SEMICONDUCTOR DEVICE MANUFACTURING METHOD AND SEMICONDUCTOR DEVICE
A stopper film, a sacrifice film, and a beam configuration material film are formed by laminating the films in this order on a semiconductor substrate. A cylinder hole that penetrates the stopper film, the sacrifice film, and the beam configuration material film is formed, and a lower electrode that covers the inner surface of the cylinder hole is formed. The beam configuration material film is patterned so as to form a beam that is connected to at least a part of the outer circumferential surface of the lower electrode, thereby exposing a part of the sacrifice film. The sacrifice film is removed by wet etching, and a hollow is formed in the surface of the beam, said hollow being deeper than a hollow formed in the surface of the stopper film.
1 . A semiconductor device manufacturing method comprising:
laminating a stopper film, a sacrificial film, and a beam constituent material film in succession on a semiconductor substrate;
forming a cylinder hole that penetrates the stopper film, the sacrificial film, and the beam constituent material film;
forming a lower electrode that covers an inner surface of the cylinder hole;
patterning the beam constituent material film so as to form a beam that is connected to at least a portion of the external circumferential surface of the lower electrode thereby, exposing a portion of the sacrificial film; and
removing the sacrificial film with wet etching and forming a hollow in the surface of the beam that is deeper than a hollow formed in the surface of the stopper film.
2 . The method of claim 1 , wherein the stopper film and the beam constituent material film are formed using the same starting materials, and the etching rate of an etching liquid used for the wet etching up to a prescribed depth from at least the upper and lower surfaces of the beam constituent material film, is faster than that of the stopper film.
3 . The method of claim 2 , wherein the etching rate for the upper and lower surfaces of the beam constituent material film is 1.2 to 3 times the etching rate for the stopper film.
4 . The method of claim 2 , wherein the stopper film and the beam constituent material film are both silicon nitride films.
5 . The method of claim 4 , wherein the stopper film and the beam constituent material film are formed with a plasma CVD method using trimethyldisilane, SiH 4 , and NH 3 as source gases.
6 . The method of claim 5 , wherein the flow rates of the SiH 4 and the NH 3 when forming the beam constituent material film are the same as the respective flow rates of the SiH 4 and the NH 3 when forming the stopper film, and the flow rate of the trimethyldisilane for forming a layer up to a prescribed depth from at least the surface of the beam constituent material film, is less than the flow rate of the trimethyldisilane for forming the stopper film.
7 . The method of claim 1 , wherein the beam constituent material film is a single-layer film.
8 . The method of claim 1 , wherein the beam constituent material film is a three-layer structure film.
9 . The method of claim 1 , wherein patterning of the beam constituent material film is performed before forming the cylinder hole, and the lower electrode is connected to the beam thereafter due to the formation of the cylinder hole in such a way that a portion of the inner surface thereof is formed by the beam constituent material film.
10 . The method of claim 1 , wherein patterning of the beam constituent material film is performed so that the lower electrode is coupled to another lower electrode by the beam.
11 . The method of claim 1 , wherein a capacitance insulating film is further formed over the entire surface including an exposed surface of the lower electrode that is exposed by the removal of the sacrificial film, and an upper electrode is formed on the capacitance insulating film.
12 . The method of claim 4 , wherein the sacrificial film is a silicon oxide film.
13 . The method of claim 1 , wherein the sacrificial film is formed by laminating a plurality of films using different film formation methods.
14 . A semiconductor device comprising:
a lower electrode having a lower end part, an upper end part, and an external circumferential surface continuous from the lower end part to the upper end part;
a stopper film connected to the external circumferential surface of the lower end part and formed with a hollow on the upper surface thereof; and
a beam connected to at least a portion of the external circumferential surface at a position remote from the lower end part, and having hollows connected on the upper surface and lower surface thereof;
wherein the depth of the hollows formed in the upper surface and lower surface of the beam is greater than the depth of the hollow formed in the upper surface of the stopper film.
15 . The semiconductor device of claim 14 , wherein the stopper film and the beam comprise the same material, and at least a portion of the upper surface and the lower surface of the beam has a different composition ratio than the stopper film.
16 . The semiconductor device of claim 14 , comprising:
a capacitance insulating film formed continuously from the external circumferential surface to the upper surface of the stopper film and to the upper surface and the lower surface of the beam; and
an upper electrode formed on the capacitance insulating film.
17 . The semiconductor device of claim 14 , wherein the beam couples the lower electrode with another lower electrode.