Browse Prior Art Database

Mann 4800 Exposure Field Uniformity Test

IP.com Disclosure Number: IPCOM000061154D
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gut, GM: AUTHOR

Abstract

Uniform illumination intensity of light within the whole illumination field of a step and repeat camera is important for proper execution of photolithographic processes on semiconductor wafers. This article summarizes a method of locating and measuring large and small scale nonuniformities of illumination within an exposure field.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 92% of the total text.

Page 1 of 1

Mann 4800 Exposure Field Uniformity Test

Uniform illumination intensity of light within the whole illumination field of a step and repeat camera is important for proper execution of photolithographic processes on semiconductor wafers. This article summarizes a method of locating and measuring large and small scale nonuniformities of illumination within an exposure field.

The technique uses measurements of photoresist thickness in an exposure field photographed on a uniformly photoresist coated silicon wafer. The nominal exposure dose for the whole field is chosen such that the photoresist develops away only partially in the developing solution. Measurements are performed with instruments which look at various size areas within the field ranging from very small to large. This permits both large and small scale nonuniformities to be located and measured. The location of a nonuniformity is revealed by microscope inspection as a color variation of the photoresist.

Photoresist thickness measurements are compared to a thickness vs. exposure-dose relationship graph to determine the relative dose of illumination received in the measured area. The photoresist thickness vs. exposure dose graph is generated by exposing a series of fields at various exposure intensities on a photoresist coated wafer which is prepared in the same manner as the test wafer. A thickness of photoresist measurement is performed on each field in a manner which averages out the small thickness varia...