Electrostatic Chuck Dechuck Control Using Supporting Pins
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Solution Overview
Problem
Existing methods for removing residual electrical charge from electrostatic chucks in plasma processing apparatuses are inadequate, leading to potential wafer breakage and failure to remove wafers properly due to remaining attractive forces.
Innovation Solution
A dechuck control method that applies a given voltage to the electrostatic chuck while lifting the processed object with a supporting mechanism, using a control unit to manage the voltage and torque applied to the supporting pins, ensuring the cancellation of residual charge and safe removal of the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage is applied to the chuck electrode to remove remaining electrical charge, then the electrical charge is removed, but the wafer may still not be removed properly due to persistent attractive force
Solution Approach 1:
The supporting pins are positioned to contact the wafer surface in advance before voltage application, and the voltage is applied while the pins are in position, so that when the attractive force is reduced, the pins can immediately support and lift the wafer without delay
Solution Approach 2:
The supporting pins act as an intermediary mechanical element that transfers the lifting force to the wafer, allowing the wafer to be removed even when residual electrical attraction persists, by providing a physical support path that bypasses the electrostatic attraction
2Reliability
If voltage is applied to remove remaining electrical charge, then charge cancellation is achieved, but wafer breakage may still occur due to insufficient charge removal
Solution Approach 1:
The supporting pins are positioned to contact and support the wafer before the voltage application is completed, so that as the charge is being cancelled, the pins gradually take over the support load, preventing sudden wafer movement or breakage that could occur with incomplete charge removal
Solution Approach 2:
The supporting pins provide a cushioning mechanical support structure that prevents wafer breakage by distributing the lifting force and preventing sudden releases or movements that could occur if charge removal is insufficient or uneven
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 method effectively eliminates residual charge on the electrostatic chuck, preventing wafer breakage and ensuring smooth removal by maintaining zero voltage on the chuck, thus facilitating easy dechucking of wafers.
Implementation Method 1
a wafer W is attracted and held on an electrostatic chuck 40 by application of voltage HV to a chuck electrode 40a
Implementation Method 2
a DC power source 42 applies voltage to the chuck electrode 40a. By using the plasma processing apparatus 1, it is possible to easily remove a wafer W
Data Source
AI summary
A dechuck control method of dechucking a processed object electrostatically attracted to an electrostatic chuck is provided. The method includes a step of dechucking the processed object by lifting the processed object with a supporting mechanism. The dechucking step is performed while applying a given voltage to an electrode of the electrostatic chuck.