Shower Plate Electrode Layout for Uniform Plasma Distribution
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving in-plane uniformity of plasma distribution on a stage, leading to non-uniform film formation and etching processes.
Innovation Solution
A shower plate design with an upper dielectric and embedded upper electrode, where the distance between the dielectric and electrode is shorter in the peripheral portion than the central portion, corrects the electric field vector, enhancing the in-plane uniformity of the sheath electric field and plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional shower plate with uniform electrode-dielectric distance is used, then the structure is simple and easy to manufacture, but the in-plane uniformity of plasma distribution on the stage deteriorates
Solution Approach 1:
The shower plate is designed with non-uniform thickness, where the dielectric layer has different thicknesses in different regions (thinner at center, thicker at periphery). This local variation in structure creates corresponding variations in the distance between the electrode and dielectric surface, allowing different regions to have optimized electric field characteristics for achieving uniform plasma distribution across the stage.
2Manufacturing precision
If the distance between dielectric and electrode is uniform, then the manufacturing process is simple, but the electric field uniformity and plasma distribution uniformity worsen
Solution Approach 1:
The dielectric layer is designed with spatially varying thickness to create local differences in the electrode-dielectric distance. The center region has a smaller distance while the peripheral region has a larger distance, which compensates for the natural tendency of electric field non-uniformity in plasma processing and achieves uniform electric field distribution across the processing area.
3Manufacturing precision
If a conventional uniform shower plate is used, then device complexity is low, but film formation uniformity and etching uniformity deteriorate
Solution Approach 1:
The non-uniform thickness design of the dielectric layer creates region-specific electric field characteristics that optimize plasma distribution. This local optimization ensures that both central and peripheral regions of the stage receive appropriate plasma flux, resulting in uniform film formation and etching across the entire substrate surface.
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 in-plane uniformity of plasma on the stage, suppressing undesired ion movement and enhancing the uniformity of plasma processing, such as film formation and etching.
Implementation Method 1
A sheath electric field that produces plasma is strong in a central portion of a stage
Implementation Method 2
generates plasma by using radio frequency waves having a frequency of the very high frequency (VHF) band
Implementation Method 3
an electric field vector tends to be inclined and weakened in a peripheral portion of the stage
Data Source
AI summary
In a shower plate, a plasma processing apparatus, and a plasma processing method, improvement of in-plane uniformity of plasma on a stage is required. The shower plate according to an exemplary embodiment includes an upper dielectric disposed to face a stage and an upper electrode embedded in the upper dielectric. A distance between a bottom surface of the upper dielectric and the upper electrode is shorter in a peripheral portion than in a central portion.