Hi Helena,
The "stub" is a requirement for electroplated gold edge fingers; so it
is accepted when it remains. Indeed, it is not realistic to completely
remove the stub without likewise touching the finger where the stub and
finger meet.
In other words, if a router bit is used to cut the laminate close enough
to cut off the stub, the router bit will also nick the tips of the
finger. Or if a post plating "stub etch" process is used and it is
attempted to completely remove the stub, film alignment and etch
tolerances will also cause part of the finger to get etched in some
locations.
If you are familiar with seeing gold edge fingers without the "stub", it
is because those fingers used immersion gold; which does not require the
stub. But it also does not have very thick gold on the contact.
Thanks,
Ryan Grant
Memory Modules SQE
Micron Technology Inc.
(208) 363-3683
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pasquito, Helena
Sent: Wednesday, February 27, 2008 1:24 PM
To: [log in to unmask]
Subject: [TN] Gold Plating Question
Hello Technetters,
Question for clarification on IPC Class 3 requirement with regards to
Hard Gold Plating on Edge Fingers:
Which IPC specification states the "stub" remaining on a gold edge
finger, (example see photo in IPC-A-610D, Figure 10-1) is allowable?
Or, is there a spec in IPC that says that it's NOT acceptable.
Thank you!
Helena Pasquito
Manufacturing Skills Instructor
M/A-COM, Tyco Electronics
1011 Pawtucket Blvd., M/S 107
Lowell, MA 01853
978-442-5024
[log in to unmask] <mailto:[log in to unmask]>
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