| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy of a polishing process and hereby ensure further advantageous information by making a laser beam incident on a wafer during part of a period of time and detecting light reflected on the wafer when the wafer is on a window disposed in close vicinity of as platen hole. SOLUTION: A platen pad 18 is constructed by laminating a backing layer 20 and a polyurethane cover layer 22 on a platen 16, and a hole 30 is formed in the platen 16 and the backing layer 20 as a window. On the window a wafer 14 held by a polishing head 12 is disposed, and a laser beam 34 is made incident on the carfare of the wafer 14 transmitting the cover layer 22 through a laser interferometer 32 during part of a period of time. The laser beam 34 incident on the wafer 14 is reflected on the wafer 14, and the reflected laser beam 34 is detected by the laser interferometer 32. Hereby, accuracy of a polishing process is improved and hance useful information is ensured. |
