JP3040432B2 - Sputtering target - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a target used for sputtering, which is one means for forming a thin film in a vacuum.

[Conventional technology and its problems]

FIG. 5 is a schematic sectional view of a basic sputtering apparatus used to form a thin film on a substrate in a vacuum.

In the sputtering apparatus (1) shown in the figure, a substrate (4) is held on a ground electrode (3) inside a vacuum chamber (2).
A cathode (5) is arranged facing the ground electrode (3),
A target (6) made of a material to be sputtered is provided thereon.

While evacuating from the exhaust port (7), a discharge gas, for example, argon is introduced from the gas introduction pipe (8) and kept at a constant pressure. When a voltage is applied between both electrodes in such a state, a discharge occurs, and part of the argon gas becomes argon ions (Ar ⁺ ).
By sputtering the target (6), the material M of the target (6) pops out and the substrate (4)
It is formed as a thin film on top.

If a gas that reacts with the material of the target (6) is introduced together with the discharge gas, a film of a reaction product with the target (6) can be obtained.

In the above-described sputtering, a phenomenon occurs in which a predetermined portion on the surface of the target (6) is locally sputtered and consumed. Particularly in magnetron sputtering in which a magnetic field perpendicular to the electric field is applied, the tendency is strong because the sputtering speed is high.

When the material of the target (6) is a metal, it can be said that the used target (6) is recovered, dissolved and reused. However, when the target (6) is a metal compound, particularly in the case of a metal oxide. However, there is a problem that the remaining portion cannot be reused at all and is at most a raw material for a metal, so that the efficiency is extremely low. Therefore, this has caused a high cost.

Also, it is difficult to obtain oxides having a density of 100%, usually 60 to 8
0% are used. The remaining 20 to 40% is a space and therefore contains gas, and the surface area is large so that the amount of adsorbed gas is large. When such a material is used as a target, the material is heated by sputtering, and the released gas comes out into the plasma, so that abnormal discharge occurs and the quality of the obtained thin film deteriorates. This lowers the yield of thin films and leads to higher product costs.

[Problems to be solved by the invention]

The present invention has been made in view of the above problems, and has as its object to provide an inexpensive sputtering target that emits less gas.

[Means for solving the problem]

The above object, in a sputtering target for sputtering a metal compound, comprising a portion of the metal compound of intense wear, the other portion is composed of a metal of the composition of the metal compound, prior to the sputtering, A sputtering target characterized in that a thin film of the metal compound is formed on the metal by pre-sputtering in an atmosphere of a gas containing a reactive gas.

[Action]

In the sputtering target configured as described above, only the highly consumed portion is made of a metal compound, so that the cost of the target itself can be reduced, and the amount of released gas is reduced, so that a good-quality thin film can be produced with a high yield. Obtainable.

Also, during sputtering, argon ions sputter where the target is likely to be sputtered, so if the target is intensely depleted with a metal compound and the other portions are simply composed of a metal, a metal with a low electrical resistance can be used. Although a part is sputtered, the surface is made uniform by forming a thin film of a metal compound on the surface of the metal in advance, and the argon ion sputters the place where it should be sputtered (the place where the exhaustion is severe). I will be. Further, since the thin film of the metal compound is formed by pre-sputtering in an atmosphere of a gas containing a reactive gas, the metal compound becomes dense and contains a small amount of gas, so that the amount of gas released by heating during sputtering is small. .

〔Example〕

 Next, embodiments will be described with reference to the drawings.

FIG. 1A shows a plan view of the target (9) of the first embodiment. Intense part of the indicated portion depleted by diagonal lines, the metal compound in the present embodiment a sintered body of indium oxide and tin oxide as the _{(10) (I n2 O 3} + 5% S n O 2, density 80%) using Was configured. Part shown by other one-dot chain line is formed by using a metal (11) indium and tin alloy _{(I n + 10% S n} ) as a. 1B, 1C, and 1D are cross-sectional views taken along lines BB, CC, and DD of FIG. 1A, respectively.

