JPH0285360A - Multiple target for sputtering - Google Patents

Abstract

PURPOSE:To form an embedded-type multiple target improved in the prolongation of service life by filling plural blind holes formed in a target plate with powdered filling material having a composition dissimilar to that of the target plate and increased in sputtering speed. CONSTITUTION:A target plate 31 (e.g., SiO2 plate) is formed on a backing plate 33, and plural circular holes are formed at equal spaces apart in the above target plate 31 until they reach the backing plate 33. Subsequently, powdered filling material (e.g., Tb powder) 32 having a sputtering speed higher than that of the target plate 31 and also having a composition dissimilar to that of the target plate 31 is filled into the above holes, by which a multiple target is formed. Sputtering is carried out by using the above multiple target, and, when differences in level begin to appear in the boundary zones between the target plate 31 and the filling material 32, a new portion of the above powdered filling material is added to the above holes to regulate the levels of the filling material 32 so that they are equal to the level of the target 31. By this method, a fixed intensity ratio between Tb and SiO2 can be maintained until the target plate 31 becomes unusable, by which the service life of the target can be prolonged.

Description

[Detailed Description of the Invention] [Summary] The purpose of the present invention is to provide a composite target for sputtering, which is an embedded type composite target that has been improved so as to have a longer service life. A composite target comprising a target plate consisting of: and is configured to be in powder form.

[Industrial application field]

The present invention relates to targets, and more particularly to composite targets for sputtering.

Composite targets are used to form alloy films and thick gold-doped dielectric films by combining different metals and inorganic compounds such as oxides.

[Conventional technology]

As a composite target, as shown in Fig. 4, there is an overlay type in which chips (small pieces) 2 of different components are arranged on a single target plate 1 and a predetermined composition is obtained by changing the area of the chips. There are multiple targets. A backing plate 3 is provided behind the target plate l for reinforcement. For example, 5 such additional compound targets
When forming (depositing) a Tb-containing 5i02 film by sputtering an IoT target plate and a Tb chip placed thereon, the intensity ratio of Tb and Sin ( Tb/SiO□) decreases significantly as the cumulative sputtering time increases. This means a change in the composition of the formed film.

Therefore, in order to reduce such compositional fluctuations, the sixth
As shown in the figure, a plurality of holes are made in the target plate 21,
An embedded composite target in which a chip 22 of a different type of component is embedded (inserted) has been proposed. In this case as well, there is a backing plate 23 behind the target plate 21, which serves as the bottom of the hole. When sputtering is performed using the above-mentioned material to form a composite target with the 5iOz target plate 21 and the embedded Tb chip 23, the decrease in the Tb/Sing intensity ratio is significantly improved, as shown in FIG. becomes smaller.

[Problem to be solved by the invention]

Although the embedded type composite target has an improved reduction rate (compositional fluctuation) compared to the overlay type target, the Tb/SiO□ intensity ratio still decreases as shown in FIG.

Since the Tb sputter rate is too large than the 5iO1 sputter rate, a step is created at the boundary between the target plate and the embedded chip, and if sputtering is continued, some of the metal Tb chips disappear and the backing plate below It will come out. For this reason, the target life was about 100 hours, although it also depended on the thickness of the chip. Therefore, from the viewpoint of target life, even an embedded composite target in which a chip (small piece) is embedded is insufficient.

It is an object of the present invention to provide an improved implantable composite target that has a longer service life.

[Means to solve the problem]

The above-mentioned object is a composite target consisting of a target plate made of a part of the composition of the film to be formed by sputtering, and embeddings made of other ingredients embedded in a plurality of blind holes provided in the target plate. ,
The embedding is achieved by a sputtering composite target which has a faster sputtering rate than the target plate and is powder-like.

[For production]

With the use of a composite target for sputtering (increasing the cumulative sputtering time), the embedded material decreases faster, creating a step at the boundary between the target plate and the powder embedded material, and the Tb/SiO□ intensity ratio becomes continuous. decreases to

In order to prevent this drop, if a step starts to appear, add new powder to make the height of the embedding the same as the target plate and eliminate the step.
This returns the SiO□ intensity ratio to its initial state. In this way, the target plate can be sputtered and used as a target until it reaches its service limit, and the sputtered state of the implant does not define the target life.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail by way of embodiments with reference to the accompanying drawings.

