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Browse Prior Art Database

Microscope Auto-Focussing System

IP.com Disclosure Number: IPCOM000040693D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Fluegel, J: AUTHOR [+2]

Abstract

This system focusses the field of view of an object under a microscope automatically and provides continual auto-focus while the field of view moves from object to object. In semiconductor integrated circuits manufacture, microscopes are used frequently to inspect circuit chips during fabrication. A disadvantage of microscopes used for inspection is that chips may be damaged or contaminated by the moving stage of the microscope during manual focussing. Also, focussing time reduces manufacturing through. Referring to the figure, this system automatically focusses the microscope during inspection.

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Microscope Auto-Focussing System

This system focusses the field of view of an object under a microscope automatically and provides continual auto-focus while the field of view moves from object to object. In semiconductor integrated circuits manufacture, microscopes are used frequently to inspect circuit chips during fabrication. A disadvantage of microscopes used for inspection is that chips may be damaged or contaminated by the moving stage of the microscope during manual focussing. Also, focussing time reduces manufacturing through. Referring to the figure, this system automatically focusses the microscope during inspection. The system includes a pressure differential switch 1 set at the focal limits of the microscope, a bias control 2 to adjust the focal distance between lenses, if required, and a microprocessor-controlled stepping motor 3 to receive an input from switch 1. Pressure differential switch 1 connects air line 4 to a distance measuring air sensor 5 on microscope lens 6. Stepping motor 3 is mechanically coupled to the microscope manual adjusting system 7. Alternatively, a gas pressure regulator 8 moves stage 9 of the microscope which holds the object 10 being viewed. In operation, if object 10 is beyond the focal limits of the microscope as detected by sensor 5 operating switch 1 to turn on, the stepping motor control 11 causes motor 3 to move either the microscope lens 6 or the stage 9 until object 10 is within the predetermined focal limits as de...