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62 The PCB Magazine • June 2017 Our latest spreadsheet model now includes, besides power and tolerance normative value for the minimum size, we're also saying what's the minimum size for the voltage you're going to be testing on ESD. When we talk about direct, that means directly applying the ESD to the module. These are new challenges that we didn't real- ly have a big problem with before, and because of this, it also changes the sheet resistivity, be- cause the lower the sheet resistivity the thicker it gets. Maybe it doesn't pass 8,000 volts at 50 ohms per square, but it does pass 8,000 volts at 40 ohms per square. What this has done for us is created a whole new range of products we have to add and we offer different ohmic values. In terms of copper, most of the time half-ounce copper dominates the whole world, but now we're supplying a sig- nificant amount of 12-micron copper. Why? Because for fine-line etching they want thinner copper. We're seeing some 5-micron but that re- quires a carrier we don't like. It's very expensive. If you think the costs are high now, that's real- ly expensive. Also, it's not available in the Unit- ed States so we have to get it from Japan or Tai- wan, whereas 12-micron copper is made here in the U.S. Because not only do you want conduc- tors for high frequency, you also want it for fine line etching. We're seeing smoother surfaces and thinner coppers. All this of course is still half-ounce so what that means is when we add six or eight products now we have 20 products, and since we basically ship from stock, rather than man- ufacture to order because the lead time would be too long, it requires us to now inventory a A DEEP LOOK INTO EMBEDDED TECHNOLOGY Figure 4: MEMS microphone sub-panel with projection to module shown. Figure 5: MEMS microphone PCB array with exposed planar resistors.