Raman Wafer Measurement With Reference Signal Correction
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Solution Overview
Problem
Existing techniques for measuring semiconductor devices at nanometer scales face challenges in accuracy and reliability, particularly in determining dopant concentrations, due to variations in Raman scattering signals and the need for manual wafer positioning.
Innovation Solution
A semiconductor device measuring device and method that includes a wafer stage with load ports for reference and sample wafers, a polarizer to adjust polarization, a spectroscope for Raman spectral information collection, and a processor to correct and determine dopant concentration using corrected Raman scattering signals, enabling automated and accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual wafer positioning is used, then device complexity is reduced, but measurement precision deteriorates due to positioning errors and variations
Solution Approach 1:
The wafer stage is pre-configured with multiple load ports (first load port for reference wafer, second load port for sample wafer) positioned at predetermined locations. This preliminary arrangement eliminates the need for manual positioning during measurement, as the automated system simply moves between pre-defined positions, thereby improving measurement precision without excessive complexity
Solution Approach 2:
The system automatically performs wafer positioning and Raman signal acquisition by moving the wafer stage to predetermined positions corresponding to different load ports. The automated control replaces manual operation, reducing positioning errors while maintaining manageable device complexity through systematic automation
2Reliability
If Raman scattering signals are measured without correction, then measurement time is reduced, but reliability deteriorates due to signal variations
Solution Approach 1:
The system measures Raman scattering signals from both reference wafers (undoped) and sample wafers (doped) and uses the reference signals as feedback to correct the sample signals. This feedback mechanism compensates for signal variations and improves measurement reliability, with the correction process integrated into the measurement workflow to minimize additional time loss
Solution Approach 2:
The reference wafer acts as an intermediary element that mediates between the light source and the sample wafer measurements. By measuring the reference wafer first and using its Raman signal as a baseline, the system can correct subsequent sample measurements, thereby improving reliability without requiring complex real-time adjustments
3Measurement precision
If polarization direction is not optimized, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The polarizer is made rotatable, allowing the polarization direction to be dynamically adjusted to optimize the Raman scattering signal intensity for different measurement conditions. This dynamic adjustment capability enables precise measurements while the automated control system manages the complexity of polarization optimization, maintaining ease of operation
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
Enhances measurement accuracy and reliability by correcting Raman scattering signals and optimizing polarization angles, allowing for precise dopant concentration determination even in three-dimensional semiconductor structures.
Implementation Method 1
a polarizer configured to polarize the light
Implementation Method 2
a spectroscope configured to collect first Raman spectral information of light reflected from the reference wafer and collects second Raman spectral information of light reflected from the sample wafer
Data Source
AI summary
A semiconductor device measuring device includes: a light generator which generates light; a polarizer which polarizes the light; a wafer stage including a first load port on which an undoped reference wafer is loaded, and a second load port on which a doped sample wafer is loaded, the wafer stage being movable to first and second positions at which the polarized light is incident on the reference wafer and the sample wafer, respectively; a spectroscope which collects first and second Raman spectral information of light reflected from the reference and sample wafers, respectively; a photodetector which detects first and second Raman scattering signals based on the first and second Raman spectral information, respectively; a spectrum corrector which corrects the second Raman scattering signal using the first Raman scattering signal; and a controller which calculates a concentration of the dopant of the sample wafer using the corrected scattering signal.