Polishing Characteristics of 4H-SiC Si-Face and C-Face by Plasma Chemical Vaporization Machining

2007 ◽  
Vol 556-557 ◽  
pp. 757-760
Author(s):  
Yasuhisa Sano ◽  
Masayo Watanabe ◽  
Kazuya Yamamura ◽  
Kazuto Yamauchi ◽  
Takeshi Ishida ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Etch Rate ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
Plasma Chemical ◽  
Machined Surface ◽  
Pressure Plasma ◽  
High Etch Rate ◽  
High Removal Rate ◽  
Conventional Machining

Silicon carbide (SiC) is a promising semiconductor material for power devices. However, it is so hard and so chemically stable that there is no efficient method of machining it without causing damage to the machined surface. Plasma chemical vaporization machining (PCVM) is plasma etching in atmospheric-pressure plasma. PCVM has a high removal rate equivalent to those of conventional machining methods such as grinding and lapping, because the radical density in atmospheric-pressure plasma is much higher than that in normal low-pressure plasma. In this paper, the polishing characteristics of SiC by PCVM are described. As a result of machining, the surface roughnesses of both Si- and C-faces were improved under a relatively low-etch-rate (100-200 nm/min) condition. The C-face was also improved under a relatively high-etch-rate (approximately 10 μm/min) condition, and a very smooth surface (below 2 nm peak-to-valley in a 500-nm-square area) was achieved.

Temperature Dependence of Plasma Chemical Vaporization Machining of Silicon and Silicon Carbide

2008 ◽  
Vol 600-603 ◽  
pp. 847-850 ◽  
Author(s):  
Yasuhisa Sano ◽  
Masayo Watanabe ◽  
Takehiro Kato ◽  
Kazuya Yamamura ◽  
Hidekazu Mimura ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Temperature Dependence ◽  
Atmospheric Pressure ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
Plasma Chemical ◽  
Machined Surface ◽  
Pressure Plasma ◽  
Temperature Dependences ◽  
High Removal Rate

Silicon carbide (SiC) is a promising semiconductor material for power devices. However, it is extremely hard and chemically stable; thus there is no efficient method of machining it without causing damage to the machined surface. Plasma chemical vaporization machining (PCVM) is plasma etching in atmospheric-pressure plasma. PCVM has a high removal rate because the radical density in atmospheric-pressure plasma is much higher than that in conventional low-pressure plasma. Although it was found that the machining characteristic of SiC by PCVM had stronger rf power dependence than that of Si, it has not been clear whether it is radical density dependence or temperature dependence. In this paper, the temperature dependences of the PCVM of Si and SiC are examined using pipe electrode apparatus. As a result, it is found that the removal rate of SiC has a much stronger temperature dependence than that of Si and that the surface roughness of the SiC Si face becomes worse as the etching temperature increases whereas that of the C face does not increase at etching temperatures of up to 360°C.

Beveling of Silicon Carbide Wafer by Plasma Chemical Vaporization Machining

2008 ◽  
Vol 600-603 ◽  
pp. 843-846 ◽  
Author(s):  
Takehiro Kato ◽  
Yasuhisa Sano ◽  
Hideyuki Hara ◽  
Hidekazu Mimura ◽  
Kazuya Yamamura ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Atmospheric Pressure ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
High Hardness ◽  
Wafer Surface ◽  
Plasma Chemical ◽  
Pressure Plasma ◽  
Surface Polishing ◽  
High Removal Rate

Beveling is essential for preventing the chipping of the edge of a wafer during surface polishing and other processes. Plasma chemical vaporization machining (PCVM) is an atmospheric-pressure plasma etching process. It has a high removal rate equivalent to those of conventional machining methods such as grinding and lapping, which are used for high-hardness materials such as silicon carbide, due to the generation of high-density radicals in atmospheric-pressure plasma. Furthermore, PCVM does not damage the wafer surface because it is a purely chemical process; therefore, it is considered that PCVM can be used as an effective method of beveling the edge of SiC wafers. In this paper, we report the investigation of the beveling of SiC wafers by PCVM.

Dicing of SiC Wafer by Atmospheric-Pressure Plasma Etching Process with Slit Mask for Plasma Confinement

2014 ◽  
Vol 778-780 ◽  
pp. 759-762 ◽  
Author(s):  
Yasuhisa Sano ◽  
Hiroaki Nishikawa ◽  
Yuu Okada ◽  
Kazuya Yamamura ◽  
Satoshi Matsuyama ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Atmospheric Pressure ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
Etching Process ◽  
Plasma Confinement ◽  
Plasma Etching Process ◽  
Pressure Plasma ◽  
High Removal Rate ◽  
Sic Wafer

Silicon carbide (SiC) is a promising semiconductor material for high-temperature, high-frequency, high-power, and energy-saving applications. However, because of the hardness and chemical stability of SiC, few conventional machining methods can handle this material efficiently. A plasma chemical vaporization machining (PCVM) technique is an atmospheric-pressure plasma etching process. We previously proposed a novel style of PCVM dicing using slit apertures for plasma confinement, which in principle can achieve both a high removal rate and small kerf loss, and demonstration experiments were performed using a silicon wafer as a sample. In this research, some basic experiments were performed using 4H-SiC wafer as a sample, and a maximum removal rate of approximately 10 μm/min and a narrowest groove width of 25 μm were achieved. We also found that argon can be used for plasma generation instead of expensive helium gas.

