Integrated Illumination And Detection Optics for Compact Metrology
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Solution Overview
Problem
Existing metrology tools, such as scatterometers, have complex and expensive illumination and detection systems due to separate optical branches, which are not compact and unreliable.
Innovation Solution
An illumination and detection arrangement with a plurality of individually configurable illumination sources and image sensors in a common plane, integrated with an objective lens, allowing for flexible illumination and detection of scattered radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate optical branches are used for illumination and detection, then measurement precision can be maintained, but device complexity increases and reliability decreases
Solution Approach 1:
The patent combines separate illumination and detection optical branches into a single integrated optical system. The illumination source, objective lens, and detector are merged into one compact arrangement where the same objective lens is used for both illuminating the specimen and collecting scattered light, eliminating the need for separate optical paths and reducing overall system complexity.
Solution Approach 2:
The objective lens serves multiple functions: it acts as both the illumination objective for directing light onto the specimen and the detection objective for collecting scattered radiation. This multi-functional design reduces the number of components needed while maintaining measurement capabilities.
2Measurement precision
If separate optical branches are used for illumination and detection, then measurement precision can be maintained, but reliability decreases
Solution Approach 1:
By merging separate optical branches into a single integrated system with fewer components and alignment points, the patent reduces potential failure points and improves system reliability. The simplified architecture eliminates interfaces between separate illumination and detection paths that could introduce errors or failures.
3Device complexity
If integrated illumination and detection arrangement is used, then device complexity is reduced, but illumination intensity may be affected
Solution Approach 1:
The patent employs individually configurable illumination sources positioned at specific locations in the illumination plane, allowing optimization of illumination intensity and distribution at the specimen plane. Each illumination source can be independently controlled to provide appropriate intensity for the specific measurement requirements.
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 integration reduces the complexity and cost of metrology tools while improving their reliability and performance by enabling compact, efficient, and adaptable measurement systems.
Implementation Method 1
an objective lens defining an objective NA area and configured to receive the illumination radiation, focus it onto a structure in an object plane, and subsequently collect radiation scattered from the structure upon illumination
Implementation Method 2
an objective lens defining an objective NA area and configured to receive the illumination radiation, focus it onto a structure in an object plane
Implementation Method 3
at least one image sensor located in a detection plane and configured to detect at least one portion of the scattered radiation collected by the objective lens and record an image associated with the structure
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~5(e)
AI summary
Disclosed is an illumination and detection arrangement for a lithographic or inspection apparatus, comprising: a plurality of individually configurable illumination sources located in an illumination plane, each being operable to emit illumination radiation; an objective lens defining an objective NA area and configured to receive the illumination radiation, focus it onto a structure in an object plane, and subsequently collect radiation scattered from the structure upon illumination; and at least one image sensor located in a detection plane and configured to detect at least one portion of the scattered radiation collected by the objective lens and record an image associated with the structure; wherein the at least one portion of the scattered radiation either is detected at or passes through the illumination plane.