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:
Feb. 29, 2000
Filed:
Jan. 07, 1999
Kun-Yi Liu, Taina, TW;
Taiwan Semiconductor Manufacturing Company, Hsin-Chu, TW;
Abstract
During the course of manufacturing an IC, the thickness of the photoresist layer varies. In the presence of multiple steps, the difference between the maximum photoresist thickness and the minimum thickness can be quite substantial. It is sometimes the case that the minimum thickness is insufficient in some spots for proper exposure of the resist to be possible. The presence of such spots is detected by means of a monitor in the form of an optical mask comprising a group of lines whose width is close to the critical dimension together with an isolated line of similar width and a second, wider, isolated line. A photoresist image of the process monitor is formed in the kerf for each of the layers that is deposited, with the mask being shifted by about half its length between successive depositions. This ensures that a step is formed between successive layers so that if the photoresist layer is too thin at some point this will be reflected in the monitor. By measuring the widths of lines in the monitor, both in the photoresist image and in the subsequent etched image, the presence of regions where the photoresist is of less than adequate thickness can be inferred from the narrowing of the lines relative to their widths in the original optical monitor mask.