Joined structure, joining method, and joining material

Abstract

A joined structure includes: a first member; and a second member that faces the first member and that is joined to the first member via a joining layer. The joining layer includes a metal material and a solder material, apart of the metal material has at least one pore, and the solder material is located in a part of an internal area of the at least one pore. Also disclosed is a joining method that makes it possible to produce the joined structure. Further disclosed is a joining material used in the joining method. The joining method makes it possible to achieve non-pressurization sintering processes while maintaining high precise thickness of a joining layer between the first layer and the second layer based on the spacer.

What is claimed is: 
     
         1 . A joined structure, comprising:
 a first member; and   a second member that faces the first member and that is joined to the first member via a joining layer, wherein   the joining layer comprises a metal material and a solder material,   a part of the metal material is porous state, and   the solder material is located in a part of the porous state.   
     
     
         2 . The joined structure according to  claim 1 , wherein an alloy of the metal material and the solder material is present in a part of the joining layer. 
     
     
         3 . The joined structure according to  claim 1 , wherein the porous state comprises multiple pores, and an alloy of the metal material and the solder material is present in parts of the multiple pores. 
     
     
         4 . The joined structure according to  claim 1 , wherein the metal material is a sintered metal. 
     
     
         5 . The joined structure according to  claim 2 , wherein the alloy has a melting point higher than a melting point of the solder material. 
     
     
         6 . The joined structure according to  claim 1 , wherein the solder material comprises Bi or In. 
     
     
         7 . The joined structure according to  claim 2 , wherein the metal material is Ag, and the alloy at least comprises Ag and Bi, or Ag and In. 
     
     
         8 . The joined structure according to  claim 2 , wherein the solder material and/or the alloy are locally and continuously located over an area from the first member and the second member. 
     
     
         9 . A joining method, comprising:
 (i) supplying, onto a first surface of a first member, a nanometal paste at least comprising metal nanoparticles and a solvent, and a spacer;   (ii) facing a second member to the first member, and pushing said second member onto the spacer, to mount said second member over the first member;   (iii) heating a product obtained in Step (ii) at a temperature equal to or lower than a temperature where the solvent in the nanometal paste is evaporated, to cause the spacer to melt or decompose;   (iv) heating the product resulting from Step (iii) at the temperature where the solvent in the nanometal paste is evaporated; and   (v) heating the product resulting from Step (iv) at a temperature where the metal nanoparticles are sintered.   
     
     
         10 . The joining method according to  claim 9 , wherein an area between the first member and the second member is not pressurized in Steps (iii), (iv) and (v). 
     
     
         11 . The joining method according to  claim 9 , wherein the spacer is a solder material. 
     
     
         12 . The joining method according to  claim 11 , wherein the solder material comprises Bi or In. 
     
     
         13 . The joining method according to  claim 9 , wherein the spacer has a spherical shape, a columnar shape, a wire shape, or a foil shape. 
     
     
         14 . The joining method according to  claim 9 , wherein, in Step (i), the nanometal paste comprising the spacer in advance is supplied onto the first surface of the first member. 
     
     
         15 . A nanometal paste joining material, comprising metal nanoparticles, a solvent, and a spacer that is melted or decomposed at a temperature lower than a boiling point of the solvent. 
     
     
         16 . The nanometal paste joining material according to  claim 15 , wherein the spacer is a solder material. 
     
     
         17 . The nanometal paste joining material according to  claim 16 , wherein the solder material comprises Bi or In.