6 Layer stackup from Advanced PCB Layout Course
Tom Yunghans , 11-23-2021, 01:25 PM
Hi Robert,
I attached a 6 layer stackup you recommended from your Advanced PCB Layout Course. I was curious about the materials used in the center between layers 3 and 4. It consists of two cores of 7628M material with two layers of prepreg on either side of it. I understand from your comments that you wanted that gap between layer 3 and 4 to be large since you wanted the signals on layer 3 to be closer to layer 2 than layer 4. Since that gap is large does it need to consist of core material and not just more or thicker layers of prepreg? I thought a "core" was cured dielectric material with copper on both sides. In this case, does the copper on both sides of those cores used in the middle have to be removed or do they sell cores with no copper?
Thank you!
I attached a 6 layer stackup you recommended from your Advanced PCB Layout Course. I was curious about the materials used in the center between layers 3 and 4. It consists of two cores of 7628M material with two layers of prepreg on either side of it. I understand from your comments that you wanted that gap between layer 3 and 4 to be large since you wanted the signals on layer 3 to be closer to layer 2 than layer 4. Since that gap is large does it need to consist of core material and not just more or thicker layers of prepreg? I thought a "core" was cured dielectric material with copper on both sides. In this case, does the copper on both sides of those cores used in the middle have to be removed or do they sell cores with no copper?
Thank you!
ibocakir06 , 11-25-2021, 11:54 PM
I think there is something wrong. 2x7628 you see in the middle must be a prepreg. There is no core without copper.
binayak , 11-28-2021, 08:25 PM
Yes, there is something wrong with the dielectric materials used in between layers L3 & L4. A core needs copper on both sides.
robertferanec , 11-29-2021, 08:07 AM
I do not know how they built it - but this was the stackup they sent me. Maybe it is possible to buy just the glass fabric? https://www.isola-group.com/wp-conte...ufacturing.pdf
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