Dielectric Plate Structure for Uniform VHF/UHF Plasma Processing
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Solution Overview
Problem
Plasma processing apparatuses with VHF or UHF frequency excitation face challenges in achieving uniform plasma distribution due to standing wave generation, which affects the uniformity of plasma in the processing area.
Innovation Solution
Incorporating a dielectric plate with a conductive film connected to the upper electrode and a thickness distribution in the radial direction to function as a capacitor, reducing standing wave generation and adjusting the wavelength of surface waves for improved plasma uniformity, along with a high frequency shield and gas flow paths for independent gas supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VHF or UHF frequency excitation is used in plasma processing, then plasma processing efficiency is improved, but standing wave generation occurs causing non-uniform plasma distribution
Solution Approach 1:
A dielectric plate is introduced as an intermediary component between the upper electrode and the plasma processing chamber. This dielectric plate with specific thickness distribution (thinner at center, thicker at periphery) acts as a mediator to modify the electric field distribution and suppress standing wave formation, thereby maintaining plasma uniformity while using VHF/UHF frequency excitation for efficient processing
2Manufacturing precision
If a dielectric plate with conductive film is added to suppress standing waves, then plasma uniformity is improved, but device complexity increases
Solution Approach 1:
The invention merges multiple functions into a single integrated component: the dielectric plate simultaneously serves as an electrical insulator, a mechanical support structure, and a standing wave suppression element. By combining these functions in one component with optimized thickness distribution, the patent avoids adding separate complex systems while achieving plasma uniformity improvement
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
The solution effectively suppresses standing wave generation and enhances plasma uniformity by adjusting the electric field gradient and surface wave propagation, leading to improved plasma processing outcomes.
Implementation Method 1
The waveguide has an end and guides high frequency waves in a VHF band or a UHF band. The end is arranged to face the space and radiates high frequency waves to the space.
Implementation Method 2
The dielectric plate includes a conductive film. The conductive film is provided on an upper surface of the dielectric plate. The upper surface faces the upper electrode. The conductive film is electrically connected to the upper electrode.
Data Source
AI summary
The plasma processing apparatus according to an exemplary embodiment includes a processing container, a stage, an upper electrode, a dielectric plate, and a waveguide. The stage is provided in the processing container. The dielectric plate is provided above the stage with a space in the processing container interposed therebetween. The upper electrode is provided above the dielectric plate. The waveguide has an end and guides high frequency waves in a VHF band or a UHF band. The end is arranged to face the space to radiate high frequency waves to the space. The dielectric plate includes a conductive film. The conductive film is provided on an upper surface of the dielectric plate. The upper surface faces the upper electrode. The conductive film is electrically connected to the upper electrode.