Abstract: This invention is aimed at providing a wafer-level package which is capable of relaxing the stress in a chip-size package and exalting the reliability of the operation of mounting on a printed board and a method for the production thereof. This invention is directed toward a wafer-level package of a semiconductor substrate possessed of either or both of an electrode part and a wiring layer connected to an electrode part, which is provided on the semiconductor substrate with an insulating layer formed mainly of a fluorene skeleton-containing resin and on the electrode part with one step or a plurality of steps of posts, and on the posts with bumps formed of electroconductive balls and a method for the production thereof.

Abstract: This invention relates to an insulating resin composition which exhibits high impact resistance and heat resistance and good adhesiveness to the plating metal, is selectively etchable by a permanganate salt commonly used in a plating operation and suited for an insulating layer in multilayer wiring boards. The insulating resin composition is a photo-polymerizable or thermally polymerizable resin composition comprising 3-10 parts by weight of a crosslinked elastic polymer per 100 parts by weight of a resin component (excluding the crosslinked elastic poly and including monomers) and said crosslinked elastic polymer has carboxyl groups and is dispersed with an average secondary particle diameter in the range of 0.5-2 &mgr;m.

Abstract: This invention relates to an insulating resin composition which exhibits high impact resistance and heat resistance and good adhesiveness to the plating metal, is selectively etchable by a permanganate salt commonly used in a plating operation and suited for an insulating layer in multilayer wiring boards. The insulating resin composition is a photo polymerizable or thermally polymerizable resin composition comprising 3-10 parts by weight of a crosslinked elastic polymer per 100 parts by weight of a resin component (excluding the crosslinked elastic poly and including monomers) and said crosslinked elastic polymer has carboxyl groups and is dispersed with an average secondary particle diameter in the range of 0.5-2 &mgr;m.

Abstract: A process is disclosed for preparing of aromatic polyester-polystyrene block copolymers which comprises subjecting preferentially styrene polymers (A) having terminal functional groups reactive with acid chloride groups and an excess of aromatic dicarboxylic acid dihalides (C) to condensation and then subjecting continuously the resultant mixture and aromatic dihydroxy compounds (B) to interfacial polymerization at the ratio (A)/[(B)+(C)] by weight of 5/95 to 80/20, without separating reaction products of styrene polymers (A) and aromatic dicarboxylic acid dihalides (C), and the block copolymers thus prepared contain a small amount of uncopolymerized styrene polymers, have long aromatic polyester segments, show low birefringence, good transparency, exceptionally low birefringence, low melt viscosity, and good mechanical strength, and are particularly useful as materials for optical instruments.

Abstract: A process is disclosed for the preparation of aromatic polyester-polystyrene block copolymers by solution polycondensation of styrene polymers (A) having terminal functional groups reactive with acid halide or hydroxyl groups, aromatic dihydroxy compounds (B), and aromatic dicarboxylic acid dihalides (C) at (A)/[(B)+(C)] (by weight) of 5/95 to 80/20 and the polymers are suitable as molding materials for optical instruments for their good transparency, particularly low birefringence, low melt viscosity, and good mechanical strength.