Susceptor Trochoidal Motion for Uniform CVD Film Deposition
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Solution Overview
Problem
Variations in plasma density, pumping efficiency, and gas diffusion within the CVD equipment chamber lead to non-uniform film characteristics on substrates, even when the substrate supporting apparatus is rotated around its central axis.
Innovation Solution
A substrate supporting apparatus with a susceptor and a moving mechanism that rotates and moves the susceptor in a trochoidal trajectory within a horizontal plane, utilizing an external and internal gear system with a differential gear mechanism to ensure uniform film deposition, allowing the susceptor to be stopped at any position for optimal film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate supporting apparatus is rotated around the substrate central axis, then the film properties can be uniformed in some cases, but when the plasma density distribution peaks near the center, the film characteristics cannot be made uniform in the substrate radial direction
Solution Approach 1:
The substrate supporting apparatus employs dynamic motion patterns beyond simple rotation, including rotation combined with radial movement or oscillation, allowing the substrate to trace complex trajectories (such as trochoidal paths) that ensure all regions receive equivalent plasma exposure regardless of the plasma density distribution pattern
Solution Approach 2:
The invention transitions from one-dimensional rotation around the central axis to two-dimensional motion patterns that include both angular and radial components, enabling the substrate to access different spatial regions and achieve uniform film deposition even when plasma density varies in complex ways across the chamber
2Manufacturing precision
If the substrate supporting apparatus uses only rotation around the central axis, then the structure remains simple, but it cannot achieve uniform film characteristics when plasma density peaks are near the center
Solution Approach 1:
The moving mechanism implements dynamic motion control that combines rotation with radial displacement or oscillation, allowing the substrate to follow complex trajectories such as trochoidal paths, which ensures uniform plasma exposure and film deposition across the substrate surface
Solution Approach 2:
The system dynamically adjusts motion parameters including rotation speed, radial displacement amplitude and frequency, and trajectory shape to optimize film uniformity under different plasma density distribution conditions, transforming the motion characteristics to match process requirements
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 configuration stabilizes and uniformizes film characteristics on substrates, ensuring consistent film properties even when plasma density peaks are near the center, effectively addressing non-uniformity issues in radial directions.
Implementation Method 1
the moving mechanism includes: an external gear, tooth being placed side by side on an inner circumference thereof; and an internal gear connected to the susceptor, tooth being placed side by side on an outer circumference thereof
Data Source
AI summary
A substrate supporting apparatus includes: a susceptor configured for a substrate to be place on; and a moving mechanism that is connected to the susceptor and configured to rotate the susceptor about a central axis of the susceptor, the central axis extending in a vertical direction, wherein the moving mechanism is configured to move the susceptor further in a direction extending in an imaginary horizontal plane perpendicular to the central axis.