KR20050095691A - Chemical mechanical polishing apparatus - Google Patents

Abstract

The present invention discloses a polishing pad of a chemical mechanical polishing device. The polishing pad of the chemical mechanical polishing apparatus of the present invention includes a platen, a polishing pad placed on the platen, a polishing head for pressing and supporting a wafer on a platen including the polishing pad, In the chemical mechanical polishing apparatus comprising a slurry spray nozzle for supplying a slurry to the center, the polishing pad has a plurality of groove patterns in a concentric shape on the surface, the groove pattern has the same width and space, but the depth It is characterized in that the deeper from the edge toward the center.

Description

Chemical Mechanical Polishing Device {CHEMICAL MECHANICAL POLISHING APPARATUS}

The present invention relates to a chemical mechanical polishing device, and more particularly to a polishing pad for improving the utilization efficiency of the slurry.

As semiconductor devices are miniaturized, densified, and multi-layered, finer pattern formation techniques are used, and the surface structure of the semiconductor devices is complicated and the level of interlayer insulating films is also increased.

Therefore, a chemical mechanical polishing (CMP) process is used as a planarization technique for removing a step in a specific film formed on a semiconductor substrate.

The CMP process is a process of planarizing the surface of the polishing target layer through chemical reaction with a slurry and mechanical processing with a polishing pad. Such a CMP process can obtain global planarization as compared to a reflow or etch-back process that has been conventionally used for surface planarization, and has the advantage that it can be performed at low temperature.

1 is a perspective view of an apparatus (hereinafter, referred to as a CMP apparatus) used in a conventional CMP process.

As shown, the conventional CMP apparatus includes a platen 21, a polishing pad 22 placed on the platen 21, and a polishing head 23 for pressing and supporting the wafer 10. And a slurry spray nozzle 24 for supplying the slurry 31 to the polishing pad 22.

The platen 21 is rotatable, and the polishing pad 22 placed on the platen 21 mechanically polishes the surface of the wafer 10 by interviewing the wafer 10 during polishing. The polishing head 23 is rotatable and, when performing polishing, presses and supports the wafer 10 on the platen 21 including the polishing pad 22. The slurry spray nozzle 24 supplies a slurry for polishing the surface of the wafer through a chemical reaction in the center of the polishing pad 22 during wafer polishing.

However, in the conventional CMP apparatus, since most of the supplied slurry is not used for wafer polishing and discarded, there is an undesirable problem in terms of slurry utilization efficiency.

2A and 2B are a plan view and a cross-sectional view showing a polishing pad of a conventional CMP apparatus, as shown, the conventional polishing pad 22 has the same depth (D) and width (W) in a concentric manner on its surface. ) And space (S) concentric groove patterns (G: hereinafter, groove pattern) is provided, when the slurry is supplied to the center of the rotating polishing pad 22, most of the slurry by centrifugal force Since it flows out of the polishing pad 22, the amount of slurry used for actual wafer polishing is very small.

As a result, the slurry has a large amount of the slurry is flowed down than the amount directly consumed for polishing, the utilization efficiency of the slurry is reduced.

Moreover, when the utilization efficiency of a slurry is low, since a slurry is not fully supplied to wafer polishing, a polishing rate and uniformity fall.

3 is a view for explaining the utilization efficiency of the slurry when using the conventional polishing pad, as shown, when using the conventional polishing pad 22, only about 5% of the slurry 31 actually supplied to the polishing pad 22 This wafer 10 is consumed for polishing, and it is understood that the remaining 95% flows out.

As such, the use of a large amount of slurry is not preferable because it has problems such as cost increase.

Accordingly, an object of the present invention is to provide a CMP apparatus capable of maximizing the utilization efficiency of the slurry as devised to solve the above problems.

In addition, the present invention has another object to provide a CMP apparatus that can maximize the utilization efficiency of the slurry to improve the polishing rate and uniformity and reduce the cost.

In order to achieve the above object, the present invention provides a platen, a polishing pad placed on the platen, a polishing head for pressing and supporting a wafer on a platen including the polishing pad, and the polishing pad. In the CMP apparatus comprising a slurry spray nozzle for supplying a slurry to the center portion, the polishing pad has a plurality of groove patterns in a concentric shape on the surface, having the same width and space between the groove patterns, the depth of the edge portion Provides a CMP device characterized in that the deeper toward the center.

Here, the depth of the groove pattern is about 0.4 to 0.7 inches in the center portion, 0.1 to 0.4 inches in the edge portion.

In addition, the polishing pad is further provided with a xy groove pattern at the center thereof, the xy groove pattern is formed in a circle within a radius of 2 to 4 inches when the radius of the polishing pad is 10 inches, the xy groove pattern is a concentric groove pattern It is formed to have the same width and space as.

