Through electrode, spacer provided with the through electrode, and method of manufacturing the same

Abstract

A through electrode that offers excellent performance and can be manufactured through a simple process is to be provided. In a silicon spacer including a silicon substrate, an insulative thick film is provided so as to be in contact with a surface of the silicon substrate and a side wall of a through hole penetrating the silicon substrate. An upper surface of a through plug is retreated to a lower level than an interface between the silicon substrate and the insulative thick film, thus to define a height gap. A first bump is then formed, which is connected to the retreated surface of the through plug and has a larger diameter than that of the through plug at the upper surface of the insulative thick film.

1 . A through electrode comprising: 
 a silicon substrate provided with a through hole;    an insulating protective film formed on a surface of said silicon substrate with an opening connecting with said through hole;    a through plug formed by embedding a conductive material in said through hole; and    a bump connected to said through plug;    wherein said bump is connected to said through plug inside said through hole, and a portion of said bump located outside said through hole has a larger diameter than that of a portion of said bump located inside said through hole.    
     
     
         2 . The through electrode according to  claim 1 , wherein a larger-diameter portion of said bump is in contact with said insulating protective film.  
     
     
         3 . The through electrode according to  claim 1 , further comprising a side wall insulating film formed so as to cover a side wall of said through plug.  
     
     
         4 . The through electrode according to  claim 3 , wherein said side wall insulating film and said insulating protective film are continuously and integrally formed.  
     
     
         5 . The through electrode according to  claim 1 , wherein said through plug includes a barrier film covering a side wall inside said through hole, and a metal film around covered by said barrier film.  
     
     
         6 . A silicon spacer comprising a silicon substrate provided with said through electrodes according to  claim 1 .  
     
     
         7 . A method of manufacturing a through electrode, comprising: 
 forming a hole on one surface of a silicon substrate;    forming an insulating film that covers said surface and an inner wall of said hole;    forming a conductive film so as to fill said hole;    performing polishing or etching back on said conductive film so as to remove a portion of said conductive film formed outside said hole for exposing said insulating film, and to retreat a surface of said conductive film into an inner level of said silicon substrate than the surface thereof, for forming a conductive plug and a recessed portion;    growing a metal film on a retreated surface of said conductive plug thus to fill said recessed portion and to further form a bump having a larger diameter outside said hole than that of a portion of said bump located inside said hole; and    polishing another surface of said silicon substrate for exposing said conductive plug, thus to form a through electrode.    
     
     
         8 . The method according to  claim 7 , wherein said forming said bump includes forming a barrier metal film on the surface of said conductive plug and a side wall of said recessed portion, and growing said metal film utilizing said barrier metal film as a base.  
     
     
         9 . The method according to  claim 7 , comprising, after said step of forming said conductive plug: 
 selectively removing a portion of said silicon substrate from said another surface thereof opposite to said one surface thus to expose a surface of said conductive plug; and    growing another metal film on an exposed surface of said conductive plug, thus to form a bump on the rear surface.    
     
     
         10 . The method according to  claim 7 , comprising, after said forming said through electrode: 
 growing another metal film on an exposed surface of said conductive plug, thus to form a bump on the rear surface.    
     
     
         11 . The method according to  claim 7 , wherein said forming said insulating film includes forming a silicon oxide film on said one surface of said silicon substrate.  
     
     
         12 . The method according to  claim 7 , comprising forming a barrier film on said one surface of said silicon substrate provided with said hole, after said forming said insulating film and before said forming said conductive film.