Multi-Phase Electrostatic Chuck Layout for Uniform Wafer Holding
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Solution Overview
Problem
Existing stage designs for substrate processing in plasma processing apparatuses face challenges in maintaining consistent and uniform electrostatic attraction forces across the substrate, leading to irregularities in processing outcomes.
Innovation Solution
The stage incorporates a base with an electrostatic chuck featuring N electrodes, where N is two or more, and a power supply that applies N-phase AC voltages of different phases to these electrodes. The electrodes are arranged in a spiral pattern with equal pitches and constant lengths, ensuring rotational symmetry and consistent attraction forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-phase AC voltage is applied to the electrode, then the structure is simple, but the attraction force becomes irregular and non-uniform across the substrate
Solution Approach 1:
The electrode is divided into N segments (electrode sections) arranged around the substrate, with each segment independently controlled by a separate power supply. This segmentation allows different phase angles to be applied to different segments, creating a balanced rotating electric field that produces uniform attraction force across the substrate surface.
Solution Approach 2:
N-phase AC voltages with different phase angles are applied periodically to the N electrode sections, creating a time-varying rotating electric field. The periodic switching of phases ensures that the attraction force remains constant on average while eliminating irregularities that would occur with single-phase operation.
2Manufacturing precision
If N-phase AC voltages with different phases are applied to N electrodes, then the attraction force becomes constant and uniform, but the device complexity increases
Solution Approach 1:
Multiple power supplies are merged into a coordinated system where each power supply applies AC voltage with a specific phase angle. The power supplies work together as an integrated system, with their outputs combined through the electrode structure to create a unified rotating electric field that achieves uniform attraction force.
Solution Approach 2:
The phase angles of the AC voltages applied to different electrode sections are specifically adjusted to create a balanced rotating field. By changing the phase parameters (setting each phase angle to 360°/N intervals), the system transforms from producing irregular attraction forces to producing constant and uniform attraction force across the substrate.
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 ensures a constant and uniform attraction force across the substrate, reducing irregularities in plasma processing and enhancing the reliability and consistency of substrate processing outcomes.
Implementation Method 1
an electrostatic chuck featuring N electrodes, where N is two or more... a power supply that applies N-phase AC voltages of different phases to these electrodes... ensures a constant and uniform attraction force across the substrate
Data Source
AI summary
A stage includes a base and an electrostatic chuck provided on the base and including N electrodes in the electrostatic chuck, where N is an integer greater than or equal to two. The stage a power supply configured to apply voltages of different N-phases to the respective N electrodes. Each of the voltages has a positive level and a negative level that periodically alternate. A center line of an electrode gap provided between adjacent electrodes is represented by x=x=r·cos(θ+2π(n−1)/N) and y=r·sin(θ+2π(n−1)/N).