Virtual X-ray critical dimension metrology via Monte Carlo simulation

Area of Science:

• Materials Science and Engineering
• Semiconductor Manufacturing Technology
• Metrology and Measurement Science

Background:

• X-ray critical dimension (XCD) metrology is crucial for sub-nanometer precision in advanced integrated circuit manufacturing.
• Compact X-ray sources present challenges in XCD, including extended testing times and increased measurement uncertainty compared to synchrotron sources.

Purpose of the Study:

• To develop an *ab initio* virtual X-ray critical dimension metrology (MC-VXCD) tool using Monte Carlo simulations.
• To evaluate the influence of experimental conditions on XCD measurement accuracy and throughput.
• To provide a versatile platform for optimizing XCD instrument design and experimental configurations.

Main Methods:

• Development of a Monte Carlo simulation-based virtual XCD metrology (MC-VXCD) platform.
• Calibration of MC-VXCD system parameters against a home-built compact XCD instrument.
• Simulation of measurement errors, particularly those related to reduced exposure time.

Main Results:

• Excellent consistency was achieved between virtual measurements from MC-VXCD and actual measurements from the physical instrument.
• The MC-VXCD effectively estimated measurement errors influenced by reduced exposure time, impacting accuracy and throughput.
• A clear connection was established between XCD metrology application scenarios and XCD instrument geometry.

Conclusions:

• The MC-VXCD serves as a powerful and versatile tool for XCD metrology.
• This virtual metrology approach aids in system design, experimental optimization, and data analysis for advanced semiconductor manufacturing.
• MC-VXCD facilitates improved accuracy and efficiency in critical dimension measurements.