KR20040052326A - Method of manufacturing capacitor for semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing a capacitor of a semiconductor device is provided to prevent bowing and bridge between storage node electrodes by using a stacked double cylindrical capacitor. CONSTITUTION: The first capacitor oxide layer(16) is formed on a substrate(10) with a plug(15). The first trench is formed by selectively etching the first capacitor oxide layer. The first storage node electrode(18) is formed on the first trench. An oxide layer is filled between the first storage node electrodes. The second capacitor oxide layer(20) is formed on the resultant structure. The second trench is formed to expose the first storage node electrode. The second storage node electrode(23) is formed on the second trench. After the second and first capacitor oxide layer are removed, a dielectric film(24) and a plate electrode(25) are sequentially formed on the exposed first and second storage node electrode.

Description

METHODS OF MANUFACTURING CAPACITOR FOR SEMICONDUCTOR DEVICE

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a capacitor of a semiconductor device, and more particularly, to a method of manufacturing a capacitor of a semiconductor device capable of securing a sufficient capacitor capacity corresponding to high integration.

In general, a capacitor used in a memory cell is composed of a storage node electrode, a dielectric film, and a plate electrode, and has a sufficient capacitor capacity corresponding to the device within a cell area which decreases with high integration. Increasingly, the height of the capacitor is increasing.

Such capacitors typically define a capacitor region by applying a capacitor oxide layer, which is a sacrificial layer, after the formation of the storage node contact, and then sequentially form the storage node electrode, the dielectric layer, and the plate electrode. Therefore, in order to obtain a capacitor having a desired height, A capacitor oxide film should be formed and etched to a corresponding thickness.

On the other hand, due to the reduction in design rule margin due to cell area reduction, it is possible to secure sufficient capacitor capacity corresponding to the device only by increasing the capacitor height, for example, 2 μm or more. Accordingly, the capacitor oxide film should be applied to a thickness of 2 μm or more and etched to 2 μm or more to form a capacitor hole to limit the capacitor region. However, when the capacitor oxide film is etched to a thickness of 2 μm or more, the holes as the etching portions become larger and the space between the holes becomes smaller, so that bowing occurs at about 5000 m from the top of the capacitor oxide film during etching, thereby causing storage nodes. Since the yield of the device is lowered by inducing an inter-electrode bridge, there is a limit to increasing the capacitor height.

The present invention has been proposed in order to solve the problems of the prior art as described above, which reduces the etching thickness of the capacitor oxide film to prevent bowing and bridge, and at the same time ensures a sufficient capacitor capacity corresponding to the highly integrated device. It is an object of the present invention to provide a method for manufacturing a capacitor of a device.

1A to 1E are perspective views illustrating a capacitor manufacturing method of a semiconductor device according to an embodiment of the present invention.

2A to 2E are cross-sectional views illustrating a method of manufacturing a capacitor of a semiconductor device in accordance with an embodiment of the present invention, and are cross-sectional views taken along the line AA ′ of FIGS. 1A to 1E.

3 is a cross-sectional view showing a capacitor of a semiconductor device according to an embodiment of the present invention.

※ Explanation of symbols for main parts of drawing

10 semiconductor substrate 11 bit line

12: first hard mask 13: bit line spacer

14 interlayer insulating film 15 plug

16, 20: first and second capacitor oxide film

17, 22: first and second trench

18, 23: first and second storage node electrodes

19: oxide film 21: second hard mask

24 dielectric film 25 plate electrode

According to an aspect of the present invention for achieving the above technical problem, an object of the present invention is the step of forming a first capacitor oxide film on a semiconductor substrate is completed a predetermined process; Etching the first capacitor oxide layer to expose a portion of the substrate to form a first trench for the capacitor; Forming a cylindrical first storage node electrode separated in a first direction only on the first trench surface; Forming an oxide layer to fill a space between the first storage node electrodes; Forming a second capacitor oxide film on the entire surface of the substrate; Etching the second capacitor oxide layer to expose the oxide layer and the first storage node electrode to form a second trench for the capacitor; Forming a cylindrical second storage node electrode separated in a first direction only on the second trench surface; Partially etching the first and second capacitor oxide layers and the first and second storage node electrodes to separate the first and second storage node electrodes in a second direction perpendicular to the first direction; Sequentially removing the first and second capacitor oxide films and the oxide films to expose the first and second storage node electrodes; Forming a dielectric film on the inner and outer surfaces of the exposed first and second storage node electrodes; And forming a capacitor by forming a plate electrode on the dielectric layer so as to fill a space between the first and second storage node electrodes having the dielectric layer formed thereon.

