Process to suppress lithography at a wafer edge
AssigneesInternational Business Machines Corporation, Infineon AG
InventorsWolfgang Bergner, Linda Chen, Stephan Kudelka, Franz X. Zach
Life of this patent
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Abstract
Damage to the rim of a semiconductor wafer caused by etching processes is reduced by forming a rim of photoresist or other material around the outer edge of the wafer that has a thickness such that images projected on the rim are sufficiently out of focus that they do not develop, so that etching takes place only in the interior.
Claims20
A method of manufacturing a set of integrated circuits on a wafer comprising the steps of:
- preparing an integrated circuit substrate;
- depositing a layer of photosensitive material having a blocking thickness over said wafer;
- exposing said photosensitive material to leave developed material in a blocking area at the outer edge of said wafer;
- developing said photosensitive material to leave a layer of blocking material in said area;
- depositing a layer of patterning photoresist on said wafer;
- exposing said layer of patterning photoresist inside said blocking area with a set of images of a component pattern of a component of said integrated circuit;
- etching said wafer through said component pattern;
- and
- continuing with processing said integrated circuit.
A method of etching a set of apertures in a workpiece comprising the steps of:
- depositing a layer of photosensitive material having a blocking thickness over said workpiece;
- exposing said photosensitive material in a blocking area at the outer edge of said workpiece;
- developing said photosensitive material to leave a layer of blocking material in said area;
- depositing a layer of patterning photoresist on said workpiece;
- exposing said layer of patterning photoresist inside said blocking area with a set of images of said set of apertures;
- and
- etching said workpiece through said component pattern.
A semiconductor wafer comprising an inner area for the fabrication of integrated circuits and an outer rim having a thickness such that when an image projected on said wafer in said inner area is in focus, an image projected on said outer rim is out of focus.
Dependencies are inferred from the claim text.