Method of manufacturing component-embedded printed wiring board

Abstract

A component-embedded printed wiring board (PWB) is disclosed. This PWB includes (a) a fluid-resin embedding section formed at a location corresponding to electronic components such that the embedding section covers the electronic components, (b) a resin flow-speed accelerator placed in parallel with a top face of a circuit board and surrounding the embedding section, and (c) bonding resin placed at least between the accelerator and the circuit board. The fluid resin embedding section is filled up with the same resin as the bonding resin. This structure allows the accelerator to compress the resin with pressure applied to the PWB, so that the resin tends to flow along the circuit board. As a result, the fluid-resin embedding section is thoroughly filled up with the resin without leaving any air, and the reliable PWB is thus obtainable.

1 . A method of manufacturing a component-embedded printed wiring board in which a plurality of electronic components are embedded, the method comprising the steps of:
 mounting the plurality of electronic components on land patterns on a top face of a circuit board and fixing electrodes of the electronic components on the land patterns using a coupling and fixing member;   after the mounting and fixing step, hanging a resin by disposing the resin on the circuit board such that spaces are formed between the resin and the circuit board at least at peripheries of the electronic components; and   after the hanging step, unifying the resin and the circuit board together by heating and pressing,   wherein the resin is a thermosetting resin having no fluidity within a first temperature range, and has a fluidity in a second temperature range higher than the first range, and is hardened in a third temperature range higher than the second range, and   wherein the unifying step includes   (a-1) a first heating step for heating the resin to the second temperature range and softening the resin, and then   (a-2) forcible flow-in step which forcibly charges the resin into a space formed between the electronic components and the circuit board by compressing the resin before the resin is heated to the third temperature range, and then   (a-3) a second heating step for heating the resin to the third temperature range,   wherein the temperature rises slower in the forcible flow-in step than in the first heating step.   
   
   
       2 . The method of manufacturing a component-embedded printed wiring board of  claim 1 , wherein the temperature rises slower in the second heating step than in the first heating step. 
   
   
       3 . The method of manufacturing a component-embedded printed wiring board of  claim 1 , wherein the resin is in a liquid phase in the hanging step. 
   
   
       4 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a temperature of the resin is set lower than a temperature at which a viscosity of the resin becomes a minimum value, and the thermosetting resin is charged into the space by decompressing the resin and the circuit board at the lower temperature, in the forcible flow-in step. 
   
   
       5 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a temperature of the resin is set lower than a temperature at which a viscosity of the resin becomes a minimum value at least by an amount of a temperature rise value when the resin is charged into the space, in the forcible flow-in step. 
   
   
       6 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the resin temperature when the resin is charged into the space is set lower than a temperature at which a viscosity of the resin becomes a minimum value in the forcible flow-in step. 
   
   
       7 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the coupling and fixing member is a solder, and
 wherein a temperature of the resin is set lower than a temperature of a melting temperature of the solder at least by an amount of a temperature rise value of the resin when the resin is charged into the space, in the forcible flow-in step.   
   
   
       8 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the coupling and fixing member is a solder, and
 wherein the resin temperature when the resin is charged into the space is set lower than a melting temperature of the solder in the forcible flow-in step.   
   
   
       9 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a pressure applied in the forcible flow-in step is set small enough for a viscosity of the resin not to rise due to a temperature rise caused by friction between the resin and the electronic components or the circuit board when the resin flows into the space. 
   
   
       10 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the coupling and fixing member is a solder, and
 wherein a pressure applied in the forcible flow-in step is set small enough for a temperature of the resin not to exceed a melting temperature of the solder due to a temperature rise caused by friction between the resin and the electronic components or the circuit board when the resin flows into the space.   
   
   
       11 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the resin is charged into the space in the forcible flow-in step, and a viscosity of the resin decreases due to a heating caused by the charging. 
   
   
       12 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a compression pressure is maintained in the forcible flow-in step. 
   
   
       13 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a temperature characteristic of the resin includes an overshooting temperature range in the forcible flow-in step. 
   
