Semiconductor Contact Ribbon with Silver Sinter Layers

The patent applies composite materials by creating a multi-layer ribbon structure consisting of a first layer (aluminum or aluminum alloy) and a second layer (copper or copper alloy) with different thermal expansion coefficients. This composite structure allows the layers to compensate for each other's thermal expansion differences relative to silicon, reducing thermomechanical stress and improving connection reliability under thermal cycling conditions.

The patent replaces the ultrasonic welding process (mechanical-vibrational system) with a diffusion bonding process (thermal-diffusion system). The diffusion bonding method joins the ribbon layers through atomic diffusion at elevated temperatures without the mechanical vibrations and forces that cause pre-damage in ultrasonic welding, thereby improving material integrity while maintaining connection strength.

The patent uses a composite ribbon structure with aluminum (or aluminum alloy) as the first layer and copper (or copper alloy) as the second layer. This composite design combines the advantages of both materials: aluminum provides ease of manufacturing and wider process window, while copper provides superior electrical conductivity. The layered structure allows the material to benefit from both properties simultaneously.

The patent segments the contact structure into multiple layers (aluminum layer and copper layer) that can be independently optimized. The aluminum layer provides large contact area with the semiconductor for low contact resistance, while the copper layer provides high current-carrying capacity. This segmentation allows each layer to contribute to both current-carrying capacity and contact resistance reduction.