Exposure of photo resist
AssigneeGTE Automatic Electric Inc.
InventorsRichard Jarocinski, William R. Keaton, Joseph L. Magennis
Life of this patent
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Abstract
A method and apparatus for limiting the interference caused by shadows of minute particles of opaque matter that settles on the surface of an assembly of a metal substrate, a resist and an overlay by placing a second glass overlay on top of the assembly to raise the surface to a level where the shadows of any particles resting there will be diffused.
Claims2
A method of reducing the production of defective circuit boards due to the presence of minute opaque particles that may settle onto the cover surface of an assembly of a mask, a resist and a metal substrate prior to exposing said resist to radiation including the step of placing a second cover sheet over said assembly of a thickness sufficient to permit the diffusion of any shadows produced by minute particles resting on the cover surface.
Dependencies are inferred from the claim text.