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Infrared Filter for Molybdenum Mask Fixture

IP.com Disclosure Number: IPCOM000100725D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Greer, SE: AUTHOR

Abstract

An infrared (IR) filter is utilized during terminal metal preheat to reduce the temperature gradient across very large semiconductor wafers.

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Infrared Filter for Molybdenum Mask Fixture

       An infrared (IR) filter is utilized during terminal metal
preheat to reduce the temperature gradient across very large
semiconductor wafers.

      Large thermal gradients are formed across large semiconductor
wafers during a terminal metal deposition preheat cycle caused by the
IR heat source. To minimize this effect, a stainless steel "drop-in"
screen is utilized with a redesigned molybdenum mask fixture.
Molybdenum mask fixtures are normally used to clamp wafers to
molybdenum masks during terminal metal deposition.

      The "drop-in" IR screen and the mask fixture are shown in the
figures. The modified fixture design uses fixed circular openings
around the periphery of the back plate and a "drop-in" IR screen
which fills the inner diameter section of the back plate. The screen
is designed with a variable number of holes in it. By adding or
removing selected holes, the screen can be fine-tuned to modify the
temperature gradient across the product wafer until the gradient is
nearly flat from the wafer center to outer edge.