High-pressure polycrystalline diamond as a cost effective heat spreader

Abstract

Diamond is an ideal material for heat spreading applications; CVD PCD is many times more expensive than high pressure PCD because it grows much slower and the material cost is higher. High-pressure PCD can be produced in large quantities and molded into shapes at a reasonable price. Novatek's patented high pressure synthesis process produces PCD with a conductivity of 700 W/m/spl deg/K, almost twice that of copper. Diamond heat spreaders are most effective in applications producing high heat flux densities. Diamond becomes far more conductive than metals at cryogenic temperatures. The thermal junction between the IC and the heat sink is a predominant thermal resistance. High pressure diamond has favorable thermal expansion and stiffness coefficients and is easily pre-metalized insitu, making it a good material for direct bonding to the IC.