Browse Prior Art Database

Molybdenum Evaporation Mask Under Constant Tension

IP.com Disclosure Number: IPCOM000101066D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 113K

Publishing Venue

IBM

Related People

Ganzer, GF: AUTHOR [+4]

Abstract

A fixture alteration is described in this article which overcomes a part slippage problem encountered with existing tooling during the alignment of a molybdenum mask to a semiconductor wafer.

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Molybdenum Evaporation Mask Under Constant Tension

       A fixture alteration is described in this article which
overcomes a part slippage problem encountered with existing tooling
during the alignment of a molybdenum mask to a semiconductor wafer.

      The time allotted for aligning a molybdenum mask to a
semiconductor wafer with existing tooling is considerably greater
than necessary due to slippage of the wafer during alignment.  By
altering the present fixture to place the molybdenum mask under
tension during alignment, backlash (a major contributor to the
slippage) is removed, allowing the normal alignment time to be cut in
half.

      Tooling used in C-4 (controlled-collapse-chip connection)
connector assembly is illustrated in Fig. 1. Shown in the photograph
from left to right are: the top ring 1; molybdenum evaporation mask
2; wafer 3; spring 4; bottom ring 5 and spring clips 6 for holding
the assembly together. Fig. 2 shows a photo of the original mask
alignment head which employs two 2 fixed locating pins 1 and 2.  An
improved mask alignment head (top view) is shown in the photo of Fig.
3.  Only one movable locating pin 3 is now used in order to hold the
molybdenum mask under tension. Backlash is removed by use of this
fixture when aligning the wafer to the molybdenum mask.  The Fig. 4
photo shows the locating pin 3 in the stationary position location,
with the slide lever 4 to the right position.  Fig. 5 illustrates the
locating pin (#) in t...