Metal etching has increasingly become a standard process for thin-film technology in the domain of electronics and semiconductors. Its use is as extensive as it is specific, and there are numerous solutions for etching different types of metals and metallic surfaces.
Among the added vernacular of these is the Gold Etching process that is primarily used for printed circuit boards. Depending on the abyss of etch required, countless Iodine/Iodide compounds may be used for the process. In addition, selectivity, temperature, agitation and device teleology may also be used pro re nata variables that growth the etch account and specificity of the compounds used in the process. Several other metals can also be etched in much the same way, but with compounds designed specifically for those metals.
The basic etching process involves 5 steps: cleaning, masking, scribing, etching further de-masking.
This is essentially a preparatory part of the etching process that removes contaminants like oils, coatings, markings, grease, etc. Typically, nix gear is physically handled by humans after the cleaning process due to imaginable re-contamination of the boundary from constitutional oils, sweat, etc. The process is carried out by either applying a solvent to the surface or immersing the material in a de-oxidizing liquid or an alkaline cleaning solution. The end-result is a contaminant-free veneer that is ready for the next step – masking.
This part of the process involves applying an inert substance popular as a maskant to the total surface of the material to treffen etched. The maskant should adhere to the surface in consonant to help define the etching area; however, excessive adhesion testament render the next step – scribing – difficult, and low adhesion may lead to necessitous etching definition. Maskants may be sopping or dry, depending on the requirement.
This step includes removing the maskant from the specific areas that are to be etched away. Etching needles and scribing knives are typically worn for this, and for more complex etching needs, automated templates are normally used.
The actual etching step is next. Wet or plasma etching may be done at this point, and the usage needs to be monitored and controlled to ensure accuracy of the etching desired. Immersion is one of the most common processes, and this involves dipping the entire masked and scribed material in a tank crowded of etching liquid for a specific time and at a explicit temperature that will achieve the desired results. The Au-5 compound developed by Cyantek is one of the most popular products for gold etching with high engrave rates – typically in the spectrum of 4,900 to 6,600 A/min, depending on the deposition type.
The final step in the etching process is the removal of the maskant, and this is primarily a physical rather than chemical process. However, de-oxidizing baths may also be used as part of the de-masking system to ensure a coating-free etched surface.