Sputter-Up Magnetron Coating for Low-Particle Optical Layers
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Solution Overview
Problem
Current optical precision coating processes face challenges with high particle contamination leading to scattering, absorption, and loss mechanisms due to gravitational acceleration of particles during the 'sputter down' process, resulting in inhomogeneities and reduced long-term stability, which are critical issues for high-quality optical layers.
Innovation Solution
The method involves using cylindrical magnetron sputtering sources in a 'sputter-up' configuration, where the substrate is rotated to deposit source material against gravity, minimizing particle deposition and incorporating a plasma source for surface pretreatment and stoichiometry modification, along with precise control of process conditions to reduce particle interference and enhance layer homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sputter down process is used with gravitational acceleration, then deposition speed is improved, but particle contamination increases leading to scattering and absorption losses
Solution Approach 1:
The patent inverts the conventional sputter down process by implementing a sputter up process where the substrate is positioned above the target and material is deposited upward against gravity. This inversion prevents gravitational acceleration from increasing particle deposition energy, thereby reducing particle contamination and optical losses while maintaining deposition efficiency
2Reliability
If high layer hardness and smooth surface are achieved through compressive stresses, then layer stability is improved, but spectral shift due to temperature and humidity dependency increases
Solution Approach 1:
The patent employs plasma treatment during and after deposition to modify layer properties, achieving a balance between mechanical stability and spectral precision. The plasma treatment alters the layer structure to reduce temperature and humidity dependency while maintaining smooth surface morphology and appropriate stress states
3Manufacturing precision
If plasma treatment is applied for surface pretreatment and stoichiometry modification, then layer quality is improved, but process complexity increases
Solution Approach 1:
The patent combines plasma treatment operations with the deposition process itself, integrating surface pretreatment, deposition, and post-treatment into a single continuous vacuum cycle. This merging of operations improves layer quality through plasma modification while avoiding the need for separate process chambers or additional equipment
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 reduces particle contamination, improves layer homogeneity, and increases the long-term stability of optical coatings, resulting in higher-quality optical layers with minimized optical losses and improved precision, particularly beneficial for applications like laser engineering and UV laser applications.
Implementation Method 1
The layers are applied to the substrate from a cylindrical source material, optionally together with a reactive gas component, by magnetron sputtering
Implementation Method 2
The layers can optionally be modified in their structure or in their stoichiometric atomic composition by a plasma source within the process or within the apparatus
Data Source
AI summary
The invention relates to methods and devices for producing one or more low-particle layers on substrates in a vacuum. The layers are deposited onto the substrate from a cylindrical source material, optionally together with a reactive gas component, by means of magnetron sputtering. The layer is deposited against the force of gravity in a sputter-up method. During the method or within the device, the structure or stochiometric atomic composition of the layers can optionally be modified using a plasma source. Multiple sputtering sources with different source materials can be provided in the device such that multiple layers of different compositions can be applied on the substrate at a high speed in one process.