Browse Prior Art Database

Notched Wafer Alignment System

IP.com Disclosure Number: IPCOM000075163D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Firrester, T: AUTHOR [+2]

Abstract

A measuring system aligns a silicon wafer relative to its crystal lattice for purposes of inspection and/or device fabrication.

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Notched Wafer Alignment System

A measuring system aligns a silicon wafer relative to its crystal lattice for purposes of inspection and/or device fabrication.

The system includes fixture 1 to align the water and an x-ray goniometer 2. Goniometer 2 comprises a collimated x-ray source 3, and a Geiger counter reflected beam detector 4. A beam trap 5 can be provided. Fixture 1 is aligned on the goniometer and fixed into position y by a magnetic block 6. Wafer support block 7 carries two sets of three peripheral alignment pins 8, which are spaced in pairs for accommodating wafers of various diameters. Adjustable notch positioning pin 9 in movable by knob 10. Pin 9 is placed in notch 11 of wafer 12 and knob 10 turned so that datum y-y of wafer 12 is aligned by two pins 8 and pin
9. (Datum y-y being defined as normal to line segment N1-N2, and mutually bisecting Nl-N2 and the angle formed by peripheral tangents at points P2 and P3) Goniometer 2 is set up for a given Bragg angle B and a reflecting angle 2 Theta. X-rays from source 3 are then reflected from the atomic planes d at the edge of wafer 12. Deviations to +/-15 degrees from the Bragg angle can be measured or aligned routinely. The accuracy for this system is 0.01 degree and the 3 precision is +/- 0.01 degree.

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