Interfacial design of Cu-based composites prepared by powder metallurgy for heat sink applications

Abstract

Thermal aspects are becoming increasingly important for the reliability of the electronic components due to the continuous progress of the electronic industries. Therefore, the effective thermal management is a key issue for packaging of high performance semiconductors. The ideal material working as heat sink and heat spreader should have a CTE of (4-8) × 10 −6 K −1 and a high thermal conductivity. Metal matrix composites offer the possibility to tailor the properties of a metal by adding an appropriate reinforcement phase and to meet the demands in thermal management.Copper/SiC and copper/diamond composites have been produced by powder metallurgy. The major challenge in development of Cu/SiC is the control of the interfacial interactions. Silicon carbide is not stable in copper at the temperature needed for the fabrication of Cu/SiC. It is known that the bonding between diamond and copper is very weak in the Cu/diamond composite. Improvements in bonding strength and thermo-physical properties of the composites have been achieved by • a vapour deposited molybdenum coating on SiC powders to control interface reactions, • using atomized Cu(X) alloys with minor additions of carbide formers, e.g. X = Cr, B, to improve the interfacial bonding in Cu-diamond composites.

Infiltrated Cu8Al–Ti alumina composites

“…The calculated value of ⇢ G is then obtained as 4·10 13 per m 2 giving ⌧=29 MPa, corresponding to a di↵erence in tensile flow stress of roughly twice this amount.…”

“…Pure or alloyed copper has thus been combined with ceramics as diverse as TiB 2 [1][2][3][4][5][6][7], Al 2 O 3 [1,[8][9][10][11], several forms of carbon [12][13][14][15][16] or various carbides [17][18][19][20][21]; Ref. [22] gives a review of their processing methods and mechanical properties.…”

Investigation of thermal management materials for automotive electronic control units

“…This makes it unsuitable for automotive applications where weight and cost (Cu is $6.61/kg versus Al $2.02/kg, as found in MetalPrices on 11 Febuary 2010) is a significant concern. The use of SiC or diamond particles as reinforcements in copper was shown as quite attractive to meet the increasing demand for high performance thermal management materials [21]. Table 2 presents the thermal properties of Cu-40%SiC composites reported by Schubert et al [21].…”

“…The use of SiC or diamond particles as reinforcements in copper was shown as quite attractive to meet the increasing demand for high performance thermal management materials [21]. Table 2 presents the thermal properties of Cu-40%SiC composites reported by Schubert et al [21]. As SiC is not stable in contact with copper at elevated temperatures, a vapour deposited molybdenum barrier coating onto SiC was used to control the chemical reaction of Cu and SiC.…”

“…Schubert et al [21] also reported on the thermal properties of the fabricated 42% volume diamond reinforced copper composites. In order to improve wetting of liquid Cu with diamond, several pre-alloyed Cu(X) powders (X = B, Cr, Al, Ti, Zr) were used for the diamond reinforcement.…”