Now Joe, if you really wanted me to think like a lawyer I would argue as
follows:

Example 1 Mask at pad periphery

Not normal since boards need a clearance on the mask to avoid mask on
the pads.

Example 2 Mask opened up to give a tolerance to the pad

Which is normal, and will give a smaller or larger "keyhole effect"
depending on the clearance to the pad.

The above example has been in existence for ever, and if they ever go
get the Ark from up on mount Ararat, they will probably find this mask
clearance in the boards on the GPS system............8-)

So maybe we are not talking pad design at all here, maybe we are talking
solder mask window opening.

John


John Burke
Senior Manager - Operations , Optichron
[log in to unmask]
W: 510 249 5233
M: 408 515 4992
http://www.optichron.com
Profile: https://www.linkedin.com/e/fps/2665502/

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Joe Fjelstad
Sent: Monday, April 24, 2006 9:09 AM
To: [log in to unmask]
Subject: Re: [TN] BGA and CGA pad questions.

In a message dated 4/24/2006 9:00:04 AM Pacific Daylight Time,
[log in to unmask] writes:

Very  interesting.

Does that mean that patent cover the solder mask open  window and trace
width?. If you simply change nothing on your design, but  open up a slot
in the solder mask on the trace side of the pad you will get  a
"keyhole"
effect in the final soldered joint  automatically.


John

John Burke
Senior Manager -  Operations , Optichron
[log in to unmask]
W: 510 249 5233
M:  408 515 4992
http://www.optichron.com
Profile:  https://www.linkedin.com/e/fps/2665502/




Hi John,

Thinking like a lawyer are you?... RoHS is having that effect on a lot
of
good engineers lately... ;-)

Actually I would argue that you are probably right but would need to
make
certain by reading the claims which could as a counter point might  have
a claim
to equivalence, something which could possibly be construed  from a well
crafted claim. Therein lies the art...

Best,
Joe


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