Working process end point real time determination method
US6490497B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 2000 |
| Grant date | Dec 3, 2002 |
| Priority date | — |
| Expiry date | Jan 21, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/32078
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A working process end point real time determination method by which a working process end point can be determined accurately without an error even if a working process measurement signal has such a great variation that; the variation cannot be removed fully from and still remains in resulting smoothed data is disclosed. In the method, a working process end point is estimated by extrapolation from the variation of the average gradient of the averaged data in a predetermined period of the working process measurement signal to perform determination of the end point. Where the working process does not allow such extrapolation, it is first determined that the working process is near the working process end point based on the absolute value of the average gradient of the averaged data, and then the working process end point is determined using a short time gradient calculated from a value at the present measurement point of time and another value in the nearest past of the averaged data of the working process measurement signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.