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Deformation Behavior of Various Interconnection Structures Using Fine Pitch Microelectromechanical Systems (MEMS)
Xuan Luc Le1, Han Eul Lee2, Sung-Hoon Choa1
1Graduate School of Nano IT Design Fusion, Seoul National University of Science and Technology, Seoul, 01811, Republic of Korea.
Journal of Nanoscience and Nanotechnology
|March 3, 2021
Summary
Wafer level packaging (WLP) interconnection structures deform significantly during probing, with solder and copper pillar bumps showing the most deformation. Minimizing probe overdrive is key to preventing damage during wafer testing.
Area of Science:
- Materials Science
- Semiconductor Manufacturing
- Mechanical Engineering
Background:
- Fine pitch wafer level packaging (WLP) is crucial in the semiconductor industry.
- Wafer level testing demands understanding probe-to-interconnection contact behavior for reliability.
- Interconnection structures like microbumps and through-silicon-vias (TSVs) are key components.
Purpose of the Study:
- To numerically analyze the deformation of various interconnection structures under probing.
- To evaluate the impact of probe contact on solder bumps, copper pillar bumps, solder-capped copper bumps, and TSVs.
- To provide guidelines for minimizing damage during wafer-level testing.
Main Methods:
- Systematic numerical analysis using a MEMS vertical probe.
- Simulation of probe contact and deformation on different interconnection structures.
- Analysis of deformation, stress, and material behavior.
Main Results:
- Solder balls and copper pillar bumps exhibited the largest deformation.
- Copper bumps deformed at 10 μm overdrive, with height reduction at 20 μm.
- Solder-capped copper bumps showed significant deformation, reducing total height by 11% at 20 μm overdrive.
- Through-silicon-vias (TSVs) deformed minimally but induced high stress and shear stress, with copper protrusion observed.
Conclusions:
- Interconnection structure deformation is a critical issue in wafer-level testing.
- TSVs present unique challenges due to high stress and potential for copper protrusion.
- Optimizing probe size and reducing overdrive are essential to minimize damage to probes and interconnections.
