Browse Prior Art Database

Cross Linking in Electron Beam Positive Resist Polymer

IP.com Disclosure Number: IPCOM000079553D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Needham, CD: AUTHOR

Abstract

For an electron beam positive resist polymer undergoing chain scissioning during irradiation, the speed is given by the ratio of the chain scission efficiency factor "p" to the incident electron dosage "D" (in microcoulombs/cm/2/). Cross-linking of the polymer is detrimental to the process, since it decreases the rate of dissolution of the exposed polymer. The speed and extent of cross-linking may be determined from the gel permeation chromatogram (GPC) of the polymer before and after exposure.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 87% of the total text.

Page 1 of 2

Cross Linking in Electron Beam Positive Resist Polymer

For an electron beam positive resist polymer undergoing chain scissioning during irradiation, the speed is given by the ratio of the chain scission efficiency factor "p" to the incident electron dosage "D" (in microcoulombs/cm/2/). Cross- linking of the polymer is detrimental to the process, since it decreases the rate of dissolution of the exposed polymer. The speed and extent of cross-linking may be determined from the gel permeation chromatogram (GPC) of the polymer before and after exposure.

The number, weight, and Z average degrees of polymerization are calculated from the GPC by: X(n) = (b/M(0)) [sigma(j) c(j)/A(j)]/-1/ X(w) = (b/M(0)) sigma(j) C(j) A(j) X(z) = (b/M(0)) [sigma(j) C(j) A/2/(j)/ sigma(j) C(j) A(j)] where b is the GPC conversion factor (in amu/angstrom) of the polymer, M(0) is the molecular weight of the polymer repeat unit, and the concentrations C(j) of fraction j (with extended chain length A(j)) are normalized to the condition sigma(j) C(j) = 0.

Chain scissioning and cross-linking change both the number and weight averages of the molecular weight distribution. Let X(n), X(w) and X(z) denote the averages of the distribution of the original polymer, and let X(n) and X(w) denote the averages of the flood exposed polymer. Then the chain scissioning efficiency "p" and the cross-linking efficiency "r" are given by the simultaneous solution of the equations: p = 1 over X'(n) (1 - r X(n)) - 1...