Electrostatic Chuck Electrode Inspection Using Capacitance Mapping
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Solution Overview
Problem
Inspecting the quality of a DC electrode within an electrostatic chuck is challenging due to its insertion in a ceramic dielectric layer, making non-destructive evaluation difficult.
Innovation Solution
An apparatus and method utilizing a measurement unit to measure capacitance of both the dielectric layer and the electrode, with a control unit evaluating the electrode's quality based on area and asymmetry by calculating the electrode's area using dielectric layer capacitance and permittivity, and comparing it to reference values, and assessing asymmetry through capacitance measurements across sub-areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DC electrode is inserted in a ceramic dielectric layer to enable electrostatic chucking, then the electrostatic chuck can hold the substrate, but the DC electrode becomes difficult to inspect for quality
Solution Approach 1:
The patent uses capacitance as an intermediary parameter to indirectly measure electrode quality. Instead of directly inspecting the embedded electrode, the system measures capacitance values that reflect the electrode's area and position, allowing quality assessment without physical access to the electrode itself.
Solution Approach 2:
The patent replaces direct physical inspection methods with electrical measurement methods. By using capacitance measurement circuits to detect electrode characteristics through the dielectric layer, the system substitutes mechanical or visual inspection with non-contact electrical sensing.
2Ease of manufacture
If non-destructive inspection methods are used to evaluate the DC electrode, then the electrostatic chuck remains intact, but accurate measurement of electrode quality is challenging
Solution Approach 1:
The patent divides the dielectric layer into multiple measurement regions and measures capacitance at different locations. By segmenting the measurement area and comparing capacitance values across sub-areas, the system achieves precise determination of electrode area and asymmetry without destructive testing.
Solution Approach 2:
The patent measures capacitance under different conditions (different measurement points, different reference values) and uses these parameter variations to extract detailed information about electrode area and position. By changing measurement parameters rather than physical conditions, the system achieves precise non-destructive characterization.
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
Enables non-destructive, accurate evaluation of the DC electrode's quality, ensuring proper chucking performance and preventing defects like He leak or wafer decay by determining area and asymmetry without damaging the electrostatic chuck.
Implementation Method 1
a measurement unit for measuring a first capacitance of a dielectric layer of the electrostatic chuck and for measuring a second capacitance of an electrode installed in the dielectric layer
Data Source
AI summary
An apparatus and a method for non-destructive inspection of quality of an electrostatic chuck are disclosed. The apparatus includes a measurement unit for measuring a first capacitance of a dielectric layer of the electrostatic chuck and for measuring a second capacitance of an electrode installed in the dielectric layer; and a control unit configured to evaluate quality of the electrode, based on the first capacitance and the second capacitance.