Polishing head, CMP apparatus having polishing head, and semiconductor integrated circuit manufacturing method using CMP apparatus
View Patent ↗A polishing head of a CMP apparatus includes a polishing pad, an air bag brought into contact with a rear surface of a wafer on the polishing pad and configured to press a front surface of the wafer against the polishing pad, and a top ring surrounding the air bag and the wafer. A portion of the air bag brought into contact with a peripheral portion of the wafer is thicker in film thickness than a portion of the air bag brought into contact with a central portion of the wafer. The polishing head is capable of applying even pressure to press down the wafer evenly throughout the entire wafer plane to improve the evenness of polishing.
1. A polishing head of a CMP apparatus, comprising:
a polishing pad;
a first air bag and a second air bag, which are in contact with a rear surface of a wafer mounted on a front surface of the polishing pad, and which are configured to press a front surface of the wafer against the polishing pad; and
a top ring surrounding the first air bag, the second air bag, and the wafer,
the first air bag, which is in contact with a central portion of the wafer, and the second air bag, which is in contact with a peripheral portion of the wafer, being separate bag bodies, and
the first air bag, which is in contact with the central portion of the wafer, has a first film thickness, and the second air bag, which is in contact with the peripheral portion of the wafer, has a second film thickness that is thicker than the first film thickness.
2. A polishing head according to claim 1 , wherein the first air bag is a circular air bag in plan view, and the second air bag in plan view is a torus-shaped air bag arranged around the circular air bag.
3. A polishing head according to claim 1 , wherein the first air bag is a circular air bag in plan view, and the second air bag in plan view is an aggregation of a plurality of circular air bags arranged around the first air bag and each smaller than the first air bag in size.
4. A polishing head according to claim 1 , wherein the first air bag is an aggregation of a plurality of circular air bags in plan view, and the second air bag in plan view is an aggregation of a plurality of circular air bags arranged around the first air bag.
5. A polishing head according to claim 1 , wherein the first air bag is a circular air bag in plan view, and the second air bag in plan view is a coiled-hose shape air bag arranged around the circular air bag.
6. A polishing head according to claim 1 , wherein the first air bag is a first coiled-hose shape air bag in plan view, and the second air bag in plan view is an aggregation of a plurality of second coiled-hose shape air bags arranged around the first coiled-hose shape air bag and each smaller than the first coiled-hose shape air bag in size.
7. A polishing head according to claim 1 , wherein the first air bag is an aggregation of a plurality of coiled-hose shape air bags in plan view, and the second air bag in plan view is an aggregation of a plurality of coiled-hose shape air bags arranged around the first coiled-hose shape air bag.