There are three basic types of printers on the market. 

- Flood Systems - 
Have reflectors as large as the exposure frame that contain the lamp. The 
reflectors are made from a number of flat facets of aluminum that are mirror, 
brush, or dimple finish. The lamps are mercury capillary, or medium pressure 
arc. These systems produce soft illumination. They are the least sensitive to 
dust and debris but are limited in resolution, are very sensitive to vacuum 
contact and have a significant difference in performance across the exposure 
plane. This is due to the differences from the center compared with the 
reverse light angles caused by the side reflectors. Capillary lamps have from 
10 - 15k exposures life.

- Collimated Systems - 
Have high pressure short arc lamps in an elliptical reflector that refocuses 
the lamp on an optical integrator, the rays are then bounced from a parabolic 
collimating mirror before striking the exposure plane. The system has the 
least sensitivity to out of contact exposures. The tight optical angles tends 
to reproduce flaws in the glass, and the artwork. There is also a high 
sensitivity to dust and debris. These systems are the more costly to purchase, 
and have a higher operating cost due to lamp cost and life, power consumption, 
air conditioning load and the required cleanliness of the environment. Yields 
are often a trade of shorts for opens. Lamps have a 750h to 1000h life, there 
is an explosion possibility if lamps are run too long.

- Point Source Systems - 
Have a compact optical system, lamp plus reflector that is typically 25 cm 
square.  These systems use medium pressure additive lamps that can be 
manufactured with a spectrum which optimizes the resolution of the 
photoresist. They provide a compromise between flood and collimation in 
optical sharpness. On a scale of 1 to 10 with collimation being 1 and flood 
systems rating a 10, the optical sharpness of the point source is 3. The 
higher intensity and favorable spectrum enhance the resolution. As a result of 
the increased resolution over flood systems in combination with a reduced 
sensitivity to flaws and debris of collimated system, the point system tends 
to  produce at higher yields. Lamps are the least costly and have a 1000 - 
2500 hour life. 

	Bert Ohlig





----------
From: 	[log in to unmask]
Sent: 	Thursday, February 20, 1997 12:47 AM
To: 	[log in to unmask]
Subject: 	Collimation or not?


    \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.

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************


***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************