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February 1997

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Subject:
From:
Bob Mesick <[log in to unmask]>
Date:
Thu, 20 Feb 1997 15:11:19 -0800 (PST)
Content-Type:
text/plain
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text/plain (88 lines)
In general:

The efficiency of the collimination will determine the amount of undercut
you get on the photoresist.  The thinner the resist you use the finer the
traces you can image with a given light source.  Greater collimination will
give you the ability to stick the the same resist thickness and get finer
traces.

For example, liquid photoresist, 125 micro inches thick, can image 3 micron
x 3 micron (80 micro inches - 1x1 on glass plates for LCDs) with realtively
uncolliminated light routinely.

Tricks to increase your systems capability include placing a flat black grid
to block light that is emitted over a certain angle in your exposure system.

Increase developing efficiency by increasing the quanity of spray nozzles
and decreasing spray angle to minimize undercut.

Same as above for etcher.

Use very thin copper to start.

Go to a liquid resist.  !:-)

For a start, I'd use thin foil, thin/fast speed resist, existing light
source, and do some step tables to see what I could get.  If I was close but
not quit there, try a grid baffle in the exposure unit to block stray light.
Most units are pretty collimated in the center already, as you get to the
outside, you start to loose it.  

Good Luck,

Bob Mesick
Remco Engineering
remco.com/home.htm




>Date: Thu, 20 Feb 1997 03:47:15 EST
>From: [log in to unmask]
>To: [log in to unmask]
>Subject: Collimation or not?
>Message-Id: <[log in to unmask]>
>Content-Type: text/plain; charset=US-ASCII
>Content-Transfer-Encoding: 7bit
>
>    \0
>   TO:         I4235700 IBMMAIL   IBM Mail exchange
>
>   FROM:       DWALLACE EX2       D.Wallace        - Process Control Mngr
Dunsdale
>
>   DATE:       20 February 1997
>   SUBJECT:    Collimation or not?
>
>    I am interested in some user input regarding collimated light
>    source exposure units for imaging multilayer innerlayers.
>    Currently, we use ORC (Japan) point light source units in
>    combination with a glass to glass vacuumed print frame and we are
>    able to achieve very acceptable yields on 100 micron track / gap
>    technology. We wish to improve this capability down to 50 micron
>    track / gap. Is collimation the only practical way of achieving
>    this? Are there any other benefits in using this type of light
>    source? What, if any, are the drawbacks?
>
>    Thanks in advance for any imput.
>
>    David H Wallace Process Control Manager Exacta Circuits Limited.
>

>
Remco Engineering (remco.com/home.htm)
Industrial Water and Wastewater Treatment Systems
San Luis Obispo, California  USA

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