Ultrasonic Probe Sensor Layout for Low-Level Chemical Detection
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Solution Overview
Problem
Existing ultrasonic probes in semiconductor manufacturing are unable to accurately measure small amounts of chemical reagents near or below the lower end of the container, leading to inefficiencies and increased costs due to leftover chemical disposal.
Innovation Solution
An ultrasonic probe design with a plurality of ultrasonic sensors, including an offset configuration and redundant sensing capabilities, allows for precise measurement of liquid levels by emitting sound waves across a conduit and detecting echoes, with improved accuracy near the container bottom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple ultrasonic sensors are positioned in a series along the length of a conduit within the probe, then measurement accuracy is improved, but the ability to accurately measure chemical reagent levels near or below the lower end of the probe deteriorates
Solution Approach 1:
The patent transitions from a single linear array of ultrasonic sensors to a two-dimensional grid arrangement with sensors positioned at multiple heights and radial locations around the conduit. This dimensional expansion allows sensors to be strategically placed to cover the lower measurement zone while maintaining overall measurement accuracy throughout the conduit length.
Solution Approach 2:
The patent implements varying sensor spacing and positioning densities at different locations along the conduit. Closer sensor spacing and additional radial positions are provided near the lower end of the probe where measurement capability was previously insufficient, while standard spacing is used in upper regions. This localized optimization addresses the specific measurement gap without unnecessarily increasing complexity throughout the entire probe.
2Measurement precision
If a greater number of ultrasonic sensors are disposed within the ultrasonic probe, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent designs the sensor grid arrangement so that the same multi-position sensor array serves multiple functions: measuring liquid levels across the entire conduit length, providing enhanced coverage at the lower end, and enabling radial position detection. This multi-functionality justifies the increased sensor count by deriving additional measurement capabilities from the same hardware configuration.
Solution Approach 2:
The patent divides the sensor array into multiple independent sensor units positioned at discrete locations around the conduit. Each sensor can be individually addressed and controlled, allowing the system to process measurements from different zones separately. This segmentation makes the complex array manageable through modular signal processing and enables selective activation of sensor subsets based on measurement needs.
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
Enhances measurement accuracy, reduces residual chemical waste, and optimizes container utilization by detecting the last remaining amounts of chemical reagents, thereby minimizing waste and resource inefficiencies.
Implementation Method 1
A signal processing device (e.g., a controller, meter, personal computer, etc.) transmits electronic signals to the ultrasonic sensors, which in turn generate bursts of sound waves that pass through the conduit and echo back to the sensors.
Implementation Method 2
For each sensor positioned along a particular portion of the conduit, the speed with which the ultrasonic waves travel through the conduit and the intensity of the echoed ultrasonic wave will differ depending on whether that portion of the conduit contains chemical reagent or gas or vapor (i.e., sound travels faster through a liquid medium as compared to gas or vapor).
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An ultrasonic probe having ultrasonic sensors (e.g., piezoelectric crystals) for measuring the level of liquid within a sealed container and having features that make the probe more reliable and enable more precise liquid level readings as the container nears an empty state. Embodiments include spacing the ultrasonic sensors more closely at the lower end of the probe, offsetting the sensors to enable tighter vertical spacing, matched pairs of sensors for redundancy, and a downward facing sensor located at the lower end of the probe to decrease the minimum liquid level that can be accurately measured by the probe. A sump may also be provided to further decrease the minimum liquid level that can be accurately measured by the probe.