FIGS. 1A and 1B show a sputtering composite according to the present invention.
FIG. 2 is a plan view and a cross-sectional view of a combined target.

The composite target according to the present invention includes, for example, a SiO□ target plate 31 (thickness: 4 m) and a backing plate 33.
(diameter 5 inches), and drilled a plurality (8) holes (diameter 10 m) in the target plate 31 in a circular shape and at equal intervals until reaching the backing plate 33, and then (particle size 20Is) 32 to the same level as the target plate 31 (filling).

The prepared target was used in a magnetron sputtering apparatus using argon gas, and the Tb/5ift intensity ratio of the formed Tb-containing SiO2 film was examined, and the results shown in FIG. 2 were obtained. When the cumulative sputtering time is up to 6 hours, the Tb/5iOz intensity ratio decreases only slightly, but the sputtering rate (decrease) of the Tb powder embedding 32 is Sin, and the sputtering rate (decrease) of the target plate 31 is
: $i small), so there is a step at the boundary (about 100 Ins step) so that a recess is created in the hole.

Then, every 6 hours of cumulative sputtering time, Tb
Add powder to increase the height of the implant to 5in2
Use the same target plate and perform sputtering under the same conditions. As a result of sputtering, the thickness of the SiO□ target plate 31 gradually decreases, and finally the S
A part of the iO□ target plate 31 completely disappears, exposing the underlying backing plate 33. Until the end of the target life of this backing plate surface, Tb/
The SiO□ intensity ratio was examined and the results shown in FIG. 3 were obtained, and the target life in this case was about 1600 hours. 7th
As can be seen from the figure, the Tb/Sing intensity ratio is almost constant and the target life is defined by the 5iOz target plate, making it possible to achieve a much longer life than before.

In the above explanation, Tb was used for the embedding material, but Gd
, Dy, Nd, Pr and other rare earth metals, Ti
, Zr, PL, AI, etc. can also be used, and the target plate niha5iOt can be replaced with te ZnS, 5t3Na + TiO□, ZrO□
, PBO, or other insulators may also be used.・Out of these, Si3 is a combination of oy and 5iJ4.
Even with a composite target consisting of a N2 target plate and a Dy powder embedded material, a sputtering film with almost the same Tb/SiO strength ratio as described above and a y/5izN4 strength ratio can be formed, and the target life is also longer than before. has also increased significantly.

〔Effect of the invention〕

According to the present invention, a powdered implant is used in place of a conventional chip in an embedded composite target, and the reduction is compensated for by additional powder replenishment to restore the target surface to a flat surface. This allows a constant Tb/
The 5ift intensity ratio can be maintained until the target plate becomes unusable, and the life of the target can be extended. Further, the efficiency of using the target plate is significantly improved, and it is possible to reduce the sputtering film forming cost.

[Brief explanation of drawings]

FIG. 1A is a plan view of a composite target for sputtering according to the present invention, FIG. 1B is a cross-sectional view taken along line IA-IA in FIG. 1A, and FIG. 2 is a diagram showing Tb/Sin, strength, FIG. 3 is a graph showing the relationship between the ratio and the sputtering cumulative time.
FIG. 4 is a graph showing the relationship between iO
/5i(12) This is a graph showing the relationship between the intensity ratio and the sputtering cumulative time. Figure 6 is a schematic cross-sectional view of a conventional chip-embedded composite target. Figure 7 is a graph showing the relationship between the intensity ratio and the sputtering cumulative time. It is a graph showing the relationship between Tb/Sin, intensity ratio, and cumulative sputtering time when 31... 5 inz target plate, 32... Tb powder embedded material, 33... backing plate.

Claims (1)

[Scope of Claims] 1. A target plate made of a part of the composition of a film to be formed by sputtering, and an embedding made of other ingredients of the composition to be embedded in a plurality of blind holes provided in the target plate. A composite target for sputtering, characterized in that the embedded material has a faster sputtering speed than the target plate and is in powder form.