Method of manufacturing multilayer printed circuit board

Abstract

In a method of manufacturing a multilayer printed circuit board, a plurality of insulating substrates each having a first surface and a second surface is prepared. A circuit pattern is formed on each of the first surfaces of the insulating substrates. A plurality of via holes is provided so as to extend through respective ones of the insulating substrates from a side of the second surfaces in such a manner that the via holes reach corresponding ones of the circuit patterns. Ones of a plurality of sintered bodies made of conductive particles is inserted into corresponding ones of the via holes and is fixed in the via holes. The insulating substrates are stacked so that the circuit patterns are electrically coupled through the sintered bodies.

1 . A method of manufacturing a multilayer printed circuit board, comprising:
 preparing a plurality of insulating substrates each having a first surface and a second surface;   forming a circuit pattern on each of the first surfaces of the plurality of insulating substrates to form a plurality of the circuit patterns;   providing a plurality of via holes that extend through respective ones of the plurality of insulating substrates from a side of the second surfaces such that the plurality of via holes reaches corresponding ones of the plurality of the circuit patterns;   inserting ones of a plurality of sintered bodies into corresponding ones of the plurality of via holes, the plurality of sintered bodies formed by sintering a plurality of aggregation of conductive particles;   fixing the plurality of sintered bodies into the plurality of via holes; and   stacking the plurality of insulating substrates and electrically coupling the plurality of circuit patterns through the plurality of sintered bodies.   
   
   
       2 . The method according to  claim 1 , wherein
 the conductive particles include silver particles and tin particles.   
   
   
       3 . The method according to  claim 2 , wherein
 a tin content of the whole conductive particles is in a range from about 20% to about 80% by weight.   
   
   
       4 . The method according to  claim 3 , wherein
 the tin content of the whole conductive particles is in a range from about 30% to about 50% by weight.   
   
   
       5 . The method according to  claim 1 , wherein
 a ratio of a maximum dimension of each of the plurality of sintered bodies to a thickness of each of the plurality of insulating substrates is in a range from about 1 to about 1.4.   
   
   
       6 . The method according to  claim 5 , wherein
 the ratio of the maximum dimension of the each of the plurality of sintered bodies to the thickness of the each of the plurality of insulating substrates is in a range from about 1 to about 1.3.   
   
   
       7 . The method according to  claim 1 , wherein
 each of the plurality of sintered bodies is deformed when the plurality of sintered bodies is fixed into the plurality of via holes.   
   
   
       8 . The method according to  claim 7 , wherein:
 the ones of the plurality of sintered bodies and the corresponding ones of the plurality of via holes have a clearance therebetween when the ones of the plurality of sintered bodies is inserted into the corresponding ones of the plurality of via holes; and   the deformation amount of the plurality of sintered bodies is let into the clearance when the plurality of sintered bodies is fixed into the plurality of via holes.   
   
   
       9 . The method according to  claim 1 , wherein a manufacturing method of the plurality of sintered bodies includes:
 mixing the conductive particles that includes silver particles and tin particles with a solvent to provide a paste;   forming the paste into a predetermined shape by using a mask;   sintering the paste; and   rinsing the sintered paste for removing a carbide.   
   
   
       10 . A method of manufacturing a multilayer printed circuit board, comprising:
 preparing a plurality of insulating substrates each having a first surface and a second surface;   forming a circuit pattern on each of the first surfaces of the plurality of insulating substrates to form the plurality of circuit patterns;   providing a plurality of via holes that extend through respective ones of the plurality of insulating substrates from a side of the second surfaces such that the plurality of via holes reaches corresponding ones of the plurality of the circuit patterns;   inserting ones of a plurality of sintered bodies into corresponding ones of the plurality of via holes, the plurality of sintered bodies formed by sintering a plurality of aggregation of conductive particles, the plurality of sintered bodies having a height that is less than a depth of the plurality of via holes;   stacking the plurality of insulating substrates in such a manner that ones of the plurality of the circuit patterns is fitted into corresponding ones of the plurality of via holes; and   pressing the stacked insulating substrates during heating so that the ones of the plurality of the circuit patterns comes in contact with corresponding ones of the plurality of the sintered bodies in the corresponding via holes and the plurality of circuit patterns is electrically coupled through the plurality of sintered bodies.   
   
   
       11 . The method according to  claim 10 , wherein
 the conductive particles include silver particles and tin particles.   
   
   
       12 . The method according to  claim 11 , wherein
 a tin content of the whole conductive particles is in a range from about 20% to about 80% by weight.   
   
   
       13 . The method according to  claim 12 , wherein
 the tin content of the whole conductive particles is in a range from about 30% to about 50% by weight.   
   
   
       14 . The method according to  claim 10 , wherein:
 an exposed surface of the ones of the plurality of sintered bodies is positioned at a predetermined distance from an open end of the corresponding ones of the plurality of via holes when the ones of the plurality of sintered bodies is inserted into the corresponding ones of the plurality of via holes; and   the predetermined distance is less than or equal to a thickness of the plurality of the circuit patterns.   
   
   
       15 . The method according to  claim 10 , wherein a manufacturing method of the plurality of sintered bodies includes:
 mixing the conductive particles that includes silver particles and tin particles with a solvent to provide a paste;   forming the paste into a predetermined shape by using a mask;   sintering the paste; and   rinsing the sintered paste for removing a carbide.