Browse Prior Art Database

Biphenylene Dianhydride/Para-Phenylene Diamine/Meta-Pheylene Diamine Copolymers: More Isotpropic, Transparent, Flexible Polyimides

IP.com Disclosure Number: IPCOM000113490D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Angelopoulos, M: AUTHOR [+3]

Abstract

Disclosed are novel polyimide copolymers which combine low anisotropy and high transparency with good mechanical and physical properties. These polymers can be used as dielectrics or as photosensitive dielectrics for electronic packaging applications as well as polymer waveguides.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Biphenylene Dianhydride/Para-Phenylene Diamine/Meta-Pheylene Diamine
Copolymers: More Isotpropic, Transparent, Flexible Polyimides

      Disclosed are novel polyimide copolymers which combine low
anisotropy and high transparency with good mechanical and physical
properties.  These polymers can be used as dielectrics or as
photosensitive dielectrics for electronic packaging applications as
well as polymer waveguides.

      Polyimides are extensively used in the microelectronics
industry in applications such as passivation layers on integrated
circuits, interlevel dielectrics for multilevel interconnections, and
as alignment layers for liquid crystal displays.  Of particular
importance has been the polyimide based on biphenylene dianhydride
(BPDA) and para-phenylene diamine (p-PDA) because it exhibits
excellent thermal and mechanical properties, a low coefficient of
thermal expansion (CTE), low stress, and a low dielectric constant
(3.0) measured along the film thickness.  However, BPDA/p-PDA also
has some undesirable properties which may limit its full scope of
applications.  First, it has been reported that this polyimide
displays very high anisotropy in the optical refractive indices.  The
in-plane value is 1.852 and the out-of-plane value is 1.612 at 632.8
nm wavelength as measured by prism coupling (*).  This observed high
anisotropy suggests a large anisotropy in dielectric constant as well
and thus, the in-plane dielectric constant is expected to be much
higher than 3.0.  The in-plane dielectric constant is an important
consideration in the design of devices.  Second, BPDA/p-PDA exhibits
high absorption in most of the ultraviolet region.  This high
absorption would limit the efficiency of a photosensitive polyimide
(PSPI) based on this polymer backbone as there would be competitive
absorption between the polymer and any initiators required for
photochemistry.  In addition, BPDA/p-PDA is a highly rigid polymer
and as a consequence does not exh...