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24 PCB007 MAGAZINE I FEBRUARY 2022 As far as estimation of CO 2 equivalents for water usage, we did not find them to be incred- ibly impactful due to the choice of inputs we utilized, as water production requires a com- paratively low energy input in industrialized countries. Power Usage e power usage of direct metallization is consistently lower than electroless copper by a large factor regardless whether a horizontal or vertical equipment configuration. is is because the baths in an electroless copper pro- cess are greater in number and higher in tem- perature than in the direct metallization pro- cess. An electroless copper line has a: • Cleaner (~50°C) • Conditioner (~52°C) • Micro-etch (~38°C) • Palladium catalyst pre-dip (~25°C) and palladium catalyst bath (~33°C) • Accelerator (~50°C) e actual electroless copper bath (~45°C) is is compared to the standard DM line, which has a: • Cleaner/conditioner (~24°C) • DM bath (~33°C) • Post etch (~34°C) • Blower and dryer Due to this, power usage drops more than 50%, even for double-pass lines which just add an additional conditioner/carbon module. Comparing similar lines side-by-side as in the water example, an equivalent DM line will uti- lize around 62,000 KWH/month, while a verti- cal electroless copper line will be in the range of 147,000 KWH/month. As with water outages, 2021 also saw several periods of time where power rationing was required at many board fabricators in Asia. ose who were running direct metallization were able to supply their customers for longer and with a lower overall usage than those run- ning electroless copper. For estimation of the CO 2 equivalent, which is what is to follow, we converted the KWH using standard methods which can be arrived at on the U.S. EPA web- site. Chemical Ingredients and a Model for Total CO 2 Equivalent While it is too large a topic to break down in this article, the chemical ingredients that are used to make up the total component list in an electroless copper process are numer- ous and in general much more stressful on the environment from the raw materials stage than direct metallization. When building a model for CO 2 equivalent, we utilized actual con- sumption data at customers to create a base- line amount and then backtracked what each quantity of the component would generate in terms of kilograms of CO 2 , using the most uti- lized method of manufacturing. Conversion Figure 5: Power consumption of direct metallization is lower because there are fewer baths with lower bath temperatures.