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24 PCB007 MAGAZINE I JULY 2024 emissions. Certainly, sustainability should be on everyone's list going forward. If one sim- ply calculates the amount of energy required to heat process tanks and the time it takes to process a circuit board through any one pro- cess, it can be shown that processes that reduce production time and use less energy will reduce the carbon footprint and thus green- house emissions. More on this in a future col- umn. Ideal Applications for Direct Metallization With more emphasis on HDI and ultra HDI, ease of use and speed are critical operational must-haves. Advanced packaging is driving higher densities for IC substrates, interpos- ers, and product boards. is necessitates the increased complexity of these boards and sub- strates with ever finer lines and spaces, multi- ple sequential laminations, and smaller diame- ter blind vias. e carbon and graphite-based direct metallization systems are ideally suited for these challenges. e level of complexity is depicted in Fig- ure 1. In addition, the every layer interconnect (ELIC) process is also practiced in the indus- try (Figure 2). With proper material selection, the construc- tions shown in Figures 1 and 2 will improve long-term reliability and withstand the mul- tiple laminations required. e key here is to select materials with low CTE and higher tem- peratures of decomposition. e direct metallization process described in this column will enable faster productivity through primary metallization in contrast with conventional electroless copper. PCB007 Michael Carano brings over 40 years of electronics industry experience with special expertise in manufacturing, performance chemicals, metals, semicon- ductors, medical devices, and advanced packaging. To read past columns, click here. Figure 2: The ELIC process.