JP2917744B2 - Si target material for magnetron sputtering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Si target material for magnetron sputtering capable of forming a film with few particles for a long period of time.

[0002]

Conventionally, in general, to generate a plasma using a reactive gas such as N ₂ or O ₂ as an atmosphere gas, while applying a magnetic field in the direction perpendicular to the surface of the Si target material by the magnet, the Si target There is known a magnetron sputtering method in which a material surface is sputtered to form a SiN film or the like on the surface of a substrate.

[0003]

On the other hand, the size and performance of this type of magnetron sputtering apparatus have been remarkable in recent years, and the sputtering conditions accompanying this have become more severe. In the case of a material, especially when sputtering under severe conditions, a large number of coarse particles having a diameter of 0.3 μm or more are generally generated during film formation in a relatively short operation, and the service life is shortened. At present.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the viewpoints described above, studies were conducted to develop a Si target material for magnetron sputtering that does not generate coarse particles during film formation. (A) In the case of a conventional Si target material, it can be formed in a relatively short time. A large number of particles are formed in the film because a sputter product such as SiN is deposited on the non-erosion portion of the sputter surface of the target material during operation, that is, on the central portion and the outer peripheral edge of the sputter surface. When the amount of the deposit reaches a certain amount, the deposit separates from the non-erosion portion during sputtering, and this is mixed as particles during film formation.

(B) In general, in the conventional Si target material, the surface roughness of the sputtering surface is set to 0.1% over the entire surface.
02 to 0.1 μm Ra (center line average roughness, the same applies hereinafter). The surface roughness of the non-erosion portion on the sputter surface is set to 0.2 to 2 μm Ra, which is relatively coarse, and the remaining planar ring shape is used. When the surface roughness of the erosion portion is set to 0.01 to 0.05 μm Ra, which is smoother than this, the sputter is smoothly performed by the surface roughness of the erosion portion and the generation of a large number of particles is performed in a state where it is suppressed as much as possible. On the other hand, since a strong adhesion is formed between the sputter products deposited during operation due to the relatively rough surface roughness of the non-erosion portion,
Even when sputtering is performed under severe conditions, the sputtered deposits do not peel off from the non-erosion portion, and the formation of particles during film formation is suppressed for a long time. The research results shown in (a) and (b) above were obtained.

The present invention has been made on the basis of the above research results, and has a flat ring-shaped erosion portion on the sputtered surface with a surface roughness of 0.01 to 0.05 μm Ra.
And the surface roughness of the non-erosion portion composed of the central portion and the outer peripheral portion of the remaining sputtered surface is 0.2 to 2 μmR.
By setting a, the characteristic of the Si target material for magnetron sputtering that enables formation of a film with few particles over a long period of time.

Next, the reason why the surface roughness of the eroded portion and the non-eroded portion in the Si target material of the present invention is limited as described above will be described. That is,
The surface roughness of the erosion part is 0.01 to 0.05 μmR
If the surface roughness is less than 0.01 μm Ra, the sputtered surface is too smooth, and spattering is not particularly smoothly performed in the initial stage.
If it exceeds 5 μmRa, abnormal discharge is likely to occur, which causes a large number of particles. Further, the surface roughness of the non-erosion portion is set to 0.2 to 2 μm.
If the surface roughness is less than 0.2 μmRa, a strong adhesion force without delamination during sputtering cannot be formed between the sputtered product and the sputtered product. Separation of the sediment occurs to cause a large number of particles, while the surface roughness is 2 μm
Above Ra, abnormal discharge is likely to occur due to the rough surface, particularly at the beginning of sputtering, and the number of particles during film formation also increases. It is desirable that the corner of the sputtered surface be an R-processed surface in order to prevent abnormal discharge.

[0008]

Next, the Si target material of the present invention will be described with reference to examples. Each of the Si target materials 1 to 2 of the present invention, each having a sputtered surface roughness shown in Table 1 and having a diameter of 250 mm × thickness: 10 mm, has a circular shape.
3 and conventional Si target materials 1 to 3 were prepared. Next, using the various Si target materials obtained as described above, a DC magnetron sputtering device was used to apply a voltage:
Under the conditions of 400 V, output: 800 W, atmosphere: Ar of 1 × 10 ⁻⁴ torr, an operation of forming a 0.1 μm Si film on the surface of a flat circular Si wafer having a diameter of 150 mm was repeatedly performed. Using a particle counter to determine the number of particles having a diameter of 0.3 μm or more in the film,
Observation was performed by irradiating a laser beam, and the number of Si wafers was measured until 100 or more particles existed during the film formation. Table 1 shows the results of these measurements.

[0009]

[Table 1]

[0010]

According to the results shown in Table 1, the erosion portion of each of the Si target materials 1 to 3 of the present invention is the same as the conventional surface roughness in terms of the sputtering efficiency. By relatively roughening the surface roughness of the central portion and the outer peripheral portion of the surface, the adhesion to the sputter products deposited on the surface is high, so that the sputter products are peeled during the sputtering. As a result, the generation of particles during film formation is significantly suppressed over a long period of time, whereas the conventional Si target materials 1 to 3 have the same surface roughness of the sputtering surface. The surface roughness is mainly based on the sputter efficiency, and must be relatively smooth by all means.As a result, spatter is generated especially in spatter under severe conditions. Can not be avoided the peeling from the sputtering surface of the product material, it is clear that so view particles frequently in a short time of operation. As described above, the Si target material of the present invention can suppress the occurrence of a large number of particles during film formation over a long period of time even under sputtering under severe conditions. It can respond satisfactorily to chemical conversion and shows a long service life.

Claims (2)

(57) [Claims] 1. A flat ring-shaped erosion portion of a sputtered surface has a surface roughness of 0.01 to 0.05 μm Ra (center line average roughness), and is constituted by a central portion and an outer peripheral edge portion of the remaining sputtered surface. Surface roughness of non-erosion part is 0.2
An Si target material for magnetron sputtering, wherein the Si target material has a thickness of 2 μmRa. 2. The method according to claim 1, wherein a corner of an outer peripheral edge of the non-erosion portion is an R-processed surface.
The Si target material for magnetron sputtering as described above.