DUV Optical Coating for Non-Rotational Thickness Profiles
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Solution Overview
Problem
Existing methods for depositing reflective or anti-reflective coatings in the deep ultraviolet (DUV) wavelength range face challenges in achieving non-rotationally symmetric layer thickness profiles, particularly for substrates with non-symmetric surfaces, due to limitations in controlling coating rates and rotation speeds, leading to inefficiencies and high technical complexity.
Innovation Solution
The method involves varying the coating rate and/or rotation speed of the substrate during movement along a predetermined path, using techniques such as pulsed or RF sputtering, and employing a cover to control the coating rate, allowing for the production of arbitrary non-rotationally symmetric thickness profiles by adjusting parameters like DC voltage and evaporation rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional planetary movement with constant rotation speed is used, then coating process is simple, but non-rotationally symmetric layer thickness profiles cannot be achieved
Solution Approach 1:
The patent applies dynamics by making the rotation speed of the substrate variable during the coating process. The substrate rotates at different speeds in different angular positions, allowing precise control of layer thickness distribution. This dynamic adjustment enables non-rotationally symmetric profiles without requiring complex mask structures, resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The patent changes the rotation speed parameter of the substrate during coating based on angular position. By varying this parameter dynamically, the system achieves precise control over layer thickness profiles, including non-rotationally symmetric patterns. This parameter change approach allows flexible profile control without adding mechanical complexity to the coating apparatus.
2Manufacturing precision
If covering elements are used to control layer thickness, then radial symmetry is achieved, but non-rotationally symmetric profiles require complex mask designs
Solution Approach 1:
The patent replaces the mechanical mask system with a dynamic control system. Instead of using physical masks or covering elements to define layer thickness patterns, the invention uses variable rotation speed control of the substrate. This substitution eliminates the need for complex mask designs while achieving precise non-rotationally symmetric profiles, resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The patent introduces dynamic control of substrate rotation speed to replace static mask structures. By adjusting rotation speed as a function of angular position, the system achieves flexible layer thickness control without requiring physical masks. This dynamic approach simplifies the overall system while maintaining high manufacturing precision for complex profiles.
3Adaptability or versatility
If variable substrate speed is implemented, then arbitrary thickness profiles are achieved, but structural complexity increases considerably
Solution Approach 1:
The patent makes the substrate rotation system multi-functional by enabling it to perform both the basic rotation required for uniform coating and the variable speed control needed for complex profiles. This universal substrate drive mechanism can accommodate different profile requirements through software control rather than mechanical modification, achieving high adaptability without proportional increases in structural complexity.
Solution Approach 2:
The patent replaces complex mechanical variable speed mechanisms with electronic/software-based control. The substrate rotation speed is adjusted through control signals rather than mechanical transmissions, allowing arbitrary thickness profiles to be generated through programmable control. This substitution dramatically reduces structural complexity while maintaining full profile design flexibility.
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 enables the creation of precise, non-rotationally symmetric layer thickness profiles, reducing the need for complex mask designs and trial-and-error methods, thereby improving the optical performance and reducing manufacturing costs and time.
Implementation Method 1
converting a coating material into the gas phase using a coating source
Implementation Method 2
using techniques such as pulsed or RF sputtering
Implementation Method 3
moving the substrate relative to the coating source along a predetermined movement path, wherein the substrate rotates around a spin axis during the movement along the movement path
Data Source
AI summary
A method for depositing a layer (2) of a coating which is reflective or anti-reflective to DUV radiation onto a surface (3a) of a substrate (3) for a DUV optical element includes: transferring a coating material (M) into the gas phase in a coating source (4′), moving the substrate relative to the coating source along a predetermined movement path (5), and varying a coating rate (RB) and/or a rotation speed (ω(t)) of a spin axis (7) of the substrate during the movement along the movement path. A covering element (6) is arranged between the coating source (4′) and the surface and covers the surface at least partially during the movement of the substrate. Also disclosed is an optical element for the DUV wavelength range, with a substrate and a reflective or anti-reflective coating (B) applied to the substrate, having at least one layer deposited by the disclosed method.