Tubular Sputtering Cathode With Inward-Facing Rotary Targets
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Solution Overview
Problem
Conventional sputtering devices face challenges in achieving high film forming speeds with low bombardment and efficient target usage, particularly when forming thin films on large-area substrates, and are prone to foreign matter deposition during film formation.
Innovation Solution
A sputtering cathode with a tubular target having inward-facing erosion surfaces and a magnetic circuit, featuring rotary targets and a curved surface design to enhance plasma density and prevent foreign matter deposition, along with a parallel arrangement of cathodes to increase film forming speed and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If facing-target sputtering device is used, then reflected neutral process-gas particles can be prevented from bombarding the substrate, but plasma density between targets is low and film forming speed is insufficient
Solution Approach 1:
The patent inverts the conventional facing-target configuration by using inward-facing erosion surfaces that face each other, creating a plasma-rich environment between the targets while maintaining the benefit of reduced substrate bombardment. This inversion allows high plasma density to be achieved in the sputtering region without directly exposing the substrate to high-energy particle bombardment.
Solution Approach 2:
The patent introduces a tubular target geometry with inward-facing surfaces, adding a dimensional aspect to the target configuration. This three-dimensional structure creates a plasma confinement region between the inward-facing surfaces, increasing plasma density in a specific spatial zone while maintaining controlled particle trajectories away from the substrate.
2Productivity
If tubular target with inward-facing erosion surfaces is used, then film forming speed increases, but target usage efficiency is insufficient
Solution Approach 1:
The patent employs rotary targets that rotate during sputtering operation. This dynamic element ensures uniform erosion across the entire target surface, preventing localized depletion and maximizing target usage efficiency. The rotation continuously presents fresh target material to the plasma, maintaining consistent sputtering rates throughout the target lifespan.
Solution Approach 2:
The patent combines multiple functional elements into a unified tubular target structure: the inward-facing erosion surfaces for plasma confinement, the rotary mechanism for uniform erosion, and the tubular geometry for enhanced plasma density. This integration achieves both high film forming speed and improved target usage efficiency simultaneously.
3Area of stationary object
If stationary sputtering is performed on large-area substrates, then film formation can be performed, but foreign matter deposition occurs on the target
Solution Approach 1:
The rotating target design creates dynamic motion that prevents foreign matter from settling and depositing on the target surface. The continuous rotation dislodges any particulate matter that may form during sputtering, preventing accumulation and contamination. This dynamic approach enables stable operation for large-area substrate processing without foreign matter deposition issues.
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 solution enables high-speed film formation with low damage to the substrate, high target usage efficiency, and stable operation by increasing plasma density and preventing foreign matter deposition, allowing for efficient film formation on large-area substrates.
Implementation Method 1
a magnetic circuit being provided along the sputtering target
Implementation Method 2
discharge is performed, whereby film formation is performed by sputtering the targets
Data Source
AI summary
The sputtering cathode has a tubular shape having a pair of long sides facing each other in cross-sectional shape, has a sputtering target whose erosion surface faces inward, and a magnetic circuit is provided along the sputtering target. The pair of long sides are constituted by rotary targets each having a cylindrical shape. The rotary target is internally provided with a magnetic circuit and configured to allow the flow of cooling water. The magnetic circuit is provided parallel to the central axis of the rotary target and has a rectangular cross-sectional shape having a long side perpendicular to the radial direction of the rotary target.