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Solder mask thickness measurement

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#75938

Solder mask thickness measurement | 6 July, 2016

Dear members,

Recently we have found that solder mask thickness variation could lead to solder balling under QFN packages for a high reliability device.

Is there any industry proven method for solder mask thickness checking? Any equipment or any measurement method?

Which IPC standards describe requirements to solder mask thickness?

Any input is higly appreciated. Thank you in advance.

Regards, Pavel

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#75941

Solder mask thickness measurement | 6 July, 2016

Hi Pavel

IPC-6012 - Qualification and Performance Specification for Rigid Printed Boards, Paragraph: Solder Resist (Solder Mask) Requirements, Sub-paragraph: Solder Resist Thickness has words to the effect …

* Solder mask thickness shall be according to the procurement spec, otherwise it is not measured.

* Either instrumental methods or a microsection of the parallel conductors on the E coupon are acceptable methods for measuring thickness.

Some ppl see solder balling under BTC when they apply too much solder paste.

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#75942

Solder mask thickness measurement | 6 July, 2016

Hi Dave,

Thank you for the input. We have completely checked the whole process and solder mask thickness is the only thing that might impact.

I wonder whether you might know chemical solutions capable to dissolve solder mask?

Regards, Pavel

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#75943

Solder mask thickness measurement | 6 July, 2016

Hi Pavel here in Poland interflux sells a product C8 who can remowe the solder mask, no disolve. It is a high alcalin product with other stuff, you can ask to vsd@interflux.pl

jean vadim

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#75948

Solder mask thickness measurement | 6 July, 2016

Circuit Technology Center “4 Techniques for Removing Solder Mask” [http://www.circuitrework.com/features/607.shtml]

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