Browse Prior Art Database

Process Control Monitor for an E-Beam Lithography Tool

IP.com Disclosure Number: IPCOM000037916D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-30
Document File: 3 page(s) / 100K

Publishing Venue

IBM

Related People

Guillaume, WJ: AUTHOR [+2]

Abstract

A method has been proposed for determining the optimum developing time for resist images exposed on an E-beam lithography tool. The procedure provides a means of monitoring the development of semiconductor wafers in both research and manufacturing operations. It involves the use of a special test structure written by the E-beam tool which contains a broad range of dose increments with the nominal dose found in the center of the array. The structure also contains a trench for resist thickness measurements and an etch bias monitor to measure the growth or shrinkage of the resist after development. (Image Omitted)

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 56% of the total text.

Page 1 of 3

Process Control Monitor for an E-Beam Lithography Tool

A method has been proposed for determining the optimum developing time for resist images exposed on an E-beam lithography tool. The procedure provides a means of monitoring the development of semiconductor wafers in both research and manufacturing operations. It involves the use of a special test structure written by the E-beam tool which contains a broad range of dose increments with the nominal dose found in the center of the array. The structure also contains a trench for resist thickness measurements and an etch bias monitor to measure the growth or shrinkage of the resist after development.

(Image Omitted)

In a conventional operation, a single-dose E-beam fiducial or end-point- detection (EPD) structure is written with a single predetermined dose. Fig. 1 illustrates the resist profile after such a structure is exposed and developed. The dosage is that required to expose the large geometry data, but is not representative of the small geometries, which require more exposure for full development. The single-dose EPD becomes more unreliable as geometry size shrinks and is vulnerable to minute process changes and operator misinterpretation.

The proposed process control monitor contains a staircase of preassigned doses arranged to form a usable scale from its low end to its high end. Fig. 2 illustrates the resist profile after such a structure is exposed and developed. The actual dose required for full develop...