Electrostatic Chuck Heater Plate Design for RF Shielding
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Solution Overview
Problem
Existing electrostatic chucks face challenges in simultaneously achieving temperature uniformity, rapid temperature increase, and high reliability under thermal, electrical, and mechanical loads, especially when subjected to RF voltage and plasma processing, which affects the heater's performance and insulation breakdown voltage.
Innovation Solution
The electrostatic chuck design incorporates a ceramic dielectric substrate, a base plate, and a heater plate with a specific configuration of support plates, resin layers, and a bypass layer to enhance temperature uniformity, shield the heater from high-frequency waves, and improve adhesion and withstand voltage characteristics, allowing for independent temperature control of the processing object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a general heater is used in the electrostatic chuck, then the heater can generate heat, but the heater is affected by high frequency waves and generates abnormal heat, reducing reliability
Solution Approach 1:
The heater plate is constructed as a composite structure with a dielectric substrate and a metal layer, where the dielectric material provides resistance to high frequency waves while the metal layer provides thermal conductivity for effective heating. This composite design allows the heater to function reliably under RF voltage conditions without abnormal heat generation.
2Temperature
If the heater is built into the electrostatic chuck, then temperature control is achieved, but the heater cannot withstand high frequency voltage and has poor insulation breakdown characteristics
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the metal heater layer and the high frequency voltage source. This dielectric substrate acts as a mediator that provides electrical insulation and prevents insulation breakdown while allowing thermal energy to pass through to the wafer, thus maintaining both temperature control and high withstand voltage characteristics.
3Temperature
If temperature control is improved, then temperature uniformity and controllability are achieved, but the structure becomes more complex
Solution Approach 1:
The heater plate structure is designed to perform multiple functions simultaneously: the dielectric substrate provides both electrical insulation against high frequency waves and thermal insulation to control heat distribution, while the metal layer provides thermal conductivity for heating. This multi-functional design achieves temperature uniformity and controllability without requiring additional separate components, thus avoiding increased structural complexity.
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 improves the electrostatic chuck's ability to maintain uniform temperature distribution, increase the temperature increase rate, and enhance reliability by reducing thermal stress and peeling, while maintaining high withstand voltage and thermal uniformity.
Implementation Method 1
a heater element provided between the first support plate and the second support plate, the heater element emitting heat due to a current flowing
Implementation Method 2
The electrostatic chuck applies electrical power for electrostatic attraction to a built-in electrode and attracts and holds a substrate such as a silicon wafer, etc., by an electrostatic force
Data Source
AI summary
An electrostatic chuck includes: a ceramic dielectric substrate; a base plate; and a heater plate. The heater plate includes a first and a second support plates including a metal, a heater element provided between the first and the second support plates, a first resin layer provided between the first support plate and the heater element, and a second resin layer provided between the second support plate and the heater element. A surface of the first support plate on the second support plate side includes a first region and a second region, the first region overlapping the heater element when viewed along the stacking direction, the second region not overlapping the heater element when viewed along the stacking direction. In a cross section parallel to the stacking direction, the second region protrudes toward the second support plate side compared to the first region.