Process End Point Detection Measurement Test Site
Original Publication Date: 1978-Jan-01
Included in the Prior Art Database: 2005-Feb-20
As the dimension of a product decreases in large-scale integration, the corresponding dimensions of the test site, for detecting the end point of a process step, decrease, thereby decreasing the signal-to-noise ratio of the test signal and reducing the accuracy of the end-point detection. It has been found that the dimensions of the test site can be made larger than the product dimensions and improve the accuracy of the end-point detection by improved signal-to-noise. This is accomplished by a test site consisting of a plurality of triplet cells which are larger then product cells, but simulate product dimensions. The cells are arranged on the test site so that the scanning beam sees the same average pattern no matter where the beam is directed on the site.