Dry-film Soldermask Specifications and Processing

Think & Tinker, Ltd.
P.O. Box 1606, Palmer Lake, CO 80133
Tel: (719) 488-9640, Fax: (866) 453-8473
Sales: Sales@thinktink.com, Support: Support@thinktink.com

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Tel.: (719) 488-9640
Fax: (719) 481-0464

DF 8130 Dry Film Soldermask
Specifications and Processing Guide

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 Laminator	110°C±5°C	110°C
Lamination	speed	Think & Tinker Dry-film Laminator	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 mJ/cm²	-
	time	Thinker & Tinker UV Source Kit	calibrate each roll	calibrate each roll
	color	initial - matte medium green after exposure - matte green
Post-exposure hold time	time	the total hold time between lamination and development should not exceed 8 hours	0.5 - 8 hours	30 min.
Development	breakpoint	the image should appear to be 100% developed to the naked eye.	40 - 60% of total dev. time	50% of total dev. time ⁽²⁾
	temperature	bubble assisted developers	41°C±2°C	41°C
	temperature	spray developers	43°C±2°C	43°C
	chemistry	anhydrous sodium carbonate (soda ash, weight%) ⁽³⁾ sodium carbonate monohydrate (weight %)	0.80 - 0.90% 0.95 - 1.05%	0.85% 1.0%
Cure⁽⁴⁾	exposure	UV energy in Joules per square centimeter (350 - 420 nm)	3 - 5 J/cm²	4 J/cm²
Cure⁽⁴⁾	bake	145°C±5°C	-	1 hr.

Notes

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.
The recommended breakpoint for 8130 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.
Two forms of sodium carbonate are commercially available. Both can be used to prepare DF 8130 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.
During the final curing step, the board must be baked first and then exposed to the UV source until the prescribed exposure is attained. Exposure can be measured by an International Light A 309 Lightbug. If you do not have a light meter, you can simply expose the baked board to your imaging source for 10 to 12 times as long as your imaging exposure.
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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Established 1990

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