What is overlay metrology?

What is overlay metrology?

Overlay metrology involves a process of taking a multitude of measurements between two (or more) different layers. In simple terms, the overlay metrology system is taking various measurements, such as tool alignment accuracy, wafer/mask distortions and variation.

What is overlay in VLSI?

The ability of a lithography scanner to align and print various layers accurately on top of each other.

What is semiconductor metrology?

Semiconductor metrology instruments are designed for wafer and thin film in-line inspection after semiconductor processing. By using semiconductor metrology instruments, manufacturers can facilitate semiconductor inspection, reduce manufacturing costs, and shorten the product development cycle.

What is optical scatterometry?

Optical Scatterometry is a method of characterizing unknown properties of a sample by measuring the reflection of broadband light from an object. The reflection varies by wavelength (color), polarization, and angle-of-incidence.

What is CPE in semiconductor?

A field-by-field correction (FxFc) or correction per exposure (CPE) methodology to improve high order overlay signature without changing current APC-linear control system is demonstrated.

What are the types of metrology?

Metrology can be divided into three subfields: scientific metrology, applied metrology, and legal metrology.

What is the need of inspection in metrology?

As such, the main objective of inspection in the field of Precision Engineering and Metrology is to quantify the dimensional characteristics of components by means of measurements and to compare the results of those measurements with the product specifications (ISO 8015 2011).

What does the ellipsometer check?

Ellipsometry measures the change of polarization upon reflection or transmission and compares it to a model. It can be used to characterize composition, roughness, thickness (depth), crystalline nature, doping concentration, electrical conductivity and other material properties.

What is scatterometry metrology?

Scatterometry is a metrology technique that combines the sensitivity of diffraction from periodic structures with a first principle solution of electromagnetic wave diffraction from these structures.

What are 3 main categories of metrology?

What is a metrology device?

These machines use a measuring probe to determine coordinates of points on a workpiece surface. They provide precise measurements of objects for design, testing, assessment, profiling, and reverse engineering of parts.

What is calibration in metrology?

In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy.

Which machine learning techniques for after etch in-cell on-device overlay metrology?

We investigate two types of machine learning techniques with SE data: model-less and model-based, showing excellent performance for after etch in-cell on-device overlay metrology. 1. Introduction Overlay process control has been a critical part of integrated circuit manufacturing for many years.

What is advanced scribe-line overlay metrology?

A typical advanced scheme includes an overlay feedback loop based on after litho optical imaging overlay metrology on scribe-line targets. The after litho control loop typically involves high frequency sampling: every lot or nearly every lot.

What is the after etch overlay metrology step?

An after etch overlay metrology step is often included, at a lower sampling frequency, in order to characterize and compensate for bias. The after etch metrology step often involves CD-SEM metrology, in this case in-cell and on-device.

What is AEI overlay metrology?

To bridge this gap, after etch metrology or AEI (after etch inspection) is added to characterize and correct for the bias. AEI overlay metrology is often done with a CD-SEM in order to measure in-cell, on-device, and at design rule.