Dry Etching of Germanium with Laser Induced Reactive Micro Plasma

AbstractHigh-quality, ultra-precise processing of surfaces is of high importance for high-tech industry and requires a good depth control of processing, a low roughness of the machined surface and as little as possible surface and subsurface damage but cannot be realized by laser ablation processes. Contrary, electron/ion beam, plasma processes and dry etching are utilized in microelectronics, optics and photonics. Here, we have demonstrated a laser-induced plasma (LIP) etching of single crystalline germanium by an optically pumped reactive plasma, resulting in high quality etching. A Ti:Sapphire laser (λ = 775 nm, EPulse/max. = 1 mJ, t = 150 fs, frep. = 1 kHz) has been used, after focusing with a 60 mm lens, for igniting a temporary plasma in a CF4/O2 gas at near atmospheric pressure. Typical etching rate of approximately ~ 100 nm / min and a surface roughness of less than 11 nm rms were found. The etching results were studied in dependence on laser pulse energy, etching time, and plasma – surface distance. The mechanism of the etching process is expected to be of chemical nature by the formation of volatile products from the chemical reaction of laser plasma activated species with the germanium surface. This proposed laser etching process can provide new processing capabilities of materials for ultra—high precision laser machining of semiconducting materials as can applied for infrared optics machining.

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Dry Etching of GaN Using Reactive Ion Beam Etching and Chemically Assisted Reactive Ion Beam Etching

MRS Proceedings ◽

10.1557/proc-468-373 ◽

1997 ◽

Vol 468 ◽

Cited By ~ 6

Author(s):

Jae-Won Lee ◽

Hyong-Soo Park ◽

Yong-Jo Park ◽

Myong-Cheol Yoo ◽

Tae-Il Kim ◽

...

Keyword(s):

Room Temperature ◽

Volume Fraction ◽

Ion Beam ◽

Etching Rate ◽

Dry Etching ◽

Ion Beam Etching ◽

Etching Profile ◽

Etching Parameters ◽

Etching Selectivity ◽

Reactive Ion Beam Etching

ABSTRACTDry etching characteristics of GaN using reactive ion beam etching (RIBE) were studied. Etching profile, etching rate and etching selectivity to a photoresist (PR) mask were investigated as a function of various etching parameters. Characteristics of chemically assisted reactive ion beam etching (CARIBE) and RIBE were compared at varied mixtures of CH4 and Cl2. A highly anisotropie etching profile with a smooth surface was obtained for tilted RIBE with Ch at room temperature. Etching selectivity to a PR was dramatically improved in RIBE and CARIBE when a volume fraction of CH4 to the mixture of CH4 and Ch was larger than 0.83.

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Etching Method of the Fabrication Optical Tapered Fiber and its Formula

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.145.520 ◽

2011 ◽

Vol 145 ◽

pp. 520-524 ◽

Cited By ~ 4

Author(s):

Yan Tang Huang ◽

Xiao Hua Wang ◽

Ri Yan Bao

Keyword(s):

High Efficiency ◽

Low Cost ◽

Etching Rate ◽

Fiber Surface ◽

Optical Power ◽

Etching Process ◽

Etching Time ◽

Mathematics Model ◽

Tapered Fiber ◽

Etching Method

Optical tapered fiber is one of the most high efficiency evanescent wave coupler for coupling light into and out the optical microcavity. We fabricated the tapered fiber with etching method in a designed groove with HF solution. This method was low cost, readily, and controllable. An etching groove had an oval in the middle and small V-shape towards both sides. HF solution was injected into the oval groove, while the deioned water was injected into the two V-grooves. Because of the solution diffusion, the etching rate was fast in the mid and decreased gradually towards both sides,the tapered fiber was fabricated. The optical power meter was monitoring the fiber transmission during the etching process. The transmission of the tapered fiber was 98%. We proposed a mathematics model to depict the etching process, containing the relationship between the diameter of tapered fiber and the concentration of the HF solution, the etching time, humidity, temperature. We supervised the optical intensity to deduce the tapered fiber diameter. Surface morphology with AFM was detected, the roughness of the tapered fiber surface is less than 1nm. As an evanescent coupler, we used the tapered fiber to transmit 980nm pump laser to couple to Er3+doped microsphere to stimulate 1557nm laser.

