US 6,662,145 B1 · Method, equipment, and recording medium for controlling exposure accuracy

Abstract

A method, equipment, and a recording medium of controlling exposure accuracy enabling position accuracy to be around ±15 nm by double exposures under different optical conditions. The first exposure is carried out under an optical condition A1 suitable for dense patterns, that is 30-40% the total quantity of light. This optical condition A1 can be optimized by change in the pattern size and the photoresist. After cleaning for restoring the elongation of the wafer and changing the illuminating optical system, the second exposure is carried out under an optical condition B1 suitable for sparse patterns, that is 70-60% the total quantity of light. By this the positioning error of the reticle scan stage, which is a cause of misalignment, is eliminated, and in addition, error caused by the expansion/contraction of the wafer due to cleaning can also be eliminated. As a result, resolution can be improved without lowering the throughput.

Claims4

Dependent claims

A method of controlling exposure accuracy comprising,

a step of placing a wafer on the wafer scan stage of an aligner;
a step of placing a reticle on the reticle scan stage of said aligner;
a step of positioning said reticle;
a first exposure step for exposing said wafer, said first exposure is 30 to 40% of the total exposure;
a cooling step for restoring the elongation of said wafer;
and
a second exposure step for exposing said wafer, said second exposure is 70 to 60% of the total exposure.

4 more elements

Dependencies are inferred from the claim text.

Method, equipment, and recording medium for controlling exposure accuracy

Life of this patent

Method, equipment, and recording medium for controlling exposure accuracy

Life of this patent

Abstract

Claims4