Copper Molybdenum Alloy
Copper molybdenum’s remarkable properties include highly efficient thermal and electrical conductivity, suitable coefficient of thermal expansion (CTE) closely matched with high power and frequency electronic components, excellent hermeticity, and solderability. These properties make copper moly alloys particularly suitable for heat sinks, heat spreaders, and baseplates applied in IGBT, LDMOS, and GaN/GaAs-based devices.
The most typical molybdenum copper composites ratios are 70/30 and 80/20. Other ratios include MoCu 50/50, 60/40, and 85/15. Our molybdenum copper composites materials include molybdenum copper plate, sheet, foil, rod, tube, and machined parts. Copper moly alloys are sintered from pure molybdenum and oxygen-free copper using powder metallurgy.
CHEMETAL USA has decades of experience in manufacturing all Mo/Cu composite ratios using either solid or infiltration sintering. Our exacting standards and quality control at all manufacturing stages ensure unsurpassed purity and precision in our Copper molybdenum materials. Our advanced Mo Cu alloy materials can meet specifications as precise as 6-micron grain size, 0.01 mm porosity, and less than 5.0 x 10 -9 Pa.m3 /s outgassing rate. The particle size and purity of these powders, the high temperature of sintering and annealing, and the deforming rates applied at each reduction are all under strict quality control and inspection protocols.
Moly Copper Alloys
|Mo85Cu15||Mo 85% Cu 15% wt|
|Mo80Cu20||Mo 80% Cu 20% wt|
|Mo75Cu25||Mo 75% Cu 25% wt|
|Mo70Cu30||Mo 70% Cu 30% wt|
|Mo60Cu40||Mo 60% Cu 40% wt|
|Thermal Conductivity||170-300 W/m·K|
|Electrical Conductivity||38-66 IACS % Min.|
|Composition||Density||Electrical Conductivity||CTE||Thermal Conductivity||Hardness||Electrical Resistivity|
|g/cm³||IACS % Min.||10-6 K-1||W/m · K-1||HV||μΩ cm|
Properties of Molybdenum Copper as Thermal Management Material
Compatible Thermal Expansion Coefficient
Molybdenum copper (MoCu) is an ideal material for heat sinks and heat spreaders in high frequency and high power electronic devices when the compatibility of Coefficient of Thermal Expansion (CTE) is a critical concern.
The CTE of molybdenum copper can be adjusted to be compatible with common semiconductor materials, such as Si; GaN; and GaAs; as well as ceramic packaging materials, including Al2O3; BeO; AlN; and SiC. This is because molybdenum copper materials may be composited in a wide range of Mo and Cu ratios from Mo60Cu40 to Mo85Cu15. Each ratio defines a specific CTE ranging from 5.6/10-6 K to 11.5/10-6 K. This range fully covers the CTEs range, 3×10-6 K to 10×10-6 K, of semiconductor and ceramic packaging substrate materials. The operational reliability and lifespan of such components is greatly enhanced by the reduction of thermal stresses generated by surficial high temperature variation.
Outstanding Electrical and Thermal Conductivity
The excellent thermal spreading and electrical conducting properties of molybdenum copper make it ideally suited for heat sinks and heat spreaders in high power, high-frequency devices. MoCu containing 15% to 18% copper exhibits outstanding thermal conduction as high as 160 W·m-1 ·K-1 and electrical conduction up to 10 g.cm-3.
While copper tungsten composite materials with comparable copper fractions exhibit relatively high thermal and high electrical conductivity, molybdenum copper is favored for use as a heat spreader because of its lower specific density and superior machinability than copper tungsten, both critical concerns for weight-sensitive and highly integrated electrical devices. Therefore, molybdenum copper is an exceptionally well-suited material for heat sinks and heat spreaders by virtue of its superb heat dissipation, electrical transmission, weight sensitivity, and machinability.
Other Unique Properties
In addition to its unsurpassed qualities as detailed above, molybdenum copper composite material yield an outgassing rate of less than 5.0 x 10-9 Pa.m3/s, allowing MoCu heat sinks and heat spreaders to work comparatively well in vacuum environments.
They also lend themselves to easy removal of Mo and Cu oxides and impurities, including N2, H2, and C, during the manufacturing process.
Moreover, internal pore size can be controlled to average tolerances as small as 0.01 mm. The grain sizes of molybdenum copper range from 6 to 15 µm, which, along with other attributes, assures low porosity.
In addition, Mo Cu alloy is an exceptional electromagnetic interference (EMI) shielding material for vacuum electrical devices which demands both a high EMI/RFI reduction level and CTE compatibility. This is because molybdenum and copper are all non-ferromagnetic metals.
Molybdenum Copper Machining
As an ISO certified molybdenum copper supplier and manufacturer with advanced machining facilities, CHEMETAL USA is capable of offering various types of molybdenum copper products that all meet a consistently high standard. With years of experience in handling molybdenum alloy materials, our highly-trained technicians are skilled in offering the following machining services for a variety of molybdenum tungsten materials.
- EDM Machining
Copper Clad Molybdenum Laminates
Copper clad molybdenum laminates are alternately layered structures comprised of various Mo/MoCu and Cu combinations, with one or two Mo or MoCu composites as core layers. We have the capacity to produce all models of 3 and 5 layers Mo and Cu laminates, including CMC, CPC, and SCMC, in various Mo: Cu or MoCu:Cu thickness ratios.
CMC (Cu/Mo/Cu) is three-layer structure available in varying layer thickness ratios, including 1:1:1, 1:2:1, 1:3:1, 1:4:1, and 13/74/13. CMC has better CT and CET than Mo and higher CT than MoCu at the same level of CET. By bonding two copper layers to molybdenum, the laminated CMC attains higher thermal and electrical conductivities so CMC becomes more machinable than pure molybdenum and molybdenum copper composites. Therefore, it is the preferred enhanced thermal management material to replace MoCu composites or Mo made baseplate for LGBT and other high power density devices.
The molybdenum copper core layer of CPC achieves improved thermal conductivity over CMC without sacrificing CTE advantages. It is thus a further enhanced three-layer laminate based on CMC. The common CPC model is CPC 141, which has the Mo70Cu30 core layer and 1:4:1 thickness ratio. Compared with CMC, CPC achieves more efficient heat dissipation and distribution and is more reliable for use in heat spreaders in LDMOS and GaN/GaS based devices.
SCMC (Cu/Mo/Cu/Mo/Cu) is five layered molybdenum and copper laminated structure, consisting of two molybdenum core layers and three copper layers. Our advanced SCMS 51515 can be rolled through the evenly distributed tunnels across the Mo layer so as to connect to each other, helping to further consolidate the bonding effect of all layers. The five layers of the Mo and Cu bonded structure of SCMS 51515, and the 80% wt copper content in the laminate, can achieve 290 W/(M.K) thermal conductivity and the same high electrical conductivity as all other types of MoCu laminates.