Flip Chip Lids provide thermal management.
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Press Release Summary:
Compliant with RoHS, AlSiC metal matrix composite lids are available in large format for SiP devices used in workstations, servers, video processing, data communications products, and Internet routers. AlSiC cast products can incorporate functional design features such pockets for memory chips, ridges for reinforcement, bosses for alignment, and cavities or pedestals for die. Surface supports laser marking, paint, ink, and screen printing, as well as plating anodization.
Original Press Release:
CPS AlSiC Large Format Integrated Heat Spreader Flip Chip Lids Provide Thermal Management for Improved Performance and Reliability
Large format AlSiC flip-chip lids used for System in Package IC improve device reliability and enable new packaging approaches
CPS Technologies Corporation, the worldwide leader in the design and production of metal matrix composites addressing thermal management and structural reliability, offers AlSiC (Aluminum Silicon Carbide) metal matrix composite lids in large format for Systems in Package (SiP) devices used in high-performance workstations, servers, video processing, data communication products, internet routers and at high frequency and RF packaging applications where performance and reliability are critical.
The SiP technology combines multiple die with multiple functionalities into a single package including components usually found on motherboards to create highly integrated products for optimized cost, size and performance. The die is most often protected using a simple stamped copper heat spreader, leaving the rest of the components exposed. In some cases it is desired to lid the entire system. AlSiC becomes the ideal material choice for a completely lidded system over copper lid systems because AlSiC material is lighter weight, has a higher stiffness, a compatible thermal expansion, and net-shape casting capability.
In large SiP systems, > 40 mm square, lid material density has a significant influence on the maximum weight per solder ball requirements. AlSiC has a density of 1/3 of Cu, so large area lids can be considered without exceeding these critical weight limits. Material stiffness is also critical in these large format systems to provide die protection during assembly, or during application of the customer supplied heat sinks. The device compatible Thermal Expansion Coefficient (TEC) of AlSiC is more important in large SiP in reducing system warping and thermally induced stresses damage due to TEC differences. AlSiC has a thermal expansion that matches GaAs, close to Si, and matches substrate materials in SiP assemblies. AlSiC-9 grade of material is especially well suited to ceramic ball grid array flip chip applications. Using copper with a nearly two times greater TEC the only smaller lids on smaller ICs can be considered because of these thermal stress issues.
The AlSiC fabrication process enables greater dimensional and shape capability that is necessary in larger format lids that cannot easily be achieve in stamped copper lids, and is too costly in machined copper. AlSiC provides a more stable thermal path because flatness is maintained during thermal excursions as a result of CTE compatibility, dimensional control, and the 1/3 greater stiffness of AlSiC as compared to Cu. AlSiC cast product can incorporate functional design features such pockets for memory chips, capacitors, resistors, ridges for reinforcement, bosses for alignment, as well as cavities or pedestals for the die. Depth of these features is tightly controlled to minimize the bond length thickness and assembly and thermal dissipation variability between assemblies.
The AlSiC cast surface supports various identification methods including, laser marking, paint, ink, and screen printing, as well as plating anodization and other surface metallization schemes typically applied to aluminum.
AlSiC meets the requirements of the Restriction of Hazardous Substances Directive (RoHS compliant) of the European Parliament.
About CPS Technologies Corporation
CPS Technologies Corporation (NASDAQ Symbol "CPSH.OB") is the worldwide leader in the design and high-volume production of metal matrix composites. With over 30 years combined experience, CPS engineers and scientists use a net-shape fabrication process, including patented QuickSet(TM) injection molding and QuickCast(TM) infiltration. AlSiC components are utilized in applications in the wireless communications infrastructure, high-performance microprocessor, motor controller, and other microelectronic markets. CPS' customers include TI, Motorola, HP, Agilent and Amkor. For more information on CPS' AlSiC components, contact CPS at 1 (508) 222-0614 x 242; e-mail marko@alsic.com, or visit www.alsic.com.
