Defect analysis and alignment quantification of line arrays prepared by directed self-assembly of a block copolymer

Trabajo presentado al XXVIII Metrology, Inspection, and Process Control for Microlithography, celebrado en California (US) en 2014.Different linear patterns obtained from the directed self-assembly of the block copolymer (BCP) polystyrene-b-polyethylene oxide (PS-b-PEO) were analysed and compared. The hexagonal phase PS-b-PEO in a thin film exhibits linear pattern morphology, by conventional solvent annealing in an atmosphere saturated in chloroform. The surface energy of the silicon substrates was varied using surface functionalization of a self-assembly monolayer (SAM) and a polymer brush, chosen to investigate the influence of the surface energy on the self-assembly of the BCP. The linear patterns formed were analyzed with innovative image analysis software specifically developed in our laboratory to identify elements and defects of line arrays from block copolymer self-assembly. The technique starts by performing dimensional metrology to calculate the pitch size and estimate the linewidth of the lines. Secondly, the methodology allows identification and quantification of typical defects observable in BCP systems, such as turning points, disclination or branching points, break or lone points and end points. The defect density and the quantification of the alignment were estimated using our technique. The methodology presented here represents a step forward in dimensional metrology and defect analysis of BCP DSA systems and can be readily used to analyze other lithographic or non-lithographic patterns.The research leading to these results received funding from the European Union FP7 under the project LAMAND (grant agreement n° 245565), the Spanish MICIN under the project TAPHOR (contract nr. MAT2012-31392) and the Science Foundation Ireland under grant number 09/SIRG/I1615.Peer Reviewe

Integrated 3D Hydrogel Waveguide Out-Coupler by Step-and-Repeat Thermal Nanoimprint Lithography: A Promising Sensor Device for Water and pH

Hydrogel materials offer many advantages for chemical and biological sensoring due to their response to a small change in their environment with a related change in volume. Several designs have been outlined in the literature in the specific field of hydrogel-based optical sensors, reporting a large number of steps for their fabrication. In this work we present a three-dimensional, hydrogel-based sensor the structure of which is fabricated in a single step using thermal nanoimprint lithography. The sensor is based on a waveguide with a grating readout section. A specific hydrogel formulation, based on a combination of PEGDMA (Poly(Ethylene Glycol DiMethAcrylate)), NIPAAm (N-IsoPropylAcrylAmide), and AA (Acrylic Acid), was developed. This stimulus-responsive hydrogel is sensitive to pH and to water. Moreover, the hydrogel has been modified to be suitable for fabrication by thermal nanoimprint lithography. Once stimulated, the hydrogel-based sensor changes its topography, which is characterised physically by AFM and SEM, and optically using a specific optical set-up

Total Mass TCI driven by Parametric Estimation

This paper presents the Total Mass Target Controlled Infusion algorithm. The system comprises an On Line tuned Algorithm for Recovery Detection (OLARD) after an initial bolus administration and a Bayesian identification method for parametric estimation based on sparse measurements of the accessible signal. To design the drug dosage profile, two algorithms are here proposed. During the transient phase, an Input Variance Control (IVC) algorithm is used. It is based on the concept of TCI and aims to steer the drug effect to a predefined target value within an a priori fixed interval of time. After the steady state phase is reached the drug dose regimen is controlled by a Total Mass Control (TMC) algorithm. The mass control law for compartmental systems is robust even in the presence of parameter uncertainties. The whole system feasibility has been evaluated for the case of Neuromuscular Blockade (NMB) level and was tested both in simulation and in real cases

