Applying dimensional reduction to spectral data from polishing substrates

Patent metadata

Field	Value
Publication number	US-10086492-B2
Application number	US-201715818366-A
Country	US
Kind code	B2
Filing date	Nov 20, 2017
Priority date	Oct 25, 2013
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A plurality of spectra reflected from one or more substrates at a plurality of different positions on the one or more substrates are represented in the form of a first matrix, and the first matrix is decomposed into products of at least two component matrixes of a first set of component matrixes. The dimensions of each of the at least two component matrixes is reduced to produce a second set of component matrixes containing the at least two matrixes with reduced dimensions.

First claim

What is claimed is:

1. A method of polishing comprising:
polishing a substrate with a rotating polishing pad in a polishing system;
measuring a plurality of spectra of light reflected from the substrate during polishing with an in-situ spectrographic monitoring system, the plurality of spectra represented in the form of a first matrix,
decomposing the first matrix into products of at least two component matrixes of a first set of component matrixes, a first component matrix of the at least two component matrixes providing eigenvectors for the first matrix;
reducing dimensions of each of the at least two component matrixes to produce a second set of component matrixes containing the at least two matrixes with reduced dimensions, the at least two matrixes including the first component matrix with reduced dimensions;
generating a product of the first component matrix with reduced dimensions and a matrix representing one or more spectra; and
controlling the polishing system based on the product.

2. The method of claim 1 , wherein decomposing the first matrix comprises applying singular value decomposition, applying CUR matrix approximation, or applying principal component analysis.

3. The method of claim 1 , comprising generating a characterizing value based on the product, the characterizing value being associated with a property of the substrate, and controlling a polishing operation based on the characterizing value.

4. The method of claim 3 , comprising determining a polishing endpoint for the substrate based on the characterizing value.

5. A computer program product for controlling processing of a substrate, the computer program product tangibly embodied in a non-transitory computer readable media and comprising instructions for causing a processor to:
store a first component matrix that represents eigenvectors generated by decomposing a first matrix formed by a plurality of spectra into at least two component matrixes to produce a second set of component matrixes and reducing a dimension of the at least two component matrixes;
receive, from an in-situ optical monitoring system, a measured spectrum of light reflected from a substrate undergoing processing that modifies a thickness of an outer layer of the substrate;
generate a product of the first component matrix with reduced dimensions and a matrix representing the measured spectrum; and
control a polishing system based on the product.

6. The computer program product of claim 5 , comprising instructions to generate a characterizing value based on the product, the characterizing value being associated with a property of the substrate, and to control the polishing system based on the characterizing value.

7. The computer program product of claim 6 , comprising instructions to determine a polishing endpoint for the substrate based on the characterizing value.

8. A polishing system, comprising:
a rotatable support to hold a polishing pad;
a carrier head to hold a substrate in contact with the polishing pad;
a motor to rotate the support;
an in-situ spectrographic monitoring system configured to measure a spectrum of light reflected from the substrate during polishing; and
a controller configured to
store a first component matrix that represents eigenvectors generated by decomposing a first matrix formed by a plurality of spectra into at least two component matrixes to produce a second set of component matrixes and reducing a dimension of the at least two component matrixes;
receive, from the in-situ spectrographic monitoring system, a measured spectrum of light reflected from a substrate undergoing polishing;
generate a product of the first component matrix with reduced dimensions and a second matrix representing the measured spectrum; and
control the polishing system based on the product.

9. The system of claim 8 , wherein the controller is configured to generate a characterizing value based on the second matrix, the characterizing value being associated with a property of the substrate, and to control the polishing system based on the characterizing value.

10. The system of claim 9 , wherein the controller is configured to determine a polishing endpoint for the substrate based on the characterizing value.

11. The system of claim 8 , wherein the controller is configured to receive measurements of a plurality of spectra of light reflected from a substrate during polishing with the in-situ spectrographic monitoring system, the plurality of spectra represented in the form of a first matrix, decompose the first matrix into products of at least two component matrixes of a first set of component matrixes, a first component matrix of the at least two component matrixes providing eigenvectors for the first matrix, and reducing dimensions of each of the at least two component matrixes to produce a second set of component matrixes containing the at least two matrixes with reduced dimensions.

12. The system of claim 11 , wherein he controller is configured to decompose the first matrix by applying singular value decomposition, applying CUR matrix approximation, or applying principal component analysis.

Assignees

• Applied Materials Inc

Inventors

• David Jeffrey Drue
• Swedek Boguslaw A
• Cherian Benjamin

Classifications

• H10P74/238

  comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement · CPC title

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10P52/402 Primary

  of semiconductor materials · CPC title

• B24B37/013 Primary

  Devices or means for detecting lapping completion · CPC title