Manufacturing method of semiconductor device
The present invention provides an MIM capacitor using a high-k dielectric film preventing degradation of breakdown field strength of the MIM capacitor and suppressing the increase of the leakage current. The MIM capacitor comprises a first metal interconnect, a fabricated capacitance film, a fabricated upper electrode, and a third metal interconnect. The MIM capacitor is realized by forming an interlayer dielectric film comprising silicon oxide so as to cover the first metal interconnect, then forming a first opening in the interlayer dielectric film to a region corresponding to a via hole layer in the interlayer dielectric film just above the first metal interconnect so as not to expose the upper surface of the first metal interconnect, then forming a second opening to the inside of the first opening so as to expose the surface of the first metal interconnect and then forming a capacitance film and a third metal interconnect.
1. A method of manufacturing a semiconductor device, the method comprising:
forming a first metal interconnect layer on a semiconductor substrate;
forming an interlayer dielectric film on the first metal interconnected layer;
forming an opening in a desired region of the interlayer dielectric film;
forming a capacitance dielectric film in the opening so as to be in contact with the first metal interconnect layer; and
forming a second metal interconnect layer in the opening and on the interlayer dielectric film, wherein
the opening is formed in a region intended to form capacitance of the interlayer dielectric film placed on the first metal interconnect layer by performing a lithography process at least twice; and
one of the two lithography processes is performed on the interlayer dielectric film remaining on the first metal interconnect layer with a thickness less than that of the interlayer dielectric film that is disposed between an upper surface of the first metal interconnect layer and a bottom of the second metal interconnect layer formed on the interlayer dielectric film at a periphery of the opening.
2. The method of manufacturing a semiconductor device according to claim 1 , wherein
the opening includes at least two types of a first opening and a second opening which have different planar shapes from each other;
the second opening is formed above the first metal interconnect layer; and
the first opening is formed above the second opening so that the upper end of the second opening and the bottom of the first opening are in contact with each other and that the second opening is formed inside the first opening.
3. The method of manufacturing a semiconductor device according to claim 2 , wherein
a distance between the first metal interconnect layer and the first opening is shorter than a distance between the upper surface of the first metal interconnect layer and the bottom of the second metal interconnect layer formed on the interlayer dielectric film.
4. A method of manufacturing a semiconductor device, the method comprising:
forming a first metal interconnect layer on a semiconductor substrate;
forming an interlayer dielectric film on the first metal interconnected layer;
forming an opening in the interlayer dielectric film; and
forming a capacitance dielectric film in the opening so as to be in contact with the first metal interconnect layer and forming a second metal interconnect layer, wherein
forming the opening includes forming a first opening by perforating a desired region in the interlayer dielectric film placed on the first metal interconnect layer from a surface of the interlayer dielectric film at a first thickness so as not to expose the first metal interconnect layer, and forming a second opening by perforating an inside of the first opening at a second thickness so as to reach the first metal interconnect layer; and
the second thickness is less than the first thickness.
5. The method of manufacturing a semiconductor device according to claim 4 , wherein
at least two kinds of openings different in planar shape from each other are overlapped in a vertical direction of the openings;
the second opening is formed on the first metal interconnect layer; and
the first opening is formed so as to be placed above the second opening and so that the second opening is formed inside the first opening.
6. The method of manufacturing a semiconductor device according to claim 4 , wherein
the second thickness is less than the thickness of the interlayer dielectric film which is between the upper surface of the first metal interconnect layer and the bottom of the second metal interconnect layer formed on the interlayer dielectric film at the periphery of the opening.
7. The method of manufacturing a semiconductor device according to claim 4 , wherein
the second thickness is 50 nm or more and 300 nm or less.
8. The method of manufacturing a semiconductor device according to claim 1 , wherein
the capacitance dielectric film comprises, as a main component, a dielectric film selected from silicon oxide, silicon nitride, tantalum oxide, hafnium oxide, zirconium oxide, lanthanum oxide, titanium oxide, aluminum oxide, PZT, STO, and BST.
9. The method of manufacturing a semiconductor device according to claim 1 , wherein
the first metal interconnect layer and the second metal interconnect layer comprise, as a main component, a metal selected from tungsten, titanium, tantalum, tungsten, molybdenum, and a nitride thereof, or copper or aluminum and alloys thereof.