Device based in-chip critical dimension and overlay metrology

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Manufacturing

Background:

• Optical metrology is crucial for microelectronic process control due to its speed and non-destructive nature.
• Existing optical methods often require dedicated scribe line structures, limiting process characterization.
• In-chip measurements offer a solution to overcome limitations of traditional metrology.

Purpose of the Study:

• To present an in-chip optical metrology technique for direct measurement within semiconductor devices.
• To demonstrate the capability of measuring critical dimensions and overlay displacement errors.
• To address the limitations of traditional metrology by eliminating the need for special test structures.

Main Methods:

• Development and experimental validation of an in-chip optical metrology approach.
• Application of the technique to the DRAM manufacturing process.
• Direct measurement on actual semiconductor devices without fabricated targets.

Main Results:

• Successful in-chip measurement of critical dimensions.
• Accurate detection of overlay displacement errors in DRAM manufacturing.
• Demonstration of a technique that bypasses the need for scribe line test structures.

Conclusions:

• The presented in-chip optical metrology technique is effective for characterizing lithography processes.
• This method allows for direct, non-destructive measurement on functional devices.
• It offers significant advantages over traditional metrology by integrating measurements directly into the chip.