Ti Interlayer Bonding Aluminum Silicon Alloy Copper Heat Sinks
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Solution Overview
Problem
Existing methods face challenges in bonding aluminum members with a high silicon content to copper, nickel, or silver members, leading to poor bonding reliability due to the formation of hard and brittle intermetallic compound layers and difficulties in achieving satisfactory heat radiation properties in complex heat sinks.
Innovation Solution
A method involving the formation of a Ti layer at the bonding interface between aluminum and metal members, followed by solid-phase diffusion bonding, which suppresses the formation of thick intermetallic compound layers and enhances bonding reliability by controlling the Si concentration in the aluminum alloy and using copper, nickel, or silver as the metal members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Ti layer is formed at the bonding interface between aluminum member and metal member, then bonding reliability is improved by suppressing intermetallic compound layer formation, but manufacturing complexity increases due to additional layer formation step
Solution Approach 1:
A Ti layer is formed on the metal member surface before bonding with the aluminum member. This preliminary action prevents the formation of thick, brittle intermetallic compound layers during the bonding process, thereby improving bonding reliability while managing manufacturing complexity through advance preparation
Solution Approach 2:
The Ti layer acts as an intermediary layer between the aluminum member and the metal member (Cu, Ni, or Ag). This intermediate Ti layer controls the diffusion process and suppresses the formation of excessive intermetallic compounds, improving the overall bonding reliability of the joint
2Reliability
If Si concentration in aluminum alloy is controlled within 1-25 mass%, then bonding reliability is improved by suppressing intermetallic compound formation, but material selection flexibility is reduced
Solution Approach 1:
The Si concentration in the aluminum alloy is controlled within a specific range of 1-25 mass%. This parameter change suppresses the formation of thick, brittle intermetallic compound layers during bonding, thereby improving bonding reliability. The patent specifies this concentration range to optimize the balance between bonding performance and material properties
Solution Approach 2:
The invention uses composite material strategy by combining aluminum alloy (with controlled Si content) and metal member (Cu, Ni, or Ag) with a Ti intermediate layer. This composite structure achieves improved bonding reliability by controlling the chemical composition and layer structure to suppress harmful intermetallic formation
3Temperature
If complex heat sink structure is manufactured with aluminum alloy, then heat radiation properties are enhanced, but bonding difficulty increases due to high Si content
Solution Approach 1:
The Ti layer is applied locally at the bonding interface of the heat sink rather than throughout the entire component. This local treatment suppresses intermetallic compound formation at the critical bonding zone while maintaining the high Si content (1-25 mass%) in the aluminum alloy heat sink body, thereby preserving both heat radiation efficiency and bonding reliability
Solution Approach 2:
The Ti layer serves as an intermediary between the complex heat sink structure and the metal member, enabling reliable bonding of heat sinks with high Si content aluminum alloys. This intermediate layer resolves the bonding difficulty caused by high Si content while preserving the heat radiation properties of the complex heat sink structure
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 approach results in a bonded body with improved bonding reliability and enhanced heat radiation properties, suitable for complex heat sinks and power module substrates, particularly in high-power semiconductor applications.
Implementation Method 1
solid-phase diffusion bonding
Data Source
Figure 1
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AI summary
The present invention is a bonded body in which an aluminum member constituted by an aluminum alloy, and a metal member constituted by copper, nickel, or silver are bonded to each other. The aluminum member is constituted by an aluminum alloy in which a Si concentration is set to be in a range of 1 mass% to 25 mass%. A Ti layer is formed at a bonding portion between the aluminum member and the metal member, and the aluminum member and the Ti layer, and the Ti layer and the metal member are respectively subjected to solid-phase diffusion bonding.