Micro and Nano Engineering最新文献

{"title":"Near-collector electroprinting of cellulose acetate structures with large specific surface per volume","authors":"Farnaz Rezaei ,&nbsp;Daniel O. Carlsson ,&nbsp;Jimmy Hedin Dahlstrom ,&nbsp;Jonas Lindh ,&nbsp;Stefan Johansson","doi":"10.1016/j.mne.2025.100299","DOIUrl":"10.1016/j.mne.2025.100299","url":null,"abstract":"<div><div>This study focuses on the fabrication and analysis of 3D-printed high-detail resolution cellulose acetate (CA) structures, particularly examining their specific surface area per volume <span><math><mfenced><msub><mi>S</mi><mi>v</mi></msub></mfenced></math></span>. While electrospinning is a widely used technique for creating nanofiber membranes with high <span><math><msub><mi>S</mi><mi>v</mi></msub></math></span>, which is advantageous for applications like chromatography, the performance could be further improved by precisely controlling fiber placement. To further develop membranes, this research explores the use of electroprinting with small distances between nozzle and collector, here named near-collector electroprinting, to create 3D structures. By optimizing printing parameters, in particular the reduction of the nozzle-to-collector distance, 3D structures with precise fiber placement within a few micrometers were fabricated. The specific surface area per volume was calculated for both 3D-printed and electrospun filters. Results showed that 3D-printed structures with a 5 μm pitch achieved a <span><math><msub><mi>S</mi><mi>v</mi></msub></math></span> similar to electrospun filters.</div><div>Incorporating polyethyleneimine (PEI) in the CA ink enabled the 3D-printed structures to gain ion binding capacity which was further investigated. This ion-exchange ability which integrated into the printing step, eliminating the need for a separate post-modification process in bio-separation applications. By switching the substrate voltage from positive to negative, relative to the grounded nozzle, the printed fiber diameter decreased substantially for the CA ink with PEI. The <span><math><msub><mi>S</mi><mi>v</mi></msub></math></span> for near-collector electroprinted fibers of this material could therefore potentially be higher than that of electrospun membranes, provided that an order of magnitude higher printing speed, than presently possible can be used. These findings suggest that near-collector electroprinted CA structures offer potential improvements in membrane design and performance, making them a promising alternative to traditional electrospun membranes for bio-separation applications.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"27 ","pages":"Article 100299"},"PeriodicalIF":2.8,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasonic power and data transfer for active medical implants using adaptive beamforming","authors":"Tianhui Li ,&nbsp;James A. Flint ,&nbsp;Hailing Fu ,&nbsp;Sotiris Korossis ,&nbsp;Stephanos Theodossiades","doi":"10.1016/j.mne.2025.100296","DOIUrl":"10.1016/j.mne.2025.100296","url":null,"abstract":"<div><div>Wireless power transfer provides a sustainable power source for active medical implants. Recent developments in biosensors, MEMS technologies and the advent of ubiquitous computing has opened up the potential for a millimeter-sized active medical implant for continuous health monitoring. Frequent wireless communication and data processing requires more energy than traditional active medical implants. Therefore, a continuous power source is needed. This study investigated the development of an ultrasonic power transfer (USPT) system for active medical implants. The system, comprised of a wearable and an implantable device, can transfer both power and data between the implant and the wearable. By implementing beamforming, it can adapt to misalignment between the transmitter and the receiver. In the experiments, the receiver outputs 0.16 mW after rectification, when transmitting through 0.5 cm of water. By measuring the time-of-flight (ToF) of a pulse transmitted from the receiver, implant position feedback is achieved. Data transfer is demonstrated at a rate of 1 kbit/s, across a 4 cm path in water, which is adequate for many biomedical applications.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"27 ","pages":"Article 100296"},"PeriodicalIF":2.8,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regional proximity effect correction for replicating 28 nm lines/spaces in HSQ as dielectric diffraction gratings with high aspect ratio","authors":"Qingxin Wu ,&nbsp;Wentao Yuan ,&nbsp;Qiucheng Chen ,&nbsp;Hao Quan ,&nbsp;Yifang Chen","doi":"10.1016/j.mne.2025.100295","DOIUrl":"10.1016/j.mne.2025.100295","url":null,"abstract":"<div><div>With the rapid advances of extreme ultraviolet (EUV) lithography toward ultra-high resolution, characterization technique of EUV resists by interference lithography (IL) for 14-nm node process needs urgent upgrading because of the considerable loss of light transmission by metallic grating masks. Diffraction phase gratings in dielectric silicon dioxide as masks are a promising solution, provided that 28 nm lines/spaces with high aspect ratio as well as large grating areas are obtained. This paper reports our recent success in replicating 28 nm half-pitch gratings with the aspect ratio of 13:1 and the area up to 200 × 200 μm² by state-of-the-art electron beam lithography with regional proximity effect correction (PEC) in hydrogen silsesquioxane (HSQ) coated on a 100 nm silicon nitride membrane. To ensure well resolved lines/spaces in 350 nm thick HSQ, Monte Carlo algorithm is applied in the simulations of 3D absorbing electron energy density distributions, followed by calculations of equal energy contours of deposited energy based on the kinetic development model, which enables us to work out reliable dose windows. The process developed in this work should be feasibly extended to large area gratings in a future industrialization.