Electrostatic Chuck Electrode Volumetric Resistance Control
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Solution Overview
Problem
Existing electrostatic chuck devices face challenges in achieving in-plane uniformity of electric field strength and plasma processing due to variations in volumetric resistance of the electrostatic-adsorption inner electrode, which are influenced by conductive component proportions and temperature fluctuations during fabrication, leading to uneven plasma distribution and inadequate responsiveness of the electrostatic adsorption force.
Innovation Solution
The electrostatic chuck device incorporates an electrostatic-adsorption inner electrode made of a complex sintered body containing insulating ceramics and silicon carbide, with a volumetric resistance set within the range of 1.0×10−1 Ωcm to 1.0×105 Ωcm, ensuring stability across varying temperatures and component ratios, allowing for uniform plasma density and enhanced electrostatic adsorption force responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the frequency of high-frequency power is increased to generate low-energy and high-density plasma, then plasma electron density is improved, but electric field strength distribution becomes uneven and plasma in-plane uniformity deteriorates
Solution Approach 1:
The patent applies local quality by making the electrostatic-adsorption inner electrode non-uniform in its conductive component distribution. The electrode has a higher concentration of conductive components (such as silicon carbide) in the central region compared to the peripheral region. This non-uniform composition creates a corresponding non-uniform volumetric resistance distribution that compensates for the natural electric field concentration at the center, thereby achieving uniform plasma generation across the entire wafer surface even at high frequencies
Solution Approach 2:
The patent changes the physical parameter of volumetric resistance by controlling the proportion of conductive components in the sintered body. By adjusting the content of conductive materials like silicon carbide in the electrostatic-adsorption inner electrode, the volumetric resistance is optimized to maintain even electric field distribution. This parameter adjustment allows the electrode to function effectively at higher frequencies while preserving plasma uniformity
2Force
If the proportion of conductive components in the electrostatic-adsorption inner electrode is increased to improve electrostatic adsorption force, then adsorption strength is improved, but volumetric resistance becomes unstable and responds slowly to temperature changes
Solution Approach 1:
The patent optimizes the volumetric resistance parameter by precisely controlling the proportion of conductive components within a specific range (5-20 wt% silicon carbide). This parameter optimization ensures that the electrode maintains sufficient electrostatic adsorption force while keeping volumetric resistance stable and responsive to temperature changes, preventing both excessive adsorption and resistance instability
Solution Approach 2:
The patent uses composite materials by combining insulating ceramic base materials with conductive components (silicon carbide, metal particles, or carbon) in specific proportions. This composite structure allows the electrode to simultaneously achieve the necessary electrostatic adsorption properties and stable volumetric resistance characteristics, as the insulating matrix provides structural stability while the conductive additives provide the required electrical properties
3Power
If high-frequency power is applied to generate plasma, then plasma processing capability is improved, but electric field strength becomes concentrated at the center and decreases at the periphery
Solution Approach 1:
The patent applies local quality by creating a non-uniform conductive component distribution within the electrostatic-adsorption inner electrode. The central region contains a higher concentration of conductive materials compared to the peripheral region. This spatial variation in composition creates a corresponding variation in volumetric resistance that compensates for the natural electric field concentration at the center, resulting in a more uniform electric field distribution across the entire processing area
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 maintains consistent volumetric resistance, enabling uniform plasma processing and superior electrostatic adsorption force action, even under temperature and composition variations, resulting in improved in-plane uniformity and processing efficiency.
Implementation Method 1
a substrate 4, which has a top surface serving as a mounting surface 4a, on which a plate-like sample W such as a semiconductor wafer is disposed, so as to adsorb the plate-like sample W in an electrostatic manner
Implementation Method 2
by allowing the high-frequency voltage generating source 8 to apply high-frequency power across the metal base section 3 (lower electrode) and an upper electrode (not shown), a high-frequency electric field is generated in the chamber. The high-frequency electric field accelerates electrons, plasma is generated due to ionization by collision of the electrons with the process gas
Data Source
AI summary
An electrostatic chuck device which enables to perform a plasma process having high in-plane uniformity to a plane-like sample by improving the in-plane uniformity of the electric field intensity in a plasma when applied to a plasma processing apparatus. Specifically disclosed is an electrostatic chuck device (21) including an electrostatic chuck section (22), a metal base section (23) serving as a high-frequency generating electrode, and an insulating plate (24). The electrostatic chuck section (22) is composed of a dielectric plate (31) whose top surface (31a) serves as a mounting surface on which a plate-like sample (W) is placed, a supporting plate (32), an electrostatic-adsorption inner electrode (25), and an insulating layer (33). The electrostatic-adsorption inner electrode (25) is made of a composite sintered body containing an insulating ceramic and silicon carbide, while having a volumetric resistance of not less than 1.0×10−1 Ωcm but not more than 1.0×108 Ωcm.