Pub Date : 2025-09-01DOI: 10.1016/j.mne.2025.100319
S. Schermer , J. Bieling , S. DeMoor , A. Zanzal , P. Reynolds , C. Helke , J. Bonitz , A. Voigt , D. Reuter
In this work a reticle based i-line projection grayscale stepper lithography is applied, the patterning results are analyzed and the lithographic process is optimized to obtain low surface roughness grayscale pattern. Here the low contrast resist ma-P 1211G, one type of the ma-P 1200G grayscale resist series, from micro resist technology and tailored grayscale reticles from benchmark technologies are used. The spin curve, contrast curve and layer homogeneity of the resist were measured. A low surface roughness of the generated grayscale structures is important, because the roughness will be transferred during subsequent etching steps as pattern transfer. The impact of the pixel size (within the reticle) on the resist roughness and structure fidelity after resist development was investigated. Therefore, to measure the roughness of exposed and developed structures by AFM, dedicated roughness pads were integrated into the reticle design. After evaluation of the resist roughness a DOE study for different annealing steps in order to smoothen the resist surface after development was conducted. The ideal annealing or smoothening temperature was determined to reduce the resist roughness and preserve/ retain the structure fidelity at the same time.
{"title":"Optimizing reticle based high throughput i-line grayscale projection lithography for 3D structures with low surface roughness","authors":"S. Schermer , J. Bieling , S. DeMoor , A. Zanzal , P. Reynolds , C. Helke , J. Bonitz , A. Voigt , D. Reuter","doi":"10.1016/j.mne.2025.100319","DOIUrl":"10.1016/j.mne.2025.100319","url":null,"abstract":"<div><div>In this work a reticle based i-line projection grayscale stepper lithography is applied, the patterning results are analyzed and the lithographic process is optimized to obtain low surface roughness grayscale pattern. Here the low contrast resist ma-P 1211G, one type of the ma-P 1200G grayscale resist series, from micro resist technology and tailored grayscale reticles from benchmark technologies are used. The spin curve, contrast curve and layer homogeneity of the resist were measured. A low surface roughness of the generated grayscale structures is important, because the roughness will be transferred during subsequent etching steps as pattern transfer. The impact of the pixel size (within the reticle) on the resist roughness and structure fidelity after resist development was investigated. Therefore, to measure the roughness of exposed and developed structures by AFM, dedicated roughness pads were integrated into the reticle design. After evaluation of the resist roughness a DOE study for different annealing steps in order to smoothen the resist surface after development was conducted. The ideal annealing or smoothening temperature was determined to reduce the resist roughness and preserve/ retain the structure fidelity at the same time.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100319"},"PeriodicalIF":3.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004270","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}
Pub Date : 2025-08-23DOI: 10.1016/j.mne.2025.100316
Mario Bähr , Björn Gojdka , Thomas Lisec , Niels Clausen , Mani Teja Bodduluri , Aya Zino , Indira Käpplinger , Dominik Karolewski , Jan Meijer , Thomas Ortlepp
The implementation of PowderMEMS® micromagnets of varying shapes, with lateral dimensions of 700 μm and 800 μm, into 2.3 × 2.3 × 0.525 mm3 silicon chips has been demonstrated successfully. These chips have been utilized as functionalized interposer for micro-scaled quantum devices. PowderMEMS® micromagnets offer a high biasing magnetic field flux density ranging from 30 mT to 35 mT over a distance of 100 μm depending on the size and shape of the micromagnets. This magnetic field strength (BZ) was proven by room temperature ODMR measurements with NV centers in diamond: BZ was measured over a range of distances, extending to 6 mm from the center of the micromagnets. The evaluation involved the analysis of Zeeman splitting. Furthermore, a Hall measurement setup was employed to map the lateral distribution of the magnetic field strength.
