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Photoresist Application Process

IP.com Disclosure Number: IPCOM000075071D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Elijah, LM: AUTHOR [+5]

Abstract

An electrostatic spray coating method for photoresists avoids material waste and variation in coating thickness, which are normally associated with conventional spin costing techniques.

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Photoresist Application Process

An electrostatic spray coating method for photoresists avoids material waste and variation in coating thickness, which are normally associated with conventional spin costing techniques.

Clean, dry silicon wafers are held by vacuum on a pedestal having the same diameter as the wafer. If the wafer surface is an insulator, for example, thermal SiO(2) or sputtered quartz, the pedestal and the associated equipment are grounded. The wafer surface is then either blown with an inert, dry, highly charged ionizing gas or treated with an applicator/charging bar in a dry inert atmosphere, to highly charge the wafer surface. The pedestal is then insulated and the charging apparatus is either moved aside or the pedestal is moved to the coating station.

Oppositely charged surfactant is then sprayed through a highly charged nozzle at a voltage which is chosen depending upon the wafer size and distance. The spraying nozzle, supporting table and the balance of the equipment enclosure are electrically connected so that the charged surfactant is attracted to and deposited upon the oppositely charged wafer surface. When the surfactant layer has dried, the charging and spraying steps are repeated utilizing a charged photoresist solution.

If the wafer surface is conductive then the wafer surface is grounded and the charging step is omitted.

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