This target (9) was set in the sputtering apparatus (13) shown in FIG. The sputter device (13) uses the target (9) in place of the target (6) of the sputter device (1) in FIG. 5, and only the shutter (14) is attached. And description thereof is omitted.

The target (9) is set on the cathode (5) of the sputtering device (13), exhausted from the exhaust port (7), and mixed with argon (Ar) and oxygen (O ₂ ) from the gas introduction pipe (8). Gas was introduced and maintained at 3 × 10 ⁻³ Torr. The shutter (14) is closed so that the sputtered material (M ') of the target (9) does not fly toward the substrate (4), and a voltage is applied between the two electrodes to set the power (power) to a predetermined value. Pre-sputtering (pre-sputtering) was performed for 30 minutes by gradually raising the film at regular intervals until the film was formed.

During this press pad, an oxide film of indium and tin, which is a metal compound film (12), was formed on the surface of the metal (11) portion of the target (9). FIG. 3 is a sectional view schematically showing this state. In the figure, a metal oxide film (12) is formed on the surface of the metal (11), and the surface material is uniform. This metal oxide film (12) was dense.

Then performs original sputtering open the shutter (14), to form a thin film of _{I n2 O 3 + 5% S} n O 2 on the substrate (4). The material of the substrate (4) is quartz glass.

For comparison, a thin film was formed on a substrate in a conventional manner by _{I n2 O 3 + 5% S} n O 2 only configured the same conditions as the embodiment using a target. Pre-sputtering was performed similarly.

The pre-sputtering was performed for the case where the target (9) of the present embodiment was used and the case where the target of the conventional method was used.
The following table shows the results of examining the sputter toilet (film forming speed), the light transmittance and the electric resistance value of the formed film, and the number of abnormal discharges in the main sputtering after 30 minutes.

As shown in the table, the transmittance of light with a wavelength of 550 nm is 90%
Both are the same, but by using the target (9) of the present embodiment, a thin film is formed at a higher speed than in the prior art, and a film having a low electric resistance and a good quality as a transparent conductive film can be obtained. Was.

Also, the number of abnormal discharges generated during sputtering is very small. This is because, in the target (9) of the present embodiment, the metal oxide (10) containing a large amount of gas occupies only about 50% of the whole of the target (9), and the gas which is heated and released by sputtering is correspondingly provided. Is reduced, and the plasma is stabilized.

In general, the better the cooling effect of the material, the smaller the amount of outgassing gas. However, the metal (11) has a better cooling effect because it has better heat conduction than the metal oxide (10). Also in this respect, the amount of released gas is reduced.

In this embodiment, the oxide film (12) is formed on the surface of the metal (11) portion of the target (9) by performing pre-sputtering while introducing oxygen as a reactive gas. In the case where the oxide film (12) is formed by sputtering or the case where the oxide is sprayed by thermal spraying, the amount of released gas is slightly larger than that of the oxide film (12) formed by the pre-sputtering of this embodiment. The method used in this example is optimal.

Since the target (9) of this embodiment has a simple structure, it is easy to combine the metal oxide (10) portion and the metal (11) portion, and it is easy to separate them after use. In the case of the present example, a metal oxide (10) formed in a predetermined shape was put in a frame, and the melted metal was poured around the frame.

 Next, a second embodiment will be described.

Sintered body and oxide-tin oxide-cadmium _{(S n O 2 + 10%} CdO, density 60%) was used as the metal compound (10), metal (1
1) as the target (9 constituted with tin and cadmium alloy _{(S n + 10% Cd)} ) than all of the first embodiment is the same condition. It was possible to form a high-quality transparent conductive film S _n O ₂ + 10% CdO onto the substrate (4).

