Silicon is most well-known as a semiconductor material, but because of its high mechanical strength and ease of processing, it is also commonly used in a wide variety of devices such as MEMS, optical components, micro-channel devices, and packaging. There are many methods for processing silicon, such as dry etching, wet etching, and laser processing, each of which has advantages and disadvantages that should be evaluated carefully and compared.

The processing method called Si-DRIE is a type of plasma dry etching. The etching technology cultivated for semiconductors has improved the processing of mechanical devices and has been proven to allow faster and deeper etching of features with higher aspect ratios. Among Si-DRIE techniques, there are three main process types: the Bosch process, Non-Bosch processes, and Cryogenic etching. Since silicon and fluorine atoms react very easily, processing silicon using a simple fluorine chemistry process results in an isotropic profile. Therefore, the key for increasing the verticality and aspect ratio for any of the three process types is to suppress lateral etching and develop an anisotropic process.

The Bosch process is a technique which alternates between depositing a protective film on the sidewall using a C₄F₈ plasma and etching the bottom of the trench or hole with SF₆. The Non-Bosch process is a technique of simultaneously depositing a protective layer on the sidewall and directionally etching the bottom of the feature with ions. Cryogenic etching is a method similar to the Non-Bosch process and suppresses the chemical reaction of Si and F atoms on the sidewall by lowering the substrate temperature to that of liquid nitrogen.

The Bosch process has excellent selectivity and is capable of high aspect ratio etching and is often used for MEMS and packaging. On the other hand, the Non-Bosch process has smooth sidewalls with positive taper angle, which is useful for through-silicon vias (TSV). Additionally, the angle of the mask can be transferred into the etched material, which is often done for optical parts such as lenses. The Cryogenic etching process can achieve the selectivity of an oxide mask vs silicon equivalent to that of the Non-Bosch process. One drawback of this technique is that photo resist masks cannot be used due to the extremely low temperature of the process.

On Samco’s flagship RIE-800iPB deep reactive ion etching (DRIE) system it is possible to utilize both the Bosch and Non-Bosch processes on the same system. The Bosch process enables deep and high aspect features along with extraordinary levels of selectivity to the mask. The Non-Bosch process provides deep etching with smooth sidewalls and a flexible range of taper angles. Substrate temperatures between -10°C and 20°C are controlled via liquid cooling of the bias electrode combined with electrostatic chucking (ESC) and substrate back side He gas cooling. By combining these two methods, the RIE-800iPB delivers versatile, efficient, gentle and affordable solutions for MEMS, TSV, packaging, and other applications. It’s been exciting to see the continual evolution of our Si DRIE solutions as we incorporate new customer requirements into the system design. Do you have a process challenge? Give our experienced process engineers the opportunity to meet your challenge and exceed your expectations.

What the Samco Si-DRIE Can Do?
Anisotropic Silicon Deep Reactive Ion Etching process using the Bosch Process and Non-Bosch Process enables trench, hole and pillar fabrication for various device applications. These are some examples of structures fabricated using the Bosch Process. For more details, please visit the processes below.

• Bosch Process for Micro Fablication
• Non Bosch Process for through-silicon via (TSV)

Samco Product Portfolio for Silicon Deep Reactive Ion Etching

Our systems have industry-leading process capabilities, and the product lineup covers both R&D and production.

• Si Deep Reactive Ion Etching (DRIE) Systems
  

Sensitivity of Piezoelectric Ultrasonic Microsensors with Sol-Gel Derived PZT Films Prepared through Various Pyrolysis Temperatures

Kaoru Yamashita, Shota Nakajima, Jo Shiomi and Minoru Noda
Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
2017 IEEE International Meeting for Future of Electron Devices, Kansai (IMFEDK), Kyoto, Japan, 2017, pp. 108-109.

In this paper, MEMS ultrasonic microsensors with sol-gel derived PZT piezoelectric diaphragm was fabricated. In device fabrication, Samco silicon Deep RIE etcher RIE-400iPB was used to form the thin diaphragm structure by silicon plasma etching from the wafer backside.
Stress control of PZT thin film was carried out to investigate high ultrasonic sensitivity of the devices.

