This work reports on the development of a binary pseudo-random test sample optimized to calibrate the MTF of optical microscopes. The sample consists of a number of 1-D and 2-D patterns, with different minimum sizes of spatial artifacts from 300 nm to 2 microns. We describe the mathematical background, fabrication process, data acquisition and analysis procedure to return spatial frequency based instrument calibration. We show that the developed samples satisfy the characteristics of a test standard: functionality, ease of specification and fabrication, reproducibility, and low sensitivity to manufacturing error.
A step-and-repeat nanoimprint lithography (SR-NIL) process on a pre-spin-coated film is employed for the fabrication of an integrated optical device for on-chip spectroscopy. The complex device geometry has a footprint of about 3 cm2 and comprises several integrated optical components with different pattern size and density. Here, a new resist formulation for SR-NIL was tested for the first time and proved effective at dramatically reducing the occurrence of systematic defects due to film dewetting, trapped bubbles, and resist peel-off. A batch of 180 dies were imprinted, and statistics on the imprint success rate is discussed. Devices were optically characterized and benchmarked to an identical chip that was fabricated by electron-beam lithography. The overall performance of the imprinted nanospectrometers is well-aligned with that of the reference chip, which demonstrates the great potential of our SR-NIL for the low-cost manufacturing of integrated optical devices.
Numerous studies report the importance of nanoscale metallic features to increase the sensitivity of gas sensors, biodetectors, and for the fabrication of the new-generation plasmonic devices. So far, nanoimprint lithography has not shown the capability to pattern a metallic structure that would both be sub-15 nm and sufficiently thick to ensure electrical conductance. To overcome these limitations, we report a step and repeat nanoimprint lithography (SR-NIL) on a pre-spin-coated layer stack. This work reports the fabrication of sub-15-nm lines that are 15-nm thick and have a 50-nm-half-pitch grating with 35-nm-thick metal, which represents the new state of the art for SR-NIL.
This paper will review the top down technique of ICP etching for the formation of nanometer scale structures. The increased difficulties of nanoscale etching will be described. However it will be shown and discussed that inductively coupled plasma (ICP) technology is well able to cope with the higher end of the nanoscale: features from 100nm down to about 40nm are relatively easy with current ICP technology. It is the ability of ICP to operate at low pressure yet with high plasma density and low (controllable) DC bias that helps greatly compared to simple reactive ion etching (RIE) and, though continual feature size reduction is increasingly challenging, improvements to ICP technology as well as improvements in masking are enabling sub-10nm features to be reached. Nanoscale ICP etching results will be illustrated in a range of materials and technologies. Techniques to facilitate etching (such as the use of cryogenic temperatures) and techniques to improve the mask performance will be described and illustrated.
Proc. SPIE. 8324, Metrology, Inspection, and Process Control for Microlithography XXVI
KEYWORDS: Scanning electron microscopy, Metrology, Monte Carlo methods, Image analysis, Image quality, Cadmium, Sensors, Line width roughness, Critical dimension metrology, Line edge roughness
The uncertainty associated with scanning electron microscopy (SEM) metrology is significant because
SEM image brightness is complexly related to the size and shape of the feature, its material, the geometry of
the pattern, as well as SEM setup. While regularly used methods of extracting critical dimensions (CD) rely
on image brightness analysis, the myCD software uses a physical model of the SEM in order to improve the
accuracy of measurements. Metrology below 10 nm was studied in this paper. Patterns were fabricated
using electron beam lithography and nanoimprint; they were imaged by SEM and examined using myCD.
Factors that are important for metrology at the sub-10 nm size range were studied using advanced Monte
Carlo software; the beam size, voltage, detector and linewidth were varied. SEM images were processed
using myCD, which utilizes an analytic model of the SEM and so does not require any libraries. The top and
bottom sizes, as well as wall angles and line width roughness were analyzed. The CD and profile results
from top down SEM images were compared to the vertical crossections. The challenges of sub-10 nm
metrology are discussed, mainly regarding the quality of SEM images and the physics of image formation.
BEAMETR (BEAm METRology) technique is demonstrated as an attractive solution for automatic
measurement of electron beam sizes in two coordinates. The method associates one software and one
specially designed pattern chip. The fabrication of new BEAMETR design is performed by electron beam
lithography and metal lift-off. A specific bi-layer resist system and proximity correction is used for achieving
the requirements for the "pound-key" shape of BEAMETR pattern. Beam sizes in two coordinates (x,y) of
Scanning Electron Microscope are measured for various operating conditions. This method allows measuring
electron beam sizes down to 2 nanometers.
We measure electronic and thermal nonlinear refractive indices of periodically nano-patterned and un-patterned siliconon-
insulator (SOI) in comparison with that of bulk silicon, using a fast reflection Z-scan setup with a high-repetition-rate
fs laser (at 800 nm wavelength), and a new procedure for discrimination between electronic and thermal nonlinearities.
The electronic nonlinear response of nano-structured SOI is strongly enhanced in comparison with those of un-patterned
SOI and of bulk Si. These results could be important in silicon photonics for optical devices with nonlinearity controlled
by periodic nano-structuring.
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