{"title":"PowderMEMS® magnets as enabler for miniaturized NV based quantum sensors and quantum processor architectures","authors":"Mario Bähr , Björn Gojdka , Thomas Lisec , Niels Clausen , Mani Teja Bodduluri , Aya Zino , Indira Käpplinger , Dominik Karolewski , Jan Meijer , Thomas Ortlepp","doi":"10.1016/j.mne.2025.100316","DOIUrl":"10.1016/j.mne.2025.100316","url":null,"abstract":"<div><div>The implementation of PowderMEMS® micromagnets of varying shapes, with lateral dimensions of 700 μm and 800 μm, into 2.3 × 2.3 × 0.525 mm<sup>3</sup> silicon chips has been demonstrated successfully. These chips have been utilized as functionalized interposer for micro-scaled quantum devices. PowderMEMS® micromagnets offer a high biasing magnetic field flux density ranging from 30 mT to 35 mT over a distance of 100 μm depending on the size and shape of the micromagnets. This magnetic field strength (<em>B</em><sub>Z</sub>) was proven by room temperature ODMR measurements with NV centers in diamond: <em>B</em><sub>Z</sub> was measured over a range of distances, extending to 6 mm from the center of the micromagnets. The evaluation involved the analysis of Zeeman splitting. Furthermore, a Hall measurement setup was employed to map the lateral distribution of the magnetic field strength.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100316"},"PeriodicalIF":3.1,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895448","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}
Pub Date : 2025-08-11DOI: 10.1016/j.mne.2025.100315
A. Kondi , E.-M. Papia , V. Constantoudis , D. Nioras , I. Syngelakis , C. Aivalioti , E. Aperathitis , E. Gogolides
This work introduces a computational method to quantify the thickness of thin films deposited on highly rough substrates analyzing top-down Scanning Electron Microscope (SEM) images. The method entails measuring the bright areas of top-down SEM images of the rough surface obtained before and after deposition, allowing for the prediction of film thickness through the ratio of bright area enhancement caused by deposition to the average perimeter of these areas before and after deposition. Validation of this technique was conducted via synthetic SEM images with predefined film thicknesses, incorporating simple and complex substrate morphologies generated through Diffusion-Limited Aggregation (DLA) simulations for added realism. Experimental applications were explored through the analysis of SEM images of plasma-etched polymer (PMMA) surfaces coated with carbyne and of nanorods of TiO2 coated with NiO, demonstrating the method's efficacy across varying surface roughness and morphologies. This work lays the foundation for future advancements, including the implementation of a neural network trained on synthetic datasets to enhance the measurement accuracy of coating thickness on rough substrates as well as the reconstruction of true surface morphologies prior to metal layer sputtering via SEM image analysis.
{"title":"Measurement of thickness of thin coatings on rough substrates via computational analysis of SEM images","authors":"A. Kondi , E.-M. Papia , V. Constantoudis , D. Nioras , I. Syngelakis , C. Aivalioti , E. Aperathitis , E. Gogolides","doi":"10.1016/j.mne.2025.100315","DOIUrl":"10.1016/j.mne.2025.100315","url":null,"abstract":"<div><div>This work introduces a computational method to quantify the thickness of thin films deposited on highly rough substrates analyzing top-down Scanning Electron Microscope (SEM) images. The method entails measuring the bright areas of top-down SEM images of the rough surface obtained before and after deposition, allowing for the prediction of film thickness through the ratio of bright area enhancement caused by deposition to the average perimeter of these areas before and after deposition. Validation of this technique was conducted via synthetic SEM images with predefined film thicknesses, incorporating simple and complex substrate morphologies generated through Diffusion-Limited Aggregation (DLA) simulations for added realism. Experimental applications were explored through the analysis of SEM images of plasma-etched polymer (PMMA) surfaces coated with carbyne and of nanorods of TiO<sub>2</sub> coated with NiO, demonstrating the method's efficacy across varying surface roughness and morphologies. This work lays the foundation for future advancements, including the implementation of a neural network trained on synthetic datasets to enhance the measurement accuracy of coating thickness on rough substrates as well as the reconstruction of true surface morphologies prior to metal layer sputtering via SEM image analysis.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100315"},"PeriodicalIF":3.1,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144830655","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}
