| 摘要 |
PURPOSE:To reduce tensile force generated in a thickness direction of a multilayer printed circuit board to a through hole plated layer by employing glass cloth base material epoxy resin having low expansion coefficient or glass cloth base material polyimide resin as a board material. CONSTITUTION:A low expansion coefficient material such as glass cloth base material epoxy resin or glass cloth board polyimide resin is used as the material of an inner layer board 1, foaming fluorine resin is used as a prepreg 2, and the thickness of a through hole plated layer is set to 45mum or more. The used prepreg 2 having low permittivity is formed, for example, by immersing a foaming Teflon film 2a with thermosetting resin 2b, then curing it, and further laminating thermosetting epoxy resins 2c on both front and rear surfaces. Thus, a barrel crack of the plated layer is suppressed (low expansion coefficient), and a transmission delay time can be shortened. |
