Rapid realization of ultra-high vacuum packaging of atomic chips by thick film technology

This research is an attempt to apply the silver thick-film metallization and the soft soldering process to the ultra-high vacuum packaging of atom chips with through silicon via (TSV). During the packaging process, a vacuum environment is used to avoid oxidation of the Cu layer on the chip during heating. At the same time, tin foil is used to protect the inner wall of the glass cell to prevent the gas emitted by the solder from polluting the inner wall. In general, by the adoption of screen printing, sintered surface metallization at a constant temperature of 450-500 degrees C for 5 min, combined with soft soldering, the packaging of an atom chip with TSV and a silica glass cell is realized. The weld gap is less than 50 mu m, the airtightness can reach 8.5 x 10-13 Pa m3/s, and the vacuum degree can reach 2.18 x 10-8 Pa. That can meet the requirements of cold atom experiment for light path and vacuum degree.

Automated summary

This research applies silver thick-film metallization and soft soldering to achieve ultra-high vacuum packaging of atom chips with through silicon via (TSV). The packaging process is conducted in a vacuum environment to prevent oxidation of the copper layer on the chip. Tin foil is used to protect the inner wall of the glass cell from solder emissions. By using screen printing, sintered surface metallization, and soft soldering, the packaging of atom chips with TSV and a silica glass cell is successfully achieved, meeting the requirements of cold atom experiments.