Browse Prior Art Database

Unambiguous Fiduciary Marks for Wafer Processing

IP.com Disclosure Number: IPCOM000081250D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Harper, JS: AUTHOR [+4]

Abstract

This description relates to the production of alignment lines on semiconductor wafers for registration of the wafers during circuit fabrication.

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

Page 1 of 1

Unambiguous Fiduciary Marks for Wafer Processing

This description relates to the production of alignment lines on semiconductor wafers for registration of the wafers during circuit fabrication.

Previously, alignment lines on a semiconductor wafer produced by reflection could not be easily detected, because of interaction with light reflected from other oxide or photoresist boundaries. As a result of such light interaction, a single alignment line may appear dark or bright, it may appear in duplicate or triplicate, or it may disappear completely. Thus, because there is no known expected signal, automatic wafer alignment is difficult to obtain.

In the present description, the alignment pattern is produced in such a manner that the aforesaid interference effects do not occur. This is accomplished by fabricating the alignment of zero, i.e., black lines. The zero reflectivity lines are produced by fabricating the lines with rough surfaces, so that the incident light is not reflected but is scattered. The rough surface lines are produced by special etching or by writing the lines with a laser beam.

1