International Business Machines Corporation

Constantino Lapadula

Burn J Lin

Kevin K Chan

Michael Hatzakis

Ernest Bassous

Istvan Lovas

Joseph M Blum

Alan D Wilson

Angela C Lamberti

The method of fabrication of a monolithic silicon membrane structure in which the membrane and its supporting framework are constructed from a single ultra thick body of silicon. The fabrication sequence includes the steps of providing a doped membrane layer on the silicon body, forming an apertured mask on the silicon body, and removal of an unwanted silicon region by mechanical grinding and chemical etching to provide a well opening in the silicon body terminating in the doped membrane.

Monolithic silicon membrane device fabrication process

A photolithographic method wherein a mask is made by pattern exposing and developing a o-quinone diazide sensitized phenol-formaldehyde resist layer, the formed resist mask then being used directly as an exposure mask for a layer of deep ultraviolet (less than 3000A) sensitive resist such as an alkyl methacrylate resist. Since alkyl methacrylate resists are not sensitive to light above 3000A and phenol-formaldehyde resists are opaque to light below 3000A, phenol-formaldehyde resists may be used directly as photoexposure masks for alkyl methacrylate resists using any broad band exposure light source which includes deep ultraviolet. The direct use of a phenol-formaldehyde resist layer as an exposure mask for an alkyl methacrylate resist layer allows more flexible and practical use of resist exposure techniques, including fabrication of an etch resistant mask of high aspect ratio and high resolution without fabrication of an intermediate metallic mask from a material such as chromium.

Method of using a o-quinone diazide sensitized phenol-formaldehyde

In the process of developing exposed photoresist on a substrate, the endpoint in developing away all of the exposed positive photoresist or any other positive resist is detected by exposing a wafer with a predetermined pattern including an optical grating or other special pattern formed in the photoresist upon a test area. In a system employing this concept, a beam is diffracted by the optics of the grating only at a first angle until the resist forming the grating is removed by development. Then a sensor is activated when an angle of reflection is unblocked when the grating disappears. The system is then turned off to stop development by the sensor in an automatic system or, by the operator in a manual system. A double exposure technique is employed to produce the grating or other special pattern.

Resist development control system

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Mahopac, NY, United States of America

Constantino Lapadula