In-process film thickness monitoring system
US5684574A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1995 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Oct 31, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C14/544
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A beam emitted from a light source including the characteristic wavelength of flown particles in a film forming system is interrupted by a beam chopper in a predetermined cycle, and is then divided into a probing beam and a reference beam by a beam divider. The probing beam passes through a particle flight area and is then injected into a photo detector through an optical filter, and a probing signal is outputted. A reference signal is obtained from the reference beam in the same manner. A data processor detects the phase and level of both signals, so that an absorbance, i.e., a film forming rate for the flown particles is estimated. The film forming rate is integrated with time so that a film thickness is estimated. Thus, the range of the applicable film forming rate is wide. In addition, it is possible to perform continuous monitoring with high precision also in an atmosphere where a large amount of light having the same wavelength as the characteristic wavelength of the flown particles is generated, as in sputtering systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.