... .PI Stiffener, ENIG Finishing Stack up : 1 layer double side CCL + 4 layer single side CCLBase material: 1/2mil PI and 1milCCL: 1mil ... PI, 1/3oz, adhesiveless, double ED copperCCL: 1/2mil PI ... , 1/3oz adhesiveless, single side ED copperCover layer: 1/2mil, 15umSurface ...