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New Silicon Containing Barrier Layer for Packaging Application

IP.com Disclosure Number: IPCOM000107495D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 1 page(s) / 52K

Publishing Venue

IBM

Related People

Babich, ED: AUTHOR [+6]

Abstract

A new polyimide is described which contains phenolic HOfunctional groups and therefore can be silylated using wet or vapor silylation processes. The use of polyfunctional organosilicon compounds with different reactivity allows to incorporate 8-15% wt. of silicon depending on the type of silylating agent chose. This makes it possible to use such silylated polyimide materials as etch barriers during O2 plasma etching. Such materials are much more compatible with polyimide layers compared to polysiloxane type etch barriers.

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New Silicon Containing Barrier Layer for Packaging Application

      A new polyimide is described which contains phenolic
HOfunctional groups and therefore can be silylated using wet or vapor
silylation processes.  The use of polyfunctional organosilicon
compounds with different reactivity allows to incorporate 8-15% wt.
of silicon depending on the type of silylating agent chose.  This
makes it possible to use such silylated polyimide materials as etch
barriers during O2 plasma etching.  Such materials are much more
compatible with polyimide layers compared to polysiloxane type etch
barriers.

      A silylation of the polyamic acid which contains (6F-units)
using bis(dimethylamino)dimethylsilane or hexamethylcyclotrisilazane
as silylating agents in a bath leads to the formation of silicon
containing crosslinked polymer with the structure shown below:

      No damage of PI films occurs during wet or vapor silylation.

      It was found, for example, that a PI containing 20% mol. of
6F-units was coated on an Si-wafer forming a film about 3 um thick,
baked at 90~C/15 min. and then silylated in vapor phase with HMDS at
126~C for 30 min.  The film was etched in O2 plasma at 10 mTorr, 0.2
watt/cm2 for 80 min. Fig. 1 shows kinetics of the etching process
followed by laser interferometer with an average etch rate of 130
A/min. Unsilylated PI, containing 6F units, has an etch rate of about
1000 A/min.
Fig. 1 - Etching characteristics of the silylated 6F-PI (ti...