KR20060000485A - Method for forming storage node electrode of semiconductor capacitor - Google Patents

Abstract

The present invention discloses a method of forming a storage node electrode of a semiconductor capacitor capable of preventing short between storage node electrodes. The disclosed method includes providing a semiconductor substrate having a conductive plug; Forming a first oxide film having a contact hole exposing the conductive plug on the substrate; Forming a polysilicon film for a storage node electrode on the first oxide film; Forming a second oxide film on the polysilicon film to bury the contact hole structure and planarize it; Etching the polysilicon layer and the second oxide layer until a time point at which the first oxide layer is exposed; Removing a portion of the remaining polysilicon layer to form a storage node electrode of the capacitor; Selectively etching the remaining first and second oxide layers to expose a portion of an upper surface and a sidewall of the storage node electrode; Forming a nitride film over the entire surface of the resultant product; Etching the nitride layer to a point where the first oxide layer remaining after the etching is exposed to form a nitride layer pattern covering a portion of an upper surface and a sidewall of the storage node electrode; And removing the resultant first and second oxide films.

Description

METHODS FOR FORMING STORAGE NODE ELECTRODE OF SEMICONDUCTOR CAPACITOR}

1A to 1C are cross-sectional views illustrating processes for forming a storage node electrode of a semiconductor capacitor according to the related art.

2A to 2G are cross-sectional views illustrating processes for forming a storage node electrode of a semiconductor capacitor according to an embodiment of the present invention.

Explanation of symbols on main parts of drawing

20 semiconductor substrate 21 interlayer insulating film

22: first contact hole 23: conductive plug

24: second contact hole 25: the first oxide film

26 polysilicon film 27 second oxide film

26a: remaining polysilicon film 26b: storage node electrode

28: nitride film 28a: nitride film pattern

The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of forming a storage node electrode of a semiconductor capacitor for preventing short between storage node electrodes.

As the demand for semiconductor memory devices has soared, various techniques for obtaining high capacity capacitors have been proposed. The capacitor has a structure in which a dielectric film is interposed between the storage node electrode and the plate node electrode, and the capacitance thereof is proportional to the electrode surface area and the dielectric constant of the dielectric film, and is inversely proportional to the gap between the electrodes, that is, the thickness of the dielectric film.

Therefore, in order to obtain a high capacity capacitor, it is required to use a dielectric film having a large dielectric constant, to enlarge the electrode surface area, or to reduce the distance between the electrodes. However, reducing the distance between the electrodes, that is, the thickness of the dielectric film has its limitation, and researches for forming a capacitor having a high capacity have been conducted by using a dielectric film having a high dielectric constant or increasing the electrode surface area.

Here, as an example of increasing the surface area of the electrode, a storage node electrode may be formed into a concave type and a cylinder type, and recently, the surface area is enlarged by using the outer surface of the node rather than the concave type. The trend is to prefer a cylindrical shape as much as possible.

1A to 1C are cross-sectional views illustrating processes of forming a storage node electrode of a semiconductor capacitor according to the related art.

A method of forming a storage node electrode of a conventional semiconductor capacitor will be briefly described with reference to FIGS. 1A to 1C.                         

In the conventional method of forming a storage node electrode of a semiconductor capacitor, as shown in FIG. 1A, first, an interlayer insulating film 11 is formed on a semiconductor substrate 10, and then the interlayer insulating film 11 is selectively etched. A first contact hole 12 exposing a predetermined portion of the substrate 10 is formed. Then, the first contact hole 12 is filled with a conductive film to form a conductive plug 13. Subsequently, a first oxide film 15 having a second contact hole 14 exposing the conductive plug 13 is formed on the interlayer insulating film 11 including the conductive plug 13.

Next, as shown in FIG. 1B, after forming the polysilicon layer 16 for the storage node electrode on the first oxide layer 15 including the second contact hole 14, the polysilicon layer ( The second oxide layer 17 is formed on the 16 to fill the second contact hole 14.

Subsequently, as illustrated in FIG. 1C, the cylindrical oxide storage node electrode 16a is formed by chemical mechanical polishing (CMP) of the second oxide film and the polysilicon film until the first oxide film is exposed. After the formation, the remaining first and second oxide films are removed by a dip-out process.

However, in the related art, as the dip out process for removing the remaining first and second oxide layers is performed after the storage node electrode is formed, the surface tension of the wet chemical used in the dip out process is increased. The storage node electrode is tilted. As a result, a bridge is generated between adjacent storage node electrodes, and a short circuit occurs between storage node electrodes due to the bridge generation.

Accordingly, the present invention has been made to solve the above problems, and even if a bridge is generated between the storage node electrodes, a method of forming a storage node electrode of a semiconductor capacitor that can prevent the short circuit between the storage node electrodes. The purpose is to provide.

