Bath etching

Atz-ammoniak, n. caustic ammonia (ammonium hydroxide), ammonia water. artikel, m. (Calico) discharge style. bad, n. etching bath. 

Use the rinse bath water again in a different area. For example, if there is a line with a chromic acid etch bath followed by counter-flow rinse baths and a neutralizer bath followed by counter-flow rinse baths, use the dirtiest rinse after the neutralizer bath and pipe it to the rinse baths after the chromic acid tank. This saves water and reduces sludge. 

When using a scrubber without any etching step (HF), an additional etching bath can be implemented in order to remove the damaged layer. 

It is easiest to etch tips if a long (1-2 cm.) section of wire is available for immersion into the etch bath. The wire to be etched is examined periodically under the light microscope until the tip cannot be resolved at 500-foId magnification. A carbon rod is satisfactory for the other electrode, or a platinum crucible containing the etch solution may be used. After final etching, tips and assemblies are rinsed in distilled water. 5-15 mil wires are satisfactory, but smaller sizes can be used. 

The plating bath can also contain impurities which cannot be removed by ordinary filtration, such as solubilized metals dragged in from a previous etching bath (Foecke 1989). Ion exchange (IE) treatment can often be used for removing solubilized metals, although IE systems are fairly expensive compared to standard filtration technologies. 

A distinction can be made between a positive and a negative resist, according to the action of light. In a positive working resist the monomer is deposited on the copper surface in the form of a viscous liquid. It is then irradiated through a mask (this is simply a drawing of the required pattern on a transparent sheet) and polymerization takes place only at the exposed places. The unirradiated liquid monomer is then washed away in a suitable solvent, and the exposed copper can be dissolved in an etching bath. Finally the protective polymer layer is removed by chemical or mechanical means, and the printed circuit is ready. 

In a negative working resist the monomer is first polymerized over the entire copper surface, then the protective polymer layer is irradiated through the mask. In the irradiated areas the polymer is degraded into smaller units and becomes soluble it can then be removed by treatment with a suitable solvent and the etching bath will attack this exposed copper. 

In one report, surfactant was added to yield better dimensional consistency and smoothness of channel edges [626]. In another case, glycerol was added to the HF etching bath [729]. 

To remove precipitated particles in the BOE process, the substrates were removed every 2-5 min and dipped in a 1 M HC1 solution for 10-20 s. Adding HC1 directly into the HF etch bath will have a similar effect [105,109-111]. 

Finally, track-etched MF membranes are made from polymers, such as polycarbonate and polyester, wherein electrons are bombarded onto the polymeric surface. This bombardment results in sensitized tracks, where chemical bonds in the polymeric backbone are broken. Subsequently, the irradiated film is placed in an etching bath (such as a basic solution), in which the damaged polymer in the tracks is preferentially etched from the film, thereby forming cylindrical pores. The residence time in the irradiator determines pore density, and residence time in the etching bath determines pore size. Membranes made by this process generally have cylindrical pores with very narrow pore-size distribution, albeit with low overall porosity. Furthermore, there always is the risk of a double hit, i.e., the etched pore becomes wider and could result in particulate penetration. Such filter membranes are often used in the electronic industry to filter high-purity water. 

The etch rate of quartz depends on the crystallographic orientation of the surface. Table 4.3 shows the etch rate on the surface with different orientations. The difference among the four orientations can be as large as 1000-fold. The etched surface morphology is a function of solution composition and temperature, particularly the concentration of positive ions. An etching bath with added gives terraces but no pits, a... 

V. Harrap, Equal etch baths of Si3N4 and SiOa utilizing HE dilution and temperature dependence, in Semiconductor Silicon, H. R. Hoff and U. Burgess (eds.), p. 354, Electrochemical Society, Peiming-ton 1973. 

Desalination of seawater and brackish water Electroplating rinse water Etch bath rinse water... 

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