Drill and method of producing printed wiring board

Abstract

A printed wiring board manufacturing method for forming a hole penetrating through a board having an electric conductor layer and forming the electric conductor layer in the hole to make electrical connection, the method including forming a hole that penetrates through the board in accordance with a drill featured in that a blade portion is formed at a distal end and a groove is formed by one stripe, and an occupying rate of a metal at a proximal end of the blade tip of the body is in the range of 40% to 80%; and a curvature radius in an axially vertical direction of a deepest portion of the groove is in the range of 1.50 to 3.50 mm, forming an electric conductor layer in a hole, and forming an electric conductor circuit on a top layer of the board.

1 . A printed wiring board manufacturing method for forming a hole penetrating through a board having an electric conductor layer and forming the electric conductor layer in the hole to make electrical connection, the method comprising:
 forming a hole that penetrates through the board in accordance with a drill featured in that a blade portion is formed at a distal end and a groove is formed by one stripe, and an occupying rate of a metal at a proximal end of the blade tip of the body is in the range of 40% to 80%; and a curvature radius in an axially vertical direction of a deepest portion of the groove is in the range of 1.50 to 3.50 mm;   forming an electric conductor layer in a hole; and   forming an electric conductor circuit on a top layer of the board.   
     
     
         2 . The printed wiring board manufacturing method according to  claim 1 ,
 wherein the step of carrying out desmear processing is carried out after the hole forming step.   
     
     
         3 . The printed wiring board manufacturing method according to  claim 1 ,
 wherein a distal end diameter of a drill in the hole forming step is equal to or smaller than 300 microns.   
     
     
         4 . The printed wiring board manufacturing method according to  claim 1 ,
 wherein a torsion angle of the drill is in the range of 30 degrees to 50 degrees.   
     
     
         5 . A printed wiring board manufacturing method for forming a hole penetrating through a board having an electric conductor layer and forming the electric conductor layer in the hole to make electrical connection, the method comprising:
 forming an opening that penetrates a board by means of a drill featured in that a shaving discharge groove is formed in a one-stripe shape at a body and a torsion angle of the shaving discharge groove is in the range of 30 degrees to 50 degrees.   forming an electric conductor layer in a hole; and   forming an electric conductor circuit in a top layer of the substrate.   
     
     
         6 . The printed wiring board manufacturing method as claimed in  claim 5 ,
 wherein, in the drill, an occupying rate of a metal at the proximal end of the blade tip of the body is in the range of 40% to 80%, and a curvature radius in an axially vertical direction of a deepest portion of a groove at the proximal end is in the range of 1.50 mm to 3.50 mm.   
     
     
         7 . The printed wiring board manufacturing method according to  claim 2 ,
 wherein a distal end diameter of a drill in the hole forming step is equal to or smaller than 300 microns.