Samco provides silicon deep RIE etching technologies utilizing the Bosch Process to R&D labs for MEMS device and TSV processing applications. For more information on our process technologies of deep silicon etching, please visit the process data page below.
Silicon Deep RIE Process Data

Bacterial population solitary waves can defeat rings of funnels

Ryan J Morris¹, Trung V Phan², Matthew Black³, Ke-Chih Lin⁴, Ioannis G Kevrekidis⁵, Julia A Bos³ and Robert H Austin^2
1 School of Physics & Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
² Department of Physics, Princeton University, Jadwin Hall, Princeton, NJ 08544, United States of America
³ Lewis-Sigler Institute for Integrative Genomics, Princeton, NJ 08544 United States of America
⁴ Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, United States of America
⁵ Department of Chemical and Biological Engineering and PACM, Princeton University, Princeton, NJ 08544, United States of America
New Journal of Physics (2017) Volume 19 035002

Circular corral for bacteria made of rings of concentric funnels was fabricated. Nanoslits were etched on a silicon wafer using Samco Deep RIE Tool RIE-800iPB at Princeton University.

Samco offers a couple of silicon Deep RIE systems for R&D and production. Please see the product page below.
Silicon Deep RIE Systems

Also, for more details of Samco silicon deep RIE process capabilities, please visit the process solution page below.
Slicon Deep RIE Technology for MEMS and TSV Processing

Fabrication of 25 μm-filter microfluidic chip on silicon substrate

Nguyen Ngan Le^1,2, Kim Khanh Huynh¹, Thi Cam Hue Phan¹, Thi My Dung Dang¹ and Mau Chien Dang^1
1 Laboratory for Nanotechnology, Vietnam National University in Ho Chi Minh City, Community 6, Linh
Trung Ward, Thu Duc District, Ho Chi Minh, Vietnam
² University of Science, Vietnam National University in Ho Chi Minh City, 227 Nguyen Van Cu Street,
District 5, Ho Chi Minh City, Vietnam
Adv. Nat. Sci.: Nanosci. Nanotechnol. 8 (2017) 015003

A microfluidic chip device was fabricated using deep silicon etching technology of the Bosch Process. Samco Deep RIE Tool RIE-200iPB was used for silicon etching over silver hard mask. With optimization of process recipe in the silicon etching, vertical silicon channel profile was fabricated.

For more details of our deep RIE process capabilities, please visit the pages below.
Silicon DRIE (Deep Reactive Ion Etching) for MEMS and TSV
Deep Silicon Trench/Via Hole/Pillar Etching using the Bosch Process

Influence of top electrodes to vibration modes in impulse responses of MEMS piezoelectric diaphragms for ultrasonic microsensors

T. Nishioka, T. Nishiumi, K. Yamashita and M. Noda
Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, 606-8585, Japan
2016 IEEE International Meeting for Future of Electron Devices, Kansai (IMFEDK), Kyoto, 2016, pp. 1-2.
doi: 10.1109/IMFEDK.2016.7521705

Ultrasonic micro sensors with piezoelectric diaphragms were fabricated to investigate the relationship between vibration mode and device structure of electrode and the diaphragms. Samco Deep Reactive Ion Etching system was used for anisotropic silicon plasma etching in the Bosch Process over SiO₂ mask.

For more details of our silicon plasma etching capabilities, please visit the process data pages below.

Silicon Plasma Etching Process Data (RIE and ICP-RIE)
Silicon Deep RIE Process Data Using the Bosch Process

Tensile fracture of integrated single-crystal silicon nanowire using MEMS electrostatic testing device

Toshiyuki Tsuchiya , Tetsuya Hemmi, Jun-ya Suzuki, Yoshikazu Hirai, Osamu Tabata
Department of Micro Engineerng, Kyoto University, Kyotodaigaku-Katsura C3, Nishikyo-ku, Kyoto 615-8540, Japan
Procedia Structural Integrity (2016) 2 Pages 1405–1412

Samco silicon Deep RIE system at Kyoto University was used for silicon nanowire fabrication by combination of two types of silicon etch processes (the Bosch Process) with coarse and fine scallops. Using the unique silicon plasma etching processes, silicon nanowire structures were successfully fabricated on a SOI wafer.