In the third embodiment, the metal compound sintered body of zinc oxide and manganese oxide as a _{(10) (Z n O +} 0.5% M n O, density 60%)
The used, an alloy of zinc and manganese as the metal (11) (Z _n
A thin film was formed under the same conditions as in the first embodiment, except that the target (9) was formed using (+ 0.5% _Mn ). On the substrate (4) could be obtained a high-quality phosphor film of _{Z n O + 0.5% M n} O.

In the fourth embodiment, an alloy of bismuth, lead, strontium, calcium and copper (Bi-Pb-Sr-Ca) is used as the metal (11).
-Cu) and the same conditions as in the first example except for a target (9) constituted by using an oxide of the same alloy (Bi-Pb-Sr-Ca-Cu-O) as the metal compound (10). To form a thin film. A good high-temperature superconducting film of Bi-Pb-Sr-Ca-Cu-O was obtained on the substrate (4).

In each of the above embodiments, as in the case of the first embodiment, a thin film of higher quality could be obtained as compared with the case where a target composed only of a conventional metal compound was used.

As described above, each embodiment of the present invention has been described.
The present invention is not limited to these, and various modifications are possible based on the technical idea of the present invention.

For example, the target (9) in each embodiment is a rectangular type, and the metal compound (10) is a rectangular ring, but various shapes can be used as needed. For example, the entire target (9) may be disc-shaped, and the metal compound (10) may be formed in a donut shape depending on the portion of heavy consumption, or may be formed in a circular shape at the center.

In each example, the metal compound (1
Although oxide was used as 0), nitride, fluoride, chloride or boride may be used instead. In that case, a gas containing nitrogen, fluorine, chlorine, or boron instead of oxygen is introduced as a reaction gas.

In addition, the target is replaced with the fourth one instead of the configuration shown in FIG. 1A.
It may be configured as shown in the figure. That is, the metal compound is formed by dividing into (10a), (10b), (10c) and (10d) portions, and the metal also forms two portions of (11a) and (11b),
The target (9A) is configured by combining them.

In this case, the metal compounds (10a) (10b) (10
c) (10d) and metal (11a) (11b) that can be easily separated from metal (11a) (11b)
The part is more efficient because it can be used multiple times.

It goes without saying that the target (9A) having this configuration can be used not only in the first embodiment but also in the other second to fourth embodiments.

〔The invention's effect〕

Since the sputtering target of the present invention has the above-described structure, the cost of the target itself can be reduced, and a high-quality thin film can be obtained because the amount of released gas is small, so that the yield increases. There is an effect that the cost can be reduced.

[Brief description of the drawings]

FIG. 1A is a plan view showing a target according to the first embodiment of the present invention, and FIGS. 1B, 1C and 1D respectively show lines BB, CC and DD of FIG. 1A. FIG. 2 is a schematic sectional view showing a sputtering apparatus using the target of the first embodiment, FIG. 3 is a sectional view showing the target of the first embodiment after pre-sputtering, and FIG. FIG. 5 is a plan view showing another configuration example of the target, and FIG. 5 is a schematic sectional view showing a sputtering apparatus using a conventional target. In the figure, (9) (9A) ... target (10) ... metal compound (11) ... metal (12) ... metal compound film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 14/00-14/58

Claims (3)

(57) [Claims] In a sputtering target for sputtering a metal compound, a heavily depleted portion is composed of the metal compound, and another portion is composed of a metal having the composition of the metal compound. A sputtering target characterized in that a thin film of the metal compound is formed on the metal by pre-sputtering in an atmosphere of a gas containing a reactive gas. 2. The method according to claim 1, wherein the metal compound is a metal oxide, and prior to sputtering, a thin film of the metal oxide is formed on the metal by pre-sputtering in an atmosphere of a gas containing oxygen. The sputtering target according to 1). 3. The atmosphere of a gas containing any of nitrogen, fluorine, chlorine and boron prior to sputtering, wherein the metal compound is one of a metal nitride, a metal fluoride, a metal chloride and a metal boride. The sputtering target according to claim 1, wherein a thin film of the metal compound is formed on the metal by performing preliminary sputtering in the inside.