Method of manufacturing reuse paste, reuse paste and method of manufacturing circuit board using reuse paste

A reuse paste obtained by a method of manufacturing a reuse paste,

• wherein the method comprises:
• preparing a fiber piece housing paste that includes a conductive paste including a conductive particle, resin and a latent curing agent, and a fiber piece dropping off from a prepreg used for manufacturing a circuit board;
• producing a filtered recovery paste by filtering the fiber piece housing paste, which remains in a paste state, by using a filter;
• and
• producing reuse paste by adding at least one of a solvent, resin, and a paste having a different composition from that of the filtered recovery paste into the filtered recovery paste.

A method of manufacturing a circuit board, the method comprising:

• attaching a first protective film to a surface of a first prepreg;
• forming a first hole in the first prepreg through the first protective film;
• applying a conductive paste including a conductive particle, resin and a latent curing agent onto the first protective film;
• filling a part of the conductive paste into the first hole;
• gathering a plurality of the conductive pastes which have not been filled into the first hole for recovering them as a fiber piece housing paste;
• producing a filtered recovery paste by filtering the fiber piece housing paste, which remains in a paste state, by using a filter;
• producing a reuse paste by adding at least one of a solvent, resin, and a paste having a different composition from that of the filtered recovery paste into the filtered recovery paste;
• attaching a second protective film to a surface of a second prepreg;
• forming a second hole in the second prepreg through the second protective film;
• filling the reuse paste into the second hole;
• peeling the second protective film so as to form a protruded portion made of the reuse paste on the surface of the second prepreg;
• disposing a metal foil on both surfaces of the second prepreg, and pressurizing the second prepreg from outside of the metal foil;
• curing the second prepreg and the reuse paste by heating the second prepreg;
• and
• processing the metal foil into a wiring pattern.

A method of manufacturing a circuit board, the method comprising:

• preparing a fiber piece housing paste including a conductive paste that includes a conductive particle, resin, and a latent curing agent, and a fiber piece dropping off from a first prepreg;
• producing a filtered recovery paste by filtering the fiber piece housing paste, which remains in a paste state, by using a filter;
• producing a reuse paste by adding at least one of a solvent, resin, and a paste having a different composition from that of the filtered recovery paste into the filtered recovery paste;
• attaching a second protective film to a surface of a second prepreg;
• forming a second hole in the second prepreg through the second protective film;
• filling the reuse paste into the second hole;
• peeling the second protective film so as to form a protruded portion made of the reuse paste on the surface of the second prepreg;
• disposing a metal foil on both surfaces of the second prepreg, and pressurizing the second prepreg from outside of the metal foil;
• curing the second prepreg and the reuse paste by heating the second prepreg;
• and
• processing the metal foil into a wiring pattern.