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"26 ","pages":"Article 100295"},"PeriodicalIF":2.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Understanding dose correction for high-resolution 50 kV electron-beam lithography on thick resist layers” [Micro and Nano Engineering Volume 16, August 2022, 100141]","authors":"Mattias Åstrand,&nbsp;Thomas Frisk,&nbsp;Hanna Ohlin,&nbsp;Ulrich Vogt","doi":"10.1016/j.mne.2025.100297","DOIUrl":"10.1016/j.mne.2025.100297","url":null,"abstract":"","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"26 ","pages":"Article 100297"},"PeriodicalIF":2.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143941511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid prototyping of 3D microstructures: A simplified grayscale lithography encoding method using blender","authors":"Fabrício Frizera Borghi ,&nbsp;Mohammed Bendimerad ,&nbsp;Marie-Ly Chapon ,&nbsp;Tatiana Petithory ,&nbsp;Laurent Vonna ,&nbsp;Laurent Pieuchot","doi":"10.1016/j.mne.2024.100294","DOIUrl":"10.1016/j.mne.2024.100294","url":null,"abstract":"<div><div>The democratization of fabrication equipment has spurred recent interest in maskless grayscale lithography for both 2D and 3D microfabrication. However, the design of suitable template images remains a challenge. This work presents a simplified method for encoding 3D objects into grayscale image files optimized for grayscale lithography. Leveraging the widely used and open-source 3D modeling software Blender, we developed a robust approach to convert geometric heights into grayscale levels and generate image files through top-view rendering. Our method accurately reproduced the overall shape of simple structures like stairs and ramps compared to the original designs. We extended this approach to complex 3D sinusoidal surfaces, achieving similar results. Given the increasing accessibility and user-friendliness of digital rendering tools, this study offers a promising strategy for rapid prototyping of initial designs with minimal effort.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"26 ","pages":"Article 100294"},"PeriodicalIF":2.8,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pattern distortion in nanoimprint lithography using UV-curable polymer stamps","authors":"Fangfang Li ,&nbsp;Marina Fetisova ,&nbsp;Mervi Koskinen ,&nbsp;Jukka Viheriälä ,&nbsp;Tapio Niemi ,&nbsp;Petri Karvinen ,&nbsp;Markku Kuittinen","doi":"10.1016/j.mne.2024.100293","DOIUrl":"10.1016/j.mne.2024.100293","url":null,"abstract":"<div><div>Quantification of pattern distortion in nanoimprint lithography (NIL) is required when applying it to specific applications, especially those with tight tolerances. We present a systematic study on full wafer NIL distortion using soft stamps made of different carrier foils and UV-curable polymer structure layers. These errors are evaluated by overlay patterning using NIL and optical lithography on 4-in. wafers over a distance of 80 mm. Potential causes for pattern distortion and possible correction methods are discussed in terms of stamp composition and environmental impact. Pattern distortion along axes causing dimensional change is stamp dependent, and stiffer stamps show less pattern dimensional change than the softer ones. In the best case, the minimum variation is 4 parts per million (ppm), and in the worst case, 252 ppm with a softer stamp. Stamp flatness and uniform contact during imprinting are important in reducing high-order pattern distortion. A maximum dimensional variation of 32 ppm in a batch run demonstrates good pattern repeatability. Long-term dimensional stability can be affected by relative humidity, with variations on the order of 100 ppm.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"25 ","pages":"Article 100293"},"PeriodicalIF":2.8,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ measurements of thermal and pressure dependent stress in SOG films by phase shifting interferometry","authors":"T.M. van den Berg,&nbsp;A. Bosseboeuf,&nbsp;P. Coste,&nbsp;L. Vincent","doi":"10.1016/j.mne.2024.100292","DOIUrl":"10.1016/j.mne.2024.100292","url":null,"abstract":"<div><div>Hydrogen silsesquioxane (HSQ) and Medusa are spin-on-glasses used for several applications and more specifically for electron-beam lithography. To characterize the thermal densification of these resists on silicon, the mean resist film stress was measured in situ as function of temperature up to 600 °C in a vacuum chamber by the curvature method. The curvature was evaluated from 3D profiles of uncoated and coated dies measured by full field phase shifting interferometry. Three resists were investigated: FOx-15, FOx-25 and Medusa-82. The initial resist stress at room temperature after spin coating and baking is slightly tensile and becomes highly tensile above a certain temperature dependent on the resist. This variation is mainly attributed to resists densification. FOx-15 and FOx-25 start densifying at 500 °C, and FOx-25 densifies more than FOx-15. Medusa-82 is densifying around 300 °C and has the highest tensile stress but the film relaxes beyond 405 °C. In the case of FOx-15, it was found that vacuum annealing prevents densification. Finally, we evaluated the in-plane average coefficient of thermal expansion of the resists from stress measurements during cooling to room temperature. For FOx-15, a CTE equal to 1.5 ppm/K is found, while it is close to 0.0±0.2 ppm/K for FOx-25 and 1.3 ppm/K for Medusa-82.