Copper Sintered Bonding Junction for Semiconductor Heat Dissipation
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Solution Overview
Problem
Existing bonding techniques for semiconductor devices do not effectively address heat dissipation, which is crucial for preventing thermal damage and ensuring operational stability, especially in high-power devices like IGBTs and GaN-based power devices.
Innovation Solution
A die bonding joining structure is developed using a sintered body of copper powder with interdiffusion portions that straddle the bonding interface between a semiconductor die and a metal support, ensuring efficient heat transfer through copper and gold interdiffusion, enhancing thermal conductivity and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding techniques are used to join semiconductor die to metal support, then bonding can be achieved, but heat dissipation efficiency is insufficient leading to thermal damage risk
Solution Approach 1:
The patent changes the material composition and microstructure parameters of the bonding layer by forming interdiffusion portions with specific crystal structures (copper crystal structure with same crystal orientation) and alloy phases (Cu3Au and gold-copper solid solution). This parameter optimization enables the bonding layer to simultaneously achieve strong bonding and high thermal conductivity, effectively dissipating heat and preventing thermal damage.
Solution Approach 2:
The patent creates a composite structure at the bonding interface consisting of multiple phases: copper interdiffusion portions with single-phase crystal structures, Cu3Au alloy phases, and gold-copper solid solutions. This composite material structure combines the advantages of different phases to achieve both mechanical bonding strength and high thermal conductivity for efficient heat dissipation.
2Loss of energy
If high thermal conductivity materials are used in bonding layer, then heat dissipation improves, but bonding strength may be compromised
Solution Approach 1:
The patent applies local quality by creating distinct regions with different properties at the bonding interface. The interdiffusion portions have copper crystal structures optimized for thermal conduction, while the Cu3Au and gold-copper solid solution regions provide mechanical bonding strength. Each local region is optimized for its specific function, and together they achieve both strong bonding and high heat dissipation efficiency.
Solution Approach 2:
The patent performs preliminary action by pre-forming the interdiffusion portions with specific crystal structures and alloy phases during the bonding process. This preliminary structuring of the bonding layer ensures that both thermal conduction pathways and mechanical bonding interfaces are established before the device undergoes thermal stress, preventing thermal damage while maintaining bonding strength.
3Ease of manufacture
If simple copper bonding is used, then manufacturing is simple, but heat dissipation and bonding strength are insufficient for high-power devices
Solution Approach 1:
The patent optimizes parameters including the crystal structure orientation of copper interdiffusion portions, the composition and distribution of Cu3Au and gold-copper solid solution phases, and the microstructure of the bonding layer. These parameter changes enhance thermal conductivity and bonding strength while maintaining compatibility with existing bonding processes, achieving both ease of manufacture and operational stability for high-power devices.
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 structure effectively dissipates heat generated by semiconductor devices, reducing the risk of thermal damage and improving operational stability and reliability, particularly in high-power applications.
Implementation Method 1
interdiffusion portions (41) in which copper contained in the support (20) and copper contained in the sintered body (32) are diffused to each other are formed so as to straddle a bonding interface (40)
Implementation Method 2
interdiffusion portions (44) in which gold contained in the bottom surface of the die (10) and copper contained in the sintered body (32) are diffused to each other are formed so as to straddle a bonding interface (43)
Implementation Method 3
a bonding joining structure (1) in which a heat generating body and a support (20) comprising a metal are joined to each other via a joint portion (30) composed of a sintered body (32) of copper powder
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(c)
AI summary
Provided is a bonding joining structure in which a heat generating body and a support (20) including a metal are joined to each other via a joint portion (30) composed of a sintered body (32) of copper powder (31). The support (20) contains copper or gold, the copper or gold being present in at least an outermost surface of the support (20). An interdiffusion portion (41) in which copper or gold contained in the support (20) and copper contained in the sintered body (32) is formed so as to straddle a bonding interface (40) between the support (20) and the sintered body (32). Preferably, a copper crystal structure having the same crystal orientation is formed in the interdiffusion portion (41) so as to straddle the bonding interface (40).