... July 1st, lead soldering is no longer permitted, and the use of alternative surface refinements for pcb´s has so far provided unsatisfactory results, meaning | PRINTED WIRING BOARDS SHOP | that the lead-free problem has yet to be resolved. The chemical nickel-gold procedure (Imm NiAu) was unsuccessful due to high costs, as was chemical tin. | PRINTED WIRING BOARDS SHOP | Both procedures have proven to be very complicated and sensitive in the further course of processing management. Lead-free solderings also have serious disadvantages, as hot | PRINTED WIRING BOARDS SHOP | air tin surfacing exposes the multi-layers to higher processing temperatures and copper leaching effects. would briefly like to explain why chemical silver is the lead-free | PRINTED WIRING BOARDS SHOP | procedure of the future, and why it will be the focus of our future investments in the field of surface refinement: UNPROBLEMATIC WASTE WATER PROCESSING | PRINTED WIRING BOARDS SHOP | Similarly to chemical tin surfacing, it is a non-electrical, auto-catalytic procedure based on the contrasting electro-negativity of copper and the more “precious” silver. The ...
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... due to high costs, as was chemical tin. Both procedures have proven to be very complicated and sensitive in the further course of processing | PRINTED WIRING BOARDS SHOP | management. Lead-free solderings also have serious disadvantages, as hot air tin surfacing exposes the multi-layers to higher processing temperatures and copper leaching effects. We would | PRINTED WIRING BOARDS SHOP | briefly like to explain why we believe chemical silver is the lead-free procedure of the future, and why it will be the focus of our | PRINTED WIRING BOARDS SHOP | future investments in the field of surface refinement: UNPROBLEMATIC WASTE WATER PROCESSING Similarly to chemical tin surfacing, it is a non-electrical, auto-catalytic procedure based on | PRINTED WIRING BOARDS SHOP | the contrasting electro-negativity of copper and the more “precious” silver. The advantages of this processing manner compared with chemical tin are fewer processing steps and | PRINTED WIRING BOARDS SHOP | lower rinsing temperatures (30 – 50 C°). From the printed circuit board manufacturer’s viewpoint, one strong point in favour of the silver procedure is the | PRINTED WIRING BOARDS SHOP | fact that ...
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... to absorb the laser energy (Rz = 4.8 microns). Recent advances notwithstanding, the most common way to form blind microvias in MLBs by using | PRINTED WIRING BOARDS SHOP | lasers to drill through both copper and dielectric layers still involves two steps. With this technique, a high-power UV DPSS laser ablates through the upper | PRINTED WIRING BOARDS SHOP | copper layer and partly into the dielectric layer below. The laser's fluence is then automatically reduced below the ablation threshold of copper but above that | PRINTED WIRING BOARDS SHOP | of the dielectric. Ablation therefore continues through the dielectric to the copper layer below where the dielectric is cleanly removed from the copper without damaging | PRINTED WIRING BOARDS SHOP | it. This two-step process can be extended, of course, to include more than two layers. In this case, laser fluence would be automatically modulated higher | PRINTED WIRING BOARDS SHOP | for each copper layer encountered and lower for each dielectric layer. A CO2 laser can be used along with the UV DPSS in a dual-laser | PRINTED WIRING BOARDS SHOP | setup that combines the ablation speed of CO2 on dielectric materials ...
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