We handle low/medium volume with inboards Ni/Au contacts in vertical HASL.
We have now problem with the peelable solderesist from Peters (SD2950).
If there is Pb/Sn-particles on the contacts due to the high pressure, maybe you could improve the adhesion of the resist.
Have you tried with increased thermal cure or mild acid rinse before screenprinting?

Best regards

Jan Thuesen



-----Oprindelig meddelelse-----
Fra:    Rob van Pol - Senior Account Engineer [SMTP:[log in to unmask]]
Sendt:   22. oktober 1997 10.35
Til:    [log in to unmask]
Emne:   [TECHNET] Inboard Ni/Au contacts

Fellow Technetters,

At present we use a screenable laquer from Lackwerke Peters
(Werner Peters SD 2955) to cover inboard Ni/Au (hardgold)
contacts/connectors during horizontal hot air levelling.

In a few months however we are not allowed to use the fluid to strip
this laquer anymore, due to enviromental reasons.

We have tried peelable solderresists but these are not 100 %
resistant to the pressure during horizontal hot air levelling resulting
in P/Sn particles on the Ni/Au contacts.

Manual taping is also no option volumewise.

# Which materials/processes are available for manufacturers which
   use horizintal HASL to cover, in medium/high volume, inboard
   Ni/Au contacts before HASL?

Any thoughts on the subject or any other alternatives would be
appreciated.

Thanks,


Rob van Pol
MOMMERS PRINT SERVICE B.V.

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