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:
Nov. 23, 1993
Filed:
Sep. 10, 1991
Akira Kawai, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
Alignment marks capable of providing accurate registration signals even if substrate surface is rough and capable of effectively preventing degradation of registration accuracy due to unevenness of a surface of a resist film, and method of forming such alignment marks are disclosed. The alignment marks include flat portions 1a having high vertical reflectance serving as the alignment mark portions and rough portions 1b, formed spaced apart from each other by a prescribed distance on a surface of a substrate 1 by irradiation of laser beam 50. Therefore, fluctuation of height of a surface of a resist film 13 formed on the alignment marks with an upper layer film posed therebetween can be prevented, and in turn, degradation of registration accuracy of masks due to the unevenness of the resist film surface can be effectively prevented. Even if the surface of the substrate is rough, flat portions 1a providing accurate signal waveforms can be easily formed.