Sputtering Target Design for Thermal Stability
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Solution Overview
Problem
Conventional sputtering targets face issues with mechanical stability and cooling efficiency, particularly during high-power applications, where targets with fine structures can warp or debond due to thermal mismatch and inefficient cooling, leading to reduced performance and shortened lifespan.
Innovation Solution
A sputtering target design featuring a target surface component coupled to a core backing component with openings and a mechanical attachment method that minimizes heat application during joining, allowing for efficient cooling and maintaining the microstructure integrity, using techniques like ECAE and localized welding to enhance thermal and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If diffusion bonding is used to join target and backing plate, then bond strength is improved, but target microstructure is degraded due to high temperature
Solution Approach 1:
The patent changes the temperature parameter from high (diffusion bonding) to low (friction stir processing), achieving strong bonds without degrading the ultrafine grain microstructure. The FSP process operates at temperatures below 400°C, preserving the target material's microstructure while providing adequate bond strength for high-power sputtering applications.
Solution Approach 2:
The patent replaces the thermal bonding mechanism (diffusion bonding) with a mechanical bonding mechanism (friction stir processing). This mechanical approach creates metallurgical bonds through plastic deformation and material mixing without requiring high temperatures, thus avoiding microstructure degradation.
2Ease of manufacture
If monolithic target design is used, then manufacturing simplicity is improved, but mechanical stability deteriorates due to insufficient strength in thin areas
Solution Approach 1:
The patent divides the monolithic target into two separate components: a target material component and a backing plate component. These components are joined through friction stir processing, creating a composite structure that combines the advantages of both separate materials while maintaining manufacturing simplicity. The backing plate provides mechanical support to thin areas, preventing deformation during high-power sputtering.
3Device complexity
If solder bonding is used to join target and backing plate, then manufacturing cost and complexity are reduced, but bond strength becomes insufficient for high chamber power
Solution Approach 1:
The patent replaces the chemical bonding mechanism (solder bonding) with a mechanical bonding mechanism (friction stir processing). The FSP process creates strong metallurgical bonds through intensive plastic deformation and material mixing, achieving bond strengths sufficient for high-chamber-power applications while maintaining relatively simple manufacturing procedures.
4Temperature
If target thickness is reduced to improve cooling efficiency, then cooling effectiveness is improved, but mechanical strength deteriorates leading to warping
Solution Approach 1:
The patent separates the target material from the backing plate, allowing the target to be thin for efficient cooling while the backing plate provides mechanical support. The friction stir processed joint creates a strong bond that prevents warping, enabling thin target designs that maintain both cooling efficiency and mechanical strength during high-power operation.
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 design achieves reduced target deflection, improved thermal conductivity, and extended target lifespan by maintaining the ultrafine grain structure and allowing direct contact with cooling fluids, while also reducing warping and debonding risks.
Implementation Method 1
improved thermal conductivity
Implementation Method 2
the process of forming the layer—such as physical vapor deposition of a metal or other compound
Data Source
AI summary
Sputtering targets are described that comprise: a) a target surface component comprising a target material; b) a core backing component having a coupling surface, a back surface and at least one open area, wherein the coupling surface is coupled to at least part of the target surface component; and wherein at least part of the target surface component fits into at least one open area of the core backing component. In some embodiments, the target surface component, the core backing component or a combination thereof have at least one surface area feature coupled to or located in the back surface of the core backing component, the target surface component or a combination thereof, wherein the surface area feature increases the cooling effectiveness of the target surface component. Methods of forming a sputtering target are also described that comprises: a) providing a target surface component comprising a surface material; b) providing a core backing component having a coupling surface, a back surface and at least one open area; c) coupling the coupling surface to at least part of the target surface component, wherein at least part of the target surface component fits into the at least one open area of the core backing component.