JPH08293645A - Multilayer interconnection structure - Google Patents

Abstract

PURPOSE: To provide a multilayer interconnection structure, wherein a thick insulating film is formed on the upper surface of a substrate and with a wiring formed on the side surface of this thick insulating film, an air bridge is provided so that it is formed in such a way as to extend along this wiring and with the strength of the substrate to a force from over the substrate improved, a wiring space is reduced and the constitution of the whole integrated circuit is contrived to miniaturize. CONSTITUTION: A thick insulating film 30 is formed on the upper surface of a substrate 10, a wiring 12 is formed on the side surface 30a of the film 30, an air bridge 32, which has a prescribed gap 20 between the wiring 12 and the air bridge 32 and at the same time, is extended along the vertical directions to the side surface 30a of the film 30, is formed and with the end part 32b of the bridge 32 made to position on the side of the upper surface of the film 30, the end part 32a of the bridge 32 ia made to position on the side of the substrate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a multilayer wiring structure,
More specifically, a monolithic microwave integrated circuit (Monol) that is used in the field of communication, including a resistor, an inductor, or a capacitor as a constituent element, is used.
itic Microwave Integrate
d Circuit: MMIC) and microwave IC (M
The present invention relates to a multilayer wiring structure suitable for use in an integrated circuit for microwave such as IC).

[0002]

2. Description of the Related Art In general, microwave integrated circuits such as MMIC and MIC include resistors, inductors or capacitors as constituent elements, and the above-mentioned resistors, inductors or capacitors are constructed by a multilayer wiring structure. Has been done.

FIG. 6 shows a conventional multilayer wiring structure in the case where an inductor or the like is formed in such an integrated circuit for microwaves, without contacting the wiring 12 formed on the upper surface of the substrate 10. The wiring 14 and the wiring 1 formed on the upper surface of the substrate 10 so as to sandwich the wiring 12 therebetween.
In order to establish electrical connection with the wiring 6, the wiring 14 and the wiring 16 are connected by the air bridge (aerial wiring) 18.

That is, the wiring 12 is crossed,
While maintaining a predetermined gap 20 between the wiring 12,
A bridge 18 is formed so as to connect the wiring 14 and the wiring 16. The air bridge 18 has a rising portion 18a rising from the wiring 14 and the wiring 16, respectively, and a predetermined portion along the substrate 10 and the wiring 12. Each rising portion 18 while extending with a gap 20 of
It was composed of a bridge portion 18b connecting a.

[0005]

However, in the conventional integrated circuit having the multilayer wiring structure shown in FIG.
Air bridge 18 crossing over wiring 12
4 and the rising portion 18a rising from the wiring 16 respectively, and the bridge portion 18b extending along the substrate 10 with the wiring 12 at a predetermined gap 20 and connecting the rising portions 18a, the substrate 10 The force F from above causes the bridge portion 18b of the air bridge 18 to be easily deformed and crushed downward.
There is a problem that the bridge portion 18b of the bridge 18 and the wiring 12 come into contact with each other to cause a short circuit.

That is, in the conventional multilayer wiring structure, for example, when the integrated circuit is attracted to the collet portion of the automatic mounter during mounting, the force F from above the substrate 10 is applied to the air bridge 18. If such a force F is applied to the bridge portion 18b of the air bridge 18, the bridge portion 18b of the air bridge 18 may be crushed downward, and the force F applied from above the substrate 10 may be applied. It was pointed out that the strength was weak.

Further, in the conventional multi-layer wiring structure, since the wiring 12 and the bridging portion 18b are formed along the substrate 10, the wiring space occupied by the wiring 12 and the bridging portion 18b on the substrate 10 is reduced. There is a problem in that the size of the integrated circuit becomes large and the size of the entire integrated circuit becomes large.

The present invention has been made in view of the above-mentioned various problems of the prior art. The purpose of the present invention is to form a thick insulating film on the upper surface of a substrate, Wiring is formed on the side surface of the insulating film, and an air bridge is formed along this wiring,
While improving the strength against the force from above the substrate,
It is an object of the present invention to provide a multi-layer wiring structure in which the wiring space can be reduced and the structure of the entire integrated circuit can be downsized.

[0009]

In order to achieve the above object, a multilayer wiring structure according to the present invention is a multilayer wiring structure of an integrated circuit in which a plurality of wirings are formed on a substrate. And forming a first wiring on a side surface of the thick film insulating film, and having a predetermined gap with the first wiring and extending along a vertical direction of a side surface of the thick film insulating film. A wiring is formed so that one end of the second wiring is located on the upper surface side of the thick film insulating film and the other end of the second wiring is located on the substrate side. Is.

[0010]

The second wiring has a predetermined gap with the first wiring formed on the side surface of the thick film insulating film and is formed so as to extend along the vertical direction of the side surface of the thick film insulating film. Therefore, the strength of the second wiring with respect to the force applied from the upper surface of the substrate can be improved, and even if the second wiring is deformed by the force applied from the upper surface of the substrate, the second wiring and the first wiring It becomes difficult to contact with and the short circuit due to the contact between the second wiring and the first wiring can be prevented.

Since the first wiring and the second wiring are not formed along the substrate but along the side surface of the thick film insulating film, the wiring space on the substrate can be reduced. Become.

[0012]

Embodiments of the multilayer wiring structure according to the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows a sectional view of a first embodiment of a multilayer wiring structure according to the present invention. In the following description with reference to FIG. 1 to FIG. 5, in order to facilitate understanding of the present invention, the same or corresponding configuration as that of the conventional technique shown in FIG. Will be shown using.

