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Method of Producing a Thin Transferable Polymer Membrane

IP.com Disclosure Number: IPCOM000047682D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Bayer, T: AUTHOR [+5]

Abstract

The polymer membrane is formed on a thin silicon substrate which is removable by etching. The thin silicon substrate is a thinned region 2 of a silicon wafer 1. The substrate is produced by highly boron doping silicon wafer 1 from one surface 3, forming a thin P-doped layer 4 and selectively thinning wafer 1 from its other surface 5. For this purpose, an etchant, such as an aqueous pyrocatechol/ethylene diamine mixture is used which etches the bulk of the silicon but not highly P-doped silicon, so that etching stops when the etch front reaches layer 4. The polymer membrane 7 is formed by applying a solution of a polymer precursor, such as polyamic acid, onto surface 3 of wafer 1, followed by removal of the solvent during a curing cycle. Optionally, a structure, such as a metal pattern, may be produced on the polymer membrane.

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Method of Producing a Thin Transferable Polymer Membrane

The polymer membrane is formed on a thin silicon substrate which is removable by etching. The thin silicon substrate is a thinned region 2 of a silicon wafer 1. The substrate is produced by highly boron doping silicon wafer 1 from one surface 3, forming a thin P-doped layer 4 and selectively thinning wafer 1 from its other surface 5. For this purpose, an etchant, such as an aqueous pyrocatechol/ethylene diamine mixture is used which etches the bulk of the silicon but not highly P-doped silicon, so that etching stops when the etch front reaches layer 4. The polymer membrane 7 is formed by applying a solution of a polymer precursor, such as polyamic acid, onto surface 3 of wafer 1, followed by removal of the solvent during a curing cycle. Optionally, a structure, such as a metal pattern, may be produced on the polymer membrane. Finally, thinned region 2 is removed, for example, by reactive ion etching, during which polymer membrane 7 is exposed but not attacked in the tub-shaped recess 6. Subsequently, the part of membrane 7, which bridges the hole in wafer 1, is ready for transfer.

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