Semiconductor memory device and method of fabricating the same
A semiconductor memory includes a memory cell array area provided with first and second memory cells and having a first active area and a first element isolation area constituting a line & space structure, and having a floating gate electrode and a control gate electrode in the first active area, a word line contact area adjacent to the memory cell array area and having a second active area, first and second word lines with a metal silicide structure, functioning respectively as the control gate electrodes of the first and second memory cells and arranged to straddle the memory cell array area and the word line contact area. A dummy gate electrode is arranged just below the first and second word lines in the second active area.
1. A semiconductor memory device, comprising:
a semiconductor substrate including a first region and a second region located adjacent to the first region,
the first region including a first active area sectionalized by a first element isolation area extending to a first direction,
the second region including second active areas sectionalized by second element isolation areas extending to the first direction;
first and second word lines extending from the first region to the second region and connecting to memory cells, said first and second word lines located parallel to each other and extending to a second direction perpendicular to the first direction
a first insulating film provided between the first and second word lines and directly contacting to one side of the first word line and contacting to one side of the second word line, and the first insulating film including a void; and
first and second contacts provided respectively corresponding to the first and second word lines in the second region,
wherein a first bottom portion of the void on one of the second active areas is higher than a second bottom portion of the void on the second element isolation area.
2. The semiconductor memory device according to claim 1 ,
wherein the first and second word lines include a polysilicon film and a metal silicide film formed on the polysilicon film.
3. The semiconductor memory device according to claim 2 ,
wherein the metal silicide film is constituted from one material selected from the group consisting of WSi, CoSi, NiSi and TiSi.
4. The semiconductor memory device according to claim 1 ,
wherein each of the memory cells includes a charge accumulation layer and an inter-gate insulating film provided on the charge accumulation layer, and a top of the void is higher than an inter-gate insulating film on the first active area.
5. The semiconductor memory device according to claim 4 ,
wherein in the first active area, a top of the void is closed by the first insulating film.
6. The semiconductor memory device according to claim 1 ,
wherein in one of the second active areas, the void includes an opening at an upper portion, and the opening of the void is closed by a second insulating film.
7. The semiconductor memory device according to claim 1 ,
wherein in the first active area, a top of the void is closed by the first insulating film.
8. The semiconductor memory device according to claim 1 , wherein a width of one of the second active areas is wider than a width of the first active area.