Bonded metal and ceramic plates for thermal management of optical and electronic devices

• US 8,299,604 B2
• Filed: 08/05/2009
• Issued: 10/30/2012
• Est. Priority Date: 08/05/2008
• Status: Active Grant

• Current Assignee: Vertiv Corporation (Vertiv Holdings Co.)
• Original Assignee: Cooligy Incorporated (Emerson Electric Company)
• Inventors: Datta, Madhav, McMaster, Mark
• Primary Examiner(s): Williams, A O
• Application Number:
  US12/536,402
• Publication Number:
  US 20100035024A1
• Time in Patent Office: 1,182 Days
• Field of Search: 257/700, 257/701, 257/758, 257/E23.098, 257/E23.106, 257/E23.109, 428/172, 428/457, 428/471, 428/472.5, 361/704, 165/185
• US Class Current: 257/700
• CPC Class Codes: C04B 2237/12 Metallic interlayers
• CPC Class Codes: C04B 2237/122 based on refractory metals
• CPC Class Codes: C04B 2237/124 based on copper
• CPC Class Codes: C04B 2237/125 based on noble metals, e.g. silver
• CPC Class Codes: C04B 2237/127 The active component for bonding being a refractory metal
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/366 Aluminium nitride
• CPC Class Codes: C04B 2237/40 Metallic
• CPC Class Codes: C04B 2237/403 Refractory metals
• CPC Class Codes: C04B 2237/405 Iron metal group, e.g. Co or Ni
• CPC Class Codes: C04B 2237/407 Copper
• CPC Class Codes: C04B 2237/408 Noble metals, e.g. palladium, platina or silver
• CPC Class Codes: C04B 2237/592 whereby the interlayer is not continuous, e.g. not the whole surface of the smallest substrate is covered by the interlayer
• CPC Class Codes: C04B 2237/62 Forming laminates or joined articles comprising holes, channels or other types of openings
• CPC Class Codes: C04B 2237/704 of one or more of the ceramic layers or articles
• CPC Class Codes: C04B 2237/706 of one or more of the metallic layers or articles
• CPC Class Codes: C04B 2237/708 of one or more of the interlayers
• CPC Class Codes: C04B 2237/72 Forming laminates or joined articles comprising at least two interlayers directly next to each other
• CPC Class Codes: C04B 2237/74 Forming laminates or joined articles comprising at least two different interlayers separated by a substrate
• CPC Class Codes: C04B 37/026 : consisting of metals or metal salts
• CPC Class Codes: F28F 7/02 : Blocks traversed by passages for heat-exchange media F28D7/0008 takes precedence
• CPC Class Codes: H01L 23/3735 : Laminates or multilayers, e.g. direct bond copper ceramic substrates
• 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 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 1/0203 : Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 1/0207 : using internal conductor planes parallel to the surface for thermal conduction, e.g. power planes
• CPC Class Codes: H05K 1/0272 : Adaptations for fluid transport, e.g. channels, holes
• CPC Class Codes: H05K 1/0306 : Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 2201/0355 : Metal foils
• CPC Class Codes: H05K 2201/064 : Fluid cooling, e.g. by integral pipes
• CPC Class Codes: H05K 3/0061 : onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20
• CPC Class Codes: H05K 3/38 : Improvement of the adhesion between the insulating substrate and the metal
• CPC Class Codes: H05K 3/4629 : laminating inorganic sheets comprising printed circuits, e.g. green ceramic sheets
• CPC Class Codes: H05K 3/4641 : having integrally laminated metal sheets or special power cores
• CPC Class Codes: Y10T 428/24612 : Composite web or sheet
• CPC Class Codes: Y10T 428/31678 : Of metal

Abstract

A ceramic assembly includes one or more electrically and thermally conductive pads to be thermally coupled to a heat generating device, each conductive pad is electrically isolated from each other. The ceramic assembly includes a ceramic layer to provide this electrical isolation. The ceramic layer has high thermal conductivity and high electrical resistivity. A top surface and a bottom surface of the ceramic layer are each bonded to a conductive layer, such as copper, using an intermediate joining material. A brazing process is performed to bond the ceramic layer to the conductive layer via a joining layer. The joining layer is a composite of the joining material, the ceramic layer, and the conductive layer. The top conductive layer and the joining layer are etched to form the electrically isolated conductive pads. The conductive layers are bonded to the ceramic layer using a bare ceramic approach or a metallized ceramic approach.

Claims

1. A device comprising:

a. a first copper layer;

b. a ceramic layer;

c. a second copper layer;

d. a first active brazing alloy layer bonded between the first copper layer and the ceramic layer to form a first joining layer, wherein the first copper layer and the first joining layer are configured to form a plurality of electrically isolated conductive pads, wherein each of the plurality of electrically isolated pads includes an etched wall extending from a first surface of the first copper layer through the first copper layer and the first joining layer to a first surface of the ceramic layer, the first surface of the first copper layer is distal from the first joining layer, and the first surface of the ceramic layer is proximate to the first joining layer, further wherein a slope of the etched wall through the first joining layer is steeper than a slope of the etched wall through the first copper layer; and

e. a second active brazing alloy layer bonded between the ceramic layer and the second copper layer to form a second joining layer.

2. The device of claim 1 wherein the first copper layer and the first joining layer are etched to form a plurality of electrically isolated conductive pads, further wherein each of the plurality of electrically isolated pads are electrically isolated from each other and from the second copper layer by the ceramic layer.

3. The device of claim 1 wherein the ceramic layer comprises beryllium oxide, aluminum oxide, or aluminum nitride.

4. The device of claim 1 wherein the first active brazing alloy layer and the second active brazing alloy layer comprise a copper-based active brazing alloy, a copper-silver-based active brazing alloy, or an indium-copper-silver-based active brazing alloy.

5. The device of claim 1 wherein the first active brazing alloy layer is comprised of an active joining material paste and the second active brazing alloy layer is comprised of the active joining material paste, or the first active brazing alloy layer is comprised of an active joining material foil and the second active brazing alloy layer is comprised of the active joining material foil.