Pub Date : 2025-08-10DOI: 10.1016/j.mne.2025.100314
Sofien Ramos , Victor Fabre , Mathieu Arribat , Aurélie Lecestre , Adrian Laborde , Frank Carcenac , Philippe Louarn , Emmanuelle Trevisiol , Christophe Vieu
Self-assembled silicon nanopillars decorated with metallic nanoparticles have emerged as efficient Surface Enhanced Raman Spectroscopy (SERS) substrates. In this study, we combine black Silicon Reactive Ion Etching-Inductively Coupled Plasma (RIE-ICP) and thin film deposition of Silver (Ag) to produce this type of surface equipped with plasmonic nano-antennas. The paper describes a quantitative methodology for optimizing the fabrication process of such silicon SERS supports and specifically the determination of the nominal thickness of the Ag thin film, that upon fragmentation at the surface of the black‑silicon nanopillars, forms Ag nanoparticles capable of enhancing the local electromagnetic field. This parameter is crucial for tuning the surface density of generated hot spots on the surface and their electromagnetic enhancement factors. We propose a methodology based on the generation of hierarchical superhydrophobic fluidic concentrators and the development of a home-made algorithm for analyzing SERS spectra of Rhodamine B (RhB) solution at sub-femtomolar concentrations. The developed hierarchical clustering algorithm automatically selects from all the spectra acquired on the region of interest, the surface enhanced spectra containing at least three vibrational Raman signatures of RhB. The objective criterion for optimizing the fabrication process or for evaluating the performance of any SERS substrate is then simply the total number of RhB spectra finally retained by the algorithm. We detail the fabrication processes, the algorithmic method and through its experimental implementation we show how to tune the parameters of the algorithm for selecting the optimal Ag thin-film thickness.
{"title":"Nanofabrication of superhydrophobic fluidic concentrators coupled with metallic plasmonic nano-antennas for SERS analysis in the sub-femtomolar range","authors":"Sofien Ramos , Victor Fabre , Mathieu Arribat , Aurélie Lecestre , Adrian Laborde , Frank Carcenac , Philippe Louarn , Emmanuelle Trevisiol , Christophe Vieu","doi":"10.1016/j.mne.2025.100314","DOIUrl":"10.1016/j.mne.2025.100314","url":null,"abstract":"<div><div>Self-assembled silicon nanopillars decorated with metallic nanoparticles have emerged as efficient Surface Enhanced Raman Spectroscopy (SERS) substrates. In this study, we combine black Silicon Reactive Ion Etching-Inductively Coupled Plasma (RIE-ICP) and thin film deposition of Silver (Ag) to produce this type of surface equipped with plasmonic nano-antennas. The paper describes a quantitative methodology for optimizing the fabrication process of such silicon SERS supports and specifically the determination of the nominal thickness of the Ag thin film, that upon fragmentation at the surface of the black‑silicon nanopillars, forms Ag nanoparticles capable of enhancing the local electromagnetic field. This parameter is crucial for tuning the surface density of generated hot spots on the surface and their electromagnetic enhancement factors. We propose a methodology based on the generation of hierarchical superhydrophobic fluidic concentrators and the development of a home-made algorithm for analyzing SERS spectra of Rhodamine B (RhB) solution at sub-femtomolar concentrations. The developed hierarchical clustering algorithm automatically selects from all the spectra acquired on the region of interest, the surface enhanced spectra containing at least three vibrational Raman signatures of RhB. The objective criterion for optimizing the fabrication process or for evaluating the performance of any SERS substrate is then simply the total number of RhB spectra finally retained by the algorithm. We detail the fabrication processes, the algorithmic method and through its experimental implementation we show how to tune the parameters of the algorithm for selecting the optimal Ag thin-film thickness.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100314"},"PeriodicalIF":3.1,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879763","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}
Pub Date : 2025-08-06DOI: 10.1016/j.mne.2025.100312
Feng-Lin Tsao , Tzu-Yu Lin , Chen Shuai , Tzu-Chun Lo , Yu-Heng Hung , Chun-Hung Lin
