Silicon plasma etching

The structures were etched using a time-multiplexed inductively coupled plasma etch (Figure 3.21). On the back side of such a stmctured silicon wafer holes were... 

Microfabrication involves multiple photolithographic and etch steps, a silicon fusion bond and an anodic bond (see especially [12] for a detailed description, but also [11]). A time-multiplexed inductively coupled plasma etch process was used for making the micro channels. The microstructured plate is covered with a Pyrex wafer by anodic bonding. 

Figure 13.6. Effects of stress concentration on breakability. Scanning electron micrographs (top frames) showing breaks of anchored silicon beams etched with (a) plasma, (b) KOH and isopropyl alcohol, and (c) KOH and optical micrographs (bottom frames) of printing results that demonstrate the relative ease of breakability, or the ability for a stamp to separate elements from the anchoring structures in each system. (Reprinted with permission from Ref. 54. Copyright 2007 American Institute of Physics.)...

Plasma etching, of silicon, 22 492 Plasma FPDs, 22 259 Plasma fractionation, 12 128-159 economic aspects of, 12 147-150 health, safety, and environmental factors related to, 12 153... 

The factor f reduces the oscillation amplitude symmetrically about R - R0, facilitating straightforward calculation of polymer refractive index from quantities measured directly from the waveform (3,). When r12 is not small, as in the plasma etching of thin polymer films, the first order power series approximation is inadequate. For example, for a plasma/poly(methyl-methacrylate)/silicon system, r12 = -0.196 and r23 = -0.442. The waveform for a uniformly etching film is no longer purely sinusoidal in time but contains other harmonic components. In addition, amplitude reduction through the f factor does not preserve the vertical median R0 making the film refractive index calculation non-trivial. 

The steam reformer is a serpentine channel with a channel width of 1000 fim and depth of 230 fim (Figure 15). Four reformers were fabricated per single 100 mm silicon wafer polished on both sides. In the procedure employed to fabricate the reactors, plasma enhanced chemical vapor deposition (PECVD) was used to deposit silicon nitride, an etch stop for a silicon wet etch later in the process, on both sides of the wafer. Next, the desired pattern was transferred to the back of the wafer using photolithography, and the silicon nitride was plasma etched. Potassium hydroxide was then used to etch the exposed silicon to the desired depth. Copper, approximately 33 nm thick, which was used as the reforming catalyst, was then deposited by sputter deposition. The reactor inlet was made by etching a 1 mm hole into the end... 

A representative sample of terpolymers was exposed to a variety of etchants for polysilicon and silicon dioxide, and the results are given in Table V. The ratio of the etch rate of the substrate to the etch rate of the resist must be at least 2 1 for the resist to be a viable etch mask. Inspection of Table V, shows that the materials examined are unacceptable for only the QFj — CF3CI (4 1) plasma. The etch rates are comparable to those for PMMA the a-keto-oxime exhibits essentially no effect on that rate and the nitrile affords a slight decrease in the plasma etch rate. The etch rates of some commercially available materials are shown for comparison. 

Recent investigations in the field of plasma etching have almost universally found that surfaces subjected to ion bombardment (e.g., the target surface in Fig. 1) react (i.e., etch) much more rapidly than those which are held near plasma potential. Examples of this type have been reported by Hosokawa et al. for the halocarbon etching of silicon and by Holland and Ojha for the oxygen plasma-etching of carbon. Several systems exhibiting this type of behavior have also been observed in our laboratory . 

Plasma etching is widely used in semiconductor device manufacturing to etch patterns in thin layers of polycrystalline silicon often used for metal oxide semiconductor (MOS) device gates and interconnects (see Plasma technology). 

The distribution of impurities over a flat silicon surface can be measured by autoradiography or by scanning the surface using any of the methods appropriate for trace impurity detection (see Trace and residue analysis). Depth measurements can be made by combining any of the above measurements with the repeated removal of thin layers of silicon, either by wet etching, plasma etching, or sputtering. Care must be taken, however, to ensure that the material removal method does not contaminate the silicon surface. 

Plasma etching is a well-established technology for microchip fabrication, involving the removal of silicon with a beam of fluorine atoms generated by high energy electrical excitation of simple fluorocarbons, notahly carbon tetrafluoridc, chlorotrifluoromethanc. trifluorometh-... 

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