That is, the multilayer wiring structure shown in FIG.
A thick film insulating film 30 having a substantially trapezoidal cross section is formed on the surface.
Further, the wiring 12 is formed on the side surface 30a of the thick insulating film 30, the wiring 14 is formed on the upper surface of the substrate 10, and the wiring 16 is formed on the upper surface 30b of the thick insulating film 30.

Then, one end 32a is connected to the wiring 14 formed on the upper surface of the substrate 10, and the other end 32 is formed.
b is the wiring 16 formed on the upper surface 30b of the thick insulating film 30.
The air bridge 32 is formed so as to extend along the vertical direction of the side surface 30a of the thick film insulating film 30 while having a predetermined gap 20 with the wiring 12.

The air bridge 32 rises from the end 32a connected to the wiring 14 formed on the upper surface of the substrate 10 and also connected to the wiring 16 formed on the upper surface 30b of the thick insulating film 30. The bridging portion 32c is formed so as to fall from 32b, and the bridging portion 32c is arranged substantially parallel to the wiring 12 formed on the side surface 30a of the thick insulating film 30 with a predetermined gap 20.

Therefore, the wiring 12 and the air bridge 32
The bridging portion 32c of the substrate 10 is arranged so as not to extend in the direction along the upper surface of the substrate 10 but to extend in the upward direction of the substrate 10, and thus the bridging portion 32c against the force F from above the substrate 10. The intensity of.

Therefore, the substrate 1 is attached to the air bridge 32.
Even if a force F is applied from the upper surface of 0, the bridge portion 32c is not easily deformed, and a short circuit due to contact between the air bridge 32 and the wiring 12 can be prevented.

Further, if the force F applied from the upper surface of the substrate 10 is assumed.
Even if the air bridge 32 is deformed so as to project downward due to, the bridge portion 3 between the wiring 12 and the air bridge 32
Since 2c is arranged so as to extend in the upward direction of the substrate 10, it is difficult for the air bridge 32 and the wiring 12 to come into contact with each other, and a short circuit due to the contact between the air bridge 32 and the wiring 12 can be prevented.

Further, the wiring 12 and the air bridge 32 are bridged so as not to extend in the direction along the upper surface of the substrate 10 but to extend upward in the substrate 10 along the side surface 30a of the thick insulating film 30. Since the portion 32c is arranged, the wiring space on the substrate 10 can be remarkably reduced as compared with the conventional multilayer wiring structure, and the configuration of the entire integrated circuit can be downsized. Become.

FIG. 2 is a sectional view of the second embodiment of the multilayer wiring structure according to the present invention. In the point that the dielectric layer 40 is provided in the gap 20, the above-mentioned first embodiment is used.
Is different from the embodiment described above.

Therefore, according to the second embodiment, an inductor having a large strength against the force F from above the substrate 10 and a small wiring space can be formed on the substrate 10.

Further, FIG. 3 shows a cross-sectional view of a third embodiment of the multilayer wiring structure according to the present invention, which is described above in that the polyimide layer 50 is formed as the dielectric layer 40 provided in the gap 20. Different from the second embodiment.

That is, as the dielectric film 40, the polyimide film 50 or the like can be appropriately selected and used.

Furthermore, FIG. 4 shows a cross-sectional view of a fourth embodiment of the multi-layer wiring structure according to the present invention.
On the two side surfaces of the thick insulating film 30 formed above,
An example in which a multilayer film structure according to the present invention is implemented is shown.

That is, the wiring 12 is formed on the side surface 30a of the thick film insulating film 30, and the wiring 60 is formed on the side surface 30c of the thick film insulating film 30.
To form a predetermined gap 2 with these wirings 12, 60.
Air bridges 32, 62 are formed to have zeros. The upper end portion 62a of the air bridge 62 is
Is connected to the wiring 16, and the lower end portion 62b of the air bridge 62 is connected to the wiring 64 formed on the substrate 10.

FIG. 5 shows a spiral inductor constructed by using a multilayer wiring structure according to the first embodiment of the present invention.

That is, by using the multilayer wiring structure according to each of the above-described embodiments of the present invention, an inductor or the like having high strength and a reduced wiring space is provided on the substrate 10.
Be able to configure on.

[0029]

Since the multilayer wiring structure according to the present invention is constructed as described above, the strength against the force from above the substrate can be improved and the wiring space can be reduced and integrated. This has an excellent effect of reducing the size of the entire circuit.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a multilayer wiring structure according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the multilayer wiring structure according to the present invention.

FIG. 3 is a sectional view showing a third embodiment of the multilayer wiring structure according to the present invention.

FIG. 3 is a sectional view showing a fourth embodiment of the multilayer wiring structure according to the present invention.

FIG. 5 is a cross-sectional view showing a spiral inductor formed by using a multilayer wiring structure according to a first embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a conventional multilayer wiring structure.

[Explanation of symbols]

 10 substrate 12, 14, 16 wiring 18, 32 air bridge 18b, 32c bridge portion of air bridge 20 gap 30 thick film insulating film 30a, 30c side face of thick film insulating film 32a, 32b end of air bridge 40 dielectric Body layer 50 Polyimide layer

Claims (3)

[Claims] 1. In a multilayer wiring structure of an integrated circuit having a plurality of wirings formed on a substrate, a thick film insulating film is formed on a top surface of the substrate, and a first wiring is formed on a side surface of the thick film insulating film, A second wiring having a predetermined gap with the first wiring and extending along the vertical direction of the side surface of the thick film insulating film is formed, and one end of the second wiring is connected to the thick film insulating film. A multi-layer wiring structure characterized in that it is positioned on the upper surface side of the film, and the other end of the second wiring is positioned on the substrate side. 2. The multilayer wiring structure according to claim 1, wherein
A multilayer wiring structure characterized in that a dielectric is provided in the gap. 3. The multilayer wiring structure according to claim 2, wherein the dielectric is a polyimide layer.