| abstract |
A liquid thermosetting resin composition comprises (A) an epoxy resin, (B) a curing catalyst, and (C) filler, which is characterized by exhibiting a viscosity of 1500 dPa.s or below at 25 DEG C, a gel time of 300 seconds or above at a temperature at which the composition exhibits a melt viscosity of 10 dPa.s or below, and a gel time of 600 seconds or below at 130 DEG C. In producing a printed wiring board by forming an interlayer dielectric layer of a resin and a conductive circuit on the surface of a wiring substrate having a conductive circuit pattern including holes, the holes are plugged by filling the holes with the above composition, pre-curing the resulting composition by heating, abrading and removing the protrusions of the composition from the surface, and curing the remaining composition completely by additional heating. Thus, the via holes or through holes of a printed wiring board can be plugged with good workability. |