KR100546111B1 - Manufacturing Method of Semiconductor Device - Google Patents

Abstract

In the present invention, a barrier metal layer / tungsten (W) layer is formed in a damascene word line forming process, and the tungsten layer is formed of a SiMP process using an interlayer oxide layer as an etching end point. And an etch back process to form a tungsten layer on the sidewall of the word line and a tungsten layer at the center of the word line at the same height.

In the method of manufacturing a semiconductor device according to the present invention, when forming a word line using a damascene process, after tungsten metal / tungsten formation, tungsten is removed to the oxide layer by the CMP method instead of the etch back method, and the tungsten is etched by the etch back method to uniform tungsten. By forming a word line having a layer, it prevents the exposure of the tungsten layer due to damage of the sidewall during the subsequent contact formation etch back process, thereby suppressing leakage current and short circuit between wirings, thereby improving the reliability of the word line and the stability of the device. And improving yield.

Description

Method for manufacturing semiconductor device

1A to 1C are cross-sectional views illustrating a method of manufacturing a word line of a semiconductor device according to the related art.

2A through 2C are cross-sectional views illustrating a method of manufacturing a word line in a semiconductor device according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

31 semiconductor substrate 32 first nitride film sidewalls

33: interlayer oxide film 34: gate oxide film

35: barrier metal layer 36: tungsten layer

37: second nitride film 38: contact hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device in which a word line having a uniform tungsten (W) layer is formed to improve characteristics, reliability, and yield of the device.

The method of manufacturing a word line among the semiconductor devices according to the related art is by a damascene process, as shown in FIG. 1A, and may be a pad oxide film (not illustrated) by a thermal oxidation process on the semiconductor substrate 11. Grow).

After forming a polycrystalline silicon layer (not shown) and a first photoresist film (not shown) on the pad oxide film, the first photoresist film is selectively exposed and developed so that only the portion where the word line is to be formed remains.

Subsequently, the polycrystalline silicon layer is selectively etched using the selectively exposed and developed first photoresist film, and then the first photoresist film is removed.

Thereafter, the first nitride film is formed on the entire surface and etched back to form the first nitride film sidewall 12 on the pad oxide films on both sides of the selectively etched polycrystalline silicon layer.

Here, the first nitride film sidewall 12 serves as a mask during lightly doped drain (LDD) ion implantation in a subsequent process, and is formed during the process of forming a bit line contact or a lower electrode contact of a capacitor. Self-Aligned-Contact (SAC) serves as a barrier layer.

Subsequently, an interlayer oxide layer 13 is formed on the entire surface including the first nitride layer sidewall 12 and etched by an etch back or chemical mechanical polishing (CMP) method as an etching end point of the polycrystalline silicon layer.

The polycrystalline silicon layer is removed to expose the semiconductor substrate 11 at the site where the word line is to be formed.

Next, the gate oxide film 14, the barrier metal layer 15, and the tungsten layer 16 are formed on the entire surface including the exposed semiconductor substrate 11.

As shown in FIG. 1B, the tungsten layer 16 is etched by an etch back method to an etching end point of the interlayer oxide layer 13 to form a word line.

As shown in FIG. 1C, a second nitride film 17 is formed on the interlayer oxide film 13 including the etched tungsten layer 16 and the second nitride film is formed on a word line between the first nitride film sidewalls 12. It etches by the CMP method so that (17) may remain.

Then, a second photoresist film is applied to the entire surface including the remaining second nitride film 17, and the second photoresist film is selectively exposed and developed so as to be removed only at a portion where bit lines and capacitor contacts are to be formed.

Subsequently, the interlayer oxide layer 13 is etched using the selectively exposed and developed second photoresist layer to form a contact hole 18, and then the second photoresist layer is removed.

In this case, when forming the contact hole 18, the second nitride layer 17 and the first nitride layer sidewall 12 are damaged to expose the tungsten layer 16.

That is, when the tungsten layer 16 is formed, bending occurs in the center of the word line, so that the tungsten layer on the sidewall 12 of the first nitride layer is formed higher than the center of the word line, so that the second nitride layer 17 and the first nitride layer 17 are formed. The tungsten layer 16 is exposed (A) due to damage to the nitride film sidewall 12.

However, in the conventional method of manufacturing a semiconductor device, the tungsten layer on the sidewall of the word line is formed due to the bending caused during the formation of the word line by performing the etch back process after forming the barrier metal layer / tungsten layer in the damascene word line forming process. Since it is formed higher than the center of the word line, the tungsten layer is exposed by damage to the sidewall of the word line during the subsequent contact formation etch back process, so that a short circuit between the leakage current and the wiring occurs, thereby deteriorating device characteristics and reliability. there was.