Here, the first direction is the short axis direction of the capacitor and the second direction is the long axis direction of the capacitor, and the first capacitor oxide film is formed only about 1/2 of the total capacitor oxide film thickness.

Hereinafter, preferred embodiments of the present invention will be introduced in order to enable those skilled in the art to more easily carry out the present invention.

1A to 1E, 2A to 2E, and 3 are perspective and cross-sectional views illustrating a method of manufacturing a capacitor of a semiconductor device according to an embodiment of the present invention, and FIGS. 2A to 2E are FIGS. 1A to 1E. It is each sectional drawing along AA 'direction.

1A and 2A, a first hard mask 12 of a nitride film is disposed on a semiconductor substrate 10 on which a cell region is defined and predetermined processes such as transistors and bit line contacts are completed, and the bit line is disposed on the semiconductor substrate 10. The bit line 11 connected to the contact is formed. Next, the bit line spacer 13 of the nitride film is formed on the sidewalls of the first hard mask 12 and the bit line 11, and the interlayer insulating film 14 is formed on the entire surface of the substrate. Thereafter, the interlayer insulating layer 14 is etched by using a self-aligned contact process so that a part of the substrate 10 between the bit lines 11 is exposed to form a contact hole, and the interlayer is embedded in the contact hole. A polysilicon film is deposited on the insulating film 14, and the polysilicon film is etched by a chemical mechanical polishing (CMP) process or an etch-back process to form a plug 15 that contacts the substrate. Here, the plug 15 acts as a storage node contact. Next, the first capacitor oxide layer 16 is formed on the entire surface of the substrate, and the first capacitor oxide layer 16 is etched to expose the plug 15 using the first mask for the storage node electrode. The first trench 17 for the capacitor is formed in the same direction as that of the capacitor. Preferably, the first capacitor oxide film 16 is one film selected from among HDP oxide film, USG film, BPSG film, PSG film, HLD oxide film, TEOS film, and SOG film, and a part thickness of the total capacitor oxide film thickness, more preferably 1 Only a thickness of about 2 is formed.

1B and 2B, a cylindrical first storage node electrode 18 is formed on a surface of a first trench 17 and a first capacitor oxide film 16 by a first conductive film such as a polysilicon film or a metal film. A first photoresist layer (not shown) is formed on the first storage node electrode 18 as a buried material film so as to be embedded in the first trench 17 in which the first storage node electrode 18 is formed. Next, the first photoresist film and the first storage node electrode 18 are etched by the CMP process or the etch back process so that the surfaces of the first capacitor oxide film 16 are exposed to each other in the short axis direction of the capacitor, that is, AA 'direction. After the first storage node electrode 18 is separated, the first photoresist film is removed.

1C and 2C, an oxide film 19 is formed to fill a space between the first storage node electrodes 18, and a second hard mask of the second capacitor oxide film 20 and the nitride film is formed on the entire surface of the substrate. 21) are formed sequentially. Here, like the first capacitor oxide film 16, the second capacitor oxide film 20 is one film selected from among HDP oxide film, USG film, BPSG film, PSG film, HLD oxide film, TEOS film, and SOG film, and total capacitor oxide film thickness. Is formed to the remaining thickness except for the thickness of the first capacitor oxide film 16. Next, the second hard mask 21 and the second capacitor oxide film 20 are etched using the first mask for the storage node electrode to expose the first storage node electrode 18 and the oxide film 19. The second trench 22 is formed.

