Substrate-Level Radiation Sensor for High NA Lithography
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Solution Overview
Problem
Conventional lithographic apparatus sensors are not optimized for high numerical aperture (NA) systems, leading to inefficiencies in imaging performance due to issues like partial and total internal reflections and absorption, which reduce radiation intensity and image resolution.
Innovation Solution
A substrate-level sensor is designed with a radiation receiver, a transmissive plate supporting the receiver, a quantum conversion layer that absorbs light at one wavelength and reradiates it at another, and a fiber optics block to guide the reradiated light to a radiation detector, positioned in close proximity to minimize light losses and maintain image resolution in high NA systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional sensor is used in a high NA system, then the device complexity is reduced, but the measurement precision deteriorates due to partial and total internal reflections and absorption
Solution Approach 1:
A quantum conversion layer is introduced as an intermediary between the transmissive plate and the radiation detector. This layer converts radiation at the first wavelength (which suffers from internal reflections and absorption in high NA systems) to radiation at a second wavelength that can be detected with higher precision. The quantum conversion layer acts as a mediator that transforms the problematic radiation into detectable signals, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The invention changes the wavelength parameter of the radiation by using a quantum conversion layer that converts radiation from a first wavelength to a second wavelength. This parameter change allows the system to overcome the limitations of partial and total internal reflections and absorption that occur at the original wavelength, thereby improving measurement precision without requiring a complete redesign of the sensor structure.
2Reliability
If the radiation detector is positioned away from the quantum conversion layer, then the device complexity is reduced, but the sensitivity deteriorates due to light losses
Solution Approach 1:
The radiation detector is positioned in close proximity to and integrated with the quantum conversion layer, essentially nesting the detector within the optical path immediately adjacent to the conversion layer. This nested arrangement minimizes the distance over which converted light must travel, reducing light losses and maximizing sensitivity. The close integration of these components resolves the contradiction by embedding the detector within the critical optical path rather than positioning it separately.
3Ease of manufacture
If a transmissive plate is used to support the radiation receiver, then the ease of manufacture is improved, but the loss of energy increases due to absorption
Solution Approach 1:
The quantum conversion layer changes the wavelength parameter of the incident radiation to a second wavelength at which the transmissive plate has lower absorption. By converting the radiation before it passes through the transmissive plate, the system reduces energy loss due to absorption while maintaining the manufacturing simplicity of using a transmissive plate structure.
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
The solution enhances sensitivity and maintains image resolution in high NA systems by reducing light losses and thermal disturbances, improving the measurement of lens aberrations and overall imaging performance.
Implementation Method 1
a quantum conversion layer arranged to absorb light at a first wavelength incident on the transmissive plate and reradiate light at a second wavelength
Implementation Method 2
a fiber optics block comprising a plurality of optical fibers and a radiation detector, wherein the plurality of optical fibers is arranged to guide light reradiated by the quantum conversion layer towards the radiation detector
Data Source
AI summary
A radiation sensor includes a radiation receiver positioned in a focal plane of the final element of the projection system; a transmissive plate supporting the radiation receiver at a side facing the projection system; a quantum conversion layer to absorb light at the first wavelength incident on the transmissive plate and reradiate light at a second wavelength; a fiber optics block with a plurality of optical fibers; and a radiation detector. In the radiation sensor, the plurality of optical fibers guide light is reradiated by the quantum conversion layer towards the radiation detector. The radiation sensor can be used as a substrate-level sensor in a lithographic apparatus.