Semiconductor device with transistor and capacitor and its manufacture method
View Patent ↗On a semiconductor substrate, a transistor and a capacitor electrically connected to the transistor are formed, the capacitor having two electrodes made of metal and a capacitor dielectric layer between the two electrodes made of oxide dielectric material. A temporary protective film is formed over the capacitor, the temporary protective film covering the capacitor. The semiconductor substrate with the temporary protective film is subjected to a heat treatment in a reducing atmosphere. The temporary protective film is removed. The semiconductor substrate with the temporary protective film removed is subjected to a heat treatment in an inert gas atmosphere or in a vacuum state. A protective film is formed over the capacitor, the protective film covering the capacitor. With these processes, leak current of the capacitor can be reduced.
1. A method of manufacturing a semiconductor device, comprising the steps of:
(a) forming a transistor and a capacitor electrically connected to the transistor on a semiconductor substrate, the capacitor having two electrodes consisting of metal and a capacitor dielectric layer between the two electrodes consisting of oxide dielectric material;
(b) forming a temporary protective film on or over the capacitor, the temporary protective film covering the capacitor;
(c) subjecting the semiconductor substrate with the temporary protective film to a heat treatment in a reducing atmosphere;
(d) removing the temporary protective film;
(e) subjecting the semiconductor substrate without the temporary protective film to a heat treatment in an inert gas atmosphere or in a vacuum state; and
(f) forming a protective film on or over the capacitor, the protective film covering the capacitor.
2. A method according to claim 1 , wherein the dielectric layer of the capacitor consists of tantalum oxide.
3. A method according to claim 1 , wherein the temporary protective film and the protective film consist of silicon nitride.
4. A method according to claim 1 , further comprising after said step (e) and before said step (f) a step of forming a hydrogen barrier layer on or over the capacitor, the hydrogen barrier layer covering the capacitor and consisting of insulating material harder to transmit hydrogen than the protective film.
5. A method according to claim 4 , wherein the hydrogen barrier layer consists of alumina or tantalum oxide.
6. A method of manufacturing a semiconductor device, comprising the steps of:
forming a transistor and a capacitor electrically connected to the transistor on a semiconductor substrate, the capacitor having two electrodes consisting of metal and a capacitor dielectric layer between the two electrodes consisting of oxide dielectric material;
forming a protective film on or over the capacitor, the protective film covering the capacitor;
subjecting the semiconductor substrate with the protective film to a heat treatment in a reducing atmosphere;
heating the protective film with a flash lamp to eliminate hydrogen contained in the protective film; and
subjecting the semiconductor substrate with the protective film after hydrogen elimination to a heat treatment in an inert gas atmosphere or in a vacuum state.
7. A method according to claim 6 , wherein the dielectric layer of the capacitor consists of tantalum oxide.
8. A method according to claim 6 , wherein the protective film consists of silicon nitride.
9. A method of manufacturing a semiconductor device, comprising the steps of:
forming a transistor and a capacitor electrically connected to the transistor on a semiconductor substrate, the capacitor having two electrodes consisting of metal and a capacitor dielectric layer between the two electrodes consisting of oxide dielectric material;
forming a protective film on or over the capacitor, the protective film covering the capacitor;
subjecting the semiconductor substrate with the protective film to a heat treatment in a reducing atmosphere;
forming a gettering film on the protective film, the gettering film consisting of material having hydrogen gettering ability;
subjecting the semiconductor substrate with the gettering film to a heat treatment; and removing the gettering film.
10. A method according to claim 9 , wherein the gettering film consists of titanium.
11. A method according to claim 9 , wherein the dielectric layer of the capacitor consists of tantalum oxide.
12. A method according to claim 9 , wherein the protective film consists of silicon nitride.
13. A method of manufacturing a semiconductor device, comprising the steps of:
forming a transistor and a capacitor electrically connected to the transistor on a semiconductor substrate, the capacitor having two electrodes consisting of metal and a capacitor dielectric layer between the two electrodes consisting of oxide dielectric material;
subjecting the semiconductor substrate with the transistor and capacitor to a heat treatment in a reducing atmosphere;
subjecting the semiconductor substrate to a heat treatment in an inert gas atmosphere or in a vacuum state after the heat treatment in the reducing atmosphere; and
forming a protective film on or over the capacitor, the protective film covering the capacitor.
14. A method according to claim 13 , wherein the dielectric layer of the capacitor consists of tantalum oxide.
15. A method according to claim 13 , wherein the protective film consists of silicon nitride.