TECHNET Archives

March 2003

TechNet@IPC.ORG

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 >>]

Print Reply
Subject:
From:
paul reid <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 28 Mar 2003 11:49:18 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (85 lines)
I have found mouse bites on inner layers related to contaminated circuits.

I am assuming you are talking about a "print and etch" application. I also
assume the mousebite is circular and are on the edge of traces. I also
assume that there are no full opens involved. The mouse-bites look like the
edge of a circle or of a bubble. If these assumptions are wrong please
disregard the following.

One type of mousebite occurs typically by a droplet that contaminates a
small area of the copper before resist lamination. The resist does not
properly bond to the base copper at that spot and areas were the image
bisects the contaminate will have very slight degree of resist lifting
during developing or etching. The enchant undercuts the resist and the
classic circular mousebite appears.

Another type of mouse bite is cause by contamination on the resit laminated
boards before or after developing. If a droplet of stripping or developing
solution lands on the surface of the resist it can slowly attack the resist
causing it to swell and lift off the copper.

Look for the mousebites before developing, etching and again before
stripping the resist. They will typically be a lighter color, circular and
of correct size. The size of the circle may be an indicator of the source of
the contaminat. The condition of lifted resist may indicate the cause of the
lifting.

New developing solutions may cause the "foot" of the resist to be weaker
allowing this condition to occur.  Check the break point, temperature and
the ph of the developer solution. The same applies for the etcher check; the
break point, pH and temp.

Eliminate the source of contamination. Cleaning and drying of the laminate
before resist lamination needs to be reviewed. I had a pumice scrubber once
that sprayed a very fine mist that contaminated cleaned boards that were
drying near by and produced random mousebites.

Note: New developer solutions may attack resist also but I would expect that
the defects include wide line width reduction and opens. A picture would be
useful.

PR

-----Original Message-----
From: Franklin D Asbell [mailto:[log in to unmask]]
Sent: Friday, March 28, 2003 9:55 AM
To: [log in to unmask]
Subject: [TN] Mousebites on innerlayers


What would cause 'mousebite' appearing defects along the edges of
innerlayers?

We've started seeing them on one lot, about 75% of 30 layers. There are
about 5 or 6 on an 16X21 size layer, extending across the trace almost to
90% plus...

Any thoughts would be appreciated.

Franklin

---------------------------------------------------
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/html/forum.htm 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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------

ATOM RSS1 RSS2