Interlayer dielectric layer for printed wiring board, printed wiring board, and method of producing the same

Abstract

A method of forming a multilayer printed wiring board including forming a yet-to-cure interlayer dielectric layer by applying or attaching, to a dielectric substrate, an interlayer dielectric material of liquid or dry film including one or more of thermosetting resin, mixture of thermosetting and thermoplastic resins, photosensitized thermosetting resin, mixture of photosensitized thermosetting and thermoplastic resins, and photosensitive resin, softening the dielectric layer, pressing mold having convexities onto the softened dielectric layer to form concavities for conductor and concavities or through-holes for viaholes, cooling or heating the softened dielectric layer to temperature at which shapes of the concavities and/or through-holes in the dielectric layer are maintained, removing the mold from the dielectric layer, heating, or irradiating ultraviolet rays to, the dielectric layer, and curing, by heating, the dielectric layer, and forming the circuits and viaholes by forming a conductive material in the concavities and/or through-holes in the cured dielectric layer.

1 . A method of forming a multilayer printed wiring board, comprising: 
 forming a yet-to-cure interlayer dielectric layer by applying or attaching, to a dielectric substrate, an interlayer dielectric material of a liquid or dry film type comprising at least one resin selected from the group consisting of a thermosetting resin, a mixture of thermosetting resin and thermoplastic resin, a photosensitized thermosetting resin, a mixture of photosensitized thermosetting resin and thermoplastic resin, and a photosensitive resin;    softening the yet-to-cure interlayer dielectric layer;    pressing a mold having convexities onto the softened interlayer dielectric layer so as to form concavities where conductor circuits are to be formed and concavities or through-holes where viaholes are to be formed in a surface of the interlayer dielectric layer;    cooling or heating the softened interlayer dielectric layer to a temperature at which shapes of the concavities and/or the through-holes formed in the interlayer dielectric layer are maintained;    removing the mold from the interlayer dielectric layer;    heating, or irradiating ultraviolet rays to, the interlayer dielectric layer from which the mold has been removed, and then curing, by heating, the interlayer dielectric layer to provide a cured interlayer dielectric layer; and    forming the conductor circuits and the viaholes by forming a conductive material in the concavities and/or the through-holes formed in the cured interlayer dielectric layer.    
   
   
       2 . The method according to  claim 1 , wherein the interlayer dielectric material further includes flaky particles.  
   
   
       3 . The method according to  claim 1 , further comprising roughing a surface of the cured interlayer dielectric layer with a surface roughing liquid after the heating or irradiating of the interlayer dielectric layer.  
   
   
       4 . A method of forming a multilayer printed wiring board, comprising: 
 forming a yet-to-cure interlayer dielectric layer by applying or attaching, to a dielectric substrate, an interlayer dielectric material of a liquid or dry film type comprising at least one selected from the group consisting of resin particles, elastomer particles and inorganic particles soluble in a surface roughing liquid dispersed in a resin matrix comprising at least one resin selected from the group consisting of a thermosetting resin, a mixture of thermosetting resin and thermoplastic resin, a photosensitized thermosetting resin, a mixture of photosensitized thermosetting resin and thermoplastic resin, and a photosensitive resin;    softening the yet-to-cure interlayer dielectric layer;    pressing a mold having convexities onto the softened interlayer dielectric layer so as to form concavities where conductor circuits are to be formed and concavities or through-holes where viaholes are to be formed in a surface of the interlayer dielectric layer;    cooling or heating the softened interlayer dielectric layer to a temperature at which shapes of the concavities and/or the through-holes formed in the interlayer dielectric layer are maintained;    removing the mold from the interlayer dielectric layer;    heating, or irradiating ultraviolet rays to, the interlayer dielectric layer from which the mold has been removed;    curing, by heating, the interlayer dielectric layer to provide a cured interlayer dielectric layer;    roughing a surface of the cured interlayer dielectric layer with a surface roughing liquid; and    forming the conductor circuits and the viaholes by forming a conductive material in the concavities and/or the through-holes formed in the cured interlayer dielectric layer.    
   
   
       5 . A method of forming a multilayer printed wiring board, comprising: 
 forming a yet-to-cure interlayer dielectric layer by applying or attaching, to a dielectric substrate, an interlayer dielectric material of a liquid or dry film type comprising at least one resin selected from the group consisting of a thermosetting resin, a mixture of thermosetting resin and thermoplastic resin, a photosensitized thermosetting resin, a mixture of photosensitized thermosetting resin and thermoplastic resin, and a photosensitive resin;    softening the yet-to-cure interlayer dielectric layer;    pressing a mold, which has convexities and irregularities on the convexities, onto a surface of the yet-to-cure interlayer dielectric layer so as to form, in the surface of the yet-to-cure interlayer dielectric layer, concavities where conductor circuits are to be formed, concavities or through-holes where viaholes are to be formed, and anchors on surfaces of the concavities;    cooling or heating the softened interlayer dielectric layer to a temperature at which shapes of the concavities and/or the through-holes formed in the interlayer dielectric layer are maintained;    removing the mold from the interlayer dielectric layer;    heating, or irradiating ultraviolet rays to, the interlayer dielectric layer from which the mold has been removed;    curing, by heating, the interlayer dielectric layer to provide a cured interlayer dielectric layer; and    forming the conductor circuits and the viaholes by filling a conductive material in the concavities and/or the through-holes formed in the cured interlayer dielectric layer.