High-Harmonic Radiation Source for EUV Beam Metrology
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Solution Overview
Problem
Existing metrology tools struggle to accurately measure small features in integrated circuits due to the lack of suitable radiation sources for high harmonic generation, leading to inaccurate and time-consuming measurements.
Innovation Solution
A beam metrology device that generates and measures high harmonic radiation through nonlinear processes, allowing for precise characterization of radiation characteristics and controlling the radiation source to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visible or near-infrared radiation is used for metrology measurements, then the measurement can be performed with current technology, but the pitch of the grating must be much coarser than the actual product structures, resulting in inaccurate measurements
Solution Approach 1:
The patent changes the wavelength parameter of the radiation used for metrology measurements from visible/near-infrared to extreme ultraviolet (EUV) range (e.g., 13.5 nm). This parameter change enables the radiation wavelength to be comparable to or smaller than the product structure dimensions, allowing direct and accurate measurement of fine features without requiring coarser grating pitches.
2Measurement precision
If extreme ultraviolet radiation with wavelength comparable to product structures is used, then direct and accurate measurement of small features is enabled, but such wavelengths are not normally available or usable for metrology
Solution Approach 1:
The patent introduces an intermediary approach by using a scatterometer configuration where EUV radiation interacts with the sample structure to produce scattered radiation patterns. The scattering process itself acts as an intermediary mechanism that converts the interaction information into measurable diffraction patterns, enabling the use of EUV wavelengths for metrology without requiring direct imaging capabilities at those wavelengths.
3Manufacturing precision
If scattering-based metrology methods are used, then overlay measurements can be performed on smaller targets surrounded by product structures, but the known scatterometers use visible or near-infrared light requiring much coarser grating pitch
Solution Approach 1:
The patent changes the radiation wavelength parameter from visible/near-infrared to EUV range, which fundamentally alters the interaction between radiation and the target structures. This enables the scatterometer to measure much smaller targets with finer pitch structures, as the EUV wavelength is comparable to the dimensions of modern semiconductor features, allowing accurate overlay measurements on production-like targets.
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
Enables high-resolution, efficient measurement of small features in integrated circuits by utilizing high harmonic generation radiation, providing accurate and timely feedback for process control.
Implementation Method 1
a source nonlinear medium configured to generate the second radiation via the first nonlinear process upon receiving the first portion of first radiation
Implementation Method 2
a metrology device nonlinear medium configured to receive a second portion of the first radiation and thereby to generate third radiation via a second nonlinear process
Data Source
AI summary
A beam metrology device for determining at least one characteristic of first radiation and/or at least one characteristic of second radiation, said second radiation being generated via a first nonlinear process upon receiving a first portion of the first radiation; the beam metrology device comprising: a metrology device nonlinear medium configured to receive a second portion of the first radiation and thereby to generate third radiation via a second nonlinear process; at least one detector configured to measure at least one characteristic of the third radiation; and a processing unit operable to determine the at least one characteristic of the first radiation and/or the at least one characteristic of the second radiation based on said at least one characteristic of the third radiation.