Rotatable Target Frame Cooling for Large Area PLD
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Solution Overview
Problem
Laser deposition techniques face challenges in heating large substrate surfaces, leading to target material evaporation, cracking, and overheating of vacuum chamber components due to increased heat radiation, which affects the composition and quality of the deposited coating.
Innovation Solution
A rotatable target frame with stationary cooling devices that can be moved into heat-exchanging contact with the target frame, combined with a heat shield and liquid cooling blocks, to effectively dissipate heat and maintain target material integrity during large area PLD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the substrate surface size is increased to coat larger areas, then the coating area is improved, but the heat radiation increases causing target material evaporation and composition change
Solution Approach 1:
The target system is segmented into multiple independent targets arranged on a rotatable target frame, allowing each target to be independently cooled while enabling coating of larger substrate areas through rotation and positioning of different targets
Solution Approach 2:
A heat shield is introduced as an intermediary component between the substrate and target material to block heat radiation from the substrate, preventing target material evaporation while allowing the substrate to be heated to required temperatures for coating
2Manufacturing precision
If the substrate is heated to 200°C - 1000°C for correct crystal structure and texture, then the coating quality is improved, but the target material cracks due to thermal expansion differences
Solution Approach 1:
The target material is pre-cooled to temperatures below room temperature before the deposition process begins, creating a thermal buffer that prevents thermal expansion cracking when the substrate is heated during coating, while still allowing the substrate to reach required temperatures for proper crystal structure
Solution Approach 2:
The heat shield serves as a thermal barrier that decouples the temperature fields of the substrate and target, allowing the substrate to be heated to 200-1000°C for proper coating crystallization while keeping the target material at safe temperatures
3Manufacturing precision
If the target material is moved or rotated for even ablation, then the coating uniformity is improved, but the cooling of the moving target becomes difficult
Solution Approach 1:
The target system is divided into multiple stationary targets mounted on a rotatable frame, where each target remains stationary and can be independently cooled, while the rotation of the entire frame allows different targets to be positioned for coating different areas of the substrate
Solution Approach 2:
Instead of rotating individual targets as in conventional systems, this invention rotates the entire target frame while keeping individual targets stationary, inverting the approach to make cooling simpler while achieving the same effect of coating large areas with uniformity
4Area of stationary object
If the substrate is heated for large area coating, then the coating area is improved, but the vacuum chamber and heat sensitive components overheat
Solution Approach 1:
The heat shield acts as a thermal intermediary that blocks heat radiation from reaching the vacuum chamber walls and sensitive components, allowing the substrate to be heated to high temperatures for large area coating while keeping the vacuum chamber at safe operating temperatures
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 solution significantly reduces target material heating, prevents cracking, and maintains the composition of the deposited coating by efficient heat management, allowing for high-temperature large area PLD with improved coating quality and reduced chamber overheating.
Implementation Method 1
at least one cooling device arranged to the base frame, which cooling device can be moved relative to the target frame to bring the cooling device in heat exchanging contact with the target frame
Implementation Method 2
The heat absorbed by the target is dissipated through the target frame to the cooling means
Implementation Method 3
a laser for generating a laser beam, which beam is directed on the target, such that a plasma plume of target material is generated
Implementation Method 4
a plasma plume of target material is generated and is deposited onto the substrate
Implementation Method 5
a heat shield is arranged between the substrate and the target for shielding the target from being heated by the heated substrate
Data Source
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AI summary
The invention relates to a laser deposition device, comprising at least one target, a substrate arranged opposite of the at least one target and a laser for generating a laser beam, which beam is directed on the target, such that a plasma plume of target material is generated and is deposited onto the substrate, further comprising a base frame, a rotatable target frame with at least two target holders arranged in the base frame and at least one cooling device arranged to the base frame, which cooling device can be moved relative to the target frame to bring the cooling device in heat exchanging contact with the target frame.