Plasma Distribution Control for Uniform Semiconductor Wafer Etching
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Solution Overview
Problem
The increasing complexity and size of semiconductor wafers in the chemical dry etching process lead to challenges in maintaining within-wafer uniformity (WiWU), resulting in non-uniform etching and potential damage to device structures.
Innovation Solution
A wafer fabricating system and method that control plasma in the chemical dry etching process by adjusting the distance between a process gas dispenser and an edge ring surrounding a wafer chuck based on real-time monitoring results, ensuring uniform plasma distribution and etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wafer size is increased to improve production efficiency, then productivity increases, but within-wafer uniformity deteriorates
Solution Approach 1:
The patent applies local quality by adjusting the plasma distribution across different regions of the wafer. Specifically, it modifies the plasma power density at the wafer center versus the edges through controlled gas flow patterns and electromagnetic field distribution, ensuring that each region receives appropriate plasma exposure for uniform etching despite the large wafer size.
Solution Approach 2:
The patent employs dynamic control of plasma parameters during the etching process. It continuously adjusts gas flow rates, RF power levels, and chamber pressure to maintain optimal plasma conditions throughout the process, allowing real-time compensation for uniformity deviations that occur during processing of large wafers.
2Device complexity
If the plasma distribution is not controlled, then the process is simpler, but etching uniformity deteriorates leading to over-etching or under-etching
Solution Approach 1:
The patent implements feedback control by monitoring etching results in real-time using optical emission spectroscopy and other diagnostic tools. The system uses this feedback information to dynamically adjust plasma parameters such as gas flow, RF power, and pressure, thereby maintaining etching uniformity across the wafer surface while preventing over-etching or under-etching.
Solution Approach 2:
The patent controls etching uniformity by systematically varying multiple plasma parameters including gas composition, flow rates, RF power frequency and amplitude, and chamber pressure. These parameter changes are coordinated to optimize plasma distribution and ensure uniform material removal across the entire wafer 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
The system achieves improved uniformity of etching across the semiconductor wafer, reducing the risk of over-etching or under-etching, and enhancing the yield and quality of semiconductor devices.
Implementation Method 1
a plasma coil (152) placed adjacent to the dielectric plate (151)... producing a plasma field between the plasma coil (152) and the wafer chuck (12) to process a semiconductor wafer (5)
Data Source
AI summary
A method for processing a semiconductor wafer is provided. The method includes placing a first semiconductor wafer on a wafer chuck in a process chamber. The method further includes adjusting a distance between a gas dispenser positioned above the wafer chuck and an upper edge ring surrounding the wafer chuck. The method also includes producing a plasma for processing the first semiconductor wafer by exciting a gas dispenser from the gas dispenser after the adjustment. In addition, the method includes removing the first semiconductor wafer from the process chamber.