Polishing pad and multi-layer polishing pad

Abstract

The present invention intends to provide a polishing pad and a multi-layer polishing pad that can particularly effectively suppress scratch from occurring. The polishing pad of the invention comprises at least one part selected from a groove (a) having at least one kind of shape selected from annular, lattice-like and spiral form on a polishing surface side, a concave portion (b) and a through hole (c). In the above, surface roughness of an inner surface of the part is 20 mum or less and the polishing pad is used for chemical mechanical polishing.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a polishing pad and a multi-layer polishing pad. In more detail, the invention relates to a polishing pad and a multi-layer polishing pad that have a groove having a specific shape on a polishing surface side, or a concave part having a specific shape that opens toward a polishing surface side. The polishing pad and the multi-layer polishing pad of the invention can be widely used in manufacture of semiconductor devices, and particularly preferably used in chemical mechanical polishing and the like of a surface of a material to be polished such as a wafer.[0003] 2. Description of the Prior Art[0004] Recently, chemical mechanical polishing (CMP) attracts attention as a polishing method that allows forming a surface having excellent planarity. In the CMP, with a polishing pad and a surface to be polished of a material to be polished sliding, a slurry that is an aqueous dispersion therein abrasive is dispersed is f...

AI Technical Summary

Benefits of technology

[0036] According to the polishing pad of the invention, by providing a groove (a) having a specific shape, a concave portion (b) and a through hole (c), scratches owing to foreign matters generated therein can be effectively suppressed from occurring, and polished surface is excellent in planarity.

[0037] In addition, when the groove (a) has a specific depth and width, the concave portion (b) a specific depth and minimum length of an opening, and the through hole (c) a specific minimum length of an opening, and furthermore when an area of one opening of the concave portion (b) and that of the through hole (c) are 0.0075 mm.sup.2 or more, respectively, the scratch occurring can be more assuredly suppressed.

[0038] Furthermore, when minimum lengths between adjacent openings of the groove (a), the concave portion (b) and the through hole (c) are 0.05 mm or more, efficient polishing can be forwarded while the strength of a convex portion that corresponds to the polishing surface is maintaining.

[0039] When at least part of the polishing pad includes a water-insoluble matrix including a crosslinked polymer and a water-soluble particle, surface roughness of an inner surface of the groove (a), the concave portion (b) and the through hole (c) can be easily suppressed to 20 .mu.m or less. Accordingly, the pores are not clogged by dressing, the slurry is sufficiently held and the removal rate can be made larger.

[0040] Furthermore, in case the groove (a), the concave portion (b) and the through hole (c) are formed with a method selected from cutting and molding, the surface roughness of the inner surface of each part can be easily made smaller, resulting in sufficiently suppressing the scratch from occurring.

[0041] According to the multi-layer polishing pad of the invention, the polishing can be efficiently forwarded without deforming a polishing layer during polishing. Furthermore, the scratch occurring due to the foreign matters generated in the groove and the like can be suppressed, and a polishing surface of the pad and a surface to be polished of a wafer or the like can be sufficiently brought into contact, accordingly, the removal rate can be improved.

Problems solved by technology

Even when the technique is used, however, in some cases, scratch cannot be sufficiently inhibited from being formed on a polished surface of a material to be polished.

Even when these techniques are used, however, in some cases, pores cannot be suppressed from being clogged by abrasive and polishing wastages during polishing, or pores cannot be suppressed from being clogged after dressing, and thereby, the removal rate cannot be sufficiently improved.

Still furthermore, in some cases, the slurry cannot be sufficiently uniformly distributed on the polishing pad; accordingly, the removal rate cannot be sufficiently improved and a sufficiently uniform polished surface cannot be obtained.

When there is large unevenness, a particularly large convex portion (made of, for instance, cutting residue generated when the groove is formed) drops off during polishing, resulting in causing scratches.

Furthermore, foreign matters formed from the dropped off convex portion by compressing or the like owing to a pressure and friction heat during polishing, foreign matters formed from the dropped off convex portion and polishing wastage, solid component in the slurry and the like by interacting to form foreign matters may occur the scratches in some cases.

In addition, even during dressing, in some cases, the convex portion may drops off, resulting in the similar inconvenience.

When the depth of the groove is less than 0.1 mm, it is not preferable because the lifetime of the polishing pad becomes excessively short.

It also tends to be difficult to form the concave portion or the like whose smallest length is less than 0.05 mm.

Of these, in the former, the water-soluble particles are brought into contact with a water-based medium component of the slurry (containing a medium component and a solid component) during polishing, dissolve or swell, resulting in dropping-off.

When the content of the crosslinked polymer in the water-insoluble matrix is less than 30% by volume, in some cases, an effect of containing the crosslinked polymer cannot be sufficiently exhibited.

When the elongation remaining after breaking exceeds 100%, fine fragments scraped or stretched out from a surface of the polishing pad during polishing or dressing unfavorably tend to clog the pores.

Furthermore, the dissolution or the swelling may be caused not only by contact with water but also with an aqueous mixture medium containing an alcoholic solvent such as methanol.

When the average particle diameter of the water-soluble particle is less than 0.1 .mu.m, the magnitude of the formed pores becomes smaller than the abrasive to be used; accordingly, the polishing pad that can sufficiently retain the slurry becomes difficult to obtain.

On the other hand, when the average particle diameter exceeds 500 .mu.m, the magnitude of the pores to be formed becomes excessively large; as a result, the mechanical strength and the removal rate of the obtained polishing pad tend to deteriorate.

When the content of the water-soluble particle is less than 0.1% by volume, the pores formed using the obtained polishing pad cannot be not be sufficient, and the removal rate tends to decrease.

On the other hand, when the water-soluble particles are contained exceeding 90% by volume, it tends to be difficult to sufficiently inhibit the water-soluble particle present within the polishing pad from swelling or dissolving; accordingly, it becomes difficult to maintain the hardness and the mechanical strength of the polishing pad at proper values.

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