Laminated Solder Connection for Semiconductor Heat Dissipation
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Solution Overview
Problem
The existing semiconductor devices face challenges in achieving effective heat radiation and reliability due to void formation in the connection member between the semiconductor element and the heat radiating plate, leading to stress application and reduced connection reliability, as well as potential electrical short circuits from scattered solder particles.
Innovation Solution
A laminated connection member structure comprising a high melting point solder as the second member and low melting point solders for the first and third members, with the second member's larger area and higher melting point allowing stress relaxation and efficient heat transfer, while the first and third members' smaller areas prevent void formation and protrusion, ensuring reliable bonding and reduced risk of electrical short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer connection member is used to connect the semiconductor element and heat radiating plate, then the structure is simple, but voids form during bonding causing stress concentration and reduced reliability
Solution Approach 1:
The connection member is divided into three distinct layers (first member, second member, third member) with different materials and functions. This segmentation allows each layer to address specific issues: the first and third members prevent void formation at interfaces, while the second member provides stress relief, collectively improving connection reliability without requiring excessive complexity.
Solution Approach 2:
The connection member uses a composite structure combining different materials (e.g., solder alloys with varying melting points, or metal/ceramic combinations) in each layer. This composite approach enables optimization of each layer's properties to prevent voids, manage stress, and ensure reliable thermal and electrical connection between the semiconductor element and heat radiating plate.
2Quantity of substance
If solder particles scatter during bonding process, then the bonding area increases, but electrical short circuits occur between adjacent elements
Solution Approach 1:
The connection member structure is designed with containment features and appropriate layer configurations that prevent solder particles from scattering outward during the bonding process. By anticipating the potential harm of solder scattering, the design incorporates preventive measures that keep solder within designated areas, eliminating electrical short circuit risks while maintaining adequate solder distribution for reliable bonding.
3Loss of energy
If the connection member area is increased to improve heat transfer, then heat radiation efficiency improves, but stress on the semiconductor element increases
Solution Approach 1:
The connection member is segmented into multiple layers with the second member specifically designed to provide stress relief. This allows the overall connection area to be increased for improved heat transfer, while the intermediate layer absorbs and distributes mechanical stress, preventing excessive stress concentration on the semiconductor element.
Solution Approach 2:
The connection member uses materials with different physical properties (melting points, thermal expansion coefficients, elastic moduli) in each layer. By changing material parameters across layers, the structure achieves both large area coverage for heat dissipation and stress management through selective material properties that accommodate thermal and mechanical expansion differences.
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
The laminated connection member structure enhances heat radiation efficiency, reduces stress on the semiconductor element, and prevents void formation and electrical short circuits, thereby improving the reliability and performance of the semiconductor device.
Implementation Method 1
heat generated in the semiconductor element is efficiently transferred to the heat radiating plate
Implementation Method 2
the semiconductor element and the heat radiating plate are connected by an alloy with high thermal conductivity such as solder
Data Source
AI summary
A semiconductor device includes a substrate, a semiconductor element disposed on the substrate, a heat radiating plate disposed on the substrate and covering the semiconductor element, and a connection member connecting an upper surface of the semiconductor element and a lower surface of the heat radiating plate, wherein the connection member includes a first member being in contact with the upper surface of the semiconductor element and having a first melting point, a second member being in contact with the first member, having a larger area than the first member, and having a second melting point higher than the first melting point, and a third member interposed between the second member and the heat radiating plate, having an area smaller than the second member, and having a third melting point lower than the second melting point.