Basic Study on Etching Selectivity of Plasma Chemical Vaporization Machining by Introducing Crystallographic Damage into Work Surface

2014 ◽  
Vol 625 ◽  
pp. 550-553 ◽  
Author(s):  
Yasuhisa Sano ◽  
Toshiro Doi ◽  
Syuhei Kurokawa ◽  
Hideo Aida ◽  
Osamu Ohnishi ◽  
...  
Keyword(s):  
High Speed ◽  
Substrate Surface ◽  
Etching Rate ◽  
Atmospheric Pressure Plasma ◽  
Mean Free Path ◽  
Machining Process ◽  
Plasma Chemical ◽  
Basic Study ◽  
Cross Sectional ◽  
Mechanical Machining

Plasma chemical vaporization machining (PCVM) is a high-speed plasma etching method using atmospheric-pressure plasma. Although it does not leave an affected layer on the processed surface because of the small ion energy owing to the small mean free path of gas molecules, it is not suitable for planarization because of its isotropic etching. Thus, a combination of PCVM and a mechanical machining process is proposed. The convex parts of a substrate surface are considered to be affected by mechanical machining and are removed preferentially by PCVM. In this report, it is investigated whether etching rate of the affected layer becomes larger or not. As a result, it was found that the etching rate increased in the first 100 nm depth of the mechanically polished substrate, which corresponds to the thickness of the heavily damaged layer observed by cross-sectional transmission electron microscopy.

Next-Generation, Super-Hard-to-Process Substrates and Their High-Efficiency Machining Process Technologies Used to Create Innovative Devices

2018 ◽  
Vol 12 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Toshiro Doi ◽  
Keyword(s):  
Chemical Mechanical Polishing ◽  
High Speed ◽  
High Efficiency ◽  
High Pressure Processing ◽  
Machining Process ◽  
Next Generation ◽  
Plasma Chemical ◽  
Plasma Fusion ◽  
Ultra Precision ◽  
Efficient Processing

SiC, GaN, and diamond are known as super-hard-to-process substrate for next-generation green devices. In this paper, we report on some breakthrough in developing highly efficient processing for such hard-to-process materials, for which we propose improvements in conventional processing, and innovative processing. As part of our project, we developed a “dilatancy pad®” that can efficiently produce high-quality surfaces as well as a high-rigidity, high-speed and high-pressure processing machine. We also designed and prototyped “plasma fusion CMP®,” which is an innovative processing technology fusing CMP (Chemical Mechanical Polishing) with P-CVM (Plasma Chemical Vaporization Machining) to machine super-hard diamond substrates that are considered indispensable for future devices. Before the advent of “singularities” by 2045, super-hard-to-process substrates and ultra-precision polishing technology will become more and more essential.

Burr Formation and Surface Quality in High Speed Micromilling of Titanium Alloy (Ti6Al4V)

2013 ◽  
Author(s):  
Vivek Bajpai ◽  
Ajay K. Kushwaha ◽  
Ramesh K. Singh
Keyword(s):  
High Speed ◽  
Removal Rate ◽  
Weight Ratio ◽  
Machining Process ◽  
Burr Formation ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Good Surface ◽  
Mechanical Machining ◽  
Tool Diameter

Titanium and Ti alloys are popular materials used in aviation and biomedical field due to their excellent strength-to-weight ratio and corrosion resistance properties. Micromilling is a common mechanical machining process used in the production of microscale features. The micro-tool has very low stiffness and even small forces can lead to catastrophic tool failure. High speed micromachining can be used to address the issue because of lower chip loads at higher rotational speeds. Consequently, high speed micromilling can be used for micromachining of hard metals/alloys which are difficult to accomplish at lower speeds. Nowadays high speed micromilling is gaining popularity due to its high material removal rate and good surface finish. In many cases, the machined product does not need an additional finishing process. However, the burr formation in the mechanical machining process is the most important problem which becomes more critical for a microscale feature. Removal of micro-size burr is much more difficult than its macro counterpart. The current work is focused on the characterization of the burr formation in high speed micromilling. Influence of various process parameters, viz., spindle speed, feed rate, depth of cut, tool diameter and number of flutes of the micromilling tool has been analyzed on the burr size and on the quality of the machined surface via measuring the surface roughness.

