| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To accurately detect the presence and a size of a crack in a silicon wafer. <P>SOLUTION: An impact is applied onto the silicon wafer 1 to generate vibration, a vibration frequency thereof is converted into an electric signal via a microphone, and an integrated value of power spectra of the vibration frequency is calculated to be compared with an integrated value of power spectra of a vibration frequency preliminarily found. <P>COPYRIGHT: (C)2004,JPO</p> |
