Issue link: https://iconnect007.uberflip.com/i/1361971
68 PCB007 MAGAZINE I APRIL 2021 Hunrath: ere has been a need for some- thing that has the performance advantages of polyimide without some of the drawbacks. When I saw the data from Isola on this mate- rial, I was really impressed with its CAF per- formance. Gay: We've actually had four different OEM tests that have been run all the way up into the 1500-volt DC range. You're looking at both hole wall-to-hole wall at various spac- ings and then also Z-axis spacing. We've seen that at 1,500 volts, you can run the material up to 2,000 to 3,000 hours in an accelerated life test. Now with the voltages increasing, we will have to go higher than that, maybe up to 3,000 volts or possibly higher, but when you do an accelerated life test, you're trying to test multiples of the actu- al operating voltage. For example, 460 VDC might be a pretty common volt- age for some of these su- percharging stations to operate. ose invert- ers that are in the car get very hot, very easi- ly. is type of material is going to be a solution for those specific boards within the interconnec- tion of the car and the charging station. Hunrath: If you put that into perspective, pass- ing a 100-volt CAF test at 1,000 hours is con- sidered very good. To do 1,500 volts for 3,000 hours is off the chart. Johnson: It would seem this is a good response to some of the automotive industry require- ments regarding charging and battery manage- ment. Gay: What's interesting is that the construction set in those tests has included 7628 glass and automotive folks want the least cost option to build the boards out of it. Just a couple of these tests are using 7628 and the hole wall-to-hole wall performance is great at these very high voltages at tight spacing. It's pretty interesting chemistry that allows you to do that with 7628 glass. Hunrath: I would think that probably comes from a combination of the fracture toughness and the resin's ability to bond to the glass fabric. Gay: Yes, definitely. Johnson: Did you say that you've had three or four OEMs working with you or working with this material? Gay: Yes, several auto- motive OEMs have done tests, but we're also looking at applications outside the automotive segment. ey are look- ing for the attributes like burn-in board or ATE type applications where you're seeing repeated thermal cycling. at re- peated thermal cycling in a typical burn-in board has numerous slots on a given board and that's going through four or five cycles for that chip set so that they can test it. It's loaded again, put back in the oven and thermal cycled again, then they take it out and load more chips. is happens repeatedly. As the number of sockets is reduced on that test board, it reduces the amount of throughput. When you get to a certain number of sockets that are defective or not functioning, then you have to pull that board out and replace it with another board. is type of material would give the test equipment the ability to run more cycles and last longer in their test system, thus reducing the overall cost.