TDI Sensor Variable Voltage Clocks for Vacuum Imaging
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Solution Overview
Problem
Current TDI imaging systems struggle to utilize light sources with wavelengths below 100 nm due to ionization of gas particles, which prevents suitable imaging, and modifying these systems to operate in a vacuum chamber to avoid ionization leads to heat damage from higher energy light sources.
Innovation Solution
The use of variable amplitude readout clock signals in TDI sensors, where amplitudes increase progressively along the pixel column to minimize power consumption and heat generation, allowing for the use of ultra-high frequency light in next-generation semiconductor inspection and metrology systems, even in vacuum chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If TDI imaging systems operate in a vacuum chamber to avoid gas particle ionization by ultra-high frequency light, then imaging capability at wavelengths below 100 nm is enabled, but heat damage to the sensor occurs due to higher energy light sources
Solution Approach 1:
The patent applies parameter changes by varying the amplitude of readout clock signals according to the vertical position of pixel rows. Upper pixel rows receive clock signals with lower amplitudes while lower pixel rows receive clock signals with higher amplitudes, optimizing power consumption at each position and reducing overall heat generation in the vacuum chamber environment
2Ease of operation
If constant amplitude readout clock signals are used in TDI sensors, then simple control is maintained, but power consumption and heat generation are excessive
Solution Approach 1:
The patent implements local quality by assigning different clock signal amplitudes to different regions (pixel rows) based on their specific requirements. Each pixel row receives clock signals with amplitudes optimized for its position in the TDI array, reducing overall power consumption while maintaining operational simplicity through automated amplitude assignment
Solution Approach 2:
The system transitions from static constant amplitude clock signals to dynamic variable amplitude clock signals that automatically adjust based on pixel row position, enabling optimized power consumption across the sensor array without complex manual control
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 reduces sensor power consumption by approximately one-third, minimizing heat generation and enabling the use of existing TDI sensors in next-generation systems for imaging with wavelengths below 100 nm without ionization issues.
Implementation Method 1
The reflected light is projected/guided onto the sensor, causing the sensor to generate photoelectrons in the pixels that form image charges representing the amount of received reflected light
Data Source
AI summary
A Time Delay and Integration (TDI) imaging system utilizing variable voltage readout clock signals having progressively increasing amplitudes defined as a function of pixel row location, where pixel rows positioned to receive/collect/transfer image-related charges at the start of the TDI imaging process are controlled using lower amplitude readout clock signals than pixel rows positioned to receive/collect/transfer image-related charges near the end of the TDI process. The clock signal amplitude for each pixel row is determined by the expected maximum amplitude needed to hold and transfer image charges by the pixels of that row. Multiple (e.g., three) primary phase signals are generated that are passed through splitters to provide multiple identical secondary phase signals, and then drivers having gain control circuitry are utilized to produce voltage readout clock signals having the same phases as the primary phase signals, but having two or more different voltage amplitudes.