JPH11140638A - Sputtering device and collimator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction in film thickness at the bottoms of deep holes on a semiconductor substrate without causing a varied film thickness distribution in the thickness of the film deposited on the substrate by distributing the opening diameters of the plural apertures formed on a collimator so as to extend toward the end from the central part of this collimator and maintaining the specified ratio of the opening diameters and opening depths. SOLUTION: The plural apertures are formed on the collimator 11 and the opening diameters thereof are smaller in the central part of the collimator 11 and large in the peripheral parts thereof. The ratios of the depths of the apertures to the opening diameters in the central part and peripheral part of the collimator 11 are both constant and are specified to 1 to 2. When sputtering is executed by installing such collimator 11, the deposition rate may be made uniform over the entire surface of the semiconductor substrate and the film thickness of the sputter particles deposited on the substrate are made uniform. The sputter particles hardly adhere to the flanks of the microholes formed on the semiconductor substrate and deposited uniformly on the bases, thereby making it possible to obtain the uniform film thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus having a collimator.

[0002]

2. Description of the Related Art As semiconductor integrated circuit devices become more highly integrated, patterns become finer. Therefore, for example, in a manufacturing process of a semiconductor device, there is a step of performing sputtering on a surface of a semiconductor substrate including a bottom portion of a hole having a diameter of 0.4 μm and a depth of about 1.2 μm formed on the semiconductor substrate. At the time of this sputtering, a collimator is arranged between the target and the semiconductor substrate so that the film thickness at the bottom of the hole does not become thin, and sputter particles that scatter obliquely among sputter particles scattered from the target are eliminated. In addition, a sputtering device that allows only sputtered particles scattered in the vertical direction to reach the semiconductor substrate is used.

[0003] A sputtering apparatus provided with such a collimator is disclosed, for example, in Japanese Patent Laid-Open Publication No. 1-116070. A sputtering apparatus provided with the collimator will be described with reference to FIGS. That is, in FIG. 6, the vacuum processing chamber 10 in which the vacuum is
In FIG. 1, a semiconductor substrate 107 and a target 105 are provided, and a collimator 111 having a large number of openings as shown in FIG. FIG. 8 is a cross-sectional view of the collimator 111. As shown in FIG. 8, the ratio of the opening diameter x′1 to the opening depth y′1 of the collimator 111 is usually about 1: 1. The same length. During sputtering, of the sputtered particles 109 scattered in various directions from the target 105, the sputtered particles scattered obliquely adhere to the inner wall of the opening of the collimator 111 and do not reach the semiconductor substrate 107. On the other hand, the sputtered particles scattered in the vertical direction reach the semiconductor substrate 107 through the opening of the collimator 111. By disposing the collimator 111 in this manner, the semiconductor substrate 10
Since the film 7 is formed only by sputtered particles scattered in the vertical direction, the film thickness at the bottom of the hole does not become thin.

It is desirable that the deposition rate of sputtered particles generated from the target is uniform at any position on the surface of the semiconductor substrate. However, in the above-described sputtering apparatus, there is a problem in that the deposition rate is distributed depending on the distance between the target and the substrate surface, the position where the sputtered particles are projected on the target, and the angle formed by the substrate, and thus the film thickness cannot be uniform. Was. At the time of sputtering, the amount of adhesion at the center of the semiconductor substrate is the largest, and the amount of adhesion tends to decrease toward the edge of the semiconductor substrate. For this reason, generally, only about one third of the effective area of the target can be used.

A method for improving the film thickness distribution of this sputtering apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-232965, and a sputtering apparatus with this improved film thickness distribution will be described with reference to FIGS. . That is, in FIG.
A plurality of substrates 206 are placed on a rotary table 208 provided so as to be parallel to the surface of the target 204 so as to oppose the plane of the target 204, and the substrate 206 is sputtered while rotating the rotary table 208 by a rotation shaft 213. A film is formed thereon. At this time, the shielding plate 209 is placed in the space between the target 204 and the substrate 206 with the turntable 2.
08 and concentrically. As shown in FIG. 10, a circular hole 211 having the same position as the center of the target 204 is provided in the shielding plate 209, and circular holes 211 are provided at both ends of the circular hole 211.
A pair of shutters 210 whose vertices are an arbitrary point on an arc centered on the rotary table 208 with the radius between the center of the rotary table 208 and the center of the rotary table 208 as an axis connecting the center of the rotary table 208 and the center of the circular hole 211 The slits are formed at symmetrical positions. It is stated that the shutter 210 blocks sputtered particles reaching the substrate 206, so that the distribution of deposited film thickness can be made uniform.

