Thermoelectric Cooler Module with Enhanced Cooling Ability Using a Hybrid Cu Paste and a Si Substrate

A cost-effective and cooling-enhanced thermoelectric cooler (TEC) module is proposed using a new die attachment material and a Si substrate. Although silver paste has been widely used in TEC modules, it has generally shown poor shear strength relative to the high material cost and high temperature of the sintering process. A cost-effective hybrid copper paste (HCP) material, which is composed of Ag-coated Cu flakes, solder powder, and a fluxing resin, is proposed to compensate for the weakness of silver paste. By optimizing the volumetric ratio of the Ag-coated Cu flakes, solder powder, and fluxing resin, screen printing and a curing process for the die attachment were successfully developed. A commercial Ag paste and HCP were applied to interconnect p-type and n-type TE legs with the substrate. Two types of TEC modules were fabricated using a ceramic substrate and a Si substrate. TEC with a module size of 40 mm × 40 mm were fabricated with 128 pairs of p- and n-type TE legs. In this work, the DC resistance and cooling capacity of the TEC module using HCP and a Si substrate were measured and compared with a conventional TEC module. The proposed TEC module is proved to work well with its three advantages: cost reduction, process simplification, and cooling ability.