Semiconductor Bonding Structure for Stable Interface Heat Dissipation
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Solution Overview
Problem
The heat dissipation capability of semiconductor devices degrades over time at the bonding interfaces between the conductor layer and semiconductor elements, leading to reliability issues.
Innovation Solution
A semiconductor device configuration with a support member, a support layer, and joining layers made of materials like copper and aluminum, where the semiconductor elements are bonded via solid-phase diffusion, enhancing the bonding strength and heat conduction efficiency by forming protrusions and optimizing the bonding interface geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If semiconductor elements are bonded to the conductor layer via a solder layer, then heat dissipation capability is improved, but the heat dissipation capability degrades in the long term at the bonding interfaces
Solution Approach 1:
The invention employs a composite bonding structure consisting of a solder layer and a copper foil layer bonded together. The solder layer (containing Sn, Ag, Cu, and Ni) provides strong metallurgical bonding to the semiconductor element, while the copper foil layer provides excellent thermal conductivity and structural stability. This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both immediate heat dissipation performance and long-term bonding interface stability.
Solution Approach 2:
The copper foil layer acts as an intermediary between the solder layer and the conductor layer. It mediates the thermal and mechanical stresses at the bonding interface, preventing direct stress concentration between the solder and conductor layer. This intermediary structure stabilizes the bonding interface over time while maintaining effective heat dissipation pathways from the semiconductor element through the solder-copper composite to the conductor layer.
2Temperature
If the bonding interface area is increased to improve heat dissipation, then heat conduction efficiency is improved, but shear stress concentration increases
Solution Approach 1:
The invention applies local quality by creating a copper foil layer with specific local properties at the bonding interface. The copper foil has high thermal conductivity locally at the interface region to enhance heat conduction, while its ductile nature locally absorbs shear stresses. This localized optimization of material properties allows the bonding interface to simultaneously achieve improved heat conduction efficiency and reduced shear stress concentration compared to a uniform solder layer design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration stabilizes the heat dissipation capability at the bonding interfaces, reduces shear stress, and improves the long-term reliability and efficiency of heat conduction, while also enhancing the dielectric strength and allowing for higher current flow.
Implementation Method 1
the heat generated from the semiconductor elements during the use of the semiconductor device is conducted to the conductor layer via the solder layer
Implementation Method 2
the semiconductor elements are bonded via solid-phase diffusion, enhancing the bonding strength
Data Source
AI summary
A semiconductor device includes a support layer, a semiconductor element including an element metal layer facing the support layer, and a joining layer interposed between the support layer and the element metal layer. The element metal layer includes a first edge extending in a first direction orthogonal to a thickness direction of the semiconductor element. The joining layer includes a second edge located closest to the first edge and extending in the first direction. When the second edge is spaced apart from the element metal layer as viewed in the thickness direction, the distance from the first edge to the second edge in a second direction orthogonal to the thickness direction and the first direction is equal to or less than twice the thickness of the joining layer.