Development of nanoimprint lithography (NIL) templates is discussed. The template fabrication process and its performance are presented with consideration of the requirements of NIL for high-volume manufacturing. Defectivity, image placement, and critical dimension uniformity are the three major performance parameters of the templates, and their current status is shown.
Performances of the nanoimprint lithography templates were discussed considering the readiness toward the high volume manufacturing of nanoimprint lithography application along with the requirement for the templates and its fabrication process. The current status of the three major performances of the templates was shown.
Most problems in photomask fabrication such as pattern collapse, haze, and cleaning damage are related to the behavior
of surfaces and interfaces of resists, opaque layers, and quartz substrates. Therefore, it is important to control the
corresponding surface and interface energies in photomask fabrication processes. In particular, adhesion analysis in
microscopic regions is strongly desirable to optimize material and process designs in photomask fabrication. We applied
the direct peeling (DP) method with a scanning probe microscope (SPM) tip and measured the adhesion of resist patterns
on Cr and quartz surfaces for photomask process optimization. We measured adhesion and frictional forces between the
resulting collapsed resist pillar and the Cr or the quartz surface before and after the sliding. We also studied the effect of
surface property of the Cr and quartz surfaces to resist adhesion. The adhesion could be controlled by surface
modification using silanes and surface roughness on Cr blanks. We also discuss the relationship between the adhesion
observed with the DP method and the properties of the modified surfaces including water contact angles and local
adhesive forces measured from force-distance curves with an SPM.
Most of photomask issues such as pattern collapse, HAZE, and cleaning damage relate to behavior of mask surfaces. Therefore it is coming to be important to control surface energy in photomask processes. Especially adhesion analysis in micro region is strongly desired to optimize material and process designs in photomask fabrication. Quantitative measurements of adhesive forces of resists on photomask blanks were realized with scanning probe microscopy (SPM) techniques. Then surface energy on photomask blanks was able to be controlled by modification with some silanization reagents. In addition, adhesive forces of resists on surfaces modified with some silanes were able to be also controlled. The SPM method is proved to be effective for measuring adhesive energy of micro patterns on photomask blanks.
Templates for UV-Nano-imprint lithography (NIL) have been rapidly improved these days. Feature sizes of the
templates have come to be less than 30 nm. Consequently, metrology has been also one of the challenges to fabricate
templates for UV-NIL. There are many issues in metrology for the templates; for instance, necessity of the higher
resolution, critical dimension (CD) accuracy and repeatability for measurement tools.
In this paper, we will focus on an optimization of measuring conditions for the templates of UV-NIL. And we will
discuss some measuring techniques for CD precision and repeatability using a CD-SEM and a scanning probe
Templates for UV-Nano-imprint lithography (NIL) have developed aggressively. Feature sizes of the templates have
come to less than 30 nm. Therefore metrology is also one of challenging items to fabricate templates for UV-NIL.
However, there are many issues in metrology for the templates, for instance, necessity of the further resolution for
measurement tools, charging issues without conductive layers for a SEM.
In this paper, we will focus on metrology of the templates for UV-NIL. And also some measurement techniques are
described about detail results using scanning probe microscope, CD-SEM, scattermetry and so on.
A lot of source shapes have been proposed for resolution enhancement in semiconductor exposure field, and so-called OAI (OAI: Off Axis Illumination) in them improves not only the resolution but also defocus behavior. Such kind of small window illumination was realized aperture filter at first stage but there were issues of efficiency of light source and complex OPC due to higher coherency. The advantages of use DOE (DOE : Diffractive Optical Element ) are not only the flexible illumination shape available but also the controllability of intensity profile in addition to the higher efficiency of light source. However DOE design and fabrication to obtain enough resolution are difficult due to the huge design load and leading-edge fabrication. Not enough design and fabrication error lead unintended intensity distribution, and the distribution degrades the resolution and makes OPC less effective so that photomask specification shall be tighter.
In this paper, as one example, dipole source shape named "Soft-Dipole" is optimized considering intensity distribution targeting 90nm with simulator and is estimated the impact to resolution and OPC. Then actual DOE is fabricated for the intended distribution and evaluated the behavior with the simulator of the DOE using captured intensity distribution. The result showed Soft-Dipole illumination had possibilities to reduce OPC load with enough resolution. Then the DOE design, the fabrication and the evaluation are discussed in this paper.
We have investigated the electronic structures of GaAs/Al(Ga)As and GaAs/AlAs quantum wells by resonance effects of second-harmonic generation. Second-harmonic generation signals manifest themselves in two-photon resonance with the confined 1S and/or 2P excitons in GaAs/Al(Ga)As and ZnSe/ZnS quantum wells. The assignment of the resonance is directly determined from comparison to the results of one-photon and two-photon absorption data. From the energy splitting of the 1S and 2P exciton levels, the exciton binding energies can be determined. There is a significant increase in the binding energy as compared to that in bulk materials. This increase is caused by the exciton confinement effect.