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Improved Method of Polyimide Polyamic Acid Solution Application and Processing

IP.com Disclosure Number: IPCOM000109398D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 2 page(s) / 94K

Publishing Venue

IBM

Related People

Fredericks, EC: AUTHOR [+3]

Abstract

Polyamic acid and polyimide solutions, spin applied to semiconductor wafers, cured through temperature ranges up to 325~C, and/or baked to get rid of solvents or reaction products, are fast becoming the choice of insulating material over silicon dioxide due to apply costs and tooling costs. (Image Omitted)

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This is the abbreviated version, containing approximately 52% of the total text.

Improved Method of Polyimide Polyamic Acid Solution Application and Processing

       Polyamic acid and polyimide solutions, spin applied to
semiconductor wafers, cured through temperature ranges up to 325~C,
and/or baked to get rid of solvents or reaction products, are fast
becoming the choice of insulating material over silicon dioxide due
to apply costs and tooling costs.

                            (Image Omitted)

      Polyamic acid and/or ECF polyimide solutions, are generally
preferred and applied at near or slightly above room temperature,
generally less than 30~C (centigrade).  These solutions of partially
reacted or fully reacted materials, like amines and pyromelletic
anhydrides, often contain insoluble gels and dirt particles that must
be removed.  The usual treatment of filtration through paper of metal
or polymer filters may not consistently be effective due to filtrate
build up and decreasing filter efficiency, often with undesirable
bubble formation.

      In a novel experiment we have found that heating the polyamic
acid and/or polyimide solution to significantly higher than 30~C will
allow improved filtration and application of these solutions without
altering the desired insulating qualities.  Since the polyamic acid
and/or polyimide solutions are used as an insulating layer between
metal, the films require high viscosities and solids contents to
achieve metal coverage as well as good gap fill capabilities.  Due to
the viscous nature of these materials, true point of use filtration
at wafer dispense has been found unsuccessful.  Offline filtration
has proven to be the only method to date for particulate removal.  It
is accomplished by high pressure, forcing the material through the
filter.  This method creates numerous air bubbles in the material
which must be evolved out over time before use.  This article offers
a unique solution to point of use filtration for polyamic
acid/polyimide solutions.

      The relationship between...