Upper Electrode Gas Distribution for Uniform Plasma Etching
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving uniformity of plasma processes across the substrate, particularly in terms of plasma density and film state uniformity, leading to non-uniform etching results due to non-uniform gas distribution and plasma density variations between the central and peripheral portions of the substrate.
Innovation Solution
The apparatus incorporates an upper electrode assembly with a gas diffusion plate and insulating plate featuring annular protrusions and strategically arranged gas introduction holes, including inner, outer, and additional outer annular protrusions, to optimize gas distribution and plasma density uniformity, using multiple gas introduction paths to control gas flow and prevent non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional upper electrode assembly is used, then the structure is simple, but the plasma density and gas distribution become non-uniform across the substrate
Solution Approach 1:
The upper electrode assembly is segmented into multiple functional layers: gas diffusion plate with first and second gas supply ports, insulating plate with inner and outer annular protrusions, and electrode plate with through holes. Each layer performs a specific function in gas distribution and plasma generation, enabling uniform plasma density across the substrate by dividing the gas supply system into multiple controlled pathways.
Solution Approach 2:
Different regions of the electrode assembly are designed with different properties: the inner annular protrusion area provides first gas supply for central substrate regions, while the outer annular protrusion area provides second gas supply for peripheral regions. The gas diffusion plate and insulating plate create localized gas distribution zones that match the spatial requirements of the substrate surface, ensuring uniform plasma processes across different locations.
2Manufacturing precision
If gas is supplied uniformly across the substrate, then the gas distribution is even, but plasma density variations occur between central and peripheral portions
Solution Approach 1:
The gas supply system is segmented into at least two independent gas supply paths: first gas supply ports connected to the inner annular protrusion for central region gas delivery, and second gas supply ports connected to the outer annular protrusion for peripheral region gas delivery. This segmentation allows independent control of gas flow rates and compositions to different substrate regions, compensating for natural plasma density variations and achieving uniform plasma processes across the entire substrate.
Solution Approach 2:
The system changes gas supply parameters (flow rate, pressure, composition) differently for central and peripheral regions. By adjusting the parameters of first and second gases supplied through different pathways, the plasma density can be optimized and equalized across the substrate surface, addressing the non-uniformity issue without requiring a single uniform gas supply configuration.
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 enhances plasma process uniformity by concentrating plasma density and gas distribution uniformly across the substrate, improving the consistency of etching processes and film formation, thereby ensuring uniformity of etching hole sizes and film states.
Implementation Method 1
at least one RF power supply coupled to the lower electrode
Implementation Method 2
gas diffusion plate having at least one first gas supply port for a first gas and at least one second gas supply port for a second gas
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber; a substrate support; a lower electrode; an RF power supply; and an upper electrode assembly. The upper electrode assembly includes a gas diffusion plate; an insulating plate; and an upper electrode plate arranged between the gas diffusion plate and the insulating plate, and having a plurality of first through holes and a plurality of second through holes. The insulating plate includes an inner annular protrusion and an outer annular protrusion protruding downward from a lower surface of the insulating plate, and the insulating plate has a plurality of first gas introduction holes, a plurality of second gas introduction holes, and a plurality of third gas introduction holes.