Chemical etching cleaning

Chemical etching. Cleaned parts are immersed for 10 to 30 s into a fluoronitric mixture (25 to 35 wt.% HNO3 with 15 to 30 cm HF per liter) followed by a thorough rinse with deionized water. 

Chemical etching (cleaning) The removal of material by chemical reaction with a fluid (wet chemical etching) or vapor (vapor etching) to produce a soluble or volatile reaction product. The etch rate is affected by the density, porosity, and composition of the film. 

To treat all the different wet processes for silicon wafers developed in the last five decades exhaustively would make up a book of its own. However, a few basic aspects are important, because chemical etching of silicon is closely related to the electrochemical behavior of Si electrodes, especially to the OCP condition. A brief overview of the most common etching and cleaning solutions will be given, with emphasis on the electrochemical aspects. 

For a compound semiconductor to be useful as a substrate in studies of electrodeposition, it is desirable that clean, unreconstructed, stoichiometric surfaces be formed in solution prior to electrodeposition. For CdTe, the logical starting point is the standard wet chemical etch used in industry, a 1-5% Brj methanol solution. A CdTe(lll) crystal prepared in this way was transferred directly into the UHV-EC instrument (Fig. 39) and examined [391]. Figure 66B is an Auger spectrum of the CdTe surface after a 3-minute etch in a 1% Br2 methanol solution. Transitions for Cd and Te are clearly visible at 380 and 480 eV, respectively, as well as a small feature due to Br at 100 eV. No FEED pattern was visible, however. As described previously, a layer of solution is generally withdrawn with the crystal as it is dragged (emersed) from solution (the emersion layer). After all the solvent has evaporated, the surface is left with a coating composed of the... 

Commonly used adhesives for both PET and PBT substrates are isocyanate cured polyesters, epoxies, and urethanes. Surface treatments recommended specifically for PBT include mechanical abrasion and solvent cleaning with toluene. Gas plasma surface treatments and chemical etch have been used where maximum strength is necessary. 

Often reports leave out the detailed lithographic steps, the chemical etches, the plasma-etching conditions, cleaning solutions used, and temperature cycles involved. These factors, especially with regard to the reverse leakage current of p-n junctions and Schotlky barriers, may be very significant, but their significance is not known. 

Following [102], sagittal midcoronal sections (thickness of 2 mm) of sterilized teeth are prepared by polishing using a series of Si02 papers and a water-based diamond paste to 0.25 pm (Buehler, Lake Blu., IL). The sample surface is cleaned by an ultrasonic treatment in water for 10 s. Wet chemical etching of the specimens in... 

Figure 6.11 Scanning electron micrographs of tape and solvent cleaning. Reprinted with a single-crystalline hexagonal nanohole array permission from Lee, S.H., Bantz, K.C., formed from a template of 600 nm polystyrene Lindquist, N.C. et al. (2009) Langmuir, 25, spheres by size reduction using reactive ion 13685. Copyright 2009 American Chemical etching followed by deposition ofSOnm of Ag Society.

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