Page 147 - PCMI Journal December 2020
P. 147
Dry Film Resist Control Topics in Photo Chemical Milling Processes Presented by: Sean Hill, Project Manager | Eternal Technology Corporation, US
12/18/20
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Collimated Light
Advantages
§ High Resolution/Fine Lines
§ Light enters at a 90 degree angle- light rays are very close to parallel
§ Intensity is uniform
Limiting Feature Resolution: 1.5 to 2.0 Mil range
Disadvantages
§ Sensitive to dust and debris on mirrors and reflectors
§ Higher cost
§ Higher maintenance
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Lamp Intensity
• Controlled using radiometer or by measuring exposure time: Power (mW/cm2) x Time (sec) = Energy (mJ/cm2)
• Decreases as lamps age.
• Dirty reflectors and exposure frames reduce intensity at the print frame.
• Some Printers have internal radiometers built in.
Issue 136 December 2020 PCMI Journal 147
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