International Edition

  • Kuprion’s Engineered ActiveCopperTM Materials Achieve World Record – 4000 Thermal Shock Cycles for its CTE Matched DBC AlN Systems


    Heat dissipation is one of the key challenges for high-power electronics due to high heat generation and
    elevated operational temperatures, on the order of 300oC. Direct bond copper (DBC) substrates,
    composed of aluminum nitride (AlN) or silicon nitride (SiN) ceramics with copper (Cu) directly bonded to
    one or both sides, are used to dissipate heat due to their high thermal conductivity (200 W/mK and 50 W/mK respectively), and consequently high heat dissipation ability. However, to firmly adhere copper
    to such ceramic surfaces requires a high-temperature process, as high as 1000oC.

    The high thermal expansion mismatch (CTE) between Cu (17 ppm) and AlN (4.5 ppm) or SiN (3 ppm)
    leads to high mechanical stresses on cool-down that can cause cracking and failure after just a few
    cycles of heating and cooling. High-power devices commonly experience a large number of thermal
    cycles during their lifespan. Therefore, managing thermal mismatch is an area of extreme importance to
    ensure high reliability and long life in the field.

    While SiN is strong enough to handle thousands of thermal shock cycles, its thermal conductivity is 5
    times lower than AlN. However, AlN is weaker than SiN and tends to yield to mechanical stresses and
    breaks quickly, which has greatly limited its utility.

    Kuprion’s ActiveCopperTM Materials Provide a Robust & Less Costly Solution
    Kuprion’s engineered ActiveCopperTM sintering materials exhibit extremely high conductivity, up to 393
    W/m*K, and easily bond directly to AlN and other ceramics at temperatures below 250oC. Kuprion’s
    innovative ActiveCopperTM materials can be formulated with CTE values that closely match a variety of
    ceramics and wide-bandgap (WBG) substrates including silicon carbide (SiC) and gallium nitride (GaN).
    Recent test results show superior reliability and performance by surviving more than 4,000 thermal
    shock cycles in air (-55oC to +150oC) without delamination or voiding (CSAM), achieving a world record for DBC AlN.

    Kuprion’s ActiveCopperTM formulations can be deposited in a wide range of thicknesses, from 100 to at
    least 600 microns, using standard stencil and screen-printing techniques. Once cured, Kuprion’s
    ActiveCopperTM materials convert to bulk copper that can be easily soldered or bonded to using standard industry solders and adhesives. It can even be electroplated and etched using standard chemistries.

    Kuprion’s technology enables lower processing temperatures and significantly reduces DBC AlN
    fabrication costs, opening up a wide range of opportunities for new multi-chip power module designs
    and heterogeneous integration of new semiconductor packages with much improved operating

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