Wafer or circuit board and joining structure of wafer or circuit board

Abstract

A wafer (or a circuit board), which is used to perform three-dimensional mounting, has protrusion 20 which is provided in low melting point metal 15 for electrically connecting mutually joined wafers 61 and 62, and which defines an interval between mutually joined wafers 61 and 62 without being deformed at the time when low melting point metal 15 is melted. A joining structure of wafers 61 and 62 is manufactured by using wafers 61 and 62, at least one of which has protrusion 20. In the manufactured joining structure of wafers 61 and 62, wafers 61 and 62 are electrically connected to each other by low melting point metal 15, and protrusion 20, which defines the interval between wafers 61 and 62 without being deformed at the time when low melting point metal 15 is melted, is provided in low melting point metal 15.

What is claimed is: 
     
         1 . A device, comprising:
 a first substrate;   a first conductor penetrating the first substrate;   a first conductive film disposed on a first surface of the first substrate and electrically connected to the first conductor;   a first protrusion disposed on the first conductive film; and   a low-melting point metal disposed over the first conductive film,   wherein the first protrusion has a melting point higher than a melting point of the low-melting point metal.   
     
     
         2 . The device according to  claim 1 , further comprising a first metal, wherein
 the first metal covers an upper surface and a side surface of the first protrusion and a part of the first conductive film,   the first metal has a first top surface and a second top surface, and   the first top surface is higher than the second top surface from the first conductive film.   
     
     
         3 . The device according to  claim 2 , wherein the first metal has a melting point higher than the melting point of the low—melting point metal. 
     
     
         4 . The device according to  claim 1 , further comprising a second conductive film disposed on a second surface of the first substrate, the second surface being opposite to the first surface, and the second conductive film being electrically connected to the first conductor. 
     
     
         5 . The device according to  claim 1 , wherein the first conductor comprises at least one of a poly-silicon and a metal. 
     
     
         6 . The device according to  claim 1 , wherein a diameter of the first conductor is substantially equal or smaller than 50 μm and a depth of the first conductor is substantially equal or smaller than 100 μm. 
     
     
         7 . The device according to  claim 1 , wherein the first conductive film comprises titanium and copper. 
     
     
         8 . The device according to  claim 4 , further comprising a second metal on the second conductive film. 
     
     
         9 . The device according to  claim 8 , further comprising a first insulation film disposed on the second surface of the first substrate, a part of the first insulation film being covered with the second metal. 
     
     
         10 . The device according to  claim 1 , further comprising a second substrate, and a second conductive film disposed on a first surface of the second substrate,
 wherein the first and second conductive films are electrically connected and the low melting point metal is disposed between the first and second conductive films.   
     
     
         11 . The device according to  claim 10 , further comprising a second conductor penetrating the second substrate and electrically connected to the second conductive film. 
     
     
         12 . The device according to  claim 10 , further comprising:
 a first metal covering an upper surface and a side surface of the first protrusion and a part of the first conductive film; and   a second metal on the second conductive film,   wherein the first and the second metals are electrically connected, the first and the second metals are disposed between the first and second conductive films, and the low-melting point metal is disposed between the first metal and the second metal.   
     
     
         13 . The device according to  claim 11 , further comprising:
 a third conductive film disposed on a second surface of the first substrate, the second surface being opposite to the first surface of the first substrate, and the third conductive film being electrically connected to the first conductor; and   a fourth conductive film disposed on a second surface of the second substrate, the second surface of the second substrate being opposite to the first surface of the second substrate, and the fourth conductive film being electrically connected to the second conductor.   
     
     
         14 . The device according to  claim 13 , further comprising a fourth metal on the fourth conductive film. 
     
     
         15 . The device according to  claim 12 , wherein the first metal has a melting point higher than the melting point of the low-melting point metal and the second metal has a melting point higher than the melting point of the low-melting point metal. 
     
     
         16 . The device according to  claim 11 , wherein an each diameter of the first and the second conductors is substantially equal or smaller than 50 μm, and a depth of each of the first and the second conductors is substantially equal or smaller than 100 μm. 
     
     
         17 . The device according to  claim 1 , further comprising:
 a second substrate;   a second conductor penetrating the second substrate;   a second conductive film disposed on a first surface of the second substrate and electrically connected to the second conductor; and a second protrusion disposed on the second conductive film,   wherein the first and second conductive films are electrically connected and the low-melting point metal is disposed between the first and second conductive films, the low-melting point metal is disposed over the second conductive film, and the second protrusion has a melting point higher than the melting point of the low-melting metal.   
     
     
         18 . The device according to  claim 17 , further comprising:
 a first metal covering an upper surface and a side surface of the first protrusion and a part of the first conductive film; and   a second metal covering an upper surface and a side surface of the second protrusion and part of the second conductive film,   wherein the first and the second metals are electrically connected and are disposed between the first and second conductive films, a part of the first metal and a part of the second metal are disposed between the first and second protrusions, and the low-melting point metal is disposed between the first and the second metals.   
     
     
         19 . The device according to  claim 18 , wherein
 the first metal has a first top surface and a second top surface, the first top surface being higher than the second top surface from the first conductive film, and   the second metal has a third top surface and a fourth top surface, the third top surface being higher than the fourth top surface from the second conductive film.   
     
     
         20 . The device according to  claim 17 , further comprising:
 a third conductive film disposed on a second surface of the first substrate, the second surface of the first substrate being opposite to the first surface of the first substrate, and the third conductive film being electrically connected to the first conductor; and   a fourth conductive film disposed on a second surface of the second substrate, the second surface of the second substrate being opposite of the first surface of the second substrate, and the fourth conductive film being electrically connected to the second conductor.   
     
     
         21 . The device according to  claim 20 , further comprising a fourth metal on the fourth conductive film. 
     
     
         22 . The device according to  claim 18 , wherein the second metal has a melting point higher than the melting point of the low-melting point metal.