Kyoto University is one of Samco Deep RIE system customers for MEMS device research.
For more details of our silicon Deep RIE process technologies, please visit the process data pages below.
Silicon Deep RIE for MEMS & TSV Applications
Deep Silicon Etching Using the Bosch Process – Trench, Via Hole & Pillar Etching

Also, For more information of our silicon Deep RIE systems, please visit the product page below.
Silicon Deep RIE Systems

Mesoporous silica layer on plasmonic array: light trapping in a layer with a variable index of refraction

Shunsuke Murai^{1, 2}, Hiroyuki Sakamoto¹, Koji Fujita¹, and Katsuhisa Tanaka^1
1 Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
² PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
Optical Materials Express Vol. 6, Issue 9, pp. 2736-2744 (2016) doi: 10.1364/OME.6.002736

Plasmonic array was fabricated using nanoimprint technology. First, silicon mold consisting of a periodic square array was fabricated using silicon deep etching. Samco silicon DRIE system at Kyoto University was used for the mold fabrication. Then, Samco ICP etch system was used for pattern transfer by aluminum dry etching over photoresist pattern fabricated by the nanoimprint process.

Methods of creating and observing atomically reconstructed vertical Si{100}, {110}, and {111} side-surfaces

Azusa N. Hattori^1,2, Shohei Takemoto³, Ken Hattori³, Hiroshi Daimon¹ and Hidekazu Tanaka^1
1 Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
² JST-PRESTO, Kawaguchi, Saitama 332-0012, Japan
³ Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan
Appl. Phys. Express (2016) 9 085501

Samco silicon Deep Reactive Ion Etch (DRIE) system at Osaka University was used for silicon nano-scale structure fabrication.

For our process examples and capabilities of deep silicon etching using Bosch Process, please visit the pages below.
Deep Silicon Trench/Via Hole Etching using Bosch Process
Si DRIE (Deep Reactive Ion Etching) for MEMS and TSV

Athermal Hybrid Silicon/Polymer Ring Resonator Electro-optic Modulator

Feng Qiu¹, Andrew M. Spring¹, Hiroki Miura², Daisuke Maeda³, Masa-aki Ozawa³, Keisuke Odoi³, and Shiyoshi Yokoyama^{1, 2
1} Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-koen Kasuga-city, Fukuoka 816-8580, Japan
² Department of Molecular and Material Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga-city, Fukuoka 816-8580, Japan
³ Nissan Chemical Industries, LTD, 2-10-1 Tuboi Nishi, Funabashi, Chiba 274-8507, Japan
ACS Photonics
DOI: 10.1021/acsphotonics.5b00695

Silicon plasma etching was performed using Samco silicon DRIE system to fabricate a hybrid silicon/polymer ring resonator electro-optic (EO) modulator.
For our process examples of silicon plasma etching, please visit process data page below.
Si Dry Etching Process (RIE, ICP-RIE or XeF₂ Etch)
Deep Silicon Trench/Via Hole Etching using Bosch Process
Si DRIE (Deep Reactive Ion Etching) for MEMS and TSV

Plasmonic arrays of titanium nitride nanoparticles fabricated from epitaxial thin films

Shunsuke Murai, Koji Fujita, Yohei Daido, Ryuichiro Yasuhara, Ryosuke Kamakura, and Katsuhisa Tanaka
Shunsuke Murai^1,2 Koji Fujita^1,3> Yohei Daido¹ Ryuichiro Yasuhara¹ Ryosuke Kamakura¹ and Katsuhisa Tanaka^1
1 Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Optics Express Vol. 24, Issue 2, pp. 1143-1153 (2016) •doi: 10.1364/OE.24.001143

Titanium Nitiride (TiN) nanoparticle arrays were fabricated using nanoimprint technologies.
For nanoimprint mold fabrication, Samco deep silicon etching system at Kyoto University was used for nanostructure fabrication on silicon molds. After transferring of the silicon mold pattern to photoresist on TiN substrate, Samco ICP etching system at Kyoto University was used for TiN dry etching over photoresist to fabricate TiN nanoparticle arrays.