• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.81-86
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• 2004

A new method to improve the wet etching characteristics is described. The anisotropic wet-etching of (100) Si with megasonic wave has been studied in KOH solution. Etching characteristics of p-type (100) 6 inch Si have been explored with and without megasonic irradiation. It has been observed that megasonic irradiation improves the characteristics of wet etching such as an etch uniformity and surface roughness. The etching uniformity on the whole wafer with and without megasonic irradiation were less than ${\pm}1\%$ and more than $20\%$, respectively. The initial root-mean-square roughness($R_{rms}$) of single crystal silicon is 0.23 nm. It has been reported that the roughnesses with magnetic stirring and ultrasonic agitation were 566 nm and 66 nm, respectively. Comparing with the results, etching with megasonic irradiation achieved the Rrms of 1.7 nm on the surface after the $37{\mu}m$ of etching depth. Wet etching of silicon with megasonic irradiation can maintain nearly the original surface roughness after etching process. The results have verified that the megasonic irradiation is an effective way to improve the etching characteristics such as etch uniformity and surface roughness.

• Journal of Sensor Science and Technology
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• v.8 no.4
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• pp.308-313
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• 1999

This paper will present an anisotropic etching in TMAH technique used in the fabrication of three-dimensional magnetic field vector sensor based on angled Hall plate structure. This sensor design relies on simultaneously detecting all magnetic field vector components using Hall plates that are imbedded into the silicon [111] sloped-surface of bulk micromachined cavity by the anisotropic etching of [100] silicon. The fabricated Hall elements has relatively improved sensitivity compare to convensional Hall elements for three-dimensional magnetic field sensing. The product sensitivity of 547V/AT at the supply current of 1.0mA was achived. The corresponding limit in the detection of magnrtic field is 0.07G that calculated by measured power spectral density(PSD) in magnetic sensor output.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.16-17
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• 2006

We researched by the characteristic of a anisotropic etching of Si wafer and the Si career concerning the flip chip solder bump. Connectors and Anisotropic Conductive Film (ACF) method was already applied to board-to-board interconnection. In place of them, we have focused on board to board interconnection with solder bump by Si carrier, which has been used as Flip chip bonding technology. A major advantage of this technology is that the Flexible Printed Circuit (FPC) is connected in the same solder reflow process with other surface mount devices. This technology can be applied to semiconductors and electronic devices for higher functionality, integration and reliability.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.31-35
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• 2011

For high efficiency of Si-cells, Si wafers were textured by the KOH and NaOH etching solution to decreas the reflectance at surfaces of the cells. The textured surfaces were shown various types such as isotropic and anisotropic depending on the etching solution. The reflectance at sample of an anisotropic form with pyramid type was lower than that of isotropic form. The surface with isotropic form of general tiny circles on the surface increased the efficiency, however, the reflectance of it was increased. The efficiency was increased on surface with low roughness.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.1
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• pp.31-38
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• 2002

In order to improve the 0.35 $mutextrm{m}$-via hole etching process the etching characteristic of the gas $C_2F_{6}$ has been analyzed. The samples were triple-layer films(TEOS/SOG/TEOS) on 8-inch wafers and the orthogonal array matrix technique was used for the process. The equipment for etching was the transformer coupled plasma (TCP) source which is a type of high density plasma(HDP). This experiment showed the etching rate for $C_2F_{6}$ was 0.8 $mutextrm{m}$/min-1.1 $mutextrm{m}$/min and the measured uniformity was under $pm$6.9% in the matrix window. The CD skew comparison between pre and post-etching was under 10% which is an outstanding results in the window of profile in anisotropic etching. There was no problem in C2F6 with the flow rate of 20sccm, but when 14sccm of $C_2F_{6}$ was supplied there was a recess problem on the inner wall of SOG film. Consequently the etching characteristic of $C_2F_{6}$ shows a fast etching rate and a very wide process window in HDP TCP.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2241-2242
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• 2008

Anisotropic TMAH etching is key processing step for the fabrication of pendulum structure. During the etching, convex corners are attacked, and a proper compensating structure design is required when fabricating pendulum structures with sharp convex corner. In this paper, we present four compensation structures for convex corner compensation with 30% wt TMAH-water solution at $89\pm1^{\circ}C$ temperature, and observe the etched convex corner by optical microscope. we compare the result of calculations and experiments about four convex corner compensation patterns.

• Korean Journal of Materials Research
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• v.2 no.5
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• pp.383-386
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• 1992

In deep anisotropic etching of (100)-oriented Si substrate, it could be observed that the non-uniformities existing near the etched-edge were caused by lattice defects and mechanical stress at the etching interface.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.77-81
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• 2020

Silicon wafer etching in micro electro mechanical systems (MEMS) fabrication is challenging to form 3-D structures. Well known Si-wet etch of silicon employs potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH) and sodium hydroxide (NaOH). However, the existing silicon wet etching process has a fatal disadvantage that etching of the back side of the wafer is hard to avoid. In this study, a wet etching bath for 150 mm wafers was designed to prevent back-side etching of silicon wafer, and we demonstrated the optimized process recipe to have anisotropic wet etching of silicon wafer without any damage on the backside. We also presented the design of wet bath for 300 mm wafer processing as a promising process development.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3_1spc
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• pp.544-550
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• 2013

A grooved surface with anisotropic wettability was fabricated on a silicon substrate using photolithography, reactive ion etching, and a KOH etching process. The contact angles (CAs) of water droplets were measured and compared with the theoretical values in the Cassie state and Wenzel state. The experimental results showed that the contact area between a water droplet and a solid surface was important to determine the wettability of the water. The specimens with native oxide layers presented CAs ranging from $71.6^{\circ}$ to $86.4^{\circ}$. The droplets on the specimens with a native oxide layer could be in the Cassie state because they had relatively smooth surfaces. However, the CAs of the specimens with thick oxide layers ranged from $33.4^{\circ}$ to $59.1^{\circ}$. This indicated that the surface roughness for a specimen with a relatively thick oxide layer was higher, and the water droplet was in the Wenzel state. From the CA measurement results, it was observed that the wetting on the grooved surface was anisotropic for all of the specimens.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.117-122
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• 2001

In this paper, we report on photoelectrochemical etching process of 6H-SiC semiconductor wafer. The etching was performed in two-step process; anodization of SiC surface to form a deep porous layer and thermal oxidation followed by an HF dip. Etch rate of about 615${\AA}$/min was obtained during the anodization using a dilute HF(1.4wt% in H$_2$O) electrolyte with the etching potential of 3.0V. The etching rate was increased with the bias voltage. It was also found out that the adition of appropriate portion of H$_2$O$_2$ into the HF solution improves the etching rate. The etching process resulted in a higherly anisotropic etching characteristics and showed to have a potential for the fabrication of SiC devices with a novel design.