Plasma Processing Coil Inductance Control for Etching Uniformity
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving uniformity and yield in etching treatments due to mutual interference from stray capacitance between electrodes and difficulties in accurately adjusting power supply parameters, leading to deviations in bias potential and etching rate variations.
Innovation Solution
The apparatus adjusts the inductance of a coil based on the phase difference of high-frequency power to maximize or minimize voltage, ensuring ideal electrical separation between electrodes, reducing mutual interference and allowing for precise power supply adjustments between two power sources connected via matching boxes and waveform detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple electrodes are adjacently disposed in the sample table to enable independent adjustment of treatment characteristics, then treatment uniformity is improved, but mutual interference occurs due to stray capacitance between electrodes
Solution Approach 1:
A coupling circuit is introduced as an intermediary component between adjacent electrodes to control and minimize capacitive coupling. The coupling circuit includes adjustable capacitors that act as mediators to manage the stray capacitance effects, allowing independent electrode operation while reducing mutual interference through controlled coupling paths.
Solution Approach 2:
The capacitance values in the coupling circuits are adjusted as variable parameters to optimize electrode independence. By changing the capacitance parameters in the coupling circuits, the system achieves minimal mutual interference while maintaining the ability to independently control treatment characteristics in different radial regions of the sample table.
2Productivity
If high frequency power is supplied to electrodes to generate bias potential for etching, then etching efficiency is improved, but variations in power distribution cause non-uniform etching rates
Solution Approach 1:
The sample table is divided into multiple radial regions with independently controllable electrodes, allowing local adjustment of power supply parameters. Each electrode can receive customized high frequency power to generate appropriate bias potential for its specific region, enabling uniform etching across the entire sample surface by compensating for local variations in plasma density and temperature.
Solution Approach 2:
The system incorporates feedback mechanisms through coupling circuits that monitor and adjust power distribution to electrodes. By detecting variations in power supply and electrode potential, the feedback system dynamically adjusts capacitance values and power levels to maintain uniform etching rates across different regions of the sample.
3Adaptability or versatility
If the sample table is divided into multiple concentric areas with independent electrode control, then treatment characteristic adjustment is improved, but device complexity increases
Solution Approach 1:
The sample table is segmented into multiple concentric radial regions, each equipped with its own electrode and coupling circuit. This segmentation allows independent control of treatment characteristics in each region while maintaining a modular structure that simplifies the overall system design and facilitates independent adjustment of plasma parameters across different areas of the sample 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 enhances the uniformity and yield of etching treatments by minimizing interference and allowing for accurate power distribution, reducing variations and improving the precision of the etching process.
Implementation Method 1
inductance of a coil is adjusted according to magnitude of a phase difference of high frequency power flowing through a power supply path such that a voltage of the high frequency power becomes a maximum value or a minimum value
Implementation Method 2
a coil is in a connection path that electrically connects, via the coil, positions between each electrode and each matching box on two power supply paths
Implementation Method 3
treating or processing a sample like a semiconductor wafer or substrate placed on an upper surface of a sample table disposed in a treatment chamber in a vacuum container by using plasma generated in the treatment chamber
Implementation Method 4
generating a bias potential above the upper surface of the sample that is placed and held on an upper surface of a sample table by supplying high frequency power to an electrode disposed in the sample table in a treatment chamber, and causing charged particles such as ions in plasma to act on the film layer to be treated on a sample surface with high efficiency
Data Source
AI summary
The present invention provides a plasma processing apparatus and a plasma processing method which improve the uniformity and accordingly the yield in an etching treatment of a sample. In the plasma processing apparatus or the plasma processing method for treating a wafer placed on an upper surface of a sample table disposed in a treatment chamber in a vacuum container by using plasma generated in the treatment chamber, inductance of the coil is adjusted according to magnitude of an phase difference of the high frequency power flowing through the power supply path such that the voltage of the high frequency power becomes a maximum value or a minimum value, in which the coil is in a connection path that electrically connects, via the coil, positions between each electrode and each matching box on a plurality of power supply paths that electrically connect a plurality of electrodes and a plurality of electrodes high frequency power sources which supply high frequency power to the plurality of electrodes disposed at a center part and an area on an outer peripheral side of the center part in the sample table.