Bump-equipped electronic component and method for manufacturing bump-equipped electronic component

Abstract

A bump-equipped electronic component includes a circuit substrate and first and second bumps which are disposed on a principal surface of the circuit substrate and have different cross-sectional areas in a direction parallel or substantially parallel to the principal surface. One of the first and second bumps having a smaller cross-sectional area includes a height adjustment layer disposed in a direction perpendicular or substantially perpendicular to the principal surface.

What is claimed is: 
     
         1 . A method for manufacturing a bump-equipped electronic component, the method comprising:
 a step of forming first and second bumps primarily composed of Cu, on a principal surface of a circuit substrate, the first and second bumps having different cross-sectional areas in a direction parallel or substantially parallel to the principal surface; wherein   the step of forming the first and second bumps includes a step of forming a height adjustment layer in a direction perpendicular or substantially perpendicular to the principal surface when one of the first and second bumps having a smaller cross-sectional area is formed.   
     
     
         2 . The method according to  claim 1 , wherein the step of forming the first and second bumps includes a step of forming the height adjustment layer on each of the first and second bumps. 
     
     
         3 . The method according to  claim 1 , wherein the height adjustment layer is disposed on a top end of the bump provided with the height adjustment layer. 
     
     
         4 . The method according to  claim 1 , wherein the height adjustment layer is disposed in a central portion in the perpendicular or substantially perpendicular direction of the bump provided with the height adjustment layer. 
     
     
         5 . The method according to  claim 1 , wherein the height adjustment layer and the bump provided with the height adjustment layer have the same cross-sectional area in the direction parallel or substantially parallel to the principal surface. 
     
     
         6 . The method according to  claim 1 , wherein the height adjustment layer has a resistivity that is different from a resistivity of a main material from which the bump provided with the height adjustment layer is composed. 
     
     
         7 . The method according to  claim 1 , wherein each of the first and second bumps includes a solder layer disposed at a top end thereof, and the solder layer of one of the first and second bumps having a larger cross-sectional area in the direction parallel or substantially parallel to the principal surface has a higher melting point than that of the solder layer of the bump having a smaller cross-sectional area in the direction parallel or substantially parallel to the principal surface. 
     
     
         8 . The method according to  claim 2 , wherein the height adjustment layer is disposed on a top end of each of the first and second bumps. 
     
     
         9 . The method according to  claim 2 , wherein the height adjustment layer is disposed in a central portion in the perpendicular or substantially perpendicular direction of each of the first and second bumps. 
     
     
         10 . The method according to  claim 2 , wherein the height adjustment layer and the respective bump of the first and second bumps provided with the height adjustment layer have the same cross-sectional area in the direction parallel or substantially parallel to the principal surface. 
     
     
         11 . The method according to  claim 2 , wherein the height adjustment layer has a resistivity that is different from a resistivity of a main material from which the respective bump of the first and second bumps provided with the height adjustment layer is composed. 
     
     
         12 . The method according to  claim 2 , wherein each of the first and second bumps includes a solder layer disposed at a top end thereof, and the solder layer of one of the first and second bumps having a larger cross-sectional area in the direction parallel or substantially parallel to the principal surface has a higher melting point than that of the solder layer of the bump having a smaller cross-sectional area in the direction parallel or substantially parallel to the principal surface.