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Date: | Tue, 24 Jan 2006 08:54:46 -0500 |
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Gloss mask
- will increase the propensity for solderballs in assembly
- may have issues with conformal coat wetting
- may have issues is resolving covered fiducials due to high reflection
- material tends to hide defects/conditions on the PCB surface
- Gloss mask does offer a cleaner surface since the profile is lower
Matte mask
- prevents solderballs as surface tension is low
- has good wetting/adhesion for confomal coating
- has good resolution for fiducial recognition - low reflection
- shows PCB surface conditions readily
- is more difficult to clean, ionics are high - although I think looks
better with no-clean
We lean to a mask that is middle of the road in light absorption - ~
45-55%. This seems to satisfy the spectrum of needs in fab and by our
users.
Jeffrey Bush
Director, Quality Assurance and Technical Support
VERMONT CIRCUITS INCORPORATED
76 Technology Drive - POB 1890
Brattleboro, Vermont 05302
Voice - 802.257.4571 ext 37
Fax - 802.257.0011
<http://www.vtcircuits.com/>
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Chris Ball
Sent: Monday, January 23, 2006 1:03 PM
To: [log in to unmask]
Subject: [TN] LPI - matte vs. gloss or semi-gloss
Hello All-
For many years we have specified matte finish LPI soldermask. Have a
supplier asking us to switch to gloss or semi-gloss to avoid 'solder
smear'
issues.
Any input as to the pros and cons of each would be appreciated.
I think I remember issues finding fiducials with glossy mask but I might
just be making that up, and all the equipment has changed since then
anyway.....
Thanks in advance,
-Chris
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