[0006]

However, in order to perform sputtering on the surface of the semiconductor substrate including the bottom of the hole, it is difficult to use a sputtering apparatus having the improved film thickness distribution. The reason is that even if a collimator is provided in the sputtering apparatus in which the film thickness distribution is improved, the sputtered particles relatively move with respect to the semiconductor substrate surface because the semiconductor substrate is moving during sputtering. This is because the particles do not fly vertically and the sputtered particles cannot reach the bottom of the hole, and the film thickness at the bottom of the hole becomes thin. Furthermore, the size of a semiconductor substrate used for manufacturing a semiconductor integrated circuit device has been shown in a sputtering device having an improved film thickness distribution because the diameter of the semiconductor substrate is becoming larger and larger in order to reduce manufacturing costs. The use of such a rotary table is problematic because the apparatus becomes very large.

According to the present invention, the thickness of sputtered particles deposited on a substrate does not have a problematic thickness distribution.
It is another object of the present invention to provide a sputtering apparatus capable of performing sputtering without reducing the thickness of sputtered particles at the bottom of a deep hole.

[0008]

According to a first aspect of the present invention, there is provided a sputtering apparatus having a collimator disposed between a target material and a semiconductor substrate. The diameter of the plurality of openings formed in the meter has a distribution that extends from the center to the end of the collimator, and the ratio of the opening diameter and the opening depth of the opening of the collimator is constant. It is characterized in that it is a certain sputtering apparatus. The second invention of the present application is the sputtering apparatus according to the first invention, wherein a ratio of an opening depth of the opening of the collimator to an opening diameter of 1 is 1 or more and 2 or less. . Further, the third invention of the present application is a collimator provided between a target material and a semiconductor substrate in a sputtering apparatus, wherein the diameter of the plurality of formed openings increases from the center to the end. The collimator is characterized by having a distribution that elongates the opening and has a constant ratio between the opening diameter and the opening depth of the opening. Further, the fourth invention of the present application is:
In addition to the third aspect, the collimator is characterized in that the ratio of the opening depth to the opening diameter of the opening of the collimator is 1 or more and 2 or less.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sputtering apparatus according to an embodiment of the present invention will be described with reference to FIGS. In FIG.
A semiconductor substrate 7 and a target 5 are provided in a vacuum processing chamber 1 in which a vacuum is created by a vacuum pump 3, and a collimator 11 is provided therebetween. Of the sputtered particles 9 scattered from the target 5, those that have passed through the collimator 11 are deposited on the semiconductor substrate 7. FIG. 2 is a plan view of the collimator 11.
FIG. 3 shows a cross-sectional view. As can be seen from FIG. 2, a plurality of openings are formed in the collimator 11, and the opening diameter is small at the center of the collimator 11 and large at the periphery. As shown in FIG. 3, the ratio between the opening diameter x1 and the opening depth y1 at the center of the collimator 11 and the ratio between the opening diameter x2 and the opening depth y2 at the peripheral portion are both 1: 1.

When the sputtering is performed by removing the collimator 11 of the sputtering apparatus according to one embodiment of the present invention, the distance between the target 5 and the surface of the semiconductor substrate 7 and the position of the sputtered particles 9 on the target 5 are determined. Depending on the angle formed by the semiconductor substrate 7, a distribution occurs in the film thickness. The thickness of the sputtered particles 9 deposited on the semiconductor substrate 7 is as shown in FIG.
As shown in the figure, the thickness is thicker at the center of the semiconductor substrate 7 and thinner at the periphery. However, when the collimator 11 of the sputtering apparatus according to one embodiment of the present invention is installed and sputtering is performed, the opening diameter at the center of the collimator 11 is small and the diameter at the periphery is large. Can be made uniform over the entire surface of the semiconductor substrate. Therefore, the film thickness of the sputtered particles 9 deposited on the semiconductor substrate 7 becomes uniform on the semiconductor substrate 7 as shown in FIG.

The opening diameter x1 and the opening depths y1 and x1
When the aperture ratio between 2 and y2 is smaller than 1, the target 5 has a flying angle of 45 degrees or more, which is the elevation angle of the sputtered particle 9 projection position and the angle formed by the semiconductor substrate 7 is sputtered. Therefore, the sputtered particles 9 are easily deposited on the side surfaces of the fine holes formed on the semiconductor substrate 7 and hardly enter the bottom. Therefore, a uniform film thickness cannot be obtained. On the other hand, if the opening ratio of the opening diameter to the opening depth exceeds 2, the proportion of sputter particles adhering to the collimator 11 increases, the deposition rate of the sputter particles 9 on the semiconductor substrate 7 decreases, and the throughput deteriorates. Become. In addition, there is a problem in that the consumption of the target increases, the generation of particles increases, and the time for cleaning and replacing the collimator becomes frequent. According to the second invention of the present application, the opening ratio of the opening diameter to the opening depth is in the range of 1 or more and 2 or less and the elevation angle is limited to 63.5 degrees. It becomes difficult to adhere to the side surface of the hole, and it becomes possible to deposit uniformly on the bottom surface.
Therefore, a uniform film thickness can be obtained. As described above, in the sputtering apparatus according to one embodiment of the present invention, not only can the thickness of the sputtered particles 9 to be deposited be uniform, but also the ratio between the opening diameter of the collimator 11 and the opening depth is constant. In addition, sputtering can be performed without reducing the thickness of sputter particles deposited on the bottom of the deep hole in the surface of the semiconductor substrate 7.

