Direct Al-Al contact in silicon-Pyrex7740 anodic bonding for hermetic package and electrical interconnecting

A hermetic package by silicon-Pyrex7740 anodic bonded structure which has Al electronic contact pads in the bonding area has been successfully demonstrated. Silicon wafer was doped with boron at the dose about 2×10²⁰cm^-3, then Al contact pads were deposited by using RF sputtering on silicon and Pyrex7740 respectively. Sufficient mechanical strength has been test after silicon-Pyrex7740 anodic bonding, though with Al contact pads on the bonding surface. IPA (Isopropanol Alcohol) test and accelerate test in an autoclave are used to detect the hermitic package quality. The results show that the anodic bonding with Al pads sandwiched in the banded structure has no influence on hermetic packaging. The average sheet resistance of the Al contact pads is 3.45ohmic/□ which calculated form I-V tested, indicating that direct Al-Al interconnecting is suitable for electrical interconnecting for integration of MEMS devices.