Georgia Tech Research Corporation

Ankur Aggarwal

Rao R Tummala

Pulugurtha Markondeya Raj

Isaac Robin Abothu

A low-temperature process that combines high-aspect-ratio polymer structures with electroless copper plating to create laterally compliant MEMS structures. These structures can be used as IC-package interconnects that can lead to reliable, low-cost and high-performance nano wafer-level packaging. High-aspect-ratio low CTE polyimide structures with low stress, high toughness and strength were fabricated using plasma etching. The dry etching process was tuned to yield a wall angle above 80 degrees leading to an aspect ratio higher than 4. The etching process also leads to roughened sidewalls for selective electroless plating on the sidewalls of the polymer structures. These fabricated structures show reduction in the stresses at the interfaces and superior reliability as IC-package nano interconnects. Metal-coated polymer structures from MEMS fabrication techniques can provide low-cost high-performance solutions for wafer-level-packaging. Other embodiments are also claimed and described.

High-aspect-ratio metal-polymer composite structures for nano interconnects

Nano-structured interconnect formation and a reworkable bonding process using solder films. Large area fabrication of nano-structured interconnects is demonstrated at a very fine pitch. This technology can be used for pushing the limits of current flip chip bonding in terms of pitch, number of I/Os, superior combination of electrical and mechanical properties as well as reworkability. Sol-gel and electroless processes were developed to demonstrate film bonding interfaces between metallic pads and nano interconnects. Solution-derived nano-solder technology is an attractive low-cost method for several applications such as MEMS hermetic packaging, compliant interconnect bonding and bump-less nano-interconnects.

Lead-free bonding systems

A low-temperature process that combines high-aspect-ratio polymer structures with electroless copper plating to create laterally compliant MEMS structures. These structures can be used as IC-package interconnects that can lead to reliable, low-cost and high-performance nano wafer-level packaging. High-aspect-ratio low CTE polyimide structures with low stress, high toughness and strength were fabricated using plasma etching. The dry etching process was tuned to yield a wall angle above 80 degrees leading to an aspect ratio higher than 4. The etching process also leads to roughened sidewalls for selective electroless plating on the sidewalls of the polymer structures. These fabricated structures show reduction in the stresses at the interfaces and superior reliability as IC-package nano interconnects. Metal-coated polymer structures from MEMS fabrication techniques can provide low-cost high-performance solutions for wafer-level-packaging.

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Smyrna, GA, United States of America

Ankur Aggarwal