Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
2002-03-19
2003-08-05
Nguyen, Cuong Quang (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
C257S306000
Reexamination Certificate
active
06603165
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device and a method for fabricating the semiconductor device, more specifically to a semiconductor device having an MIM (Metal-Insulation-Metal) capacitor and a method for fabricating the semiconductor device.
Capacitor elements are important members of LSI, etc. having analog circuits.
Conventionally the capacitor elements have used polysilicon layer, impurity diffused layers, etc. as the electrodes, but recently capacitor elements called MIM capacitors are noted.
An MIM capacitor is a capacitor comprising a capacitor insulation film between a pair of electrodes of a metal. MIM capacitors can improve capacitor precision and frequency characteristics, and are much noted.
However, the above-described MIM capacitors are all vulnerable to external noises. Techniques for making the MIM capacitors invulnerable to external noises have been required.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor device which can prevent noises from combining with the MIM capacitor, and a method for fabricating the semiconductor device.
According to one aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor substrate; a capacitor element formed above the semiconductor substrate and including a lower electrode, a capacitor insulation film formed on the lower electrode and an upper electrode formed on the capacitor insulation film; a shield layer formed at least either of above and below the capacitor element; and a lead-out interconnection layer formed between the capacitor element and the shield layer and electrically connected to the lower electrode or the upper electrode, a plurality of holes being formed in each of the shield layer and the lead-out interconnection layer.
According to another aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor substrate; a capacitor element formed above the semiconductor substrate and including a lower electrode, a capacitor insulation film formed on the lower electrode and an upper electrode formed on the capacitor insulation film; a lower shield layer formed below the capacitor element; an upper shield layer formed above the capacitor element; a lower electrode lead-out interconnection layer formed between the capacitor element and the lower shield layer and electrically connected to the lower electrode; and an upper electrode lead-out interconnection layer formed between the capacitor element and the upper shield layer and electrically connected to the upper electrode, a plurality of holes being formed in each of the lower shield layer, the upper shield layer, the lower electrode lead-out interconnection layer and the upper electrode lead-out interconnection layer, an area of parts of the lower shield layer and the lower electrode lead-out interconnection layer, which are opposed to each other, and an area of parts of the upper shield layer and the upper electrode lead-out interconnection layer, which are opposed to each other being respectively set so that a parasitic capacity between the lower shield layer and the lower electrode lead-out interconnection layer and a parasitic capacity between the upper shield layer and the upper electrode lead-out interconnection layer being substantially equal to each other.
According to farther another aspect of the present invention, there is provided a method for fabricating a semiconductor device comprising the step of forming above a semiconductor substrate a capacitor element including a lower electrode, a capacitor insulation film formed on the lower electrode and an upper electrode formed on the capacitor insulation film, the method comprising the steps of: forming a lower shield layer with a plurality of holes formed in, and forming a lower electrode lead-out interconnection layer with a plurality of holes formed in, before the step of forming the capacitor element.
According to farther another aspect of the present invention, there is provided a method for fabricating a semiconductor device comprising the step of forming above a semiconductor substrate a capacitor element including a lower electrode, a capacitor insulation film formed on the lower electrode and an upper electrode formed on the capacitor insulation film, the method comprising the steps of: forming an upper electrode lead-out interconnection layer with a plurality of holes formed in and forming an upper shield layer with a plurality of holes formed in, after the step of forming the capacitor element.
According to farther another aspect of the present invention, there is provided a method for fabricating a semiconductor device comprising the step of forming above a semiconductor substrate a capacitor element including a lower electrode, a capacitor insulation film formed on the lower electrode and an upper electrode formed on the capacitor insulation film, the method comprising: the steps of forming a lower shield layer with plurality of holes formed in and forming a lower electrode lead-out interconnection layer with a plurality of holes formed in, before the step of forming the capacitor element, and the steps of forming an upper electrode lead-out interconnection layer with a plurality of holes formed in and forming an upper shield layer with a plurality of holes formed in, after the step of forming the capacitor element.
As described above, according to the present invention, the shield layers are formed above and below the MIM capacitor, whereby combination of noises with the MIM capacitor can be prevented.
According to the present invention, the lower shield layer, the lower electrode lead-out interconnection layer, the lower electrode lining interconnection layer, the upper electrode lead-out interconnection layer and the upper shield layer are all meshed, which can prevent combination of noises with the MIM capacitor while the required design rules being satisfied.
According to the present invention, the mesh-pattern of the lower shield layer and the mesh-pattern of the lower electrode lead-out interconnection layer are offset from each other in their relative positional relationship, whereby a parasitic capacity between the lower shield layer and the lower electrode lead-out interconnection layer can be made very small. According to the present invention, the mesh-pattern of the upper electrode lead-out interconnection layer and the mesh-pattern of the upper shield layer are offset from each other in their relative positional relationship, whereby a parasitic capacity between the upper electrode lead-out interconnection layer and the upper shield layer can be made very small. Thus, according to the present invention, a parasitic capacity is prohibited from affecting electric characteristics.
According to the present invention, the insulation film is formed in a height substantially equal to the upper surface of the MIM capacitor around the MIM capacitor, whereby the surface of the inter-layer insulation film is prevented from rising above the MIM capacitor, and the surface of the inter-layer insulation film can be generally at a uniform height. Accordingly, the surface of the inter-layer insulation film can be planarized by CMP, and the upper electrode lead-out interconnection layers can be buried in the inter-layer insulation films, etc. by damascene method. Accordingly, in the present invention, Cu, etc. can be used as materials of the upper electrode lead-out interconnection layers, etc.
According to the present invention, the upper electrode lead-out interconnection layer can be buried in the inter-layer insulation film having the surface planarized, whereby the upper electrode lead-out interconnection layer is prevented from breaking, etc., and high reliability can be obtained.
According to the present invention, the inter-layer insulation film, etc. can be formed on the MIM capacitor, whereby the MIM capacitor can be formed without being limited to a vicinity of the uppermost layer.
According to the present invention, the M
Matsubara Daisuke
Yamauchi Hideaki
Armstrong Westerman & Hattori, LLP
Fujitsu Limited
Nguyen Cuong Quang
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