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Cleaning procedure when WS609 flux is used

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#53261

Cleaning procedure when WS609 flux is used | 18 January, 2008

Is normal DI rinse cycle enough to wash away all residue after SMT assembly of high density substrate?

This substrate would later be over molded to form MCM module package and I am seeing delamination in high density areas of the substrate at MSL3 testing.

I appreciate any inputs you may have in this regard.

thanks in advance, Arun

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#53274

Cleaning procedure when WS609 flux is used | 21 January, 2008

Just what is delaminationg during testing?

Water washing should be sufficient to clean WS609. On the other hand, it's possible you're conveyor speed is too high to do a good job cleaning the high density areas. What kind of testing have you done to assess the cleanliness of these areas?

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#53283

Cleaning procedure when WS609 flux is used | 21 January, 2008

We see delamination at Mold compound to substrate interface when tested for MSL3. We haven't tested the substrate for cleanliness. Can you please suggest methods for this?

thanks, arun

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#53289

Cleaning procedure when WS609 flux is used | 21 January, 2008

In your situation, the issue is the compatibility of your flux residues and the encapsulant that you choose. First, contact your encapsulant supplier for advice. They've likely been down this road with other customers and may be able so save you some money. Then, consider involving your encapsulant supplier and a failure analysis laboratory in: * Assessing the contamination level on your product. * Determining practical go / no go limits from ion chromatography analysis and possibly surface insulation resistance. * Instituting effective process control methods for your assembly troops.

Laboratories to consider are: * Trace Laboratories 1150 W. Euclid Ave Palatine, IL 0067-7397 847-934-5300 Fax 4600 http://www.tracelabs.com info@tracelabs.com Jeffry Schutt * Robisan Laboratory 6502 East 21st St Indianapolis, IN 46219 317-353-6249 fax 317-917-2379 http://www.robisan.com mail@robisan.com Susan Mansilla * Foresite, Inc. [Contamination Studies Laboratories] 1982 S. Elizabeth St. Kokomo, IN 46902 (765) 457-8095 Terry Munson * ACI/EMPF One International Plaza Suite 600 Philadelphia, PA 19113 610-362-1200 Fax: 1290 Guy Ramsey gramsey@aciusa.org x 107

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#53422

Cleaning procedure when WS609 flux is used | 29 January, 2008

Dave F....BOGUS BOGUS BOGUS What compatability issue could there possibly be if the flux is removed during wash???? Why on EARTH would you leave ANY WS flux residue on the board? A recipie for disaster! Beef up the cleaning process, test for contamination, beef it up again if required. Ionic contamination testing is readilly available.

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#53436

Cleaning procedure when WS609 flux is used | 29 January, 2008

Bruce Barton:

We're not intending to suggest that anyone is purposely leaving WS flux residue on the board after cleaning. Fact is, Arun isn't sure if the boards are completely clean. Arun said, "We haven't tested the substrate for cleanliness."

Given that the mold is delaminating in the areas with close component spacing, it's possible the boards are not being cleaned well in that area. We suggested a method to determine if the boards were clean and how operators could monitor cleanliness on an on-going basis. What's bogus about that suggestion?

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#53539

Cleaning procedure when WS609 flux is used | 3 February, 2008

Won't argure with you Davef, but guys who suggest totally unnecessary steps to resolve a cleaning problem drive me NUTS!! What would the moulding compound manufacturer have to do with it? HIS BOARD IS NOT CLEAN!! Keep it simple, get the job done! Don't fall into paralysis by analysis...you'll never ship anything!!

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#53542

Cleaning procedure when WS609 flux is used | 4 February, 2008

Bruce: We know Arun is not cleaning the board properly. Arun does not know how to determine if the board is clean. Arun doesn't know how long to clean the board. Apparently, you do. Tell Arun the answers.

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