Process of forming graded aperture masks
AssigneeBuckbee-Mears Company
InventorRoland Thoms
Life of this patent
Estimating the term…
Abstract
A process for forming openings of varying sizes in an aperture mask by determining an over-etch factor wherein the over-etch factor is determined by the time of etching through an etchant resist pattern located on opposite sides of an aperture mask material to produce an opening of predetermined size and shape followed by individually sizing the opening in the etchant resist so that etching from both sides of the aperture mask material produces etched openings of various sizes throughout the aperture with the sizing of the opening in the etchant resist characterized by having substantially constant over-etch factor even though the final openings in the aperture masks are of various sizes.
Claims8
The process of forming a plurality of openings in an aperture mask which vary in size from the center of the aperture mask to the periphery of the aperture mask comprising:
- applying a layer of etchant resist to opposite surfaces of an aperture mask material, determining an over-etch factor for the aperture mask material by determining the depth of the etch from opposite surfaces of said aperture mask material;
- laying out a pattern of openings in an etchant resist located on opposite surfaces of the aperture mask material wherein the size of the openings in etchant resist is determined by selecting a resist opening wherein the over-etch factor is substantially constant for etching openings in the aperture mask material;
- and
- etching the aperture mask material through the openings in the etchant resist.
The process of forming openings in an aperture mask wherein the apertures are of various sizes comprising the step of:
- applying a first etchant resist film on one side of a sheet of aperture mask material;
- applying a second etchant resist film on the opposite side of the sheet of aperture mask material;
- forming a first set of openings in said first etchant resist film to provide a region for etching the aperture mask material;
- determining an over-etch factor for etching an opening in said aperture mask material;
- and
- forming a second set of openings in said second etchant resist film with the size of the opening in said second resist selected so that the over-etch factor is substantially constant throughout said aperture mask.
Dependencies are inferred from the claim text.