Cold weld hermetic MEMS package and method of manufacture

• US 20050263878A1
• Filed: 05/27/2005
• Published: 12/01/2005
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: Steller Micro Devices
• Original Assignee: Stellar Micro Devices, Inc.
• Inventors: Potter, Curtis Nathan
• Granted Patent: US 7,576,427 B2
• Time in Patent Office: Days
• US Class Current: 257/704
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: H01L 21/50 Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/85 using a wire connector
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 23/055 the leads having a passage through the base H01L23/057 takes precedence
• CPC Class Codes: H01L 23/10 characterised by the material or arrangement of seals between parts, e.g. between cap and base of the container or between leads and walls of the container
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/163 : Connection portion, e.g. seal
• CPC Class Codes: H01L 2924/207 : Diameter ranges

Abstract

A cold welded hermetic micro or nano package sealed in an inert atmosphere with optional force maintenence means for ensuring permanent closure. A package cap 410 coated with precursor weld material is sealed to a package base 405 containing integral device 445 then cold welded with an external force mechanism to compress and flow cold seal preform material 435 creating a hermetic peripheral seal in an inert or vacuum atmosphere. Arrays of devices can be sealed with individual caps or arrays of caps which are interconnected.

Claims

1. A structure and method for hermetically sealing a device inside micro- or nano-package wherein:

a package base and cap are sealed by compressive force sufficient to effect a hermetic cold-weld seal and the sealing is effected with compressive force means with base, cap, and device inside a chamber so that the inert, rarified gas or vacuum ambient environment of that chamber is captured inside the sealed package.

2. The structure and method of claim 1 wherein the device is a MEMS OR NEMS.

3. The structure and method of claim 1 wherein a cold-weldable preform, gasket, wire ring or other highly deformable, flowable structure is provided by plating, vacuum deposition or other means.

4. The structure and method of claims 1 and 3 wherein a precursor material is provided by vacuum deposition, cladding, plating or other means on both package cap and base in the area where the cold weld is to accomplished.

5. The structure and method of claim 1 wherein the device has been formed on or is integral to the package base or cap.

6. The structure and method of claim 1 wherein the package cap or base contains a mechanical design structure for enhancing the surface expansion of a cold weldable material.

7. The structure and method of claim 1 wherein a re-entrant cavity is provided in a package cap or base suitable for use as a force maintenance means for holding cap to base.

8. The structure and method of claim 1 wherein an additional force is applied by a perimeter epoxy seal or other means to keep the cold-welded base and cap together after sealing.

9. The structure and method of claim 1 wherein a getter is provided on the package cap, base or device by mechanical attachment, or deposition outside or inside the sealing chamber environment.

10. A structure and method for hermetically sealing multiple devices inside multiple micro- or nano-packages wherein:

the multiple devices are provided on a common substrate;

an array of caps, either separated or joined together, are sealed to the device substrate so as to enclose the individual devices and effect hermetic cold-weld seals; and

the sealing is effected with the substrate and devices, array of caps and compressive force means inside a chamber so that the inert, rarified gas or vacuum ambient environment of that chamber is captured inside the sealed packages.