Native defects in mask blanks is one of the key issues in extreme ultraviolet lithography. If defect-free mask blanks
is the only solution, the resulting cost will be very high due to the low yield of such blanks. In this paper, we present a
method for fabricating defect-free-like EUV masks by implementing several novel techniques such as global pattern shift,
fine metrology-orientation and precise e-beam second-alignment from blank preparation to e-beam exposure. The mitigation
success rate versus mask pattern density is simulated and verified by lithographic results using mitigated masks.
Our methodology provides a way to achieve defect-free-like EUV mask blanks.
In this study, the relationship between the depth profile of features and critical dimension (CD) deviation on MoSi
binary photomasks is comprehensively investigated using 3D atomic force microscopy (3D-AFM) and aerial image
metrology system (AIMS). Detailed profile description based on various surface analysis techniques, was performed to
reconstruct the profile at various stages of the mask fabrication process. It is found that profile change and sidewall
byproduct formation are strongly correlated with the etching environment, wet cleaning, and post-treatment. These
process-induced profile changes subsequently lead to wafer CD change which can be verified by deviation in AIMS and
CDSEM measurements. Visualization of these 3D profile and morphology change clearly reveals that etching gas
control forms an outer layer, to enhance etch selectivity, film strength, and immunity to the mask cleaning process. Our
finding provides a direction for optimizing advanced photomask materials and processing.
In this article, the polymer photovoltaic devices based on the poly(3-hexylthiophene)/TiO2 nanorods hybrid material is present. An enhancement in the device performance can be achieved by removing or replacing the insulating surfactant on the TiO2 nanorods surface with a more conductive ligand, which can play the role to assist charge separation efficiency or also to prevent from back recombination, giving a large improvement in the short circuit current and fill factor. The relatively high power conversion efficiency of 2.2 % under simulated A.M. 1.5 illumination (100mW/cm2) can be achieved, providing a route for fabricating low-cost, environmentally friendly polymer photovoltaic devices by all-solution processes.
This paper aims to propose a 3D nanostructured organic-inorganic hybrid photovoltaic device based on the ZnO
nanostructures/poly(3-hexylthiophene)(P3HT):TiO2 nanorods hybrids by solution processes at low temperature. An array
of ZnO nanorods with a larger size of ~50 nm in diameter and ~180 nm in length are grown to provide direct pathways
for efficient charge collection. TiO2 nanorods with a size of ~5 nm in diameter and ~20-30 nm in length are incorporated
into polymer to facilitate charge separation and transport by providing increased interfacial area and more effective
transport pathway. The device performance with the inclusion of TiO2 nanorods exhibits a seven times increase in the
short circuit current with respect to that without TiO2 nanorods.
The mechanisms of exciton dissociation and migration in the conjugated polymer
(poly(2-methoxy-5-(2'-ethyl)(hexyloxy)1,4-phenylenevinylene)(MEH-PPV) / CdSe nanoparticle
hybrid materials were investigated by steady-state and time-resolved photoluminescence spectroscopy.
Rapid exciton dissociation at the nanoparticle/polymer interfaces leading to quenching of the
η and shortening of the measured lifetime τPL is observed. The excitons
which contribute to the remaining luminescence in polymer will migrate to the lower energy sites with
longer conjugated sequences in the composites. The result is evident from the observations of a redshift
of the photoluminescence peak positions, a progressive decrease of the Huang-Rhys factor S and an
increase in the nature radiative lifetime τR with increasing CdSe nanoparticle content. The solar cell
based on the MEH-PPV / CdSe nanoparticle hybrid materials are fabricated and the transport
mechanism of the device will also be discussed.