Metal fusion bonding – Process – Diffusion type
Reexamination Certificate
2001-01-16
2001-12-25
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Diffusion type
C228S180100, C228S194000, C228S205000
Reexamination Certificate
active
06332568
ABSTRACT:
BACKGROUND
This invention relates to methods of forming micromachines and components. More particularly, it relates to a fabrication process wherein micromachine subassemblies on separate substrates are diffusion bonded together to form a united structure.
Micromachines are potentially useful for a wide range of applications requiring robust and complex miniature mechanisms, and particularly for forming an interface between complex microelectronic circuitry and the external world. Many such applications, however, require many discrete levels of components, some of which components are thick compared to the average component thickness, to provide the required functionality. Multiple component levels and thick components, however, are difficult to fabricate based solely on the planar microfabrication techniques known in silicon microelectronics and in such metallic-based fabrication techniques as LIGA (LIGA is a German acronym which stands for lithography, electroplating, and molding). Even when high-aspect-ratio fabrication techniques are used, maintenance of precise intercomponent separations and tolerances is often difficult. In addition, even though suitable techniques exist to planarize the surface of a micromachine subassembly, so that further growth and component definition can take place, problems and costs associated with such serial microfabrication dramatically limit the use of these techniques.
There is therefore a need for a method to enable assembly of micromachine subassemblies which require multi-level precision structures. A further need is for a method which can be used to assemble such micromachines in batches, preferably on the scale of entire substrate wafers. Application of such techniques to packaging of micromachines will also be useful to the industry.
SUMMARY OF THE INVENTION
A method for assembling a pair of micromachine subassemblies, each initially fabricated on its own substrate, and each having a planar upper mating surface. At least one of the substrates also has a release layer located between the substrate proper and the micromachine subassembly. The substrates are oriented so that their upper mating surfaces face each other, and then are pressed together in proper relative orientation. The conditions of temperature, pressure, and time under which the pressing is done are such as to result in diffusion bonding of the upper mating surfaces. After this diffusion bonding step, the release layer is removed, thereby yielding a micromachine assembly atop one of the substrates.
REFERENCES:
patent: 3657801 (1972-04-01), Hershenson
patent: 4624404 (1986-11-01), Ohmae et al.
patent: 4763828 (1988-08-01), Fukaya et al.
patent: 5440805 (1995-08-01), Daigle et al.
patent: 5442144 (1995-08-01), Chen et al.
patent: 5763941 (1998-06-01), Fjelstad
patent: 5988488 (1999-11-01), Slattery et al.
patent: 6192596 (2001-02-01), Bennett et al.
patent: 6272159 (2001-08-01), Garcia
WO 94/17551 Williams et al. (Aug. 4, 1994).*
US 2001-0001989 A1 Smith (May 31, 2001).
Dodson Brian W.
Dunn Tom
Sandia Corporation
Stoner Kiley
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