Important Facts About Piranha Etch Cleaning


July 16, 2021

Shop Now

One of the most critical steps in manufacturing semiconductors and MEMS involves the cleaning process used for silicon wafers. The silicon wafer supplier makes sure that chemical and particle impurities are removed from each wafer without causing damage to its substrate or surface. One of the cleaning techniques they use is called the piranha etch cleaning method. Also known as piranha solution, this type of cleaning method uses a mixture of sulfuric acid and hydrogen peroxide to effectively eliminate organic matter from the surface of each wafer. Besides removing most organic photoresist residues, piranha etch also makes its surfaces compatible with water by adding OH groups or hydroxylating them.  

choosing a silicon wafer supplier

Piranha Etch Cleaning: A Closer Look

It’s Highly Explosive

It’s important to note that piranha etch is highly explosive. When the solution is mixed, it releases heat that can cause solution temperatures to rise up to 120°C. For this reason, manufacturers must allow the solution to cool before they apply heat. Violent boiling may also result from a sudden increase in temperature. Since the maximum concentration for peroxide in water solution is about 35%, explosions may occur if it exceeds 50%.  

It Self-Decomposes

Manufacturers should use it soon after it’s prepared. It’s never a good idea to store piranha solutions because hydrogen peroxide self-decomposes. While it undergoes the process of self-decomposition, it gives off oxygen gas that causes the waste bottle to pressurize and break.   Instead of accumulating waste piranha solution in containers, it’s best to neutralize it and dispose of it as soon as possible.

It Should Be Handled With Extreme Caution

Since Piranha cleaning solutions are extremely dangerous to handle, extreme caution is required. The person who’s handling it must wear personal protective equipment which consists of the following:

  • Safety glasses and full-face shield  
  • Heavy duty rubber gloves
  • Acid apron on top of a lab coat
selecting a silicon wafer supplier

Looking For a Silicon Wafer Supplier?

Wafer World has been serving satisfied clients across the globe for the past 25 years. Contact us today to get high-quality silicon wafers at the best price possible.

Wafer World Banner