JPH0637251A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device of a structure, wherein a chip size is made small and at the same time, the degree of freedom of layout of elements can be improved, and moreover, having superior high-frequency characteristics. CONSTITUTION:Active elements are formed on the surface of a semiconductor substrate 1, a plurality of kinds of passive elements are respectively formed on the active elements via insulating films 5, 8 and 14 in a multilayer and the passive elements 7, 10 and 16 are different from each other in kind in each layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device. More specifically, the present invention relates to a semiconductor device such as a microwave integrated circuit in which a large number of capacitors and inductors are incorporated in a circuit, which can reduce the chip size and improve the degree of freedom in element layout.

[0002]

2. Description of the Related Art As shown in FIG. 2, an MMIC (Monolithic Microwave IC) which mainly performs signal processing in a microwave band is formed on a semi-insulating semiconductor substrate such as GaAs on a field effect transistor (hereinafter referred to as a high frequency amplifier). FE
T) and Schottky barrier diode for detection, and resistors (semiconductor resistors) are formed, and circuit elements such as transmission lines, capacitors, and inductors are formed on the surface of the substrate through an insulating film, and monolithically integrated. It is a converted microwave circuit. In this MMIC, the FET,
Diodes and the like are dispersed and arranged on one plane.

By the way, it is necessary to form only a FET, a diode and a semiconductor resistor on a semiconductor substrate such as a GaAs substrate or a Si substrate, but in the conventional MMIC, other inductors, capacitors and the like are also wired with the FET and the like. Since a circuit must be formed by connecting with each other, it is formed on the surface of the semiconductor substrate on which the FET and the like are not formed, via an insulating film.

[0004]

In the conventional MMIC, since all the circuit elements are formed in a plane as described above, there is a problem that the chip area becomes large and the degree of freedom of element layout is low. In addition, since the circuit elements are formed on the same plane, the connection wiring between the elements also needs to be laid out on the substrate, and a long wiring is formed. In the microwave band, even if the wiring becomes a little longer, the inductance increases and adversely affects the characteristics.In addition, capacitance is formed between the wirings, and the characteristics are affected by mutual interference, etc., so the wiring should be as short as possible. There is also the problem of having to do so.

In view of the above circumstances, the present invention provides a semiconductor device capable of reducing the chip area to improve the degree of freedom of element layout and forming a compact circuit which does not adversely affect the operating characteristics. The purpose is to do.

[0006]

The semiconductor device of the present invention comprises:
An active element is formed on the surface of a semiconductor substrate, a plurality of types of passive elements are formed in multiple layers on the surface of the semiconductor substrate through an insulating film, and the passive elements are different in type for each layer. There is.

[0007]

According to the present invention, since the passive element which does not require the semiconductor layer is formed on the surface of the semiconductor substrate on which the active element is formed via the insulating film, the distance between the elements can be reduced. Shorter connection wiring nearby. As a result, it is possible to prevent mutual interference due to connection wiring, noise pickup, stray capacitance, inductance generation, etc., which are particularly problematic at high frequencies, and high frequency characteristics are improved.

[0008]

The semiconductor device of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional explanatory view of an embodiment of the semiconductor device of the present invention.

In FIG. 1, reference numeral 1 is a semiconductor substrate such as a GaAs substrate or a Si substrate, and the front side of the substrate 1 is FE.
T2, a diode (not shown) and a semiconductor resistor 4 are formed, each electrode is further formed on the surface, and necessary wiring 2
a, 2b, 4a, 4b are performed. FET2 is Si
In the case of a substrate, a gate electrode is formed on the surface via an insulating film, and an impurity region having a conductivity type different from that of the semiconductor layer is formed on both sides of the gate electrode to form a source / drain region. Can be formed by forming an impurity-containing semiconductor layer on the surface of a semi-insulating substrate such as and forming source, gate, and drain electrodes on the surface, and a diode can be formed on a semiconductor layer such as GaAs by Ti. It can be formed by directly coating a metal material such as / Pt / Au or Al to form a Schottky barrier diode or forming a pn junction. Further, the semiconductor resistor 4 can form a resistor having a desired resistance value by forming an impurity concentration layer having a low concentration on a semi-insulating semiconductor substrate.

Next, the first interlayer insulating film 5 made of SiO ₂ , SiN, SiON, etc. is subjected to thermal CVD and plasma CV.
D, a sputtering method or the like is deposited on the surface of the substrate 1 to form a contact hole in the obtained first interlayer insulating film 5. A contact metal or a via metal is embedded in the contact hole to form the first connection wiring 6. As the contact metal, Au, Ag, and C having high electric conductivity
It is preferable to use u or the like. The contact hole is formed, for example, by performing dry etching such as RIE or wet etching after forming the resist pattern. Then, a contact metal can be embedded in the obtained hole by vapor deposition or the like, and then a metal film other than the inside of the hole can be removed by etching or a lift-off method to form a connection wiring.

