Electrostatic Chuck De-Chucking via Lift Pin Load Detection
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Solution Overview
Problem
Conventional electrostatic chucks with simple monopolar electrodes face issues with residual charges causing substrate damage and difficulty in measuring de-chucking states, leading to unreliable substrate processing.
Innovation Solution
A substrate processing apparatus with an electrostatic chuck and a lift pin system that measures the load applied to the lift pin before unloading, allowing for identification of the de-chucking state by comparing the load measurement with a reference value, and applying control signals to ensure safe substrate release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple monopolar electrostatic electrode is used, then the device complexity is reduced, but residual charges are generated that prevent proper de-chucking and cause substrate damage
Solution Approach 1:
The electrostatic electrode is divided into multiple independent electrodes (first electrostatic electrode and second electrostatic electrode) with different polarities. This segmentation allows separate control of charging and de-chucking operations, enabling complete charge dissipation and reliable substrate release without the limitations of a simple monopolar design.
2Measurement precision
If frequent substrate unloading is performed to check de-chucking state, then measurement accuracy is improved, but substrate damage increases due to repeated lifting while chucked
Solution Approach 1:
A load measurement device provides real-time feedback on the load applied to lift pins during substrate handling. The controller monitors this load information to determine the de-chucking state, enabling non-contactless detection without requiring frequent physical substrate retrieval and re-chucking operations.
Solution Approach 2:
The mechanical approach of physically retrieving and re-chucking substrates for inspection is replaced with a load measurement system that electronically monitors the de-chucking state through force sensors on the lift pins, eliminating repeated mechanical stress on the substrate.
3Productivity
If the lift pin lifts the substrate while the electrostatic chuck is still chucking, then the substrate can be removed, but damage or stress is caused to the substrate
Solution Approach 1:
The electrostatic chuck is deactivated to release the substrate before the lift pin initiates lifting motion. The load measurement device confirms complete de-chucking by detecting zero load on the chuck, ensuring the substrate is fully released and floating freely before mechanical contact from the lift pin, thereby preventing damage.
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 enhances the reliability of substrate processing by preventing substrate damage during de-chucking and improving the accuracy of identifying successful de-chucking operations.
Implementation Method 1
an electrostatic chuck body configured to chuck a substrate using an electrostatic force
Implementation Method 2
a load measurement device configured to measure a load applied to the at least one lift pin
Data Source
AI summary
A substrate processing apparatus includes an electrostatic chuck body configured to chuck a substrate using an electrostatic force; a substrate lifting device installed at the electrostatic chuck body and configured to lift the substrate from the electrostatic chuck body; and a controller configured to apply a control signal to the substrate lifting device, wherein the substrate lifting device includes: at least one lift pin movable so as to be in contact with the substrate; a lift pin moving table configured to support the at least one lift pin thereon and to be vertically movable; a moving table lifting device configured to vertically move the lift pin moving table; and a load measurement configured to measure a load applied to the at least one lift pin.