Browse Prior Art Database

In Situ Beam and Software Analysis

IP.com Disclosure Number: IPCOM000047521D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gillespie, SJ: AUTHOR

Abstract

This article describes a technique for performing an in-line non-destructive evaluation of the pattern writing of an E-beam lithography system. Evaluation of an E-beam system and its software can be performed by analyzing the output rectangles of the E-beam system. Such an analysis can be done non-destructively by using a double layer resist combination wherein the two resists are selected to have a difference in sensitivity with the lower layer having a higher sensitivity. A pattern can be exposed so that the image of each spot is "burned" into the higher sensitivity resist in a way that it can be clearly visible under an optical microscope. Subfield and rectangle boundaries as well as spot count can be determined in large exposure areas.

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In Situ Beam and Software Analysis

This article describes a technique for performing an in-line non-destructive evaluation of the pattern writing of an E-beam lithography system. Evaluation of an E-beam system and its software can be performed by analyzing the output rectangles of the E-beam system. Such an analysis can be done non- destructively by using a double layer resist combination wherein the two resists are selected to have a difference in sensitivity with the lower layer having a higher sensitivity. A pattern can be exposed so that the image of each spot is "burned" into the higher sensitivity resist in a way that it can be clearly visible under an optical microscope. Subfield and rectangle boundaries as well as spot count can be determined in large exposure areas. In one embodiment of this invention the top resist layer consists of a positive, diazo resist layer, approximately 0.4 mm thick with a sensitivity range of 10-20 m Coulombs/cm2 . The lower resist layer, next to the semiconductor body to be imaged, consists of a positive resist such as PBS (polybutene -1 sulfone), approximately 0.4 mm thick and with a sensitivity of about 0.8 m Coulomb/cm2 . Upon exposure of the system at 20 m Coulombs/cm2, the image of each spot is burned into the higher sensitivity PBS layer. This pattern is then compared with what is expected from the input algorithm of the system. For wafers that include densely patterned areas, a large exposure box with subfield boundarie...