The thickness of the first interlayer insulating film 5 is the second
Similarly to the third interlayer insulating film, although not particularly limited in the present invention, the thickness is such that each electrode on the surface of the substrate is completely covered and the surface of the insulating film is substantially flat, and usually in the range of 1 to several μm. .

In addition to the semiconductor resistance, the resistance can be formed as a thin film resistance by coating a resistance material such as nichrome or forming polysilicon or the like and doping impurities.

Next, a thin film resistor 7 is formed on the first interlayer insulating film 5. Specifically, it can be formed by depositing nichrome or TaN so as to have a thickness of about 500 Å and a width of several to 10 μm by a sputtering method. Then, similarly to the first interlayer insulating film 5 and the first connecting wiring 6, respectively, the second interlayer insulating film 8 and the second connecting wiring 9 are formed.

Next, the capacitor 10 is formed on the second interlayer insulating film 8.
To form. Specifically, the lower electrode 11 having a three-layer structure of Ti, Pt, and Au is formed by a vapor deposition method or a sputtering method, and SiN or SiO ₂ is thermally CV-coated on the lower electrode 11.
About 1000 by D method, plasma CVD method, sputtering method, etc.
The dielectric film 12 is formed by depositing it with a thickness of Å. And
An upper electrode 13 is formed on the dielectric film 12 in the same manner as the lower electrode 11. Then, similarly to the first interlayer insulating film 5 and the first connection wiring 6, respectively, a third interlayer insulating film is formed.
14 and the third connection wiring 15 are formed.

Next, the inductor 16 is formed on the third interlayer insulating film 14. Specifically, A with high electrical conductivity
u, Ag, or Cu is deposited by evaporation or sputtering to have a thickness of several μm, and the inductor 16 is formed by etching or lift-off. If it is desired to increase the thickness, it may be formed by a plating method.

As described above, the first layer is formed with only a device required to manufacture a semiconductor layer such as GaAs or Si, the second layer is a thin film resistor, the third layer is a capacitor, and the fourth layer is an inductor. The elements to be manufactured are limited by the layers. The layers are separated from each other by an insulating film, and the upper and lower layers are connected to each other by using contact holes only in necessary portions. By forming the same type of element for each layer in this way, the manufacturing process of each layer can be made common, the manufacturing becomes easy, and the thickness of each layer becomes substantially uniform,
It is easy to form the upper layer element.

Although the thin film resistor is arranged in the second layer, the capacitor is arranged in the third layer, and the inductor is arranged in the fourth layer in the above-mentioned embodiment, the relationship between them is not limited in the present invention. Absent. Therefore, for example, a capacitor may be arranged in the second layer and a thin film resistor may be arranged in the third layer, that is, elements of different types may be arranged for each layer.

In the embodiment described above, the semiconductor substrate is a GaAs substrate or a Si substrate, but InP or the like may be used instead. In addition to the above-mentioned examples, the thin-film resistance material is a polysilicon film, Ta,
It can also be formed by using o or the like, and when it is formed by a semiconductor resistor, it is formed in the substrate, that is, the first layer. Furthermore, an insulating film can be formed on the surface of the uppermost layer on which the inductor and the like are formed.

In the above-mentioned embodiment, the connection wiring of the elements between the respective layers has been described as an example in which the contact holes are formed in the insulating films of the respective layers, but the connection wiring is led out to one end side of each layer and is connected at the end portion. It is also possible to make interconnections between the elements by interconnecting them.

Further, by forming a metal film such as aluminum on the boundary surface of each layer and connecting it to the ground, it is possible to prevent mutual interference between the layers and the influence of noise.

[0021]

As described above, in the semiconductor device of the present invention, only the elements that need to be formed directly on the semiconductor substrate are formed on the surface of the substrate, and the remaining passive elements such as capacitors and inductors are provided through the insulating film. Are formed on the substrate so as to have a multilayer structure. Therefore, the chip size can be reduced. Further, since the elements desired to be arranged close to each other on the circuit can be arranged vertically, the layout can be relatively freely performed.

Further, since the elements are arranged one above the other, the distance between the elements is very small and the connection wiring is short, so that it is not necessary to increase the wiring resistance, unnecessary inductance and capacitor, and to prevent the influence of mutual interference. It is possible to obtain a semiconductor device with less noise and good high frequency characteristics.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of an embodiment of a semiconductor device of the present invention.

FIG. 2 is an explanatory diagram of a conventional MMIC.

[Explanation of symbols]

 1 Semiconductor Substrate 2 FET 4 Semiconductor Resistor 5 First Interlayer Insulation Film 6 First Connection Wiring 7 Thin Film Resistor 8 Second Interlayer Insulation Film 9 Second Connection Wiring 10 Capacitor 14 Third Interlayer Insulation Film 15 Third Connection Wiring 16 Inductor

Claims (1)

[Claims] 1. An active element is formed on a surface of a semiconductor substrate, and a plurality of types of passive elements are formed in multiple layers on the surface of the semiconductor substrate with an insulating film interposed therebetween. A semiconductor device characterized by being different.