Transparent Article Inspection Using UV Light
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Solution Overview
Problem
Current inspection methods using visible light lasers fail to detect optical inhomogeneities in transparent substrates and optical components, leading to transfer pattern defects during photolithography with high-energy exposure lights like ArF and F2 excimer lasers, resulting in degraded transfer precision.
Innovation Solution
An inspection method utilizing light with a wavelength of 200 nm or shorter is introduced into transparent articles, and light with a longer wavelength than the inspection light is detected to identify regional or local optical inhomogeneities, ensuring accurate detection of defects that affect pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visible light laser inspection is used, then the inspection device is simple and easy to operate, but optical inhomogeneities such as interior defects cannot be detected accurately
Solution Approach 1:
The patent changes the wavelength parameter of the inspection light from visible light to ultraviolet light (200 nm or shorter). This parameter change enables the detection of optical inhomogeneities that are invisible to visible light, allowing accurate identification of interior defects while maintaining a relatively simple inspection device structure.
2Manufacturing precision
If high-energy exposure light is used for pattern transfer, then transfer precision can be achieved, but optical inhomogeneities cause regional changes in optical properties leading to transfer pattern defects
Solution Approach 1:
The patent performs inspection using ultraviolet light before the high-energy exposure process. By detecting optical inhomogeneities in advance, the method prevents regional optical property changes from causing transfer pattern defects, ensuring both high transfer precision and reliable pattern quality.
3Measurement precision
If ultraviolet light with wavelength of 200 nm or shorter is used for inspection, then optical inhomogeneities can be detected accurately, but surface damage and plasma generation may occur
Solution Approach 1:
The patent uses ultraviolet light with wavelength of 200 nm or shorter for inspection, which is sufficient to detect optical inhomogeneities accurately. By using the minimum necessary energy level that achieves detection accuracy, the method avoids excessive energy input that would cause surface damage and plasma generation.
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 enables precise detection of interior defects in transparent substrates and optical components, preventing transfer pattern defects and ensuring high transfer precision by identifying and addressing optical inhomogeneities before pattern transfer, while minimizing surface damage and plasma generation.
Implementation Method 1
light having a wavelength longer than that of the inspection light that is generated regionally or locally is detected on the optical path over which the inspection light is propagated within the transparent article
Data Source
AI summary
An inspection method of transparent articles wherein presence or absence of optical inhomogeneities within the transparent articles can be accurately inspected is provided.In an inspection method of transparent articles used in photolithography, for inspecting whether or not there are inhomogeneities within transparent articles (4) formed of transparent material wherein optical properties regionally or locally change with regard to exposure light (specifically, interior defects 16), inspection light having a wavelength of 200 nm or shorter is introduced to the transparent article, and light (15) having a longer wavelength than the inspection light which is regionally or locally emitted is sensed on the optical path over which the inspection light is propagated within the transparent article, thereby detecting presence or absence of optical inhomogeneities within the transparent article.