| 1. |
- Beck, Marc
(författare)
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Development of Nanoimprint Lithography for Fabrication of Electrochemical Transducers
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis gives an overview about the current status of nanoimprint lithography, a relatively new nanofabrication tool. The technology is capable for parallel mass production of nm-structured features having a resolution below 10 nm and is usable with high throughput on full wafer scale. The thesis is mainly divided into two parts dealing with nanoimprint lithography and electrochemistry. The work concerns the development of reliable and reproducible imprint processes, e.g. for fabrication of nm-structured interdigitated array electrodes usable in (bio-) electrochemical sensor applications. Such electrodes can be used for measuring electrochemical processes such as redox cycling, which become addressable when the electrode distance becomes smaller than the diffusion layer thickness at the electrode/electrolyte interface. The process development addresses several issues such as: (i) Production of nanoimprint stamps/molds with electron beam and UV-lithography. (ii) Evaluation of new polymers especially developed for nanoimprint lithography. (iii) Anti-adhesion treatment of different imprint molds with molecular layers and (iv) their characterization with photoelectron spectroscopy. (v) Development of post-imprint processes for substrate etching or metal lift-off. (vi) Deposition of non-corroding alternative organic adhesion promoters for gold on silicon dioxide. (vii) Evaluation of fluorescence microscopy as a tool for quality control in industrial nanoimprint processes. The electrochemistry part deals mainly with theoretical electrochemistry as we teach it in the biophysics course given at the department and is supposed to be used as course literature. Parallel to the NIL process development electrochemical equipment was built and evaluated with some standard measurements presented in this thesis. The outcome of this development was used to build a more advanced instrument suitable for redox cycling with nm-structured electrodes. First results with nm-structured electrodes are compared with mm-structured ones.
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| 2. |
- Beck, Marc, et al.
(författare)
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Fabrication and characterization of a molecular adhesive layer for micro- and nanofabricated electrochemical electrodes
- 2002
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Ingår i: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
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Konferensbidrag (refereegranskat)abstract
- When making nanoelectrodes for applications in liquid cells it is plausible that the less noble metal layer may be negatively affected, i.e. it will be etched away leading to very unstable conditions during operation. Here we describe a dry method to produce such a molecular layer consisting of mercaptopropyltriethoxysilane (MPTS) making it possible to controllable and reproducibly form a covalently bound monolayer of MPTS to the SiO2 surface. From Photoelectron Spectroscopy measurements we could conclude that the layer thickness corresponds to a monolayer. We have electrochemically characterized such electrodes by cyclic voltammetry. Furthermore, we have successfully patterned such layers at both micro- and nanometer scale showing the possibilities to fabricate chemically selective and active areas that may be used in various applications
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| 3. |
- Beck, Marc, et al.
(författare)
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Improving stamps for 10 nm level wafer scale nanoimprint lithography
- 2002
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Ingår i: Microelectronic Engineering. - 1873-5568. ; 61-2, s. 441-448
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Tidskriftsartikel (refereegranskat)abstract
- The smaller the features on the stamp the more important are the interactions between stamp and polymer layer. A stamp rich in small structures will effectively show a surface area enlargement, which generally leads to adhesion of the polymer to the stamp. This makes a subsequent imprint impossible without troublesome and time-consuming cleaning. The anti-adhesion properties of Si- or SiO2-based stamps can be improved by binding fluorinated silanes covalently to the surface. In this paper, we demonstrate that the deposition procedure as well as the environment during deposition are important with respect to the quality and performance of the molecular layer. (C) 2002 Published by Elsevier Science B.V.
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| 4. |
- Beck, Marc, et al.
(författare)
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Nanoelectrochemical transducers for (bio-) chemical sensor applications fabricated by nanoimprint lithography
- 2004
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Ingår i: Microelectronic Engineering. - 1873-5568. ; 73-74, s. 837-842
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Tidskriftsartikel (refereegranskat)abstract
- Nanometer-structured transducers for commercial use in pharmaceutical, medical or (bio-) chemical analysis have so far been hardly accessible since they could not be produced by parallel lithography techniques at reasonable costs. We introduce here a method on. how to fabricate nanometer-structured interdigitated array electrodes including interconnections and bond pads in the micrometer range in a single imprint step on 2-in. wafer scale. The method enables the mass production of those devices at lowest cost opening a new field for the commercial use of nanometer-structured sensor systems.
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| 5. |
- Carlberg, Patrick, et al.
(författare)
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Lift-off process for nanoimprint lithography
- 2003
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Ingår i: Microelectronic Engineering. - 1873-5568 .- 0167-9317. ; 67-8, s. 203-207
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Konferensbidrag (refereegranskat)abstract
- We report a novel a lift-off method for nanoimprint lithography. This is a bi-layer method, using a polymethyl methacrylate (PMMA) on lift-off layer (LOL) resist scheme. For the imprint step, direct evidence for good pattern transfer down to 20 nm is shown. Oxygen plasma ashing is required to remove residual PMMA. A liquid solvent, MF 319, is used to transfer the pattern down to the silicon. The LOL is dissolved isotropically while the PMMA is unaffected. Ashing time can kept to a minimum through the wet etch method. This reduces the line widening effect. After metal evaporation a two-step lift-off process prevents metal flakes from adhering to the surface electrostatically. At first warm acetone breakes apart the metal layer and dissolves the PMMA, then warm Remover S-1165 removes the LOL and remaining metal. Structures of lines down to 50 nm and dots with a diameter of sub 20 nm are presented.
