A Comparison of Environmental Stressing Data and Simulation at the Corner of a Test Chip in a FC-BGA Package
- Resource Type
- Conference
- Authors
- Mallampati, Sandeep; Baig, Zaeem; Pozder, Scott; Chua, Eng Chye
- Source
- 2019 IEEE International Reliability Physics Symposium (IRPS) Reliability Physics Symposium (IRPS), 2019 IEEE International. :1-4 Mar, 2019
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Engineering Profession
Substrates
Stress
Reliability
Finite element analysis
Flip-chip devices
Temperature measurement
Laminates
CTE mismatch
core thickness
underfill
nanoindentation
finite element model
Flip Chip- BGA
- Language
- ISSN
- 1938-1891
Thermal expansion mismatches pose significant challenges to the reliability of flip chip-Ball grid array (FC-BGA) package technology. Technology advancement for FC-BGA packages drives towards thinner substrates, smaller bump pitch and high flow underfills. In this work, the risk of corner cracking is studied using two substrate thickness and underfill types. Environmental stressing is performed beyond the JEDEC recommended limits in order to drive the units to failure. It is observed substrates with a thinner core and underfill with higher CTE produced 5⨯ to 10⨯ more number of cracks in the underfill compared to other cases. Finite element modeling is used to compare the corner stresses to the observed cracking as a means to identify conditions with higher cracking risk. In order to understand if a potential material root-cause of cracking exists, nanoindentation is used to measure the hardness and elastic modulus of underfills before and after stressing.