Browse Prior Art Database

Dual Microscope Semiconductor Wafer Inspection Machine

IP.com Disclosure Number: IPCOM000034660D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 5 page(s) / 171K

Publishing Venue

IBM

Related People

Gasper, A: AUTHOR [+4]

Abstract

A technique is described whereby a dual microscope inspection machine provides a semi-automatic means of detecting and recording particles and imperfections appearing on the surface of semiconductor wafers. The machine consists of four major components: a wafer handler, a vibration isolation bench assembly, a dual microscope plate assembly, and electrical control cabinet assembly. In the semiconductor wafer fabrication process, inspection and measurement procedures are used to maintain product quality. The machine described herein is designed to aid an operator in this inspection process.

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Dual Microscope Semiconductor Wafer Inspection Machine

A technique is described whereby a dual microscope inspection machine provides a semi-automatic means of detecting and recording particles and imperfections appearing on the surface of semiconductor wafers. The machine consists of four major components: a wafer handler, a vibration isolation bench assembly, a dual microscope plate assembly, and electrical control cabinet assembly. In the semiconductor wafer fabrication process, inspection and measurement procedures are used to maintain product quality. The machine described herein is designed to aid an operator in this inspection process. Special lighting is incorporated to illuminate the surface of the wafer so that with the use of both high- and low-powered microscopes defects will be highlighted, enabling the type and coor

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dinate location of the defect to be automatically recorded. The machine incorporates a mechanism to automatically feed the wafers to the inspection station, indexing the wafer for viewing and an electronic procedure for classifying and recording the defects. The machine, as shown in Fig. 1, consists of three basic sections: (1) wafer handling section, as shown in Fig. 1A; (2) vibration isolation bench and dual microscope plate assembly section, as shown in Fig. 1B; and (3) electrical control cabinet assembly section, as shown in Fig. 1C. The wafer handling section consists of wafer cassette 10, as shown in Fig. 2, which can hold up to twenty-five wafers. The wafers are loaded by the operator into cassette 10 and is placed onto elevator 11.

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The machine reads the cassette serial number so as to enable the computer, located in the electrical control cabinet, to download the process information data regarding the specific wafer type under test. Elevator 11 raises and lowers cassette 10 so as to enable the pickup arm in orbitron 12 to pick up the desired wafer to be tested. Orbitron 12 has the ability to rotate, such that after the wafer is picked up from cassette 10, under vacuum control, orbitron 12 will rotate so as to insert the wafer into orientor 13. Orientor 13 is designed to locate the center of the wafer through the use of a light beam coinciding with a V-notch on the perimeter of the wafer. At the completion of the orientation operation, orbitron 12 picks

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up the oriented wafer. Propeller 14 interfaces with orbitron 12 within the wafer handler so as to propel the wafer into the inspection station. Propeller 14 has a short Z-motion used to lift the wafers. When orbitron 12 brings a wafer to propeller 14, propeller 14 rotates to face orbitron 12 which

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extends a pick up blade so as to transfer the wafer. Propeller 14 vacuum is turned on and orbitron 12 vacuum is turned off. Propeller 14 performs a rotation to face chuck assembly 15, as shown in Fig. 3.

Chuck assembly 15 is mounted on stage assembly 16 so as to accurately position the wafer und...