JPH08274164A - Semiconductor device - Google Patents

Abstract

PURPOSE: To secure an excellent coverage of conducing wiring layers with a second insulation film in a connecting hole regardless of the thickness of the film, easily connect the wiring layers to each other with low resistance, and prevent the deterioration of the reliability of the connecting sections of the wiring layers and the occurrence of discontinuity by providing a columnar structure below the lower wiring layer of the connecting hole section between the wiring layers. CONSTITUTION: A semiconductor device has a first insulating film 104, a lower conducting wiring layer 102, a second insulating film 103, and an upper conducting wiring layers 101 successively formed on the surface of a semiconductor substrate, and a connecting hole for connecting the upper and lower wiring layers 101 and 102. In this semiconductor device constituted in such a way, the connecting hole section between the wiring layers 101 and 102 has columnar structures 105 above the wiring layer 104 and below the wiring layer 102. For example, the wiring layer 102 is formed by removing the unnecessary part of an Al alloy film formed on the columnar structure 105 by sputtering after the structure 105 is formed on the first insulating film 104 of a conductive material or insulator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to connection between conductive wirings.

[0002]

2. Description of the Related Art A conventional semiconductor device is shown in FIG. That is, the upper conductive wiring 903 formed on the first insulating film 901 on the semiconductor substrate by the sputtering method, the second insulating film 902 formed thereon, and the upper conductive film formed on the 902 by the sputtering method. The wiring 903 has a connection hole portion for connecting the conductive wirings of the two layers, and the connection hole portion is formed on the upper layer from the hole reaching the lower conductive wiring 904 opened in the second insulating film 902. Conductive wiring 903
Is formed, and the upper conductive wiring 903 has a convex shape downward, so that the upper conductive wiring 903 and the lower conductive wiring 904 are formed.
Was the structure to be connected.

The above is the conventional semiconductor device.

[0004]

However, in the above-mentioned conventional technique, the aspect ratio, which is the ratio of the height to the diameter of the connection hole, increases as the thickness of the second insulating film 902 increases. The upper conductive layer 903
, The coverage of the connection hole is reduced. For this reason, it is difficult to form a low resistance inter-wiring connection, resulting in a decrease in reliability and a disconnection at the connection portion. Therefore, it is difficult to reduce the wiring capacitance because the second insulating film cannot be thickened.

Therefore, the present invention solves such a problem, and an object thereof is to ensure the coverage of the wiring in the connection hole irrespective of the thickness of the second insulating film. A first insulating film on a semiconductor substrate that facilitates formation of resistive interconnections, does not reduce reliability at connection portions, does not cause disconnection, etc., and can thicken the second insulating film to reduce wiring capacitance. An object of the present invention is to provide a semiconductor device having upper and lower conductive wirings sandwiching a second insulating film formed thereabove and a connection hole for connecting the conductive wirings of the two layers.

[0006]

In order to solve the above-mentioned problems, a semiconductor device of the present invention has a conductive wiring in upper and lower layers sandwiching a second insulating film formed on a first insulating film on a semiconductor substrate. And a semiconductor device having a connection hole for connecting the conductive wirings of the two layers, wherein the semiconductor device has a columnar structure below the lower layer wiring in the connection hole portion between the conductive wirings. The structure.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The semiconductor device of the present invention basically has the structure shown in FIGS. 1 (a) and 1 (b). FIG.
FIG. 1B is a sectional view taken along the line AB of FIG. 1
Reference numeral 01 is an upper conductive wire, 102 is a lower conductive wire, 103 is a second insulating film, and 104 is a first insulating film. Reference numeral 105 denotes a connection hole columnar structure, and by forming 102 thereon, upper and lower wirings 101 and 1 sandwiching the second insulating film 103 are formed.
02 is connected. 2 to 6 are main cross-sectional views of each step of the present invention. Hereinafter, description will be made in order with reference to FIGS. 2 to 6.

