MANUFACTURING METHOD OF SEMICONDUCTOR DEVICE
A capacitor in which a ferroelectric film ( 4 ) is held between a lower electrode ( 3 ) and an upper electrode ( 5 ) is formed above a conductive plug ( 1 ), with a conductive base structure ( 2 ) interposed therebetween. A hard mask ( 6 ) used in patterning the conductive base structure ( 2 ) is formed over the upper electrode ( 5 ). A protective film ( 7 ) covering at least an exposed portion of the ferroelectric film ( 4 ) is formed and then heat treatment is applied to the ferroelectric film ( 4 ) in an oxygen gas atmosphere. This prevents elements constituting the ferroelectric film ( 4 ) from being released to the outside at the time of the heat treatment by thus forming the protective film ( 7 ) before applying the heat treatment to the ferroelectric film ( 4 ). Further, oxygen penetration into the conductive plug ( 1 ) is blocked by applying the heat treatment in the state where the conductive base structure ( 2 ) is not patterned.
1 . A manufacturing method of a semiconductor device, comprising:
forming a conductive plug above a semiconductor substrate;
forming a conductive base structure over the conductive plug;
forming a capacitor with a capacitor film held between a lower electrode and an upper electrode, over the conductive base structure;
forming a mask used when patterning the conductive base structure, above the upper electrode;
forming a protective film covering at least an exposed portion of the capacitor film after forming the mask; and
applying heat treatment to the capacitor film in an oxidizing gas atmosphere in a state where the protective film is formed.
2 . The manufacturing method of a semiconductor device according to claim 1 ,
wherein the protective film is a film containing at least any one kind of an aluminum oxide, a titanium oxide and lead zirconate titanate.
3 . The manufacturing method of a semiconductor device according to claim 1 ,
wherein the conductive base structure includes an oxidation preventing film preventing oxidation of the conductive plug.
4 . The manufacturing method of a semiconductor device according to claim 1 ,
wherein said step of forming the conductive base structure comprises the steps of:
forming a conductive film over the conductive plug and an interlayer insulating film with the conductive plug formed therein, and
flattening a top surface of the conductive film.
5 . The manufacturing method of a semiconductor device according to claim 4 , further comprising the step of applying plasma processing to the top surface of the conductive film in an atmosphere of gas containing nitrogen, after flattening the top surface of the conductive film.
6 . The manufacturing method of a semiconductor device according to claim 5 , wherein the gas containing nitrogen is NH 3 (ammonia) gas.
7 . The manufacturing method of a semiconductor device according to claim 4 , wherein in said step of flattening the top surface of the conductive film, the conductive film is flattened until a surface of the interlayer insulating film is exposed.
8 . The manufacturing method of a semiconductor device according to claim 1 , further comprising the steps of:
leaving the protective film over only a side wall of the capacitor by etching an entire surface of the protective film, after performing the heat treatment; and
patterning the conductive base structure by using the mask after performing etching for the protective film.
9 . The manufacturing method of a semiconductor device according to claim 8 , further comprising the step of forming a hydrogen diffusion preventing film preventing diffusion of hydrogen to the capacitor film, after patterning the conductive base structure.
10 . The manufacturing method of a semiconductor device according to claim 1 , wherein said step of performing heat treatment is carried out under a condition of a temperature of the semiconductor substrate of 550° C. to 700° C.
11 . The manufacturing method of a semiconductor device according to claim 1 , wherein the oxidizing gas is gas including at least any one of oxygen (O 2 ) gas, nitrogen monoxide (N 2 O) gas and ozone (O 3 ) gas.
12 . The manufacturing method of a semiconductor device according to claim 1 , wherein in said step of forming the capacitor, at least the upper electrode and the capacitor film are collectively patterned.
13 . The manufacturing method of a semiconductor device according to claim 1 , wherein the capacitor film is a film constituted of a ferroelectric material.
14 . The manufacturing method of a semiconductor device according to claim 1 , wherein the upper electrode is a film including at least any one kind of metal out of 1 r (iridium), Ru (ruthenium), Pt (platinum), Rh (rhodium), Re (rhenium), Os (osmium) and Pd (palladium), or a film including an oxide in the one kind of metal.
15 . The manufacturing method of a semiconductor device according to claim 1 , wherein the lower electrode is a film including at least any one kind of metal out of Ir (iridium), Ru (ruthenium), Pt (platinum) and Pd (palladium), or a film including an oxide in the one kind of metal.
16 . The manufacturing method of a semiconductor device according to claim 1 , wherein the protective film is formed by a sputtering method, an MOCVD method or an ALD method.
17 . The manufacturing method of a semiconductor device according to claim 1 , wherein a film thickness of the protective film is 1 nm to 50 nm.
18 . The manufacturing method of a semiconductor device according to claim 1 , wherein the capacitor film forms a compound film of a perovskite structure or a compound film of a Bi-layer structure.
19 . The manufacturing method of a semiconductor device according to claim 3 , wherein the oxidation preventing film is formed by a conductor selected from a group constituted of TiAlN (titanium-aluminum nitride), TiAlON (titanium-aluminum oxynitride), Ir (iridium) and Ru (ruthenium).