How Specialized Wet Bench Equipment Improves the RCA Clean Process

The RCA clean process removes contaminants from silicon wafer surfaces with so that additional wet process semiconductor manufacturing steps can occur. Specialized equipment incorporated in wet benches ensures that contaminant and particle removal is complete and silicon surfaces are clean for the next process steps.

The RCA process consists of two steps:

1) RCA Clean SC1 Step Removes Most Wafer Surface Contamination

This cleaning step uses chemicals to dissolve impurities while leaving the underlying silicon surface unaffected. The wafers are placed in a solution containing equal parts of ammonium hydroxide and hydrogen peroxide in five parts of de-ionized (DI) water. The solution is brought to 75 degrees Centigrade, and the wafers are placed in the solution for 10 to 15 minutes. Organic impurities are dissolved, and particles are removed, but a thin layer of silicon oxide forms on the wafer, and there is some contamination with metallic ions and particles.

2) RCA Clean SC2 Removes Impurities

This cleaning step removes metallic impurities. The newly cleaned wafers are placed in a bath containing equal parts of hydrochloric acid and hydrogen peroxide in five parts of DI water. The exact ration may vary depending on the application. The bath is heated to around 75 degrees Centigrade with the wafers soaking for about 10 minutes. Alkali residues, metal hydroxides, and other metallic particles are now removed, leaving the wafers completely clean and free from all kinds of particles.

Wafer cleaning equipment has to meet specialized functions. Specialized equipment is required to carry the RCA process steps effectively. The chemicals required have to be in the right quantities, and then when they're no longer needed, they need to be neutralized and disposed of safely. The concentration of chemicals is also critical, as well as the bath temperature and the timing to achieve the desired cleaning results. Contaminants and particles have to be rinsed off and filtered out. Key characteristics of effective cleaning include a low particle count on the wafer's surface and a resulting low rejection rate for fabricated wafers.

With 40 years of experience as a semiconductor equipment manufacturer Modutek has the experience, to provide the equipment you need for the RCA clean process as well as other semiconductor manufacturing applications.

For more details read the complete article “How Specialized Wet Bench Equipment Improves the RCA Clean Process”. If you would like to discuss your specific needs contact Modutek by calling 866-803-1533 or email Modutek@Modutek.com.