As shown in FIG. 2, the first insulating film 2 is formed on the semiconductor substrate.
01 is formed, and a connection hole portion columnar structure forming film 202 is formed on 201.
To form. The 202 is formed with a thickness of 0.5 μm to 3 μm. It is desirable that the film thickness of 202 is formed thick in order to reduce the wiring capacitance, but it is difficult to unnecessarily increase the film thickness in view of the depth of focus at the time of photo of the upper conductive wiring.
It is particularly desirable that the thickness be from μm to 1.2 μm. Next, as shown in FIG. 3, an unnecessary portion of 202 is removed by a photo and etching method, and a portion of the inter-wiring connection hole is left in a pillar shape. This becomes the connection hole portion columnar structure 203.

Thereafter, as shown in FIG. 4, an Al alloy film is formed by sputtering. The Al alloy film has a thickness of 0.5 μm to 1.
The thickness is about 5 μm. An unnecessary portion of the Al alloy film is removed by photo and etching methods, and this becomes the lower layer conductive wiring 204.

Next, as shown in FIG. 5, a Si oxide film to be the second insulating film 205 is deposited on the entire surface by chemical vapor deposition (CVD) by about 0.5 μm to 3 μm. Thereafter, the Si oxide film is entirely etched until 204 on 203 appears on the surface. It is desirable to flatten the Si oxide film before etching. For example, applying organic SOG 205
In addition, there are methods such as etch back and CMP (Chemical Mechanical Polishing). Then, as shown in FIG. 6, Al is sputtered.
An alloy film is formed. The Al alloy film is formed to a thickness of about 0.5 μm to 1.5 μm, and unnecessary portions of the Al alloy film are removed by a photo and etching method to form the upper conductive wiring 206. 2 is a method of manufacturing a semiconductor device according to the embodiment.

By forming the conductive wiring connecting portion as in the first embodiment, the coverage of the conductive wiring formed by sputtering in the connection hole is ensured regardless of the thickness of the second insulating film. And facilitates formation of low-resistance interconnections,
This facilitates the manufacture of a semiconductor device having a conductive interconnection connecting hole that does not cause a decrease in reliability or disconnection at the connecting portion.
Further, the second insulating film can be thickened to reduce the wiring capacitance.

FIGS. 7A and 7B are main sectional views of a semiconductor device according to the second embodiment of the present invention. A method of manufacturing a semiconductor device according to the second embodiment of the present invention will be described step by step.

An insulating film 701 is formed on the semiconductor substrate by CVD.
To form. 701 is formed to have a thickness not less than the sum of the thickness required for the first insulating film and the thickness of the second insulating film. Next, a columnar structure is formed as shown in FIG. 7B by photo and etching methods.

From this point onward, the manufacturing process is carried out in the same manner as in FIG.

The above manufacturing process is the manufacturing method of the semiconductor device of the second embodiment of the present invention.

By forming the conductive wiring connection portion as in the second embodiment, the coverage of the conductive wiring formed by sputtering in the connection hole is ensured regardless of the thickness of the second insulating film. And facilitates formation of low-resistance interconnections,
This facilitates the manufacture of a semiconductor device having a conductive interconnection connecting hole that does not cause a decrease in reliability or disconnection at the connecting portion.
Further, the second insulating film can be thickened to reduce the wiring capacitance.

Further, the first insulating film and the film having the columnar structure of the connection hole can be formed at the same time, and the number of steps can be reduced.

FIG. 8 is a main sectional view of a semiconductor device according to the third embodiment of the present invention. The method of manufacturing a semiconductor device according to the third embodiment of the present invention is the same as that of the first embodiment.

As in the third embodiment, by forming the conductive wiring connecting portion in the same manner as in the first embodiment, the coverage of the connection hole of the conductive wiring formed by sputtering can be improved by the second insulating film. It can be secured regardless of the thickness, facilitates formation of low-resistance wiring-to-wiring connections, and does not reduce reliability at the connection part, does not cause disconnection, etc. become. Further, the second insulating film can be thickened to reduce the wiring capacitance.

FIG. 10 is a main sectional view of a semiconductor device according to the fourth embodiment of the present invention. The semiconductor device manufacturing method according to the fourth embodiment of the present invention is the same as that of the connection hole portion columnar structure 1
It is similar to the first embodiment except that 5 is made of a conductive material.