As feature sizes in semiconductor manufacturing continue to shrink, accurate mask inspection and wafer-level prediction have become increasingly challenging. This paper presents a lithography-driven mask reconstruction framework that infers physically meaningful mask patterns from aerial images captured by mask reviewers. The proposed approach is grounded in an image formation model based on stacked pupil shift matrices and ensures physical interpretability and alignment with real lithography processes. The framework integrates a level-set-based inverse modeling approach with adaptive time-step optimization methods, including Barzilai–Borwein method and Golden Section Search, to ensure convergence efficiency and stability. To address the sensitivity of level-set methods to initialization, a deep learning-based model trained on lithography-aware data is introduced to generate accurate initial level-set functions. Additionally, an upsampling technique is employed to overcome pixel resolution limitations and to refine mask edge smoothness without increasing runtime. Experimental results demonstrate that the reconstructed masks generate aerial images that closely match those from mask reviewers. Compared with the sidelobe search, our AI-initialized method substantially improves reconstruction accuracy and convergence, especially in cases involving subresolution assist features. Furthermore, wafer-level evaluations exhibit strong alignment between simulated and actual CD variations, and matching slopes are consistently above 0.8. The proposed framework effectively bridges the gap between aerial image analysis and wafer behavior prediction, and offers a robust, scalable solution for advanced mask review and verification workflows.
{"title":"AI-initialized level-set inversion for lithographic mask reconstruction","authors":"Feng-Lin Tsao , Tzu-Yu Lin , Chen Shuai , Tzu-Chun Lo , Yu-Heng Hung , Chun-Hung Lin","doi":"10.1016/j.mne.2025.100312","DOIUrl":"10.1016/j.mne.2025.100312","url":null,"abstract":"<div><div>As feature sizes in semiconductor manufacturing continue to shrink, accurate mask inspection and wafer-level prediction have become increasingly challenging. This paper presents a lithography-driven mask reconstruction framework that infers physically meaningful mask patterns from aerial images captured by mask reviewers. The proposed approach is grounded in an image formation model based on stacked pupil shift matrices and ensures physical interpretability and alignment with real lithography processes. The framework integrates a level-set-based inverse modeling approach with adaptive time-step optimization methods, including Barzilai–Borwein method and Golden Section Search, to ensure convergence efficiency and stability. To address the sensitivity of level-set methods to initialization, a deep learning-based model trained on lithography-aware data is introduced to generate accurate initial level-set functions. Additionally, an upsampling technique is employed to overcome pixel resolution limitations and to refine mask edge smoothness without increasing runtime. Experimental results demonstrate that the reconstructed masks generate aerial images that closely match those from mask reviewers. Compared with the sidelobe search, our AI-initialized method substantially improves reconstruction accuracy and convergence, especially in cases involving subresolution assist features. Furthermore, wafer-level evaluations exhibit strong alignment between simulated and actual CD variations, and matching slopes are consistently above 0.8. The proposed framework effectively bridges the gap between aerial image analysis and wafer behavior prediction, and offers a robust, scalable solution for advanced mask review and verification workflows.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100312"},"PeriodicalIF":3.1,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810657","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}
Pub Date : 2025-08-06DOI: 10.1016/j.mne.2025.100313
Jinyu Guo , Yifei Wang , Hao Quan , Shuoqiu Tian , Qiucheng Chen , Wentao Yuan , Qingxin Wu , Kangping Liu , Yifang Chen , Qiong He , Lei Zhou
Metasheets, composed of two identical metasurfaces closely aligned to each other within a mode-coupling distance on the two opposite sides of a SiNx membrane, are of unique functionalities for effective modulation of electromagnetic waves by nanoscale metallic structures. Although the physical image is readily clear, nanofabrication of such a two-sided devices with identical patterns still remains a big challenge because of the e-beam spreading caused by forward scattering in both resists and membranes. In this work, an innovative transmitted electron beam lithography (TEBL) was developed for metasheets. Three different resist stacks were tried and compared to eliminate the pattern deviation between them. A simulation study of TEBL was systematically carried out to figure out a reliable process window for replicating identical Au-gratings on the two opposite sides. The principle behind the success of replicating two identical metasurfaces on opposite sides is analyzed. The developed TEBL in this work extends the application of electron beam lithography to double-sided patterning for novel optical devices such as metasheets.
