Wafer Inspection Optics With Switchable Numerical Aperture
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Solution Overview
Problem
Existing inspection apparatuses face challenges with fixed numerical apertures of collimated light, leading to diffraction issues that reduce image and device resolution, especially with smaller chip sizes and complex patterns.
Innovation Solution
An inspection apparatus with a numerical aperture adjustment device using a rotatable lens turret and optical members to dynamically adjust the numerical aperture, preventing diffraction by manually or automatically selecting optical members with different apertures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed numerical aperture is used in the illumination unit, then the device structure is simple, but diffraction phenomenon occurs reducing image and device resolution
Solution Approach 1:
The illumination unit is designed with a rotatable lens turret that allows dynamic switching between multiple optical members with different numerical apertures. This dynamic configuration enables the system to adapt the numerical aperture based on inspection requirements, preventing diffraction phenomena while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The system changes the numerical aperture parameter by replacing or rotating optical members with different fixed numerical aperture values. This parameter adjustment allows optimization of light illumination for different inspection scenarios, resolving the diffraction issue without requiring continuous variable adjustment mechanisms, thus balancing precision improvement with structural simplicity.
2Manufacturing precision
If collimated light with fixed numerical aperture is used, then the illumination system is simple to operate, but resolution deteriorates when chip size decreases or patterns become complex
Solution Approach 1:
The illumination unit incorporates multiple optical members with different numerical apertures in a rotatable turret, enabling a single device to serve multiple inspection scenarios. The system can universally handle different chip sizes and pattern complexities by selecting the appropriate optical member, thereby improving both image resolution and adaptability simultaneously.
Solution Approach 2:
The rotatable lens turret provides dynamic reconfiguration capability, allowing the system to adapt to different inspection requirements in real-time. This dynamic adaptability ensures optimal performance across various chip sizes and pattern complexities without requiring multiple separate illumination systems.
3Manufacturing precision
If multiple optical members with different numerical apertures are installed, then diffraction phenomenon is reduced and resolution is improved, but the device complexity increases
Solution Approach 1:
The system uses a rotatable lens turret mechanism that provides dynamic switching between multiple optical members. This dynamic design allows multiple numerical aperture options to be integrated in a compact, manageable structure, reducing the practical complexity increase despite having multiple optical components.
Solution Approach 2:
The illumination system is segmented into multiple discrete optical members, each optimized for specific numerical aperture requirements. This segmentation allows independent optimization of each component while maintaining overall system manageability through the modular turret structure, balancing resolution improvement with operational simplicity.
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 effectively prevents diffraction, enhances image resolution, and improves device resolution, applicable to various wafer sizes and complex patterns.
Implementation Method 1
a first optical member having a first numerical aperture that is replaceable with a second optical member having a second numerical aperture different from the first numerical aperture so as to reduce a diffraction phenomenon caused by the illuminating light
Implementation Method 2
reduce a diffraction phenomenon caused by the illuminating light
Data Source
AI summary
The present invention relates to an inspection apparatus and an inspection method which selectively adjust a numerical aperture of illuminating light in the form of collimated light when inspecting a target object, such as a wafer or the like, using a spectrum, thereby preventing a diffraction phenomenon caused by the illuminating light. The inspection apparatus may include: a camera unit disposed above a target object; an illumination unit configured to illuminate the target object with illuminating light; and a light detection unit configured to detect reflection light of the target object illuminated with the illuminating light, wherein the illumination unit comprises a numerical aperture adjustment device which has a first optical member having a first numerical aperture that is replaceable with a second optical member having a second numerical aperture different from the first numerical aperture so as to reduce a diffraction phenomenon caused by the illuminating light.