Why Particle Removal is Essential in Silicon Wafer Cleaning

The effective removal of particles and contaminants is vital part of silicon wafer cleaning. Particles and such other impurities that are either deposited on wafer surfaces or are left over from the previous process stages, can cause defects in the final semiconductor product. Even the tiniest particles can block etching and have a negative effect in the diffusion process, resulting in semiconductor circuit that is either defective or having reduced quality and life expectancy.

The goal of all silicon wafer cleaning processes is to leave the silicon wafer surface intact along with removing contaminating particles at the same time. Specialized equipment is required for various cleaning processes which include traditional standard processes that can be used together with new technologies aimed at removing even the smallest particles.

The different cleaning methods which are used at different stages of the silicon wafer fabrication process include the following:

• RCA clean process – consists of two steps: SC1 (which removes organic particles) and SC2 (which removes metallic residues and particles). Each of the steps uses different cleaning chemicals to remove residues or particles.
• Piranha cleaning process – removes large amounts of organic residues such as photoresist. It uses a corrosive mixture of sulfuric acid and hydrogen peroxide, which must be handled with care.
• Megasonic cleaning – removes particles and other contaminants using microscopic cavitation bubbles generated by a megasonic cleaning system.
• The Ozone cleaning process–uses ozone to convert organic particles and contaminants to carbon dioxide. 

Pre-diffusion clean is one of the most critical silicon wafer cleaning processes that takes place just before the wafers are placed in the diffusion oven. Any of the cleaning methods listed above or a combination of these can be used to ensure that wafers are free of particles so diffusion will be even and consistent.

The great news is that Modutek, a company with over 30 years of experience in providing semiconductor manufacturing solutions, offers wet bench technology which supports all of the above-mentioned cleaning methods. Their silicon wafer cleaning systems can come in manual, semi-automatic or fully automatic. They are available in standard configurations but Modutek can also design custom products to meet the client's cleaning specifications.

Silicon wafer cleaning is important for achieving quality wafers. Read the complete article “Why Particle Removal Is Essential in Silicon Wafer Cleaning” for more information. If you have questions or would like to a get a free consultation or quote, call 866-803-1533 or email Modutek@modutek.com.