METHOD OF FABRICATION OF Al/GE BONDING IN A WAFER PACKAGING ENVIRONMENT AND A PRODUCT PRODUCED THEREFROM

Abstract

A method of bonding of germanium to aluminum between two substrates to create a robust electrical and mechanical contact is disclosed. An aluminum-germanium bond has the following unique combination of attributes: (1) it can form a hermetic seal; (2) it can be used to create an electrically conductive path between two substrates; (3) it can be patterned so that this conduction path is localized; (4) the bond can be made with the aluminum that is available as standard foundry CMOS process. This has the significant advantage of allowing for wafer-level bonding or packaging without the addition of any additional process layers to the CMOS wafer.

What is claimed is: 
     
         1 . A microelectromechanical systems (MEMS) device comprising:
 a first substrate comprising a MEMS structure and a patterned germanium layer; and   a second substrate comprising a patterned aluminum layer, wherein germanium of the patterned germanium layer of the first substrate is bonded to aluminum of the patterned aluminum layer of the second substrate.   
     
     
         2 . The MEMS device of  claim 1 , wherein the patterned aluminum layer is patterned to substantially match the patterned germanium layer. 
     
     
         3 . The MEMS device of  claim 1 , wherein the germanium bonded to the aluminum comprises at least one of a hermetic seal, an electrical contact, an insulating contact, or a mechanical contact between the first substrate and the second substrate. 
     
     
         4 . The MEMS device of  claim 3 , wherein the germanium is disposed, at least in part, on a non-conductive layer to create the insulating contact. 
     
     
         5 . The MEMS device of  claim 1 , wherein the first substrate comprises at least one via configured to provide electric feedthrough of signals to the second substrate. 
     
     
         6 . The MEMS device of  claim 1 , wherein the MEMS structure comprises at least one of a MEMS radio frequency (RF) device structure, a MEMS gyroscope sensor structure, a MEMS pressure sensor structure, or an accelerometer sensor structure. 
     
     
         7 . The MEMS device of  claim 1 , wherein at least one of the first substrate or the second substrate comprises at least one of a silicon substrate, a multiple layer of silicon substrates, or a substrate comprising at least one of gallium arsenide (GaAs), indium phosphide (InPh), silicon germanium (SiGe), or glass. 
     
     
         8 . A microelectromechanical systems (MEMS) device comprising:
 a first substrate comprising a patterned germanium layer; and   a second substrate comprising a patterned aluminum layer, wherein germanium of the patterned germanium layer of the first substrate is bonded to aluminum of the patterned aluminum layer of the second substrate.   
     
     
         9 . The MEMS device of  claim 8 , wherein the patterned germanium layer is patterned to substantially match the patterned aluminum layer. 
     
     
         10 . The MEMS device of  claim 8 , wherein the germanium bonded to the aluminum comprises at least one of a hermetic seal, an electrical contact, an insulating contact, or a mechanical contact between the first substrate and the second substrate. 
     
     
         11 . The MEMS device of  claim 8 , wherein the MEMS device comprises at least one of a MEMS radio frequency (RF) device structure, a MEMS gyroscope sensor structure, a MEMS pressure sensor structure, or an accelerometer sensor structure. 
     
     
         12 . The MEMS device of  claim 8 , wherein at least one of the first substrate or the second substrate comprises at least one of a silicon substrate, a multiple layer of silicon substrates, or a substrate comprising at least one of gallium arsenide (GaAs), indium phosphide (InPh), silicon germanium (SiGe), or glass. 
     
     
         13 . A microelectromechanical systems (MEMS) device comprising:
 a first substrate comprising at least one of a patterned germanium layer configured to susbstantially match an aluminum layer of another substrate or the aluminum layer; and   a second substrate comprising the other of the at least one of the patterned germanium layer or the aluminum layer, wherein germanium of the patterned germanium layer is bonded to aluminum of the aluminum layer.   
     
     
         14 . The MEMS device of  claim 13 , wherein the MEMS device comprises at least one of a MEMS radio frequency (RF) device structure, a MEMS gyroscope sensor structure, a MEMS pressure sensor structure, or an accelerometer sensor structure. 
     
     
         15 . The MEMS device of  claim 13 , wherein at least one of the first substrate or the second substrate comprises at least one of a silicon substrate, a multiple layer of silicon substrates, or a substrate comprising at least one of gallium arsenide (GaAs), indium phosphide (InPh), silicon germanium (SiGe), or glass. 
     
     
         16 . The MEMS device of  claim 15 , wherein the at least one the first substrate or the second substrate comprises MEMS structures and a cavity. 
     
     
         17 . The MEMS device of  claim 15 , wherein the at least one of the first substrate or the second substrate comprises a cover substrate. 
     
     
         18 . The MEMS device of  claim 15 , wherein the at least one of the first substrate or the second substrate comprises an integrated circuit. 
     
     
         19 . The MEMS device of  claim 13 , wherein the germanium bonded to the aluminum comprises at least one of a hermetic seal, an electrical contact, an insulating contact, or a mechanical contact between the first substrate and the second substrate. 
     
     
         20 . The MEMS device of  claim 13 , wherein the patterned germanium layer is patterned to substantially match a patterned portion of the aluminum layer.