Semiconductor device manufacturing: process – Making passive device – Stacked capacitor
Reexamination Certificate
1999-01-05
2001-05-08
Whitehead, Jr., Carl (Department: 2812)
Semiconductor device manufacturing: process
Making passive device
Stacked capacitor
C438S253000, C438S255000, C438S398000, C438S791000
Reexamination Certificate
active
06228737
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of manufacturing a capacitor of a memory. Specifically, this invention relates to a method of forming a capacitor insulating film over a lower electrode of a capacitor.
2. Description of the Related Art
With high integration and densification of a VLSI, the dimensions of a device have been miniaturized in recent years. With their miniaturization, the capacity of a capacitor decreases as a result of a reduction in the area of the capacitor. In order to improve this, there is known a method of forming a low-layer silicon nitride film and a Ta
2
O
5
film on doped polysilicon for a capacitor lower electrode as a capacitor insulating film.
The method of forming the nitride film and the Ta
2
O
5
will be explained below.
An interlayer insulating film is formed over a doped silicon substrate. A lower electrode corresponding to polysilicon is formed on the interlayer insulating film. A RTN (Rapid Thermal Nitrization) process is effected on the surface of the doped polysilicon in an atmosphere of NH
3
at temperatures ranging from 700° C. to 1000° C. to thereby form a low-layer silicon nitride film. Subsequent to this formation, a Ta
2
O
5
film is deposited on the low-layer nitride film by an LPCVD (Low Pressure Chemical Vapor deposition) method. Annealing is effected on the Ta
2
O
5
film in an atmosphere of oxidation at a temperature of 600° C. or more. Thus, the Ta
2
O
5
film is formed as a capacitor insulating film. Doped polysilicon or TiN is deposited on the capacitor insulating film by the LPCVD method and thereafter subjected to patterning. A capacitor is completed in the above-described manner.
SUMMARY OF THE INVENTION
An object of this invention is to provide a method of manufacturing a capacitor, which is capable of preventing oxidation of a lower electrode even if a low-layer nitride film is thin.
According to one aspect of this invention, for achieving the above object, there is provided a method of manufacturing a semiconductor device, comprising a step for forming CVD silicon nitride film over a lower electrode formed on a semiconductor substrate by a CVD method, a step for subjecting the semiconductor substrate to heat treatment in a nitride atmosphere subsequent to the above step to thereby form thermal silicon nitride film on the lower electrode, a step for forming a capacitor insulating film over the thermal silicon nitride film and the CVD silicon nitride film, and a step for forming an upper electrode over the capacitor insulating film.
Further, the present application discloses other various inventions made to achieve the above object. They will become apparent from the following claims, respective embodiments and accompanying drawings.
REFERENCES:
patent: 5518946 (1996-05-01), Kuroda
patent: 5930106 (1999-07-01), Deboer et al.
Jones Volentine, LLC
Jr. Carl Whitehead
OKI Electric Industry Co., Ltd.
Thomas Toniae M.
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