Printed wiring board and a method of manufacturing a printed wiring board

摘要

[Subject Matter] To provide a printed wiring board in which no warping occurs even if interlayer insulation layers without core material are laminated on a core substrate.;[Solution(s)] To lower the thermal expansion coefficient (CTE) to 20˜40 ppm, inorganic particles are added to core substrate 30 formed by impregnating glass-cloth core material with glass-epoxy resin. Furthermore, thickness (a) of core substrate 30 is set at 0.2 mm, thickness (b) of upper-surface-side first interlayer insulation layer (50A) at 0.1 mm, and thickness (c) of lower-surface-side second interlayer insulation layer (50B) at 0.1 mm. In setting so, using thin core substrate 30 and interlayer insulation layers (50A, 50B) without core material, it is thought that warping does not occur in the printed wiring board.

主权项

1. A printed wiring board, comprising:
a core substrate formed of a single layer having a thickness in a range of from about 0.06 mm to about 0.40 mm and a thermal expansion coefficient α in a range of from 5×10−6 to 8×10−6; a first conductive circuit formed directly on a first surface of the core substrate; a second conductive circuit formed directly on a second surface of the core substrate on an opposite side with respect to the first surface; a through-hole conductor formed in a penetrating hole extending from the first surface to the second surface of the core substrate and connecting the first conductive circuit and the second conductive circuit; at least one first interlayer insulation layer formed on the first surface of the core substrate; and at least one second interlayer insulation layer formed on the second surface of the core substrate, wherein the core substrate, the first interlayer insulation layer and the second interlayer insulation layer satisfy an equation, α/(E×(a+b+c))=0.5×10−6˜2.5×10−6/GPa·mm·K, where the thermal expansion coefficient of the core substrate is set at α, Young's modulus of the core substrate is E, a thickness of the core substrate is a, a sum of a thickness of the first interlayer insulation layer is b, and a sum of a thickness of the second interlayer insulation layer is c.