Browse Prior Art Database

Liquid Enhanced Vacuum Chuck for Flattening Wafers

IP.com Disclosure Number: IPCOM000121423D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 53K

Publishing Venue

IBM

Related People

Carr, J: AUTHOR [+4]

Abstract

Disclosed is a vacuum chuck for holding semiconductor wafers where the wafer can be flattened with a higher pressure than the normal one atmosphere used in such chucks. The pressure can be applied with a gas, or with a liquid.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 79% of the total text.

Liquid Enhanced Vacuum Chuck for Flattening Wafers

      Disclosed is a vacuum chuck for holding semiconductor wafers
where the wafer can be flattened with a higher pressure than the
normal one atmosphere used in such chucks.  The pressure can be
applied with a gas, or with a liquid.

      A vacuum chuck 1 as known in the art is connected to a vacuum
line 2 with a connection 3.  A wafer 4 is placed on the flat upper
surface of chuck 1.  In the process of manufacturing semiconductor
wafers, the various materials deposited on wafer 4 cause it to warp
and not contact the upper surface of chuck 1 when vacuum is drawn by
tube 2. Too much air passes between wafer 4 and chuck 1 to draw down
wafer 4 to flatten it against chuck 1.  If, however, a lid 5
connected to a fluid supply through tube 6 and connector 7 is held
down with a force 8 so that the o-ring seal 9 contacts chuck 1, more
pressure can be exerted on wafer 4 to flatten it.  If the fluid is a
liquid, the viscosity of the liquid is much greater than that of air,
and the pressure differential across the wafer is much greater than
when normal air is used.  If a gas is used as the fluid, the pressure
is also much greater, and the wafer is flattened regardless of the
leaks between chuck 1 and wafer 4.  Once the wafer is flat, there are
no more leaks, and the 1 atmosphere pressure might be sufficient to
hold the wafer 4 flat against the chuck 1.  The lid 4 can then be
removed, and the wafer 4 is now flat enough...