2 added 1 characters in body edited Jul 22 '11 at 13:30 stevenvh 134k1515 gold badges426426 silver badges637637 bronze badges I think 105$$\\mu\$$ is the thickest you can get, but I can see no reason why you wouldn't get it on inner layers. A PCB is just a stackup of epoxy, copper and glass fiber. You can play with thickness at will. Thicker inner layers won't be as efficient, of course, since they can't give off their heat to the environment easily; the epoxy is a poor thermal conductor. We had a design which demanded 16A over several traces, and ended up with 4mm traces top and bottom, and big diameter vias on them from beginning to end. No inner traces, I don't recall copper thickness. I think 105$$\\mu\$$ is the thickest you can get, but I can see no reason why you wouldn't get it on inner layers. A PCB is just a stackup of epoxy copper and glass fiber. You can play with thickness at will. Thicker inner layers won't be as efficient, of course, since they can't give off their heat to the environment easily; the epoxy is a poor thermal conductor. We had a design which demanded 16A over several traces, and ended up with 4mm traces top and bottom, and big diameter vias on them from beginning to end. No inner traces, I don't recall copper thickness. I think 105$$\\mu\$$ is the thickest you can get, but I can see no reason why you wouldn't get it on inner layers. A PCB is just a stackup of epoxy, copper and glass fiber. You can play with thickness at will. Thicker inner layers won't be as efficient, of course, since they can't give off their heat to the environment easily; the epoxy is a poor thermal conductor. We had a design which demanded 16A over several traces, and ended up with 4mm traces top and bottom, and big diameter vias on them from beginning to end. No inner traces, I don't recall copper thickness. 1 answered Jul 19 '11 at 3:01 stevenvh 134k1515 gold badges426426 silver badges637637 bronze badges I think 105$$\\mu\$$ is the thickest you can get, but I can see no reason why you wouldn't get it on inner layers. A PCB is just a stackup of epoxy copper and glass fiber. You can play with thickness at will. Thicker inner layers won't be as efficient, of course, since they can't give off their heat to the environment easily; the epoxy is a poor thermal conductor. We had a design which demanded 16A over several traces, and ended up with 4mm traces top and bottom, and big diameter vias on them from beginning to end. No inner traces, I don't recall copper thickness.