[0012]

EXAMPLE As an example of the present invention, a step of performing sputtering on the surface of a semiconductor substrate including a bottom portion of a hole having a diameter of 0.25 μm and a depth of 2.0 μm formed on the semiconductor substrate 7 was performed. In this embodiment, as the collimator, the opening diameter is 10.0 mm at the center and 12.5 mm at the periphery, which is small at the center and large at the periphery, and the ratio of the opening diameter to the depth of the opening is the center. A 1: 1 part and a peripheral part were prepared. When the sputtering is performed by removing the collimator 11 of the sputtering apparatus of the present invention, the film thickness of the sputtered particles 9 deposited on the semiconductor substrate 7 is thick at the center of the semiconductor substrate 7 as shown in FIG. It became thin in part. However, when the collimator 11 according to the embodiment of the present invention was attached, the film thickness of the sputtered particles 9 deposited on the semiconductor substrate 7 became uniform as shown in FIG. Furthermore, the film thickness of the sputtered particles 9 formed on the semiconductor substrate 7 and deposited on the bottom of the hole is also
The film thickness deposited on the surface of the semiconductor substrate 7 was uniform.

In the embodiment shown here, the collimator 1
1 shows a case where the opening diameter of the opening is smaller at the center and larger at the periphery, but the distribution of the opening diameter of the opening of the collimator 11 is obtained by removing the collimator 11 of the sputtering apparatus, Is performed, the opening diameter of the opening of the collimator 11 corresponding to the place where the thickness of the sputtered particles 9 deposited on the semiconductor substrate 7 is large is small, and the collimator corresponding to the place where the thickness of the deposited sputtered particles 9 is small. It is sufficient if the distribution is such that the opening diameter of the 11 opening portions is increased.

[0014]

When the sputtering apparatus of the present invention is used for manufacturing a semiconductor device, the thickness of the sputtered particles deposited on the surface of the semiconductor substrate does not become thinner without the film thickness of the sputtered particles deposited on the bottom of the deep hole in the surface of the semiconductor substrate being reduced. Since the film thickness can be made uniform, the yield can be improved as compared with the case where a conventional sputtering apparatus is used. Further, the sputtering apparatus according to the present invention requires only replacement of the collimator part from the conventional sputtering apparatus having a collimator, and therefore little cost is required for remodeling.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a collimator of the sputtering apparatus according to one embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a collimator of a sputtering apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing a film thickness distribution of sputtered particles deposited on the surface of a semiconductor substrate in one embodiment of the present invention.

FIG. 5 is a diagram showing a film thickness distribution of sputtered particles deposited on a semiconductor substrate surface when a collimator is not used according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a conventional sputtering apparatus.

FIG. 7 is a plan view of a collimator of a conventional sputtering apparatus.

FIG. 8 is an enlarged cross-sectional view of a collimator of a conventional sputtering apparatus.

FIG. 9 is a view showing a sputtering apparatus according to a conventional example.

FIG. 10 is a diagram showing a sputtering apparatus according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum processing chamber 3 Vacuum pump 5 Target 7 Semiconductor substrate 9 Sputtered particles 11 Collimator 101 Vacuum processing chamber 103 Vacuum pump 105 Target 107 Semiconductor substrate 109 Sputtered particles 111 Collimator 204 Target 206 Substrate 208 Rotary table 209 Shielding plate 210 Shutter 211 circle Hole 212 Trace of rotation axis at center of substrate 213 Rotation axis

Claims (4)

[Claims] 1. A sputtering apparatus having a collimator disposed between a target material and a semiconductor substrate, wherein a plurality of apertures formed in the collimator have an opening diameter from a center to an end of the collimator. A sputter device having a distribution extending toward a portion, wherein a ratio of an opening diameter of the opening of the collimator to an opening depth is constant. 2. The sputtering apparatus according to claim 1, wherein the ratio of the opening depth to the opening diameter of the opening of the collimator is 1 or more and 2 or less. 3. A collimator disposed between a target material and a semiconductor substrate in a sputtering apparatus, wherein a plurality of openings have a distribution in which opening diameters extend from a center to an end. Wherein the ratio of the diameter of the opening to the depth of the opening is constant. 4. The collimator according to claim 3, wherein a ratio of an opening depth to an opening diameter of the opening of the collimator is 1 or more and 2 or less.