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Failure Analysis and Process Improvement for Through Silicon Via Interconnects

MRS Proceedings ◽

10.1557/proc-1156-d08-04-f06-04 ◽

2009 ◽

Vol 1156 ◽

Cited By ~ 4

Author(s):

Bivragh Majeed ◽

Marc Van Cauwenberghe ◽

Deniz Sabuncuoglu Tezcan ◽

Philippe Soussan

Keyword(s):

Failure Analysis ◽

Process Improvement ◽

Etching Rate ◽

Dry Etching ◽

Etching Process ◽

Thickness Variation ◽

Silicon Etching ◽

Soft Landing ◽

Etching Profile ◽

Etching Parameters

AbstractThis paper investigates the failure causes for slopped through silicon vias (TSV) and presents process improvement for implementing the slopped TSV for 3D wafer level packaging (WLP). IMEC is developing slopped and scaled generic approaches for 3D WLP. Previously we have reported on the integrated process flow for the slopped (TSV) and showed the feasibility of Parylene N as a dielectric material. In the TSV process discussed here, firstly 200mm device wafer is bonded facedown on a carrier using temporary glue layer and thinned by grinding. TSV's are realized by dry etching from the wafer backside, followed by dielectric deposition and patterning. Dielectric patterning is done at the bottom of the via on 100 microns thin silicon device wafer supported by the carrier. Finally, conformal plating is done inside the via to obtain the interconnections.This paper discusses the yield killer or failure causes in the slopped TSV process. There can be many parameter including silicon etch uniformity, dielectric etching at the bottom of the via and resist residue inside the via that can reduce the yield of the process. We report that one of the main factors contributing to the yield loss is silicon dry etching effects including non-uniformity and notching. Using standard Bosch etching process, notching at the interface between landing oxide and silicon has been observed. The notching cause a discontinuity at the bottom of the via resulting in no plating at the bottom interface.In this paper we report on a new via shape that is a combination of slopped and straight etching sequence to overcome the notching problem. Different parameters including influence of grinding marks, mask opening, wafer thickness variation, etching rate and etching profile across the wafer were investigated. The optimized design rules for mask opening and effect of individual etching parameters on the etching profile will be presented. In etching, firstly a sloped via with slope of 60 degrees is optimized with changing different etching parameters including different gasses and pressure. Slope via facilitates in subsequent dielectric deposition and sputtering processes. Secondly, a straight wall etching process based on Bosch process and soft landing step with longer passivation steps were investigated to obtain the notch free etching profile. The optimized etching process is notch free, very repeatable and total variation across different wafers is less then 2 percent for 100 micron target opening.This paper reports the failure analysis of TSV and discuses the processes improvement to obtain higher yielding vias. Different parameters that reduced the yield are discussed with main focus on notching effects during silicon etching. An improved and characterized, notch free uniform silicon etching across the wafer process based on two step etching is presented. An integration flow implementing the above optimized parameters with electrical yield will be detailed in the paper.

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Optimization of KOH etching process for MEMS square diaphragm using response surface method

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v15.i1.pp113-121 ◽

2019 ◽

Vol 15 (1) ◽

pp. 113 ◽

Cited By ~ 2

Author(s):

Norliana Yusof ◽

Badariah Bais ◽

Burhanuddin Yeop Majlis ◽

Norhayati Soin ◽

Jumril Yunas

Keyword(s):

Response Surface ◽

Response Surface Method ◽

Process Parameters ◽

Numerical Study ◽

Etching Rate ◽

Wet Etching ◽

Etching Process ◽

Etching Time ◽

Surface Method ◽

Koh Etching

<em><span>KOH wet etching is widely used in realizing MEMS diaphragm due to its low cost, safe and easy handling. However, wet etching process parameters need to be studied thoroughly in order to realize the desired shape and size of MEMS devices. This paper presents the numerical study and optimization of KOH etching process parameters using the response surface method (RSM). Face central composite design (FCC) of RSM was employed as the experimental design to analyze the result and generate a mathematical prediction model. From the analysis, the temperature was identified as the most significant process parameter that affects the etching rate, thus affecting the thickness and size of the diaphragm. The results of RSM prediction for optimization were applied in this study. Particularly, 45% of KOH concentration, temperature of 80°C, 1735 µm2 of mask size, and 7.2 hours of etching time were implemented to obtain a square MEMS diaphragm with thickness of 120 µm and size of 1200 µm2. The results of RSM based optimization method for KOH wet etching offers a quick and effective method for realizing a desired MEMS device.</span></em>

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Texture-Etched SnO2Glasses Applied to Silicon Thin-Film Solar Cells

Journal of Nanomaterials ◽

10.1155/2014/907610 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Bing-Rui Wu ◽

Sin-Liang Ou ◽

Shih-Yung Lo ◽

Hsin-Yuan Mao ◽

Jhen-Yu Yang ◽

...

Keyword(s):

Thin Film ◽

Surface Roughness ◽

Solar Cells ◽

Light Scattering ◽

Etching Rate ◽

Etching Process ◽

Thin Film Solar Cells ◽

Etching Time ◽

Silicon Thin Film ◽

Mixture Ratio

Transparent electrodes of tin dioxide (SnO2) on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

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