The present invention has been made to solve the above problems, and after forming the barrier metal layer / tungsten layer in the damascene word line forming process, the tungsten layer is subjected to the CMP process with the interlayer oxide layer as an etching end point and then etched back to the word line. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device in which the tungsten layer at the sidewall side and the tungsten layer at the center of the word line are formed at the same height.

The semiconductor device of the present invention comprises the steps of: providing a substrate having a portion where a word line is to be defined, forming a pad insulating film and a dummy layer on the substrate, and selectively etching the dummy layer so that only the portion where the word line is to be formed is left. Forming a first insulating film sidewall on the pad insulating films on both sides of the selectively etched dummy layer, forming an interlayer insulating film on the entire surface, and etching the entire interlayer insulating film to the etching end point of the dummy layer; Removing the dummy layer and the pad insulating layer so that the substrate of the portion where the line is to be formed is exposed, forming a gate insulating layer, a barrier metal layer and a metal layer on the entire surface including the exposed substrate, and etching the metal layer to an etching end point of the interlayer insulating layer. After etching by the CMP method, the bacteria were etched back to protrude the upper portion of the interlayer insulating film. And forming a word line having a single metal layer.

When described in detail with reference to the accompanying drawings a preferred embodiment of the method for manufacturing a semiconductor device according to the present invention as follows.

2A through 2C are cross-sectional views illustrating a method of manufacturing a word line in a semiconductor device according to an embodiment of the present invention.

A method of manufacturing a metal word line among semiconductor devices according to an exemplary embodiment of the present invention is based on a multi-machine process, as shown in FIG. And a first photosensitive film (not shown).

Here, the pad oxide film is formed to a thickness of 40 to 100 Pa by a low pressure (LP) or plasma enhanced (PE) method at a temperature of 400 to 1300 ° C.

The polycrystalline silicon layer may be formed at a thickness of 500 to 3000 kPa under a temperature of 400 to 1200 ° C, and may be formed instead of the doped polycrystalline silicon layer or the amorphous silicon layer.

And selectively exposing and developing the first photoresist film so as to remain only in a portion where a word line is to be formed, and then selectively etching the polycrystalline silicon layer using the selectively exposed and developed first photoresist film as a mask, and then Remove the photoresist.

Subsequently, the first nitride film is formed on the entire surface by LP or PE at a temperature of 400 to 1300 ° C., etched back, and etched back to form a first nitride film sidewall on the pad oxide films on both sides of the selectively etched polycrystalline silicon layer. 32).

In this case, the first nitride layer sidewall 32 serves as a mask during LDD ion implantation in a subsequent process and serves as a SAC barrier layer during a bit line contact or a lower electrode contact forming process of a capacitor.

Subsequently, an interlayer oxide film 33 having a thickness of 3000 to 10000 Pa is formed on the entire surface including the first nitride film sidewall 32, and optionally heat treated at a temperature of 300 to 1000 ° C., and then etch back to the etching end point of the polycrystalline silicon layer. Or by the CMP method.

The interlayer oxide layer 33 may be formed of one of PSG and APL in BPSG, PSG, FSG, PE-TEOS, PE-SiH4, HEP USG, and H.

The polycrystalline silicon layer is removed to expose the semiconductor substrate 31 at the site where the word line is to be formed.

Subsequently, a gate oxide layer 34, a barrier metal layer 35, and a tungsten layer 36 having a thickness of 40 to 100 μm are formed on the entire surface including the exposed semiconductor substrate 31.

In this case, the gate oxide layer 34 may be formed of one of HTO, Al 2 O 3, and Ta 2 O 5.

The barrier metal layer 35 is formed to a thickness of 50 to 800 kPa by a sputtering method, a PVD or a CVD method, and then optionally heat-treated at a temperature of 400 to 800 ° C. in an N 2 atmosphere, and the Ti, TiN, TiAlN, TiSiN , TaN and WN can be formed instead of one of TiSi2.

The tungsten layer 36 may be formed to a thickness of 2000 to 5000 kPa under a temperature of 300 to 1000 ° C. by sputtering, PVD, and CVD, and may be formed instead of copper (Cu).

In addition, the tungsten layer 36 includes silica or alumina-based abrasives each or simultaneously as an etching end point of the interlayer oxide layer 33, and hydrogen peroxide having a concentration of 0.5 to 10 wt% Immediately after using the added slurry, the upper portion of the interlayer oxide layer 33 was etched by CMP using a slurry containing 0.0001 to 1wt% of HNO 3, HF, HCl, and H 2 SO 4 alone or in an appropriate combination. It is etched back to protrude to form a word line having the uniform tungsten layer 36.

