Electrostatic Chuck Bias Circuit for Stable Plasma Potential
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma processing apparatuses face challenges in controlling the potential fluctuations of the substrate support when using a DC pulse power supply, leading to process shifts due to fluctuations in impedance and output current.
Innovation Solution
The apparatus incorporates a substrate support with an electrostatic chuck and bias electrodes, featuring a first and second region, and an impedance adjustment mechanism with a variable capacitor to stabilize the potential of the substrate support by adjusting the capacitance of the variable capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a DC pulse power supply is used to supply bias to the substrate support, then the ion energy and angle control is improved, but the potential of the substrate support fluctuates due to impedance changes, causing process shifts
Solution Approach 1:
The system employs a feedback mechanism where the impedance adjustment mechanism continuously monitors and adjusts the capacitance value in response to potential fluctuations of the substrate support. This closed-loop control stabilizes the substrate support potential while maintaining the benefits of DC pulse power supply for ion energy control.
Solution Approach 2:
The invention dynamically changes the capacitance parameter of the impedance adjustment mechanism to compensate for impedance variations in the electrical path. By adjusting the capacitance value, the system maintains stable substrate support potential despite changes in electrical conditions during plasma processing.
2Adaptability or versatility
If the electrical path includes multiple components (base, electrostatic chuck, bias electrodes), then the substrate support functionality is improved, but the impedance of the electrical path fluctuates, causing output current variations
Solution Approach 1:
The impedance adjustment mechanism acts as an intermediary element in the electrical path, mediating between the power supply and the substrate support components. It compensates for impedance variations introduced by the base, electrostatic chuck, and bias electrodes, thereby stabilizing the output current.
Solution Approach 2:
The system introduces dynamic adjustment capability through the variable capacitor in the impedance adjustment mechanism. This allows the electrical characteristics of the path to be adapted in real-time, compensating for variations caused by the multiple functional components and maintaining reliable operation.
3Adaptability or versatility
If the substrate support includes multiple regions (first region for substrate, second region for edge ring), then the processing versatility is improved, but the impedance control complexity increases
Solution Approach 1:
The substrate support is segmented into distinct functional regions (first region for substrate, second region for edge ring), each with its own bias electrode. The impedance adjustment mechanism provides centralized control that manages the complexity of multiple regions through a unified capacitance adjustment approach.
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 the potential of the substrate support, preventing process shifts and enabling precise control of ion energy and angle, thereby enhancing processing consistency.
Implementation Method 1
an impedance adjustment mechanism with a variable capacitor to stabilize the potential of the substrate support by adjusting the capacitance of the variable capacitor
Implementation Method 2
a substrate support with an electrostatic chuck and bias electrodes
Data Source
AI summary
A plasma processing apparatus includes a chamber, a bias power supply to supply a pulsed bias DC signal, a substrate support to support a substrate and an edge ring in the chamber, and an electrical path. The substrate support has an electrostatic chuck that includes a first region to hold the substrate and a second region provided around the first region and to hold the edge ring, and is formed from a dielectric, a first bias electrode inside the first region, a second bias electrode inside the second region, a base to support the electrostatic chuck, and a first impedance adjustment mechanism to have a first variable capacitor connected between the second bias electrode and the base.