Browse Prior Art Database

Wafer Identification System

IP.com Disclosure Number: IPCOM000089483D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Herring, RB: AUTHOR [+3]

Abstract

The problems extant in combining a human readable, as well as machine readable, identification part number on semiconductor wafers have plagued the semiconductor industry. There have been numerous instances of such systems requiring expensive and elaborate equipment for the machine-readable portion and/or requiring the human to interpret a code and the like in making such an identification. The system described herein simplifies greatly the problems inherent in such a system while permitting economic equipment fabrication and still retaining human-readable, noncodable formats.

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Wafer Identification System

The problems extant in combining a human readable, as well as machine readable, identification part number on semiconductor wafers have plagued the semiconductor industry. There have been numerous instances of such systems requiring expensive and elaborate equipment for the machine-readable portion and/or requiring the human to interpret a code and the like in making such an identification. The system described herein simplifies greatly the problems inherent in such a system while permitting economic equipment fabrication and still retaining human-readable, noncodable formats.

In accordance with the present system, the semiconductor wafer is processed in a conventional manner using mask technology and photoresist, and may have an identification number or symbol placed on the wafer during the initial processing stages. To this end, and referring first to Fig. 3, a numeral 0 is by suitable masking techniques placed on the wafer along with the two "block bits" A and B having definitive grating line angles therein, notably, as shown, Theta(A) and Theta(B). Assuming five such blocks with grating lines at different angles, a ten-bit code may be formulated, such as illustrated in Fig. 4. For example, the digit 0 is formed of the blocks A and B, the digit 1 is formed of the blocks A and C, and so on, the code being represented in chart form in the drawing such that any two-bit blocks put together will represent one digit.

With more than a single digit identification system, for example, in a three digit scan system, because of the width of the laser spot which is used to...