At this time, the mold is water-cooled so that the AlSi alloy is rapidly cooled. This is because rapid cooling reduces the growth of crystal grains and is convenient for sputtering.

The completed ingot was machined to 5 inches in diameter and 6 mm in diameter. FIG. 1 schematically shows the surface state at this time.

As can be seen from this figure, the crystal grains are uniformly dispersed throughout, and since it is a cast alloy, the density is 100%, which is very convenient for sputtering.

This target was attached to a Cu backing plate and a film was formed by sputtering.

A film was formed on a Si wafer for 10 minutes using Ar pressure of 1.7 mTorr, N2 partial pressure of 0.5 mTorr, and RF power of 2.5 KW. The film thickness is 2000, and the film stress is 3. Ox
1 O'dyn/cm", and the film thickness refraction index was 2.Ol. Furthermore, in order to evaluate the film quality of the protective film performance, an etching test using a buffered hydrofluoric acid solution was performed, and the etching time was 85 minutes. In addition to this, A
j230Si 70at% cast alloy target lO
A similar film-forming experiment and evaluation was conducted. The film forming conditions were the same as above, Ar pressure 1.7 mTorr, N* partial pressure 0.
The deposition time was 5 mTorr, RF power 2.5 KW, and 10 minutes.

Table 1 shows the properties of these 10 films.

Table 1 As can be seen from Table 1, when the cast alloy target of the present invention is used, almost the same film properties are obtained under the same film forming conditions.

On the other hand, AJ230Si70at% made by conventional sintering method
We attempted an experiment to evaluate the target.

The sintering target uses powdered Aβ and powdered Si to form Al30Si.
Mix it to 70 at% and use HotPress for 5
A target with an inch diameter of 6 mm was prepared. FIG. 2 schematically shows this surface state. As can be seen from this figure, the surface condition (matte finish) is significantly different and uneven. Create a total of 10 targets,
The film was attached to the Cu backing plate by sputtering.

The film forming conditions were the same as those for the cast alloy target of the present invention described above.
r pressure 1.7 mTorr, N*partial pressure 0.5 mTorr, R
The F power was 2.5 KW and the film forming time was 10 minutes.

Table 2 As can be seen from Table 2, when using a target by the sintering method, under the same film forming conditions.

Large variations in all film properties are observed. This is due to the instability of the sintering process itself, and is due to the variation in surface condition shown in FIG. In other words, in order to obtain the same film characteristics, it is necessary to change the film forming conditions. In addition, it can be seen that the etching test, which is an index of protection performance, is also significantly inferior to that for cast targets.

This time, we investigated the difference by applying it to Al230S i 70at%, but it was found that 10≦AI2 has excellent protection performance.
It was confirmed that cast targets are superior to all targets in the range of ≦70 at%.

This embodiment is particularly effective for protective films for optical disks and passivation films for semiconductors.

[Effects of the Invention] As described above, according to the present invention, the same film characteristics could be obtained under the same film forming conditions by creating an Al2Si target using the casting alloy method. Furthermore, the film has the effect of exhibiting good protective performance.

[Brief explanation of drawings]

Figure 1 shows AJS made by the casting alloy method according to the present invention.
Schematic diagram of the surface state of i-target. FIG. 2 is a schematic diagram of the surface state of an AlSi target produced by a conventional sintering method. Applicant: Seiko Epson Corporation

Claims (3)

[Claims] (1) A sputtering target characterized in that a casting alloy method is used in manufacturing an alloy target of Al and Si. (2) The sputtering target according to claim 1, wherein the composition ratio of Al and Si is 10≦Al≦70 at%. (3) A protective film characterized in that a nitride film is formed by reactive sputtering using the sputtering target according to claim 1 or 2.