By forming the conductive wiring connecting portion as in the fourth embodiment, the coverage of the conductive wiring formed by sputtering in the connection hole is ensured regardless of the thickness of the second insulating film. Therefore, it is easy to form a low-resistance inter-wiring connection, and it is easy to manufacture a semiconductor device having a conductive inter-wiring connection hole that does not cause a decrease in reliability at a connection portion or a disconnection. Further, the second insulating film can be thickened to reduce the wiring capacitance. Further, by forming the connection hole columnar structure with a conductive material, it is possible to further reduce the resistance of the conductive wiring connection portion.

Although the invention made by the present inventor has been described with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and may be modified without departing from the scope of the invention. Of course. For example, the same effect can be obtained by a method other than sputtering, such as CVD or plating, for the conductive wiring material, and also for metals such as Au, Ag, and Cu other than Al alloy or alloys thereof, and other conductive materials. It is the same. Further, for example, it is also effective when an insulating material other than Si oxide such as Si nitride is used for the first and second insulating films.

[0023]

According to the present invention, the coverage of the wiring in the conductive wiring indirect hole can be ensured irrespective of the thickness of the second insulating film, and the formation of a low-resistance interwiring connection can be facilitated. West,
The connection between the conductive wirings can be performed without lowering the reliability of the connection portion or causing the disconnection.

[Brief description of drawings]

FIG. 1 is a main drawing showing a first embodiment of a semiconductor device of the present invention.

FIG. 2 is a main sectional view for explaining a first embodiment of a method for manufacturing a semiconductor device of the present invention in the order of steps.

FIG. 3 is a main sectional view for explaining a first embodiment of a method for manufacturing a semiconductor device of the present invention in the order of steps.

FIG. 4 is a main sectional view for explaining a first embodiment of a method for manufacturing a semiconductor device of the present invention in the order of steps.

FIG. 5 is a main cross-sectional view for explaining the first embodiment of the method for manufacturing a semiconductor device of the present invention in the order of steps.

FIG. 6 is a main sectional view for explaining a first embodiment of a method for manufacturing a semiconductor device of the present invention in the order of steps.

FIG. 7 is a main cross-sectional view for explaining the second embodiment of the method for manufacturing a semiconductor device of the present invention.

FIG. 8 is a main sectional view for explaining a third embodiment of the method for manufacturing a semiconductor device of the present invention.

FIG. 9 is a main cross-sectional view showing an example of a conventional semiconductor device.

FIG. 10 is a main cross-sectional view for explaining the fourth embodiment of the method for manufacturing the semiconductor device of the present invention.

[Explanation of symbols]

 101 Upper Conductive Wiring 102 Lower Conductive Wiring 103 Second Insulating Film 104 First Insulating Film 105 Connection Hole Column Structure 201 First Insulating Film 202 Connection Hole Column Structure Forming Film 203 Connection Hole Column Structure 204 Lower Conduction Wire 205 Second Insulating film 206 Upper conductive wiring 701 Insulating film 801 Upper conductive wiring 802 Lower conductive wiring 803 Second insulating film 804 First insulating film 805 Connection hole columnar structure 901 First insulating film 902 Second insulating film 903 Upper conductive wiring 904 Lower conductive Wiring 801 Upper conductive wiring 802 Lower conductive wiring 803 Second insulating film 804 First insulating film 805 Connection hole columnar structure

Claims (7)

[Claims] 1. A lower-layer conductive wiring formed on a first insulating film on a semiconductor substrate, a second insulating film formed on the lower-layer conductive wiring, an upper-layer conductive wiring formed on the second insulating film, and In the semiconductor device having a connection hole for connecting the upper and lower conductive wires, the connection hole portion between the conductive wires has a columnar structure on the first insulating film and under the lower wiring. A semiconductor device characterized by the above. 2. The semiconductor device according to claim 1, wherein the columnar structure is the same layer as the first insulating film. 3. The semiconductor device according to claim 1, wherein the columnar structure is a layer different from the first insulating film. 4. The semiconductor device according to claim 1, wherein the columnar structure has the same height as the film thickness of the first insulating film. 5. The semiconductor device according to claim 1, wherein the columnar structure has a thickness higher than that of the first insulating film. 6. The semiconductor device according to claim 3, wherein the columnar structure is made of a conductive material. 7. The semiconductor device according to claim 3, wherein the columnar structure is made of an insulating material.