Spectrally tailored wafer chuck shaped light meter
US4462688A · kind A · utility
Inventor
Key dates
| Filing date | Nov 16, 1981 |
| Grant date | Jul 31, 1984 |
| Priority date | — |
| Expiry date | Nov 16, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An Ebert monochromator is modified in a wafer chuck format and adapted to received and sum spectrally tailored light in discrete band widths so that the meter emulates the photographic response of photo resist to light from a high pressure mercury lamp. The monochromator light path is placed between two closely spaced parallel mirrors (spaced apart on the order of 1/8 of an inch). The apparatus includes a circular entrance aperture having a right angle deflecting cone directed to a slit. That slit thereafter emits light to a cylindrical mirror. At the cylindrical mirror, collimated light rebounds to and on a diffraction grating. The light is chromatically classified at the diffraction grating, rebounds to the cylindrical mirror and on reflection passes to a focussing plane. At the focussing plane the particular spectra detected is displayed. Two apparatus are disclosed for tuning the spectral response of the light meter to the spectral response of the photo resist. In one embodiment moveable shutter elements at preselected intervals on either side of the focussing plane in an alternating pattern are located. By placing a photo sensor downstream of the apertures and focal plane, the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.