The Effects of Substrate Composition on Thick Film Circuit Reliability.
Abstract
Studies of the rate of dissolution of 96% Al2O3 substrates (AlSiMag 614) in a model glass (63 w/o Pb0-20 w/o B203-10 w/o SiO2) were conducted as a function of temperature from 750 to 950 C. The rate limiting step was found to be molecular diffusion of substrate ingredients in the glass at times pertinent to thick film processing. Data from experiments on substrate dissolusion in glasses having varying amounts of substrate previously dissolved were utilized to develop an analytical expression which will give the substrate recession as a function of time and temperature for an actual thick film resistor; predictions of this equation compared favorably with experimental data. Studies of the influence of substrate constituents dissolved in the glass on the electrical properties of resistors showed a significant effect on both sheet resistance and temperature coefficient of resistance (TCR). The sheet resistance increased and the TCR decreased as the amount of substrate dissolved in the glass increased for the same processing conditions. These results are consistent with the present model of charge transport processes in thick film resistors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 28, 1978
- Accession Number
- ADA054316
Entities
People
- R. W. Vest
Organizations
- Purdue University