Cathode Device with Parallel Link Mechanism for Uniform Erosion
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Solution Overview
Problem
Existing cathode devices with rotating magnetic circuits suffer from uneven erosion portion formation on the target surface due to a constant horizontal magnetic field, leading to reduced target life and increased sputtering inefficiency.
Innovation Solution
A cathode device with a rotation plate, linear motion parallel link mechanism, and a controller that allows the magnetic circuit to move at six degrees of freedom, reducing uneven erosion formation by dynamically changing the position and orientation of the magnetic field, thereby minimizing its interference and extending the target's life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the magnetic circuit is rotated to distribute erosion, then target life is extended, but uneven erosion formation occurs because the horizontal magnetic field stays on portions closer to the rotational center
Solution Approach 1:
The magnetic circuit is made dynamically movable through a parallel link mechanism that enables six-degree-of-freedom motion (three translational and three rotational degrees). This allows the magnetic circuit to change its position and orientation continuously, preventing the horizontal magnetic field from concentrating on specific portions of the target surface, thereby achieving uniform erosion distribution while extending target life
Solution Approach 2:
The invention transitions from simple rotational motion (one-dimensional) to six-degree-of-freedom motion (three-dimensional spatial control). By adding translational movements along X, Y, and Z axes plus rotational movements around three axes, the magnetic circuit can access multiple positions and orientations, distributing the erosion uniformly across the entire target surface rather than concentrating it near the rotational center
2Productivity
If the horizontal magnetic field strength is kept constant during rotation, then sputtering efficiency is maintained, but uneven erosion formation becomes more noticeable
Solution Approach 1:
The magnetic circuit is made dynamically movable through a parallel link mechanism that enables six-degree-of-freedom motion (three translational and three rotational degrees). This allows the magnetic circuit to change its position and orientation continuously, preventing the horizontal magnetic field from concentrating on specific portions of the target surface, thereby achieving uniform erosion distribution while extending target life
Solution Approach 2:
The magnetic circuit structure is designed to perform multiple functions: it can rotate around the target, translate along three axes, and incline at various angles. This multi-functional capability allows the system to maintain constant magnetic field strength while achieving uniform erosion distribution through diverse motion patterns, resolving the contradiction between maintaining sputtering efficiency and achieving uniform erosion
3Manufacturing precision
If the magnetic circuit is made movable to change position, then erosion uniformity is improved, but device complexity increases due to additional mechanisms
Solution Approach 1:
The magnetic circuit is made dynamically movable through a parallel link mechanism that enables six-degree-of-freedom motion (three translational and three rotational degrees). This allows the magnetic circuit to change its position and orientation continuously, preventing the horizontal magnetic field from concentrating on specific portions of the target surface, thereby achieving uniform erosion distribution while extending target life
Solution Approach 2:
A parallel link mechanism serves as an intermediary structure between the fixed base and the magnetic circuit. This mechanism, consisting of multiple links and actuators, provides six-degree-of-freedom motion control while maintaining structural integrity and positioning precision. The parallel link structure distributes mechanical loads across multiple components, reducing individual component complexity while achieving the desired motion capabilities for uniform erosion distribution
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 dynamic positioning and orientation of the magnetic circuit enhance sputtering efficiency by uniformly distributing the erosion, reducing target wear, and improving the reproducibility of the magnetic field's position, thus extending the target's life and maintaining sputtering performance.
Implementation Method 1
A magnetic circuit included in a cathode device is disposed at a side of a target opposite to a film formation space and forms a leakage magnetic field in the film formation space. The leakage magnetic field includes a horizontal magnetic field extending along the surface of the target.
Implementation Method 2
The linear motion mechanisms move the proximal ends of adjacent two of the links in one direction when receiving power from respective linear actuators.
Implementation Method 3
a rotation mechanism including a rotation shaft that rotates the rotation plate when receiving power from a motor
Implementation Method 4
The horizontal magnetic field increases the density of plasma in the vicinity of the surface of the target to improve the sputtering efficiency. The position where an erosion portion is formed is limited to a portion of the surface of the target at a position opposed to the horizontal magnetic field.
Data Source
AI summary
A cathode device includes a rotation plate to which a magnetic circuit is fixed, a rotation mechanism including a rotation shaft that rotates the rotation plate when receiving power from a motor, and a linear motion parallel link mechanism. The parallel link mechanism includes an end effector, six links each having a distal end and a proximal end, and three linear motion mechanisms. The end effector rotationally supports the rotation shaft, the distal ends of the links are connected to the end effector, the links radially extend from the end effector, and the linear motion mechanisms move the proximal ends of adjacent two of the links in one direction when receiving power from respective linear actuators. A controller controls a change in position of the rotation shaft performed by a cooperative operation of the linear actuators, and controls rotation of the rotation shaft operated by the motor.