 
| Subject: | |
| From: | |
| Reply To: | TechNet E-Mail Forum. |
| Date: | Tue, 26 Aug 2003 08:10:27 +0300 |
| Content-Type: | text/plain |
| Parts/Attachments: |
|
|
David,
Pressing down the BGA component is an action to find open circuit in BGA
solder joints or die bonding open inside the component.
The reason for the opens can be pads size, solder ability, delamination
etc.
How to find the cause?: by cross sections and metallurgic microscope,
Acoustics scanner, 3d X Ray inspection .
Marginal contacts are a reliability issue that must be solved in process
and with component supplier.
Best Regards
Reuven
David Harman
<[log in to unmask] To: [log in to unmask]
COM> cc:
Sent by: TechNet Subject: [TN] FW: BGA question
<[log in to unmask]
>
26/08/2003 00:05
Please respond
to "TechNet
E-Mail Forum.";
Please respond
to David Harman
Hello,
I have seen an increase in problems with electrical testing and it has been
traced to BGAs.
I have a few questions regarding BGA and processes. I am trying to
understand if the problem is process related (SMT) or do I have a vendor
issue with BGA.
1. Open contact between the ball and the package. This is verified by
pressing onto the package while testing. Pressing the package down
causes the board to pass.
2. Visual inspection reveals the ball not touching the PCBA. (You may
have a ball in the middle not touching and the balls on each side
are)
a. Question: With on ball in the middle not touching and the
balls next to it are, is this indicative to SMT process issues
or BGA package issues?
b. Question: What type of inspection can be performed on BGAs
prior to SMT to capture Bad BGA?
i. Is the industry standard 100% or Sample
inspection for out going quality inspection?
c. Question: Is it easy to identify a BGA that has been re-balled
and if so how?
d. Is it customary for distributors to re-ball BGA
e. What other test or inspections can be performed to capture BGA
with open contacts?
f. As indicated above, pressing down the package causes the board
to pass, how do I detect micro cracking of the solder joint?
And what would cause micro cracking?
I am lost at this point and am looking for additional suggestions
and assistance in educating me on BGA.
David Harman
---------------------------------------------------
Technet Mail List provided as a free 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 free 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
-----------------------------------------------------
|
|
|
