Optimized Organic Tunnel for Large Area Connection of Power Module

The third-generation semiconductor materials, characterized by wide bandgaps, exhibit the capability to operate under high voltage, large current, and high switching frequencies. Presently, sintered silver and sintered copper are commonly employed as packaging interconnects for high-power chips. However, for packaging materials of high-power density chips, attributes such as high thermal conductivity, electrical conductivity, and reliability are of paramount importance. The thermal conductivity between power modules and heat sinks also constitutes a bottleneck in realizing the full potential of power chips. The application of sintered silver in power module packaging incurs high costs and is accompanied by issues such as silver electrochemical migration. This study focuses on the interconnection process and reliability between high-power density chip packaging modules and heat sinks. By printing a layer of paste covering the entire
$50\mathrm{x}50\text{mm}^{\wedge}2$
substrate surface, as well as printing a layer containing organic tunnels, the reliability issues of large-area copper sintering are investigated. The introduction of organic dispersal tunnels addresses the low strength problem associated with large area sintering by reducing organic residues within the sintering structure, thereby enhancing the interconnection strength of sintered joints. Microstructural observations of the sintered joints reveal a well-connected interface between the sintered joint and substrate. The whole copper block was divided into four pieces. Furthermore, shear strength testing of the interconnect joints indicates that the introduction of organic dispersal tunnels significantly enhances joint strength, with shear strength increasing from 28.4 MPa to 37.3 MPa. The introduction of organic dispersal tunnels effectively addresses the issue of low strength in large-area sintered interconnect joints, thereby improving the reliability of module operation.