Polishing pad that minimizes occurrence of defects and process for preparing the same
The present invention relates to a polishing pad that minimizes the occurrence of defects and a process for preparing the same, Since the polishing pad comprises fine hollow particles having shells, the glass transition temperature (Tg) of which is adjusted, the hardness of the shells and the shape of micropores on the surface of a polishing layer are controlled. Since the content of Si in the polishing layer is adjusted, it is possible to prevent the surface damage of a semiconductor substrate caused by hard additives. As a result, the polishing pad can provide a high polishing rate while minimizing the occurrence of defects such as scratches on the surface of a semiconductor substrate during the CMP process.
1. A polishing pad, which comprises a polishing layer,
wherein the polishing layer comprises fine hollow particles having shells,
the glass transition temperature (Tg) of the shells of the fine hollow particles is 110° C. or less, and
the polishing layer satisfies the following Relationship (1):
0
<
DSi
S
T
g
≤
15
(
1
)
in the above Relationship,
DSi is the content of Si (ppmw, parts per million by weight) with respect to the total weight of the polishing layer,
STg is the glass transition temperature (° C.) of the shells of the fine hollow particles, and
DSi/STg is a ratio between the values exclusive of units.
2. The polishing pad of claim 1 , wherein the DSi/STg in the above Relationship (1) is 1 to 5.
3. The polishing pad of claim 1 , wherein the glass transition temperature (Tg) of the shells of the fine hollow particles is 70° C. to 110° C., and the content of Si in the polishing layer is less than 1,000 ppmw.
4. The polishing pad of claim 1 , wherein the glass transition temperature (Tg) of the shells of the fine hollow particles is 70° C. to 90° C., and the content of Si in the polishing layer is less than 500 ppmw.
5. The polishing pad of claim 1 , wherein the fine hollow particles have an average particle diameter of 10 μm to 70 μm.
6. The polishing pad of claim 5 , wherein the fine hollow particles have an average particle diameter of 30 μm to 60 μm.
7. The polishing pad of claim 1 , wherein the fine hollow particles are employed in an amount of 0.1% by weight to 3% by weight with respect to the total weight of the polishing layer.
8. The polishing pad of claim 1 , wherein the shells of the fine hollow particles comprise at least one selected from the group consisting of a vinylidene chloride-based copolymer, an acrylonitrile-based copolymer, a methacrylonitrile-based copolymer, and an acrylic-based copolymer.
9. The polishing pad of claim 1 , wherein the fine hollow particles comprise a hydrocarbon having 1 to 7 carbon atoms therein.
10. The polishing pad of claim 1 , wherein the polishing pad has a polishing rate (or removal rate) of 700 Å/min or more against a tungsten layer.
11. The polishing pad of claim 1 , wherein the polishing layer has a plurality of micropores of an opened cell exposed to the outside, in which the micropores are derived from the fine hollow particles.
12. The polishing pad of claim 1 , wherein the polishing layer has a surface hardness of 50 shore D to 70 shore D.