Reflective Fourier Ptychography Microscopy for Large Surface Inspection

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Solution Overview

Problem

Current inspection systems for large surfaces are inefficient, as they either use expensive cameras with low resolution and large fields of view or high-resolution systems with small fields of view, and are not adaptable to reflective microscopy or scanning large samples effectively.

Innovation Solution

A reflective-mode Fourier ptychography microscopy system that uses a multiple-component light source, collection optics, and a reflected-light sensor to capture images from different angles, computationally reconstructing and overlaying them to achieve high resolution over large areas while reducing artifacts, and employing machine-learning algorithms for defect detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If expensive cameras with large fields of view are used, then the field of view is improved, but the resolution deteriorates

Engineering Contradiction:

Improvefield of viewVSAvoidresolution

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the illumination into multiple angular components using a programmable LED array, where each LED provides illumination from a specific angle. This segmentation allows the system to capture multiple views of the sample and reconstruct high-resolution images computationally, resolving the contradiction between large field of view and high resolution

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from capturing images in a single dimensional space to capturing images in multiple angular dimensions. By illuminating the sample from multiple angles and capturing the reflected light, the system adds angular dimensionality to the imaging process, enabling high-resolution reconstruction across a large field of view

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If high-resolution systems are used, then the resolution is improved, but the field of view deteriorates

Engineering Contradiction:

ImproveresolutionVSAvoidfield of view

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent merges multiple low-resolution images captured from different illumination angles into a single high-resolution image through computational reconstruction. By combining information from multiple angular perspectives, the system achieves high resolution while maintaining a large field of view that would be impossible with a single optical path

Inventive Principle:

Principle #5Merging (Combining)

3Area of stationary object

If transmissive mode Fourier ptychography systems are used, then high magnification with large field of view is achieved, but the system cannot be applied to reflective microscopy or large surface inspection

Engineering Contradiction:

Improvefield of viewVSAvoidadaptability to reflective microscopy

Core Design Contradiction:

Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent inverts the transmissive mode approach by implementing reflective mode Fourier ptychography. Instead of illuminating light through the sample from below, the system illuminates the sample surface from above and captures reflected light, making the technique applicable to opaque surfaces and large-area inspection while maintaining the computational advantages of Fourier ptychography

Inventive Principle:

Principle #13The other way round (Inversion)

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 allows for the inspection of entire surfaces with high resolution in less than 30 minutes, providing a significant increase in efficiency and confidence, detecting defects and material changes across large areas with improved accuracy compared to traditional optics.

Implementation Method 1

collecting radiation redirected from the surface

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

obtaining phase-derivative measurements by differential-phase contrast (DPC) techniques from the radiation collected by the sensor element

Methodology Applied

Scientific EffectDifferential-phase contrast:

Data Source

PatentUS20220413276A1Reflective fourier ptychography imaging of large surfaces

Publication Date: 2022.12.29 LAM RES CORP

AI summary

Various embodiments include reflective-mode Fourier ptychographic microscope (RFPM) apparatuses and methods for using the RFPM. In one example, the RFPM includes a multiple-component light source configured to direct radiation to a surface. The multiple-component light source has a number of individual-light sources, each of which is configured to be activated individually. The RFPM further includes collection optics to receive radiation reflected and scattered or otherwise redirected from the surface, and a sensor element to convert received light-energy from the collection optics into an electrical-signal output. Other apparatuses, designs, and methods are disclosed.