Patent ID: 8956904
Filing Date: 2015-02-17
Classification: B81C,H01L

Abstract:
1. A method of forming a MEMS device, the method comprising, providing a first wafer; providing a second wafer, at least one of the first and second wafers having a two-dimensional array of MEMS devices; depositing a layer of first germanium onto the first wafer; depositing a layer of aluminum onto the second wafer; depositing a layer of second germanium onto the second wafer, the layer of second germanium being deposited on the layer of aluminum, bringing the first wafer into contact with the second wafer so that the first germanium contacts the second germanium; heating the first and second wafers when the first and second germanium are in contact; and cooling the wafers to form a plurality of conductive hermetic seal rings about the plurality of the MEMS devices, such that at least one of the seal rings has varying concentrations of aluminum, germanium, or aluminum/germanium eutectic, the region of the seal ring adjacent to the second wafer having a higher concentration of aluminum than the region of the seal ring adjacent to the first wafer, and the region of the seal ring adjacent to the first wafer having a higher concentration of germanium than the region of the seal ring adjacent to the second wafer, the seal rings bonding the first wafer to the second wafer.