Charged Particle Beam Probe Diameter Calibration
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Solution Overview
Problem
Existing charged particle beam devices face challenges in accurately measuring probe diameters and profiles due to fluctuations in probe diameter, which affect the precision of length measurements and inspections, especially as features become finer, and current calibration methods are inadequate for high accuracy.
Innovation Solution
A measurement device and calibration method that utilize a standard member with well-known line widths, separated to avoid interference, and an X-ray calibration system to measure and control probe diameters and profiles with absolute traceability, ensuring high accuracy in device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scanning probe microscope is used to measure the actual dimension of a calibration member, then measurement can be performed, but the probe diameter is too large to accurately measure fine patterns equivalent to the probe diameter
Solution Approach 1:
The patent replaces the mechanical scanning probe microscope with an optical measurement system using a charged particle beam device. This substitution allows measurement of fine patterns with dimensions comparable to or smaller than the probe diameter by using electromagnetic interaction instead of physical contact, thereby achieving high measurement accuracy without being limited by mechanical probe size.
Solution Approach 2:
The patent changes the measurement parameter from direct physical contact measurement to optical/electromagnetic field-based measurement. By using the charged particle beam to interact with the calibration member and detect secondary electrons, the system can resolve fine dimensions that are impossible to measure with conventional mechanical probes, thus improving measurement precision for sub-10nm features.
2Measurement precision
If multiple pattern groups are measured to acquire fluctuation or difference between devices, then probe diameter and profile can be determined, but measurement time and complexity increase
Solution Approach 1:
The patent divides the calibration member into multiple pattern groups with different line widths (e.g., 10nm, 20nm, 30nm, 40nm, 50nm) arranged in parallel. By measuring multiple pattern groups simultaneously or in sequence and analyzing the relationship between measured widths and actual widths, the system can determine probe diameter and profile through functional analysis, reducing the need for repeated measurements at different positions and thereby reducing total measurement time.
Solution Approach 2:
The patent creates a universal calibration member containing multiple pattern groups that can serve multiple measurement purposes. By measuring all pattern groups in a single calibration process, the system can characterize probe parameters (diameter, profile, spherical aberration) comprehensively, making the calibration process more efficient and reducing measurement time compared to measuring each parameter separately.
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 precise control of device performance by accurately measuring and adjusting probe diameters and profiles, improving the accuracy of length measurements and inspections in charged particle beam devices.
Implementation Method 1
an irradiation optical system that emits a primary charged quantum beam to a sample for scanning; a detector that detects secondary charged particles generated from the sample
Data Source
AI summary
Provided is a measurement device including: an irradiation optical system which emits a primary charged quantum beam to a sample for scanning; a detector which detects secondary charged particles generated from the sample; and a signal processing unit which processes an output signal from the secondary charged particle detector which has detected the secondary charged particles, in which the signal processing unit includes a measurement unit which measures widths of a first pattern group calibrated with a well-known first dimension and a second pattern group calibrated with a well-known second dimension, and an operation unit which defines a relationship between the well-known dimensions of the first and second pattern groups and length measurement values of the first and second pattern groups as a function. Accordingly, it is possible to control device performance with high accuracy, by controlling a device state so that the measured value described above is within an acceptable range by comparing to a predetermined value provided in advance.