US 6,646,223 B2 · Method for improving ash rate uniformity in photoresist ashing process equipment

Abstract

A method for improving the edge-to-center photoresist ash rate uniformity in lower temperature (typically, but not limited to <100° C.) processing of integrated circuits and micro-electro-mechanical devices. A varying gap distance 32 from the edge-to-center of the upper and lower grid plates, 30 and 31, of a plasma ashing machine is provided to allow additional flow of plasma gases into the normally semi-stagnated area near the center of the wafer being processed. This improvement overcomes the problem of slower photoresist removal in the center of the wafer. Three configurations of the invention is described, including both stepwise and continuous variation of the grid plate gap spacing and optionally, the variation of the size of grid plate holes in a parallel grid plate assembly.

Claims19

Dependent claims

A plasma asher comprising:

a plasma chamber;
a plasma source located inside said plasma chamber;
a radio frequency power supply connected to said plasma source;
a target wafer inside said plasma chamber;
and
a grid plate assembly inside said plasma chamber between said plasma source and said target wafer, said grid plate assembly comprised of at least two grid plates separated by a gap, said gap between said at least two grid plates larger in a center portion of said grid plate assembly than in an edge portion of said grid plate assembly.

3 more elements

Dependencies are inferred from the claim text.

Method for improving ash rate uniformity in photoresist ashing process equipment

Life of this patent

Method for improving ash rate uniformity in photoresist ashing process equipment

Life of this patent

Abstract

Claims19