KR100294257B1 - Formation method of conductive plug - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a conductive plug, which forms a device having a conductive region on a semiconductor substrate. An insulating layer is formed on the semiconductor substrate and the insulating layer is etched to form a contact window exposing the conductive region of the device. A diffusion barrier layer is formed around the exposed conductive region and the contact window, hydrogen plasma treatment is performed in the reaction chamber, and then a conductive material is filled into the contact window to form a conductive plug.

Description

Formation method of conductive plug

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing process, and more particularly to a method for forming a conductive plug for suppressing generation of empty spaces.

Increasing the density of integrated circuits, the chip surface may not provide enough space for interconnects disposed thereon. Because of the need for interconnects of small size metal oxide semiconductor transistors, two or more metal layers have become essential in many integrated circuits. In some complex products, such as microprocessors, much more metal layers are needed to complete the interconnection between the individual devices in the microprocessor. Each metal layer is connected by a conductive plug.

The conductive plug is generally formed by etching the insulating layer to form a contact hole, and then filling a contact hole with a conductive metal such as tungsten. Since the adhesion between the conductive material and the insulating layer is not easy, a glue / barrier material must be formed between the conductive material and the insulating layer. Commonly used glue / barrier materials include Ti, TiN _x or TiW formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD).

However, conductive plugs in integrated circuits formed by conventional processes are easy to create empty spaces. In order to explain the reason more clearly, the following describes, for example, a conventional process of forming a conductive plug of an integrated circuit.

1 is a cross-sectional view of a conductive plug of an integrated circuit formed by a conventional forming method. An insulating layer 12, such as Borophosphosilicate glass (BPSG) or oxide, is formed on the silicon substrate 10 or metal line. A portion of the insulating layer 12 is removed by etching, for example anisotropic etching, to form a contact window 13 exposing a portion 10a of conductive material. A diffusion barrier layer 14 is formed on the periphery of the portion 10a and the contact window 13 made of a conductive material, and extends to the upper surface of the insulating layer 12. The diffusion barrier layer 14 may be, for example, a TiN _x layer that prevents diffusion and improves adhesion. Conductive material 16, such as tungsten, copper or aluminum, is filled into contact window 13 by PVD or CVD. Since the coating step is poor, an empty space 18 is formed in the conductive material 16.

In the method for forming the conductive plug of the integrated circuit described above, a diffusion barrier layer as a glue / barrier layer is deposited before the conductive material is filled into the contact window of the insulating layer. Thus, the contact window becomes narrower, and the deposition site on the diffusion barrier layer is recessed, so that an empty space is created when the conductive material is deposited. As a result, large voids severely affect the device's characteristics such as increased resistance and short circuits.

It is therefore an object of the present invention to provide a method for forming a conductive plug of an integrated circuit by subjecting the diffusion barrier layer to plasma treatment before the conductive layer is deposited. By the above method, since the conductive material is filled later, the problem of the empty space can be prevented.

1 is a cross-sectional view of a conductive plug of an integrated circuit formed by a conventional method,

2 is a cross-sectional view of a conductive plug of an integrated circuit formed by the method according to the invention.

According to a preferred embodiment of the present invention, an insulating layer is formed on a semiconductor substrate or a metal wire, and the insulating layer is etched to form a contact window exposing a conductive region of the device. A diffusion barrier layer is formed around the exposed conductive region and the contact window. Hydrogen plasma treatment is performed in the reaction chamber, and a conductive material is filled in the contact window to form a conductive plug.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of non-limiting preferred embodiments. It will be described in detail with reference to the accompanying drawings.

In FIG. 2, an insulating layer 22, such as, for example, borophosphosilicate glass or oxide, is formed on a silicon substrate or metal line semiconductor 20. Subsequently, the insulating layer 22 is etched to form a contact window 23 exposing a portion 20a of a conductive material such as, for example, a source / drain region, a gate, or a metal wire. A portion of the insulating layer 22 is removed by a method such as photolithography or anisotropic etching. A diffusion barrier layer 24 is formed on one portion 20a made of a conductive material, a circumference of the contact window 23, and an upper surface of the insulating layer 22. The diffusion barrier layer 24 may be a hybrid layer formed by physical vapor deposition or chemical vapor deposition that deposits a Ti layer followed by a TiN _x layer. Alternatively, the diffusion barrier layer 24 may be a tungsten nitride layer or a titanium-tungsten layer. Then, hydrogen plasma treatment is performed on the diffusion barrier layer 24. Hydrogen plasma treatment is carried out under the conditions of less than 3000 Watts of power, less than 3000 sccm of hydrogen introduction flow rate, less than 1000 ℃ reaction temperature, reaction time 10 seconds to 10 minutes. For example, a conductive material 26 such as tungsten, copper or aluminum is filled into the contact window 23 by PVD or CVD to form a conductive plug having a small void 28.

In this embodiment, during the hydrogen plasma treatment, the high energy particles increase the density of the diffusion barrier layer, expand the contact window, and make a number of small holes on the surface of the diffusion barrier layer to make it a rough surface. As a result, the number of deposited sites is increased, so that a smooth conductive layer can be obtained. Thus, the problem of empty space is remarkably improved. In addition, as another advantage, the x value of TiN _{x in} the diffusion barrier layer Ti / TiN _x is reduced to decrease the contact resistance.

Although the present invention has been described above as a conventional example and a preferred embodiment, it should be understood that the present invention is not limited to the above-described embodiment. Rather, the foregoing detailed description is intended to cover various modifications and similar methods included within the spirit and scope of the appended claims, the scope of which should be accorded the widest interpretation so as to encompass all other modifications and similar structures.

Claims (11)

Providing a semiconductor substrate; Forming a device having a conductive region on the semiconductor substrate; Forming an insulating layer on the semiconductor substrate; Etching the insulating layer to form a contact window exposing the conductive region of the device; Forming a diffusion barrier layer around the exposed conductive region and the contact window; Performing hydrogen plasma treatment on the diffusion barrier layer in a reaction chamber at working conditions (less than 3000 watts of power, less than 3000 sccm of hydrogen introduction flow rate, less than 1000 ° C of reaction temperature, and reaction time of 10 seconds to 10 minutes); And filling a conductive material into said contact window to form a conductive plug. The method of claim 1, wherein the conductive region is a source / drain region, and the contact window is formed to expose a portion of the source / drain region. The method of claim 1, wherein the conductive region is a metal wire, and the contact window is a via exposing a portion of the metal wire. The method of claim 1, wherein the diffusion barrier layer comprises a titanium layer and a titanium nitride layer. The method of claim 1, wherein the diffusion barrier layer comprises a tungsten nitride layer. The method of claim 1, wherein the diffusion barrier layer comprises a titanium-tungsten layer. The method of claim 1, wherein the conductive material comprises tungsten. The method of forming a conductive plug according to claim 1, wherein the conductive material comprises copper. The method of claim 1, wherein the conductive material comprises aluminum. The method of claim 1, wherein the conductive material is formed by chemical vapor deposition. The method of claim 1, wherein the conductive material is formed by physical vapor deposition.

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