Electrostatic Chuck Voltage Compensation for Stable Plasma Etching
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Solution Overview
Problem
The voltage drop inside the plasma sheath affects the electrostatic chuck's chucking force, leading to unstable substrate mounting and reduced processing accuracy during semiconductor manufacturing.
Innovation Solution
A compensation unit calculates a compensation value for the second voltage based on sensor measurements to compensate for the loss of chucking force due to voltage drop, using a DC bias value approximation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma is generated in the processing space, then etching process is enabled, but voltage drop inside the sheath causes loss of chucking force
Solution Approach 1:
The patent applies feedback by measuring the actual voltage inside the plasma sheath using a sensor and using this measurement to dynamically adjust the electrostatic chuck voltage. The control unit continuously monitors the sheath voltage and modifies the chuck voltage in real-time to compensate for voltage drop, thereby maintaining stable substrate mounting during the etching process.
Solution Approach 2:
The patent changes the voltage parameter of the electrostatic chuck dynamically based on plasma conditions. By adjusting the chuck voltage according to the measured sheath voltage, the system adapts to varying plasma conditions and maintains adequate chucking force throughout the etching process.
2Reliability
If electrostatic chuck voltage is increased to maintain chucking force, then substrate mounting stability is improved, but processing accuracy may be reduced due to voltage drop
Solution Approach 1:
The control unit uses real-time feedback from the voltage sensor to precisely adjust the electrostatic chuck voltage, applying only the necessary compensation rather than excessive voltage. This precise control maintains substrate stability without introducing errors that could affect processing accuracy.
Solution Approach 2:
The system dynamically adjusts the electrostatic chuck voltage based on real-time plasma conditions rather than using a fixed high voltage. This dynamic adjustment allows the system to maintain adequate chucking force while avoiding over-voltage conditions that could compromise processing precision.
3Reliability
If sensor measurement is implemented to measure sheath voltage, then compensation for chucking force loss is enabled, but device complexity increases
Solution Approach 1:
The patent introduces a voltage sensor as an intermediary element that measures the sheath voltage and provides this information to the control unit. This sensor acts as a mediator between the plasma environment and the control system, enabling compensation without requiring complex direct intervention in the plasma generation process.
Solution Approach 2:
The feedback mechanism using a simple voltage sensor and control unit provides an elegant solution that maintains chucking force stability without requiring complex mechanical or structural modifications to the system.
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
Prevents substrate position changes and improves processing accuracy by compensating for chucking force loss in real-time.
Implementation Method 1
an electrostatic chuck supporting a substrate within the chamber
Implementation Method 2
a plasma generating unit generating plasma in the processing space
Data Source
AI summary
An apparatus and method of processing a substrate are provided. The apparatus for processing a substrate includes a chamber having a processing space therein, an electrostatic chuck supporting a substrate within the chamber, a plasma generating unit generating plasma in the processing space, a first voltage application unit applying a first voltage to the electrostatic chuck, a second voltage application unit applying a second voltage to the electrostatic chuck, and a compensation unit calculating a compensation value for the second voltage based on a measurement value of a sensor disposed in the first voltage application unit, and compensating for loss of chucking force generated in the electrostatic chuck based on the compensation value for the second voltage.