Cutting of SiC Wafer by Atmospheric-Pressure Plasma Etching with Wire Electrode

2012 ◽  
Vol 717-720 ◽  
pp. 865-868 ◽  
Author(s):  
Yasuhisa Sano ◽  
Kohei Aida ◽  
Takehiro Kato ◽  
Kazuya Yamamura ◽  
Hidekazu Mimura ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Atmospheric Pressure ◽  
Etch Rate ◽  
Atmospheric Pressure Plasma ◽  
Wire Electrode ◽  
Rf Power ◽  
Pressure Plasma ◽  
Power And Energy ◽  
Sic Wafer ◽  
Conventional Machining

Silicon carbide (SiC) is a promising semiconductor material for high-temperature, high-frequency, high-power, and energy-saving applications. However, it is so hard and chemically stable that there are few efficient conventional machining methods for it. We have developed plasma chemical vaporization machining (PCVM), an atmospheric-pressure plasma etching process, and investigated its application to the processing of SiC substrates. In this paper, the cutting characteristics of a SiC substrate by PCVM with a wire electrode are described. We found that increasing the rf power and reactive gas concentration increases the etch rate and that the etch width can be reduces by increasing the SF6 concentration. The maximum etch rate was 2.1 μm/min and the minimum etch width was 220 μm. It was also demonstrated that a SiC wafer prethinned to 100 μm can be successfully cut without breaking or cracking.

scholarly journals Development of computer-controlled atmospheric pressure plasma structuring for 2D/3D pattern on fused silica

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duo Li ◽  
Peng Ji ◽  
Yang Xu ◽  
Bo Wang ◽  
Zheng Qiao ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Mechanical Load ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
Fused Silica ◽  
Phase Plate ◽  
Gaussian Shape ◽  
Lens Array ◽  
Pressure Plasma ◽  
Computer Controlled

AbstractFused silica with structured and continuous patterns is increasingly demanded in advanced imaging and illumination fields because of its excellent properties and functional performance. Atmospheric pressure plasma, based on pure chemical etching under atmospheric pressure, is developed as a promising fabrication technique for fused silica due to its deterministic high material removal rate, controllable removal imprint and no mechanical load. The stable and controllable Gaussian-shape removal function makes computer-controlled plasma tool potential to generate complex structures with high accuracy, efficiency and flexibility. In the paper, computer-controlled atmospheric pressure plasma structuring (APPS) is proposed to fabricate 2D/3D patterns on fused silica optics. The capacitively coupled APPS system with a double-layer plasma torch and its discharge characteristics are firstly developed. By means of multi-physics simulation and process investigation, the stable and controllable Gaussian-shape removal function can be achieved. Two different structuring modes, including discrete and continuous APPS, are explored for 2D/3D patterns. A series of structuring experiments show that different kinds of 2D patterns (including square lens array, hexagon lens array and groove array) as well as complex 3D phase plate patterns have been successfully fabricated, which validates the effectiveness of the proposed APPS of 2D/3D patterns on fused silica optics.

Thinning of a Two-Inch Silicon Carbide Wafer by Plasma Chemical Vaporization Machining Using a Slit Electrode

2014 ◽  
Vol 778-780 ◽  
pp. 750-753 ◽  
Author(s):  
Yuu Okada ◽  
Hiroaki Nishikawa ◽  
Yasuhisa Sano ◽  
Kazuya Yamamura ◽  
Kazuto Yamauchi
Keyword(s):  
Silicon Carbide ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
High Hardness ◽  
Power Devices ◽  
Plasma Chemical ◽  
Power Transistors ◽  
Device Processing ◽  
High Removal Rate ◽  
Sic Wafer

In recent years, silicon (Si) has been mainly used in power devices, but the limit of its performance is being reached. Therefore, silicon carbide (SiC) power devices have been attracting attention because they enable the fabrication of devices with 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 processing because its high hardness and brittleness cause cracking and chipping during thinning. Therefore, we have attempted to thin a SiC wafer using plasma chemical vaporization machining (PCVM), which is plasma etching using atmospheric-pressure plasma. In this study, we describe a machining property using a newly developed slit electrode that is composed of two parts and has a slit that allows for a new gas to pass.

Basic Experiment on Atmospheric-Pressure Plasma Etching with Slit Aperture for High-Efficiency Dicing of SiC Wafer

2013 ◽  
Vol 740-742 ◽  
pp. 813-816 ◽  
Author(s):  
Yasuhisa Sano ◽  
Hiroaki Nishikawa ◽  
Kohei Aida ◽  
Chaiyapat Tangpatjaroen ◽  
Kazuya Yamamura ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Atmospheric Pressure ◽  
High Efficiency ◽  
Atmospheric Pressure Plasma ◽  
Slit Width ◽  
Etching Depth ◽  
Pressure Plasma ◽  
Power And Energy ◽  
Sic Wafer ◽  
Conventional Machining

Silicon carbide (SiC) is a promising semiconductor material for high-temperature, high-frequency, high-power, and energy-saving applications. However, because the hardness and chemical stability of SiC are high, few conventional machining methods can handle this material efficiently. We previously developed a plasma chemical vaporization machining (PCVM) technique, which is an atmospheric-pressure plasma etching process, and investigated its application to the processing of SiC substrates. In this paper, we propose a novel style of PCVM technique for dicing, using slit apertures to confine the plasma. From experiments by means of an apparatus with a one-slit aperture formed by two masks, it was found that the kerf loss was almost proportional to the slit width, and that the etching depth increased with RF power. Furthermore, from experiments on a SiC wafer, we obtained a 130-μm etching depth and 300-μm kerf loss for an 11-min processing time and 200-μm slit width.

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.

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