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:
Mar. 11, 1997
Filed:
Feb. 17, 1994
Makiko Mori, Atsugi, JP;
Kunitaka Ozawa, Isehara, JP;
Koji Uda, Yokohama, JP;
Isamu Shimoda, Zama, JP;
Shunichi Uzawa, Tokyo, JP;
Eiji Sakamoto, Sagamihara, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of exposing a wafer to exposure energy such as ultraviolet rays or X-rays through a mask to transfer a pattern of the mask onto the wafer, for example. The temperature of the mask and/or the wafer increases during the exposure operation by absorption of the exposure energy. While the wafer is being exposed, the temperature of the mask and/or the wafer is detected. If the temperature is going to exceed an exposable temperature range determined on the basis of the line width of the pattern to be transferred, the exposure operation is interrupted. Then, the heat accumulated in the mask and/or the wafer is removed. Thereafter, the exposure operation is resumed. This is repeated until the predetermined or required amount of exposure is reached, for one shot. By this, thermal expansion of the mask and the wafer during the exposure operation is prevented to assure the precision of the pattern transfer.