FYI,
Our standard package for our optical sensors is 36 LCC. The silicon sits
inside a cavity sealed with a glass lid and the die is wire bonded. We
sold about 10 million of them last year a few less the year before and
few less the year before that.
We've never heard of sensors failing due to damage from ultrasonic
cleaning. Certainly in house, we ultrasonically clean sensors as a
matter of course and again, we've never seen a failure.
I imagine a problem might occur if a bond wire had a resonant frequency
near the frequency of the tank. However we've never heard of this
happening...
[log in to unmask] wrote:
> Mel,Unfortunately, much of this can not be shared.Suffice it to say,
> however, that it is my strong recommendation that any package (TO or
> MCM), having an internal cavity, where the wires are not surrounded by
> any dampening medium other than a gas (nitrogen) should NOT be
> subjected to ultrasonic cleaning - official reports, or not!One fairly
> quick way to test for damage is a before and after wire pull -
> naturally this is destructive.
> Steve Creswick - Gentex CorpPS - I heard on the news last night that
> parts of Alabama received 0.5-1" of snow, and a bit of freezing rain.
> Our official total was something like 54" Nothing like Buffalo, NY!
>
> -----Original Message-----
> From: Mel Parrish [mailto:[log in to unmask]]
> Sent: Wednesday, January 02, 2002 4:10 PM
> To: [log in to unmask]
> Subject: Re: [TN] Ultrasonic Cleaning
>
> Steven and allI agree with your discussion but I have not
> seen supporting test results other than the studies from the
> Lake years ago with the TO package types. If you have any
> information that we could put in front of the J-STD-001, 610
> or other committees to support content, I would greatly
> appreciate it. The snow hasn't reached us in AL yet, but I
> wish you would take back this cold weather. Mel Parrish
> Soldering Technology International
> Madison, AL
> 256 705 5530
> 256 705 5538 Fax
> [log in to unmask]
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of
> Creswick, Steven
> Sent: Wednesday, January 02, 2002 9:52 AM
> To: [log in to unmask]
> Subject: Re: [TN] Ultrasonic Cleaning
>
> Mel,I agree with the TO packages of old, but I
> have built many large scale hybrids (nowadays
> called MCM's) for both Military and
> pseudo-Military applications that contain anywhere
> from a few hundred to almost 1000 wire bonds.
> These are hermetic packages, usually ceramic, or
> metal. I suggest that no one ultrasonically clean
> them - Sorry, no return for defective
> components!!Also, the fine wire aluminum wedge
> bonded parts are more sussecptical to ultrasonic
> damage than the gold ball bonded units. The wedge
> bonded wires will fail (quicker) at either of the
> two 'heels'.Finally, don't go ultrasonically
> cleaning your ceramic Pentium processors, or many
> of the ceramic column grid array packages
> discussed last year.3-4 ft deep here in Michigan.
> Steve
>
> -----Original Message-----
> From: Mel Parrish
> [mailto:[log in to unmask]]
> Sent: Wednesday, January 02, 2002 2:24
> PM
> To: [log in to unmask]
> Subject: Re: [TN] Ultrasonic Cleaning
>
> StevenThe specific component types that
> were concerns for this cleaning method
> per the DoD studies were TO package IC's
> (not used much these days). Later
> testing by the EMPF looked at
> encapsulated components with better
> results, should still be available for
> review but I don't believe that the DoD
> studies are. Mel Parrish
>
> -----Original Message-----
> From: TechNet
> [mailto:[log in to unmask]]On
> Behalf Of Creswick, Steven
> Sent: Wednesday, January 02,
> 2002 8:17 AM
> To: [log in to unmask]
> Subject: Re: [TN] Ultrasonic
> Cleaning
>
> From a hybrid manufacturing
> standpoint we found that if
> the wirebonds are surrounded
> by the ultrasonic cleaning
> fluid there is no
> problem.However, if there is a
> cavity - there will be a
> problem.Put another way -
> ultrasonic cleaning of sealed
> units (nothing but dry
> nitrogen around the wires) was
> an open invitation for
> non-functional units.
> Cleaning of un-sealed units
> was not a problem.Most plastic
> encapsulated devices have no
> (intentional) air pockets
> around the wires, therefore, I
> would expect them to be okay.
> If you have sealed metal can
> type packages I would stay
> away from the
> ultrasonics.Steven Creswick -
> Gentex Corporation
>
> -----Original
> Message-----
> From: Dieselberg,
> Ron
> [mailto:[log in to unmask]]
>
> Sent: Wednesday,
> January 02, 2002
> 10:26 AM
> To: [log in to unmask]
> Subject: Re: [TN]
> Ultrasonic Cleaning
>
> I had only one
> experience, about 15
> years ago. The
> assembly tested OK
> before cleaning in
> an ultrasonic tank.
> Afterwards it did
> not work. Failure
> analysis folks said
> almost all of the
> wire bonds in the
> three transistors
> were damaged.. Maybe
> someone has had good
> luck, but not me.
> That was the first
> and last on anything
> but a component-less
> board!
>
> Ron Dieselberg
> Trainer/Auditor
> CMC ELECTRONICS
> CINCINNATI
>
> [log in to unmask]
>
> -----Original
> Message-----
>
> From:
> Vinit
> Verma
> [mailto:[log in to unmask]]
>
> Sent:
> Thursday,
> December
> 27, 2001
> 5:48 AM
> To:
> [log in to unmask]
>
> Subject:
> [TN]
> Ultrasonic
> Cleaning
>
> Hi
> Technetters,
>
> I am
> presently
> evaluating
> post
> reflow PCB
> cleaning
> machines,
> both
> aqueous
> and
> ultrasonic.
> I have a
> concern
> regarding
> ultrasonic
> cleaning.
> Read
> somewhere
> that the
> ultrasonic
> frequencies
> can have
> an effect
> on the
> wire
> bonds
> inside the
> packaging.
> Does
> anyone
> have any
> idea of
> this?
>
> Thanks in
> anticipation.
>
> Regards
> Vinit
> Verma
>
>
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>
--
Eric Christison
Mechanical Engineer
STMicroelectronics
33 Pinkhill
Edinburgh
EH12 7BF
Tel: (0)131 336 6165
Fax: (0)131 336 6001
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