A Low-Temperature Batch Mode Packaging Process for Submillimeter Microsystems in Harsh Environment Applications

This paper presents a low-temperature batch mode packaging process for microsystems that are intended for harsh environments, in particular those with high pressure and high salinity, such as encountered in downhole data logging for oil exploration and production. The package consists of a shell made from a high-strength material, such as stainless steel (SS), and an insert made from a deformable material, such as aluminum (Al). The process includes a batch mode method for chip integration and a batch mode microcrimping method for package assembly. In a process demonstration, a
$5 \times 5$
array of packages was made from SS 316 and Al alloy 3003, with dummy silicon chips encapsulated inside. Each package had an outer dimension of 0.5 mm along each axis. Two layers of coatings were deposited on the packages, including 50-nm-thick Al
₂
O
₃
deposited by atomic layer deposition and 5-
$\mu \text{m}$
-thick Parylene C made by vapor phase deposition to protect against corrosion. The packages survive at least 72 h in the standard American Petroleum Institute hot brine at 80 °C. The packages also survive pressure >200 MPa.