Browse Prior Art Database

INFRARED ALIGNMENT FIXTURE for CHIP WRITER SYSTEM

IP.com Disclosure Number: IPCOM000040182D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 3 page(s) / 60K

Publishing Venue

IBM

Related People

Khoury, HA: AUTHOR

Abstract

This method permits reading chip serial identification markings on the backside of the chips without interfering with chip processing. An infrared detection system reads the markings on the back by focusing on the front of the wafer. (Image Omitted) In semiconductor processing one must provide identification (ID) markings on chips. A chip writing system is used to write characters on the backside of electrically tested good chips. To prevent high thermal impedance between the chip and its corresponding module position, the characters 1 (Fig. 1) are written in the very corners of the chip 2, placed within a positional tolerance of + 20 m relative to the chip corners on the back 3 of the chip.

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INFRARED ALIGNMENT FIXTURE for CHIP WRITER SYSTEM

This method permits reading chip serial identification markings on the backside of the chips without interfering with chip processing. An infrared detection system reads the markings on the back by focusing on the front of the wafer.

(Image Omitted)

In semiconductor processing one must provide identification (ID) markings on chips. A chip writing system is used to write characters on the backside of electrically tested good chips. To prevent high thermal impedance between the chip and its corresponding module position, the characters 1 (Fig. 1) are written in the very corners of the chip 2, placed within a positional tolerance of + 20 m relative to the chip corners on the back 3 of the chip. The positional relationship between the chips on the front side of the wafers and the written characters on the opposite side is maintained to package four 250 m size characters on each corner of the chip with adequate space between the characters to prevent crosstalk in the automatic reading system [1]. It is necessary to prevent characters from spilling over in the forbidden cooling piston zone 4, and characters may not be written on the chip kerf area where they would be destroyed when the wafer is diced.

(Image Omitted)

This development provides an infrared (IR) alignment system to permit the chip writer operator to position the writer accurately and rapidly, to assure the location of the characters precisely on the chip corners. This is done without significant trial and error proce...