Characterization of nanostructures using optical far field techniques

Project

Determination of side wall angle of nanostructures


Summary

Using coherent scanning Fourier scatterometry to obtain information about side wall angle based on focusing light onto a structure and obtain the far field as the structure is scanned along the lateral direction.


Research description

In the semiconductor industry, the quality of the lithographic processes are evaluated by determining some parameters of specific structures. These structures are often gratings of which the shape is described by geometrical parameters such as period, MidCD, height and side wall angle.

Far field optical scatterometry is a powerful tool that is used in the semiconductor industry to determine these parameters. The technique is based on shinning a light beam onto the structure and recording the far field intensity at various angles. The obtained data is used in combination with a numerical model based on a priori information about the structure, and it has been shown that the parameters can be determined with subwavelength accuracy. But it is also known that, among these parameters, the accuracy on the determination of the side wall angle is the most challenging problem, since this has usually nominal values close to 90 degrees.

In this case, the changes of the far field intensity as the side wall angle is tuned within a few degrees from this nominal value are extremely small and it is very hard to determine it.

Recently, coherent scanning Fourier scatterometry has been introduced as an alternative way to obtain information about side wall angle based on focusing light onto a structure and obtain the far field as the structure is scanned along the lateral direction. In general, the modelling of side wall angle based on numerical methods is difficult to implement because these angles are very steep, and the discretization of the structure may not be accurate enough. A new approach based on an analytical model to study the far field scattering of a cliff and a ridge structure with steep side wall angles has been developed by the group recently.


Keywords

Projects.

View all on the projectspage.

Far field nanoparticle detection

We investigate and optimize new techniques to detect nanostructures and nano-particles in semiconductor, and plastic-based fabrication technologies. The technique should be fast, operate in-line and applicable to large areas. Since the structures ...

project

Far field nanoparticle detection

LINX

LINX is a NWO-TTW perspective programme with the aim to apply various lensless imaging techniques, from ptychography to scatterometry, while using wavelengths in the EUV and Soft X-Ray regime. This programme is ...

project

LINX

Characterization of nanostructures using optical far field techniques

Determination of side wall angle of nanostructures ...

project

Characterization of nanostructures using optical far field techniques

Electromagnetic modeling of SLM

The spatial light modulator (SLM), especially liquid crystal on silicon (LCoS) type has multiple applications in optical systems, such as beam steering, beam shaping or computational holography. At the same time, there ...

project

Electromagnetic modeling of SLM

Phase Retrieval

The phase of a field is often more important than the amplitude. This is in particular true for focusing of light. To improve the quality of imaging it is often desirable to consider ...

project

Phase Retrieval

News.

Related to the topic at hand.

Soft X-Ray source based on HHG for LINX project

The Optics Research Group recently installed a coherent Soft X-Ray source based on High Harmonic Generation. This new source will have an important role within the LINX consortium, where innovative techniques for ...

News - October 15, 2020

Soft X-Ray source based on HHG for LINX project

Beijing Institute of Space Mechanics and Electricity

A delegation of  50 people from BISME (Bejing Institute of Space Mechanics and Electricity) has visited the Optics Group. The delegation was in  the Netherlands to attend the 6th International Symposium ...

News - October 7, 2019

Beijing Institute of Space Mechanics and Electricity

Weekend of Science – Oct 5-6, 2019

The Weekend of Science is a national science weekend. Every year, various technical institutions open their doors to provide extra activities. This year the theme of our Weekend of Science is: LIGHT. Date ...

News - September 25, 2019

Weekend of Science – Oct 5-6, 2019

Face2Phase – Oct 21-23, 2019

The conference Fase2Phase, 2nd Edition, addresses imaging with phase information and covers topics such as lensless imaging, aberration retrieval, adaptive and active optics, ptychography, holography, tomography, phase retrieval and applications. Date : 21 ...

News - September 10, 2019

Face2Phase – Oct 21-23, 2019