SEMICONDUCTOR DEVICE
To provide a semiconductor device including a capacitor which includes a cylindrical or columnar lower electrode, a support film in contact with the upper portion of the lower electrode for supporting the lower electrode, a dielectric film covering the lower electrode and the support film, and an upper electrode facing the lower electrode with the dielectric film interposed therebetween, wherein the dielectric film has a first thickness on the upper surface of the support film and a second thickness thinner than the first thickness on the side surface of the lower electrode, and thereby the mechanical strength of the support film is increased.
1 . A semiconductor device provided with a capacitor comprising:
a cylindrical or columnar lower electrode;
a support film in contact with the upper portion of the lower electrode;
a dielectric film covering the lower electrode and the support film; and
an upper electrode facing the lower electrode with the dielectric film interposed therebetween,
wherein the dielectric film has a first thickness on the upper surface of the support film and a second thickness thinner than the first thickness on the side surface of the lower electrode.
2 . The semiconductor device according to claim 1 , wherein the second thickness is a thickness of the dielectric film at a position lower than the position at which the lower electrode is in contact with the support film.
3 . The semiconductor device according to claim 2 , wherein in the dielectric film, a ratio of dA/dB, in which dA is the first thickness and dB is the second thickness, is 1.25 or more.
4 . The semiconductor device according to claim 1 , wherein the support film is in contact with the upper side edge of the lower electrode.
5 . The semiconductor device according to claim 4 , wherein the first thickness is a maximum thickness of the dielectric film.
6 . The semiconductor device according to claim 1 , wherein the second thickness of the dielectric film is a thickness that satisfies a predetermined capacitance value of the capacitor.
7 . The semiconductor device according to claim 1 , wherein the support film has a film thickness of 60 nm or less.
8 . The semiconductor device according to claim 7 , wherein the support film comprises silicon nitride.
9 . The semiconductor device according to claim 1 , wherein the dielectric film comprises zirconium oxide.
10 . The semiconductor device according to claim 9 , wherein the dielectric film is a film formed by interposing an aluminum oxide layer between layers including the zirconium oxide.
11 . The semiconductor device according to claim 10 , wherein the difference between the first thickness and the second thickness is a difference of the total thicknesses of the layers including the zirconium oxide at the respective positions.
12 . The semiconductor device according to claim 1 , wherein the lower electrode is connected to a contact pad and further the contact pad is connected to an impurity diffusion layer via a contact plug.
13 . The semiconductor device according to claim 12 , wherein the device comprises a memory cell region comprising a plurality of the capacitors and a peripheral circuit region provided around the memory cell region, and the support film is provided within the memory cell region.
14 . A semiconductor device comprising:
a first conductor film perpendicularly standing on a substrate;
a support film in contact with the upper portion of the first conductive film; and
a dielectric film covering the first conductor film and the support film,
wherein the dielectric film has a first thickness on the upper surface of the support film and a second thickness thinner than the first thickness on the side surface of the first conductor film at a position lower than the position at which the first conductor film is in contact with the support film.
15 . The semiconductor device according to claim 14 , wherein the first thickness is a thickness sufficient to suppress an occurrence of cracks in the support film.
16 . The semiconductor device according to claim 14 , wherein the first conductor film is a lower electrode of a capacitor, and the second thickness is a thickness that satisfies a predetermined capacitance value of the capacitor.
17 . The semiconductor device according to claim 16 , wherein the lower electrode is formed in a cylindrical or columnar shape having a sufficient surface area that satisfies a predetermined capacitance value of the capacitor.
18 . The semiconductor device according to claim 17 , further comprising an upper electrode facing the lower electrode with the dielectric film interposed therebetween.
19 . The semiconductor device according to claim 18 , wherein the lower electrode has a cylindrical shape and the upper electrode is faced an inner wall of the lower electrode with the dielectric film interposed therebetween.
20 . The semiconductor device according to claim 18 , wherein the upper electrode comprises a second conductor film formed on the dielectric film and a filling film formed on the second conductor film to fill gaps under the support film.