{"title":"Transmitted electron exposure in electron beam lithography for double-side patterning of bi-layer metasurfaces on a SiNx membrane","authors":"Jinyu Guo , Yifei Wang , Hao Quan , Shuoqiu Tian , Qiucheng Chen , Wentao Yuan , Qingxin Wu , Kangping Liu , Yifang Chen , Qiong He , Lei Zhou","doi":"10.1016/j.mne.2025.100313","DOIUrl":"10.1016/j.mne.2025.100313","url":null,"abstract":"<div><div>Metasheets, composed of two identical metasurfaces closely aligned to each other within a mode-coupling distance on the two opposite sides of a SiN<sub>x</sub> membrane, are of unique functionalities for effective modulation of electromagnetic waves by nanoscale metallic structures. Although the physical image is readily clear, nanofabrication of such a two-sided devices with identical patterns still remains a big challenge because of the e-beam spreading caused by forward scattering in both resists and membranes. In this work, an innovative transmitted electron beam lithography (TEBL) was developed for metasheets. Three different resist stacks were tried and compared to eliminate the pattern deviation between them. A simulation study of TEBL was systematically carried out to figure out a reliable process window for replicating identical Au-gratings on the two opposite sides. The principle behind the success of replicating two identical metasurfaces on opposite sides is analyzed. The developed TEBL in this work extends the application of electron beam lithography to double-sided patterning for novel optical devices such as metasheets.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100313"},"PeriodicalIF":3.1,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144830654","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}
Pub Date : 2025-08-05DOI: 10.1016/j.mne.2025.100310
P.F.J. van Altena , L. Castillo Ransanz , M. Manco , V.M. Heine , A. Accardo
Here, we report a high-resolution micro-digital light processing (μDLP) 3D printing protocol for fabricating soft hydrogel scaffolds featuring mesoscale millimetre-sized gyroid-based architectures tailored for 3D neural cell culture. The developed bioink formulation combines poly(ethylene glycol) diacrylate (PEGDA), as the structural backbone, and gelatin methacryloyl (GelMA), to enhance biocompatibility and promote cell adhesion via arginylglycylaspartic acid (RGD) motifs. By combining lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) as photoinitiator, along with tartrazine as photoabsorber, we achieved feature sizes down to 12.4 μm with high printing fidelity, reproducibility, and mechanical stability. The mechanical properties of the resulting hydrogel structures showed a Young's modulus (YM) in the 770 kPa – 2.25 MPa range, depending on the presence of GelMA, thus very relevant for neural cells (brain YM in the kPa range), along with remarkable biocompatibility (≈80 % cell viability) and good cell adhesion (≈55 % cell coverage). Two scaffold geometries based on triply periodic minimal surface gyroids were developed: a fully porous structure for culturing dissociated neuroepithelial stem cells and a hollow variant designed to host pre-formed neural organoids. Both scaffold types enabled strong cell adhesion and organoid sprouting, thereby demonstrating their suitability for advanced 3D culture systems. The results highlight the potential of μDLP-fabricated hydrogel meso-scale architectures as a platform for neuromechanobiology studies and tissue-mimetic engineering.
