Browse Prior Art Database

Release Layer for Decal Packages

IP.com Disclosure Number: IPCOM000121009D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Kugel, LE: AUTHOR [+3]

Abstract

In the past, decal packages have been formed on silicon substrates and then the silicon has been etched away. With this process, polymer decals for packaging applications can be fabricated on silicon wafers using a siloxane release layer to form a self-supporting decal and eliminating expensive silicon back-etch processes.

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Release Layer for Decal Packages

      In the past, decal packages have been formed on silicon
substrates and then the silicon has been etched away.  With this
process, polymer decals for packaging applications can be fabricated
on silicon wafers using a siloxane release layer to form a
self-supporting decal and eliminating expensive silicon back-etch
processes.

      Polyimide decals with circuitry can be fabricated easily by
using siloxane-type polymers as a release layer (Fig. 1).  The decals
can be fabricated on silicon wafers, exposed on common lithography
tools and processed.  The finished decal can then be released easily
from the silicon by using siloxane polymers as a release layer.  The
free-standing decal is shown in Fig. 2.  The process is as follows:
Process
1.   Spin 3000 o of poly (dimethyl/siloxane) on a silicon wafer.
2.   Evaporate Cu (to thickness desired); or other suitable metals.
3.   Evaporate Cr (500 o - for polyimide adhesion).
4.   Spin polyimide to thickness desired.
5.   Fabricate Cu or Al circuitry.
6.   Form free-standing decal by pulling.  Cu will release easily
from the siloxane.
Advantages
o    Decals can be fabricated on solid supports, e.g., silicon,
copper invar, polyethylene terephtalate, thick plastics, etc., and
released without wet etch techniques.
o    Bottom layer of Cu can also be patterned.
o    Carrier is reusable and in the case of plastics, the decal may
be heat laminated, similar to a dry la...