Carrie: First I am assuming your are asking about LPI soldermask only.
From a board fabrication standpoint there should not be any additional cost
or processing steps. The major difference is in the formulation. So asking
or specifying a matte mask should not effect the bare board cost.
A full matte finish may be more susceptible to scratching depending on the
filler system and amount of resin in the mask. It is also more prone to
showing surface cosmetics and white haze/residue. Gloss finish boards do not
display this as much. However gloss soldermask can be hard to inspect, TU
and manually load components due to it's high reflectivity.
There is another issue and that is the electrical performance properties of
the mask. There are "some" matte masks that have reduced electrical
properties than a gloss mask. This can be the result of higher filler
content, less resin, etc. However there are many more things that play into
this than just the matte issue. The formulation, type and amount of resins
and cure can also influence the electrical performance greatly. There are
many matte masks that are comparable to non-matte types.
Most people specify a semi-matte/semi-gloss as opposed to a full matte. This
provides a good compromise from the two ends of the spectrum.
Regards
Michael Barmuta
Staff Engineer
Fluke Corp.
Everett WA
425-446-6076
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Morse, Carrie
Sent: Tuesday, January 27, 2004 8:24 AM
To: [log in to unmask]
Subject: [TN] Matte vs. Gloss Finish for Solder Mask
We are a CM and find that boards with a Matte finish are less susceptible to
solder balls at our wave processes. We have discussed this with our flux
suppliers and equipment suppliers and have read a few articles on why solder
balls are more likely to form on the gloss finish boards. We have received
many recommendations on how to reduce or eliminate the solder balls (change
flux volume, change preheat, change this, change that) -- But, the one theme
from a root cause standpoint that recurs is the mask.
What are the pro's and Cons of a Matte vs. Gloss finish for solder mask?
Is one easier to apply, less expensive?
Why would one be specified or used vs. the other?
What is the specification for Gloss? Normally I see "Solder mask per SM-840
Class T". Is finish an option from a fab standpoint when it is not
specified?
Ultimately I'd like to be able to specify Matte Finish to the supplier, but,
I do not know how this may affect longevity of the board, cost, or even
perception of quality. I've heard some say that the end customers like the
way that the gloss boards look -- "shinier looks cleaner"?
Any and all info including personal opinions about matte vs. gloss finish
are welcome.
Thanks,
Carrie
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------
|