   
       14 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a maximum temperature of the overshooting temperature range is set to be lower than a temperature at which a viscosity of the resin becomes a minimum value by an amount of a temperature rise value due to a friction or a pressure decrease when the resin is charged into the space. 
   
   
       15 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein a temperature of the resin is maintained in the forcible flow-in step. 
   
   
       16 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the circuit board is hanged in the hanging step. 
   
   
       17 . The method of manufacturing a component-embedded printed wiring board of  claim 3 , wherein the resin is prevented from flowing out to an outside. 
   
   
       18 . A method of manufacturing a component-embedded printed wiring board in which a plurality of electronic components are embedded, the method comprising the steps of:
 mounting the plurality of electronic components on land patterns on a top face of a circuit board and fixing electrodes of the electronic components on the land patterns using a coupling and fixing member;   after the mounting and fixing step, hanging a resin by disposing the resin on the circuit board such that spaces are formed between the resin and the circuit board at least at peripheries of the electronic components;   after the hanging step, decompressing by sucking an air in the spaces and making at least the resin to touch a top faces of the electronic components; and   after the decompression step, unifying the resin and the circuit board together by heating and pressing,   wherein the resin is a thermosetting resin having fluidity within a first temperature range, and hardens in a second temperature range higher than the first range, and   wherein the unifying step includes   (a-1) forcible flow-in step which forcibly charges the resin into a space formed between the electronic components and the circuit board by compressing the resin within the first temperature range, and then   (a-3) a second heating step for heating the resin to the second temperature range.   
   
   
       19 . The method of manufacturing a component-embedded printed wiring board of  claim 18 , wherein the resin is in a liquid phase in the hanging step. 
   
   
       20 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a temperature of the resin is set lower than a temperature at which a viscosity of the resin becomes a minimum value, and the thermosetting resin is charged into the space by decompressing the resin and the circuit board at the lower temperature, in the forcible flow-in step. 
   
   
       21 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a temperature of the resin is set lower than a temperature at which a viscosity of the resin becomes a minimum value at least by an amount of a temperature rise value when the resin is charged into the space, in the forcible flow-in step. 
   
   
       22 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the resin temperature when the resin is charged into the space is set lower than a temperature at which a viscosity of the resin becomes a minimum value in the forcible flow-in step. 
   
   
       23 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the coupling and fixing member is a solder, and
 wherein a temperature of the resin is set lower than a temperature of a melting temperature of the solder at least by an amount of a temperature rise value of the resin when the resin is charged into the space, in the forcible flow-in step.   
   
   
       24 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the coupling and fixing member is a solder, and
 wherein the resin temperature when the resin is charged into the space is set lower than a melting temperature of the solder in the forcible flow-in step.   
   
   
       25 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a pressure applied in the forcible flow-in step is set small enough for a viscosity of the resin not to rise due to a temperature rise caused by friction between the resin and the electronic components or the circuit board when the resin flows into the space. 
   
   
       26 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the coupling and fixing member is a solder, and
 wherein a pressure applied in the forcible flow-in step is set small enough for a temperature of the resin not to exceed a melting temperature of the solder due to a temperature rise caused by friction between the resin and the electronic components or the circuit board when the resin flows into the space.   
   
   
       27 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the resin is charged into the space in the forcible flow-in step, and a viscosity of the resin decreases due to a heating caused by the charging. 
   
   
       28 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a compression pressure is maintained in the forcible flow-in step. 
   
   
       29 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a temperature characteristic of the resin includes an overshooting temperature range in the forcible flow-in step. 
   
   
       30 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a maximum temperature of the overshooting temperature range is set to be lower than a temperature at which a viscosity of the resin becomes a minimum value by an amount of a temperature rise value due to a friction or a pressure decrease when the resin is charged into the space. 
   
   
       31 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein a temperature of the resin is maintained in the forcible flow-in step. 
   
   
       32 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the circuit board is hanged in the hanging step. 
   
   
       33 . The method of manufacturing a component-embedded printed wiring board of  claim 19 , wherein the resin is prevented from flowing out to an outside.