Silicon Reactive Ion Etching for Micromachining Applications (original) (raw)
Related papers
A survey on the reactive ion etching of silicon in microtechnology
Journal of Micromechanics and Microengineering, 1996
This article is a brief review of dry etching as applied to pattern transfer, primarily in silicon technology. It focuses on concepts and topics for etching materials of interest in micromechanics. The basis of plasma-assisted etching, the main dry etching technique, is explained and plasma system configurations are described such as reactive ion etching (RIE). An important feature of RIE is its ability to achieve etch directionality. The mechanism behind this directionality and various plasma chemistries to fulfil this task will be explained. Multi-step plasma chemistries are found to be useful to etch, release and passivate micromechanical structures in one run successfully. Plasma etching is extremely sensitive to many variables, making etch results inconsistent and irreproducible. Therefore, important plasma parameters, mask materials and their influences will be treated. Moreover, RIE has its own specific problems, and solutions will be formulated. The result of an RIE process depends in a non-linear way on a great number of parameters. Therefore, a careful data acquisition is necessary. Also, plasma monitoring is needed for the determination of the etch end point for a given process. This review is ended with some promising current trends in plasma etching.
Fabrication of Reactive Ion Etching Systems for Deep Silicon Machining
IEEJ Transactions on Sensors and Micromachines
Reactive ion etching (RIE) systems using capacitively coupled plasma (CCP) and inductively coupled plasma (ICP) sources with SF6 gas have been developed for deep silicon machining with high aspect ratio. The developed RIE systems demonstrated high etch rate (2.3 and high selectivity (1700) for a sputtered nickel mask in silicon etching. A large capacity turbo molecular pump (TMP) with a small etching chamber was used to realize a low pressure with a high flow rate of etching gas. A circulatory cooling apparatus was used for cooling a silicon wafer. Etch rate showed uniformity within 10% for the area of 50cm2. Using the RIE system, we succeeded to etch a thick silicon wafer vertically through the thickness with an aspect ratio greater than 10. The RIE can be applied to fabricate three-dimensional silicon microstructures.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1997
A novel highly anisotropic room-temperature process for silicon etching, using mixtures of SF 6 and CHF 3 gases is presented. The etch rate, selectivity, dc bias voltage and anisotropy as a function of the reactive ion etching conditions ͑mixture composition, pressure and rf power͒ are discussed. Excellent anisotropy combined with clean, damage-free surfaces and etching uniformity and reproducibility have been achieved. It was thus possible to fabricate free standing silicon wires with diameter less than 50 nm and with aspect ratios up to 50:1. Optical emission spectroscopy, ex situ x-ray photoelectron spectroscopy and atomic force microscopy were employed as plasma gas phase and surface diagnostics.
High aspect ratio micro- and nano-machining of silicon using time-multiplexed reactive ion etching
Journal of Micromechanics and Microengineering, 2011
A low-density plasma reactive ion etching is reported to realize high aspect ratio silicon nanorods on silicon substrates. Aspect ratios with values more than 100 are obtained for features below 200 nm. The process uses a mixture of three gases of hexaflourosulfide, hydrogen and oxygen in a reactive ion etching system with a programmed passivation and etching sub-cycles. Using these three gases in both etching and passivation sub-cycles allows deep silicon etching with high rates, with no need of an inductive coupling plasma source and a special cooling system. The mask undercut can be around 30 nm, despite a high etch rate of 0.8-1.1 μm min −1. X-ray photoelectron spectroscopy and scanning electron microscopy have been used to investigate the prepared samples. Also, the Knudsen transport model has been applied to the etching process which results in a value of 0.23 for the 'S' value as the probability for the reaction at the bottom of the craters.
Suitability of reactive ion etching on 0.13 micro_m silicon technology
This paper reports on the possibility of using reactive ion etching in selective clean etching in 0.13m silicon technology. Trifluromethane and tetrafluromethane plasmas were used to etch a layer consists of aluminum interconnections buried in a silicon dioxide dielectric layer. As the aim is to find the appropriate parameters for silicon dioxide etching, the process is carried out under different conditions by varying, gas flow, RF power an additional agents. Results show that RIE is very effective at the targeted scale in terms of both dimensionality and etch selectivity.
Journal of Micromechanics and Microengineering, 1995
Very deep trenches (up to 200 pm) with high aspect ratios (up to 10) in silicon and polymers are etched using a fluorine-based plasma (SFd02/CHF3). Isotropic, positively and negatively (i.e. reverse) tapered as well as.fully vertical walls with smooth suriaces are achieved by controlling the plasma chemistry. A convenient way to find the processing conditions needed for a vertical wall is described the black silicon method. This new procedure is checked for three different reactive ion etchers (RIE), two parallel-plate reactors and a hexode. The influence of the RF power, pressure and gas mixture on the profile will be shown. Scanning electron microscope (SEM) photos are included to demonstrate the black silicon method, the influence of the gases on the profile, and the use of this method in fabricating microelectromechanical systems (MEMS).
Process characterisation of deep reactive ion etching for microfluidic application
International Journal of Nanotechnology, 2018
The goal of this paper is to investigate the influence of parameters of the Bosch deep reactive ion etching (DRIE) process on etched surface profile, sidewall profile and etch rate of micrometre silicon features. By investigating these parameters, we found the conditions to obtain smooth sidewall, high etch rate and balance of chemical and physical etching in the DRIE process. In this paper, the silicon surface was covered by a thin silver patterning, created by lift-off, as a hard mask for the DRIE process. The etched samples were characterised by optical microscopy and mechanical profilometry. The results show smooth sidewall of 136 µm-deep silicon trenches obtained at a high etch rate of 4 µm/min using 5 sccm C 4 F 8 , 8 sccm O 2 and 24 W of bias power.