Polarization Spectrum OCD for Local CD Dispersion Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical Critical Dimension (OCD) techniques struggle with accurately measuring local dispersion within measurement areas of semiconductor devices, as they are non-destructive but lack precision in characterizing dispersion within larger areas like wafers.
Innovation Solution
A method using an electronic device with a light source, optical systems, and a detector to measure semiconductor devices by analyzing polarization spectrum data and extracting depolarization information, enabling accurate calculation of critical dimension dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OCD technique is used for non-contact measurement, then measurement speed and non-destructiveness are improved, but measurement precision of local dispersion deteriorates
Solution Approach 1:
The patent changes the measurement parameter from simple optical intensity to polarization state of reflected light. By analyzing depolarization information extracted from polarization spectrum data, the system can measure local dispersion with high precision while maintaining the non-contact and high-speed advantages of OCD techniques. The processor calculates depolarization metrics from the polarization state changes, enabling accurate local dispersion measurement that overcomes the traditional limitation of OCD methods.
2Measurement precision
If local average is calculated within each measurement area, then overall wafer dispersion is measured accurately, but local dispersion within each cell cannot be measured accurately
Solution Approach 1:
The patent extracts depolarization information from polarization spectrum data, which contains local dispersion characteristics that are otherwise lost in traditional local average calculations. By specifically extracting the polarization state changes and calculating depolarization metrics, the system retrieves local dispersion information at the cell level while still providing accurate wafer-level statistics, thus preventing information loss.
3Device complexity
If traditional OCD measurement is used, then measurement process is simple, but depolarization information and local dispersion cannot be extracted
Solution Approach 1:
The patent introduces polarization spectrum data as an intermediary between the reflected light and the final measurement result. The polarization state acts as a mediator that carries depolarization information through the optical system to the detector, where it can be extracted and processed. This intermediary approach enables the extraction of local dispersion information without fundamentally complicating the overall measurement system architecture.
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 allows for precise measurement of local dispersion in semiconductor devices by processing electrical signals from reflected light, enhancing the accuracy of critical dimension analysis.
Implementation Method 1
reflected light which is reflected from a target sample after passing through the first optical system
Implementation Method 2
obtaining polarization spectrum data corresponding to a change in a polarization state of the reflected light
Data Source
AI summary
Provided a method for measuring a semiconductor device by an electronic device, including a light source assembly including a light source configured to emit light and a first optical system in a traveling path of the light, a light reception assembly including a second optical system in a traveling path of reflected light which is reflected from a target sample and a detector configured to detect the reflected light, and a processor configured to process an electrical signal from the light reception assembly and obtain a dispersion of a critical dimension of the target sample, the method including obtaining polarization spectrum data corresponding to a change in a polarization state of the reflected light based on the electrical signal, extracting depolarization information corresponding to a degree of depolarization in the reflected light, and obtaining the dispersion of the critical dimension of the target sample based on the depolarization information.