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| 6. |
- Carlberg, Patrick, et al.
(författare)
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Nanoimprint - a tool for realizing nano-bio research
- 2004
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Ingår i: 2004 4th IEEE Conference on Nanotechnology. - 0780385365 ; , s. 199-200
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a status report on how implementation of nanoimprint lithography has advanced our research. Contact guidance nerve growth experiments have so far primarily been done on micrometer-structured surfaces. We have made a stamp with 17 areas of different, submicron, line width and spacing covering a total 2.6 mm
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| 7. |
- Carlberg, Patrick, et al.
(författare)
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Nanoimprint in mr-L 6000.1 XP/PMMA resist system
- 2002
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Ingår i: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
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Konferensbidrag (refereegranskat)abstract
- Use of the new resist system mr-L 6000.1 XP in combination with PMMA is demonstrated to give sub-100 nm resolution in nanoimprint lithography. Low glass transition temperature in combination with high plasma stability makes this resist suitable for achieving desirable resist profiles after the imprint process. Imprint conditions for mr-L 6000.1 XP/PMMA resist system as well as imprint results are described and discussed
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| 8. |
- Carmeliet, Peter, et al.
(författare)
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Synergism between vascular endothelial growth factor and placental growth factor contributes to angiogenesis and plasma extravasation in pathological conditions
- 2001
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 7:5, s. 575-583
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Tidskriftsartikel (refereegranskat)abstract
- Vascular endothelial growth factor (VEGF) stimulates angiogenesis by activating VEGF receptor-2 (VEGFR-2). The role of its homolog, placental growth factor (PlGF), remains unknown. Both VEGF and PlGF bind to VEGF receptor-1 (VEGFR-1), but it is unknown whether VEGFR-1, which exists as a soluble or a membrane-bound type, is an inert decoy or a signaling receptor for PlGF during angiogenesis. Here, we report that embryonic angiogenesis in mice was not affected by deficiency of PlGF (Pgf-/-). VEGF-B, another ligand of VEGFR-1, did not rescue development in Pgf-/- mice. However, loss of PlGF impaired angiogenesis, plasma extravasation and collateral growth during ischemia, inflammation, wound healing and cancer. Transplantation of wild-type bone marrow rescued the impaired angiogenesis and collateral growth in Pgf-/- mice, indicating that PlGF might have contributed to vessel growth in the adult by mobilizing bone-marrow-derived cells. The synergism between PlGF and VEGF was specific, as PlGF deficiency impaired the response to VEGF, but not to bFGF or histamine. VEGFR-1 was activated by PlGF, given that anti-VEGFR-1 antibodies and a Src-kinase inhibitor blocked the endothelial response to PlGF or VEGF/PlGF. By upregulating PlGF and the signaling subtype of VEGFR-1, endothelial cells amplify their responsiveness to VEGF during the 'angiogenic switch' in many pathological disorders.
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| 9. |
- Finder, C, et al.
(författare)
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Fluorescence microscopy for quality control in nanoimprint lithography
- 2003
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Ingår i: Microelectronic Engineering (Proceedings of the 28th International Conference on Micro- and Nano-Engineering). - 0167-9317 .- 1873-5568. ; 67-8, s. 623-628
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Konferensbidrag (refereegranskat)abstract
- Fluorescence microscopy is introduced as a low cost quality control process for nanoimprint lithography. To depict imprinted structures down to 1 mum lateral size and to detect residues down to 100 nm lateral size, the standard printable polymer mr-18000 is labelled with less than 0.1 wt.% fluorescent dye. Three different types of stamps are used to determine the dependence of the shape and size of stamp features in a series of imprints. The quality of a stamp is given by the sticking polymer residues per unit area. Fluorescence light images as well as visible light images are analysed. Changes in the area of the stamp covered with polymer as a function of the number of imprints is summarised in a statistical process chart. Adhesion was artificially induced in order to observe self cleaning of virgin stamps. They were detected and monitored, suggesting that this method is a suitable technique for quality control and that it could be easily adapted to the nanoimprint process. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 10. |
- Keil, M, et al.
(författare)
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Process development and characterization of antisticking layers on nickel-based stamps designed for nanoimprint lithography
- 2004
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Ingår i: Journal of Vacuum Science and Technology B. - : American Vacuum Society. - 1520-8567. ; 22:6, s. 3283-3287
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Tidskriftsartikel (refereegranskat)abstract
- Thin films of different derivatives of fluorinated alkyl phosphoric acids have been deposited from aqueous solutions onto surfaces of oxidized polycrystalline nickel stamps. which are commonly used in several industrial applications of nanoimprint lithography (NIL). The films have been established in order to increase the antiadhesion tendencies at the stamp polymer interface. Thicknesses, chemical compositions, and purities of the films as well as binding mechanisms to the stamp surfaces have been determined by photoelectron spectroscopy (XPS). The results demonstrate the adsorption of highly pure films having thicknesses in the monomolecular region, whose chemical compositions are characterized by large ratios of fluorinated to nonfluorinated carbon species. The high ionic nature of Ni-oxide benefits strong ionic linkages between the phosphate groups of the fluorinated antisticking film and the stamp surface, allowing a large-scale production of imprints with patterned stamps having feature sizes down to 100 nm. (C) 2004 American Vacuum Society.
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