Plasma Control Circuit Harmonic Resonance Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma processing systems face challenges in achieving uniform plasma distribution, leading to non-uniform etch rates and hotspot issues during semiconductor manufacturing, due to harmonic components of RF power causing increased plasma density at the center of the wafer.
Innovation Solution
A plasma control apparatus and system that utilize a transmission line to deliver RF power with multiple frequencies, a matching circuit to control impedance, and a plasma control circuit to selectively control harmonics at very high frequencies (VHF) through resonance, ensuring uniform plasma distribution by filtering and producing resonance for harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If RF power is delivered to plasma chamber using conventional methods, then plasma is generated for semiconductor processing, but harmonic components cause non-uniform plasma distribution with increased density at wafer center
Solution Approach 1:
The patent applies parameter changes by introducing a plasma control circuit that modifies the electrical parameters (impedance, resonance frequency) of the RF power delivery system. The circuit changes the operating conditions by producing resonance at specific harmonic frequencies (2nd, 3rd, 4th harmonics) to actively control plasma density distribution and achieve uniform etch rates across the wafer surface
2Power
If impedance control is implemented to maximize RF power delivery, then power transfer efficiency is improved, but plasma distribution uniformity deteriorates due to uncontrolled harmonics
Solution Approach 1:
The patent segments the RF power delivery system into distinct functional blocks: a matching circuit for impedance control and power maximization, and a separate plasma control circuit for harmonic resonance control. This segmentation allows independent optimization of power delivery efficiency and plasma distribution uniformity without compromise
Solution Approach 2:
The plasma control circuit acts as an intermediary between the RF power source and plasma chamber. It introduces resonance circuits that selectively control harmonic components, mediating the power transfer to achieve both efficient power delivery and uniform plasma distribution by controlling the electrical characteristics of the RF power
3Reliability
If conventional RF power delivery is used, then plasma generation is achieved, but hotspot issues occur at wafer center due to harmonic components
Solution Approach 1:
The patent converts the harmful harmonic components into beneficial effects by producing controlled resonance at specific harmonic frequencies (2nd, 3rd, 4th harmonics) through the plasma control circuit. Instead of treating harmonics as unwanted interference, the system utilizes them to actively control and uniformize plasma density distribution, eliminating hotspots while maintaining reliable plasma generation
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 solution effectively controls plasma distribution, reducing non-uniformity and hotspot issues by minimizing impedance variations, resulting in more uniform etch rates across the wafer surface.
Implementation Method 1
a plasma control circuit configured to selectively and independently control harmonics at a very high frequency (VHF) among the at least two frequencies, and to control circuit control plasma distribution in the plasma chamber by producing resonance for the harmonics
Implementation Method 2
a filter circuit configured to perform filtering on a fundamental and harmonics with respect to the frequencies of the RF power
Data Source
AI summary
A plasma control apparatus for controlling plasma to be uniformly distributed in a plasma chamber and a plasma processing system including the same are provided. The plasma control apparatus includes a transmission line configured to deliver radio frequency (RF) power to a plasma chamber through at least two frequencies, a matching circuit configured to control impedance for maximum delivery of the RF power, and a plasma control circuit configured to selectively and independently control harmonics at a very high frequency (VHF) among the at least two frequencies and to control plasma distribution in the plasma chamber by producing resonance for the harmonics.