Calibration Substrate for LER Measurement
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Solution Overview
Problem
Current measurement apparatuses, such as CD-SEM, face challenges in accurately calculating line edge roughness (LER) due to noise interference, and lack a standard sample with known LER and correlation length for calibration, making precise measurement of LER in semiconductor devices difficult.
Innovation Solution
A substrate with specifically designed line patterns having side surfaces with {111} crystal planes and controlled atomic steps is used for calibration, allowing for the creation of a sample with known LER and correlation length, enabling accurate calibration of measurement apparatuses and subsequent precise measurement of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement is performed by a measurement apparatus such as CD-SEM, then LER can be calculated, but noise of the measurement apparatus interferes with measurement accuracy
Solution Approach 1:
A calibration sample with known LER and correlation length is introduced as an intermediary between the measurement apparatus and actual semiconductor devices. This calibration sample serves as a reference standard that enables the measurement apparatus to characterize and correct its own noise properties, thereby improving measurement accuracy without requiring modification to the apparatus itself.
2Measurement precision
If calibration is performed without a standard sample, then measurement can proceed, but accurate calibration of LER and correlation length cannot be achieved
Solution Approach 1:
A calibration sample with predetermined known LER and correlation length values is prepared in advance. This preliminary preparation of a reference standard enables systematic calibration procedures where the measurement apparatus can compare its measurements against known values, thereby achieving accurate calibration without requiring complex iterative adjustment processes.
3Measurement precision
If conventional calibration methods are used, then general measurement can be performed, but precise measurement of small LER values cannot be achieved
Solution Approach 1:
The calibration sample is designed with specific parameter values for LER and correlation length that match the measurement range requirements. By changing and optimizing these parameters in the calibration sample to match the target measurement conditions, the measurement apparatus can be calibrated for high-precision measurement of small LER values, thereby enabling accurate characterization of finely formed patterns.
Data Source
AI summary
A pattern according to an embodiment includes first and second line patterns, each of the first and second line patterns extends in a direction intersecting a <111> direction and has a side surface, the side surface has at least one {111} crystal plane, the side surface of the first line pattern has a first roughness, and the side surface of the second line pattern has a second roughness larger than the first roughness.