Victor
1) TCE is compatable with the board and bga. Not sure why that would influence an answer concerning voids...
2) main purpose is to provide support to solder joints (vibration resistance).
3) I "hope" to fill the entire gap (100% fill) - but realistically some voids are likely to occur. What % of voids are reasonable and acceptable is the question.
4&5) Loctite 3568 is applied to 2 sides of the component in accordance with the manufacturer's instructions, the board and part are preheated to 100C and following application the cure is 15 minutes at 150C.
regards,
Graham Collins
Process Engineer,
Northrop Grumman Canada
Atlantic Facility
(902) 873-2000 ext 6215
>>> [log in to unmask] 09/10/02 10:17AM >>>
Graham,
Have you considered the thermal properties, TCE, of the Locite 3568
product.
Is this compatible with the TCE of the PCB and device carrier.
What is the main PURPOSE of the proposed UNDER FILL application?
How far into the device carrier to you HOPE to FILL?
Will the LOCITE have to be cured?
Is the PCB Pre Heated?
Victor,
-----Original Message-----
From: Graham Collins [mailto:[log in to unmask]]
Sent: Tuesday, September 10, 2002 6:09 AM
To: [log in to unmask]
Subject: [TN] BGA Underfill
Good day TechNet!
A question for the BGA / Underfill guru's out there (hopefully we have some
of those online).
Using a capillary flow underfill on a BGA, say a .050 pitch 26x26 array,
what is a reasonable result to expect with respect to voiding? Should this
process result in no voids, some voids, lots of voids? Given the size of
this part (1.38" square), is it reasonable to expect a void free underfill?
The particulars: I'm using Loctite 3568 underfill, applied using a syringe
along two edges (L pattern). Product is on a hotplate at 100C.
Thanks all!
regards
Graham Collins
Process Engineer,
Northrop Grumman
Atlantic Facility of Litton Systems Canada
(902) 873-2000 ext 6215
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