Order quantification of hexagonal periodic arrays fabricated by in situ solvent-assisted nanoimprint lithography of block copolymers

arXiv:1403.2250v1Directed self-assembly of block copolymer polystyrene-b-polyethylene oxide (PS-b-PEO) thin film was achieved by a one-pot methodology of solvent vapor assisted nanoimprint lithography (SAIL). Simultaneous solvent-anneal and imprinting of a PS-b-PEO thin film on silicon without surface pre-treatments yielded a 250 nm line grating decorated with 20 nm diameter nanodots array over a large surface area of up to 4' wafer scale. The grazing-incidence small-angle x-ray scattering diffraction pattern showed the fidelity of the NIL stamp pattern replication and confirmed the periodicity of the BCP of 40 nm. The order of the hexagonally arranged nanodot lattice was quantified by SEM image analysis using the opposite partner method and compared to conventionally solvent-annealed block copolymer films. The imprint-based SAIL methodology thus demonstrated an improvement in ordering of the nanodot lattice of up to 50%, and allows significant time and cost reduction in the processing of these structures.The research leading to these results received funding from the European Union FP7 under the project LAMAND (grant agreement n° 245565), NANOFUNCTION (grant agreement no. 257375, FP7-ICT-2009-5) and by the Spanish Ministry of Economics and Competitiveness under project TAPHOR contract no. MAT2012-31392 (Plan Nacional de I + D + I (2008–2011)Peer Reviewe

Order quantification of hexagonal periodic arrays fabricated by in situ solvent-assisted nanoimprint lithography of block copolymers

Directed self-assembly of block copolymer polystyrene-b-polyethylene oxide (PS-b-PEO) thin film was achieved by one-pot methodology of solvent vapour assisted nanoimprint lithography (SAIL).Comment: 12 pages, 4 figures, paper accepte

Study of the kinetics and mechanism of rapid self-assembly in block copolymer thin films during solvo-microwave annealing

Microwave annealing is an emerging technique for achieving ordered patterns of block copolymer films on substrates. Little is understood about the mechanisms of microphase separation during the microwave annealing process and how it promotes the microphase separation of the blocks. Here, we use controlled power microwave irradiation in the presence of tetrahydrofuran (THF) solvent, to achieve lateral microphase separation in high- lamellar-forming poly(styrene-b-lactic acid) PS-b-PLA. A highly ordered line pattern was formed within seconds on silicon, germanium and silicon on insulator (SOI) substrates. In-situ temperature measurement of the silicon substrate coupled to condition changes during "solvo-microwave" annealing allowed understanding of the processes to be attained. Our results suggest that the substrate has little effect on the ordering process and is essentially microwave transparent but rather, it is direct heating of the polar THF molecules that causes microphase separation. It is postulated that the rapid interaction of THF with microwaves and the resultant temperature increase to 55 degrees C within seconds causes an increase of the vapor pressure of the solvent from 19.8 to 70 kPa. This enriched vapor environment increases the plasticity of both PS and PLA chains and leads to the fast self-assembly kinetics. Comparing the patterns formed on silicon, germanium and silicon on insulator (SOI) and also an in situ temperature measurement of silicon in the oven confirms the significance of the solvent over the role of substrate heating during "solvo-microwave" annealing. Besides the short annealing time which has technological importance, the coherence length is on a micron scale and dewetting is not observed after annealing. The etched pattern (PLA was removed by an Ar/O-2 reactive ion etch) was transferred to the underlying silicon substrate fabricating sub-20 nm silicon nanowires over large areas demonstrating that the morphology is consistent both across and through the film

Leprosy-specific oral lesions : a report of three cases

Leprosy is a chronic infection caused by Mycobacterium leprae, a bacillus that presents a peculiar tropism for the skin and peripheral nerves. The clinical spectrum of leprosy ranges from the tuberculoid form (TT) to the disseminative and progressive lepromatous form (LL). Oral lesions are rare but, when present, occur in the lepromatous form. This article describes the clinical and microscopic findings of three cases of LL with oral manifestations. All patients had the lepromatous form and their leprosy-specific oral lesions occurred in the palate. The diagnosis was based on clinical, serological and histopathological findings, and multidrug therapy for multibacillary leprosy was started and continued for 24 months. All patients completed treatment, but developed reaction episodes which were treated with prednisone and/or thalidomide. The authors emphasize the importance of oral mucosa evaluation by a dental health professional during patient care since oral lesions may act as a source of infection

Interruptor molecular hidrofóbico-hidrofílico, dispositivo que lo contiene y procedimiento para el control de la hidrofobicidad en superficie

