KR100396687B1 - Method for forming metal interconnection of semiconductor device - Google Patents

Abstract

PURPOSE: A method for forming a metal interconnection of a semiconductor device is provided to improve reliability of metallization by growing aluminum at high temperature. CONSTITUTION: The first metal film is formed on a semiconductor substrate. By selectively etching the first metal film, the first metal interconnection with a protrusion at contact portion is formed. An aluminum film(24) with a pillar shape is formed on the protrudent first metal interconnection by growing aluminum at high temperature. An insulating layer(25) is formed to expose the aluminum film on the resultant structure. Then, the second metal interconnection(26) is formed to connect the first metal interconnection through the aluminum film.

Description

Metal wiring formation method of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wiring of semiconductor integrated circuits, and more particularly, to a wiring forming method of a semiconductor device with improved interconnection between wirings.

In general, aluminum and its alloy thin films have high electrical conductivity and are excellent in pattern formation by dry etching. In addition, it has been widely used as a wiring material of a semiconductor circuit because of its excellent adhesion with a silicon oxide film and relatively low cost.

However, as the degree of integration of integrated circuits increases, the size of the device decreases and the wiring becomes finer and multilayered, so that step coverage within the portion having a topology, a contact hole, or a via hole is increased. This is an important issue.

That is, when the sputtering method, which is a conventional metal wiring film forming method, is used, the thickness of the wiring film is locally thinned due to the shadow effect in the vicinity of the curve.

In particular, it is more severe in connection holes having an aspect ratio of 1 or more.

Therefore, instead of the physical vapor deposition method, a chemical vapor deposition method capable of depositing a uniform thickness was introduced, and a study of improving step coverage by forming a tungsten film by a low pressure chemical vapor deposition method was performed.

However, since the tungsten wiring film has a resistivity twice or more than that of the aluminum wiring film, it is difficult to apply it as a wiring film.

Therefore, development as a method of forming a buried layer (plug) in the connection hole is in progress.

The buried layer is formed by selectively growing a tungsten film through a substrate exposed in a connection hole by applying a selective chemical vapor deposition method, or by forming a barrier metal film or an adhesive layer, and then depositing a tungsten film on the entire surface and etching it back to a deposition thickness or more. There is a way.

However, in such a selective growth method, it is not easy to maintain the growth on the insulating layer.

In the case of etching back after full deposition, it is necessary to form a reliable barrier layer or adhesive layer in a connection hole having a high aspect ratio.

To this end, a collimator or chemical vapor deposition (CVD) method should be used to ensure the minimum thickness of tungsten nucleation on the bottom or sidewall of the connection hole.

On the other hand, since the depth of the connection hole depends on the degree of planarization of the insulating layer, the surface of the connection hole and the surface of the buried layer are not substantially the same. (In general, the surface of the investment layer is lower.)

On the other hand, the formation of an aluminum-based wiring film by chemical vapor deposition improves the step coverage and at the same time maintains the continuity with the surrounding process of the aluminum wiring film technology by conventional sputtering such as photolithography and etching. So it is advantageous.

On the other hand, copper (copppr) has a lower specific resistance than aluminum, and excellent electrical property migration (stress migration) or stress migration (stress migration) characteristics can further improve the reliability. Therefore, a method of forming copper by sputtering or chemical vapor deposition has been studied.

However, when a halogen compound useful for etching aluminum is applied to copper etching, since the vapor pressure of the halogen compound is low, the operating temperature must be increased to about 500 ° C. in order to obtain an applicable etching ratio. Therefore, in the case of copper wiring, instead of etching patterning by etching, trenches are formed in the substrate in the form of wiring patterns.

After the copper is deposited, it is etched back by Chemical Mechanical Polishing (CMP) to form a buried conductive line or a vertical growth by using a lower conductive layer of a contact hole or a via hole as a seed. A method of selectively forming a plug through an attempt has been attempted.

As a method of forming a wiring by selectively depositing copper, a copper pattern is formed by selectively depositing copper on a seed layer using a TEOS oxide film pattern as a sacrificial film for wiring formation, removing the TEOS oxide film, and selectively etching the seed layer. Formed.

Hereinafter, a metal wire forming method of a conventional semiconductor device will be described with reference to the accompanying drawings.

1A to 1C are cross-sectional views illustrating a method of forming metal wirings in a conventional semiconductor device.

First, as shown in FIG. 1A, a first insulating layer 2 is formed on a semiconductor substrate 1, and a first metal wiring layer 3 is formed on the first insulating layer 2. A second insulating layer 4 is formed on the first metal wiring layer 3.

