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Chemical Mechanical Wafer Edge Contouring

IP.com Disclosure Number: IPCOM000087356D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Free, TB: AUTHOR

Abstract

It has been found that semiconductor edge contouring reduces wafer edge damage during handling, and the tendency of the wafer edge to fracture or "chip".

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Chemical Mechanical Wafer Edge Contouring

It has been found that semiconductor edge contouring reduces wafer edge damage during handling, and the tendency of the wafer edge to fracture or "chip".

Semiconductor substrate 1 is mounted on vacuum chuck 2, and all processing is done within enclosing chamber 3. Substrate 1 is rotated by rotating vacuum chuck 2. Fluid layer 4, of an appropriate etchant, is flowed across material 5, and the substrate-vacuum chuck unit is lowered into contact with material 5. Pressure controls the amount of substrate edge 6 which contacts material 5. The shape of rigid plate 7 controls the shape of the contour developed on substrate edge 6. Material 5 is an acid-resistant cloth, such as "fluorocarbon felt". Fluid layer 4 is a suitable etchant for the substrate. For silicon substrates, acid combinations of HF/HNO(3), such as "1:250" (HF:HNO(3)), or combinations of HNO(3)/Acetic Acid/HF, such as 8:3:1, 5:2:1, or 3:2:1 are used. Strong bases such as KOH or NaOH could also be used. The choice of fluid layer 4 is determined by desired etch rate and surface finish. Rigid plate 7 can be rotated, oscillated, or stationary. Angle Theta determines some of the geometrical aspects of the contoured edge.

The contouring process is inserted into the fabrication process flow immediately prior to the chemical damage-removal step (chemical-thinning or, if this is not done, chemical-mechanical polishing). In this way, any blemishes on the substrate surface...