By Topic

Study on the Effect of Wafer Back Grinding Process on Nanomechanical Behavior of Multilayered Low-k Stack

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

9 Author(s)
Vasarla Nagendra Sekhar ; Institute of Microelectronics, Agency for Science, Technology and Research, 117685, Singapore ; Lu Shen ; Aditya Kumar ; Tai Chong Chai
more authors

This paper presents the effect of back grinding on the mechanical properties of the active side of the multilayered low-k stacked die. Low-k stacked wafers were thinned to four different thicknesses of 500, 300, 150, and 75 μm by using a commercial grinding process. Nanoindentation and nanoscratch tests were performed on both the normal (no back grinding) and back grinded samples to analyze the failure strength, modulus, hardness and adhesive/cohesive strength of the low-k stack. It is found that the back grinding process enhances the mechanical integrity of low-k stack as the back grinded low-k stack exhibited improved fracture load and cohesive and/or adhesive strength as compared to the normal low-k stack. The transmission electron microscopy cross-section analysis showed that the interfaces in the low-k stack of normal sample are wavy, whereas the interfaces in the grinded low-k stack samples are even, especially at the Black Diamond (BD), low-k region. Significant densification of BD films was observed in the case of back grinded sample. Based on these results, it is believed that the thermo-mechanical stresses applied and/or generated during wafer back grinding process affect the microstructure of low-k stack and thus enhance the mechanical strength of the low-k stack.

Published in:

IEEE Transactions on Components, Packaging and Manufacturing Technology  (Volume:2 ,  Issue: 1 )