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Compensating for Linear Distortion Effects in X-Ray Lithography

IP.com Disclosure Number: IPCOM000102505D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Wagner, D: AUTHOR

Abstract

This article describes a method of compensating defects, caused by linear distortion, utilizing the thermal expansion of the mask ring.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Compensating for Linear Distortion Effects in X-Ray Lithography

       This article describes a method of compensating defects,
caused by linear distortion, utilizing the thermal expansion of the
mask ring.

      Linear distortion effects, unless compensated for, limit X-ray
lithography by overlay to a minimum line width of about 0.6 mm.

      The figure shows a conventional mask for X-ray lithography.  A
PYREX* ring provides the silicon membrane mask with the necessary
mechanical stability.  The PYREX ring is replaced by a planar silicon
wafer.  By photolithographic methods, conductive lines and a
thermocouple element, forming a heating system, are provided on the
back of the silicon wafer.

      Heating the edge of the membrane mask in a controlled manner
causes the silicon to expand, compensating for the linear distortion
occurring in the exposure step.

      The described method utilizes the high thermal conductivity of
silicon (1.5 W/cm K) which is nearly five times higher than that of
high-grade steel.  Thus, the heat is rapidly exchanged, with the mask
temperature remaining constant.

                            (Image Omitted)

      Controlling the mask temperature within a value of & 0.05o
yields a compensation accuracy of - 7 nm.
*  Trademark of Corning Glass.