Magnetron Sputtering Control Electrodes for Film Uniformity
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Solution Overview
Problem
Conventional magnetron sputtering techniques face issues with uneven film thickness distribution due to differences in impedance among magnets over time, leading to thinner films at the center compared to the edges of the substrate.
Innovation Solution
A magnetron sputtering apparatus with control electrodes that can independently control potentials in the discharge space, where the potential of control electrodes in the center region is set higher than in lateral regions, adjusting impedance and plasma density to achieve even film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional magnetron sputtering is performed with fixed magnet arrangement, then initial film formation is efficient, but film thickness uniformity deteriorates over time due to target digging and impedance differences
Solution Approach 1:
The patent applies dynamics by making the control electrodes adjustable in position and potential. The control electrodes can be moved radially inward or outward, and their potentials can be independently adjusted, allowing the system to adapt to changing target conditions over time and maintain uniform film thickness throughout the sputtering process
Solution Approach 2:
The patent changes physical parameters by adjusting the potentials of control electrodes and their radial positions. By varying these parameters, the plasma density distribution can be modified to compensate for target digging effects, thereby maintaining film thickness uniformity over extended periods
2Productivity
If target is used for long period, then productivity is maintained, but impedance differences among magnets increase causing plasma distribution unevenness
Solution Approach 1:
The patent implements feedback by using control electrodes that can sense and respond to impedance differences among magnets. By independently adjusting the potentials of control electrodes corresponding to individual magnets, the system compensates for plasma distribution unevenness that develops during prolonged operation
Solution Approach 2:
The patent modifies operational parameters by adjusting the potentials and positions of control electrodes based on the actual state of the target and plasma distribution, enabling continuous adaptation during long-term operation to maintain reliable plasma uniformity
3Manufacturing precision
If control electrodes are added to adjust plasma density, then film thickness uniformity is improved, but device complexity increases
Solution Approach 1:
The control electrodes serve multiple functions: they control plasma density distribution, adjust for impedance differences among magnets, and compensate for target digging effects. This multi-functionality reduces the need for separate correction mechanisms, thereby limiting the increase in device complexity
Solution Approach 2:
The patent uses parameter changes of existing components (control electrode potentials and positions) to achieve film thickness uniformity, rather than introducing entirely new complex subsystems. This approach improves manufacturing precision while relatively limiting the increase in device complexity
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 ensures even film thickness distribution over long-term target use by adjusting plasma density and film formation rate, enhancing film uniformity and formation efficiency.
Implementation Method 1
a power source that supplies power to the cathode part
Implementation Method 2
a magnetron sputtering method for generating a magnetron discharge in a vacuum
Implementation Method 3
a plurality of rod-shaped magnets 112 is arranged on the backside
Implementation Method 4
performing sputtering
Data Source
AI summary
The present invention is to provide a magnetron sputtering technique for forming a film having an even film thickness distribution for a long period of time. A magnetron sputtering apparatus of the present invention includes a vacuum chamber, a cathode part provided in the vacuum chamber, the cathode part holding a target on the front side thereof and having a backing plate to hold a plurality of magnets on the backside thereof, and a direct-current power source that supplies direct-current power to the cathode part. A plurality of control electrodes, which independently controls potentials, is provided in a discharge space on the side of the target with respect to the backing plate.