Method and system for endpoint detection
A method and system are presented for monitoring a process sequentially applied to a stream of substantially identical articles by a processing tool, so as to terminate the operation of the processing tool upon detecting an end-point signal corresponding to a predetermined value of a desired parameter of the article being processed. The article is processed with the processing tool. Upon completing the processing in response to the end-point signal generated by an end-point detector continuously operating during the processing of the article, integrated monitoring is applied to the processed article to measure the value of the desired parameter. The measured value of the desired parameter is analyzed to determine a correction value thereof to be used for adjusting the end-point signal corresponding to the predetermined value of the desired parameter for terminating the processing of the next article in the stream.
1. A process control system for use with a processing tool which is to be sequentially applied to a stream of substantially identical articles, the system comprising:
an end-point detector operable within a working area defined by the processing tool when said processing tool is applied to the article;
an integrated monitoring tool installed with said processing tool and operable outside said working area for measuring a thickness of the article; and
a control unit connected to the end-point detector and to the integrated monitoring tool, the control unit including processing and computational intelligence responsive to data coming from the end-point detector and to the measured data coming from the integrated monitoring tool, for analyzing these data and generating a signal for terminating the processing of the article.
2. The system according to claim 1 , wherein said end-point detector utilizes optical means.
3. The system according to claim 1 , wherein said stream of the articles are semiconductor wafers.
4. The system according to claim 1 , wherein said integrated monitoring tool is capable of spectrophotometric measurements.
5. The system according to claim 1 , wherein said processing is CMP.
6. The system according to claim 2 , wherein said end-point detector is capable of spectrophotometric measurements.