Bent Gas Holes in Plasma Etching Electrode Plates
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Solution Overview
Problem
In plasma etching processes, the widening of gas holes in electrode plates due to plasma exposure leads to uneven etching rates and abnormal discharges, causing damage and contamination within the chamber.
Innovation Solution
The electrode plate is divided into regions with different types of gas holes, including bent type gas holes, which are designed to prevent plasma introduction and reduce abnormal discharges by optimizing the arrangement based on the plasma etching apparatus and process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If straight gas holes are provided in the electrode plate, then gas introduction efficiency is improved, but plasma is easily introduced into the gas holes causing abnormal discharge
Solution Approach 1:
The gas holes are designed with curved or bent configurations instead of straight lines. The curvature causes plasma to collide with the hole walls and change direction, preventing direct plasma introduction while maintaining gas flow efficiency through the electrode plate.
2Manufacturing precision
If gas holes are provided on concentric circles, then etching uniformity is improved, but plasma exposure widens the holes causing process instability
Solution Approach 1:
Curved gas holes resist plasma erosion better than straight holes, maintaining their dimensional stability and preventing the trumpet-shaped widening that occurs with straight holes. This preserves etching uniformity over extended operational periods.
Solution Approach 2:
Different regions of the electrode plate have gas holes with different curvature radii adapted to local plasma density conditions. High plasma density regions use holes with larger curvature radii for better protection, while low density regions use holes with smaller curvature radii to maintain gas flow efficiency.
3Object-affected harmful factors
If magnets are added to create zero-magnetic field regions, then plasma introduction into gas holes is reduced, but device complexity increases
Solution Approach 1:
The magnetic field control function is extracted and replaced by the geometric configuration of the gas holes themselves. The curved hole structures inherently prevent plasma introduction through their shape, eliminating the need for separate magnet components while achieving the same protective effect.
4Object-affected harmful factors
If bent gas holes are used, then plasma introduction is prevented, but manufacturing difficulty increases
Solution Approach 1:
The curvature radius of the gas holes is optimized to balance plasma protection and manufacturability. By selecting appropriate curvature parameters, the holes provide effective plasma shielding while remaining feasible to manufacture using standard drilling and shaping processes.
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 effectively prevents abnormal discharges on the rear surface of the upper electrode, maintains stable process characteristics, and extends the lifespan of the electrode plate by reducing plasma exposure and particle generation.
Implementation Method 1
inner portions of the gas holes are worn away by the plasma, and thus, the gas holes are widened toward the plasma generating space similar to trumpet shapes
Data Source
AI summary
An electrode plate for a plasma etching is formed as a disc shape having a predetermined thickness, a plurality of gas holes penetrating a surface of the electrode plate perpendicularly to the surface are provided on different circumferences of a plurality of concentric circles, the electrode plate is divided in a radial direction of the electrode plate into two or more regions, types of gas holes provided in the two or more regions are different from each other by region.