KR980012036A - Chemical mechanical polishing apparatus - Google Patents

Abstract

The present invention relates to a CMP apparatus. In the CMP apparatus according to the present invention, a ring-shaped plate having diamond particles of an appropriate size is attached as means for restoring the surface state of a pad layer provided with CMP of a wafer.

The use of such a ring-shaped plate can improve the reproducibility in the subsequent wafer CMP process since the pad layer can be restored to its original state of recovery, that is, the initial flat surface and the appropriate surface roughness, .

Description

Chemical mechanical polishing apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical mechanical polishing (hereinafter referred to as MP) apparatus, and more particularly, to a ring-shaped plate having diamond particles attached thereto for restoring surface roughness of a pad layer.

In the CMP process, the surface roughness of the polishing pad layer (hereinafter, referred to as pad layer) is such that the surface of the pad layer becomes smooth when the wafer is polished, resulting in poor uniformity of polishing in subsequent wafer polishing and poor reproducibility It is necessary to restore the surface roughness. With this necessity, in the prior art, the surface roughness of the pad layer is restored by applying a certain pressure to a flat plate (hereinafter referred to as "diamond plate"

The distribution of the frictional force between the diamond plate and the pad layer using the diamond plate provided in the conventional CMP apparatus is shown in Fig.

FIG. 1 is a graph showing the distribution of frictional force between the diamond layer-attached flat plate and the pad layer at the instant when the surface roughness of the pad layer is restored using a CMP apparatus having a flat plate with diamond particles according to the prior art Fig.

1, the frictional forces generated between the pad layer 10 and the diamond plate 12 when using the prior art diamond planes are shown by arrows 11 and 11a, Layer 10 and the relatively short arrow represents the frictional force of the diamond plate 12. The frictional force depends on the relative rotation between the pad layer 10 and the diamond plate 12. That is, the rotation of the pad layer 10 and the left side of the diamond plate 12 is the same as the rotation direction (upper side) of the pad layer 10. The frictional force between the flat plate 12 and the pad layer 10 on the left side of the diamond plate 12 is reduced. However, the frictional force between the flat plate 12 and the pad layer 10 increases gradually from the left side to the right side of the flat plate 12. This difference in frictional force can be easily found by referring to the graph 14 showing the distribution of the frictional force according to the position of the diamond plate 12. [

Accordingly, when the surface roughness of the pad layer is restored by using the CMP apparatus according to the related art, a certain amount of pad surface is clogged each time the surface roughness is repeated. Therefore, as the number of times is increased, the pad layer is curved on a flat surface It will be cotton. Accordingly, since the life time of the pad layer is shortened and the initial and later uniformity characteristics are different, a problem of reproducibility of the subsequent wafer occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a CMP apparatus which forms a uniform portion having no slope of frictional force in a certain region of a pad layer in order to solve the problems of the prior art.

FIG. 1 is a plan view showing a plan view of a device in a step of restoring the surface roughness of a pad layer using a CMP apparatus having a diamond particle-attached plate according to a conventional technique, and a frictional force distribution between a diamond- to be.

FIGS. 2 and 3 are a plan view and a cross-sectional view (FIG. 2A-2) of a ring-shaped plate with diamond particles used for restoring the surface roughness of a pad layer provided in a chemical mechanical polishing apparatus according to the present invention, A 'direction).

FIG. 4 is a cross-sectional view showing the moment when the surface roughness of the pad layer is restored by using a CMP apparatus equipped with a ring-shaped plate with diamond particles of FIG. 1 attached thereto.

5 is a plan view of the apparatus in a step of recovering the surface roughness of the pad layer using a CMP apparatus equipped with a diamond particle-attached plate according to the present invention and a top view showing a friction force distribution between a plate and a pad layer with diamond particles attached thereto to be.

DESCRIPTION OF THE REFERENCE NUMERALS

40: ring-shaped plate 42: attachment plate

In order to achieve the above object, a CMP apparatus according to the present invention includes a means for directly rubbing against a surface of a pad layer for recovering a surface state of a pad layer subjected to a CMP process with a wafer, Wherein the front surface of the bottom is a ring-shaped plate uniformly convex.

Diamond particles of a certain size are attached to the bottom of the means.

Accordingly, the present invention can improve the reproducibility in the subsequent wafer CMP process since the pad layer can be restored to its original state, that is, the initial flat surface and the appropriate surface roughness, together with the lifetime vapor of the pad layer as compared with the prior art.

