The Effects of Substrate Composition on Thick Film Circuit Reliability.
Abstract
During this quarter studies of the rate of the dissolution of 99.5% Al203 substrates (AlSiMag 772) in the model glass (63% PbO, 25% B2O3, 12% SiO2) were conducted as a function of time at 800 C. The results were similar to those reported earlier for 96% Al2O3 substrates (AlSiMag 614) and were consistent with the proposed rate limiting steps of phase boundary reaction rate control at short times and diffusion through a boundary layer under natural convection at longer times. The dissolution rate of AlSiMag 614 substrates was measured at short contact times (3-15 minutes) by atomic absorption techniques and were in good agreement with values predicted by extrapolation of longer time data at 800 C. Studies of the distribution of substrate ingredients throughout the resistor glass at 800C as a function of time showed that the boundary zone at the interface across which the concentrations change has a width of approximately 3 micrometers and is independent of contact time. Studies of the influence of substrate constituents dissolved in the glass on electrical properties of resistors uncovered a significant effect on temperature coefficient of resistance (TCR). A low TCR characteristics of reliable thick film resistors cannot be achieved with the model system unless an appreciable amount of substrate material is dissolved in the resistor glass. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1976
- Accession Number
- ADA033963
Entities
People
- R. W. Vest
Organizations
- Purdue University