Microelectromechanical Systems or more commonly known as MEMS is a technology designed for very small devices. It is made up of components between 1 to 100 micrometers in size; it is being used in numerous applications such as in electronics, biotechnology, communication, and medicine.
Fabrication of MEMS can be performed using several processes such as deposition, patterning, and etching. However, in this content, we are going to give our focus on etching process and its various types.
When it comes to MEMS etching, it can be done using several processes, and they can be divided into two broad categories – the wet and dry etching.
Dry etching – the material in this process is dissolved using reactive ions or a vapor phase enchant. One main advantage of this process is that it is capable of defining small feature size that is less than 100 nm. However, it has several disadvantages as well like high cost, low throughput, poor selectivity, and the potential for radiation damage.
Sample of dry etching
Xenon fluoride etching – this particular process was first used in 1995 and is primarily utilized for releasing metal and dielectric structures by undercutting silicon.
Plasma etching – a dry etching process that includes the generation of reactive species, the diffusion of these species, and then adsorption. (note: etch species is also known as plasma source)
Wet etching – in this process, the material is dissolved through immersion using chemical solution inside a wet bench. It offers a number of advantages as it is easy to implement, has high etching rate, low cost, and good selectivity for most materials. However, it has some disadvantages as well such as the inadequacy for defining feature size that is less than one (1) micrometer.
Sample of wet etching
Isotropic etching – known as the non-directional removal of material from a substrate in a chemical process with the help of a substance/mixture called an etchant.
Hydrofluoric acid etching – this process uses an aqueous etchant for silicon dioxide.
There are quite a number of processes involved in etching – each has its own advantages and limitations. One thing is clear, however – etching plays a vital role in micro fabrication, which is essential to the production of devices needed in the industry.
Paul Drake has had several years of experience working in a high tech facility before venturing on the Internet as a content writer. He uses his prior knowledge in writing industry-related topics, including etching process for MEMS. He also runs a personal blog of the same niche.