Plasma Chemical Vaporization Machining of Silicon Carbide Wafer Using Flat-Bar Electrode with Multiple Gas Nozzles

2012 ◽  
Vol 497 ◽  
pp. 160-164 ◽  
Author(s):  
Yasuhisa Sano ◽  
Kohei Aida ◽  
Hiroaki Nishikawa ◽  
Kazuya Yamamura ◽  
Satoshi Matsuyama ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
High Hardness ◽  
Plasma Chemical ◽  
Power Transistors ◽  
Device Processing ◽  
High Removal Rate ◽  
Mechanical Machining ◽  
Sic Wafer

Silicon carbide (SiC) power devices have received much attention in recent years because they enable the fabrication of devices with a low power consumption. To reduce the on-resistance in vertical power transistors, backside thinning is required after device processing. However, it is difficult to thin a SiC wafer with a high removal rate by conventional mechanical machining because its high hardness and brittleness cause cracking and chipping during thinning. We have attempted to thin a SiC wafer by plasma chemical vaporization machining (PCVM), which is plasma etching using atmospheric-pressure plasma. In this paper, we describe a machining property using a newly developed flat-bar electrode with multiple gas nozzles for thinning a SiC wafer.

Thinning of SiC Wafer by Plasma Chemical Vaporization Machining

2010 ◽  
Vol 645-648 ◽  
pp. 857-860 ◽  
Author(s):  
Yasuhisa Sano ◽  
Takehiro Kato ◽  
Tsutomu Hori ◽  
Kazuya Yamamura ◽  
Hidekazu Mimura ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
High Hardness ◽  
High Yield ◽  
Plasma Chemical ◽  
Power Transistors ◽  
Device Processing ◽  
Mechanical Machining ◽  
Sic Wafer

In order to reduce the on-resistance in vertical power transistors, backside thinning is required after device processing. However, it is difficult to thin an SiC wafer with a high yield rate by conventional mechanical machining because its high hardness and brittleness cause cracking and chipping during thinning. In this study, a small rectangular SiC sample was thinned by plasma chemical vaporization machining (PCVM), which is plasma etching using atmospheric-pressure plasma. As a result, the sample was successfully thinned to 40 m without any cracking or chipping. Furthermore, the surface roughness was improved after thinning, and the edge of the wafer became rounded automatically. Therefore, PCVM can be used as an effective method for thinning SiC wafers.

scholarly journals XXV Международный симпозиум Нанофизика и наноэлектроника", Нижний Новгород, 9-12 марта 2021 г. Влияние добавки хлорпентафторэтана в составе хлорсодержащей плазмы на скорость и характеристики профиля травления арсенида галлия

2021 ◽  
Vol 55 (10) ◽  
pp. 837
Author(s):  
А.И. Охапкин ◽  
С.А. Краев ◽  
Е.А. Архипова ◽  
В.М. Данильцев ◽  
О.И. Хрыкин ◽  
...  
Keyword(s):  
Gallium Arsenide ◽  
Inductively Coupled Plasma ◽  
Substrate Surface ◽  
Etching Rate ◽  
Plasma Chemical ◽  
Inductively Coupled ◽  
Initial Stage ◽  
Plasma Chemical Etching ◽  
Etching Profile ◽  
By Products

In this work, the dependence of plasma-chemical etching rate and the roughness of the surface of gallium arsenide crater on chloropentafluoroethane (C2F5Cl) concentration in a mixture with chlorine, forward power and etching duration were studied. Characteristics of GaAs etching crater were studied by white light interferometry and scanning electron microscopy. It is shown that C2F5Cl addition in chlorine-containing inductively coupled plasma led to a nonlinear change of gallium arsenide etching rate with time which can be explained by passivation of substrate surface at the initial stage by products of freon decay. Along with this, characteristics of the etching profile of GaAs are significantly improved. Forward power increase contributes to development of roughness, while the etching rate increases nonlinearly.