{"title":"Micro-digital light processing of conventional and hollow Gyroid mesoscale hydrogel scaffolds for neural cell cultures","authors":"P.F.J. van Altena , L. Castillo Ransanz , M. Manco , V.M. Heine , A. Accardo","doi":"10.1016/j.mne.2025.100310","DOIUrl":"10.1016/j.mne.2025.100310","url":null,"abstract":"<div><div>Here, we report a high-resolution micro-digital light processing (μDLP) 3D printing protocol for fabricating soft hydrogel scaffolds featuring mesoscale millimetre-sized gyroid-based architectures tailored for 3D neural cell culture. The developed bioink formulation combines poly(ethylene glycol) diacrylate (PEGDA), as the structural backbone, and gelatin methacryloyl (GelMA), to enhance biocompatibility and promote cell adhesion via arginylglycylaspartic acid (RGD) motifs. By combining lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) as photoinitiator, along with tartrazine as photoabsorber, we achieved feature sizes down to 12.4 μm with high printing fidelity, reproducibility, and mechanical stability. The mechanical properties of the resulting hydrogel structures showed a Young's modulus (YM) in the 770 kPa – 2.25 MPa range, depending on the presence of GelMA, thus very relevant for neural cells (brain YM in the kPa range), along with remarkable biocompatibility (≈80 % cell viability) and good cell adhesion (≈55 % cell coverage). Two scaffold geometries based on triply periodic minimal surface gyroids were developed: a fully porous structure for culturing dissociated neuroepithelial stem cells and a hollow variant designed to host pre-formed neural organoids. Both scaffold types enabled strong cell adhesion and organoid sprouting, thereby demonstrating their suitability for advanced 3D culture systems. The results highlight the potential of μDLP-fabricated hydrogel meso-scale architectures as a platform for neuromechanobiology studies and tissue-mimetic engineering.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100310"},"PeriodicalIF":3.1,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781788","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}
Pub Date : 2025-07-20DOI: 10.1016/j.mne.2025.100309
Robert Heinke , Lukáš Šilhan , Martin Ehrhardt , Pierre Lorenz , Joachim Zajadacz , Jens Bauer , Thomas Arnold , Mojmír Šerý , Klaus Zimmer
Masking of thin films and bulk materials is traditionally applied for the transfer of micron patterns into the functional material according to the requirements of the application. For optical purposes, lithographically produced micron patterns are transferred by plasma/ion etching, which is a traditional technology in microelectronics and other micron technologies. However, pattern transfer by atmospheric pressure plasma etching can help to save time and cost for a future sustainable production. Therefore, the pattern transfer of lithographic resist masks into fused silica using atmospheric pressure reactive plasma jets (APPJ) was studied as a new approach of micropatterning.
First the etch rates of the potential masking materials, e.g. photoresists, as well as of fused silica as substrate are studied in dependence on the APPJ etching parameters, in particular on the gas composition (O2/CF4) and the dwell time of the APPJ tool's footprint. Typical etch rates of the masking materials are in the range of 140 to 370 nm·s−1 whereas the fused silica has a rate of 25 to 80 nm·s−1. The surface morphology of masking materials changes during etching and features additional nanoscale roughness and waviness. The surface roughness of the etched masking materials and the fused silica are 2 to 5 nm rms and 1.5 nm rms for etch depths of ∼3000 nm and ∼ 600 nm, respectively. Finally, the pattern transfer by APPJ of a diffraction grating with a period of 15 μm, depth of 230 nm and a roughness below 2 nm rms into fused silica was demonstrated.
{"title":"Stability of masking materials for pattern transfer of lithographic masks into fused silica by atmospheric pressure plasma jet etching","authors":"Robert Heinke , Lukáš Šilhan , Martin Ehrhardt , Pierre Lorenz , Joachim Zajadacz , Jens Bauer , Thomas Arnold , Mojmír Šerý , Klaus Zimmer","doi":"10.1016/j.mne.2025.100309","DOIUrl":"10.1016/j.mne.2025.100309","url":null,"abstract":"<div><div>Masking of thin films and bulk materials is traditionally applied for the transfer of micron patterns into the functional material according to the requirements of the application. For optical purposes, lithographically produced micron patterns are transferred by plasma/ion etching, which is a traditional technology in microelectronics and other micron technologies. However, pattern transfer by atmospheric pressure plasma etching can help to save time and cost for a future sustainable production. Therefore, the pattern transfer of lithographic resist masks into fused silica using atmospheric pressure reactive plasma jets (APPJ) was studied as a new approach of micropatterning.</div><div>First the etch rates of the potential masking materials, e.g. photoresists, as well as of fused silica as substrate are studied in dependence on the APPJ etching parameters, in particular on the gas composition (O<sub>2</sub>/CF<sub>4</sub>) and the dwell time of the APPJ tool's footprint. Typical etch rates of the masking materials are in the range of 140 to 370 nm·s<sup>−1</sup> whereas the fused silica has a rate of 25 to 80 nm·s<sup>−1</sup>. The surface morphology of masking materials changes during etching and features additional nanoscale roughness and waviness. The surface roughness of the etched masking materials and the fused silica are 2 to 5 nm rms and 1.5 nm rms for etch depths of ∼3000 nm and ∼ 600 nm, respectively. Finally, the pattern transfer by APPJ of a diffraction grating with a period of 15 μm, depth of 230 nm and a roughness below 2 nm rms into fused silica was demonstrated.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100309"},"PeriodicalIF":2.8,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144687296","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}
