Metal paste, bonding method and method for producing bonded body

Abstract

A metal paste for low temperature bonding at temperatures 600° C. or lower, the metal paste comprising: a metal particle with an average particle size of 1 to 100 μm; a metal nanoparticle with an average particle size of 1 to 500 nm; a stress relieving material; and a dispersion medium to disperse the metal particle, metal nanoparticle, and the stress relieving material.

1 . A metal paste for low temperature bonding at temperatures 600° C. or lower, the metal paste comprising:
 a metal particle with an average particle size of 1 to 100 μm; 
 a metal nanoparticle with an average particle size of 1 to 500 nm; 
 a stress relieving material; and 
 a dispersion medium to disperse the metal particle, metal nanoparticle, and the stress relieving material. 
 
     
     
         2 . The metal paste according to  claim 1 , wherein the metal particle and the metal nanoparticles have different metal species from each other. 
     
     
         3 . The metal paste according to  claim 1 , wherein the metal particle is a copper particle. 
     
     
         4 . The metal paste according to  claim 3 , wherein the copper particle have a nanostructure on the surface. 
     
     
         5 . The metal paste according to  claim 1 , wherein the metal nanoparticle include one or more particles selected from the group of a gold nanoparticle, a silver nanoparticle, and a copper nanoparticle. 
     
     
         6 . The metal paste according to  claim 1 , wherein the average particle size of the metal nanoparticle is between 1 and 100 nm. 
     
     
         7 . The metal paste according to  claim 1 , wherein the metal nanoparticles are contained in 0.01 to 60 parts by mass in 100 parts by mass of the metal paste. 
     
     
         8 . The metal paste according to  claim 1 , wherein the average particle size of the stress relieving material is between 0.01 to 100 μm. 
     
     
         9 . The metal paste according to  claim 1 , wherein the stress relieving material is one or more inorganic materials selected from the group of tungsten, alumina, aluminum nitride, and glass. 
     
     
         10 . A bonding method comprising:
 preparing a laminate in which the metal paste according to  claim 1  is disposed between a first member and a second member; and heating the laminate to sinter the metal paste,   wherein the temperature at which the metal paste is sintered is 600° C. or lower.   
     
     
         11 . A method for producing a bonded body comprising:
 preparing a laminate in which the metal paste according to  claim 1  is disposed between a first member and a second member; and heating the laminate to sinter the metal paste, whereby the first member and the second member are bonded,   wherein the temperature at which the metal paste is sintered is 600° C. or lower.