Reduction of thermal expansion coefficient of electrodeposited copper

1. With the additive A, this copper shrinks with raising the temperature for the first time anneal. Most materials expands with raising the temperature, and this copper shrinks. For the second time anneal, this copper shows about half of the TEC of conventional copper at 400°C. 2. TSV of 4μm in width and 25μm depth has no voids or seams and a perfect filling has been achieved. 3. Addition of the additive A miniaturize the grain size after annealing at 400°C. The impurities from the additive A is considered to segregate at the grain boundaries and inhibit the grain growth at the annealing. 4. In-situ SEM observation of pumping with annealing will be presented at the meeting.