Subsequently, as shown in FIG. 1B, after the photoresist is deposited and patterned on the entire surface including the second insulating layer 4 to form the first photoresist pattern 5, the first photoresist pattern 5 is formed. The second insulating layer 4 is etched using a mask to form a contact hole 6 to expose a predetermined portion of the surface of the first metal wiring layer 3.

Subsequently, as shown in FIG. 1C, the second metal wiring layer 7 is formed on the second insulating layer 4 including the contact hole 6.

Here, the first and second metal wiring layers 3 and 7 are formed using a sputtering method of forcibly removing particles from a metal mass and forming them on an insulating film.

At this time, since more metal particles are deposited at the inlet of the contact hole 6, it becomes difficult for the metal particles to gradually enter the contact hole 6, so that the first and second metal layers are disposed on the sidewalls of the second insulating layer 4 and the first metal wiring layer 3. 2 The metal wiring layer 7 is formed thin.

However, the above-described conventional metal wiring forming method of the semiconductor device has the following problems.

When wires and wiring connections are connected through the contact holes, metal wire particles are formed at the contact hole entrances, thereby decreasing the entrances, thereby preventing the entry of metal particles into the contact holes. Therefore, when the connection wiring in the contact hole is thin and an overload occurs during the electrical operation of the semiconductor device, the wiring is broken and the semiconductor operation is stopped.

An object of the present invention is to provide a method for forming a metal wiring of a semiconductor device suitable for improving the reliability of wiring by growing aluminum at high temperature and connecting wiring and wiring at high temperature.

1A to 1C are cross-sectional views illustrating a method of forming metal wirings in a conventional semiconductor device.

2A to 2C are cross-sectional views illustrating a method of forming metal wirings in a semiconductor device of the present invention.

Explanation of symbols for main parts of the drawings

20 substrate 21 first insulating layer

22: first metal wiring layer 23: photoresist pattern

24: aluminum layer 25: second insulating layer

26: second metal wiring layer

In order to solve the above problems, the method for forming a metal wiring of the semiconductor device of the present invention comprises the steps of forming a first wiring layer having a contact portion of the contact portion on the substrate; Forming an insulating layer on the entire surface of the substrate except for the protrusions; And forming a second wiring layer on the insulating layer to be connected to the first wiring layer through the protrusion.

Hereinafter, a metal wiring forming method of a semiconductor device of the present invention will be described with reference to the accompanying drawings.

2A to 2C are cross-sectional views illustrating a method of forming metal wirings in a semiconductor device of the present invention.

As shown in FIG. 2A, a first insulating layer 21 is formed on the semiconductor substrate 20, and a first metal wiring layer 22 is formed on the first insulating layer 21. A photoresist pattern 23 is formed on the first metal wiring layer 22 by depositing and patterning the photoresist to expose a predetermined region of the first metal wiring layer 22.

Next, as shown in FIG. 2B, the exposed first metal wiring layer 22 is etched to a predetermined depth using the photoresist pattern 23 as a mask, and then the photoresist pattern 23 is removed. The aluminum layer 24 is formed on the first metal wiring layer 22 at a high temperature.

At this time, the aluminum layer 24 is formed around the nucleus of the first metal wiring layer 22 to form a pillar-shaped aluminum layer 24. Here, the aluminum particles are aggregated together to form pillars to minimize the surface tension around the nucleus by surface diffusion.

Subsequently, as illustrated in FIG. 2C, a second insulating layer 25 is formed to expose the surface of the pillar-shaped aluminum layer 24, and the pillar-shaped aluminum layer 24 is formed on the second insulating layer 25. The second metal wiring layer 26 is formed to be connected to the second metal wiring layer 26.

As described above, the metal wiring forming method of the semiconductor device of the present invention has the following effects.

First, since the wiring connecting the wiring to the wiring is a metal pillar having a certain thickness, the reliability of the wiring is good and the semiconductor life is extended.

Second, because the distance between the wiring and wiring and the size of the connection column can be adjusted, the connection between the wiring is easy.

Claims (1)

Depositing a wiring material on the substrate and selectively removing the wiring material to form a wiring pattern; Etching the wiring pattern excluding a contact portion to a predetermined thickness to form a first wiring layer to have a protrusion at the contact portion; Forming a columnar aluminum layer using the aluminum particles aggregated to minimize surface tension around the protrusion of the first wiring layer by surface diffusion; Forming an insulating layer on the entire surface of the substrate to expose the upper surface of the pillar-shaped aluminum layer; And forming a second wiring layer on the insulating layer to be connected to the first wiring layer through the pillar-shaped aluminum layer.