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"25 ","pages":"Article 100292"},"PeriodicalIF":2.8,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser-engraved holograms as entropy source for random number generators","authors":"Christos Tselios ,&nbsp;Anastasios Tsakas ,&nbsp;Simone Mazzucato ,&nbsp;Christina Politi (Tanya) ,&nbsp;Panagiotis Rizomiliotis ,&nbsp;Dimitris Alexandropoulos","doi":"10.1016/j.mne.2024.100290","DOIUrl":"10.1016/j.mne.2024.100290","url":null,"abstract":"<div><div>Our study introduces a novel approach to true random number generation (TRNG) using speckle patterns generated by laser-engraved holograms on carbon fiber-reinforced polymer (CFRP) composite substrates. Unlike previous methods, our approach simplifies the process by generating the necessary image dataset from a single microscope image of the engraved hologram. We achieve a high extraction ratio of 76 %, demonstrating the effectiveness of our TRNG. Moreover, our method successfully passes rigorous statistical tests proposed by the National Institute of Standards and Technology (NIST), indicating its suitability for cryptographic and secure system applications. This work offers promising implications for enhancing security in various domains, from secure communication networks to IoT devices.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"25 ","pages":"Article 100290"},"PeriodicalIF":2.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Release of hydrogen gas from PECVD silicon nitride thin films in cavities of MEMS sensors","authors":"P. Dani ,&nbsp;M. Tuchen ,&nbsp;B.E. Meli ,&nbsp;J. Franz ,&nbsp;J. Knoch","doi":"10.1016/j.mne.2024.100291","DOIUrl":"10.1016/j.mne.2024.100291","url":null,"abstract":"<div><div>In this work we investigate the release of hydrogen gas from PECVD silicon nitride thin films in the cavities of MEMS based inertial sensors. Firstly, material characterization is conducted on two types of PECVD silicon nitride thin films to study the release of hydrogen gas with analytical methods. The release of hydrogen gas from these materials in encapsulated cavities of MEMS sensors, and its influence on the cavity pressure is also investigated experimentally with the help of functional microchips of MEMS based inertial sensors. Based on our findings and reports from other works, we propose steps by which change in the cavity pressure of the investigated microchip occurs over its different fabrication processes. We suggest that hydrogen gas is released form PECVD silicon nitride thin films at high temperatures during wafer bonding, which can then diffuse in cavities at low pressure over the lifetime of the sensor.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"25 ","pages":"Article 100291"},"PeriodicalIF":2.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developments in the design and microfabrication of photovoltaic retinal implants","authors":"Pratik Kusumanchi ,&nbsp;Stephan Sylvest Keller ,&nbsp;Rasmus Schmidt Davidsen","doi":"10.1016/j.mne.2024.100289","DOIUrl":"10.1016/j.mne.2024.100289","url":null,"abstract":"<div><div>Photovoltaic retinal implants are emerging as a promising technological solution for restoring vision for patients suffering from retinal degenerative diseases such as retinitis pigmentosa and age-related macular degeneration. These prostheses contain arrays of miniaturized solar cells converting light into electrical output signals, which subsequently are employed for local activation of the intact neuroretina via microelectrodes. Leveraging cutting-edge microfabrication techniques, photovoltaic retinal implants are compact and provide a high density of solar cell pixels. This potentially increases the resolution of the artificial vision and the field of view and lowers the threshold for stimulation of retinal neurons. The introduction of flexible substrates and the integration of 3D electrodes has greatly improved the connection with retinal neurons, optimizing the spatial resolution and potentially lowering the stimulation threshold. This review explores the latest developments in photovoltaic retinal prostheses, highlighting key aspects of their design, fabrication and performance. This field of research is still in its early stage and particular emphasis is laid on promising future research directions including miniaturization of pixels, incorporation of organic flexible semiconductors and first studies considering 3D stimulating electrode structures. Despite the significant progress made, there are still substantial challenges to overcome, such as ensuring long-term biocompatibility and validation of the novel concepts in clinical trials. Ongoing interdisciplinary research and development are essential for moving these promising technologies from the lab to real-world clinical applications, ultimately enhancing vision restoration. This review aims to provide a comprehensive overview of the current state of photovoltaic retinal implants and pinpoints critical areas for future research to further advance this transformative technology.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"25 ","pages":"Article 100289"},"PeriodicalIF":2.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}