As shown in FIG. 2B, after the second nitride film 37 having a thickness of 200 to 800 占 퐉 is formed on the entire surface including the word line by the LP method or the PE method, the first nitride film sidewall 32 is formed. The interlayer oxide film 33 is etched to the end of the etch back or CMP method while maintaining a general silica-based oxide film slurry having a pH of 2 to 12 with a size of 50 to 500 nm as the end point of etching so that the second nitride film 37 remains on the word line therebetween. By etching.

As shown in FIG. 2C, a second photoresist film is applied to the entire surface including the remaining second nitride film 37, and the second photoresist film is selectively exposed and developed so as to be removed only at a portion where a bit line and a capacitor contact are to be formed.

The interlayer oxide layer 33 is etched using the selectively exposed and developed second photoresist layer to form a contact hole 38, and then the second photoresist layer is removed.

In this case, when the contact hole 38 is formed, the tungsten layer 36 is damaged because the second nitride layer 37 and the first nitride layer sidewall 32 are damaged, but the word line has a uniform tungsten layer 36. This is not exposed.

In the method of manufacturing a semiconductor device according to the present invention, when forming a word line using a damascene process, after tungsten metal / tungsten formation, tungsten is removed to the oxide layer by the CMP method instead of the etch back method, and the tungsten is etched by the etch back method to uniform tungsten. By forming a word line having a layer, it prevents exposure of the tungsten layer due to damage of the side wall during the subsequent contact forming etch back process, thereby suppressing leakage current and short circuit between wirings, thereby improving word line reliability and improving device stability and yield. It is effective to improve.

Claims (8)

Providing a substrate defining a portion where a word line is to be formed; Forming a pad insulating film and a dummy layer on the substrate; Selectively etching the dummy layer so that only the portion where the word line is to be formed remains; Forming sidewalls of a first insulating layer on pad insulating layers on both sides of the selectively etched dummy layer; Forming an interlayer insulating film on the entire surface; Etching the interlayer insulating layer to an etch end point of the dummy layer; Removing the dummy layer and the pad insulating layer so that the substrate of the portion where the word line is to be formed is exposed; Forming a gate insulating film, a barrier metal layer, and a metal layer on the entire surface including the exposed substrate; And etching the metal layer by the chemical mechanical polishing method to the etching end point of the interlayer insulating layer, and then etching the entire surface to protrude the upper portion of the interlayer insulating layer to form a word line having the uniform metal layer. The manufacturing method of the semiconductor element made into. The method of claim 1, A method for manufacturing a semiconductor device, wherein the pad insulating film is formed to a thickness of 40 to 100 kPa by a LP or PE method at a temperature of 400 to 1300 ° C. The method of claim 1, The dummy layer is formed of a polycrystalline silicon layer, a doped polycrystalline silicon layer, and an amorphous silicon layer having a thickness of 500 to 3000 GPa under a temperature of 400 to 1200 ° C. The method of claim 1, The interlayer insulating film is formed of one of PSG and APL in BPSG, PSG, FSG, PE-TEOS, PE-SiH4, HEP USG, H having a thickness of 3000 to 10000Å and selectively heat-treated at a temperature of 300 to 1000 ° C. Method of manufacturing a semiconductor device. The method of claim 1, And the gate insulating film is formed of one of an oxide film having a thickness of 40 to 100 kV, HTO, Al2O3, and Ta2O5. The method of claim 1, The barrier metal layer is formed to a thickness of 50 to 800 kPa by a sputtering method, a PVD or a CVD method, and then optionally heat treated at a temperature of 400 to 800 ° C. in an N 2 atmosphere, and among Ti, TiN, TiAlN, TiSiN, TaN, and WN TiSi 2. Method for manufacturing a semiconductor device, characterized in that formed in one. The method of claim 1, The metal layer is formed of tungsten or copper having a thickness of 2000 to 5000 kPa under a temperature of 300 to 1000 ° C. by sputtering, PVD and CVD methods. The method of claim 7, wherein The tungsten layer includes silica or alumina-type up-slave, respectively or simultaneously, as an etching end point of the interlayer insulating layer, and immediately after using a slurry containing 0.5-10 wt% hydrogen peroxide, HNO 3, HF, Method for manufacturing a semiconductor device, characterized in that the etching by the CMP method using a slurry containing HCl, H2SO4 alone or in a suitable combination.

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