Fabrication and Traceable Quality Evaluation of Fine Pitch TSV with Self-Integrated Micro Heater and Thermocouple

As the pitch of TSVs shrinks down, electrical characteristics of TSV become more complicated and mechanical stress becomes a critical issue. The objective of this paper is to study the electrical and mechanical characteristics of fine pitch TSV. The features are that the fine pitch TSV samples are fabricated with self-integrated micro heater and thermocouple, which are integrated to act as the hot spot and to online monitor the temperature variation during test respectively. X-ray inspection is carried out to verify the internal filling quality of fine pitch TSV electroplating. The appearance of micro heater and thermocouple are observed by 3D profiler. The cross section of this fine pitch TSV is observed by scanning electron microscope. The yield of all test structure turns out to be 99.50% at the laboratory level. The values of Kelvin resistance in test structure is measured by changing the temperature of self-integrated micro heater. Thermo-mechanical stress is qualitative characterized by an infrared photo-elastic system during thermal shock which demonstrates that around of the failure TSV is under more stress, through which we can evaluate the quality of fine pitch TSV fast and accurately.