Electrically Controllable Aperture for Semiconductor Inspection Sensors
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Solution Overview
Problem
Conventional semiconductor inspection and metrology tools face challenges in quickly and reliably adjusting the size of each pixel's light-sensitive region due to mechanical apertures, which occupy significant space and slow down inspections, especially when multiple apertures are required for different wavelengths and angles of light illumination.
Innovation Solution
The implementation of an electrically controlled pixel aperture size in linear sensors using a non-monotonic voltage profile, generated by centrally located aperture control electrodes, allows for adjustable effective light-sensitive regions, enabling precise control of photoelectron collection without mechanical motion, thereby optimizing light collection and inspection speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical apertures are used to adjust the light-sensitive region size, then the aperture can be precisely positioned, but the inspection speed decreases and the device occupies significant space
Solution Approach 1:
The patent replaces mechanical aperture systems with an electrical control mechanism using a resistive gate and voltage profile generation. The effective aperture size is controlled by applying different voltages to segments of the resistive gate, creating electric fields that deflect photoelectrons from specific regions of the light-sensitive area. This eliminates mechanical moving parts, reduces space requirements, and enables rapid aperture size changes without mechanical inertia or wear.
Solution Approach 2:
The patent changes the electrical parameters (voltage levels and distribution) of the resistive gate to dynamically adjust the effective aperture size. By varying the voltage profile along the resistive gate, the system can electrically reconfigure which portions of the light-sensitive region are active, enabling fast switching between different aperture sizes without physical movement.
2Adaptability or versatility
If multiple mechanical apertures are used for different wavelengths and angles of light illumination, then the system can handle diverse materials and structures, but the device complexity and space requirements increase
Solution Approach 1:
The patent implements a single resistive gate structure that can be electrically configured to perform multiple functions corresponding to different aperture sizes and configurations. By programming different voltage profiles on the same resistive gate, the system can adapt to inspect different materials and structures with varying reflectivities, eliminating the need for multiple physical apertures and reducing overall device complexity.
Solution Approach 2:
The patent introduces dynamic electrical control of the aperture configuration through the resistive gate voltage profile. This allows the system to rapidly switch between different aperture settings during operation, providing adaptability for different inspection scenarios without requiring multiple static mechanical apertures. The dynamic reconfiguration capability enables the same hardware to serve multiple inspection purposes.
3Adaptability or versatility
If mechanical apertures are switched for different inspection configurations, then the correct aperture can be selected for each task, but the switching time slows down the inspection process
Solution Approach 1:
The patent replaces mechanical aperture switching with electrical voltage profile switching on the resistive gate. Since electrical signals can be changed instantaneously compared to mechanical movement, the system can switch between different aperture configurations without the time delay associated with mechanical actuation, thereby maintaining adaptability while eliminating switching time losses.
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 solution allows for high-speed inspection and measurement by dynamically adjusting the aperture size of each pixel, enhancing the flexibility and precision of semiconductor inspection systems, particularly in handling small features and diverse materials, while reducing the need for mechanical adjustments and space constraints.
Implementation Method 1
control voltages respectively applied by way of end electrodes to opposing end portions of each pixel's resistive control gate produce an associated electric field in the pixel's light sensitive region
Implementation Method 2
photoelectrons generated by incident light entering the pixel's light sensitive region
Data Source
AI summary
Pixel aperture size adjustment in a linear sensor is achieved by applying more negative control voltages to central regions of the pixel's resistive control gate, and applying more positive control voltages to the gate's end portions. These control voltages cause the resistive control gate to generate an electric field that drives photoelectrons generated in a selected portion of the pixel's light sensitive region into a charge accumulation region for subsequent measurement, and drives photoelectrons generated in other portions of the pixel's light sensitive region away from the charge accumulation region for subsequent discard or simultaneous readout. A system utilizes optics to direct light received at different angles or locations from a sample into corresponding different portions of each pixel's light sensitive region. Multiple aperture control electrodes are selectively actuated to collect/measure light received from either narrow or wide ranges of angles or locations, thereby enabling rapid image data adjustment.