Pub Date : 2025-06-28DOI: 10.1016/j.mne.2025.100307
L. Wouters , J. Cho , S. Gim , J. Yang , A. Kanniainen , K. Lee , P. Lagrain , N. Peric , T. Hantschel
Recently, a new scanning probe microscopy (SPM) concept called reverse tip sample scanning probe microscopy (RTS SPM) was introduced. Here, a sample is mounted at the end of a cantilever beam and scans over a tip that is integrated into an array of hundreds of SPM tips, overcoming one of the major limitations of the SPM technique, namely, the time-consuming and experiment-interrupting manual tip exchange step. However, to fully exploit this novel approach, a chip with an array of densely packed, nanometer-sharp, and durable SPM tips is essential. Therefore, we have developed a fabrication process to integrate such an array of sharp, high aspect ratio, doped diamond tips – referred to as hedgehog full diamond tip (HFDT) – into so-called probe chips, facilitating high-resolution SPM measurements and enabling rapid and seamless sample movement from one tip to another within the RTS SPM framework. An array of pyramidally shaped, doped diamond tips is fabricated through consecutive molding and diamond deposition steps. A supporting membrane is formed by metal deposition and electroplating, followed by selective underetching of the silicon substrate to release the tip array membrane and enable probe chip assembly. Finally, a self-patterned dry etching step is employed to generate multiple nanoscopic sharp tips on top of the base diamond pyramids. In this work, we present our developed and optimized probe chip technology and demonstrate its high electrical conductivity, robustness under high tip load force, and excellent spatial resolution, rendering it highly suitable for diverse electrical SPM measurement modes.
{"title":"Nanofabrication of sharp conductive diamond tip probe chips and their application in reverse tip sample scanning probe microscopy","authors":"L. Wouters , J. Cho , S. Gim , J. Yang , A. Kanniainen , K. Lee , P. Lagrain , N. Peric , T. Hantschel","doi":"10.1016/j.mne.2025.100307","DOIUrl":"10.1016/j.mne.2025.100307","url":null,"abstract":"<div><div>Recently, a new scanning probe microscopy (SPM) concept called reverse tip sample scanning probe microscopy (RTS SPM) was introduced. Here, a sample is mounted at the end of a cantilever beam and scans over a tip that is integrated into an array of hundreds of SPM tips, overcoming one of the major limitations of the SPM technique, namely, the time-consuming and experiment-interrupting manual tip exchange step. However, to fully exploit this novel approach, a chip with an array of densely packed, nanometer-sharp, and durable SPM tips is essential. Therefore, we have developed a fabrication process to integrate such an array of sharp, high aspect ratio, doped diamond tips – referred to as hedgehog full diamond tip (HFDT) – into so-called probe chips, facilitating high-resolution SPM measurements and enabling rapid and seamless sample movement from one tip to another within the RTS SPM framework. An array of pyramidally shaped, doped diamond tips is fabricated through consecutive molding and diamond deposition steps. A supporting membrane is formed by metal deposition and electroplating, followed by selective underetching of the silicon substrate to release the tip array membrane and enable probe chip assembly. Finally, a self-patterned dry etching step is employed to generate multiple nanoscopic sharp tips on top of the base diamond pyramids. In this work, we present our developed and optimized probe chip technology and demonstrate its high electrical conductivity, robustness under high tip load force, and excellent spatial resolution, rendering it highly suitable for diverse electrical SPM measurement modes.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100307"},"PeriodicalIF":2.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144534496","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}
Pub Date : 2025-06-28DOI: 10.1016/j.mne.2025.100308
E. Scattolo , A. Cian , J. Llobet , X. Borrise Nogue , S. Mondal , M. Barozzi , A. Bagolini , M. Crivellari , F. Pérez-Murano , D. Giubertoni
Silicon nanofabrication plays a crucial role in the development of advanced electronic, photonic, and quantum devices. Focused ion beam (FIB) milling is widely used for direct patterning at the nanoscale, but it requires high ion fluences, leading to long processing times, material redeposition, and increased contamination. In this work, we demonstrate an alternative FIB-based approach that relies on gold ion implantation at significantly lower fluences, enabling selective silicon etching while minimizing these drawbacks.
