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. 04, 1997
Filed:
Dec. 13, 1994
Hiroshi Nozue, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A direct patterning method using an electron beam, which-contains first and second steps. In the first step, a first beam of incident electrons accelerated at a first voltage is irradiated to an electron resist film and scanned. The first voltage is set so that the electrons penetrate the resist film to be back-scattered by a semiconductor substrate having an alignment mark and pass through the film again. Secondary electrons generated at the surface of the resist film due to the back-scattered electrons are detected by an electron detector to recognize the alignment mark. In the second step, a second beam of incident electrons accelerated at a second voltage lower than the first voltage is irradiated to the resist film and scanned by reference to the alignment mark to write a given pattern in the resist film. Since the back-scattered electrons from the first beam have sufficiently high energies, they can penetrate the resist film to reach its surface and generate many secondary electrons on the surface of the film. An electric signal produced from the secondary electrons is large in amplitude to increase the S/N, resulting in improvement in alignment accuracy.