Specific Process Knowledge/Wafer cleaning/Cleaning with Soap Sonic

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Cleaning of samples that have been out of the cleanroom

Soap sonic clean placed in the wash bench in the changing room (gowning).

The soap sonic is done in a tank with ultrasonics placed in the cleaning bench in the changing room. The cleaning solution is DI water to which a little diluted Triton X-100 is added. Triton X-100 is a nonionic detergent which is free of alkalies. This detergent is added to reduce surface tension and thus help removing particles from the samples to be cleaned.

It is used for samples (typical wafers or chips) that have been out of the cleanroom e.g. if they have been diced, and you want to bring them in again for measurement or further processing. In most cases the Triton X-100 sonic clean is not enough. The samples will also have to be cleaned in a piranha solution. If your samples cannot withstand piranha then you must ask DTU Danchip for special permission to bring in your samples without the piranha.

Procedure

• Fill tank with DI water (enough to completely cover your samples)
• Add 20 - 30 drops of diluted Triton X-100 detergent (From the rinse/spray bottle. Do NOT use undiluted Triton X-100)
• Start ultrasonics using the front panel button
• Leave sample in ultrasonics for 10 min
• Switch off ultrasonics
• Fill rinse bath with DI water and rinse samples
• Remove samples and dry them
• Dump Triton X-100 and the rinse water baths to drain. Rinse tanks with DI water. Leave dump valve open so the bath drains completely
• Continue with piranha.