Letter 20006

Aluminum corrosion by DI water [Arizona] 

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Have recently encountered problems regarding aluminum bond pads (in a chip), being eaten up by just pure dipping for 30 minutes to 1 hour in just pure DI water. Didn't think pure water can erode or etch. Anybody has explanation or answer?

Thanks,

Aubert Escio
- Chandler, AZ

DI water, becasue of the high free Hydrogen ion concentration is VERY corrosive. DI water is so corrosive it cannot be used in iron pipes, and will certainly tear into aluminum. Try distilled water.

Robert H Probert Robert H Probert Technical Services Garner, NC, USA Editor's note:        Mr. Probert is the    author of Aluminum How-To

I hope you have found an answer to your problem, since it has been over a year. But I was reading and I have the answer. Your problem is a very common phenomenon in the semiconductor industry. Eventhough they use DI water in their process they have to inject CO2 to bring the resistivity of water down. This way the DI water is not corrosive and will not harm your metalization. This problem of metal etch will cause reliability problem for the device and potentially bonding problems.

Hope this helps.

Eric Prinz
- Morgan Hill, CA

I am looking for topics on corrosion of aluminum copper leads with TiN in DI water. This is a problem during the water rinse after solvent clean. In fact I am looking for information of this affect with pH of DI water.

Allen Page
Semiconductor - Richardson, TX, USA

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