Multispectral Nanostructure Critical Dimension Measurement
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Solution Overview
Problem
Current methods for measuring critical dimensions of nanostructures, particularly in semiconductor chips, face challenges in achieving accurate, reliable, and cost-effective measurements as dimensions approach 10 nm, requiring advanced and precise techniques to support mass production.
Innovation Solution
A multispectral imaging method and device that utilize a broad frequency spectrum to acquire and compare intensity distribution arrays of nanostructures, employing a calibrated reference object and numerical methods like Maxwell's equations to determine critical dimensions, incorporating a spectrum selection unit and image sensors for precise data collection and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used for nanostructures, then measurement process is simple, but measurement precision and reliability deteriorate as dimensions approach 10 nm
Solution Approach 1:
The patent transitions from conventional single-wavelength optical measurement to multispectral imaging across multiple wavelengths (380-740 nm). This dimensional expansion in spectral space enables differentiation of scattering signals at 10 nm critical dimensions, achieving measurement precision that conventional methods cannot provide while managing system complexity through modular spectral filtering components
Solution Approach 2:
The patent varies multiple parameters simultaneously: wavelength (380-740 nm range), polarization state, and focal position along the optical axis. By changing these parameters and analyzing the resulting intensity distribution arrays (i*j*m*n dimensions), the system achieves reliable critical dimension measurement at 10 nm scale, transforming a precision problem into a multi-parameter characterization solution
2Reliability
If measurement accuracy is improved for 10 nm structures, then reliability increases, but measurement time and cost increase
Solution Approach 1:
The patent pre-calculates scattering intensity distributions for various critical dimension values using rigorous coupled wave analysis (RCWA) and stores them as reference libraries before measurement. During actual measurement, the experimental intensity distribution array is directly compared against this pre-computed library, enabling rapid reliable determination of critical dimensions at 10 nm without time-consuming iterative calculations
Solution Approach 2:
The patent replaces sequential mechanical scanning and single-wavelength measurement with parallel multispectral imaging using broadband light sources and spectral filtering. This substitution captures complete scattering information across all wavelengths simultaneously, achieving high reliability measurements in a single exposure rather than through time-consuming sequential scans
3Measurement precision
If conventional optical methods are used, then device complexity is low, but measurement precision deteriorates at nanoscale dimensions
Solution Approach 1:
The patent segments the broadband spectrum into multiple discrete wavelength bands using spectral filtering (bandpass filters or monochromator). Each spectral band provides independent scattering information that is captured and processed separately. This segmentation of the spectral domain enables precise critical dimension measurement at 10 nm by analyzing wavelength-dependent scattering characteristics while keeping the optical system architecture manageable through modular filter components
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 efficient, accurate, and cost-effective measurement of nanostructure critical dimensions, supporting the production of semiconductor structures with dimensions as low as 10 nm by leveraging multispectral imaging and advanced data processing techniques.
Implementation Method 1
an optical radiation source emitting light with a broad spectrum
Implementation Method 2
collecting light scattered by the object under investigation
Data Source
AI summary
Provided are a method and device for measuring a critical dimension of a nanostructure. The method includes acquiring a reference intensity distribution, in each of a number of spectral bands, of light scattered by at least one reference nanostructure, for each of a number at different positions of the at least one reference nano structure disposed along an optical axis; generating a library of reference intensity distribution arrays based on a number of the reference intensity distributions, determining an intensity distribution of light scattered by a nanostructure under investigation, for each of the number of spectral bands, at each of the number of different positions of the nanostructure under investigation disposed along the optical axis; generating an intensity distribution array by using the determined intensity distributions, and determining information about a critical dimension of the nanostructure under investigation by comparing the intensity distribution array with the library of reference intensity distribution arrays.