El interruptor comprende un sustrato sólido que lleva anclado en su superficie moléculas de policlorotrifenilmetilo (PTM) funcionalizadas y en un estado de oxidación radical o anión, tal que proporcionan una superficie hidrofóbica, una superficie hidrofílica o una superficie con zonas hidrofóbicas y zonas hidrofilicas, y medios para cambiar reversiblemente dicho estado de oxidación de radical a anión o viceversa y localmente en el sustrato. La invención también se refiere al dispositivo de memoria que contiene dicho interruptor así como un módulo de acondicionamiento de la señal y un módulo de tratamiento de la misma. El interruptor y dispositivo que lo contiene tienen especial aplicación en el campo de la microfluídica, como dispensadores de biomoléculas o biosensores, en la fabricación de etiquetas o marcadores o en el campo de las superficies autolimpiantes.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Order and defectivity nanometrology by image processing and analysis of sub-20 nm BCPs features for lithographic applications

Trabajo presentado al III Dimensional Optical Metrology and Inspection for Practical Applications, celebrado en Baltimore (US) del 5 al 6 de mayo de 2014.The line patterns obtained by the self-assembly of the block copolymer (BCP) polystyrene-b-polyethylene oxide (PS-b-PEO) was investigated. The hexagonal PS-b-PEO 42k-11.5k in a thin film was solvent annealed in a chlorophorm saturated atmosphere for three different annealing times. The microphase segregation of this BCP returned 18nm cylinders of PEO through the PS matrix, with an approximately 40 n periodicity, as expected. Under chlorophorm vapours, the PEO cylinders oriented perpendicular to the silicon substrate while increasing the annealing time. These cylinders formed linear patterns with different alignment. To achieve insights about the percentage of alignment, defect type pareto and density, and order quantification to compare the three annealing recipes, the samples were analysed with innovative image analysis software specifically developed in our laboratory to identify elements and defects of line arrays from block copolymer self-assembly. From this technique, it was extracted dimensional metrology estimating pitch size and placement error, and the line-width of the lines was estimated. Secondly, the methodology allows identification and quantification of typical defects observable in BCP systems, such as turning points, disclination or branching points, break or lone points and end points. The defect density and the quantification of the alignment were estimated using our technique. The methodology presented here represents a step forward in dimensional metrology and defect analysis of BCP DSA systems and can be readily used to analyze other lithographic or non-lithographic patterns.The research leading to these results received funding from the European Union FP7 under the project LAMAND (grant agreement n° 245565), MERGING (grant agreement no. 309150) and QUANTIHEAT (grant agreement no. 604668), and the Spanish MINECO under the project TAPHOR (contract nr. MAT2012-31392) and the Science Foundation Ireland under grant number 09/SIRG/I1615.Peer Reviewe

Formation of titanium nanostructures on block copolymer templates with varying molecular weights

A novel and simple method for producing mesoporous titanium films and supported titanium nanoparticle hexagonal arrays is presented. During evaporation on block copolymer templates, titanium self-assembles as either a mesoporous film or as a hexagonal close-packed nanodot structure. The morphology of the titanium only depends on the molecular weight of the block copolymer, which results in a remarkable fabrication technique that saves time relative to conventional methods. Analyses using scanning electron microscopy, X-ray reflectometry, and grazing-incidence small-angle X-ray scattering correlate the morphology of the titanium with the buried polymer structure. The mesoporous titanium film exhibited a pore size of approximately 16 nm, with a pore-to-pore distance of 42 nm. The average size of the hexagonally packed nanodots was 60 nm, with a center-to-center distance of 88 nm commensurate with the template features. An analysis of the chemical composition showed that the structures were titanium dioxide, which indicated that oxidation occurred during the fabrication process.The authors acknowledge financial support from the EU-FP7 Integrated Infrastructure Initiative No. 262348 from the European Soft Matter Infrastructure (ESMI), LAMAND (Grant No. 245565), MERGING (Grant No. 309150), the Spanish MINECO project TAPHOR (MAT2012−31392), and the Deutsche Forschungsgemeinschaft (Grant No. KR 4522/1-1).Peer Reviewe