KR100230735B1 - Process for fabricating semiconductor device - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a semiconductor device capable of reducing contact resistance by forming a contact plug having a conductive spacer in a contact hole to prevent loss of the contact plug, and forming an insulating film on the semiconductor substrate. ; Etching the insulating film to a predetermined depth to form a trench in the insulating film; Forming first conductive film spacers on both sidewalls of the trench; Etching the insulating film to expose the substrate under the trench using the first conductive film spacer as an etching mask to form a contact hole, and exposing the spacer over the insulating film; Forming a second conductive film on the entire surface of the substrate to be filled in the contact hole; And etching the second conductive film to expose the insulating film to form a contact plug.

Description

Manufacturing method of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for forming a contact plug of a semiconductor device capable of preventing loss of a contact plug using a spacer.

As the semiconductor device becomes finer and more highly integrated, the area of the contact hole for contacting the gate electrode or the source and drain diffusion regions of the polysilicon film with the metal wiring becomes very small, and the depth of the PN junction of the diffusion regions becomes thinner, An increase in contact resistance of wirings and breakage of PN junctions due to wiring formation has emerged as a serious problem. In addition, since the reduction of the length in the lateral direction is mainly the miniaturization of the current device, the aspect ratio of the surface step due to the high integration increases. Therefore, the coating power of the metal wiring film formed by the general sputtering method is weakened, so that the wiring is short-circuited, which causes a problem of greatly lowering the reliability of the device.

On the other hand, in order to solve the increase in resistance in the conventional wiring, in order to increase the operation speed of the semiconductor device, a conductive material is embedded in the contact hole to act as a contact plug, thereby preventing wiring defects caused by an increase in the aspect ratio during metal wiring. Could not go away.

1 is a cross-sectional view illustrating a metal wiring structure of a semiconductor device using the above-described conventional contact plug. As shown in FIG. 1, the first conductive film 3 embedded in the contact hole of the insulating film 2 is formed. The contact hole is contacted with the substrate 1 through the contact hole, and the first conductive layer 3 and the second conductive layer pattern 4 are contacted to form a metal wiring.

FIG. 2 is a cross-sectional view illustrating a metal wiring structure in which the contact plug is applied to a stacked via contact. As illustrated in FIG. 2, a first conductive layer is formed through a contact hole provided in the first insulating layer 12. The films 13 are in contact with the substrate 11, respectively. At this time, the predetermined first conductive layer 13 of the first conductive layer pattern is patterned by the first metal layer wiring, and the predetermined first conductive layer 13 acts as a contact plug so that the upper second conductive layer 15 is formed. And via vias provided in the second insulating layer 14 to form a stack via contact.

However, the following problem occurred in the metal wiring using the conventional contact plug mentioned above.

That is, as shown in FIG. 1, the first conductive layer is patterned so as to remain only in the contact hole to form the contact plug, and when the first conductive layer is etched according to the patterning, the first conductive layer on the contact hole is partially lost. In contact with the second conductive film, a contact failure occurs.

In addition, as shown in FIG. 2, the first conductive film is simultaneously patterned to form the first conductive film as the first metal wiring layer and the plug, respectively. The etching of the first conductive film according to the patterning is performed between the first metal wiring layer. Since excessive etching is performed to prevent the bridge, the first conductive film formed by the contact plug is partially lost after the etching, thereby causing a stack via contact failure.

As a result, the contact resistance is increased to lower the reliability of the device.

Accordingly, the present invention has been made in view of the above-described problems, and includes a conductive film spacer in a contact hole to form a contact plug to prevent loss of the contact plug, thereby reducing the contact resistance of the semiconductor device manufacturing method. The purpose is to provide.

1 and 2 are cross-sectional views showing a metal wiring structure according to the conventional contact plug formation.

