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Cleaning Silicon Semiconductor Wafers

IP.com Disclosure Number: IPCOM000074230D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Elijah, LM: AUTHOR

Abstract

Numerous problems arise during photoresist coating, epitaxial deposition, diffusion, etc., that are directly or indirectly attributed to inadequate cleaning techniques. These may be the result of fingerprints, residues, dirt or dust particles due to static or time etc., which result in epitaxial mounds or spikes, outgassing, surface roughness, contamination, inferior photoresist adhesion, scratching of photoresist masks.

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Cleaning Silicon Semiconductor Wafers

Numerous problems arise during photoresist coating, epitaxial deposition, diffusion, etc., that are directly or indirectly attributed to inadequate cleaning techniques. These may be the result of fingerprints, residues, dirt or dust particles due to static or time etc., which result in epitaxial mounds or spikes, outgassing, surface roughness, contamination, inferior photoresist adhesion, scratching of photoresist masks.

Thorough, effective cleaning is accomplished, by first containing the wafers in holders (inert to the cleaning agents and temperatures specified below, for example, quartz or fluorocarbon). Then vapor degreasing in hydrophobic chlorinated hydrocarbon at 165 degrees F by deep vapor immersion, with pure side-well condensate, spraying wafers for five (5) minutes. Remove. Allow to dry. Then immerse in pulsating (25,000 to 30,000 cps) spray of hydrophilic detergent water solution at 140degrees F, at spray pressure that will not cause fracture. Rinse in hot (170degrees F) ultrasonically agitated flowing tap water. Follow with rinse in filtered (less than 5mu particle size) deionized water, till resistance of outflow is greater than about 12 megohms. Remove and blow dry with hot nitrogen in centrifuge. Bake as required for thorough drying. Wafers are now ready for use. If for some reason, undue handling or delay occurs, causing suspicion of contamination, the above steps should be supplemented by cleaning in hydroph...