Microscope Movable Reflector Module for Phase Image Precision
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Solution Overview
Problem
Current microscope systems for integrated circuit fabrication struggle to accurately predict patterns in resist layers due to limitations in acquiring precise phase images, especially at advanced technology nodes like 20 nm and beyond, where image variation through imaging depth is significant.
Innovation Solution
A microscope apparatus with a movable reflector module and beam splitter configuration that adjusts the optical path length to capture phase images at multiple positions, using polarized light and a Bertrand lens for phase information extraction, allowing for the reconstruction of near-field images for precise latent image prediction on a wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional microscope system is used to acquire intensity images, then the system structure is simple, but the measurement precision of phase images is insufficient for advanced technology nodes
Solution Approach 1:
The optical path is segmented into multiple paths using beam splitters, with one path for reference light and another for sample light. This segmentation enables interferometric measurement by comparing the two paths, thereby achieving high-precision phase imaging while maintaining a modular system structure that can be integrated into existing microscope platforms.
Solution Approach 2:
A movable reflector module acts as an intermediary to adjust the optical path length of the reference beam. By introducing this controllable intermediary element, the system can precisely control the reference path length to match the sample path length, enabling accurate phase measurement without requiring complete redesign of the entire optical system.
2Adaptability or versatility
If the optical path length is fixed, then the device complexity is reduced, but the ability to capture phase images at multiple positions is lost
Solution Approach 1:
The reflector module is designed to be movable along the optical path, transforming a static optical system into a dynamic one. This mobility allows the reference arm optical path length to be adjusted to different positions, enabling the capture of phase images at multiple depths or focal planes, which is critical for three-dimensional phase imaging and advanced technology node characterization.
Solution Approach 2:
The movable reflector module serves multiple functions: it adjusts the reference path length for different imaging depths, compensates for path length differences between sample and reference arms, and enables interferometric measurement. This multi-functionality is achieved through a single adjustable component, minimizing the increase in device complexity while maximizing adaptability.
3Manufacturing precision
If phase information is not accurately captured, then the imaging process is simpler, but the manufacturing precision of predicting latent images is insufficient
Solution Approach 1:
The interferometric setup provides inherent feedback by comparing the reference beam with the sample beam. The interference pattern directly encodes the phase information of the sample, allowing for precise measurement of phase variations. This feedback mechanism enables accurate reconstruction of the latent image by capturing the phase relationship between different optical paths, which is critical for predicting the actual pattern formed in the resist layer.
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 the acquisition of detailed phase images that improve the accuracy of predicting latent images on resist layers, enhancing integrated circuit fabrication by providing precise phase information for advanced technology nodes.
Implementation Method 1
a first beam splitter configured to split the illuminating electromagnetic wave into a first component along a first path and a second component along a second path
Implementation Method 2
a movable reflector module configured to adjust a portion of the second path
Implementation Method 3
a second beam splitter configured to recombine the first component and the second component
Implementation Method 4
A polarizer (polarizing filter) 104 polarizes the (illuminating) light from the source 102
Implementation Method 5
using polarized light and a Bertrand lens for phase information extraction
Data Source
AI summary
A microscope apparatus includes light source configured to generate an illuminating beam. The microscope apparatus further includes a first beam splitter configured to split the illuminating beam into a first component along a first path and a second component along a second path. The microscope apparatus further includes a movable reflector module along the second path. The microscope apparatus further includes a moving mechanism connected to the movable reflector module, wherein the moving mechanism is configured to move the movable reflector in a first direction for adjusting a length of the second path. The microscope apparatus further includes a second beam splitter configured to recombine the first component and the second component. The microscope apparatus further includes an observing device configured to receive the recombined first component and second component.