Coating Apparatus with Translational Motion and Distinct Precursor Regions
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Solution Overview
Problem
Existing coating methods face challenges in achieving uniformity and conformality, especially when coating large numbers or volumes of objects of varying sizes and shapes, due to mechanical screening by supporting structures, which limits the effectiveness of techniques like ALD and requires complex fluidization systems.
Innovation Solution
A method and apparatus that introduce two or more gaseous precursors into a reaction chamber, creating distinct precursor regions and allowing objects to move translationally through these regions without mechanical support, ensuring full exposure of the object's surface to the precursors, thereby enhancing uniformity and conformality of the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If objects are placed on a supporting structure for coating, then the objects can be held in position during the coating process, but mechanical screening occurs leading to non-uniform coating
Solution Approach 1:
The invention removes the supporting structure entirely from the coating process. Objects are suspended in a fluidized bed of inert particles rather than being placed on a supporting frame, eliminating the mechanical screening problem that causes non-uniform coating on the undersides and sides of objects
Solution Approach 2:
The invention introduces an intermediary medium - a fluidized bed of inert particles - to replace the supporting structure. This intermediary allows objects to be held suspended in the coating chamber without direct contact with any solid support, enabling uniform coating exposure from all directions
2Reliability
If fluidized bed is used to separate objects during coating, then coating uniformity improves, but complex electrical and mechanical constructions are required
Solution Approach 1:
The invention uses a simplified pneumatic approach where a gas stream fluidizes a bed of inert particles to suspend and disperse objects during coating. This replaces complex electrical (ultrasonic) or mechanical fluidization systems with a simpler gas-based approach that achieves the same object separation and suspension effect
Solution Approach 2:
The invention changes the state of the inert particle bed from static to fluidized by introducing a gas stream, which allows objects to be suspended and dispersed without requiring complex mechanical or electrical systems. The gas flow rate and particle properties are adjusted to achieve optimal fluidization
3Quantity of substance
If ultrasonic source is used to suspend particles, then small particles can be separated effectively, but larger or heavier objects cannot be efficiently fluidized
Solution Approach 1:
The invention changes from using ultrasonic vibration (high frequency mechanical energy) to using a gas stream (pneumatic energy) to fluidize the particle bed. This parameter change allows the system to handle a broader range of object sizes and weights, as the gas stream can be adjusted in flow rate and pressure to accommodate different object characteristics
4Reliability
If high pressure gas stream is used for fluidization, then object separation improves, but arrangement of precursor flows becomes difficult
Solution Approach 1:
The invention segments the coating chamber into distinct regions: a fluidized bed zone where objects are suspended, and separate precursor introduction zones. This segmentation allows the gas stream to be directed primarily at fluidizing the particle bed while precursors are introduced through separate pathways that are not disrupted by the high pressure gas stream, simplifying the overall flow arrangement
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
Enables cost-effective coating of large volumes and numbers of objects with high uniformity and conformality, including small particles and heavy objects, by ensuring all surface areas are exposed to the precursors, reducing the need for complex dosing systems and improving coating thickness control.
Implementation Method 1
the reactants adsorb on surfaces, e.g. on a substrate, inside the reaction chamber
Implementation Method 2
Atomic Layer Deposition (ALD) is a well known method for depositing uniform and conformal thin-films over substrates of various shapes
Implementation Method 3
causing translational, essentially mechanically unsupported and unsuspended, motion of an object inside the reaction chamber
Data Source
Figure 1
Figure 2a~2d
Figure 3a~3d
AI summary
The invention relates to a method and an apparatus for coating one or more objects (1) by exposing an object (1) to alternately repeating surface reactions of two or more gaseous precursors. The apparatus comprises a reaction chamber (2, 40), means for forming at least one distinct precursor region inside the reaction chamber, and means for causing translational, essentially mechanically unsupported and unsuspended, motion of an object (1) inside the reaction chamber, relative to the reaction chamber, for bringing the surface of the object (1) into contact with a gaseous precursor, the means for causing the translational motion comprising means for moving the object (1) essentially through the at least one distinct precursor region inside the reaction chamber.