Gas-Levitated Substrate Rotor for Low-Particle Wafer Rotation
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Solution Overview
Problem
Conventional substrate rotation systems, such as those using ball bearings and magnetic levitation, suffer from particle generation, high costs, and vibration issues, which affect temperature uniformity and wafer quality during processing.
Innovation Solution
A magnetically-coupled, gas-levitated assembly that includes a rotor with embedded magnets, gas bearings for levitation, and a stator generating a rotating magnetic field to rotate substrates without physical contact, reducing vibrations and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ball bearing rotation systems are used, then substrate rotation is achieved, but particle generation occurs due to contact between ball bearings and races
Solution Approach 1:
The patent replaces the mechanical ball bearing system with a magnetic field-based rotation system. Magnets embedded in the substrate interact with a rotating magnetic field generated by coils, eliminating mechanical contact between moving parts and thus preventing particle generation from bearing contact.
Solution Approach 2:
The patent introduces gas bearings that use a film of gas (typically nitrogen or air) to levitate the substrate, replacing mechanical contact with fluid-based support. This eliminates particle generation from solid-to-solid contact while maintaining rotation capability.
2Reliability
If conventional magnetic levitation systems are used, then substrate rotation is achieved, but high cost and periodic tuning are required
Solution Approach 1:
The patent uses conventional, inexpensive materials such as embedded magnets in the substrate and standard electromagnetic coils for the rotating magnetic field, replacing expensive specialized maglev components. The system uses readily available components that do not require expensive periodic tuning.
3Reliability
If ball bearing rotation systems are used, then substrate rotation is achieved, but vibrations are generated that shed particles from chamber walls
Solution Approach 1:
The patent eliminates the mechanical ball bearing system that generates vibrations through friction and contact. The magnetic field-based rotation and gas bearing levitation create smooth, vibration-free operation, preventing particles from being shaken loose from chamber walls.
4Reliability
If complicated bearing structures are used, then substrate rotation is achieved, but large surface area is available for absorption of undesirable gases and vapors
Solution Approach 1:
The patent removes the complicated bearing structure entirely, replacing it with a simplified system using embedded magnets and gas bearings. This extraction of the complex bearing mechanism eliminates the large surface area that would otherwise be available for absorbing undesirable gases and vapors.
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 solution provides low-cost, vibration-reduced, and circumferentially uniform substrate rotation, enhancing processing quality by minimizing particle generation and maintaining chamber integrity.
Implementation Method 1
a plurality of gas bearings positioned to levitate the levitatable rotor
Implementation Method 2
a stator magnetically coupled to the levitatable rotor, the stator for producing a rotating magnetic field
Implementation Method 3
a levitatable rotor comprising a plurality of magnets embedded therein
Data Source
AI summary
Embodiments of the present disclosure generally relate to apparatus for substrate processing, and more specifically to apparatus for rotating substrates and to uses thereof. In an embodiment, an apparatus for rotating a substrate is provided. The apparatus includes a levitatable rotor comprising a plurality of magnets embedded therein, a plurality of gas bearings positioned to levitate the levitatable rotor, and a stator magnetically coupled to the levitatable rotor, the stator for producing a rotating magnetic field. Apparatus for processing a substrate with the apparatus for rotating substrates as well as methods of use are also described.