The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1994
Filed:
Sep. 29, 1992
Hamid K Aghajan, Stanford, CA (US);
Thomas Kailath, Stanford, CA (US);
The Board of Trustees of the Leland Stanford Junior University, Stanford, CA (US);
Abstract
An image processor employing a camera, frame grabber and a new algorithm for detecting straight edges in optical images is disclosed. The algorithm is based on using a self-organizing unsupervised neural network learning to classify pixels on a digitized image and then extract the corresponding line parameters. The image processor is demonstrated on the specific application of edge detection for linewidth measurement in semiconductor lithography. The results are compared to results obtained by a standard straight edge detector based on the Radon transform; good consistency is observed; however, superior speed is achieved for the proposed image processor. The results obtained by the proposed approach are also shown to be in agreement with Scanning Electron Microscope (SEM) measurements, which is known to have excellent accuracy but is an invasive measurement instrument. The method can thus be used for on-line measurement and control of microlithography processes and for alignment tasks as well.