(Invited) High-Speed Plasma Etching of SiC Wafer Toward Backside Thinning

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.

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High-Speed Slicing of SiC Ingot by High-Speed Multi Wire Saw

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.771 ◽

2014 ◽

Vol 778-780 ◽

pp. 771-775 ◽

Cited By ~ 4

Author(s):

Hiroto Maeda ◽

Ryuichi Takanabe ◽

Atsunori Takeda ◽

Syogo Matsuda ◽

Tomohisa Kato

Keyword(s):

Single Crystal ◽

High Speed ◽

Low Cost ◽

Scale Up ◽

Wire Saw ◽

High Efficient ◽

Diamond Wire Sawing ◽

Relationship Of ◽

Sic Wafer ◽

The Relationship

Development of high efficient and high accuracy slice processing technology is required for realizing the high quality and low cost large SiC wafer. Our target of high speed slicing is slicing a 6 inch SiC single crystal ingot in about 9 hours. This slicing speed is about 10 times higher than the loose abrasive slurry sawing and about 4 times higher than the current technology of diamond wire sawing. The slicing speed and the slicing accuracy are in the relationship of trade-off. Therefore, in this research, we have studied the high speed slicing technique of 3 inch and 4 inch SiC single crystal ingot aiming at reduction of sliced wafers SORI. Moreover, we have extracted subjects to scale-up for the high speed slicing of the 6 inch SiC single crystal ingot.

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Dry Etch Self-Aligned AlInAs/InGaAs Heterojunction Bipolar Transistors

MRS Proceedings ◽

10.1557/proc-240-285 ◽

1991 ◽

Vol 240 ◽

Author(s):

T. R. Fullowan ◽

S. J. Pearton ◽

R. F. Kopf ◽

F. Ren ◽

Y. K. Chen ◽

...

Keyword(s):

Plasma Etching ◽

Heterojunction Bipolar Transistors ◽

High Speed ◽

Large Scale ◽

Electron Cyclotron Resonance ◽

Layer Structure ◽

Digital Circuit ◽

Bipolar Transistors ◽

High Yield ◽

Dry Etch

ABSTRACTA dry etch fabrication technology for high-speed AlInAs/InGaAs Heterojunction Bipolar Transistors (HBT's) utilizing low-damage Electron Cyclotron Resonance (ECR) CH4/H2/Ar plasma etching is detailed. The dry etch process uses triple self-alignment of the emitter and base metals and the base mesa, minimizing the base-collector capacitance (CBC). Devices with 2 × 4 μm2 emitters demonstrated current gains of 30–50 with ft and fmax values of ≥ 80 GHz and ≥100 GHz respectively. The structure employs a two-stage collector to achieve breakdown voltage (Vceo ) of 7V. The combination of processing and layer structure delivers truly scalable high yield AlInAs/InGaAs HBT's with both DC and RF characteristics suitable for large-scale, high speed digital circuit applications.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.740-742.813 ◽

2013 ◽

Vol 740-742 ◽

pp. 813-816 ◽

Cited By ~ 1

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.

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Thinning of SiC Wafer by Plasma Chemical Vaporization Machining

Materials Science Forum ◽

10.4028/www.scientific.net/msf.645-648.857 ◽

2010 ◽

Vol 645-648 ◽

pp. 857-860 ◽

Cited By ~ 5

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.

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Back-Side Thinning of Silicon Carbide Wafer by Plasma Etching Using Atmospheric-Pressure Plasma

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.516.108 ◽

2012 ◽

Vol 516 ◽

pp. 108-112 ◽

Cited By ~ 1

Author(s):

Yasuhisa Sano ◽

Kohei Aida ◽

Hiroaki Nishikawa ◽

Kazuya Yamamura ◽

Satoshi Matsuyama ◽

...

Keyword(s):

Silicon Carbide ◽

Plasma Etching ◽

Atmospheric Pressure ◽

Removal Rate ◽

Thickness Distribution ◽

Atmospheric Pressure Plasma ◽

Back Side ◽

Wafer Level ◽

Pressure Plasma ◽

Sic Wafer

Silicon carbide (SiC) power devices have received much attention in recent years because they enable the fabrication of devices with low power consumption. To reduce the on-resistance in vertical power transistors, back-side 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 SiC wafer by plasma chemical vaporization machining (PCVM), which is plasma etching using atmospheric-pressure plasma. The wafer level thinning of a 2-inch 4H-SiC wafer has been possible without a removal thickness distribution caused by the circular shape of the wafer using the newly developed PCVM apparatus for back-side thinning with a spatial wafer stage.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.717-720.865 ◽

2012 ◽

Vol 717-720 ◽

pp. 865-868 ◽

Cited By ~ 3

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.

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