Mike,
     In addition to agreeing with Eric's employee comments I would like to 
offer a few other observations on the subject.  The majority of shops that 
produce .008 mil lines/spaces that I have seen, do not have controlled 
'clean' rooms.
     I have also been in at least two shops that boasted of .003 mil 
capability that had NO clean room or even positive pressure in the imaging 
areas.  In both cases when ask about production yields, prerehearsed 'tap 
dance' answers were given.  Neither shop knew or was willing to share their 
actual shop defect rates based on the their lack of air born contamination 
control in the imaging areas.  I have also seen many shops with what was 
advertised as a clean room but noticed there was no positive pressure.
     Basically, from a sales point they look cool but without enough 
positive pressure to keep out contaminates from the other processes, both 
chemical and dust, the actual 'clean' value of the room is near zero.  In my 
opinion, considering your .008 requirement description, I would steer away 
from using a class "100K Clean Room" title by procedure.  If you do, some 
auditor will want to see your Mil testing proof.  I don't believe you need 
to go through that.
      A more practical approach would be to write your procedure to 
specify/control the items you mentioned (since they are already in place) 
with one addition.  In this procedure close your control loop by including 
the MRB function.   Have your production defects reviewed daily/weekly by 
MRB.  A minimum effort by your MRB group should be able to easily identify 
defects caused by imaging contamination.   Simply tracking these defects 
will have many benefits.  It will document the quality capability of your 
imaging process.  It will provide justification for any needed improvements. 
 It can demonstrate the 'no added value' of any steps that you have deleted. 
 It will also serve to impress the auditors that your actually do monitor 
your image process quality and follow your procedure.
      This approach will allow you to fine tune your 'clean' room to fit the 
quality needs of your other processes without over kill.

         Norm Dill

 ----------
From: E.Janssens@MT0004
To: [log in to unmask]
Subject: FAB: IMAGE ROOM CLEANLINESS
Date: Friday, October 11, 1996 3:18AM

In-Reply-To: The letter of Friday, 11 October 1996 02:20


Dear Mike,

  Based on my experience with reduced dust level enviroments for
plotter rooms I want to make a non technical remark.
  Dust levels are reduced by acting on 3 levels: dust generation
prevention, dust entrance prevention and dust removale. Every clean
room systems supplier can offer you technical solutions.
  But the system is only as good as it is used. The best systems can
be ruined by the operators. The people are the biggest and most
unpredictable dust source. I suggest you concentrate more on people
and their behaviour.
  Some suggestions:
   - make a clean programme and have it respected
   - no food and beverage in the yellow room
   - no papers or magazines
   - have operators wearing a headcap (and gloves?) as a reminder
that they are in a clean room
  A good discipline in a good enough enviroment will bring you more
than an expensive clean room manned by careless operators.
  Success

   Eric Janssens

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