Electrostatic Chuck Switch Verification for Stable Plasma Processing
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Solution Overview
Problem
When a switch in the wiring between an electrode and a power supply in a plasma processing apparatus is out of order, it fails to apply the desired voltage to the electrode, leading to inadequate electrostatic force, substrate movement during processing, and reduced processing accuracy.
Innovation Solution
A plasma processing apparatus with an electrostatic chuck, first and second switches, and a control unit that confirms the switches are functioning correctly before starting processing, ensuring the electrode is in a floating state and the substrate is securely adsorbed, using a sequence of switch states and voltage checks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switch is provided between the electrode and power supply to control voltage application, then the substrate can be securely adsorbed to the electrostatic chuck, but the switch may fail to apply the desired voltage leading to substrate movement during processing
Solution Approach 1:
The system performs preliminary verification of switch functionality by detecting voltage at the electrode before substrate processing begins. The control unit checks whether the switch correctly applies voltage to the electrode, and only proceeds with processing when the switch is confirmed to be functioning properly, preventing substrate movement issues during actual processing.
Solution Approach 2:
A detector is incorporated to provide feedback about the voltage state at the electrode. The control unit receives detection results and uses this feedback to determine whether to proceed with substrate processing, ensuring that voltage application is verified before processing begins and preventing processing under incorrect voltage conditions.
2Reliability
If voltage is continuously applied to the electrode to maintain substrate adsorption, then the substrate remains securely held, but the substrate may become excessively charged during plasma processing
Solution Approach 1:
The system applies voltage to the electrode in a periodic manner rather than continuously. The switch is controlled to apply voltage only during specific phases (before and after plasma processing), and maintains a floating state during plasma processing. This periodic voltage application ensures substrate adsorption stability while preventing excessive charging during plasma exposure.
Solution Approach 2:
The electrode's electrical state is dynamically adjusted based on processing phase. The control unit changes the electrode from a grounded state (with voltage application) to a floating state (isolated) during plasma processing, and back to grounded state after processing. This dynamic state change optimizes both substrate holding and prevents excessive charging.
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
Ensures accurate substrate adsorption and maintains processing precision by preventing substrate movement and excessive charging, thereby improving processing accuracy and throughput.
Implementation Method 1
an electrostatic chuck provided in a chamber, has an electrode therein, and adsorbs a substrate to be processed using a plasma by a voltage applied to the electrode
Data Source
AI summary
A plasma processing apparatus includes an electrostatic chuck including an electrode, a first switch, a second switch, and a control unit. The control unit controls the first switch and the second switch to be in a closed state, causes a power supply to output a first voltage, and determines that the first switch and the second switch are in the closed state when the first voltage is detected by a detector. Further, after it is determined that the first switch and the second switch are in the closed state, the control unit controls the first switch and the second switch to be in an open state to start a processing of the substrate using the plasma in a state where the electrode is controlled to be in a floating state.