Focus Ring Plasma Direction Control for Uniform Wafer Etching
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Solution Overview
Problem
In the manufacturing of integrated circuits, existing patterning techniques face challenges in achieving uniform critical dimensions of patterned features across a wafer, leading to performance degradation due to process limitations.
Innovation Solution
The method involves using a plasma processing apparatus with a focus ring and an edge electric field generator to control the RF electromagnetic field over the peripheral region of the wafer, adjusting the plasma direction based on the thickness of the focus ring to maintain uniform plasma concentration across the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional patterning techniques are used, then manufacturing process is simple, but critical dimensions of patterned features are not uniform across the wafer
Solution Approach 1:
The patent applies local quality by creating a non-uniform RF electromagnetic field distribution across the wafer surface using an edge electric field generator. The generator produces enhanced electric fields at the peripheral regions while maintaining different field characteristics at the center region, thereby achieving uniform plasma concentration and etching profiles across areas that previously exhibited non-uniformity due to edge effects.
Solution Approach 2:
The patent changes the RF electromagnetic field parameters (electric field strength and distribution) across different regions of the processing chamber. By adjusting the field parameters at the wafer periphery through the edge electric field generator, the plasma generation and etching rates are optimized to achieve uniform critical dimensions across the entire wafer surface.
2Manufacturing precision
If edge effects are not compensated, then processing is simpler, but plasma concentration is non-uniform across the wafer
Solution Approach 1:
The patent introduces an edge electric field generator as an intermediary component between the RF power source and the wafer. This generator acts as a mediator that shapes and distributes the RF electromagnetic field to compensate for edge effects, creating the desired non-uniform field distribution that results in uniform plasma concentration across the wafer surface.
3Manufacturing precision
If plasma direction is not adjusted, then processing is faster, but etching profiles are non-uniform at peripheral regions
Solution Approach 1:
The patent applies local quality by directing plasma flux differently across various regions of the wafer. The edge electric field generator creates enhanced electric fields at the periphery that guide plasma ions to strike the wafer surface at optimized angles and with controlled energy, achieving uniform etching profiles that match the center region while accounting for local geometric differences.
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 approach ensures uniform etching profiles across the wafer, improving device performance and reducing fabrication costs by maintaining consistent plasma direction and concentration.
Implementation Method 1
control the RF electromagnetic field over the peripheral region of the wafer
Implementation Method 2
A plasma is formed in the processing chamber to process the wafer
Implementation Method 3
edge electric field generator to control the RF electromagnetic field
Data Source
AI summary
A method for manufacturing a semiconductor structure includes disposing a wafer in a processing chamber, in which the wafer is laterally surrounded by a focus ring. A plasma is formed in the processing chamber to process the wafer. A thickness of the focus ring is detected. A plasma direction of the plasma over a peripheral region of the wafer is adjusted according to the thickness of the focus ring.