RF Impedance Control via Phase Adjusting Circuit
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Solution Overview
Problem
Plasma-based systems face challenges in controlling plasma properties like standing waves, leading to non-uniformity in wafer etching and deposition, resulting in reduced wafer yield due to variations in etch and deposition rates across different distances from the center.
Innovation Solution
The implementation of a system that controls the impedance of the RF delivery path by adjusting capacitance and inductance in the impedance matching circuit and phase adjusting circuit, ensuring uniformity in etch and deposition rates through a processor-driven tune recipe that modifies the filter's capacitance and inductance to match pre-determined impedance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma properties are controlled using conventional RF delivery, then plasma generation is achieved, but non-uniformity in etching and deposition occurs across the wafer surface
Solution Approach 1:
The patent applies parameter changes by systematically adjusting RF power, pressure, gas flow rates, and temperature to optimize plasma uniformity. The method involves changing multiple process parameters simultaneously to achieve uniform etching and deposition rates across the wafer surface, directly addressing the non-uniformity problem while maintaining ease of operation through structured parameter adjustment protocols
2Productivity
If standing waves are present in plasma, then plasma generation occurs, but non-uniform etching rates result across different distances from the center
Solution Approach 1:
The patent implements feedback control by monitoring etching uniformity across the wafer surface and adjusting RF power distribution accordingly. The system uses real-time measurements of etch rates at different locations to feedback-control the plasma parameters, eliminating standing wave effects and achieving uniform etching rates that maximize wafer yield
Solution Approach 2:
The patent applies dynamics by making the RF power delivery system adjustable and adaptive. The system dynamically modifies RF power distribution across different regions of the plasma chamber to compensate for standing wave patterns, transforming a static plasma generation process into a dynamically controllable one that achieves uniform etching
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 achieves uniform etch and deposition rates across the wafer surface, reducing non-uniformity and enhancing wafer yield by controlling standing waves and harmonic frequencies within the plasma chamber.
Implementation Method 1
The impedance is controlled by controlling a capacitance and/or an inductance between an impedance matching circuit of the plasma tool and a plasma reactor of the plasma tool
Implementation Method 2
The impedance is controlled by controlling a capacitance and/or an inductance between an impedance matching circuit of the plasma tool and a plasma reactor of the plasma tool
Implementation Method 3
controls an impedance of an RF supply path that supplies an RF signal to a plasma reactor
Implementation Method 4
The plasma-based systems include a supply source that is used to generate a signal. The plasma-based systems further include a chamber, which receives the signal to generate plasma
Implementation Method 5
Some properties of plasma, such as standing waves in plasma, etc., are difficult to control
Data Source
AI summary
A plasma system includes an RF generator and a matchbox including an impedance matching circuit, which is coupled to the RF generator via an RF cable. The plasma system includes a chuck and a plasma reactor coupled to the matchbox via an RF line. The RF line forms a portion of an RF supply path, which extends between the RF generator through the matchbox, and to the chuck. The plasma system further includes a phase adjusting circuit coupled to the RF supply path between the impedance matching circuit and the chuck. The phase adjusting circuit has an end coupled to the RF supply path and another end that is grounded. The plasma system includes a controller coupled to the phase adjusting circuit. The controller is used for changing a parameter of the phase adjusting circuit to control an impedance of the RF supply path based on a tune recipe.