Sputtering Target Bonding via Mechanical Interlocking
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Solution Overview
Problem
Current methods for bonding sputtering target segments to backing bodies, such as diffusion bonding and soldering, are expensive, complex, and can lead to material deterioration, thermal issues, and difficulties in recycling due to the need for protective atmospheres and additional processing steps, as well as potential contamination and waste of high-purity materials.
Innovation Solution
A method involving interlocking of components with protrusions and undercuts on their connection surfaces, achieved through pressing in a mould, which creates a strong, heat-resistant bond without the need for solder or protective atmospheres, allowing for easy recycling and reduced material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If diffusion bonding is used to bond target segments to backing body, then bonding strength is improved, but process complexity and cost increase due to requirement of vacuum or protective atmosphere
Solution Approach 1:
The connection surface is segmented into protruding parts and other parts, creating a structured interface that enables mechanical interlocking through undercuts. This segmentation allows the softer material to flow into and lock within the undercut structures of the harder material during pressing, achieving strong bonding without complex atmospheric control
Solution Approach 2:
The invention replaces the thermal-diffusion mechanism of diffusion bonding with a mechanical interlocking mechanism. By using protrusions with undercuts and applying pressure to cause plastic deformation, the bonding is achieved through mechanical interlocking rather than atomic diffusion, eliminating the need for vacuum or protective atmosphere
2Strength
If high temperature is used for diffusion bonding, then bonding strength is improved, but target material properties deteriorate due to grain growth
Solution Approach 1:
The invention changes the bonding mechanism from thermal-diffusion to mechanical-interlocking, allowing bonding to occur at lower temperatures. By applying pressure to cause plastic deformation of the softer material into the undercuts of the harder material, strong bonding is achieved without subjecting the target material to high temperatures that would cause grain growth or property deterioration
3Strength
If soldering is used to bond target segments to backing body, then bonding is achieved, but thermal connection deteriorates due to local overheating and solder melting
Solution Approach 1:
The invention uses the softer material (which could be considered a sacrificial bonding layer) to flow into and fill the undercuts of the harder material. This softer material acts as a permanent mechanical lock rather than a temporary solder, maintaining thermal connection integrity even under high thermal loads since it is structurally integrated rather than relying on melting point
Solution Approach 2:
The undercut geometry creates a mechanical interlock that prevents delamination and maintains thermal connection. The curved or angled undercut surfaces allow the softer material to flow in and create a interlocked structure that resists thermal stress and prevents local overheating issues
4Strength
If grooves and ridges are created in backing body and target segments, then interfacial area increases and mechanical interlocking is improved, but material waste increases due to mechanical removal
Solution Approach 1:
The protrusions with undercuts are pre-formed on the connection surfaces before bonding. During the pressing operation, the softer material naturally flows into these pre-prepared undercut structures, eliminating the need for subsequent groove creation steps and preventing material waste associated with mechanical removal
5Strength
If diffusion bonding or soldering is used, then bonding is achieved, but recycling difficulty increases due to multi-material contamination
Solution Approach 1:
The bonding method creates a mechanical interlock that maintains material integrity and minimizes contamination. The softer material fills the undercuts of the harder material in a controlled manner, creating a bonded joint that can be more easily separated and recycled compared to diffusion-bonded or soldered joints that create complex multi-material contamination
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 method provides a cost-effective, simple, and reliable bonding process that maintains the integrity of high-purity materials, enhances thermal connection, and facilitates easier recycling by eliminating the need for solder and diffusion bonding, while allowing for customizable curvature and reversible bonding for repeated use.
Implementation Method 1
pressing the first component and the second component towards each other resulting in a plastic deformation of the material of at least one of the region of the connection surface of the first component and the region of the connection surface of the second component, filling at least partly at least one undercut
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention describes a method for bonding components of a sputtering target, comprising the following steps: providing a first component and a second component, the harder of which has undercut protrusions; positioning them against each other; and pressing them towards each other resulting in a plastic deformation of the material of at least one of the two components, filling the undercuts thereby creating interlocking, as well as the bonded assembly so created, and its recycling. No step creating bonding other than interlocking on a major part of the bonded surface area is necessary.