Detection of an end point of polishing a substrate
AssigneeDainippon Screen Mfg. Co., Ltd.
InventorsJunichi Shiomi, Hiroki Fujimoto, Eiji Nishihara, Atsushi Imamura
Life of this patent
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Abstract
A two-dimensional image of a substrate surface targeted for polishing is periodically picked up, and the image is analyzed to obtain an entropy H1, H2 of the two-dimensional image. An end point of polishing is then determined according to the entropy H1, H2. Alternatively, other image characteristic value such as a difference statistic of the image may be employed instead of the entropy H1, H2.
Claims15
A device for detecting an end point of polishing of a substrate, comprising:
- a camera configured to obtain a two-dimensional image of a substrate surface targeted for polishing;
- an image characteristic value calculator configured to calculate a characteristic value for the two-dimensional image by analyzing the two-dimensional image;
- and
- a polishing end point determinator configured to determine an end point of polishing of the substrate according to the image characteristic value.
A method for detecting an end point of polishing of a substrate, comprising the steps of,
- (a) obtaining a two-dimensional image of a substrate surface targeted for polishing;
- (b) calculating a predetermined characteristic value for the two-dimensional image by analyzing the two-dimensional image;
- and
- (c) determining an end point of polishing of the substrate according to the image characteristic value.
A computer program product for detecting an end point of polishing of a substrate, comprising:
- a computer readable medium;
- and
- a computer program stored on the computer program medium, the computer program including:
- a first program for causing a computer to obtain a two-dimensional image of a substrate surface targeted for polishing;
- a second program for causing the computer to calculate a predetermined characteristic value for the two-dimensional image by analyzing the two-dimensional image;
- and
- a third program for causing the computer to determine an end point of polishing of the substrate according to the image characteristic value.
Dependencies are inferred from the claim text.