Semiconductor device and method of manufacturing the same

Abstract

A semiconductor device including a semiconductor substrate having oppositely facing first and second surfaces, the first surface being an active surface and provided with an electronic element thereon, a pad electrode to be connected to the electronic element in a peripheral portion of the electronic element on the active surface, a first opening extending from the second surface toward the pad electrode so as not to reach the first surface of the semiconductor substrate, a second opening formed to reach the pad electrode from a bottom surface of the first opening and having a diameter smaller than that of the first opening, an insulating layer formed to cover sidewall surfaces of the first opening and the second opening, and a conductive layer formed, inside of the insulating layer, to cover at least an inner wall surface of the insulating layer and a bottom surface of the second opening.

1 . A semiconductor device comprising:
 a semiconductor substrate having first and second surfaces opposite each other, the first surface being an active surface by provided with an electronic element thereon;   a pad electrode formed to be connected to the electronic element in a peripheral portion of the electronic element on the active surface;   a first opening extending from the second surface of the semiconductor substrate toward the pad electrode so as not to reach the first surface of the semiconductor substrate;   a second opening, formed to reach the pad electrode from a bottom surface of the first opening, having a diameter smaller than that of the first opening;   an insulating layer formed to cover sidewall surfaces of the first opening and the second opening; and   a conductive layer formed, inside of the insulating layer, to cover at least an inner wall surface of the insulating layer and a bottom surface of the second opening.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the second opening has a diameter of 0.7 times or less that of the first opening. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the first opening has a depth of 0.5 times or more and 0.9 times or less a thickness of the semiconductor substrate. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein the insulating layer is formed such that a portion covering the sidewall surface of the first opening is thicker than a portion covering the sidewall surface of the second opening. 
     
     
         5 . The semiconductor device according to  claim 1 , further comprising:
 a package substrate opposed to the active surface of the semiconductor substrate; and   a sealing resin layer formed in a gap between the peripheral portion of the electronic element on the semiconductor substrate and the package substrate to air-tightly seal the electronic element.   
     
     
         6 . The semiconductor device according to  claim 1 , wherein the electronic element is a solid-state image sensor.