Ultrasonic Cleaning Causing Damage

Mr. Schreiber developed the original ultrasonic stencil cleaning process in 1989. Obtained the only EPA Verification for specific parameters of Environmental Safety, User Safety and Cleaning Efficiency for a stencil cleaning process.

Mr. Forsythe is a recognized expert in cleaning chemistries and processes. Tom has a Bachelor's in Applied Mathematics & Engineering from the US Naval Academy. He is well published in both the industry trade magazines. Tom has spent the last 14 years with Kyzen Corporation.

Mr. Tosun has published numerous technical articles. As an active member of the SMTA and IPC organizations, Mr. Tosun has presented a variety of papers and studies on topics such as "Lead-Free Cleaning" and "Climatic Reliability".

Rodney is currently Operations manager at SCS coatings, Global Leader in Parylene and Liquid Coating equipment. Rodney applies his BS in Computer Integrated Manufacturing from Purdue University, along with 20+ years of Electronic manufacturing and Equipment Assembly, to direct the Equipment business at SCS Coatings. "We provide unique, value added coating equipment solutions for our customers". Including conformal, spin and Parylene coating expertise.

Mr. Munson, President and Founder of Foresite, has extensive electronics industry experience applying Ion Chromatography analytical techniques to a wide spectrum of manufacturing applications.

Mr. Konrad has been in the electronic assembly equipment industry since 1985. He is founder and CEO of Aqueous Technologies Corporation, a manufacturer of automatic de-fluxing equipment, chemicals, and cleanliness testing systems.

This is an old problem. The wire bonds inside the package if gold, can transmit the ultrasonic energy and when a node is on the wire it will neck down and become a latent failure or become a catastrophic failure that is detected right away. This is what happens when the PWB the microcircuit is attached to is in contact with the ultrasonic cleaner sides or the basket holding the PWB. It was originally discovered by General Dynamics and a government alert was posted to stop defense contractors from doing this. Use of a sweep frequency ultrasonic bath seemed to mitigate this but the jury was out on it. The Ultrasonic equipment manufacturers did not like this discovery. My advice is don't use ultrasonic cleaning with microcircuits on PWBs unless you are sure the cleaning does not affect the thin gold wires used inside the microcircuit are still 100% okay. They could be necked down and over heating and waiting to fail in the field.

Damage to cavity packages with crystals or wire bonds is a thing of the past. It was well proven by our GEC Research project. I have cleaned cavity parts as a demonstration with the lids removed with no damage under normal conditions. SMART Sonics website feature our old GEC papers and reports on the testing conducted at the time. On the other part of the topic the key thing is to get you chemistry and flux residues and make sure they are soluble. Then test you cleaner to see its capability to clean at the stand off heights you require. This is even before you move to contamination testing or SIR. Simple tests in manufacture to loo at capability are key. Finely don't forget that most sites have been no clean for so many years engineers often have never evaluated components parts for cleaning compatibility which should be confirmed on a product BOM.