Hereinafter, a CMP apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

2 and 3 are a plan view and a cross-sectional view (A-A in Fig. 2) of a ring-shaped plate with diamond particles used for restoring the surface roughness of a pad layer provided in a chemical mechanical polishing apparatus according to the present invention FIG. 4 is a cross-sectional view showing a moment when the surface roughness of the pad layer is restored by using the CMP apparatus equipped with the ring-shaped plate with the diamond particles of FIG. 1 mounted thereon, FIG. 5 is a cross- FIG. 2 is a plan view showing a plan view of the device in the step of recovering the surface roughness of a pad layer using a CMP apparatus having a plate and a frictional force distribution between a plate and a pad layer having diamond particles attached thereto. FIG.

Referring to FIG. 2, reference numeral 40 denotes a ring-shaped plate to which diamond of a predetermined size is attached as means for restoring the surface roughness of the pad layer in the CMP apparatus according to the present invention. And reference numeral 42 denotes a plate (hereinafter, referred to as an attachment plate) for attaching the ring-shaped plate 40 to the body of the CMP apparatus. To further examine the shapes of the ring-shaped plate 40 and the attachment plate 42, refer to FIG. 3, which is a cross-sectional view taken along the line A-A 'in FIG. Referring to FIG. 3, it can be seen that the ring-shaped plate 40 is attached to the rim of the mounting plate 42. The attachment of the attachment plate 42 to the CMP device body can be easily understood with reference to FIG. 4 shows the moment when the surface of a part of the pad layer 46 attached on the polishing table 44 is restored by using the ring-shaped plate 40 according to the present invention. In the CMP body 48, And the ring-shaped plate 40 attached to the pad layer 46 is rotated in the same direction as the rotation direction of the pad layer 46. The attachment plate 42 to which the ring-shaped plate 40 is attached is attached to the CMP body 48 via a magnetic pad 50. This rotation causes a frictional force between the ring-shaped plate 40 and the pad layer 46, which depends on the position between the ring-shaped plate 40 and the pad layer 46. The frictional force is shown by the arrows 47 and 47a in the figure, the reference numeral 47 represents the frictional force of the pad layer 46, and the reference numeral 47a represents the frictional force of the ring-shaped plate 40. When the directions of frictional force are the same, they are shown in the same direction, and when they are different, they are shown in the opposite direction. The magnitude of the frictional force is indicated by the length of the arrow. Therefore, referring to FIG. 5, the frictional force distribution along the horizontal line B-B 'shown in FIG. 5 will be examined. On the left side of the ring-shaped plate 40, the rotational direction is the same as the direction of the pad layer 46, so that the frictional force is small. On the other hand, on the right side of the ring-shaped plate 40, the frictional force increases because it is opposite to the rotational direction. In the central portion of the ring-shaped plate 40, there is no part frictioned with the pad layer 46, so there is no frictional force. When this analysis is applied to the front surface of the ring-shaped plate 40, as in the graph 52 of the friction force between the ring-shaped plate 40 and the pad layer 46 shown in the lower portion of FIG. 5, There is a region in which a uniform friction exists which has a friction force but does not have a tilt. In this portion, since the pad layer is uniformly polished over the entire surface, the surface roughness can be easily recovered and recovered to the initial state. That is, the reproducibility of the pad layer is improved at this portion. When the subsequent wafer is subjected to CMP in such a portion, the entire surface is polished uniformly, thereby improving the CMP and improving the reproducibility of the surface state of the pad layer for the subsequent process.

As described above, the CMP apparatus according to the present invention includes a ring-shaped plate to which particles of diamond having an appropriate size are attached as means for restoring the surface state of the pad layer subjected to CMP of the wafer.

The use of such a ring-like plate can restore the pad layer to its original state of recovery, that is, the initial flat surface and proper surface roughness, together with the vapor of the pad layer life as compared with the prior art, so that the reproducibility in the subsequent wafer CMP process Can be improved.

It is apparent that many modifications may be made by those skilled in the art without departing from the scope of the present invention.

Claims (2)

And a means for directly rubbing against the surface of the pad layer in order to recover the surface state of the pad layer subjected to the CMP process with the wafer, characterized in that the means is a ring-shaped plate with the entire surface of the bottom being uniformly convex Lt; / RTI > The CMP apparatus according to claim 1, wherein a diamond particle of a predetermined size is attached to the bottom of the means. ※ Note: It is disclosed by the contents of the first application.