Metal matrix composite semiconductor power switch assembly

• US 5,365,108 A
• Filed: 11/19/1992
• Issued: 11/15/1994
• Est. Priority Date: 11/19/1992
• Status: Expired due to Fees

• Current Assignee: Sundstrand Corporation (Rtx Corporation)
• Original Assignee: Sundstrand Corporation (Rtx Corporation)
• Inventors: Hughes, Lawrence, Metzler, Mark, Durako, William J. Jr., Anderson, W. Kyle, Hoppe, Richard J., Jackson, Stephen E.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): OSTROWSKI, DAVID M
• Application Number:
  US07/979,088
• Time in Patent Office: 726 Days
• Field of Search: 257/678, 257/691, 257/692, 257/699, 257/708, 257/709, 257/703, 174/52.4, 361/772, 361/775
• US Class Current: 257/678
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4911 the connectors being bonded to at least one common bonding area, e.g. daisy chain
• CPC Class Codes: H01L 23/057 the leads being parallel to the base
• CPC Class Codes: H01L 23/3733 having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures H01L23/3732, H01L23/3737 take precedence
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• 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 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01028 Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01042 Molybdenum [Mo]
• CPC Class Codes: H01L 2924/014 Solder alloys
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/19107 : off-chip wires

Abstract

A power semiconductor assembly, particularly a semiconductor switch assembly which has a number of discrete emitter connection pads, comprised of a metal matrix composite housing and a copper or aluminum post with a cross-sectional area sufficiently large to carry the rated current providing a single-point, external connection to all emitter pads. The post passes through and is supported by an insulating ceramic insert such as aluminum oxide in the wall of the metal matrix composite housing. The post is hollowed out in the region where it passes through the ceramic insert in order to reduce the mechanical stress between the post and the insulating insert as a result of the mismatch in their thermal expansion coefficients. Buses on either side of the semiconductor die provide surfaces for connection from the post to the discrete emitter connection pads on the die.

Claims

1. A semiconductor assembly comprising:

a metal matrix composite housing having a base and a plurality of side walls, one of said side walls having an opening disposed therethrough;

a semiconductor die having a plurality of power electrode pads on an upper surface of said semiconductor die and a power electrode on a lower surface of said semiconductor die;

said lower surface of said semiconductor die mechanically and electrically connected to said base;

a partially hollow conductive post sufficiently large in cross-section to conduct current to said plurality of electrode pads on said upper surface of said semiconductor die;

an insulating insert disposed within said opening disposed through said one of said side walls, said post extending through said insulating insert and insulated from said one of said side walls by said insulating insert;

a conductive bus mechanically secured to said base;

a lead coupling said post to said bus; and

a plurality of leads coupling said bus to said power electrode pads on said upper surface of said semiconductor die.

2. A semiconductor assembly as in claim 1 wherein said partially hollow post is resiliently deformable in a region where said partially hollow post extends through said insulating insert disposed within said side wall.

3. A semiconductor assembly as in claim 2, wherein said insert is a ceramic insulating material such as alumina.

4. A semiconductor assembly as in claim 1, further including a thin metal matrix composite layer disposed between said base of said housing and said lower surface of said semiconductor die power electrode, said thin layer having a coefficient of thermal expansion that is lower than that of said base.

5. A semiconductor assembly as in claim 3, wherein said post is an aluminum post.

6. A semiconductor assembly as in claim 3, wherein said post is a copper post.