Fourier spectrum method to determine dose-to-clear in a photoresist

Area of Science:

• Materials Science
• Electrical Engineering
• Nanotechnology

Background:

• Accurate determination of the dose-to-clear is critical for optimizing photolithography processes.
• Current methods rely on visual inspection, which is subjective and prone to operator variability.
• Developing objective and automated methods is essential for reproducible microfabrication.

Purpose of the Study:

• To introduce a novel Fourier spectrum method for automated dose-to-clear determination in photoresists.
• To replace subjective visual inspection with an objective, data-driven approach.
• To enhance the reliability and reproducibility of lithography process control.

Main Methods:

• Utilizing the frequency content analysis of scanning electron microscope (SEM) images of photoresist.
• Applying Fourier transform to quantify the dissolution state of the resist.
• Developing an algorithm to automatically calculate the dose-to-clear from spectral data.

Main Results:

• The Fourier spectrum method successfully determines the dose-to-clear.
• Automated calculation eliminates operator influence, leading to more consistent results.
• The method provides an objective measure of resist dissolution.

Conclusions:

• The proposed Fourier spectrum method offers an automated and objective alternative to visual inspection for dose-to-clear determination.
• This technique improves the precision and reproducibility of lithography processes.
• Implementation of this method can lead to enhanced control and optimization in semiconductor manufacturing.