Browse Prior Art Database

X-ray Mask/Membrane Fabrication

IP.com Disclosure Number: IPCOM000040877D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+2]

Abstract

Lithographic x-ray masking membranes in silicon wafers are constructed with greater strength, smoother surfaces and selective accurate thickness by using ion implantation of buried dielectric layer as an etch stop.

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X-ray Mask/Membrane Fabrication

Lithographic x-ray masking membranes in silicon wafers are constructed with greater strength, smoother surfaces and selective accurate thickness by using ion implantation of buried dielectric layer as an etch stop.

Referring to the Fig., single crystal silicon wafer 1, having an original surface 2 is subjected to ion implantation to form buried dielectric layer 3, such as silicon dioxide or silicon nitride, after annealing. This leaves defect-free silicon layer 4 above the dielectric layer. The depth and width of dielectric layer 3 is controlled by selective masking, i.e., tungsten, or varying implantation energies. The wafer is then etched with the buried dielectric serving as an etch stop. The back side 5 of the wafer is completed in the usual manner.

Thickness of the membranes can also be varied by epitaxially grown silicon 6 on original surface 2 by thermal oxide masking of alignment membranes. Active silicon devices can be built onto the surface of the mask for x-ray diagnostics, and patterning of the "active" or membrane side of the wafer is accomplished by anisotropic etching.

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