JPS6328988B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] By forming the surface of the sputter target to be the same as or higher than the surface side of the shield plate installed around the sputter target, abnormal discharge can be eliminated and the surface of the sputter film can be improved. Improve morphology.

[Industrial application field]

The present invention relates to a sputtering method,
More specifically, we use a target with a shape that prevents deposits on the surface of the shield plate from falling onto the sputter target surface, and also has a homogeneous target material in the area directly below the gap between the edge of the target surface and the shield plate. , relates to an improved sputtering method to prevent the release of contaminating impurity particles.

[Conventional technology]

A sputtering device is used to form a metal thin film on a substrate.

As shown in FIG. 2, this device consists of a vacuum container 1
The substrate 12 is placed on one anode side (anode side) of the opposing electrodes in 1, and the substrate 12 is placed on the other cathode side (cathode side).
A sputter target 13 is placed in the vacuum vessel 11, and atoms of the sputter target 13 are ejected to the outside by ions such as argon supplied into the vacuum vessel 11, and are attached to the surface of the substrate 12 placed on the counter electrode. (deposition).

The details of the cathode side part are as shown in the cross-sectional view of FIG. 3 and the plan view of FIG. 4. An ivy target 13 is arranged and adhered with an adhesive or the like.

The peripheral edge of this sputter target 13 is fixed to a support plate 15 by a presser plate 17 attached with screws 16. In this way, the sputter target 13 is held on the support plate 15 by the holding plate 17.
The reason for fixing the sputter target 13 is, for example, when the sputter target 13 is arranged at an angle in a two- or three-unit type, if it is fixed only with adhesive,
This is to prevent it from slipping off due to heat.

A shield plate 18 made of a material such as stainless steel is provided on the outside of the presser plate 17, screws 16, support plate 15, etc. around the sputter target 13 to prevent spatter from ions such as argon.
covered by.

Note that the target support stand 14 has a shield part 19.
It is electrically insulated from the vacuum vessel 11 and cooled by cooling water supplied from the outside. In addition, the target support stand 14
A high negative voltage is applied to the side.

[Problem that the invention seeks to solve]

However, in sputtering using a sputtering apparatus having such a structure, sputtering material adheres to the peripheral edge of the shield plate 18, and the attached sputtering material peels off during sputtering and falls onto the sputtering target 13. At this time, an abnormal discharge occurs, and the fallen spatter material becomes particles with a size of about 2 to 3 μm or less, and is carried to the surface of the substrate 12 and incorporated into the spatter film (metal thin film) 20, making the surface rough. .

Therefore, as shown in FIG. 5a, the substrate 12
Convex portions 21 are formed on the surface due to adhesion of foreign matter, and as a result, during patterning alignment in the subsequent process, as shown in FIG.
There was a risk that the resist film 22 formed thereon would be carried away by the mask 23, resulting in pattern defects due to resist defects.

The present invention was created in view of these points, and prevents abnormal discharge caused by deposits on the surface of the shield plate 18 falling onto the surface of the sputter target 13, and prevents abnormal discharge caused by the surface morphology of the spatter film 20. The object of the present invention is to provide a sputtering method that can eliminate pattern defects and improve yield.

[Means for solving problems]

FIG. 1 shows a sectional view of a sputter target portion of a sputtering apparatus according to the present invention.

In FIG. 1, 14 is a target support base;
5 is a support plate, 17 is a presser plate, 31 is a sputter target, and 18 is a shield plate.

In the present invention, the surface of the sputter target 31 is projected at the same level as the surface of the shield plate 18 or slightly higher (about a few mm), and the part directly below the gap between the end of the target surface and the shield plate is also of the same quality. Sputtering is performed by forming a target material into a shape.

[Function] It becomes difficult for spatter substances to adhere to the surface of the shield plate 18, and the abnormal discharge that occurs in the past due to falling of adhered substances is eliminated.

Therefore, there are no minute foreign substances that fly to the surface of the substrate 12 and are taken into the sputtered film 20, and the surface morphology of the deposited sputtered thin film improves.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a cathode side portion of a sputtering apparatus according to an embodiment of the present invention.

In this apparatus, as shown in the conventional example shown in FIGS. 2 and 3, a sputter target 31 is placed on the upper surface of a target support base 14 with a support plate 15 interposed therebetween.

This sputter target 31 is formed into a substantially disc-shaped shape made of a material such as titanium, tungsten, or molybdenum in accordance with the metal thin film 20 formed on the substrate 12, and its peripheral portion is formed by screws 1.
The support plate 1 is attached by the presser plate 17 attached in step 6.
It is fixed at 5.

The outside of the presser plate 17, screws 16, support plate 15, etc. on the periphery of the sputter target 13 is covered with a shield plate 18 made of a material such as stainless steel to prevent spatter.

Further, the sputter target 31 is formed so that the surface portion thereof facing the substrate 12 side is higher than the surface of the shield plate 18 installed at the peripheral portion. The other parts have the same configuration as the conventional device. In a preferred embodiment of the present invention, the surface of the shield plate 18 is higher than the surface of the sputter target 31 by several millimeters.

In this way, the target 31 and the shield plate 18
sputtering. According to this method, spatter substances are less likely to adhere to the surface of the shield plate 18, and abnormal discharges are eliminated, so that a uniform sputter film can be formed on the substrate without protrusions caused by minute foreign matter. Furthermore, since a target is used which has a homogeneous target material in the area immediately below the gap between the end of the target surface and the shield plate, the supporting plate 15 is This has the advantage that contaminant impurity particles are prevented from being released and contamination of the sputtered film does not occur.

In the above embodiments, the spatter target 31 only needs to have its surface portion close to or higher than the surface of the shield plate 18 so that at least the spatter substance is difficult to adhere to it, and the shape of the spatter target 31 may also be changed. It is not limited to disc-shaped ones.

〔Effect of the invention〕

As described above, according to the present invention, it becomes difficult for spatter substances to adhere to the surface of the shield plate, there is no abnormal discharge, pattern defects caused by the surface morphology of the spatter film are eliminated, and contamination of the spatter film is also reduced. This does not occur and has the effect of improving yield.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a sputter target portion of a sputtering device according to the present invention, FIG. 2 is a sectional view showing the configuration of a conventional device, and FIG. 3 is an enlarged sectional view of the sputter target portion of FIG. 2. 4 is a plan view of the sputter target shown in FIG. 2, and FIG. 5 is a sectional view of a conventional example showing a pattern defect caused by a substrate having foreign matter formed on the sputter film. In FIG. 1, 14 is a target support base;
5 is a support plate, 17 is a presser plate, 18 is a shield plate, and 31 is a sputter target.

Claims (1)

[Claims] 1. A substrate is held on one electrode side, and a sputter target 31 with a protruding central portion facing the substrate is provided on the other electrode side, and the protruding portion of the target 31 is A sputtered film is formed on the substrate using a target 31 having a shape in which a shield plate 18 covering the peripheral portion is provided and a portion directly below the gap between the end of the target surface and the shield plate also has a homogeneous target material. A sputtering method characterized by: