Electrostatic Chuck Voltage Cutoff for Stable Plasma Processing
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Solution Overview
Problem
During plasma processing, substrates experience excessive charging due to self-bias, leading to increased electrostatic force fluctuations, which can cause substrates to deviate or crack, and result in particle adhesion and frictional issues.
Innovation Solution
The plasma processing method involves stabilizing the voltage to an electrostatic chuck, then cutting off the voltage supply to bring the electrode into a floating state before plasma processing, maintaining the electrostatic force consistent with the adsorbing state to suppress excessive charging and particle attraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage is continuously supplied to the electrostatic chuck electrode during plasma processing, then the substrate remains stably adsorbed, but excessive charging occurs leading to substrate deviation and cracking
Solution Approach 1:
The patent applies periodic action by cutting off the voltage supply to the electrostatic chuck electrode at specific intervals during plasma processing. The voltage is supplied during adsorption, then cut off to allow plasma processing without excessive charging, and restored when needed. This periodic on-off cycle resolves the contradiction between maintaining stable adsorption and preventing excessive charging.
Solution Approach 2:
The patent applies preliminary action by stabilizing the voltage supply before cutting it off. The voltage is supplied first to ensure stable adsorption, then cut off before plasma processing begins to prevent excessive charging. This preliminary stabilization followed by cutoff prevents the harmful effects while maintaining the benefits.
2Object-affected harmful factors
If voltage is cut off to prevent excessive charging, then substrate charging is reduced, but substrate may deviate from the electrostatic chuck
Solution Approach 1:
The periodic action principle resolves this contradiction by timing the voltage cutoff to occur when stable adsorption is already established. The voltage is cut off only during the plasma processing phase when the substrate is already securely positioned, and restored when re-adsorption is needed. This timing ensures charging is reduced without compromising positioning stability.
Solution Approach 2:
The patent applies beforehand cushioning by ensuring the substrate is firmly adsorbed to the electrostatic chuck before cutting off the voltage. This preliminary secure attachment acts as a cushion that prevents substrate deviation even when voltage is cut off, resolving the contradiction between reducing charging and maintaining positioning stability.
3Reliability
If voltage is supplied to stabilize adsorption, then substrate remains firmly attached, but particle adhesion and friction increase
Solution Approach 1:
The periodic action principle resolves this contradiction by cutting off the voltage supply during plasma processing when particle adhesion risks are highest. The voltage is supplied only when firm attachment is needed (during adsorption phases) and cut off during processing phases to minimize particle adhesion and friction, while maintaining substrate adsorption reliability through timed restoration.
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 approach effectively reduces residual charge and particle adhesion on the substrate, preventing substrate deviation, cracking, and maintaining consistent electrostatic forces during plasma processing.
Implementation Method 1
a voltage is supplied to an electrode provided in an electrostatic chuck, thereby adsorbing a substrate onto an upper surface of the electrostatic chuck
Implementation Method 2
a predetermined processing with plasma is performed on a surface of the substrate adsorbed onto the electrostatic chuck
Data Source
AI summary
A plasma processing method includes supplying a voltage to an electrode provided in an electrostatic chuck, thereby adsorbing a substrate onto an upper surface of the electrostatic chuck; after the voltage supplied to the electrode of the electrostatic chuck is stabilized, cutting off the supply of the voltage to the electrode, thereby bringing the electrode into a floating state; and after the voltage supplied to the electrode of the electrostatic chuck is stabilized, performing a predetermined processing with plasma on a surface of the substrate adsorbed onto the electrostatic chuck.