Low-Temperature Sintering of Nanoscale Silver Paste for Semiconductor Device Interconnection

This research has developed a lead-free semiconductor device interconnect technology by studying the processing-microstructure-property relationships of low-temperature sintering of nanoscale silver pastes. The nanoscale silver pastes have been formulated by adding organic components (dispersant, binder and thinner) into nano-silver particles. The selected organic components have the nano-particle polymeric stabilization, paste processing quality adjustment, and non-densifying diffusion retarding functions and thus help the pastes sinter to ~80% bulk density at temperatures no more than 300°C. It has been found that the low-temperature sintered silver has better electrical, thermal and overall thermomechanical properties compared with the existing semiconductor device interconnecting materials such as solder alloys and conductive epoxies. After solving the organic burnout problems associated with the covered sintering, a lead-free semiconductor device interconnect technology has been designed to be compatible with the existing surface-mounting techniques with potentially low-cost. It has been found that the low-temperature sintered silver joints have high electrical, thermal, and mechanical performance. The reliability of the silver joints has also been studied by the 50-250°C thermal cycling experiment. Finally, the bonging strength drop of the silver joints has been suggested to be ductile fracture in the silver joints as micro-voids nucleated at microscale grain boundaries during the temperature cycling. The low-temperature silver sintering technology has enabled some benchmark packaging concepts and substantial advantages in future applications.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Materials Science and Engineering

Department dc:contributor.department

Materials Science and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2005

Author dc:creator

• Bai, Guofeng

Chair dc:contributor.committeechair

• Lu, Guo-Quan

Committee members dc:contributor.committeemember

• Corcoran, Sean G.
• van Wyk, Jacobus Daniel
• Reynolds, William T. Jr.
• Boroyevich, Dushan

• Silver joint
• Reliability
• Lead-free solution
• Semiconductor device interconnection
• Low-temperature sintering
• Electronic packaging
• Nanoscale silver paste

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-10312005-163634

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/29409