Abstract: A paste for via-hole filling is provided, and the paste comprises at least (a) 30-70 volume % of conductive particles whose average diameter ranges from 0.5 to 20 .mu.m and whose specific surface area ranges from 0.05 to 1.5 m.sup.2 /g, and (b) 70-30 volume % of resin comprising at least 10 weight % of epoxy resin comprising at least one epoxy group per molecule, in which the total amount of a hydroxyl group, an amino group and a carboxyl group is not more than 5 mol % of the epoxy group, and the epoxy equivalent ranges from 100 to 350 g/eq. The conductive paste for filling via-holes and a printed circuit board comprising thereof can be used to provide an inner-via-hole connection between electrode layers without using a through-hole plating technique. The conductive paste comprises a metallic particle such as copper, an epoxy resin, a hardener and a dispersant if necessary. The paste having low viscosity and low volatility is used to fill holes disposed in a laminated substrate.

Abstract: An improved semiconductor unit package is disclosed. This package is implemented by a semiconductor device having an electrode pad, a substrate having a terminal electrode, a bump electrode formed on the electrode pad, a conductive adhesion layer with flexibility, and an encapsulating layer formed by curing a composition the viscosity and thixotropy index of which are below 100 Pa.multidot.s and below 1.1, respectively. Such a composition essentially consists of (A) a resin binder that contains, for example, a polyepoxide, an acid anhydride, and a rheology modifier and (B) a filler. The rheology modifier is one capable of impeding interaction between a free acid contained in the acid anhydride and a polar group at the surface of the filler. An encapsulant with improved flowability is used, so that the encapsulant readily flows and spreads to fill a gap between the semiconductor device and the substrate with no air bubbles. This achieves semiconductor unit packages with high reliability and productivity.