Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
2002-04-16
2004-05-11
Zarabian, Amir (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
C257S296000, C257S300000, C257S310000
Reexamination Certificate
active
06734489
ABSTRACT:
TITLE OF THE INVENTION
Semiconductor Device comprising MIM-type Capacitor and Method of Manufacturing The Same
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to a semiconductor device which comprises an MIM (Metal Insulator Metal)-type capacitor using copper and a method of manufacturing the same.
2. Description of the Background Art
FIG. 94
is a cross section showing a structure of a semiconductor device comprising a capacitor in the background art. In an upper surface of a silicon substrate
101
formed is an isolation insulating film
102
made of a silicon oxide film. In an element formation region defined by the isolation insulating film
102
, a MOS transistor is formed. The MOS transistor has a gate structure consisting of a gate oxide film
103
, a gate electrode
104
and sidewalls
105
and source/drain regions
106
which are paired with each other with a channel region below the gate structure interposed therebetween. On the isolation insulating film
102
formed is a PIP (Polysilicon Insulator polysilicon)-type capacitor having a lower electrode
116
and an upper electrode
118
both of which are made of polysilicon and a dielectric film
117
of ON (Oxide Nitride) structure. The PIP-type capacitor can be formed with no additional complicate process since its upper electrode and lower electrode are each made of a polysilicon film which is widely used in a manufacturing process for a semiconductor device.
On the silicon substrate
101
formed is an interlayer insulating film
107
covering the MOS transistor and the PIP-type capacitor. In the interlayer insulating film
107
formed are a plurality of plugs
108
connected to the source/drain regions
106
of the MOS transistor and the upper electrode
118
and the lower electrode
116
of the PIP-type capacitor. On the interlayer insulating film
107
, a first interconnection layer is formed. The first interconnection layer has an insulating film
109
, a plurality of metal wires
110
formed in the insulating film
109
and a plurality of plugs
111
connected to the metal wires
110
. The metal wires
110
are connected to the plugs
108
, respectively.
On the first interconnection layer, a second interconnection layer is formed. The second interconnection layer has an insulating film
112
, a plurality of metal wires
113
formed in the insulating film
112
and a plurality of plugs
114
connected to the metal wires
113
. The metal wires
113
are connected to the plugs
111
, respectively. On the second interconnection layer formed are a plurality of metal wires
115
connected to the plugs
114
, respectively.
The PIP-type capacitor, however, whose voltage coefficient (VCC) is about 220 ppm/V and temperature coefficient (TCC) is about 120 ppm/° C., which cause a relatively large variation in capacitance due to voltage variation and temperature variation, has a problem of unstable characteristics against voltage variation and temperature variation. Further, since the resistance value of polysilicon is relatively large, especially when the PIP-type capacitor is used for a radio frequency circuit, there arises a problem of low stability of circuit operation.
In an attempt to solve the problems of the PIP-type capacitor, recently, there has been a promotion of development of an MIM-type capacitor having an upper electrode and a lower electrode made of a metal. The MIM-type capacitor, whose VCC value is a fifth to a sixth of that of the PIP-type capacitor and TCC value is a half of that of the PIP-type capacitor or lower, has high stability of characteristics against voltage variation and temperature variation. Further, since a metal has lower resistance value than polysilicon, when the MIM-type capacitor is used for a radio frequency circuit, the stability of circuit operation is improved as compared with the case of using the PIP-type capacitor.
The MIM-type capacitor is formed together with the metal wires in a BEOL (Back End Of the Line) process which is one of the semiconductor manufacturing processes. In the background-art BEOL process, an aluminum wire is generally used as a metal wire. Since there has arisen a problem of wire delay in aluminum wire as devices have become smaller, however, a copper wire which has lower resistance than the aluminum wire has been recently being used. The copper wire is generally formed in a damascene process, not in an etching process, due to the difficulty of copper in patterning by etching unlike aluminum. Therefore, forming an MIM-type capacitor having copper electrodes needs a new structure and a new process, unlike the MIM-type capacitor having aluminum electrodes in the background art.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor device and a method of manufacturing the same, in which an MIM-type capacitor can be formed together with metal wires with no additional complicate process when the metal wires are formed by a damascene process step in the BEOL process.
According to a first aspect of the present invention, the semiconductor device includes a substrate, a semiconductor element, an interlayer insulating film, and an MIM (Metal Insulator Metal)-type capacitor. The semiconductor element is formed on the substrate. The interlayer insulating film is so formed on the substrate as to cover the semiconductor element. The capacitor is formed in the interlayer insulating film and electrically connected to the semiconductor element. The capacitor has a first metal film, a dielectric film, and a second metal film. The first metal film is formed on side surfaces and a bottom surface of a recess defined in the interlayer insulating film, serving as a first electrode. The dielectric film is formed on the first metal film. The second metal film fills the recess and is opposed to the first metal film with the dielectric film interposed therebetween, serving as a second electrode.
In this semiconductor device, the first electrode is formed not only on the bottom surface of the recess but also on the side surfaces thereof. Therefore, the area in which the first electrode and second electrode are opposed to each other is enlarged and the capacitor capacitance is thereby increased.
According to a second aspect of the present invention, the semiconductor device includes a substrate, a semiconductor element, an interlayer insulating film, and an MIM (Metal Insulator Metal)-type capacitor. The semiconductor element is formed on the substrate. The interlayer insulating film is so formed on the substrate as to cover the semiconductor element. The capacitor is formed in the interlayer insulating film and electrically connected to the semiconductor element. The interlayer insulating film has a predetermined insulating layer. The capacitor has a first metal film, a dielectric film, and a second metal film. The first metal film is formed in a main surface of the insulating layer, serving a first electrode. The dielectric film is formed on a side surface of the first metal film in the main surface of the insulating layer. The second metal film is opposed to the first metal film with the dielectric film interposed therebetween in the main surface of the insulating layer, serving as a second electrode.
In this semiconductor device, since the first electrode and the second electrode are formed in the same plane, the flatness of surface is improved as compared with the case where the first electrode and the second electrode are layered. Therefore, when the MIM-type capacitor is formed in the multi-level wire structure, it is possible to suppress level difference in the surfaces of interconnection layers.
According to a third aspect of the present invention, the semiconductor device includes a substrate, a semiconductor element, an interlayer insulating film, and an MIM (Metal Insulator Metal)-type capacitor. The semiconductor element is formed on the substrate. The interlayer insulating film is so formed on the substrate as t
Goto Kinya
Matsumoto Masahiro
Morimoto Noboru
Renesas Technology Corp.
Soward Ida M.
Zarabian Amir
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