发明名称 |
Frequency measuring device, polishing device using the same and eddy current sensor |
摘要 |
A frequency measuring device capable of accurately detecting an end point of polishing a semiconductor wafer by obtaining a frequency measurement result highly accurately in a short period of time. A device FC, which measures the frequency of a measured signal comprises a counting section including a plurality of n-nary counters, a time reference circuit which outputs a time reference signal for every predetermined time interval, and a plurality of gate circuits whose outputs are connected to the inputs of the n-nary counters. The gate circuits receive the measured signal at a first input and receive the time reference signal at the predetermined time intervals at a second input. With this structure, the counting section supplies the frequency measured result of the measured signal every predetermined time interval.
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申请公布号 |
US7046001(B2) |
申请公布日期 |
2006.05.16 |
申请号 |
US20010982025 |
申请日期 |
2001.10.19 |
申请人 |
EBARA CORPORATION |
发明人 |
TADA MITSUO;YAMASAKI HIRONOBU;SUTO YASUNARI |
分类号 |
G01B7/06;H01L21/304;B24B37/013;B24B37/04;B24B49/04;B24B49/10;G01D5/20;G01N27/72;G01R23/10;G01R33/12 |
主分类号 |
G01B7/06 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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