A method of forming a storage node electrode of a semiconductor capacitor of the present invention for achieving the above object comprises the steps of: providing a semiconductor substrate having a conductive plug; Forming a first oxide film having a contact hole exposing the conductive plug on the substrate; Forming a polysilicon film for a storage node electrode on the first oxide film; Forming a second oxide film on the polysilicon film to bury the contact hole structure and planarize it; Etching the polysilicon layer and the second oxide layer until a time point at which the first oxide layer is exposed; Removing a portion of the remaining polysilicon layer to form a storage node electrode of the capacitor; Selectively etching the remaining first and second oxide layers to expose a portion of an upper surface and a sidewall of the storage node electrode; Forming a nitride film over the entire surface of the resultant product; Etching the nitride layer to a point where the first oxide layer remaining after the etching is exposed to form a nitride layer pattern covering a portion of an upper surface and a sidewall of the storage node electrode; And removing the resultant first and second oxide films.

The etching process of the polysilicon film and the second oxide film uses any one of CMP and front dry etching. In addition, the nitride film may be etched using any one of CMP and full dry etching.

(Example)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A through 2G are cross-sectional views illustrating processes of forming a storage node electrode of a semiconductor capacitor according to an exemplary embodiment of the present invention.

In the method of forming a storage node electrode of a semiconductor capacitor according to an embodiment of the present invention, as shown in FIG. 2A, first, an interlayer insulating layer 21 is formed on a semiconductor substrate 20, and then the interlayer insulating layer 21 is formed. Selectively etching to form a first contact hole 22 to expose a predetermined portion of the substrate 20. Then, the first contact hole 22 is filled with a conductive film to form a conductive plug 23. Subsequently, a first oxide layer 25 having a second contact hole 24 exposing the conductive plug 13 is formed on the interlayer insulating layer 21 including the conductive plug 23.

Next, as shown in FIG. 2B, after forming the polysilicon layer 26 for the storage node electrode on the first oxide layer 25, the second oxide layer 27 is formed on the polysilicon layer 26. To form the second contact hole 24 to fill the structure.

Next, as shown in FIG. 2C, the polysilicon layer and the second oxide layer 27 are etched until the first oxide layer 25 is exposed. In this case, reference numeral 26a, which is not described in FIG. 2C, indicates the remaining polysilicon film. The etching process of the polysilicon film and the second oxide film 27 may use any one of CMP and full dry etching.

Next, as shown in FIG. 2D, a portion of the remaining polysilicon layer is removed to form the storage node electrode 26b of the capacitor.

Subsequently, as illustrated in FIG. 2E, the remaining first and second oxide films 25 and 27 are selectively etched to expose portions of the top surface and sidewalls of the storage node electrode 26b. Thereafter, a nitride film 28 is formed on the entire surface of the resultant product.

Next, as illustrated in FIG. 2F, the nitride layer is etched until the first oxide layer 25 remaining after the etching is exposed, thereby covering a portion of the top surface and the sidewall of the storage node electrode 26b. (28a) is formed. Here, the nitride film etching process uses any one of CMP and full dry etching.

Thereafter, as shown in FIG. 2G, the resultant first and second oxide films are removed by a dip out process. At this time, as the dip-out process proceeds, the storage node electrode 26b is inclined due to the surface tension of the wet chemical used in the dip-out process, so that a bridge occurs between adjacent storage node electrodes 26b. The short between the storage node electrodes 26b is prevented by the nitride layer pattern 28a formed on the storage node electrode 26b.

As described above, the present invention forms a nitride film pattern to cover a portion of the top surface and sidewalls of the storage node electrode, so that the storage node electrode is inclined during the subsequent dip-out process, and thus, between adjacent storage node electrodes. Even if a bridge is generated, a short between the storage node electrodes can be prevented by a nitride film pattern formed on the storage node electrode.

Claims (3)

Providing a semiconductor substrate provided with a conductive plug; Forming a first oxide film having a contact hole exposing the conductive plug on the substrate; Forming a polysilicon film for a storage node electrode on the first oxide film; Forming a second oxide film on the polysilicon film to bury the contact hole structure and planarize it; Etching the polysilicon layer and the second oxide layer until a time point at which the first oxide layer is exposed; Removing a portion of the remaining polysilicon layer to form a storage node electrode of the capacitor; Selectively etching the remaining first and second oxide layers to expose a portion of an upper surface and a sidewall of the storage node electrode; Forming a nitride film over the entire surface of the resultant product; Etching the nitride layer to a point where the first oxide layer remaining after the etching is exposed to form a nitride layer pattern covering a portion of an upper surface and a sidewall of the storage node electrode; And And removing the resultant first and second oxide films. The method of claim 1, wherein the polysilicon layer and the second oxide layer are etched using CMP or full dry etching. The method of claim 1, wherein the etching process of the nitride layer uses any one of CMP and dry etching.

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