Research on Sapphire Deep Cavity Corrosion and Mask Selection Technology

Aimed at the problem of the small wet etching depth in sapphire microstructure processing technology, a multilayer composite mask layer is proposed. The thickness of the mask layer is studied, combined with the corrosion rate of different materials on sapphire in the sapphire etching solution, different mask layers are selected for the corrosion test on the sapphire sheet, and then the corrosion experiment is carried out. The results show that at 250 °C, the choice is relatively high when PECVD (Plasma Enhanced Chemical Vapor Deposition) is used to make a double-layer composite film of silicon dioxide and silicon nitride. When the temperature rises to 300 °C, the selection ratio of the silicon dioxide layer grown by PECVD is much greater than that of the silicon nitride layer. Therefore, under high temperature conditions, a certain thickness of silicon dioxide can be used as a mask layer for deep cavity corrosion.

The Urban Mask Layer as Reference Geometry for Spatial Planning: Moving from German to European Geodata

In view of rising urbanisation around the world, it is vital to improve the analysis and evaluation of spatial settlement structures in order to ensure the sustainable design of associated transformation processes. Geodata and the maps derived from urban datasets can contribute significantly to understanding the characteristics of settlement structures. In this context, urban areas with a concentration of settlement elements form an important reference geometry. In Germany, such an urban mask is termed Ortslage and is included as an object type in the official topographical basic geodata (ATKIS). It would be useful to have a similar urban mask at European level, especially as a layer of the Urban Atlas within the framework of the Copernicus Land Monitoring Service. Here we present a GIS-supported algorithm to generate such a layer from Urban Atlas data. The method is demonstrated on 30 European cities showing a wide range of urban structures. Further, we compare the physical shape of the Ortslage with the urban mask, here illustrated by the city of Leipzig, Germany. As a basic example of the planning relevance of this method, we consider and discuss the metric shape complexity of the urban space for the cartographic comparison of cities. Furthermore, we address the question of a mixed automated-manual technology in the delineation of the urban mask. The regular updating of the Urban Atlas data within the framework of the Copernicus Land Monitoring Service opens up the possibility of integrating analyses based on the urban masks into the European Spatial Observation.

Monaural Singing Voice and Accompaniment Separation Based on Gated Nested U-Net Architecture

This paper proposes a separation model adopting gated nested U-Net (GNU-Net) architecture, which is essentially a deeply supervised symmetric encoder–decoder network that can generate full-resolution feature maps. Through a series of nested skip pathways, it can reduce the semantic gap between the feature maps of encoder and decoder subnetworks. In the GNU-Net architecture, only the backbone not including nested part is applied with gated linear units (GLUs) instead of conventional convolutional networks. The outputs of GNU-Net are further fed into a time-frequency (T-F) mask layer to generate two masks of singing voice and accompaniment. Then, those two estimated masks along with the magnitude and phase spectra of mixture can be transformed into time-domain signals. We explored two types of T-F mask layer, discriminative training network and difference mask layer. The experiment results show the latter to be better. We evaluated our proposed model by comparing with three models, and also with ideal T-F masks. The results demonstrate that our proposed model outperforms compared models, and it’s performance comes near to ideal ratio mask (IRM). More importantly, our proposed model can output separated singing voice and accompaniment simultaneously, while the three compared models can only separate one source with trained model.

Functional nano-structuring of thin silicon nitride membranes

The paper describes the development and production of a nano-optical device consisting of a nano-perforated layer of silicon nitride stretched in a single-crystal silicon frame using electron beam lithography (EBL) and reactive ion etching (RIE) techniques. Procedures for transferring nanostructures to the nitride layer are described, starting with the preparation of a metallic mask layer by physical vapor deposition (PVD), high-resolution pattern recording technique using EBL and the transfer of the motif into the functional layer using the RIE technique. Theoretical aspects are summarized including technological issues, achieved results and application potential of patterned silicon nitride membranes.

