Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Effect of Coating Thickness and Curing Temperature on Residual Stress and Thermal Expansion Coefficients of High Glass Transition Temperature Polymides

IP.com Disclosure Number: IPCOM000105983D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Hofer, DC: AUTHOR [+3]

Abstract

A number of high glass transition temperature (T sub g s) polyimides are in use as insulators for multilevel wiring in semiconductor chip and thin film packaging applications throughout the computer industry. Each of the polyimides is thought to have a distinctive set of Young's modulus, Poisson's ratio and thermal expansion coefficient that determines the stress in a coating of the material on a substrate and that these three physical properties are characteristics of the material. Therefore, the stress in a coating should be independent of thickness. In general, it has been observed that this classic understanding is not accurate for a class of polymides which have (T sub g s) of approximately 400ºC and are processed to temperatures greater than the (T sub g)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 83% of the total text.

Effect of Coating Thickness and Curing Temperature on Residual Stress and Thermal Expansion Coefficients of High Glass Transition Temperature Polymides

      A number of high glass transition temperature (T sub g s)
polyimides are in use as insulators for multilevel wiring in
semiconductor chip and thin film packaging applications throughout
the computer industry.  Each of the polyimides is thought to have a
distinctive set of Young's modulus, Poisson's ratio and thermal
expansion coefficient that determines the stress in a coating of the
material on a substrate and that these three physical properties are
characteristics of the material.  Therefore, the stress in a coating
should be independent of thickness.  In general, it has been observed
that this classic understanding is not accurate for a class of
polymides which have (T sub g s) of approximately 400ºC and
are processed to temperatures greater than the (T sub g)

      As an example of the phenomena described above it was found
that the polyimide BPDA-PDA coated to thickness of 1.3,  7.5  and
38.7  microns on a Si substrate produced stresses of 0.8, 2.9, 4.7
and 6.2 kpsi, respectively.  Furthermore, when multiple coatings (3
to 5 coats) of the same polyimide were made with a thickness of 1.3
microns/coat the stress was largely independent of thickness when the
film was cured between each of the multiple coatings.  This phenomena
nomena exists with varying degree for the polyimides PMDA-ODA,
PMDA-PDA,...