Ibiden Company Limited

Honjin En

Naohiro Hirose

Kiyotaka Tsukada

Kouta Noda

Naoto Ishida

Hiroshi Segawa

Kouji Asano

Atsushi Shouda

An opening is formed in resinby a laser beam so that a via hole is formed. At this time, copper foil, the thickness of which is reduced (to 3 &#x3bc;m) by performing etching to lower the thermal conductivity is used as a conformal mask. Therefore, an openingcan be formed in the resinif the number of irradiation of pulse-shape laser beam is reduced. Therefore, occurrence of undercut of the resinwhich forms an interlayer insulating resin layer can be prevented. Thus, the reliability of the connection of the via holes can be improved.

Multilayered printed circuit board and manufacturing method thereof

Mesh holesandof upper solid layersand upper solid layersare formed to overlie on one another, so that the insulating properties of interlayer resin insulating layersare not lowered. Here, the diameter of each mesh hole is preferably 75 to 300 &#x3bc;m. The reason is as follows. If the diameter of the mesh hole is less than 75 &#x3bc;m, it is difficult to overlay the upper and lower mesh holes on one another. If the diameter exceeds 300 &#x3bc;m, the insulating properties of the interlayer resin insulating layers deteriorate. In addition, the distance between the mesh holes is preferably 100 to 2000 &#x3bc;m. The reason is as follows. If the distance is less than 100 &#x3bc;m, the solid layer cannot function. If the distance exceeds 2000 &#x3bc;m, the deterioration of the insulating properties of the interlayer resin insulating film occurs.

Multilayer build-up wiring board including a chip mount region

Method of manufacturing a multilayered printed circuit board

Multilayer build-up wiring board

Method of manufacturing multilayered circuit board

Mesh holes and of upper solid layers and upper solid layers are formed to overlie on one another, so that the insulating properties of interlayer resin insulating layers are not lowered. Here, the diameter of each mesh hole is preferably to 300 &mgr;m. The reason is as follows. If the diameter of the mesh hole is less than 75 &mgr;m, it is difficult to overlay the upper and lower mesh holes on one another. If the diameter exceeds 300 &mgr;m, the insulating properties of the interlayer resin insulating layers deteriorate. In addition, the distance between the mesh holes is preferably 100 to 2000 &mgr;m. The reason is as follows. If the distance is less than 100 &mgr;m, the solid layer cannot function. If the distance exceeds 2000 &mgr;m, the deterioration of the insulating properties of the interlayer resin insulating film occurs.

An opening is formed in resin by a laser beam so that a via hole is formed. Copper foil, the thickness of which is reduced to 3 &mgr;m by etching to lower the thermal conductivity, is used as a conformal mask. Therefore, an opening is formed in the resin and the number of irradiation of pulse-shape laser beam is reduced. Thus, occurence of undercut of the resin, which forms an interlayer insulating resin layer, can be prevented and the reliability of the connection of the via holes can be improved.

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Ibi-gun, Japan

Honjin En