Plasma Processing Antenna Resonant Frequency Control
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in precisely controlling the in-plane distribution of plasma density on substrates, particularly in achieving non-uniform distributions between the central and peripheral regions of substrates during processes like etching, due to limitations in adjusting high-frequency power distribution to monopole antennas connected in parallel.
Innovation Solution
The apparatus incorporates a high-frequency antenna system with a vortex coil configuration, including a first high-frequency antenna element and a second high-frequency antenna element, along with an impedance adjustment unit using variable capacitors to adjust resonant frequencies and control the distribution of high-frequency power between the inner and outer antenna elements, allowing for precise control of plasma density distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple high frequency antennas are used to adjust in-plane plasma density distribution, then plasma density distribution control is improved, but device complexity increases due to requiring multiple high frequency power supplies
Solution Approach 1:
The patent combines multiple monopole antennas (inner and outer antennas) into a single antenna unit that is connected to one high frequency power supply. The antennas are electrically connected in parallel to the single power supply, merging the function of multiple antennas while using a single power source, thus reducing device complexity while maintaining plasma density distribution control capability
Solution Approach 2:
The antenna unit is segmented into multiple monopole antennas (inner antenna and outer antenna) that can be independently positioned and dimensioned. Each antenna element has specific length and position parameters that can be adjusted to control the in-plane plasma density distribution, allowing precise control without requiring multiple power supplies
2Device complexity
If monopole antennas connected in parallel are used, then device complexity is reduced, but the ability to adjust high frequency power distribution to control plasma density is insufficient
Solution Approach 1:
The patent applies local quality by making each monopole antenna element have different physical characteristics (different lengths, different positions, different orientations). The inner antenna and outer antenna have different lengths and are positioned at different locations, creating local variations in electromagnetic field distribution that enable precise control of plasma density at different regions of the substrate
Solution Approach 2:
The patent controls plasma density distribution by changing physical parameters of the antenna elements, specifically the length of each monopole antenna and their relative positions. By adjusting these geometric parameters, the electromagnetic field distribution is modified, which in turn controls the plasma density distribution without requiring complex power distribution control
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 configuration enables flexible adjustment of plasma density distribution across the substrate, improving process control and uniformity or non-uniformity as needed, enhancing the precision and effectiveness of plasma-based semiconductor manufacturing processes.
Implementation Method 1
a high frequency antenna for converting the processing gas supplied into the processing chamber into plasma by an inductive coupling
Implementation Method 2
an impedance adjustment unit including a variable capacitor connected to both ends of the second high frequency antenna and a capacitor connected to the second high frequency antenna element, the impedance adjustment unit being configured to adjust a resonant frequency of a circuit viewed from the high frequency power supply
Data Source
AI summary
A plasma processing apparatus includes a plasma generation unit for converting a processing gas into plasma by an inductive coupling. The plasma generation unit includes a first high frequency antenna formed of a vortex coil having open opposite ends and, at a central portion of a line between the open ends, a supply point of a high frequency power and a grounding point grounded through a capacitor; a second high frequency antenna formed of a planar vortex coil disposed between first and second high frequency antenna elements of the first high frequency antenna; and an impedance adjustment unit for adjusting a resonant frequency of a circuit viewed from a high frequency power supply toward the first high frequency antenna which is configured to have two resonant frequencies depending on adjustment of the impedance adjustment unit when the frequency of the high frequency power is changed.