Electrostatic Chuck Gas Outlet Structure to Suppress Abnormal Discharge
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Solution Overview
Problem
Existing plasma processing apparatuses face issues with abnormal discharge during plasma processing, which can affect the efficiency and reliability of the process.
Innovation Solution
The apparatus incorporates a substrate support with a ceramic member featuring a gas diffusion channel and gas outlets with cavity and porous portions to enhance heat transfer and suppress abnormal discharge, utilizing a DC power supply for chuck electrode voltage application and a bias power supply for voltage pulse sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas outlets with simple structure are used in plasma processing apparatus, then device complexity is reduced, but abnormal discharge occurs affecting process reliability
Solution Approach 1:
The gas outlets are filled with ceramic porous material that has specific pore size distribution (average pore diameter 1-10 μm, porosity 30-70%). This porous structure suppresses abnormal discharge by controlling gas flow and preventing discharge initiation, while the material itself provides the necessary structural support without requiring additional complex components.
Solution Approach 2:
The gas outlets are constructed as composite structures combining a cavity portion (horizontal extension from branch paths), a porous portion (vertical extension filled with ceramic porous material), and an opening portion. This composite design integrates multiple functions (gas distribution, discharge suppression, structural support) into a single integrated component, reducing overall device complexity while improving reliability.
2Temperature
If heat transfer gas flow rate is increased to improve temperature control, then temperature control efficiency is improved, but gas consumption and pressure requirements increase
Solution Approach 1:
The gas diffusion channel system provides localized gas distribution with different flow characteristics in different regions. The main path and multiple branch paths create localized gas flow zones that efficiently transfer heat to specific areas of the substrate support, improving temperature control efficiency without requiring high overall gas flow rates.
Solution Approach 2:
The ceramic porous material in the gas outlets provides high surface area for gas-heat transfer interaction. The porous structure (30-70% porosity, 1-10 μm average pore diameter) enables efficient heat transfer at lower gas flow rates by increasing the contact surface area between the heat transfer gas and the substrate support, thereby reducing overall gas consumption.
3Stability of the object's composition
If gas diffusion channel has multiple branch paths for uniform gas distribution, then gas flow uniformity is improved, but channel complexity increases
Solution Approach 1:
The gas diffusion channel is segmented into a main path and multiple branch paths that extend in different directions. This segmentation allows uniform gas distribution across the substrate support by delivering gas through multiple separate channels rather than a single complex network, simplifying the overall structure while maintaining gas flow uniformity.
Solution Approach 2:
The gas diffusion channel system utilizes three-dimensional spatial arrangement with the main path extending in one direction and branch paths extending in another direction from the main path. This dimensional approach enables efficient gas distribution throughout the substrate support volume without requiring overly complex channel geometries, achieving uniform gas delivery through strategic spatial positioning.
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 improves heat transfer and suppresses abnormal discharge, enhancing the verticality and productivity of plasma etching processes while maintaining efficient gas flow and temperature control.
Implementation Method 1
a porous portion extending in the longitudinal direction from the cavity portion to the substrate supporting surface and filled with a ceramic porous material
Implementation Method 2
a heat transfer gas supply configured to supply a heat transfer gas to the gas inlet
Implementation Method 3
an electrostatic chuck for use in a plasma processing apparatus, comprising a ceramic member having a substrate supporting surface
Implementation Method 4
a plasma processing apparatus that suppresses abnormal discharge and an electrostatic chuck
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber and a substrate support disposed in the plasma processing chamber. The substrate support includes a ceramic member having a substrate supporting surface and a back surface, a chuck electrode layer, a bias electrode layer, a gas diffusion channel horizontally extending in the ceramic member and having a main path and branch paths branched from the main path, a gas inlet vertically extending from the back surface to the gas diffusion channel in the ceramic member, and gas outlets communicating with the gas diffusion channel. Each gas outlet has a cavity portion horizontally extending from at least one of the branch paths and a porous portion vertically extending from the cavity portion to the substrate supporting surface and filled with a ceramic porous material.