Electrostatic Chuck Dielectric Layer Segmentation
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Solution Overview
Problem
Existing electrostatic chucks in semiconductor manufacturing face issues with residual suction force, which can lead to decreased throughput and potential damage during wafer demounting, particularly in plasma etching processes where stricter conditions exacerbate this problem.
Innovation Solution
The electrostatic chuck design incorporates a dielectric layer structure with a lower relative permittivity beneath the electrostatic electrode and a higher relative permittivity above it, reducing parasitic capacity and residual suction force by optimizing the materials and porosity of the dielectric layers to enhance charge dissipation and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single dielectric layer with high relative permittivity is used in the electrostatic chuck, then the suction and holding force is improved, but the residual suction force increases causing difficulty in wafer demounting
Solution Approach 1:
The dielectric layer is divided into two distinct layers: a first dielectric layer with lower relative permittivity (5-10) and a second dielectric layer with higher relative permittivity (10-20). This segmentation allows each layer to perform different functions - the first layer reduces parasitic capacity and residual suction force, while the second layer provides strong suction and holding force, thereby resolving the contradiction between holding force and ease of demounting.
Solution Approach 2:
Different regions of the dielectric structure are assigned different material properties. The first dielectric layer (closer to the electrostatic electrode) has lower relative permittivity to minimize parasitic capacity, while the second dielectric layer (closer to the wafer) has higher relative permittivity to maximize holding force. This local differentiation of material properties optimizes both suction force and demounting ease simultaneously.
2Force
If moisture is present on the contact surface between the electrostatic chuck and wafer, then the relative permittivity increases enhancing suction force, but the residual suction force increases considerably deteriorating separability
Solution Approach 1:
The harmful effect of moisture-induced high relative permittivity is extracted and isolated to only the second dielectric layer, while the first dielectric layer maintains low relative permittivity regardless of moisture presence. This extraction ensures that even if moisture accumulates, the overall parasitic capacity remains controlled, and separability is maintained while still benefiting from enhanced holding force where needed.
3Force
If the dielectric layer thickness is increased to improve holding force, then the suction force is enhanced, but the charge dissipation time increases leading to prolonged residual suction force
Solution Approach 1:
The relative permittivity parameter is changed across different layers to optimize both holding force and charge dissipation. By setting the first dielectric layer with lower relative permittivity (5-10) and the second with higher relative permittivity (10-20), the system achieves sufficient holding force through the second layer while the first layer ensures rapid charge dissipation, reducing residual suction force duration.
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 design effectively reduces residual suction force, improving wafer demounting efficiency and preventing damage, while maintaining sufficient suction and holding force, thus enhancing the overall processing throughput and reliability.
Implementation Method 1
a relative permittivity of the first dielectric layer is lower than a relative permittivity of the second dielectric layer
Implementation Method 2
an electrostatic electrode; and a base body in which the electrostatic electrode is embedded
Implementation Method 3
the second dielectric layer has a first surface facing the first dielectric layer and a second surface opposite to the first surface, and the second surface is a placement surface on which a suction target is placed
Data Source
AI summary
An electrostatic chuck includes at least one conductor layer; an electrostatic electrode; and a base body in which the electrostatic electrode is embedded, the base body having a first dielectric layer on which the electrostatic electrode is mounted, the base body having a second dielectric layer stacked on the first dielectric layer with covering the electrostatic electrode. The conductor layer is formed on a surface of the first dielectric layer opposite to a surface on which the electrostatic electrode is mounted. The second dielectric layer has a first surface facing the first dielectric layer and a second surface opposite to the first surface, and the second surface is a placement surface on which a suction target is placed. A relative permittivity of the first dielectric layer is lower than a relative permittivity of the second dielectric layer.