The behavior of molten glass on nanostructured silicon surface is of essential importance for the fabrication of a strong bond interface between glass （or glass-based ceramic tapes） and silicon. It was found that ty...The behavior of molten glass on nanostructured silicon surface is of essential importance for the fabrication of a strong bond interface between glass （or glass-based ceramic tapes） and silicon. It was found that typical glasses do not wet the silicon surface that is always coated with a thin silica layer. It is shown that the high surface tension of molten glasses at high temperatures in combination with the dewetting surface of the structured silicon prohibits the formation of an interlocking bond between the two substrates. The theory of wetting can be applied to molten glasses, too. As a consequence, a similar solution as for liquids is investigated： the surface has to be chemically modified to become wettable. Investigations with sputtered metals on the nanostructured silicon improve wetting of the surface and result in a better bond homogeneity of the SiCer compound during sintering with low pressure.展开更多
In this paper,an electrostatic compliant mechanical amplifier intended for force-compensated displacement amplification in MEMS sensor applications is described.Usually,mechanical transformers that enhance a small inp...In this paper,an electrostatic compliant mechanical amplifier intended for force-compensated displacement amplification in MEMS sensor applications is described.Usually,mechanical transformers that enhance a small input displacement into a large output displacement generate large forces at the input of the transformer.The microsystem proposed here allows for the reduction and compensation of the input stiffness of the amplifier and any mechanical components connected to it while providing a constant amplification ratio at the same time.The amplifying mechanism features bidirectional electrostatic anti-springs enabling the control of the stiffness by applying a constant DC voltage.The electrode design of the anti-springs and its influence on the force-displacement characteristic,the side instability and the maximal displacement are studied through analytical approaches and supported by FEA and by experiments.Based on the derived models,a compliant electromechanical amplifier is developed,featuring an amplification ratio of 50.For this amplifier the initial input stiffness of 422 N/m could be reduced to 6.8 N/m by applying a voltage of 100 V.As an additional application,we show how the amplifier can be used as a mechanical force sensor with tuneable sensitivity,where the forces at the input are transformed into large output displacements.Through experiments,we show how the sensitivity can be adjusted and increased by a factor of 25 by applying a voltage at the anti-springs.展开更多
Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL to...Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL tool and its integration into a nanopositioning and nanomeasuring machine to achieve high-precision orthogonal molding and demolding for soft ultraviolet-assisted NIL(soft UV-NIL).The process was implemented primarily on the edges of highly curved plano-convex substrates to demonstrate structure uniformity on the edges.High-resolution nanostructures of sub-200-nm lateral dimension and microstructures in the range of tens of microns were imprinted.However,the nanostructures on the edges of the large,curved substrates were difficult to characterize precisely.Therefore,microstructures were used to measure the structure fidelity and were characterized using profilometry,white light interferometry,and confocal laser scanning microscopy.Regardless of the restricted imaging capabilities at high inclinations for high-resolution nanostructures,the scanning electron microscope(SEM)imaging of the structures on top of the lens substrate and at an inclination of 45°was performed.The micro and nanostructures were successfully imprinted on the edges of the plano-convex lens at angles of 45°,60°,and 90°from the center of rotation of the rotating NIL tool.The method enables precise imprinting at high inclinations,thereby presenting a different approach to soft UV-NIL on curved surfaces.展开更多
文摘The behavior of molten glass on nanostructured silicon surface is of essential importance for the fabrication of a strong bond interface between glass （or glass-based ceramic tapes） and silicon. It was found that typical glasses do not wet the silicon surface that is always coated with a thin silica layer. It is shown that the high surface tension of molten glasses at high temperatures in combination with the dewetting surface of the structured silicon prohibits the formation of an interlocking bond between the two substrates. The theory of wetting can be applied to molten glasses, too. As a consequence, a similar solution as for liquids is investigated： the surface has to be chemically modified to become wettable. Investigations with sputtered metals on the nanostructured silicon improve wetting of the surface and result in a better bond homogeneity of the SiCer compound during sintering with low pressure.
基金This work has been funded by the German Federal Ministry of Education and Research under contract 16ES1063(ForMikro-upFUSE).The authors thank Matthias Paul Kroll for his support with the measurements in the cleanroom.The microsystems were partly fabricated with etching equipment provided by the Center for Interface-Dominated High-Performance Materials(ZGH).We acknowldege support by the Open Access Publication Funds of the Ruhr-Universität Bochum.
文摘In this paper,an electrostatic compliant mechanical amplifier intended for force-compensated displacement amplification in MEMS sensor applications is described.Usually,mechanical transformers that enhance a small input displacement into a large output displacement generate large forces at the input of the transformer.The microsystem proposed here allows for the reduction and compensation of the input stiffness of the amplifier and any mechanical components connected to it while providing a constant amplification ratio at the same time.The amplifying mechanism features bidirectional electrostatic anti-springs enabling the control of the stiffness by applying a constant DC voltage.The electrode design of the anti-springs and its influence on the force-displacement characteristic,the side instability and the maximal displacement are studied through analytical approaches and supported by FEA and by experiments.Based on the derived models,a compliant electromechanical amplifier is developed,featuring an amplification ratio of 50.For this amplifier the initial input stiffness of 422 N/m could be reduced to 6.8 N/m by applying a voltage of 100 V.As an additional application,we show how the amplifier can be used as a mechanical force sensor with tuneable sensitivity,where the forces at the input are transformed into large output displacements.Through experiments,we show how the sensitivity can be adjusted and increased by a factor of 25 by applying a voltage at the anti-springs.
基金the support by the Deutsche Forschungsgemeinschaft(DFG)in the framework of the Research Training Group Tip and Laser-based 3D-Nanofabrication in extended macroscopic working areas(GRK 2182)at the Technische Universitat Ilmenau,Germany.
文摘Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL tool and its integration into a nanopositioning and nanomeasuring machine to achieve high-precision orthogonal molding and demolding for soft ultraviolet-assisted NIL(soft UV-NIL).The process was implemented primarily on the edges of highly curved plano-convex substrates to demonstrate structure uniformity on the edges.High-resolution nanostructures of sub-200-nm lateral dimension and microstructures in the range of tens of microns were imprinted.However,the nanostructures on the edges of the large,curved substrates were difficult to characterize precisely.Therefore,microstructures were used to measure the structure fidelity and were characterized using profilometry,white light interferometry,and confocal laser scanning microscopy.Regardless of the restricted imaging capabilities at high inclinations for high-resolution nanostructures,the scanning electron microscope(SEM)imaging of the structures on top of the lens substrate and at an inclination of 45°was performed.The micro and nanostructures were successfully imprinted on the edges of the plano-convex lens at angles of 45°,60°,and 90°from the center of rotation of the rotating NIL tool.The method enables precise imprinting at high inclinations,thereby presenting a different approach to soft UV-NIL on curved surfaces.
