Microstructures

• US 6,436,853 B2
• Filed: 02/27/2001
• Issued: 08/20/2002
• Est. Priority Date: 12/03/1998
• Status: Expired due to Fees

• Current Assignee: University of Michigan
• Original Assignee: University of Michigan
• Inventors: Cheng, Yu-Ting, Lin, Liwei, Wise, Kensall D., Najafi, Khalil
• Primary Examiner(s): Christianson, Keith
• Assistant Examiner(s): Huynh, Yennhu B
• Application Number:
  US09/794,455
• Publication Number:
  US 20010021570A1
• Time in Patent Office: 539 Days
• Field of Search: 438/800, 438/119, 438/54, 438/55, 438/456, 438/64, 438/67, 438/455-457, 257/682, 257/698, 257/731, 257/760, 257/678, 257/798
• US Class Current: 438/800
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 2203/0181 Using microheaters for bonding the lid
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: H01L 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip
• CPC Class Codes: H03H 3/0072 of microelectro-mechanical resonators or networks micromembranes or microbeams B81B2203/01; manufacture of microstructural devices in general B81C
• CPC Class Codes: H03H 9/1057 for microelectro-mechanical devices

Abstract

A method for making a microstructure assembly, the method including the steps of providing a first substrate and a second substrate; depositing an electrically conductive material on the second substrate; contacting the second substrate carrying the electrically conductive material with the first substrate; and then supplying current to the electrically conductive material to locally elevate the temperature of said electrically conductive material and cause formation of a bond between the first substrate and the second substrate.

Claims

1. A microstructure for simultaneously micropackaging a plurality of microelectronic devices, the microstructure comprising:

a first substrate wafer;

a first array of microdevices mounted on the first substrate wafer;

a second substrate wafer;

a corresponding second array of micropackages defining a predetermined volume and an open aperture along at least one side, the micropackages mounted on the second substrate wafer, the micropackages being aligned such that the second array matches the first array;

a corresponding array of microheaters, each said microheater mounted on a respective one of the micropackages of the second array along a predetermined peripheral boundary line area;

electrically conductive interconnection lines electrically interconnected between the microheaters of the second array on the second substrate, wherein the second substrate is connectible with the first substrate such that each microdevice in the first array is covered by one of the micropackages in the second array, and such that the corresponding array of microheaters is interposed between the first array of devices and the second array of micropackages; and

a localized high-temperature bond interposed between the first substrate and the second substrate to enclose the predetermined volume therebetween.

2. A microstructure having two bodies bonded together at respective surfaces of said bodies comprising:

a first body having a first surface made of a first material;

a second body having a second surface made of a second material and having an opening defining a cavity of a predetermined volume;

a resistive heating material extending along a predetermined peripheral boundary line path of the opening carried on said second surface, and defining a localized high-temperature bonding area between said first and second surfaces where said path is electrically conductive;

a localized high-temperature bonding interface joining said first and second bodies together between said first and second surfaces and bonded together by localized heat from current supplied to said resistive heating material.

3. The microstructure of claim 2 further comprising, said bonding interface forming a seal cooperating with said first and second bodies to sealingly enclose said cavity.

4. The microstructure of claim 2 wherein said second body is a composite comprising said second material and a third material disposed between said second material and said resistive heating material.

5. The microstructure of claim 4 wherein said third material is electrically insulating.

6. The microstructure of claim 4, wherein said third material is selected from the group consisting of silicon dioxide, silicon nitride, and mixtures thereof.

7. The microstructure of claim 2 wherein said bonding interface includes a bonding material between said resistive heating material and said first surface.

8. The microstructure of claim 2 wherein said resistive heating material constitutes a bonding material of the bonding interface.

9. The microstructure of claim 2 wherein said resistive heating material is selected from the group consisting of gold and polysilicon.

10. The microstructure of claim 2 wherein the second material is selected from the group consisting of silicon, glass, aluminum, platinum, tungsten, any other refractory metal, and mixtures thereof.

11. The microstructure of claim 2 wherein the bonding interface includes a bonding material selected from the group consisting of silicon dioxide, silicon, gold, copper, titanium, polysilicon, glass frit, PSG, BSG, soldering materials such as indium, silicon/gold alloy, and silicon/aluminum alloy, and mixtures thereof.

12. The microstructure of claim 2 wherein said bonding interface includes a bonding material characterized by being the decomposition product of a gaseous precursor which decomposes on contact with said resistive heating material.

13. The microstructure of claim 12 wherein said bonding interface includes a bonding material defined by a decomposition product selected from the group consisting of silicon carbide;

molybdenum, nickel, and tungsten.

14. The microstructure of claim 12 wherein said bonding interface comprises a eutectic bond formed by said first material which is silicon and said bonding material which is gold.

15. The microstructure of claim 2 wherein said bonding interface comprises the following materials fused together:

said first material which is one of silicon and glass, and said bonding material which is silicon.