Growth and Characterization of UHV/CVD Si/SiGe Strained-Layer Superlattices on Bulk Crystal SiGe Substrates

2001 ◽  
Vol 686 ◽  
Author(s):  
S.R. Sheng ◽  
M. Dion ◽  
S.P. Mcalister ◽  
N.L. Rowell
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Near Band Edge ◽  
Bulk Single Crystal ◽  
Cross Sectional ◽  
Strained Layer ◽  
Short Period ◽  
Strained Layer Superlattices

AbstractHigh-quality short-period Si/SiGe strained-layer superlattices have been grown on bulk single-crystal SiGe substrates using a commercial low-temperature ultrahigh vacuum chemical vapor deposition (UHV/CVD) reactor. These superlattices were characterized by high-resolution x-ray diffraction (HRXRD), Auger electron spectroscopy (AES), atomic force microscopy (AFM), cross-sectional transmission electron microscopy (XTEM) and photoluminescence (PL). HRXRD, AES, and XTEM results confirm that the materials deposited are high crystal-quality superlattice layers with abrupt interfaces and excellent thickness and composition uniformity across superlattices of 5 periods. AFM images show similar surface RMS roughness of much less than 1 nm for both the top layer surface and the starting substrate surface, indicating very smooth surfaces. PL measurements further confirm material quality and composition, and show sharp, well-resolved near band-edge BE and FE PL and strong broad sub-gap PL perhaps related to direct-gap superlattice transitions. The materials grown here are very promising for applications of both high-speed electronic devices and high-efficiency optoelectronic devices.

Thinning of 2-Inch SiC Wafer by Plasma Chemical Vaporization Machining Using Cylindrical Rotary Electrode

2011 ◽  
Vol 679-680 ◽  
pp. 481-484 ◽  
Author(s):  
Yasuhisa Sano ◽  
Takehiro Kato ◽  
Kohei Aida ◽  
Kazuya Yamamura ◽  
Hidekazu Mimura ◽  
...  
Keyword(s):  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
High Hardness ◽  
Scanning Speed ◽  
Plasma Chemical ◽  
Power Transistors ◽  
Device Processing ◽  
High Removal Rate ◽  
Mechanical Machining ◽  
Sic Wafer

To reduce the on-resistance in vertical power transistors, backside thinning is required after device processing. However, it is difficult to thin a SiC wafer with a high removal rate by conventional mechanical machining because its high hardness and brittleness cause cracking and chipping during thinning. In this study, we attempted to thin a 2-inch 4H-SiC wafer by plasma chemical vaporization machining (PCVM), which is plasma etching using atmospheric-pressure plasma. By controlling the scanning speed of the table and optimizing the oxygen percentage in the CF4+O2+He mixture gas, a maximum removal rate of 0.56 μm/min was obtained over the entire wafer. Furthermore, the surface roughness was improved after thinning. Therefore, PCVM can be used as an effective method for thinning SiC wafers.

TEM characterization of silicon epitaxial layer grown on Si-TaS2, eutectic composites

1991 ◽  
Vol 49 ◽  
pp. 802-803
Author(s):  
C.M. Sung ◽  
M. Levinson ◽  
M. Tabasky ◽  
K. Ostreicher ◽  
B.M. Ditchek
Keyword(s):  
Substrate Surface ◽  
Bulk Sample ◽  
Surface Cleaning ◽  
Native Oxide ◽  
Czochralski Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Cleaning Methods ◽  
Field Emission Cathodes

Directionally solidified Si/TaSi2 eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2 substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2 composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2 fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+ until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.

Ion thinning of integrated circuit transverse specimens for transmission electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1426-1427
Author(s):  
F. Shaapur
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuit ◽  
Substrate Surface ◽  
Homogeneous Material ◽  
Material System ◽  
Ion Milling ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Motion Profile

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.

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