(Example)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, describing the technical principle of the present invention, in general, the slurry is supplied to the center of the rotating polishing pad, and the supplied slurry is passed out through the edge of the polishing pad by centrifugal force. At this time, if the slurry holding capacity at the center of the polishing pad is large, the amount of slurry exiting from the polishing pad by the centrifugal force can be reduced, wherein the slurry holding capacity can be achieved by deepening the depth of the groove pattern.

Therefore, the present invention in designing the groove pattern on the surface of the polishing pad, while maintaining the same width and space of the groove, but different groove depth by area to increase the slurry holding capacity in the center of the polishing pad, thereby, Improve the efficiency of use. That is, the depth of the groove pattern is designed to be deeper toward the center of the polishing pad, thereby increasing the retention capacity of the slurry.

4A and 4B are plan and cross-sectional views of the polishing pad according to the embodiment of the present invention. Here, the same parts as in Figs. 2A and 2B are designated by the same reference numerals.

4A and 4B, the polishing pad 22 according to the present invention has several groove patterns G1 concentrically on its surface. In this case, each of the groove patterns G1 has the same width W and the space S, but the depth D becomes deeper from the edge portion toward the center portion. For example, the depth D of the groove pattern G1 is about 0.4 to 0.7 inches at the center and about 0.1 to 0.4 inches at the edge.

In addition, when the groove pattern G1 is provided, the groove pattern G1 as well as the x-y groove pattern G2 are further provided at the center of the polishing pad 22. At this time, the x-y groove pattern (G2) is preferably formed in a circle having a radius of 2 to 4 inches when the radius of the polishing pad 22 is 10 inches. The x-y groove pattern G2 serves to easily supply the slurry supplied to the center of the polishing pad 22 to the wafer 10.

In this case, since the center of the polishing pad 22 has a deeper groove depth than the edge portion, it is possible to retain a large amount of slurry at the time of supplying the slurry, thus increasing the slurry holding capacity of the polishing pad center. The slurry is prevented from rapidly flowing out to the outside by the centrifugal force.

5 is a view for explaining the slurry utilization efficiency when using the polishing pad according to an embodiment of the present invention, as shown, it is possible to use the supplied slurry 31 to polish the actual wafer 10, up to 50%, Therefore, the utilization efficiency of the slurry 31 can be considerably raised from 5% to 50%.

As a result, the present invention can increase the slurry utilization efficiency very easily by varying the depth of the groove pattern on the surface of the polishing pad for each region, thereby improving the polishing rate and uniformity during wafer polishing.

Meanwhile, in the above-described embodiment of the present invention, the slurry holding ability is increased in such a manner that the depth of the groove pattern is deeper than the edge portion, but as another embodiment of the present invention, the width and space of the groove pattern are different for each region. The same effect can be obtained.

For example, if the width of the groove pattern is designed to be wider than the center portion, or if the space between the groove patterns is designed to be narrower than the edge portion, the slurry holding ability at the center of the polishing pad can be increased. Polishing rate and uniformity can be improved.

As described above, the present invention can improve the slurry holding ability at the center of the polishing pad by changing the groove pattern shape of the polishing pad, as well as maximize the fluidity and utilization efficiency of the slurry.

Therefore, the present invention can increase the utilization efficiency of the slurry, thereby obtaining cost reduction, and in particular, improving the polishing rate and uniformity.

In addition, this invention can be implemented in various changes in the range which does not deviate from the summary.

1 is a perspective view of a conventional chemical mechanical polishing device.

2a and 2b is a plan view and a cross-sectional view of a conventional polishing pad.

3 is a view for explaining the slurry utilization efficiency in the conventional polishing pad.

4A and 4B are plan and cross-sectional views of the polishing pad according to the embodiment of the present invention.

5 is a view for explaining the slurry utilization efficiency in the polishing pad according to the present invention.

* Description of the symbols for the main parts of the drawings *

10 wafer 21 platen

22: polishing pad 23: polishing head

24: slurry spray nozzle 31: slurry

G, G1: concentric groove pattern

G2: x-y groove pattern

W: Width S: Space

D: Depth

Claims (5)

A platen, a polishing pad placed on the platen, a polishing head for pressing and supporting a wafer on the platen including the polishing pad, and a slurry spray nozzle for supplying a slurry to the center of the polishing pad. In a mechanical polishing device, The polishing pad has a plurality of groove patterns in a concentric shape on the surface, and having the same width and space between the groove patterns, the depth is deeper from the edge portion to the center portion. 2. The chemical mechanical polishing apparatus according to claim 1, wherein the groove pattern has a depth of 0.4-0.7 inches in the center portion and 0.1-0.4 inches in the edge portion. The chemical mechanical polishing apparatus of claim 1, wherein the polishing pad further includes an x-y groove pattern at a central portion thereof. 4. The chemical mechanical polishing apparatus according to claim 3, wherein the x-y groove pattern is formed in a circle within a radius of 2 to 4 inches when the polishing pad has a radius of 10 inches. The chemical mechanical polishing apparatus according to claim 3, wherein the x-y groove pattern is formed to have the same width and space as the concentric groove pattern.