Hi Bill,
We routinely solder dip the CQ132 for Actel.  When we handle them they
still have their non-conductive tie-bars on them.  It is a lot easier to
trim the units first then solder dip the leads.  If you don't have too
many you can use the RMA flux and hand dip the components just fine.  Be
sure to keep the ceramic body out of the solder.  Since you don't have
preheat you don't want to create a significant differential temperature
across the component body.  You may want your operators to practice with
some cheap plastic components first.  Depending upon whether the units
have been burned-in you may see some problems (pin holes and dewetting)
at the location of the electrical contact.  This can be resolved by
using a stronger flux.  We have a flux specifially formulated for
tinning fine pitch components if you need a free sample just give us a
call.

Because of the gold thickness it is usually recommended that you do a
double dip (especially since you have little control of depth and time)
and I assume your pot is static.  The trick in getting things just right
is to lift one end out of the solder first.  In other words the solder
should break free from pin 1 then pin 2 ... etc.   About a 3 degree
angle should do the trick.  You will need a pretty steady hand for this
job.  Also, you will want to exit the solder relatively quickly to keep
the thickness above the typical minimum requirement of 200 microinches
(if this applies to you).

The solder temperature we use is 250 C.  And just for the record our
machines are automatic and we don't solder dip any components manually.
Our experience has taught us that processes manage to change themselves
whenever you don't password protect them.

One final word of caution.  Every once in a while a gross leak escapee
gets into the mix.  This is a part that is filled with fluorocarbon
liquid that will pop when it gets hot enough.  It can scare the pants
off of your operators and can splash the solder around so be certain
they are wearing the proper safety gear.

If you need any further assistance please feel free to contact me
directly at (408) 526-1350 x 1.

Regards, Russ Winslow

Six Sigma
1940 Concourse Drive
San Jose, CA  95131

[log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Kasprzak, Bill (esd)
US
Sent: Tuesday, March 09, 1999 9:45 AM
To: [log in to unmask]
Subject: [TN] : How to Tin Actel-CQ132


Fellow techies:

We are going to be using an Actel CQ132 Ceramic Quad Flatpack (25 mil
pitch). From a process standpoint I have ordered a die from Fancort to
form
the part, and we will be dispensing solder paste through a Camalot
Poisitve
Displacement pump (can't stencil due to component location), component
will
be placed then run through my Heller 1088 reflow system. All this
forming
and dispensing stuff is new to me but the pitch and the reflow is not.

There is one part of the process that I'm taking for granted and that is
the
tinning of the part. The part is received with gold leads.(Doesn't come
in
anything but gold, and besides, the part will not form well with solder
on
the leads)  I'm assuming that after the part is formed, I can dip the
feet
of the formed part in RMA flux then tin in a 500 degree F solder pot
like
any other part, one side at a time. I would then clean the part in
Flux-Off-CZ then place into my matrix tray to hold until placement time.
I'll probably use a vacuum pencil to hold the part.

Is the tinning of this part as routine as I think its going to be or do
I
need to worry about another new process ?  Recommendations are needed.

Bill Kasprzak
Moog Inc.

(Have we hit the 2000 mark yet ? [Just havin' fun Steve, I know how it
feels])

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