Abstract: Disclosed is a printed circuit board, and a method of preparing a printed circuit board, which possesses a coefficient of thermal expansion substantially similar to that of silicon for use in direct semiconductor chip attach structures and similar solder mounted devices. The printed circuit board is fabricated from prepreg having a thermosetting resin and a reinforcement layer consisting of non-woven aramid mat or a liquid crystalline polymer paper. The composite dielectric layer optionally includes plated through holes which are either filled or non-filled, and one or more thin film redistribution layers to provide high density electronic packages. The design places the solder pads at the PTHs where needed. The redistribution layer can be formed using photoimagable dielectrics or laminated controlled-CTE composites and laser via imaging.

Abstract: The present invention relates to a method for planarizing circuit board apertures wherein a photoimageable film composition comprising a photoimageable dielectric composition and a support film is employed to fill the circuit board apertures. Precircuitized and postcircuitized embodiments are discussed.