Gold ions (Au+) were implanted into silicon substrates with a kinetic energy of 35 keV, followed by wet etching in tetramethylammonium hydroxide (TMAH). We identified the process window of Au fluences between 1 × 1015 and 1 × 1017 ions/cm2, with secondary ion mass spectrometry (SIMS) confirming an Au concentration threshold of 3.5 × 1020 atoms/cm3 necessary to sustain etching resistance, value predicted also by Monte Carlo simulations (TRIDYN). This approach enables the fabrication of suspended silicon nanowires with a minimum width of 36 nm, a thickness of 20 nm, and lengths up to 8 μm, achieving aspect ratios exceeding 400, as well as more complex suspended structures likes nets which can be targeted for applications in nanoelectromechanical systems (NEMS) reaching nanowire width over pitch down to 2 %.
The proposed method presents a promising alternative to conventional silicon patterning, significantly reducing processing complexity while enhancing nanostructure resolution. The results provide new insights into ion-implantation-assisted etching mechanisms and expand the possibilities for silicon nanostructure fabrication.
{"title":"Silicon selective etching by gold implantation: Feasibility and nanofabrication capabilities","authors":"E. Scattolo , A. Cian , J. Llobet , X. Borrise Nogue , S. Mondal , M. Barozzi , A. Bagolini , M. Crivellari , F. Pérez-Murano , D. Giubertoni","doi":"10.1016/j.mne.2025.100308","DOIUrl":"10.1016/j.mne.2025.100308","url":null,"abstract":"<div><div>Silicon nanofabrication plays a crucial role in the development of advanced electronic, photonic, and quantum devices. Focused ion beam (FIB) milling is widely used for direct patterning at the nanoscale, but it requires high ion fluences, leading to long processing times, material redeposition, and increased contamination. In this work, we demonstrate an alternative FIB-based approach that relies on gold ion implantation at significantly lower fluences, enabling selective silicon etching while minimizing these drawbacks.</div><div>Gold ions (Au<sup>+</sup>) were implanted into silicon substrates with a kinetic energy of 35 keV, followed by wet etching in tetramethylammonium hydroxide (TMAH). We identified the process window of Au fluences between 1 × 10<sup>15</sup> and 1 × 10<sup>17</sup> ions/cm<sup>2</sup>, with secondary ion mass spectrometry (SIMS) confirming an Au concentration threshold of 3.5 × 10<sup>20</sup> atoms/cm<sup>3</sup> necessary to sustain etching resistance, value predicted also by Monte Carlo simulations (TRIDYN). This approach enables the fabrication of suspended silicon nanowires with a minimum width of 36 nm, a thickness of 20 nm, and lengths up to 8 μm, achieving aspect ratios exceeding 400, as well as more complex suspended structures likes nets which can be targeted for applications in nanoelectromechanical systems (NEMS) reaching nanowire width over pitch down to 2 %.</div><div>The proposed method presents a promising alternative to conventional silicon patterning, significantly reducing processing complexity while enhancing nanostructure resolution. The results provide new insights into ion-implantation-assisted etching mechanisms and expand the possibilities for silicon nanostructure fabrication.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"28 ","pages":"Article 100308"},"PeriodicalIF":2.8,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549877","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}
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