Rotatable Target Magnet Positioning for Uniform Sputtering
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Solution Overview
Problem
Existing sputtering methods for coating substrates struggle to achieve uniformity in layer thickness, crystal structure, and stress across the entire substrate, which is crucial for applications like display production where non-uniform layers can lead to inconsistent performance.
Innovation Solution
A method involving a rotatable target with asymmetrically positioned magnet assemblies, where the magnets are moved to specific angles and voltages are varied over time to optimize the deposition process, ensuring uniformity by adjusting the plasma generation area and sputtering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnet assembly is constantly moved with constant angular velocity during sputtering, then the homogeneity of the deposited layer is improved, but the homogeneity can still be improved further
Solution Approach 1:
The magnet assembly is positioned at discrete angular positions for predetermined time intervals rather than moving continuously. The method involves positioning the magnet assembly at a first angular position for a first time interval, then positioning it at a second angular position for a second time interval, creating a periodic deposition pattern that builds up uniform layer homogeneity over multiple cycles
Solution Approach 2:
The magnet assembly is made movable within the rotatable target, allowing dynamic adjustment of its angular position. The system transitions from a static magnet configuration to a dynamic one where the magnet can be repositioned to different angular locations during the sputtering process to control plasma generation areas and achieve uniform deposition
2Manufacturing precision
If the magnet assembly is positioned asymmetrically with respect to the substrate-target plane, then the plasma generation area is optimized for uniformity, but the deposition rate may be reduced
Solution Approach 1:
The magnet assembly is positioned at optimal asymmetric angular positions before the sputtering process begins or at the start of each deposition cycle. By pre-positioning the magnet at angles that optimize plasma generation area and material flux distribution, the system ensures uniform deposition from the beginning of each time interval without requiring real-time adjustments during deposition
Solution Approach 2:
The angular position parameter of the magnet assembly is changed to asymmetric positions relative to the substrate-target plane. This parameter change optimizes the plasma generation area and material flux distribution patterns, creating more uniform deposition across the substrate surface by controlling where ions and sputtered atoms are generated and directed
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 approach significantly enhances the homogeneity of the deposited layer, achieving uniformity in thickness, crystal structure, and stress, thereby improving the consistency and performance of coated substrates, particularly in large-area applications like displays and solar cells.
Implementation Method 1
a magnet assembly positioned within the rotatable target
Implementation Method 2
When the gas ions hit the outer surface of the target, their momentum is transferred to the atoms of the material so that some of them can gain sufficient energy to overcome their bonding energy in order to escape from the target surface and to deposit on the substrate
Implementation Method 3
Sputtering is a vacuum coating process used to deposit thin films of various materials onto the surface of a substrate
Implementation Method 4
ions of an inert gas or reactive gas that are accelerated by a high voltage
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~6
AI summary
A method is provided for coating a substrate (100) with a cathode assembly (10) having a rotatable target (20). The rotatable target has at least one magnet assembly (25) positioned there within. The method includes positioning the magnet assembly at a first position so that it is asymmetrically aligned with respect to a plane (22) perpendicularly extending from the substrate (100) to the axis (21) of the rotatable target for a predetermined first time interval; positioning the magnet assembly at a second position that is asymmetrically aligned with respect to said plane (22) for a predetermined second time interval; and providing a voltage to the rotatable target that is varied over time during coating. Further, a coater is provided that includes a cathode assembly with a rotatable curved target; and two magnet assemblies positioned within the rotatable curved target wherein the distance between the two magnet assemblies can be varied.