Why Teflon Tanks Are Used with the KOH Etching Process

KOH etching is more preferred compared to many other silicon wafer fabrication methods because it works rapidly and reliably, while handling of the chemicals is relatively safe. The KOH etching process controls the etching speed by relying on a contamination-free environment and using the temperature and KOH concentration.

Only Teflon tanks are used in this process because Teflon is stable and doesn't deteriorate or corrode from using KOH etching.

The KOH etching process controls allow precise and repeatable temperature controls for positive fabrication results and high-quality production. KOH etching in Teflon tanks, along with temperature control, is an exceptional process for silicon wafer nanostructure fabrication in both manufacturing facilities and research environments.

KOH or potassium hydroxide etches silicon quickly and at a stable rate which relies on the concentration of the solution and the temperature of the liquid. Aside from that, this etching process is also influenced by the crystal planes of the silicon and the doping concentration. These factors can be applied for direct etching in certain directions and stop etching at defined points. The result is that KOH etching can produce the accurate nanostructures required if the crystal planes and the doping are used accurately.

Modutek, a company with over 30 years of experience providing semiconductor equipment solutions, offers Teflon tanks that are specifically designed to support the KOH etching process, which ensures high-quality wafer fabrication.

Teflon tanks are used because aside from its stability, they have the ability to eliminate contamination from the tanks or fluid paths by making sure that the KOH solution only comes in contact with Teflon. Teflon is not affected by the corrosive chemical. In addition Modutek’s Teflon tanks are welded using advanced PFA sheet welding techniques, which guarantees reduction of contaminants.

The complete article “Why Teflon Tanks Are Used with the KOH Etching Process” explains more about the necessity of using Teflon tanks when doing KOK etching. If you have questions or would like a free consultation or quote on equipment to support the KOH etching process, please call 866-803-1533 or send an email to modutek@modutek.com. 

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.