Reliability of Multilayer Copper/Polyimide
Abstract
The reliability of copper/polyimide (PI) multilayer structures was analyzed and found to depend on processing and environmental conditions. Copper films were deposited by thermal evaporation and patterned by contact lithography. Preimidized P12590-D polyimide films were spin coated over the copper with upper layers deposited as required. While the electrical characteristics of the multilayer structures generally behaved as expected, the softening of the underlying PI films led to observation of film buckling and dielectric breakdown in some samples. Consequently, alternate low temperature plasma and laser techniques for depositing copper on PI films, instead of PI films on copper, were explored to improve the reliability of the resulting Cu/PI multilayer structures. Copper films were deposited on PI substrates by radio frequency (13.56 MHz) plasma-induced reduction and excimer laser-induced ablation of copper formate. While the Cu/PI interface appears clean, the reduction of the formate was not complete with some residual carbon contamination in the copper film. Several methods for improving the purity of the Cu films were investigated. Diamondlike carbon (DLC) films are excellent barriers for the diffusion of Cu in Cu/Si structures. DLC films, due to their excellent compatibility with PI, may play a similar useful role in Cu/PI structures and improve their reliability. Copper/polyimide(PI), Diamondlike carbon(DLC) films, Cu/PI Multilayer structures.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1993
- Accession Number
- ADA276228
Entities
People
- D. H. Rasmussen
- D. W. Lawrence
- S. V. Babu
Organizations
- Clarkson University