Investigations of the influence of dicing techniques on the strength properties of thin silicon

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Stephan Schoenfelder - , Fraunhofer Institute for Mechanics of Materials (Author)
  • Matthias Ebert - , Fraunhofer Institute for Mechanics of Materials (Author)
  • Christof Landesberger - , Fraunhofer Institute for Reliability and Microintegration (Author)
  • Karlheinz Bock - , Fraunhofer Institute for Reliability and Microintegration (Author)
  • Jörg Bagdahn - , Fraunhofer Institute for Mechanics of Materials (Author)

Abstract

Thin silicon offers a variety of new possibilities in microelectronical, solar and micromechanical industries, e.g. for 3D-integration (stacked dies), thin microelectromechanical packages or thin single crystalline solar cells. The wafers in this investigation were thinned back by grinding and subsequent spin etching steps for stress relief followed by separation into single test dies by sawing or etching. In order to characterize and optimize relevant process steps in terms of quality and fabrication yield, the mechanical properties were investigated considering the defect formation and strength. In this paper the influence of three different dicing technologies on the mechanical strength of thin silicon samples was investigated by 3-point bending tests. Sawing, Dicing-by-Thinning with sawn grooves and Dicing-by-Thinning with dry-etched trenches were used as dicing technologies. Analytical and numerical calculations were performed to calculate fracture stresses from fracture forces in 3-point bending tests taking into account the non-linear relationship of force and displacement during testing. Thus the fracture stress as a parameter of strength could be calculated for all tested samples. The results were statistically evaluated by the Weibull distribution based on the weakest link theory. This approach allows a more comprehensive understanding of the influence of the process on strength properties independently of geometric factors. Samples, being separated by "Dicing-by-Thinning", have much higher strength than simply sawed samples. If trenches are fabricated by dry-etched process the strength can be increased tremendously.

Details

Original languageEnglish
Pages (from-to)168-178
Number of pages11
JournalMicroelectronics Reliability
Volume47
Issue number2-3
Publication statusPublished - Feb 2007
Peer-reviewedYes
Externally publishedYes

External IDs

ORCID /0000-0002-0757-3325/work/139064968