Copper Alloy Backing Plate for Magnetron Sputtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sputtering targets and backing plates face issues with film uniformity and eddy current problems during high-power magnetron sputtering, particularly due to inadequate thermal conductance and strength, leading to non-uniform film deposition and stress between the target and backing plate.
Innovation Solution
A copper or copper alloy target/backing plate assembly is developed using a low beryllium copper alloy or Cu-Ni-Si alloy with specific composition ranges for enhanced electrical conductivity and strength, diffusion bonded within a controlled temperature range to minimize warping and eddy currents, ensuring balanced anti-eddy current characteristics and film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional aluminum alloy or copper alloy backing plates with high thermal conductance are used, then the target cooling efficiency is improved, but the eddy current effects worsen leading to non-uniform film deposition
Solution Approach 1:
The invention changes the electrical conductivity parameter of the backing plate material by using copper alloys with controlled composition (Cu-0.1 to 1.0 wt% Ni, Cu-0.1 to 1.0 wt% Pd, or Cu-0.1 to 1.0 wt% Pt) to achieve specific resistance values of 2.5 to 4.5 μΩ·cm. This parameter optimization reduces eddy current effects while maintaining adequate thermal conductance for target cooling, thereby resolving the contradiction between cooling efficiency and film uniformity.
2Productivity
If high-power sputtering is employed to improve productivity, then the deposition rate increases, but the eddy current effects worsen deteriorating film uniformity
Solution Approach 1:
The invention optimizes the electrical resistance parameter of the backing plate to 2.5 to 4.5 μΩ·cm through controlled alloying, which specifically addresses eddy current generation during high-power sputtering. This enables maintenance of high deposition rates while minimizing eddy current-induced non-uniformity, thus resolving the contradiction between productivity and film quality.
3Strength
If copper alloy with high strength is used for the backing plate, then the mechanical strength increases, but the thermal conductance decreases affecting target cooling
Solution Approach 1:
The invention carefully controls the composition and quantity of alloying elements (Ni, Pd, or Pt at 0.1 to 1.0 wt%) to achieve an optimal balance between strength and thermal conductance. This controlled parameter change ensures the backing plate has sufficient mechanical strength while maintaining adequate thermal conductance for effective target cooling during high-power sputtering.
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 assembly effectively reduces warping and maintains film uniformity, providing superior anti-eddy current characteristics and thermal management, suitable for high-power sputtering applications above 30 kW.
Implementation Method 1
a material (backing plate) with high thermal conductance such as aluminum alloy, stainless steel or oxygen free copper is bonded to the back face thereof
Implementation Method 2
bonding of the target and backing plate is often conducted solidly with the diffusion bonding method
Implementation Method 3
the eddy current that occurs due to the rotation of the magnet in magnetron sputtering deteriorate the uniformity of the film
Data Source
AI summary
Provided is a copper or copper alloy target/copper alloy backing plate assembly in which the anti-eddy current characteristics and other characteristics required in a magnetron sputtering target are simultaneously pursued in a well balanced manner. This copper or copper alloy target/copper alloy backing plate assembly is used for magnetron sputtering, and the copper alloy backing plate is formed from low beryllium copper alloy or Cu—Ni—Si-based alloy. Further, with this copper or copper alloy target/copper alloy backing plate assembly, the copper alloy backing plate has electrical conductivity of 35 to 60% (IACS), and 0.2% proof stress of 400 to 850 MPa.