Multi-Source Evaporation for Uniform Thin Film Deposition
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Solution Overview
Problem
Conventional deposition systems experience non-uniform thin film thickness due to edge-drop and center-drop phenomena, particularly in large-area substrates, leading to uneven deposition.
Innovation Solution
A deposition system with multiple point evaporation sources having different spraying directions, angles, and amounts to ensure uniform deposition, including a center, inner-side, and outer-side spray points, with adjustable nozzles and heaters to control the deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single point evaporation source is used for deposition, then the device complexity is low, but the thin film thickness uniformity deteriorates due to edge-drop and center-drop phenomena
Solution Approach 1:
The single evaporation source is divided into multiple point evaporation sources (first, second, third, and fourth point evaporation sources) positioned at different locations around the substrate. Each source deposits material with a specific spatial distribution pattern, and their combined effect achieves uniform thickness across the entire substrate surface, eliminating edge-drop and center-drop phenomena.
Solution Approach 2:
Each point evaporation source is assigned a specific functional role based on its position: some sources are optimized for depositing material uniformly at the substrate center, while others are optimized for the edge regions. This local specialization allows each source to address specific deposition challenges in its designated zone, achieving overall uniformity.
2Manufacturing precision
If multiple point evaporation sources with different spraying directions are used, then the thin film thickness uniformity is improved, but the device complexity increases
Solution Approach 1:
The point evaporation sources are configured with asymmetric spraying directions relative to the substrate normal. Instead of all sources spraying perpendicular to the substrate, they are angled at different orientations to target specific regions (center vs. edges). This asymmetric configuration allows material to be directed precisely where needed, compensating for natural deposition non-uniformities.
Solution Approach 2:
The deposition system transitions from a single-axis (vertical) deposition approach to a multi-dimensional arrangement where evaporation sources are positioned and angled in three-dimensional space. By utilizing spatial coordinates (x, y, z positions and angular orientations), the system achieves comprehensive coverage and uniform deposition across the substrate surface.
3Productivity
If the substrate area is increased, then the productivity is improved, but the thin film thickness uniformity deteriorates due to edge-drop phenomenon
Solution Approach 1:
The substrate surface is effectively segmented into multiple deposition zones, each served by a dedicated point evaporation source. As substrate area increases, additional sources are added to cover the expanded surface, maintaining uniform deposition across the entire area without the edge-drop phenomenon that plagues single-source systems.
Solution Approach 2:
The multi-source evaporation system is designed to handle various substrate sizes and shapes universally. By configuring multiple point sources with adjustable positions and spraying directions, the system can adapt to different substrate areas while maintaining uniform thickness, making it applicable to both small and large substrates.
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
The system achieves significantly improved thin film thickness uniformity, reducing management and repair costs by minimizing non-uniformity and adapting to varying substrate shapes and sizes.
Implementation Method 1
an evaporation material is accommodated in a cylindrical crucible, the crucible is heated, and the evaporation material is sprayed toward a front surface of a substrate
Implementation Method 2
a deposition method using a linear evaporation source and a deposition method using a point evaporation source are mainly used
Data Source
AI summary
The present invention relates to a deposition system. According to an embodiment of the present invention, a deposition system including a plurality of evaporation sources includes a substrate and a plurality of point evaporation sources that spray a deposition material onto the substrate, and at least two of the plurality of point evaporation sources have different spraying directions.