X-Ray Scatterometry Signal Filtering for Patterned Structure Metrology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
X-ray scatterometry measurements on patterned structures are hindered by roughness and background noise, which significantly affect the interpretation of dimensional characteristics due to the small wavelength of X-rays, leading to substantial errors in data interpretation.
Innovation Solution
A method that processes measured signals by identifying and separating diffraction orders from background noise, using an optimized measurement scheme with specific angular and azimuthal orientations of incident radiation to isolate and subtract background contributions, resulting in clean images for accurate parameter determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-ray scatterometry is used for dimensional characterization, then measurement precision is improved, but background noise and roughness effects worsen the data interpretation accuracy
Solution Approach 1:
The measured signal is segmented into distinct components: diffraction orders from the periodic structure and background signal from roughness and noise. By separating these components through angular span analysis, the patent enables independent processing and interpretation of each, improving dimensional characterization while accounting for background effects
Solution Approach 2:
The background signal component is extracted from the total measured signal by identifying regions where only background contributes (without diffraction orders). This extracted background is then subtracted from the complete signal, isolating the pure diffraction information needed for accurate dimensional measurement
2Loss of information
If a broader angular span is used to capture diffraction orders, then measurement completeness is improved, but background noise inclusion worsens
Solution Approach 1:
The patent utilizes the angular dimension of the measured signal to separate diffraction orders from background. By analyzing the angular distribution of the signal and identifying which angles contain diffraction orders versus only background, the method captures complete diffraction information while characterizing and removing background contributions
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 effectively removes background noise and roughness effects, enhancing the signal-to-noise ratio and improving the accuracy of dimensional characterization in X-ray scatterometry measurements.
Implementation Method 1
processing data indicative of measured signals corresponding to detected radiation response of a patterned structure to incident X-ray radiation
Implementation Method 2
One such technology is X-ray scatterometry (XRS), where scattered signal from monochromatic X-ray is analyzed for dimensional characterization
Data Source
AI summary
A method and system are presented for use in X-ray based measurements on patterned structures. The method comprises: processing data indicative of measured signals corresponding to detected radiation response of a patterned structure to incident X-ray radiation, and subtracting from said data an effective measured signals substantially free of background noise, said effective measured signals being formed of radiation components of reflected diffraction orders such that model based interpretation of the effective measured signals enables determination of one or more parameters of the patterned structure, wherein said processing comprises: analyzing the measured signals and extracting therefrom a background signal corresponding to the background noise; and applying a filtering procedure to the measured signals to subtract therefrom signal corresponding to the background signal, resulting in the effective measured signal.