SEMICONDUCTOR DEVICE, RF-IC AND MANUFACTURING METHOD OF THE SAME
Provided is a technology capable of reducing parasitic capacitance of a capacitor while reducing the space occupied by the capacitor. A stacked structure is obtained by forming, over a capacitor composed of a lower electrode, a capacitor insulating film and an intermediate electrode, another capacitor composed of the intermediate electrode, another capacitor insulating film and an upper electrode. Since the intermediate electrode has a step difference, each of the distance between the intermediate electrode and lower electrode and the distance between the intermediate electrode and upper electrode in a region other than the capacitor formation region becomes greater than that in the capacitor formation region. For example, the lower electrode is brought into direct contact with the capacitor insulating film in the capacitor formation region, while the lower electrode is not brought into direct contact with the capacitor insulating film in the region other than the capacitor formation region.
1 . A semiconductor device for processing a radio frequency (RF) signal, including a capacitor, the capacitor comprising:
a lower electrode of the capacitor made of a metal film;
a first interlayer insulating film having a first opening portion formed over the lower electrode, a top surface of said lower electrode being exposed from the first interlayer insulating film through the first opening portion, and said lower electrode being partially covered by the first interlayer insulating film;
a first capacitor insulating film of the capacitor formed continuously over the first interlayer insulating film and inside the first opening portion;
an intermediate electrode of the capacitor made of a metal film formed over the first capacitor insulating film, said first intermediate electrode being formed inside and outside the first opening portion;
a second interlayer insulating film having a second opening portion formed over the intermediate electrode, a top surface of said intermediate electrode being exposed from the second interlayer insulating film through the second opening portion;
a second capacitor insulating film of the capacitor formed continuously over the second interlayer insulating film and inside the second opening portion;
an upper electrode of the capacitor made of a metal film formed over the second capacitor insulating film, said upper electrode being formed inside and outside the second opening portion;
a first conductor film in a first contact hole formed in the first and second interlayer insulating film, said first conductor film electrically connecting the upper and lower electrodes;
a second conductor film in a second contact hole formed in the second interlayer insulating film, said second contact hole positioned right above the first interlayer insulating film; and
an interconnecting wiring formed over the second interlayer insulating film, said interconnecting wiring and intermediate electrode being electrically connected via the second conductor film.
2 . A semiconductor device according to claim 1 ,
wherein the semiconductor device includes a low noise amplifier (LNA) for amplifying the RF signal, and
wherein the capacitor is electrically coupled to an input portion of the LNA.
3 . A semiconductor device according to claim 2 ,
wherein the capacitor is used for an impedance matching circuit.
4 . A semiconductor device according to claim 1 ,
wherein the semiconductor device includes a low noise amplifier LNA for amplifying the RF signal,
wherein the semiconductor device includes a programmable gain amplifier (PGA) with a bandpass filter,
wherein an output portion of the LNA is electrically coupled to an input portion of the PGA, and
wherein the capacitor is used in the bandpass filter.
5 . A semiconductor device according to claim 1 ,
wherein the semiconductor device includes a voltage controlled oscillator (VCO), and
wherein the capacitor is used in the VCO.
6 . A semiconductor device according to claim 5 ,
wherein the VCO is a differential type oscillator composed of an amplifier circuit for applying a negative resistance and LC resonance circuit.
7 . A semiconductor device according to claim 1 ,
wherein the first capacitor insulating film is contacted with the top surface of the lower electrode; and
the second capacitor insulating film is contacted with the top surface of the intermediate electrode.
8 . A semiconductor device according to claim 1 ,
wherein the first interlayer insulating film exists between a part of the intermediate electrode formed outside the first opening portion and a top surface of the lower electrode.
9 . A semiconductor device according to claim 1 ,
wherein the first interlayer insulating film exists between a part of the first capacitor insulating film formed outside the first opening portion and a top surface of the lower electrode.
10 . A semiconductor device according to claim 1 ,
wherein an area of the first opening portion is greater than that of the second opening portion.
11 . A semiconductor device according to claim 1 ,
wherein the first capacitor insulating film is comprised of a silicon oxide film or a silicon nitride.
12 . A semiconductor device according to claim 1 ,
wherein the first capacitor insulating film is comprised of an aluminum oxide film, a tantalum oxide film or a hafnium oxide film.
13 . A semiconductor device according to claim 1 ,
wherein the lower, intermediate and upper electrodes are comprised of aluminum films.
14 . A semiconductor device according to claim 1 ,
wherein the upper electrode and the interconnecting wiring are formed in a same layer.
15 . A semiconductor device for processing a radio frequency (RF) signal, including a low noise amplifier (LNA) for amplifying the RF signal, a programmable gain amplifier (PGA) for amplifying an output of the LNA and a voltage controlled oscillator (VCO) each of which has a capacitor,
the capacitor comprising:
a lower electrode of the capacitor made of a metal film;
a first interlayer insulating film having a first opening portion formed over the lower electrode, a top surface of said lower electrode being exposed from the first interlayer insulating film through the first opening portion, and said lower electrode being partially covered by the first interlayer insulating film;
a first capacitor insulating film of the capacitor formed continuously over the first interlayer insulating film and inside the first opening portion;
an intermediate electrode of the capacitor made of a metal film formed over the first capacitor insulating film, said first intermediate electrode being formed inside and outside the first opening portion;
a second interlayer insulating film having a second opening portion formed over the intermediate electrode, a top surface of said intermediate electrode being exposed from the second interlayer insulating film through the second opening portion;
a second capacitor insulating film of the capacitor formed continuously over the second interlayer insulating film and inside the second opening portion;
an upper electrode of the capacitor made of a metal film formed over the second capacitor insulating film, said upper electrode being formed inside and outside the second opening portion;
a first conductor film in a first contact hole formed in the first and second interlayer insulating film, said first conductor film electrically connecting the upper and lower electrodes;
a second conductor film in a second contact hole formed in the second interlayer insulating film, said second contact hole positioned right above the first interlayer insulating film; and
an interconnecting wiring formed over the second interlayer insulating film, said interconnecting wiring and intermediate electrode being electrically connected via the second conductor film.