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Use of CF4-RIE to Improve Polymer Adhesion to Polymer And Metal Adhesion to Polymer

IP.com Disclosure Number: IPCOM000120841D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Bedetti, FV: AUTHOR [+4]

Abstract

In thin film redistribution (TFR) the adhesion of polyimdide (PI) to the organosilicon barrier hexamethyldisilazane [HMDS(N)] is poor. This problem can be solved by the use of carbon tetrafluoride reactive ion etch (CF4-RIE) to remove the HMDS(N) layer. The residual Si (silicon) from HMDS becomes incorporated in the sub-surface so as to provide a surface to which copper (Cu) and PI are better adhered.

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Use of CF4-RIE to Improve Polymer Adhesion to Polymer And Metal Adhesion
to Polymer

      In thin film redistribution (TFR) the adhesion of
polyimdide (PI) to the organosilicon barrier hexamethyldisilazane
[HMDS(N)] is poor.  This problem can be solved by the use of carbon
tetrafluoride reactive ion etch (CF4-RIE) to remove the HMDS(N)
layer.  The residual Si (silicon) from HMDS becomes incorporated in
the sub-surface so as to provide a surface to which copper (Cu) and
PI are better adhered.

      Plasma polymerized organosilicone polymer films have trace
amounts of oligomeric and/or monomeric moieties which have a low
enough boiling point that they are volatilized during further
processing.  This causes loss in adhesion in interfaces where the
organosilicone is present.  This may be due to divinylsiloxane,
hexamethyldisilazane, hexamethyldisiloxane or any other
organosilicone monomer volatile enough for plasma polymerization.
The polymer may be any used as an electrical insulator in the
semiconductor industry such as PMDS-ODA (pyromellitic
dianhydride-oxydianiline), BTDA-MDA (benzophenone tetracarboxylic
dianhydride-methylene dianiline), etc.  The metal may be any metal
used for making the electrical wiring in the semiconductor, such as
Cu, Cr (chromium), Ti (titanium), Ni (nickel), etc.

      Samples were made for ESCA (electron spectroscopy for chemical
analysis) to assess the changes in surface chemistry and for peel
testing to quantify the adhesion improvement achieved by the removal
of the HMDS(N) layer by CF4-RIE.  The results are as follows:

      PMDS-ODA      HMDS(N)        After CF4-RIE
Carbon            77%           46%               21%
Nitrogen           7%           12%                2%
Oxygen            16%           12%               48%
Silicone           ...