It is necessary to etch the thin films as a substrate to design a functional metal part on it. Normally, two types of etching processes are used to create such etched components, wet etching, and dry etching.
Wet etching
In this process, etched components can be created by immersing the masked substrate into a chemical solution to dissolve its unmasked part. It is the simplest and most cost-effective technology used for creating precision metal parts. You only need a container and etching chemical to etch the required material precisely by dissolving the material in the liquid solution. However, you will have to find a material that can be masked on the design of the metal part of your substrate so that its unmasked part can dissolve without dissolving the mask in the liquid chemical and etch the metal part precisely. Moreover, you will have to choose etching chemicals according to the type of material you want to etch.
When to use a wet etching process?
Wet etching can be the best method to etch substrates made of thin metal sheets or films. You can find various combinations of etching chemicals and masking materials to choose from as per your suitability. Though other etching processes like isotropic and anisotropic processes can also be used for etching substrates made of thin metal plates but there is a risk of undercutting or overcutting the layer of the mask which can be devastating for the idea creating precision etched components.
Dry etching
The technology of dry etching can further be divided into three categories- RIE or reactive ion etching, Sputter etching and vapor phase etching.
In RIE, several gasses are introduced in a reactor in which the substrate to be etched is placed. The mixture of gases is stricken by plasma by using the power of RF to break the molecules of gases into ions. These ions react with the surface of the substrate when accelerated to form another gas which can be used for reactive ion etching.The sputter etching is RIE without the reaction of ions. In sputter etching, these ions can etch the material to be etched without any chemical reaction if the energy of the ions is high enough.The equipment used for Vapor phase etching is simpler than the equipment used for RIE. The substrate to be etched is placed in this process in a chamber containing one or more gases to dissolve the substrate due to chemical reaction with the molecules of gas.
Such things make the process of dry etching very complicated as you have to adjust several parameters for balancing physical and chemical etching.
When to use a dry etching process?
Though dry etching is a costlier process than wet etching still you can use it to create etched components if you are worried about the resolution of the structure of thin film or you want deep etching in the vertical sidewalls of the substrate.
Thus you can use different etching methods to produce etched components according to your requirements and budget.