Semiconductor device, method of manufacturing semiconductor device, and solid-state image sensor

Abstract

To suppress variation in transistor characteristics due to charging damage to relieve restrictions on design necessary for avoiding the charging damage and improve the degree of freedom in design for increasing semiconductor integration. A semiconductor device includes a vertical electrode formed in a vertical hole extending from an opening portion toward a portion to be connected in a thickness direction of a base, and having a structure in which a barrier metal film and a conductive material are stacked sequentially from a side close to an insulating film exposed to the vertical hole, and a low-resistance film provided to lie between the barrier metal film and the insulating film except a vicinity of the portion to be connected, and having a lower resistance value than a resistance value of the insulating film.

1 . A semiconductor device comprising:
 a vertical electrode formed in a vertical hole extending from an opening portion toward a portion to be connected along a thickness direction of a base, and having a structure in which a barrier metal film and a conductive material are stacked sequentially from a side close to a first insulating film exposed to the vertical hole; and   a low-resistance film provided to lie between the barrier metal film and the first insulating film except a vicinity of the portion to be connected, and having a lower resistance value than a resistance value of the first insulating film.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the low-resistance film is configured by at least one of Ti, TiN, Ta, TaN, Zr, ZrN, Hf, HfN, Ru, Co, W, WN, Mn, MnN, Al, Sn, Zn, Si, Ge, Ga or SiN. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein
 the first insulating film and the barrier metal film have an extending portion extending along a field portion of the base, and   the low-resistance film is also provided to lie between the first insulating film and the barrier metal film along the field portion of the base.   
     
     
         4 . The semiconductor device according to  claim 1 , wherein
 the first insulating film and the barrier metal film have an extending portion extending along a field portion of the base, and   the low-resistance film is not provided between the first insulating film and the barrier metal film running along the field portion of the base.   
     
     
         5 . The semiconductor device according to  claim 1 , wherein
 a film thickness of the low-resistance film is thicker in a portion closer to an opening of the vertical hole in a depth direction of the vertical hole.   
     
     
         6 . The semiconductor device according to  claim 1 , wherein
 a film thickness of the low-resistance film is substantially uniform in a depth direction of the vertical hole.   
     
     
         7 . The semiconductor device according to  claim 1 , wherein
 an end portion of the low-resistance film, the end portion being close to the portion to be connected, does not reach a second insulating film stacked on a side surface of the portion to be connected, the side surface being on a side of the opening portion.   
     
     
         8 . The semiconductor device according to  claim 1 , wherein
 an end portion of the low-resistance film, the end portion being close to the portion to be connected, reaches a second insulating film stacked on a side surface of the portion to be connected, the side surface being on a side of the opening portion.   
     
     
         9 . The semiconductor device according to  claim 1 , wherein
 the low-resistance film has a stacked structure in which a plurality of low-resistance films is formed by stacking, and   an end portion of the low-resistance film stacked closer to a center of the vertical hole is formed to extend longer and closer to the portion to be connected.   
     
     
         10 . The semiconductor device according to  claim 1 , wherein
 the vertical electrode has a diameter of 10 μm or more and an aspect ratio of 1 or more.   
     
     
         11 . The semiconductor device according to  claim 1 , wherein
 an aspect ratio of a portion having a side wall not provided with the low-resistance film in a hole bottom of the vertical hole is less than 1 (excluding 0).   
     
     
         12 . A method of manufacturing a semiconductor device, the method comprising:
 a first step of forming a preliminary vertical hole in a base, the preliminary vertical hole having an insulating film exposed to a hole wall and having a hole bottom having a depth not reaching a portion to be connected;   a second step of forming a low-resistance film having a lower resistance value than a resistance value of the insulating film inside the preliminary vertical hole from above the insulating film;   a third step of opening the hole bottom of the preliminary vertical hole with the low-resistance film and the insulating film up to the portion to be connected by etching to form a vertical hole; and   a fourth step of forming a barrier metal film in the vertical hole communicating with the portion to be connected, and forming or filling a conductive material from above the barrier metal film to form a vertical electrode.   
     
     
         13 . The method of manufacturing a semiconductor device according to  claim 12 , wherein
 a step of etching the hole bottom of the preliminary vertical hole with the low-resistance film and the insulating film to an extent not to reach the portion to be connected and further forming the low-resistance film inside the preliminary vertical hole from above an etched portion is repeated once or more between the second step and the third step.   
     
     
         14 . The method of manufacturing a semiconductor device according to  claim 12 , wherein
 removal of the low-resistance film and the insulating film is performed by plasma etching, and   any one or more of a fluorocarbon gas, a hydrofluorocarbon gas, or a rare gas is used in the plasma etching.   
     
     
         15 . A solid-state image sensor including a vertical electrode formed in a vertical hole extending from an opening portion in a back surface of a semiconductor substrate toward a portion to be connected in a wiring layer stacked on a surface of the semiconductor substrate along a thickness direction of the semiconductor substrate, wherein
 the vertical electrode has a structure in which a barrier metal film and a conductive material are stacked sequentially from a side close to an insulating film exposed to the vertical hole, and   a low-resistance film having a lower resistance value than a resistance value of the insulating film is provided to lie between the barrier metal film and the insulating film except a vicinity of the portion to be connected.