Found solder bridging under SMT Chip of Wave process

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Dear all friend, I found problem of soldering bridging betw... - May 23, 2000 by Wirat S.

Hello, I think the problem can be: 1.�- some humidity in th... - May 23, 2000 by �ngelo Marques

Wirat S.

#4025

Found solder bridging under SMT Chip of Wave process | 23 May, 2000

Dear all friend, I found problem of soldering bridging between SMT Chip terminal & Glue , but under the chip body. My process was double side SMT assembly with bottom side adhesive & heat curing, then wave soldering with water soluble flux (OS type) At ICT found major reject criteria was short nail. I did reconfirm short nail was and small solder bridginh in between epoxy & chip terminal by x-ray and remove the chip. Then I did check with curing profile, was proper cured @ 150 degree C, 1:52 minute. Any body had experience with this type of problem , please help me. Give me understanding, what happen and how to solve this type of problem. My assembly was very simple PCB FR4, double side with 0805 chip. Thank you, Wirat S.

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�ngelo Marques

#4026

Re: Found solder bridging under SMT Chip of Wave process | 23 May, 2000

Hello, I think the problem can be: 1.�- some humidity in the adhesive, 2.�- some bubble of air in the adhesive when you cured the adhesive some humidity will go evaporate and when you make the soldering the same soldering will make a bridge between the terminal`s of the chip, because the humidity make a big hole in the adhesive. It`s the similar for bubbles in the adhesive. if you need more help, just send an e-mail.

A. Marques

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