Process Parameter Control for BEOL TiN Hard Mask Etch-Back

In this paper we demonstrate an effective process control mechanism to significantly improve on the process performance of a BEOL post-etch cleaning process with an integrated partial or complete removal of the TiN HM (hard mask) layer by so called formulated chemistries on a single wafer processing tool. The novel process control mechanism enables a 50% reduction in chemical consumption while achieving an at least equivalent TiN etch uniformity.

Surface Modification of Block Copolymer Through Sulfur Containing Plasma Treatment

Some of the important issues of block copolymer (BCP) as an application to the potential low cost next generation lithography are thermal stability and deformation during pattern transfer process in addition to defect density, line edge/width roughness, etc. In this study, sulfur containing plasma treatment was used to modify the BCP and the effects of the plasma on the properties of plasma treated BCP were investigated. The polystyrene hole pattern obtained from polystyrene polystyreneblock-poly(methylmethacrylate) (PS-b-PMMA) was initially degraded when the polystyrene hole was annealed at 190°C for 15 min. However, when the hole pattern was treated using sulfur containing plasmas using H2S or SF6 up to 2 min, possibly due to the sulfurization of the polystyrene hole surface, no change in the hole pattern was observed after the annealing even though there is a slight change in hole shapes during the plasma treatment. The optimized plasma treated polystyrene pattern showed the superior characteristics as the mask layer by showing better thermal stability, higher chemical inertness, and higher etch selectivity during plasma etching.

Low Cost Ion Implantation Process with High Heat Resistant Photoresist in Silicon Carbide Device Fabrication

Cost of silicon carbide (SiC) wafer has been improved owing to the development of larger and higher quality wafer technologies, while the process stays long and complicated. In this paper, we propose a novel short process of ion implantation and provide the fabrication model SiC schottky barrier diodes (SiC-SBDs) devices. Currently common mask layer of ion implantation employs high heat resistant materials such as metal oxides. Because the ion is implanted to SiC wafer at high temperature between 300 °C and 800 °C due to avoid the damage of SiC crystal structure. The process using oxide layer tends to became long and complicated. On the other hand, our proposal process uses a heat resistant photoresist material as the mask instead of the oxide layer. The heat resistant photoresist is applied to newly developed SP-D1000 produced by Toray Industries, Inc.. We demonstrated to fabricate model SiC-SBDs devices based on our proposal process with SP-D1000 and confirmed the device working as same as a current process.

A Novel Method to Fabricate Silicon-Beam with Polygon Section Based on Thermal Oxidation Layer Protection Technique

Simplex wet etching method to fabricate silicon-beam has limited the categories of silicon-beam, it has confined the design and fabrication of silicon-beam with polygon section. Moreover, due to the side-etching of sidewalls and arris during the process of wet etching, the sections of the fabricated silicon-beam are not identical, which will induce the mechanics characters of silicon-beam to be altered, depressing the quality of silicon-beam; In order to avoid the shortages above, a novel method to fabricate silicon-beam with polygon section based on thermal oxidation layer technique is proposed, thermal oxidation SiO2 layer is utilized as the protection layer of the sidewalls of the silicon-beam instead of the mask layer as usual for the first time. Combining the wet etching technique with the thermal oxidation technique innovatively, several varieties of silicon-beam with polygon section, which can hardly be obtained only by the use of wet etching technique, can be manufactured, respectively. Based on such an innovative method, this paper proposes and develops five varieties of silicon-beam with novel structure by means of adjustable mask layer, extending the application field of wet etching. The subsequent fabrication experiment of silicon-beam with hexagonal section has been taken as an example to validate the technique principle. The dimension parameters of silicon-beam have been tested precisely and the arris angle error between the theoretic value and the experimental measurement is less than 1.5%; The SEM photos with the amplifier of 100 and 250 have been obtained through HITACHI S-4800 field emission scanning electron microscope (FE-SEM), the SEM results have demonstrated the clear sidewall arris without undercut. Through this fabrication method, the sidewall arris of silicon-beam can be maintained due to the protection layer of thermal oxidation SiO2. In this manner, the arris disfigurement of the silicon-beam decreases dramatically, the process of etching can be controlled precisely, and the quality of the silicon-beam has been improved greatly.