EUV Scanner OoB Radiation Measurement and Reduction
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Solution Overview
Problem
Extreme ultraviolet (EUV) scanners generate out-of-band (OoB) EUV radiation that deteriorates the profile of circuit patterns on semiconductor wafers, necessitating a method to evaluate and minimize this radiation to improve lithography performance.
Innovation Solution
A method involving irradiating a first photoresist layer with EUV scanner light, measuring its thickness, and then subtracting the exposure intensity of a second photoresist layer with an OoB EUV light eliminating layer to determine the exposure distribution of OoB EUV radiation, allowing for adjustments to the EUV scanner to minimize OoB EUV radiation and improve pattern uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an EUV scanner is used to generate short wavelengths for improved resolution, then lithography resolution is improved, but out-of-band EUV radiation is generated that deteriorates the profile of circuit patterns
Solution Approach 1:
The patent extracts and removes the harmful out-of-band EUV radiation from the light source using a bandpass filter that transmits only the desired 13.5 nm EUV wavelength while blocking other wavelengths. This separates the useful short-wavelength radiation from the harmful OoB radiation, allowing high-resolution lithography without pattern profile deterioration.
Solution Approach 2:
The patent introduces a bandpass filter as an intermediary component between the EUV light source and the photoresist layer. This mediator selectively transmits the desired 13.5 nm wavelength while blocking out-of-band radiation, thus protecting the photoresist from harmful effects while maintaining the resolution benefits of short-wavelength EUV lithography.
2Manufacturing precision
If the EUV scanner is adjusted to minimize OoB EUV radiation, then pattern profile is improved, but measurement and evaluation of the radiation becomes complex
Solution Approach 1:
The patent creates a simplified measurement system that uses a photo detector to measure the intensity of out-of-band EUV radiation directly. Instead of complex spectral analysis equipment, the system uses a photo detector with known spectral response characteristics to indirectly measure OoB radiation levels, providing a simpler evaluation method that still enables optimization of the bandpass filter performance.
3Object-generated harmful factors
If a bandpass filter is introduced to eliminate OoB EUV light, then OoB radiation is reduced, but the device complexity and number of components increase
Solution Approach 1:
The bandpass filter is designed to perform multiple functions simultaneously: it transmits the desired 13.5 nm EUV wavelength for lithography, blocks out-of-band radiation to protect the photoresist, and its spectral characteristics can be used as a reference for measuring and evaluating the EUV light source performance. This multi-functionality reduces the need for separate measurement and control systems.
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 method enables effective evaluation and reduction of OoB EUV radiation, enhancing the resolution and uniformity of semiconductor device patterns by quantitatively measuring and adjusting the exposure distribution, thereby improving photolithography performance.
Implementation Method 1
lithography technologies using an exposure light having a short wavelength are useful to improve the resolution of a photo lithography
Implementation Method 2
an EUV scanner that minimizes the OoB EUV radiation may be provided or effects of the OoB EUV radiation may be evaluated
Implementation Method 3
measuring thicknesses of the first photoresist pattern, converting the thicknesses of the first photoresist pattern into a first exposure intensity distribution
Data Source
AI summary
A method of manufacturing a semiconductor device includes irradiating a first photoresist layer via a light source, measuring a first exposure intensity of the first photoresist layer, irradiating a second photoresist layer via the light source, measuring a second exposure intensity of the second photoresist layer, subtracting the second exposure intensity from the first exposure intensity, and subsequent to the subtracting, exposing a third photoresist layer formed on a semiconductor substrate by using the light source, wherein an out-of-band (OoB) extreme ultraviolet (EUV) light eliminating layer is formed on the second photoresist layer.