Method for fabricating capacitor in semiconductor device

Details Method for fabricating capacitor in semiconductor device Method for fabricating capacitor in semiconductor device

2000-04-26

2001-07-31

Dang, Trung (Department: 2823)

Semiconductor device manufacturing: process

Making passive device

C438S239000, C438S240000, C438S253000, C438S396000

Reexamination Certificate

active

06268258

ABSTRACT:

This application claims the benefit of Korean patent application No. 42405/1999, filed Oct. 1, 1999, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a method for fabricating a capacitor in a semiconductor device, in which oxidization of upper and lower electrodes and wiring films is prevented during annealing a capacitor dielectric film for improving device characteristics.
2. Background of the Related Art
Methods for increasing a capacitance by forming a three dimensional capacitor electrode of a dielectric film of, such as SiO
2
, NO(Si
3
N
4
), Ta
2
O
5
, etc., have come to a limit as a semiconductor device packing density increases in a geometrical series. Recently, a method using a material of a high dielectric constant, such as BST (Barium Strontium Titanium Oxide), and PZT (Lead Zirconium Titanium Oxide) as the dielectric film has been suggested. The dielectric film of a high dielectric constant can lower fabrication costs and improve device reliability. However, because a direct deposition of the dielectric film of a high dielectric constant on a silicon substrate forms a silicon oxide film at an interface, which reduces total charge sharply, films with an excellent acid resisting property, such as Pt or Ir are used as the upper and lower electrodes of the dielectric film of a high dielectric constant. However, such use of Pt and Ir acts as a factor increasing product cost, since the Pt and Ir are not only expensive, but also difficult to use in fabrication processes, such as etching and etc. Moreover, since the electrodes of noble metals act as catalytic that decomposes H
2
molecule, which flows in an ILD(Inter Layer Dielectric) process or an IMD(Inter Metal Dielectric) process, into H atoms, the electrodes of noble metals accelerate degradation of the dielectric film of a high dielectric constant. Those methods for fabricating a capacitor of a dielectric film of a high dielectric constant in a semiconductor device have the following problems.
The degradation of the dielectric film caused by catalytic effect of the upper and lower electrodes of the capacitor deteriorates device reliability. The degradation of the dielectric film occurs, not only in the ILD or IMD process, but also in H
2
forming process by a flowing H
2
gas conducted for decreasing resistivity and improving transistor characteristics after a wiring process.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method for fabricating a capacitor in a semiconductor device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a method for fabricating a capacitor in a semiconductor device, in which oxidization of the upper or lower electrodes or wiring is prevented in annealing a capacitor dielectric film for improving a device characteristics.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
An object of the present invention is to provide a method for fabricating a capacitor in a semiconductor device, the capacitor having a lower electrode, a dielectric film formed on a surface of the lower electrode, and an upper electrode formed on the dielectric film, the method comprising the steps of: forming the dielectric film of at least one oxide selected from a group of oxides of Lead (Pb), Zirconium (Zr), Tantalum (Ta), Barium (Ba), Strontium (Sr), and Titanium (Ti); forming the upper electrode and the lower electrode of the capacitor with a metal having a standard Gibbs free energy greater than a oxide metal of the dielectric film; and, annealing to crystallize the dielectric film in an atmosphere of which partial pressure ratio of P
H20
/P
H2
is 10E-20 ~10E0.
Another object of the present invention is to provide a method for fabricating a capacitor in a semiconductor device, comprising the steps of: forming an interlayer insulating layer having a storage node contact hole on a semiconductor substrate; forming a contact plug layer filling the storage node contact hole; forming a lower electrode made of Tungsten in contact with the contact plug layer, and depositing BSTO to form a dielectric layer; crystallizing the dielectric film at a temperature of 700 K~1200 K in an atmosphere of which partial pressure ratio of P
H20
/P
H2
is 10E-20~10E0; and forming an upper electrode made of Tungsten on the dielectric layer.
Another object of the present invention is to provide a method for fabricating a capacitor in a semiconductor device, comprising the steps of: forming an interlayer insulating layer having a storage node contact hole on a semiconductor substrate; forming a contact plug layer filling the storage node contact hole; forming a lower electrode made of Tungsten in contact with the contact plug layer; depositing BSTO to form a dielectric layer; forming an upper electrode made of Tungsten on the dielectric layer; forming an ILD layer on an entire surface of the semiconductor substrate including the upper electrode; selectively etching the ILD layer to form a metal wiring contact hole; forming a metal wiring plug layer to fill the metal wiring contact hole; forming a metal wiring; forming an IMD layer on an entire surface of the ILD layer including the metal wiring; and crystallizing the dielectric film while at the same time annealing the metal wiring at a temperature of 700 K~1200 K in an atmosphere of which partial pressure ratio of P
H20
/PH
2
is 10E-20~10E0.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 5554559 (1996-09-01), Wolters et al.
patent: 5909043 (1999-06-01), Summerfelt
patent: 6201271 (2001-03-01), Okutoh et al.
patent: 689236 A1 (1995-12-01), None
patent: 920061 A2 (1999-06-01), None
patent: 960869 A2 (1999-12-01), None
Byung Hak Lee et al., In-situ Barrier Formation for High Reliable W/barrier/poly-Si Gate Using Denudation of WNxon Polycrystalline Si, IEDM, 1998, pp. 385-388.

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