Bev,
J-STD-020, section 1.1 states in part: "This classification procedure
applies to all nonhermetic solid state Surface Mount Devices (SMDs) in
packages, which, because of absorbed moisture, could be sensitive to
damage during solder reflow."
But you make a good point... It would be great to have a similar
classification for PCBs so that, instead of telling the end user what
temps and conditions the raw materials are designed to meet, the end
user would know what to expect of and how the pcb fab *will* perform
during assembly, storage, and use conditions.
("It warped during Pb-free reflow? We used 170degC Tg material; it
shouldn't have done that... You have to ship the boards today you say?
Your *** is grass and your customer is the lawnmower? Sorry to hear
that...")
Regards,
Roger
-----Original Message-----
From: Bev Christian [mailto:[log in to unmask]]
Sent: Wednesday, May 11, 2005 9:59 AM
To: TechNet E-Mail Forum; Roger Stoops
Subject: RE: [TN] MSL?
Roger,
I am wondering if we can make your last statement so definitive. During
the early 90's boards were not made as well as they are now and we did
have to bake them - from certain manufacturers. I am wondering with the
higher temperatures for Pb-free soldering if we might see the problem
raise its ugly head for some of the lower end suppliers. I don't know,
I'm just asking.
Bev
RIM
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Roger Stoops
Sent: May 11, 2005 9:52 AM
To: [log in to unmask]
Subject: Re: [TN] MSL?
MSL = Moisture Sensitivity Level, defines and characterizes how an
IC/xstr/dio/etc. package will withstand exposure to temperature and
humidity over time. Specifically important for defining what process or
procedure to use in assembling semiconductors to a pcb. The MSL level
has become more of an issue with RoHS due to the elevated reflow temps.
J-STD-020 describes this in more detail; the lower the number, the more
robust the part. The Jedec std is free on the 'net.
Doesn't really pertain to PCBs.
Regards,
Roger
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Eddie Rocha
Sent: Tuesday, May 10, 2005 6:23 PM
To: [log in to unmask]
Subject: [TN] MSL?
I'm a PCB fabricator, and I have a survey asking me several general
questions related to RoHS with one being moisture sensitivity level
(MSL)? What exactly are they looking for? Does this pertain to bare
PCB's?
-- Thanks,
Eddie Rocha
South Bay Circuits
(480) 940-3125 x122
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