LISTSERV - TECHNET Archives - LISTSERV.IPC.ORG

TECHNET Archives

January 2001

TechNet@IPC.ORG

	LISTSERV Archives
	TECHNET Home
	TECHNET January 2001

	Log In
	Register

	Subscribe or Unsubscribe

	Search Archives

Options:	Use Monospaced Font Show Text Part by Default Show All Mail Headers
Message:	[<< First] [< Prev] [Next >] [Last >>]
Topic:	[<< First] [< Prev] [Next >] [Last >>]
Author:	[<< First] [< Prev] [Next >] [Last >>]

Subject:	Re: Circumfrential Void
From:	Craig Ropp <[log in to unmask]>
Reply To:	TechNet E-Mail Forum.
Date:	Thu, 25 Jan 2001 19:12:29 -0600
Content-Type:	text/plain
Parts/Attachments:	text/plain (22 lines)

Sandy,
You didn't mention any type of Desmear process. Resin smear can lead to this. Also, look at where are voids become evident? If you see them after Flash Plating then you know it's upstream from there. If you are desmearing what method are you using (i.e. Plasma, Permanganate, etc)? I would look at your drilling process and associated chiploads as well as bit handling process. Be sure they're in line. If they're too aggressive this can result in debris being left in the hole, thus, if your deburring/sanding/rinsing process is inadequate this debris will detach through subsequent processing and may result in a circumferential voids. Another culprit can be extended dwell time in the Pattern Plate line Microetch. Typically, this leads to differential or complete voiding not circumferential. I hope these hints are helpful. Good Luck!

>>> [log in to unmask] 1/25/01 4:14:08 PM >>>

I am looking for information on the possible causes of circumfrential voids (occuring inside the hole barrel), that I am seeing in the cross sections of multilayer FR4 boards with 10 mil holes with aspect ratio of 10. After drilling, these boards go through Blackhole graphitic carbon / Cu flash / image / Cu pattern plate with Sn as etch resist / strip dry film, etch Cu and strip the Sn/ LPI and HAL.

I would like to find out the cause for these voids. I deeply appreciate any valuable advice on how to fix this problem.

Thanks.
Sandy

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------

ATOM RSS1 RSS2

LISTSERV.IPC.ORG