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Multilayer X-Ray Mask Substrate

IP.com Disclosure Number: IPCOM000037856D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-30
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bassous, E: AUTHOR [+3]

Abstract

Disclosed is a novel multilayer structure for use as an x-ray mask substrate. The structure consists of a boron-doped silicon membrane sandwiched between thin silicon nitride layers that are deposited by low pressure chemical vapor deposition (LPCVD). This 3-layer structure has many material and structural attributes which offer many advantages over conventional boron-doped silicon membranes. Silicon nitride films are smooth, hard, transparent, and physically and chemically stable at high temperatures. Silicon nitride technology is well-established and the films are easily processed by standard techniques.

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Multilayer X-Ray Mask Substrate

Disclosed is a novel multilayer structure for use as an x-ray mask substrate. The structure consists of a boron-doped silicon membrane sandwiched between thin silicon nitride layers that are deposited by low pressure chemical vapor deposition (LPCVD). This 3-layer structure has many material and structural attributes which offer many advantages over conventional boron-doped silicon membranes. Silicon nitride films are smooth, hard, transparent, and physically and chemically stable at high temperatures. Silicon nitride technology is well- established and the films are easily processed by standard techniques.

Advantages of this 3-layer membrane are: 1. The structural stability of the silicon membrane is enhanced by coating and sealing surface imperfections with the strongly adherent nitride films. 2. The nitride film is optically transparent and thus clear windows can be defined inside or outside the membrane region for alignment purposes. Holes in the surface of the silicon wafer are avoided, and thus processing is simplified. 3. Refractory, x-ray absorbers such as tungsten, molybdenum, titanium, and platinum, can be deposited and processed at high temperature on nitride-coated silicon surfaces. LPCVD silicon nitride is an excellent diffusion barrier to metal, silicon and boron impurities. 4. The tensile stress of the 3-layer laminated structure can be adjusted by varying the thickness and deposition conditions of the nitride film....