Camera Scanner for Submicron Particulate Photoresist Observation Technique
Original Publication Date: 1978-Apr-01
Included in the Prior Art Database: 2005-Feb-20
The submicron particulate photoresist observation technique (SP(2)OT) tool shown can be used to record particulates found upon the face of planar wafers. The high beam incident upon the wafers does not reflect into the camera, but the particulate upon the wafer causes a local diffusion that reflects in many directions and records as a white spot on the POLAROID* film. The particulates are very small in most cases and act as pin-point sources of light. Long camera exposures on the order of 15 to 60 seconds are required to gather sufficient light for good point definition.