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Jet Etching Arrangement

IP.com Disclosure Number: IPCOM000077040D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Alameddine, O: AUTHOR [+2]

Abstract

The jet etching arrangement shown permits the automatic production of large-area transmissive electromicroscopic semiconductor specimens. The etching rate is controlled via the locally variable transmission of infrared light, so ensuring homogeneous etching or reduction over a wide area. The arrangement utilizes the fact that semiconductors have a band gap of about 1 eV between the valence and conduction bands, thus becoming transparent upon being exposed to infrared light of less than 1 eV. To this end, specimen 1 is uniformly scanned by motor 2 above jet 3, as is shown by arrow 4. Focussed light impinges upon specimen 1 to be observed under microscope 13, being directed onto a light detector 7 via semitransparent mirror 5 and imaging system 6.

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Jet Etching Arrangement

The jet etching arrangement shown permits the automatic production of large-area transmissive electromicroscopic semiconductor specimens. The etching rate is controlled via the locally variable transmission of infrared light, so ensuring homogeneous etching or reduction over a wide area. The arrangement utilizes the fact that semiconductors have a band gap of about 1 eV between the valence and conduction bands, thus becoming transparent upon being exposed to infrared light of less than 1 eV. To this end, specimen 1 is uniformly scanned by motor 2 above jet 3, as is shown by arrow 4. Focussed light impinges upon specimen 1 to be observed under microscope 13, being directed onto a light detector 7 via semitransparent mirror 5 and imaging system 6. Mirror 5 must reflect the infrared proportion almost hundred per cent and pass only the proportion necessary for visual observation. Imaging system 6 is a lens or the like. A filter 8 is disposed behind this lens, which chooses the appropriate spectral range. Light detector 7 is linked with amplifier 9 which controls motor 2 via a potentiometer or electronic means 10. In order to ensure that the intensity registered by detector 7 and the actual position of the specimen at a particular time are clearly associated with each other, an infrared opaque diaphragm is placed at position 12 in front of specimen 1 or in front of detector 7 (position 11). so that the motor speed is controlled by the infrared...