Wafer cleaning

To remove or thin any kind of oxide in the FEOL a DHF step is performed. With Inline spiking technology DHF ratios from 0.006% to 0.15% are possible (with spiked 49%HF).

The sustainable alternative for organic residue clean from the wafer surface consists of Ammonia, Ozone and DI Water. The DI – ammonia mix vary from 50:1 to 1000:1. That means very small amounts of Ammonia are spiked into the DI water stream. Additional, to the DI Water – Ammonia mix injected from one side of the process chamber, Ozone in gasform is injected from the other side. With this all its effectivity is enhanced directly on the wafer surface.

Almost like the organic removal the clean of metallic residues works. The mix to clean metallic resiudes from the wafer surface consists of Hydrocloric Acid (HCl), Ozone and DI Water. The DI Water – HCl mix vary from 300:1 to 1000:1. That means very small amount of HCl are spiked into the DI water stream. Additional, to the DI Water – HCl mix injected from one side of the process chamber, Ozone in  gasform is injected from the other side. If no contamination of noble metals is expected Ozone is not needed.