Pulsed Gas Injection for Etch Uniformity
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Solution Overview
Problem
Current semiconductor wafer etching processes using plasma technologies face challenges in achieving uniform etching across the substrate surface, with existing methods often resulting in significant differences in etch product distribution from the center to the edge, leading to non-uniform feature formation.
Innovation Solution
A method involving a plasma chamber with inner and outer injection zone gas feeds, where pulsed etch gas is provided from both feeds at a synchronized but out-of-phase frequency, allowing for independent duty cycles and uniform etch gas distribution, utilizing a plasma processing system with RF power and a fast switch to manage gas pulses, ensuring consistent etching across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous plasma etching is used, then productivity is improved, but manufacturing precision deteriorates due to non-uniform etch distribution from center to edge
Solution Approach 1:
The patent applies periodic pulsed gas flow to the plasma etching system, where gas is supplied in alternating pulses to different zones of the chamber. This periodic action allows the plasma chemistry to be dynamically controlled, enabling uniform etching across the substrate while maintaining continuous processing throughput.
Solution Approach 2:
The system dynamically adjusts gas flow rates and timing between inner and outer injection zones during the etching process. By rapidly switching gas flows and adjusting plasma parameters in real-time, the system achieves uniform etch distribution without sacrificing productivity.
2Device complexity
If single zone gas feed is used, then device complexity is reduced, but manufacturing precision deteriorates due to non-uniform etch product distribution
Solution Approach 1:
The gas feed system is segmented into multiple independent zones (inner and outer injection zones) that can be controlled separately. This segmentation allows different regions of the plasma chamber to receive gas pulses at different times and rates, achieving uniform etching across the substrate while maintaining manageable system complexity.
Solution Approach 2:
Different zones of the plasma chamber receive tailored gas flows optimized for their specific requirements. The inner and outer injection zones provide locally optimized gas distribution, ensuring uniform etch properties across different regions of the 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 approach results in a more uniform etch across the substrate surface, reducing the percent difference in etch product distribution between the center and edge, enhancing the uniformity and consistency of feature formation during semiconductor wafer processing.
Implementation Method 1
The etch gas is formed into a plasma to etch the layer
Implementation Method 2
At least one RF power source is electrically connected to the at least one electrode
Data Source
AI summary
A method for etching a layer in a plasma chamber with an inner injection zone gas feed and an outer injection zone gas feed is provided. The layer is placed in the plasma chamber. A pulsed etch gas is provided from the inner injection zone gas feed at a first frequency, wherein flow of pulsed etch gas from the inner injection zone gas feed is ramped down to zero. The pulsed etch gas is provided from the outer injection zone gas feed at the first frequency and simultaneous with and out of phase with the pulsed etch gas from the inner injection zone gas feed. The etch gas is formed into a plasma to etch the layer, simultaneous with the providing the pulsed etch gas from the inner injection zone gas feed and providing the pulsed gas from the outer interjection zone gas feed.