KR100558034B1 - Method for forming semiconductor device capable of preventing plug loss during tungsten bit line formation process - Google Patents

Abstract

The present invention provides a tungsten bit line and a titanium nitride plug which can prevent the plug connecting the bit line and the lower conductive layer from being damaged during the etching process for forming the bit line in the semiconductor device manufacturing method including the tungsten bit line. The present invention relates to a method of manufacturing a semiconductor device having a semiconductor device, the method comprising: forming a plug for connecting a lower conductive layer and a bit line with TiN that is not etched in an etching process using a WF ₆ gas, and forming a bit line with tungsten.

Tungsten, Bitline, TiN, Plug, WF6, Etch

Description

Method of manufacturing semiconductor device that can prevent plug damage when forming tungsten bit line             

1 and 2 is a process chart showing a method for forming a bit line of a semiconductor device according to the prior art,

3A and 3B illustrate a process of forming a bit line of a semiconductor device in accordance with an embodiment of the present invention.

* Description of reference numerals for the main parts of the drawings *

30: lower conductive layer 31: interlayer insulating film

32: TiN 33: tungsten film

C: contact hole

TECHNICAL FIELD The present invention relates to the field of semiconductor memory device manufacturing, and more particularly, to a method of forming a bit line of a semiconductor device.

Tungsten silicide is deposited to form bit lines in ultra-high density semiconductor devices. Tungsten silicide layer not only has a very high resistivity of the thin film but also has a very poor thermal stability with the silicon oxide layer at a high temperature. Therefore, in order to form a bit line, a polysilicon film is first deposited by chemical vapor deposition and then tungsten silicide is deposited on the polysilicon film.

However, due to the high integration of semiconductor devices, the line width of the bit line is reduced and the line resistance is greatly increased, thereby degrading the characteristics such as delaying the signal processing speed of the device.

In order to improve this problem, studies have been conducted to form a bit line with a metal tungsten film having a metal resistance of about 1/10 of the tungsten silicide layer. As such, when tungsten is used as the metal wiring, the plug for the bit line contact is formed of polysilicon or tungsten.

1 (A) and (B) are cross-sectional views and a plan view showing a state in which the plug 12 and the bit line 13 wiring are completed, and reference numeral 10 denotes a lower conductive layer, 11 'represents an interlayer insulating film, and' C 'represents a contact hole, respectively.

As shown in FIG. 1, when the wiring width of the bit line 13 is relatively wider than that of the contact hole, the bit line 13 covers the contact hole sufficiently to disconnect the plug 12 and the bit line 13. This does not happen.

However, as the high integration of the device is accelerated, the bit line wiring width and the contact hole size are reduced. As a result, the contact holes C and the bit lines 13 are shown in FIGS. 2A and 2B. Misalignment may occur between them.

When misalignment occurs as described above, the plug 12 inside the contact hole C is exposed, and the plug 12 made of tungsten or polysilicon is formed by the etching agent WF ₆ during the tungsten film etching process for forming the bit line 13. There is a problem that the void (V) is generated in the contact hole by etching.

In other words, the polysilicon or tungsten plugs embedded in the bit line contact holes C are etched, which causes breakage of electrical flow and adversely affects device characteristics.

The present invention has been made to solve the above problems in the semiconductor device manufacturing method having a tungsten bit line to prevent damage to the plug connecting the bit line and the lower conductive layer during the etching process for forming the bit line. It is an object of the present invention to provide a method for manufacturing a semiconductor device having a tungsten bit line and a titanium nitride plug.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, the method comprising: forming a contact hole exposing the conductive layer by selectively etching an interlayer insulating layer formed on the conductive layer; Forming a TiN plug in the contact hole; Depositing a tungsten film on the entire structure in which the TiN plug is formed; And selectively etching the tungsten film by etching using WF ₆ gas to form a tungsten bit line.

The present invention is characterized by forming a plug for connecting the lower conductive layer and the bit line with TiN that is not etched in the etching process using WF ₆ gas, and forming the bit line with tungsten.

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

First, as shown in FIG. 3A, the interlayer insulating layer 31 formed on the lower conductive layer 30 is selectively etched to form a contact hole C exposing the lower conductive layer 30. A metal TiN film 32 is deposited.

Since the contact hole has a diameter of 0.2 μm or less, a TiN film having good buried characteristics cannot be formed by a conventional physical vapor deposition method. Thus, the TiN film 32 is formed by chemical vapor deposition under the following conditions. do. That is, as the deposition source, 5 sccm to 20 sccm of TiCl ₄ , which is an organic source, is injected, and RF power of 100 W to 1 mW is applied at 300 ° C. to 800 ° C. and 0.5 torr to 100 torr pressure. . In this case, a plasma enhanced chemical vapor deposition method may be used.

The TiN film 32 formed as described above is planarized by chemical mechanical polishing or etch back to form the TiN film 32 plug inside the contact hole C. FIG.

Next, a metal tungsten film 33 is deposited on the interlayer insulating film 31 and the TiN film 32 plug.

Subsequently, a mask process for patterning the tungsten film 33 and an etching process using WF ₆ are performed to form a tungsten film 33 bit line as shown in FIGS. 3B and 3B. The TiN film 32 is not etched by WF ₆ even when the TiN film 32 inside the contact hole is exposed due to the misalignment that occurs during the mask process, so that the plug is not damaged.

The present invention made as described above can be used not only for the bit line wiring forming process but also for the metal wiring forming process.

Meanwhile, in the embodiment of the present invention, the case in which the TiN film 32 is embedded in the entire contact hole has been described, but a part of the plug may be formed of tungsten or polysilicon, and the TiN film may be formed on the plug.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention made as described above can effectively prevent damage to the plug in the etching process for forming the bit line can increase the process margin and can prevent the deterioration of the characteristics of the device.

Claims (5)

delete delete In the semiconductor device manufacturing method, Selectively etching the interlayer insulating film formed on the conductive layer to form a contact hole exposing the conductive layer; Forming a TiN plug in the contact hole; Depositing a tungsten film on the entire structure in which the TiN plug is formed; And Selectively etching the tungsten film by etching using WF ₆ gas to form a tungsten bit line Semiconductor device manufacturing method comprising a. The method of claim 3, wherein Forming the TiN plug, Forming a TiN film by chemical vapor deposition using TiCl ₄ ; And And exposing the interlayer dielectric layer by chemical mechanical polishing or full surface etching of the TiN layer. The method of claim 4, wherein In the step of forming the TiN film, 5 sccm to 20 sccm of TiCl ₄ is injected, A method of manufacturing a semiconductor device, characterized by applying RF power of 100 W to 1 kW at a temperature of 300 to 800 ° C. and a pressure of 0.5 torr to 100 torr.

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