Dummy Wafer Sensor Alignment for Electrostatic Chuck Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wafer alignment technologies are complex and expensive, requiring precise positioning and optical systems, making them unsuitable for ultra-thin sensing applications and necessitating frequent recalibration, which increases system complexity and costs.
Innovation Solution
A wafer-type sensor system comprising a dummy wafer with integrated sensor modules and a processor that measures distances between the dummy wafer and an electrostatic chuck, allowing for precise alignment and transfer control, along with a calibration device to maintain consistent light intensities across multiple sensor modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an image sensor-based alignment system is used, then alignment precision can be achieved, but the system complexity increases and it becomes unsuitable for ultra-thin sensing systems
Solution Approach 1:
The patent extracts only the essential sensing function from complex image sensor systems. By using a simple distance sensor to measure only the gap distance between the dummy wafer and electrostatic chuck, the system achieves alignment capability without the unnecessary complexity of image sensors, optical systems, and lighting requirements.
Solution Approach 2:
The patent replaces the optical-based image sensor system with a mechanical/electrical distance sensing approach. The distance sensor directly measures the physical gap distance, substituting the complex optical path, lenses, and image processing with a simpler direct measurement mechanism suitable for ultra-thin applications.
2Measurement precision
If an alignment system with image sensor and optical system is added, then alignment capability is provided, but expensive semiconductor equipment/transfer system changes are required
Solution Approach 1:
The patent uses a cost-effective dummy wafer with integrated distance sensor instead of expensive alignment systems. The dummy wafer serves as a temporary, disposable alignment tool that provides necessary measurement capability without requiring costly modifications to semiconductor equipment or transfer systems.
Solution Approach 2:
The dummy wafer itself provides the alignment measurement function through its integrated distance sensor. Rather than requiring external alignment equipment, the dummy wafer performs self-measurement of the gap distance, eliminating the need for separate alignment systems and reducing overall equipment costs.
3Measurement precision
If multiple sensor modules are provided for comprehensive measurement, then measurement coverage is improved, but calibration complexity increases
Solution Approach 1:
The patent uses parameter changes (light intensity adjustment) as a calibration mechanism. By adjusting the light intensity parameter of the light source, the system can calibrate multiple sensor modules to achieve consistent measurements, simplifying the calibration process compared to complex mechanical or electrical adjustment mechanisms.
Solution Approach 2:
The patent implements a feedback-based calibration process where the light source intensity is adjusted based on feedback from the sensor modules. This closed-loop approach allows automatic calibration of multiple sensors, reducing calibration complexity while maintaining comprehensive measurement coverage.
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 precise and cost-effective wafer alignment with reduced system complexity, suitable for ultra-thin sensing systems, and maintains consistent performance across various environments through automatic calibration.
Implementation Method 1
a light source configured to emit light to the ring, and a light receiver configured to detect light reflected from the ring
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A wafer-type sensor for wafer alignment includes a dummy wafer; a sensor module disposed in the dummy wafer, and a processor configured to control the sensor module to measure a distance between a side surface of the dummy wafer and a ring formed around a periphery of an electrostatic chuck based on the dummy wafer being mounted on the electrostatic chuck by a transfer robot.