Browse Prior Art Database

Mask to Wafer Alignment System

IP.com Disclosure Number: IPCOM000079908D
Original Publication Date: 1973-Sep-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Feder, R: AUTHOR [+3]

Abstract

X-rays are used in combination with a fluorescent material to accomplish the precise alignment of two objects. The system is especially useful in the alignment of shadow masks with semiconductor materials in x-ray exposure systems.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Mask to Wafer Alignment System

X-rays are used in combination with a fluorescent material to accomplish the precise alignment of two objects. The system is especially useful in the alignment of shadow masks with semiconductor materials in x-ray exposure systems.

Shadow mask 1 having a desired pattern of areas, which are transparent to exposing radiation to permit patternwise exposure of resist layer 2 on semiconductor wafer 3, is aligned with wafer 3 using x-rays. Mask 1 has alignment patterns 4 which permit the passage of small beams of x-rays, for example, one micron in diameter. Wafer 3 has incorporated on its underside appropriate patterns of fluorescent or phosphorescent material, such as four dots
5. The dots can be placed by ion implantation, evaporation, sputtering, photodeposition or other suitable technique.

Light detectors 6 for each pattern of fluorescent or phosphorescent material, with appropriate optics such as lenses 7 and mirrors 8 so that the x-rays do not interfere with the light measurements, are placed beneath wafer 3. The alignment x-rays pass through alignment patterns 4, wafer 3 and strike the complimentary dots 5. The light from dots 5 are focused by the optics on detectors 6. The relative position of mask 1 and wafer 3 is then adjusted until the light measurements indicate that they are properly aligned.

1

Page 2 of 2

2

[This page contains 1 picture or other non-text object]