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Controlling Etching Conditions of Silicon Nitride Si(3)N(4)

IP.com Disclosure Number: IPCOM000077430D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Miller, GJ: AUTHOR [+4]

Abstract

The etching conditions for the boiling phosphoric acid etch of silicon nitride layers on semiconductor wafers are maintained at nearly constant temperature and acid concentration, to provide improved etch rate control. This is accomplished by a workpiece insertion and removal system, which provides an atmospheric interlock so that the reaction chamber is not opened to the atmosphere.

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Controlling Etching Conditions of Silicon Nitride Si(3)N(4)

The etching conditions for the boiling phosphoric acid etch of silicon nitride layers on semiconductor wafers are maintained at nearly constant temperature and acid concentration, to provide improved etch rate control. This is accomplished by a workpiece insertion and removal system, which provides an atmospheric interlock so that the reaction chamber is not opened to the atmosphere.

Etch chamber 1 (Fig. 1) contains a boiling phospheric acid etch bath in lower portion 2 and is fitted with a reflux condenser 3. The workpieces to be etched are placed in a quartz boat 4 in outer chamber 5 through outer door 6, with sliding door 7 in the closed position. Outer door 6 is closed, door 7 is opened and holder 4 is inserted into platform 8 with pushrod 9. Door 7 is closed and boat 4 is lowered by rod 10 on platform 8 into the etchant. The workpieces are removed at the end of the cycle by reversing the above procedure.

Alternately, etch chamber 11 (Fig. 2). equipped with reflux condenser 12, has an interlock system including a sliding cartridge workpiece holder 13, which is adapted to move vertically in rectangular guide walls 14. End wall 15 of holder 13 acts to close chamber 11, when inserting or removing workpiece 16 from holder 13. The workpiece is immersed in the etchant bath which is contained in the bottom portion of chamber 11, by moving holder downward until end wall 17 of holder 13 is against the top of...