Method of endpoint detection of plasma etching process using multivariate analysis
US9330990B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 2013 |
| Grant date | May 3, 2016 |
| Priority date | — |
| Expiry date | Nov 9, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/67069
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a method for determining an endpoint of an etch process using optical emission spectroscopy (OES) data as an input. Optical emission spectroscopy (OES) data are acquired by a spectrometer attached to a plasma etch processing tool. The acquired time-evolving spectral data are first filtered and demeaned, and thereafter transformed into transformed spectral data, or trends, using multivariate analysis such as principal components analysis, in which previously calculated principal component weights are used to accomplish the transform. A functional form incorporating multiple trends may be used to more precisely determine the endpoint of an etch process. A method for calculating principal component weights prior to actual etching, based on OES data collected from previous etch processing, is disclosed, which method facilitates rapid calculation of trends and functional forms involving multiple trends, for efficient and accurate in-line determination of etch process endpoint.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.