3A to 3E are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

31 semiconductor substrate 32 insulating film

33 trench 34 first polysilicon film spacer

35 contact hole 36 second polysilicon film

Method for manufacturing a semiconductor device according to the present invention for achieving the above object comprises the steps of forming an insulating film on a semiconductor substrate; Etching the insulating film to a predetermined depth to form a trench in the insulating film; Forming first conductive layer spacers on both sidewalls of the trench; Etching the insulating layer to expose the substrate under the trench using the first conductive layer spacer as an etching mask to form a contact hole, and exposing the spacer over the insulating layer; Forming a second conductive film on the entire surface of the substrate to be buried in the contact hole; And etching the second conductive layer to expose the insulating layer to form a contact plug.

The first and second conductive layers may be polysilicon layers, and the forming of the first conductive layer spacer may include depositing a first conductive layer on the trench bottom and both sidewalls and the insulating layer. step ; And blanket etching the first conductive layer.

According to the present invention having the above configuration, after forming the first conductive film spacer so as to be exposed on the insulating film on which the contact hole is formed, the contact plug according to the etching by depositing a second conductive film identical to the first conductive film to be sufficiently embedded in the contact hole Can prevent the loss.

EXAMPLE

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

3A to 3E are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

First, as shown in FIG. 3A, an insulating film 32 is formed on the semiconductor substrate 31, a mask pattern (not shown) is formed on the insulating film 32 with photolithography, and then the mask pattern is formed. The insulating film 32 is wet or dry etched to a predetermined depth to form the trench 33 in the insulating film 32, and the mask pattern is removed by a known method.

As shown in FIG. 3B, a first polysilicon film is deposited as a conductive material on the bottom and both sidewalls of the trench 33 and the insulating film 32, and the first polysilicon film is blanket-etched to form both sidewalls of the trench 33. The first polysilicon film spacer 34 is formed.

As shown in FIG. 3C, the insulating layer 32 is blanket-etched to form the contact hole 35 to expose the substrate 31 under the trench 33 using the spacer 34 as an etch mask, and the spacer ( 34 is exposed over the insulating film 32.

As shown in FIG. 3D, a second polysilicon film 36 is deposited on the structure of FIG. 3C with the same material as the conductive material so as to be sufficiently filled in the contact hole 35. As shown in FIG. At this time, the contact hole 35 is deposited relatively thick by the spacer 34.

As shown in FIG. 3E, the second polysilicon layer 36 is blanket-etched until the insulating layer 32 is exposed, so that a conductive material is formed in the contact hole by the height of the spacer 34 exposed on the insulating layer 32. Completely formed contact plugs are completed.

Thereafter, although not shown, a metal wiring contacting the contact plug is formed.

According to the above embodiment, the same conductive material is sufficiently embedded in the contact hole by the spacer of the conductive material formed to be exposed to a predetermined portion higher than the depth of the contact hole, and is thickly deposited on the contact hole. Loss can be prevented.

Therefore, the reliability of the device can be improved by reducing the contact resistance of the device by preventing contact failure with the upper wiring caused by the loss of the contact plug.

Claims (7)

Forming an insulating film on the semiconductor substrate; Etching the insulating film to a predetermined depth to form a trench in the insulating film; Forming first conductive layer spacers on both sidewalls of the trench; Etching the insulating layer to expose the substrate under the trench using the first conductive layer spacer as an etching mask to form a contact hole, and exposing the spacer over the insulating layer; Forming a second conductive film on the entire surface of the substrate to be buried in the contact hole; And etching the second conductive film to expose the insulating film to form a contact plug. The method of manufacturing a semiconductor device according to claim 1, wherein the first and second conductive films are the same film. The method of claim 2, wherein the first and second conductive films are polysilicon films. The method of claim 1, wherein the forming of the trench is performed by wet etching. The method of claim 1, wherein the forming of the trench is performed by dry etching. The method of claim 1, wherein the forming of the first conductive film spacer comprises: depositing a first conductive film on the trench bottom and both sidewalls and the insulating film; And blanket etching the first conductive layer. The method of claim 1, wherein the insulating layer is blanket etched in the forming of the contact hole.