Issue link: https://iconnect007.uberflip.com/i/1038326
42 PCB007 MAGAZINE I OCTOBER 2018 Johal: Yes, recipe changes from a technology point of view can add value during processing for the adhesion promoter because the dielec- tric materials vary. GreenSource can link a spe- cific barcode job to a particular process recipe. In this case, the conveyor speed may be adjust- ed to provide different etch depths for the se- lected dielectric and enhance the performance of the adhesion promoter. Holden: Normally, that sort of adjustment has to be done by humans or by the batch. That's a key thing here—it's all done automatically. The digital recipe changes the actual physics that occur in the line. Foley: As Kuldip said, it's driven by the etch rate/depth, and several things could change your etch rate: speed, temperature, or chemis- try. At the front of the line is a loader followed by an acid cleaner followed by a rinse, an alka- line cleaner followed by a rinse, and then acti- vation for the actual BondFilm. BondFilm is a modified peroxide-sulfuric etch with organics. Finally, the process concludes with a rinse fol- lowed by rinsing and drying. Holden: And for inner layer? Foley: For inner layer, the etch is unique. A typical problem in a horizon- tal etch system is puddling on the top of the layer, result- ing in a more aggressive etch on one side. It's hard to con- trol top to bottom consistent- ly. To solve this, GreenSource has two etchers. The bottom is etched in the first half, and then it goes through the AWP flipper, which flips the pan- el and etches what was on the top in the second half of the line. No top etching means no puddling. It's pretty nice. Patty Goldman: Do all the dif- ferent acid coppers use the same tank? Foley: Some have different holding tanks. De- pending on what GreenSource is running that day or week, they will pump over whatever acid copper is needed, transfer it back to the holding tanks, and bring the next one over as necessary. They use the same electrolytic tool but different holding tanks. Dreiza: I'd like to point out the condensers on our desmear line. Any exhaust from the equip- ment becomes condensed back into the unit, which benefits a considerable reduction in chemistry usage and improves the overall en- vironmental impact of any operations. Holden: Speaking of which, I notice the venting is pretty minimal coming off these machines. Dreiza: The condensers significantly reduce the amount of chemistry needed for the line. That's just one example of many features on the line that reduce chemistry consumption. Matties: There's a lot of thought and planning in these lines. Johal: Alex has added nuances into the system by planning for tremendous flexibility in each process. He wants to be able to process thick panels and thin HDI panels as well, and that Figure 5: Back-side view of modules with fine filtration units.