Suixin Zhang wrote:-
>Hello,
>I have heard that sometimes there can be a compatibility issue 
>between solder mask and solder paste used. Please forgive my 
>ignorance. I am wondering what the problem can be if they are not 
>compatible and how to test the compatibility.
>Can anybody shed some light on it?

I do not know of any compatability issue beteen solder paste and solder
mask. If you are producing solder balls in the infra red oven you need
to look at the paste and your infra-red oven profile. If this is your
problem, then a matte solder mask is easier to clean but you should
concentrate on trying to eliminate solder ball formation.

However, the compatability between solder mask and wave solder flux is
important. Solder balls formed in the wave due to gassing of the flux
adhere to the solder mask. The right flux/solder mask combination can
dramatically reduce the incidence of solder balls.

The surface of the solder mask should ideally be matte finish to reduce
the adhesion of solder balls. A low solids flux is better as it is the
flux residues which stick the solder balls to the surface.

Wave solder machine suppliers are one source of data on different mask
and flux combinations.

Good Luck,
Paul Gould
Teknacron Circuits Ltd
[log in to unmask]
Isle of Wight,UK

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************