Optical Plasma Sensor Apparatus for Non-Invasive Ion Flux Measurement
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Solution Overview
Problem
Current methods for measuring electrical parameters in plasma processing systems, such as ion flux and ion energy, are challenging due to their complex and nonlinear nature, leading to non-uniform and unstable plasma conditions, and existing sensors are often intrusive, costly, or lack spatial resolution.
Innovation Solution
A sensor apparatus comprising multiple sensors, including capacitive, inductive, and optical emission sensors, designed to measure plasma parameters with minimal perturbation, providing spatially resolved and non-invasive data through a combination of sensing elements and transducers that convert signals into measurable forms for processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensors (biased probes, wall probes) are used to measure ion flux and ion energy, then measurement capability is provided, but the sensors excessively modify or interact with the local plasma state (intrusive measurement)
Solution Approach 1:
The patent uses an optical intermediary (laser beam) to measure plasma parameters without direct physical contact. The laser passes through the plasma and its properties (absorption, scattering, refractive index) are modified by the plasma, providing measurement data without the sensor itself disturbing the plasma state. This resolves the contradiction by mediating between the measurement need and plasma preservation.
Solution Approach 2:
The patent replaces mechanical/electrical sensors (probes that physically contact or come close to plasma) with optical measurement methods. By using light interaction with plasma (absorption spectroscopy, scattering, interferometry), the system achieves measurement without mechanical intrusion, eliminating the harmful plasma modification caused by traditional sensors.
2Device complexity
If aggregate measurement methods are used, then simplicity is maintained, but spatial resolution is lacking
Solution Approach 1:
The patent segments the plasma measurement into multiple spatial locations by using multiple laser beams or scanning a single laser across different positions. Each measurement point provides localized data, and combining these segmented measurements creates a comprehensive spatial map of plasma parameters, achieving both simplicity and spatial resolution.
Solution Approach 2:
The patent adds spatial dimensionality to measurements by using laser sheet technology or confocal arrangements that provide depth resolution. This transforms single-point measurements into three-dimensional plasma characterization, maintaining optical simplicity while achieving high spatial resolution through dimensional expansion.
3Measurement precision
If complex sensor systems are used to achieve accurate plasma parameter measurement, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent employs a universal optical platform (laser system with detectors) that can measure multiple plasma parameters (density, temperature, flow velocity, composition) using the same basic hardware. By adjusting measurement wavelengths and analysis methods rather than hardware configuration, the system achieves multi-parameter capability with single-function simplicity.
Solution Approach 2:
The patent achieves different measurement capabilities by changing optical parameters (wavelength, pulse duration, power level) rather than hardware complexity. A single laser system can operate in continuous wave mode for density measurement or pulsed mode for temperature measurement, providing versatile plasma diagnostics through parameter adjustment rather than system complexity.
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
Enables accurate, cost-effective monitoring and optimization of plasma processes by providing detailed, spatially resolved measurements of plasma parameters, improving process control and efficiency in semiconductor and flat panel display manufacturing.
Implementation Method 1
capacitive sensors
Implementation Method 2
inductive sensors
Implementation Method 3
optical emission sensors
Data Source
AI summary
A sensor apparatus for measuring a plasma process parameter for processing a workpiece. The sensor apparatus includes a base, an information processor supported on or in the base, and at least one sensor supported on or in the base. The at least one sensor includes at least one sensing element configured for measuring an electrical property of a plasma and may include a transducer coupled to the at least one sensing element. The transducer can be configured to receive a signal from the sensing element and convert the signal into a second signal for input to the information processor.