JPS6430712A - Method for finely drilling green sheet - Google Patents

Abstract

PURPOSE:To make it possible to easily drill fine through-holes on a green sheet with simple apparatus by a method wherein through-holes of the same diameter are drilled on two sheets of metal plates at positions corresponding to each other and the green sheet is pinched between the metal plates so as to be sucked from one metal plate side in order to pierce holes, the diameter of each of which is substantially the same as that of the hole of the metal plate. CONSTITUTION:A pair of templates 1 and 2 having the same thickness are made by drilling about 1500 through-holes for making vias, which correspond to the positions and hole diameters of the through-holes of a ceramic insulating layer, from both the sides of each 100mmX100mm nickel plate. A green sheet with a thickness of 0.2mm is formed by a doctor coating method by kneading a mixture of 50pts.wt. of alumina having mean particle diameter of 3-4mum, 50pts.wt. of borosilicate glass having the same mean particle diameter as just mentioned above, 10pts.wt. of polymethyl methacrylate resin and 100pts.wt. of acetone. The green sheet 6, at four corners of which holes with larger hole diameter are made at the positions corresponding to the positioning holes of the template, is pinched between two sheets of the templates 1 and 2 and heated up to 100 deg.C so as to soften the binder resin and sucked with a vacuum pump so as to remove the portions corresponding to the holes 3 of the template in order to make a large number of holes simultaneously.