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Clean Method for Contamination Monitoring During the Production of Tungsten Silicide

IP.com Disclosure Number: IPCOM000061245D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Briska, M: AUTHOR [+2]

Abstract

Thinned regions of a silicon wafer with a deposited tungsten silicide layer are decomposed in a decomposition apparatus where volatile silicon fluoride and tungsten fluoride are formed and removed and contaminants are retained and subsequently determined by atomic absorption spectroscopy. The chemicals used and the process for producing the silicide are characterized with regard to purity as a function of the amount of contaminants determined. A silicon wafer with an about 2 mm thick boron-doped surface layer is selectively thinned from the opposite surface with a pyrocatechol solution. Thinning stops at the boron-doped surface layer. A tungsten silicide layer of predetermined thickness is deposited on top of the boron-doped surface layer. Fig.

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Clean Method for Contamination Monitoring During the Production of Tungsten Silicide

Thinned regions of a silicon wafer with a deposited tungsten silicide layer are decomposed in a decomposition apparatus where volatile silicon fluoride and tungsten fluoride are formed and removed and contaminants are retained and subsequently determined by atomic absorption spectroscopy. The chemicals used and the process for producing the silicide are characterized with regard to purity as a function of the amount of contaminants determined. A silicon wafer with an about 2 mm thick boron-doped surface layer is selectively thinned from the opposite surface with a pyrocatechol solution. Thinning stops at the boron- doped surface layer. A tungsten silicide layer of predetermined thickness is deposited on top of the boron-doped surface layer. Fig. 1 is a cross-sectional view of this stage of the method, reference numbers 1, 2, 3 and 4 designating the wafer, the boron-doped surface layer, the thinned regions of the wafer and the silicide layer, respectively. In the next step, the thinned regions 3, having predetermined dimensions, are forced out by means of a quartz rod and transferred to decomposition tube 11 of decomposition apparatus 10, a cross- sectional view of which is shown in Fig. 2. The interior of apparatus 10 has a central bore 12 for inserting tube 11, an angular groove 13 surrounding bore 12, and a free space 14 above the latter and groove 13. A cover 15 is provided fo...