Fig. 1. Overview of PEB face-down interconnection process.
Fig. 2. Von-Mises stress analysis of single bump package at 3-μm displacement at 25℃.
Fig. 3. Von-Mises stress analysis of single bump package at 3-μm displacement at 225℃.
Fig. 4. Deformation behavior analysis of polymer elastic bump w.r.t. bonding force and temperature.
Fig. 5. Elastic polymer bump design with various type of bump metal pattern.
Fig. 6. Elastic deformation shape of various type of PEB w.r.t. temperature.
Fig. 6. Continued.
Fig. 7. Von-Mises stress of various bump metal patterns w.r.t. temperature.
Fig. 7. Continued.
Fig. 8. Calculated Polymer elastic bump contact area variation w.r.t. bump metal pattern and bonding force per bump.
Fig. 9. Fabrication process of polymer elastic bump chip.
Fig. 10. Shapes of polymer bumps after thermal reflow process depending on film thickness.
Fig. 11. Polymer elastic bump shape before and after thermal reflow depending on photoresist volume.
Fig. 12. Polymer bump diameter and height measured after thermal reflow process at photoresist thickness of 28 μm.
Fig. 13. Fabricated Polymer elastic bump(PEB) shape by thermal reflow process.
Fig. 14. Experimental set-up for investigation of polymer elastic bump deformation behavior using micro-tribometer.
Fig. 15. CCD Images of contact area variation of polymer elastic bump due to bump deformation w.r.t. bump load at 25℃.
Fig. 16. Results of deformation behavior of circle bump cap with a microtribometer test according to temperature and load.
Fig. 17. Metal pattern crack images and 3D shape profile of polymer elastic bumps w.r.t temperature.
Fig. 17. Continued.
Fig. 18. Method for measuring contact resistance and measured contact resistance depending on bump cap shape.
Fig. 19. Cross-section images of bonded glass chip and FPCB with polymer elastic bump.
Table 1. Contact diameter depending on temperature and load [μm]
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