Polishing pad and method for making the same

1. Field of the Invention

The present invention relates to a polishing pad and method for making the same, in particular, to a polishing pad with a grinding layer directly formed on the surface of a base material and a method for making the same.

2. Description of the Related Art

Generally speaking, a polishing process is performed on a rough surface through chemical mechanical polishing (CMP). In the polishing process, a slurry containing polishing particles is uniformly distributed on the surface of a polishing pad. After a polishing workpiece is pressed on the polishing pad, a repetitious and regular rubbing and polishing action is performed thereon. The polishing workpiece may be a semiconductor, a storage medium base material, an integrated circuit, an LCD flat panel glass, optical glass, or a photoelectric panel.

In the prior art, a polishing pad is made by means of multi-layer adhesion. For example, a grinding layer is adhered to a base material through a self-adhesive (referring to a multi-layer polishing pad disclosed in R.O.C. Patent Publication No. M269996), or a grinding layer made by adhesion of a plurality of thin layers is adhered to a base material through a self-adhesive (referring to a multi-layer polishing pad used for CMP disclosed in R.O.C. Patent Publication No. 200513348).

After the above conventional polishing pads are immersed in a slurry, as the grinding layer, the base material, and the self-adhesive used for adhering are made of different materials and have different compression ratios, stress is easily generated. Further, after immersion in the slurry for a long time, the adhesiveness of the self-adhesive is gradually reduced, thus resulting in unevenness of the surface of the polishing pad. In addition, during the polishing process, when the polishing machine applies a pressure to polish a polishing workpiece, protrusions on the surface of the polishing pad may cause serious abrasion of the grinding layer as well as scratches on the surface of the polishing workpiece.

Moreover, the conventional polishing pads are limited by the thickness of the grinding layer. If no long holes are formed for storing the slurry and chippings generated after polishing, the holes may be filled with the chippings generated after polishing and easily become smaller. As a result, the polishing effect is reduced, and the service life of the polishing pad is shortened.

Consequently, there is an existing need for a polishing pad and a method for making the same to solve the above-mentioned problems.

Accordingly, the present invention is directed to a polishing pad having a base material and a grinding layer. The base material is formed by covering a fiber layer with a polymer and has a surface. The grinding layer is bonded to the surface and has a plurality of holes.

The present invention is further directed to a method for making a polishing pad. The method includes: (a) providing a base material formed by covering a fiber layer with a polymer and having a surface; (b) forming a liquid-state polymer material on the surface; and (c) solidifying the liquid-state polymer material to form a grinding layer. The grinding layer is bonded to the surface and has a plurality of holes.

In the present invention, the liquid-state polymer material is directly formed on the surface of the base material, and is then solidified to form the flat grinding layer, which makes the polishing pad very even and flat. The grinding layer has attenuated structures and holes, which increases the ability to store the polishing particles distributed in a polishing liquid. In addition, the polishing pad has high compression ratio, so the polishing pad can compactly contact a polishing workpiece, and will not scratch the surface of the polishing workpiece. Therefore, the polishing effect and quality will be improved.