Aluminum-Copper Bonded Body Using Ti Diffusion Layer
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Solution Overview
Problem
Existing methods face challenges in bonding aluminum members with copper, nickel, or silver effectively, leading to issues with bonding reliability and heat radiation due to the formation of hard and brittle intermetallic compound layers and difficulties in raising the bonding temperature for complex heat sinks with low solidus temperatures.
Innovation Solution
A bonded body is created using an aluminum alloy with a solidus temperature below the eutectic temperature of the metal member, where a Ti layer is formed at the bonding interface and subjected to solid-phase diffusion bonding to suppress the formation of hard intermetallic compounds and enhance bonding reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aluminum member and metal member (copper, nickel, or silver) are bonded directly, then bonding process is simple, but hard and brittle intermetallic compound layers form reducing bonding reliability
Solution Approach 1:
A Ti layer is introduced as an intermediary between the aluminum member and the metal member (copper, nickel, or silver). This Ti layer acts as a diffusion barrier that prevents the formation of hard and brittle intermetallic compounds while enabling reliable bonding. The Ti layer is formed by sputtering or vapor deposition, creating a three-layer structure (Al-Ti-M) that resolves the contradiction between bonding simplicity and bonding reliability.
2Reliability
If bonding temperature is raised to improve bonding strength, then bonding reliability improves, but complex heat sink structures with low solidus temperatures cannot be bonded
Solution Approach 1:
The invention changes the bonding parameters by introducing the Ti layer, which allows bonding to proceed at lower temperatures (below the solidus temperature of complex heat sink structures). The Ti layer facilitates diffusion bonding at reduced temperatures while maintaining bonding reliability, thus enabling the bonding of complex heat sink structures that would otherwise be impossible to bond at high temperatures.
3Reliability
If Ti layer is formed to suppress intermetallic compound formation, then bonding reliability improves, but manufacturing process complexity increases
Solution Approach 1:
The Ti layer serves as a mediator that can be formed using standard sputtering or vapor deposition techniques, which are well-established in semiconductor and electronics manufacturing. Although an additional layer is added, the process uses conventional equipment and methods, minimizing the increase in manufacturing complexity while achieving significant improvement in bonding reliability.
4Ease of manufacture
If conventional bonding methods are used for aluminum and metal members, then manufacturing cost is low, but bonding quality deteriorates
Solution Approach 1:
The Ti layer is formed using sputtering or vapor deposition, which are standard thin-film deposition techniques already widely used in electronics manufacturing. These processes add minimal cost while dramatically improving bonding quality by preventing intermetallic compound formation and enabling reliable diffusion bonding between aluminum and metal members.
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 reliability and heat radiation properties, allowing for the successful bonding of aluminum and metal members, even in complex heat sink structures with low solidus temperatures, while reducing manufacturing costs.
Implementation Method 1
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
Data Source
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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 solidus temperature is set to be less than a eutectic temperature of a metal element that constitutes the metal member and aluminum. 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.