Electrostatic Chuck Temperature Control with Guard Electrode
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Solution Overview
Problem
In plasma etching apparatuses, achieving uniformity in the etching rate and temperature control of wafers is challenging due to variations in plasma density and surface temperature, requiring precise control of in-plane temperature distribution, which is complicated by the increased number of heaters in electrostatic chuck devices.
Innovation Solution
The electrostatic chuck device incorporates a high-frequency generating electrode, a guard electrode, and multiple heaters with heat transfer barriers to isolate and control temperature zones, reducing the influence of high-frequency interference and enhancing temperature uniformity through a layered structure and strategic placement of heat transfer barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple heaters are added to control in-plane temperature distribution, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The heating system is divided into multiple independent heater zones (first heater, second heater, third heater) that can be controlled separately. Each heater corresponds to a specific radial region of the wafer, allowing independent temperature control in different zones to achieve uniform in-plane temperature distribution
Solution Approach 2:
Different heater zones are designed with different heating characteristics to match the local thermal requirements of different wafer regions. The first heater controls the central region, while the second and third heaters control peripheral regions, with each zone having optimized heating power and control parameters for its specific location
2Adaptability or versatility
If high frequency generating electrode is added for plasma generation, then plasma generation capability is improved, but high frequency interference with heater increases
Solution Approach 1:
A ground electrode is introduced as an intermediary component between the high frequency generating electrode and the heater elements. This ground electrode acts as a shield that intercepts and redirects high frequency electromagnetic fields, preventing them from directly interfering with the heater circuits while maintaining plasma generation functionality
Solution Approach 2:
The harmful high frequency interference is extracted and isolated from the heater system by using the ground electrode to capture and divert the electromagnetic fields away from the heater elements, separating the plasma generation function from the heating function to eliminate mutual interference
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 allows for precise and uniform temperature control across the wafer, improving etching rate uniformity and stability in film formation by minimizing high-frequency interference and heat conduction issues, thus simplifying the device configuration and reducing manufacturing costs.
Implementation Method 1
generates electric charges in the electrode for electrostatic attraction, and fixes the plate-shaped sample to the mounting surface with an electrostatic attraction force
Implementation Method 2
the wafer is cooled from the lower side by circulating a cooling medium such as water through a temperature controlling base part
Implementation Method 3
a heater member is mounted between an electrostatic chuck part and a temperature controlling base part
Data Source
AI summary
An aspect of the present invention has an object to provide an electrostatic chuck device which is provided with a plurality of divided heaters and in which uniform temperature control of a zone which is heated by each heater can be performed with a simple configuration. An electrostatic chuck device according to an aspect of the present invention includes: an electrostatic chuck part which has a mounting surface on one principal surface thereof to mount a plate-shaped sample and has an electrode for electrostatic attraction; a temperature controlling base part which is provided at a side opposite to the mounting surface of the electrostatic chuck part and is configured to cool the electrostatic chuck part; a high frequency generating electrode which is provided in a layer between the electrostatic chuck part and the temperature controlling base part; a high frequency power source which is connected to the high frequency generating electrode; a first heater element which is configured with a plurality of main heaters which are provided in a layer between the high frequency generating electrode and the temperature controlling base part; and a guard electrode which is provided in a layer between the high frequency generating electrode and the first heater element.