Thermal Evaporation Substrate Shielding for Window Protection
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Solution Overview
Problem
In thermal evaporation systems, the chamber window is often exposed to evaporated or sublimated source material, leading to premature degradation and requiring frequent replacement, and achieving optimal coating on large substrates is challenging due to spatial competition between the chamber window and the substrate.
Innovation Solution
The method involves arranging a transparent substrate between the chamber window and the source within the reaction chamber, allowing electromagnetic radiation to shine through the substrate and illuminate the source, thereby preventing deposition on the chamber window and optimizing the distance between the source and the substrate, while using focused radiation beams and reflected radiation for uniform coating and annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the chamber window is positioned to allow direct line of sight for electromagnetic radiation to reach the source, then the radiation can effectively heat the source material for evaporation/sublimation, but the chamber window becomes exposed to evaporated source material leading to premature degradation and frequent replacement
Solution Approach 1:
The substrate is introduced as an intermediary element positioned between the chamber window and the source. It serves dual functions: allowing electromagnetic radiation to pass through to heat the source while simultaneously blocking evaporated source material from reaching and degrading the chamber window. This mediator resolves the contradiction by decoupling the radiation transmission function from the material deposition exposure.
2Productivity
If the substrate is positioned close to the source to optimize material utilization and coating efficiency, then the coating process becomes more productive, but the chamber window and substrate compete for space making optimal positioning difficult
Solution Approach 1:
The system transitions from a traditional side-illumination geometry to a configuration where the substrate is positioned in the direct path between the chamber window and source. This dimensional reorganization allows the substrate to serve as both the coating target and the protective element, eliminating spatial competition and enabling optimized positioning for both productivity and window protection.
3Area of stationary object
If an almost grazing impingement angle of electromagnetic radiation onto the source is used to accommodate large substrates, then the chamber window can be positioned higher, but the operation becomes unstable when the source surface deviates from horizontal
Solution Approach 1:
Instead of tilting the radiation beam at a grazing angle to accommodate the substrate, the invention inverts the approach by positioning the substrate perpendicular to the radiation path. The substrate is placed in the direct line of sight between the chamber window and source, allowing normal (non-grazing) radiation impingement while still accommodating large substrate areas. This inversion stabilizes operation by eliminating sensitivity to source surface orientation.
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 prolongs the service life of the evaporation system by preventing source material deposition on the chamber window and enables efficient, uniform coating of large substrates with improved homogeneity and reduced risk of substrate damage.
Implementation Method 1
coating a coating region on a front surface of a substrate with a source material thermally evaporated and/or sublimated from a source by electromagnetic radiation
Implementation Method 2
coating a coating region on a front surface of a substrate with a source material thermally evaporated and/or sublimated from a source by electromagnetic radiation
Implementation Method 3
illuminate the source with the one or more incident radiation beams through the substrate during the coating process
Data Source
AI summary
The present invention is related to a method of coating a coating region (58) on a front surface (56) of a substrate (50) with a source material (40) thermally evaporated and/or sublimated from a source (30) by electromagnetic radiation (80). Further, the present invention is related to an apparatus (100) for a thermal evaporation system (200) for coating a coating region (58) on a front surface (56) of a substrate (50) with a source material (40) thermally evaporated and/or sublimated by electromagnetic radiation (80) from a source (30).