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Semiconductor Wafer Processing

IP.com Disclosure Number: IPCOM000045071D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Strudwick, TH: AUTHOR [+2]

Abstract

The succession of steps in this process improves the surface characteristics of wafers sliced from a rod of semiconductor crystal. The process steps comprise: 1. Grinding the crystal face to the desired geometry. 2. Using the thus-ground face to longitudinally index the crystal in the wafer-slicing machine. 3. Using the ground surface of the wafer to orient and mount the severed wafer for grinding and polishing the sawn surface. 4. Repeating steps 1 through 3 for each successive wafer.

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Semiconductor Wafer Processing

The succession of steps in this process improves the surface characteristics of wafers sliced from a rod of semiconductor crystal. The process steps comprise: 1. Grinding the crystal face to the desired geometry.

2. Using the thus-ground face to longitudinally index

the crystal in the wafer-slicing machine.

3. Using the ground surface of the wafer to orient and

mount the severed wafer for grinding and polishing

the sawn surface.

4. Repeating steps 1 through 3 for each successive

wafer.

Current methods of slicing thin wafers from a semiconductor with an annular saw with an internal cutting edge has limitations in producing ultra-flat surfaces. Process variability of the I.D. (internal diameter) slicing operation (e.g., blade tension; loading of the diamond cutting edge; changes of the cutting edge throughout blade life; changes in tension characteristics of the blade throughout blade life; etc.) produces surfaces with irregular and non-controllable deviations from planarity.

The irregularities and deviations of the surfaces produced by I.D. slicing are difficult to remove during subsequent shaping and polishing operations. When the sawn surface is vacuum chucked and pressure applied during planetary lapping or polishing, the irregular surface allows the wafer to be distorted so that upon demounting the wafer and relaxation of the distortion, the lapped/polished surface is distorted out of planarity.

If the to be severed wafer is grou...