Electrostatic Chuck Passage Electrodes to Prevent Arc Discharge
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Solution Overview
Problem
Existing semiconductor manufacturing apparatus members fail to adequately prevent abnormal electrical discharge in gas passages, even when shielded by conventional shield electrodes.
Innovation Solution
A member for semiconductor manufacturing apparatus is designed with a ceramic plate having a wafer placement surface and a built-in electrostatic electrode, a base plate with a refrigerant flow path, and inner electrodes electrically coupled to the electrostatic electrode. The inner electrodes are positioned under the electrostatic electrode and not exposed to the gas passage, creating a shorter electric potential gradient that prevents electron acceleration and subsequent arc discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylindrical shield electrode is provided around the gas passage to shield the internal space from the electric field, then the shielding effect is improved, but the abnormal electrical discharge cannot be prevented when shielding is insufficient
Solution Approach 1:
The patent divides the electrostatic electrode into multiple segments: the main electrostatic electrode and multiple inner electrodes positioned at different heights within the ceramic plate. This segmentation allows the electric field to be controlled in stages, preventing electron acceleration along the gas passage while maintaining the necessary electrostatic attraction function.
Solution Approach 2:
The patent transitions from a two-dimensional shielding approach (cylindrical shield around the passage) to a three-dimensional electrode configuration (multiple inner electrodes at different heights within the ceramic plate). This vertical dimensionality change creates multiple electric potential gradient zones that effectively prevent abnormal discharge throughout the gas passage volume.
2Object-affected harmful factors
If the vertical distance of the electric potential gradient is reduced by providing inner electrodes, then electron acceleration is prevented, but the device structure becomes more complex
Solution Approach 1:
The patent merges the inner electrodes with the ceramic plate structure, where the ceramic plate serves as both the structural component and the housing for the electrostatic and inner electrodes. This integration reduces overall device complexity while achieving the desired electric field control.
Solution Approach 2:
The ceramic plate performs multiple functions: it provides structural support, houses the electrostatic and inner electrodes, and creates the gas passage. This multi-functionality reduces the need for separate components, thereby reducing device complexity while maintaining effective electron acceleration prevention.
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
The solution effectively reduces or prevents abnormal electrical discharge in the gas passages by limiting the vertical distance of the electric potential gradient, thereby avoiding electron acceleration and arc discharge.
Implementation Method 1
an electric potential gradient is generated in the internal space of the passage in an up-down direction
Implementation Method 2
a built-in electrostatic electrode
Implementation Method 3
electrons ionized from the atoms or molecules of a heat transfer gas
Data Source
AI summary
A member for semiconductor manufacturing apparatus includes: a ceramic plate having a wafer placement surface on its upper surface and a built-in electrostatic electrode; a base plate provided on a lower surface of the ceramic plate, and configured to include a built-in refrigerant flow path; a passage provided from a lower surface of the base plate to the wafer placement surface of the ceramic plate; at least one inner electrode provided inside the ceramic plate so as to be located in a periphery of the passage under the electrostatic electrode and not to be exposed to an inner wall of the passage, the at least one inner electrode being electrically coupled to the electrostatic electrode; and a bias electrode provided electrically independently from the electrostatic electrode at a height equal to or lower than a height of a lowermost inner electrode of the at least one inner electrode.