Polycrystalline silicon rod and method for manufacturing polycrystalline silicon rod
US9006002B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 4, 2011 |
| Grant date | Apr 14, 2015 |
| Priority date | — |
| Expiry date | Apr 19, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The length of the polycrystalline silicon rod (100) is measured with a tape measure, then the polycrystalline silicon rod (100) is hit with a hammer (120), and this hammering sound is recorded in a recorder (140) through a microphone (130). Then, an acoustic signal of the hammering sound is subjected to a fast Fourier transform and a frequency distribution is displayed. Furthermore, a peak frequency f is detected which shows the largest sound volume in the frequency distribution obtained after the fast Fourier transform. The relationship between the length (L) of the polycrystalline silicon rod and the peak frequency f is obtained, and the firmness of the polycrystalline silicon rod is determined on the basis of whether or not the peak frequency f is in a range of f≧1,471/L (region A).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.