RECENT HUMIDITY ACCELERATIONS, A BASE FOR TESTING STANDARDS

SUMMARY Accelerated humidity test data on plastic res are analysed, showing higher thermal acceleration and longer life for modem components compared to older ones. Accelerations for total test time in humidity are given, and the effect of assumed moisture ingress time through the plastic is also treated. A procedure for formal qualification of moisture life is proposed. obtain the estimate of 1m after the removal of freak failures'" from the distribution. The observed ratio, R o , of 1m (T/RH) to 1m (85/85) was then comparcd with the calculated ratio, Re , according to the for­ mula being investigated. The ratios were examined to obtain thc smallest standard deviations and the highest correlation coefficient between R o and Re . Since the same electrical bias conditions were held through each study, the ratios normalize the effects of test-ta-test variations in bias, device structure or contamination level. A common relationship was found to be optimum for stresses both higher and lower than the reference (85/85) from 158°C down to 50°C and from 100 per cent RH down to 50 per cent RH, the range of the available data. The formula has the form

[1]  D. S. Peck,et al.  Temperature-Humidity Acceleration of Metal-Electrolysis Failure in Semiconductor Devices , 1973 .

[2]  T. Steiner,et al.  Investigations of Large PLCC Package Cracking During Surface Mount Exposure , 1987 .

[3]  M. C. Halleck.  The I.C. Plastic Package a Simple Method for Predicting Package Performance , 1972 .

[4]  Robert E. Camenga,et al.  Rapid Assessment of the Humidity Dependence of IC Failure Modes by Use of HAST , 1983, 21st International Reliability Physics Symposium.

[5]  H. Higuchi,et al.  A New Cyclic Biased T.H.B. Test for Power Dissipating IC's , 1979, 17th International Reliability Physics Symposium.

[6]  J. Suzuki,et al.  Automatically Controlled 2-Vessel Pressure-Cooker Test-Equipment , 1983, IEEE Transactions on Reliability.

[7]  J. E. Gunn,et al.  Highly Accelerated Temperature and Humidity Stress Test Technique (HAST) , 1981, 19th International Reliability Physics Symposium.

[8]  Kunihiko Nishi,et al.  Analysis of package cracking during reflow soldering process , 1988, 26th Annual Proceedings Reliability Physics Symposium 1988.

[9]  J. L. Flood.  Reliability Aspects of Plastic Encapsulated Integrated Circuits , 1972 .

[10]  Christer Olsson.  Reliability of plastic-encapsulated logic circuits , 1989 .

[11]  Dale W. Dycus.  Moisture Uptake and Release by Plastic Molding Compoundsits Relationship to System Life and Failure Mode , 1980, 18th International Reliability Physics Symposium.

[12]  R P Merrett,et al.  An Appraisal of High Temperature Humidity Stress Tests for Assessing Plastic Encapsulated Semiconductor Components , 1983, 21st International Reliability Physics Symposium.

[13]  T. Wada,et al.  A Paradoxical Relationship between Width/Spacing of Aluminum Electrodes and Aluminum Corrosion , 1985, 23rd International Reliability Physics Symposium.

[14]  D. Stewart Peck,et al.  Comprehensive Model for Humidity Testing Correlation , 1986, 24th International Reliability Physics Symposium.

[15]  D. Peck,et al.  The Design and Evaluation of Reliable Plastic-Encapsulated Semiconductor Devices , 1970 .

[16]  S P Sim,et al.  The Influence of Plastic Encapsulants and Passivation Layers on the Corrosion of Thin Aluminium Films Subjected to Humidity Stress , 1979, 17th International Reliability Physics Symposium.

[17]  H. Koelmans,et al.  Metallization Corrosion in Silicon Devices by Moisture-Induced Electrolysis , 1974 .

[18]  R. Lawson.  A review of the status of plastic encapsulated semiconductor component reliability , 1984 .