Electrostatic Chuck RF Electrode Layout for Wafer Temperature Uniformity
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Solution Overview
Problem
Existing electrostatic chucks fail to effectively reduce variation in the in-plane temperature distribution of wafers during processes like etching due to the RF electrode acting as a heat source, leading to uneven temperature distribution, particularly on the outer circumferential side of the wafer.
Innovation Solution
The RF electrode is positioned inside the outer circumferential edge of the attraction electrode within the dielectric substrate, with a larger flange section and coolant flow path to manage temperature uniformity, and the seal ring and dots to enhance contact with the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the RF electrode is positioned to extend to or beyond the outer circumferential edge of the attraction electrode, then the RF electrode can effectively generate plasma for the etching process, but temperature variation in the in-plane temperature distribution of the wafer increases
Solution Approach 1:
The patent applies local quality by positioning the RF electrode such that its outer circumferential edge is inside the outer circumferential edge of the attraction electrode when viewed from a direction perpendicular to the wafer placement surface. This localized positioning strategy ensures that the RF electrode generates plasma effectively for etching while avoiding excessive heat generation at the wafer's outer circumferential region, thereby maintaining uniform in-plane temperature distribution across the wafer surface.
2Temperature
If the RF electrode is positioned inside the outer circumferential edge of the attraction electrode, then temperature variation in the wafer is reduced, but the RF electrode's ability to generate plasma may be compromised
Solution Approach 1:
The patent employs parameter changes by optimizing the positional parameter of the RF electrode relative to the attraction electrode. Specifically, the RF electrode is positioned with its outer circumferential edge inside the outer circumferential edge of the attraction electrode when viewed from a direction perpendicular to the wafer placement surface. This parameter optimization allows the RF electrode to maintain sufficient plasma generation capability for effective etching while reducing heat generation at the wafer's outer circumferential region, thus achieving uniform in-plane temperature distribution.
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 configuration reduces temperature variation across the wafer's surface by minimizing heat generation and enhancing thermal conductivity, resulting in a more uniform in-plane temperature distribution.
Implementation Method 1
When a voltage is applied to the attraction electrode, an electrostatic force is generated, and the wafer placed on the dielectric substrate is attracted and held
Implementation Method 2
When a process such as etching is performed on the substrate, Joule heat is generated in the RF electrode and increases temperature of surrounding members in some cases
Data Source
AI summary
An electrostatic chuck includes a dielectric substrate, an attraction electrode provided inside the dielectric substrate, and an RF electrode provided inside the dielectric substrate. The RF electrode is provided in a range where an outer circumferential edge of the RF electrode is positioned inside an outer circumferential edge of the attraction electrode in top view.