Think & Tinker, Ltd.
P.O. Box 1606, Palmer Lake, CO 80133
Tel: (719) 488-9640, Fax: (866) 453-8473
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Tel.: (719) 488-9640
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M115i Dry Film Photoresist
Specifications and Processing Guide
Photoresist order form

Process Parameter Detail / Notes Range Optimum
Pre-lamination drying time oven @ 110°C±5°C 15 - 20 min. 15 min.
Lamination temperature Think & Tinker Dry-film
115°C±5°C 110°C
speed 3 - 6 ft./min 4 ft./min. (1)
Exposure Stouffer Step 21 step, variable neutral density wedge 10 - 12 11
energy energy density in miliJoules per square centimeter (350 - 420 nm) 150-300
time Thinker & Tinker UV Source Kit calibrate each roll calibrate each roll
color initial - glossy light blue
after exposure - glossy blue
Post-exposure hold time time the total hold time between lamination and development should not exceed 8 hours 0.25 - 8 hours 15 min.(2)
Development breakpoint the image should appear to be 100% developed to the naked eye. 50 - 65% of total dev. time 60% of total dev. time (3)
temperature bubble assisted developers 29°C±6°C 26°C
spray developers 31°C±2°C 31°C
chemistry anhydrous sodium carbonate (soda ash, weight%) (4)
sodium carbonate monohydrate (weight %)
0.80 - 0.90%
0.95 - 1.05%
Pre-etch drying time 100°C±5°C - 5 min.
Stripping chemistry NaOH (sodium hydroxide) @ room temp. 1.5% - 3% 1.5%


  1. With a Think & Tinker Dry Film Laminator, the midrange position of the speed control knob (at 12:00) corresponds to a web speed of approximately 4 feet per minute.
  2. Strictly speaking, 4615 can be developed immediately after exposure. We have found, however, that for fine line circuit patterns, letting the panel sit for 15 minutes after exposure enhances the adhesion of the thin traces to the underlying copper.
  3. The recommended breakpoint for 4615 is 50% of the way though the developing time. The image has reached "breakpoint" when,to the naked eye, the pattern looks to be fully developed. Visual breakpoints can be very misleading. A more accurate evaluation can be made by carefully running your ungloved fingers over the surface of the panel. If you can feel a distinctly slimy or slippery coating in areas that appear to be free of photopolymer, the image needs more time in the developer.
  4. Two forms of sodium carbonate are commercially available. Both can be used to prepare DF 4615 developing solution:
    • Soda ash (anhydrous sodium carbonate); Na2CO3
    • Sodium carbonate monohydrate: Na2CO3*H2O

    The monohydrate form contains 17% water and is the more chemically stable form of sodium carbonate.
  5. If properly imaged, the dry-film should be tough enough after developing to scrub with a kitchen sponge to remove any residual traces of adhesive or photopolymer from the exposed copper areas. This may be necessary if tray or bubble assisted developing is used. Boards developed with high pressure spraying equipment do not generally need this extra attention.
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On the web since 1994

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Copyright © 1994 - 2014 Think & Tinker, Ltd. Updated 2/13/2014 8:36:56 AM