[Model-based FTIR reflectometry measurement system for deep trench structures of DRAM]

Area of Science:

• Optics and Photonics
• Materials Science
• Semiconductor Device Physics

Context:

• Accurate measurement of deep trench structures is critical for advanced semiconductor manufacturing, particularly for dynamic random access memory (DRAM) devices.
• Existing metrology techniques may face limitations in resolution, cost, or throughput for nanoscale features.
• Fourier Transform Infrared (FTIR) reflectometry offers a potential non-destructive approach for in-situ process monitoring.

Purpose:

• To propose and validate a novel method and system for measuring deep trench structures in DRAM using FTIR reflectometry.
• To enhance the signal-to-noise ratio (SNR) of FTIR measurements by optimizing optical parameters.
• To demonstrate the capability of extracting trench geometric parameters with nanometer-scale accuracy.

Summary:

• A measurement system based on FTIR reflectometry is developed for deep trench structures.
• Key innovations include regulating slit aperture and optimizing incidence angle to suppress backside reflection and improve SNR.
• Experimental results confirm nanometer-scale accuracy in extracting trench geometric parameters, validating the system's effectiveness.

Impact:

• Provides a non-contact, non-destructive, time-effective, and low-cost metrology tool for high-resolution measurement of deep trench structures.
• Enables precise on-line monitoring and process control in microelectronics and microelectromechanical system (MEMS) manufacturing.
• Potential to improve yield and reduce costs in semiconductor fabrication processes.