Sonar Wafer Detection in Processing Chambers for Transparent Substrates
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Solution Overview
Problem
Existing detection equipment, such as light source detectors, are ineffective for transparent wafers in semiconductor fabrication due to low reflectivity, leading to reduced reliability in processing steps like wafer presence detection and alignment.
Innovation Solution
Employing a sonar sensor with an emitter and detector to utilize sound waves for detecting the presence and alignment of wafers, including transparent ones, by measuring sonar intensity values to determine distances and verify wafer presence and alignment marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light source detectors are used to detect wafer presence and alignment, then the detection system is simple and easy to operate, but transparent wafers cannot be detected accurately due to low reflectivity
Solution Approach 1:
The patent replaces the optical detection system (light source detector) with an acoustic detection system (sonar sensor). The sonar sensor emits sound waves that reflect off the wafer surface, and the reflected sound waves are detected to determine wafer presence, alignment marks, and thickness. This acoustic approach works effectively for transparent wafers that are invisible to optical detectors.
Solution Approach 2:
The patent changes the detection parameter from optical reflectivity to acoustic reflection. By using sound waves instead of light waves, the system can detect transparent wafers that have low optical reflectivity but sufficient acoustic reflection properties, thereby improving detection reliability for transparent materials.
2Measurement precision
If sonar sensor is used to detect transparent wafers, then detection precision for transparent wafers is improved, but device complexity increases
Solution Approach 1:
The patent replaces the optical detection system (light source detector) with an acoustic detection system (sonar sensor). The sonar sensor emits sound waves that reflect off the wafer surface, and the reflected sound waves are detected to determine wafer presence, alignment marks, and thickness. This acoustic approach works effectively for transparent wafers that are invisible to optical detectors.
Solution Approach 2:
The sonar sensor performs multiple detection functions including wafer presence detection, alignment mark location, and wafer thickness measurement. This multi-functionality reduces the need for multiple separate detection systems, thereby limiting the increase in overall device complexity while improving measurement precision for transparent wafers.
3Device complexity
If light source detectors are used, then the detection system is simple in structure, but it fails to provide accurate detection for transparent materials
Solution Approach 1:
The patent replaces the optical detection system (light source detector) with an acoustic detection system (sonar sensor). The sonar sensor emits sound waves that reflect off the wafer surface, and the reflected sound waves are detected to determine wafer presence, alignment marks, and thickness. This acoustic approach works effectively for transparent wafers that are invisible to optical detectors.
Solution Approach 2:
The patent changes the detection parameter from optical reflectivity to acoustic reflection. By using sound waves instead of light waves, the system can detect transparent wafers that have low optical reflectivity but sufficient acoustic reflection properties, thereby improving detection reliability for transparent materials.
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 the reliability of semiconductor processing by accurately detecting transparent wafers and alignment marks, improving the precision and efficiency of processing steps regardless of wafer material transparency.
Implementation Method 1
The sonar sensor includes an emitter configured to emit sound waves towards the workpiece holder apparatus and a detector configured to receive reflected sound waves
Implementation Method 2
sonar sensor control circuitry coupled to the sonar sensor and configured to determine if the workpiece is present on the workpiece holder apparatus based on a sonar intensity value of the reflected sound waves received by the detector of the sonar sensor
Data Source
AI summary
In some embodiments, the present disclosure relates a process tool that includes a chamber housing defining a processing chamber. Within the processing chamber is a workpiece holder apparatus that is configured to hold a workpiece. A sonar sensor is arranged over the workpiece holder apparatus. The sonar sensor includes an emitter that is configured to produce sound waves traveling towards the workpiece holder apparatus. The sonar sensor also includes a detector that is configured to receive reflected sound waves from the workpiece holder apparatus or an object between the sonar sensor and the workpiece holder apparatus. Further, sonar sensor control circuitry is coupled to the sonar sensor and is configured to determine if a workpiece is present on the workpiece holder apparatus based on a sonar intensity value of the reflected sound waves received by the detector of the sonar sensor.