Semiconductor device manufacturing: process – Making passive device – Stacked capacitor
Reexamination Certificate
2002-09-26
2004-03-09
Lebentritt, Michael S. (Department: 2824)
Semiconductor device manufacturing: process
Making passive device
Stacked capacitor
C438S398000, C438S410000, C438S412000, C438S459000
Reexamination Certificate
active
06703285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing an MIM (metal film—insulating film—metal film) capacitor structure and to a method for manufacturing an MIM capacitor element, and more particularly to a method for forming an MIM capacitor structure on a semiconductor wafer provided with an integrated circuit.
2. Description of the Related Art
The following techniques are used to form MIM capacitor structures on semiconductor wafers provided with integrated circuits.
Specifically, there are methods in which a bottom electrode film (for example, an AlCu film) is formed by sputtering on a semiconductor wafer, an insulating film (for example, an SiON film) is formed by CVD thereon, and a top electrode film (for example, a TiN film) is formed by sputtering on the insulating film.
Sputtering is a method in which inert gas ions (for example, those of Ar gas) produced by a plasma discharge are accelerated by an electric field and directed to a target (starting material to be vapor-deposited), the atoms in the target surface are flicked out, and the flicked-out atoms are deposited on a semiconductor wafer, yielding a thin film.
In sputtering, however, the species flicked out during the formation of the top electrode film are not limited solely to the atoms that constitute the target, but also include the high-energy electrons present in the plasma region in the vicinity of the target. When these electrons collide with the top electrode film during the formation process, electric charges accumulate on the top electrode film, which is one of the electrodes of an MIM capacitor structure. An electric discharge occurs when the electric charges accumulate beyond the withstand voltage limit of the insulating film on the top electrode film during the formation process. At this point, the insulating film is broken down electrostatically (this type of breakdown will be referred to hereinbelow as an “electrostatic breakdown”).
A resulting drawback is that an electrostatically broken-down MIM capacitor structure or a capacitor structure fabricated using this MIM capacitor structure becomes incapable of operating in regular manner.
SUMMARY OF THE INVENTION
The present invention was created in order to overcome the above-described drawback of the prior art. An object of the present invention is to provide a method for manufacturing a capacitor structure and a method for manufacturing a capacitor element that allow percent defective to be reduced by controlling the accumulation of electric charges on the top electrode film as a factor that brings about electrostatic breakdown of an insulating film.
A method for manufacturing a capacitor structure in accordance with the present invention comprises the steps of forming a bottom electrode film
21
on a substrate
10
, forming an insulating film
22
in the area of the bottom electrode film
21
that excludes a specific area
21
a
, bringing a grounded conductive member
31
into contact with the specific area
21
a
of the bottom electrode film
21
, forming a top electrode film
23
on the insulating film
22
by performing sputtering such that part thereof is in contact with the specific area
21
a
of the bottom electrode film
21
, and separating the conductive member
31
from the specific area
21
a
of the bottom electrode film
21
.
Another method for manufacturing a capacitor structure in accordance with the present invention comprises the steps of forming a bottom electrode film
51
on a substrate
10
, disposing a first clamp ring
61
whose inside diameter is less than the outside diameter of the bottom electrode film
51
above the bottom electrode film
51
in the vicinity of the external periphery thereof, forming an insulating film
52
in an area not covered by the first clamp ring
61
on the bottom electrode film
51
, separating the first clamp ring
61
from the upper portion of the bottom electrode film
51
, bringing a grounded second clamp ring
62
whose inside diameter is less than the outside diameter of the bottom electrode film
51
but greater than the inside diameter of the first clamp ring
61
into contact with the bottom electrode film
51
in the vicinity of the external periphery thereof, forming a top electrode film
53
on the insulating film
52
by performing sputtering such that part thereof is in contact with the bottom electrode film
51
, and separating the second clamp ring
62
from the upper portion of the bottom electrode film
51
.
Yet another method for manufacturing a capacitor structure comprises the steps of forming a bottom electrode film
71
on a substrate
10
, forming an insulating film
72
on the bottom electrode film
71
, bringing a grounded clamp ring
81
whose inner wall is formed substantially perpendicularly to the surface or the substrate
10
or whose inner wall is formed at an incline toward the center of the substrate
10
into contact with the area in the vicinity of the external periphery of an insulating film
72
, forming a top electrode film
73
by sputtering on the insulating film
72
and in the upper portion of the clamp ring
81
with the inner wall, and separating the clamp ring
81
from the insulating film
72
.
Still another method for manufacturing a capacitor structure in accordance with the present invention comprises the steps of forming a bottom electrode film
91
on the substrate
10
, forming an insulating film
92
on the bottom electrode film
91
, and forming a top electrode film
93
on the insulating film
92
by performing sputtering in a state in which a member kept at a negative potential is disposed around the substrate
10
.
An additional method for manufacturing a capacitor element in accordance with the present invention comprises the steps of forming a capacitor structure on a substrate by any of the manufacturing methods described above, and partially removing the bottom electrode film
21
, insulating film
22
, and top electrode film
23
constituting the capacitor structure to form a single capacitor element or a plurality of capacitor elements from the remaining bottom electrode film
21
, insulating film
22
, and top electrode film
23
.
REFERENCES:
patent: 5049514 (1991-09-01), Mori
patent: 5805408 (1998-09-01), Maraschin et al.
patent: 5847918 (1998-12-01), Shufflebotham et al.
patent: 6096404 (2000-08-01), Ghantiwala
patent: 6291315 (2001-09-01), Nakayama et al.
patent: 6492911 (2002-12-01), Netzer
patent: 7-24261 (1995-03-01), None
patent: 63237567 (1998-10-01), None
patent: 2001250795 (2001-09-01), None
Arakawa Yoshikazu
Hashimoto Keiichi
Oki Electric Industry Co. Ltd.
Volentine & Francos, PLLC
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