Browse Prior Art Database

Deep Trench Etch Gauge

IP.com Disclosure Number: IPCOM000036782D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Harmon, DL: AUTHOR [+2]

Abstract

A membrane is etched alongside or as part of a semiconductor wafer or other substrate in a process of trench etching. Penetration of radiation through the membrane is used to indicate etch endpoint.

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Deep Trench Etch Gauge

A membrane is etched alongside or as part of a semiconductor wafer or other substrate in a process of trench etching. Penetration of radiation through the membrane is used to indicate etch endpoint.

By using a membrane of the same material (or a material having a known relative etch rate) of a thickness which will provide etch- through at the etch depth desired in a material on a semiconductor wafer and detection of radiation penetrating through the membrane, in situ detection of process endpoint is achieved.

Referring to the figure, semiconductor wafer 2 is on support plate 4 in an etching apparatus. A pattern to be etched in semiconductor wafer 2 is defined by a developed pattern in photoresist 6. Also on support plate 4 is membrane 8 having a patterned photoresist 10. Radiation 12, coming from above, is detected by detector 14 when etching has opened holes in membrane 8. If membrane 8 is the same material as that being etched on semiconductor wafer 2, membrane 8 is made having a thickness equal to the desired depth of trenches in semiconductor substrate 2.

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