Tung & Associates
Method and apparatus for CMP end point detection using confocal optics
 End point detection during a CMP process on a semiconductor wafer employs confocal optics to increase signal-to-noise ratio near the end point. The use of confocal optics for sensing reflected light from the wafer surface exhibits greater selectivity where intermediate layers of metal are present in the wafer. A laser diode is used as a light source to examine the wafer surface. Light reflected back to the laser diode reduces its power state, and this power state is sensed by a current detector which outputs a signal representative of reflected light intensity. 
Taiwan Semiconductor Manufacturing Company, Ltd
B B
B24B B24B
inventional inventional
Chun-Hung Mei-Yen
Lu Li