Referring to FIGS. 1D and 2D, a cylindrical second storage node electrode is formed on a surface of the second trench 22 and the second hard mask 21 by a second conductive film such as a polysilicon film or a metal film. A second photoresist film (not shown) as a material film to be buried on the second storage node electrode 23 so as to form a 23 and to be buried in the second trench 22 where the second storage node electrode 23 is formed; To form. Next, the second photoresist film and the second storage node electrode 23 are etched by the CMP process or the etch back process so that the surfaces of the nitride film 21 are exposed, and thus the second storage in the short axis direction, that is, AA 'direction of the capacitor. After the node electrode 23 is separated, the second photoresist film is removed. Next, the nitride film 21, the first and second capacitor oxide films 16 and 19, and the first and second storage node electrodes 18 and 23 are partially etched using the second mask for the storage node. As shown in (d) of 1d, the first and second storage node electrodes 18, 23 are separated from neighboring electrodes in the long axis direction of the capacitor, that is, the BB 'direction.

1E and 2E, an oxide layer embedded between the first storage node electrodes 18 is removed after removing the first and second capacitor oxide layers 16 and 20 of the cell region using a mask that opens the cell region. (19) is removed to expose the first and second storage node electrodes (18, 23). Next, as shown in FIG. 3, dielectric layers 24 are formed on the inner and outer surfaces of the exposed first and second storage node electrodes 18, and the first and second storage on which the dielectric layers 24 are formed. The plate electrode 25 is formed on the dielectric film 24 so as to fill the space between the node electrodes 18, thereby completing the capacitor of the stacked double cylinder structure.

According to the above embodiment, by depositing the capacitor oxide film in two times and etching each to form cylindrical first and second storage node electrodes, and then forming a dielectric film and a plate electrode to form a stacked double cylinder capacitor, It is possible to prevent the bowing phenomenon by reducing the etching depth of the capacitor oxide film, thereby preventing the bridge between the storage node electrodes, thereby improving the yield of the device. In addition, the multilayered double-cylinder capacitor can ensure a sufficient capacitor capacity corresponding to high integration, thereby improving the electrical characteristics of the device.

Meanwhile, in the above embodiment, the first storage node electrode is separated using the first photoresist film as the buried material film, the first photoresist film is removed, and the space between the first storage node electrodes is again filled with an oxide film. An oxide film may be applied as the material film for eliminating the formation and removal of the first photoresist film.

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.

According to the present invention as described above, by applying a stacked double-cylinder capacitor, it is possible to prevent the bowing and the resulting bridge by reducing the etching thickness of the capacitor oxide film, so that the yield of the device can be improved and sufficient to cope with the highly integrated device. By securing the capacitor capacity, it is possible to improve the electrical characteristics of the device.

Claims (6)

Forming a first capacitor oxide film on the semiconductor substrate on which a predetermined process is completed; Etching the first capacitor oxide layer to expose a portion of the substrate to form a first trench for a capacitor; Forming a cylindrical first storage node electrode separated in a first direction only on the first trench surface; Forming an oxide layer to fill a space between the first storage node electrodes; Forming a second capacitor oxide film on the entire surface of the substrate; Etching the second capacitor oxide layer to expose the oxide layer and the first storage node electrode to form a second trench for a capacitor; Forming a cylindrical second storage node electrode separated in the first direction only on the second trench surface; Partially etching the first and second capacitor oxide layers and the first and second storage node electrodes to separate the first and second storage node electrodes in a second direction perpendicular to the first direction; Sequentially removing the first and second capacitor oxide layers and the oxide layer to expose the first and second storage node electrodes; Forming a dielectric film on inner and outer surfaces of the exposed first and second storage node electrodes; And And forming a capacitor by forming a plate electrode on the dielectric layer so as to fill a space between the first and second storage node electrodes having the dielectric layer formed thereon. The method of claim 1, Forming the first storage node electrode Forming a first storage node electrode on the surface of the first trench and the first capacitor oxide layer; Forming a first photoresist layer on the first storage node electrode to be buried in the first trench in which the first storage node electrode is formed; Separating the first storage node electrode in the first direction by etching the second photoresist layer and the first storage node electrode so that the surfaces of the first capacitor oxide layer are exposed; And And removing the second photoresist film. The method of claim 1, Forming the second storage node electrode Forming a second storage node electrode on the surface of the second trench and the second capacitor oxide film; Forming a second photoresist layer on the second storage node electrode to be buried in the second trench in which the second storage node electrode is formed; Separating the second storage node electrode in the first direction by etching the entire surface of the second photoresist layer and the second storage node electrode to expose the surface of the second capacitor oxide film; And And removing the second photoresist film. The method of claim 2 or 3, And the first direction is a short axis direction of the capacitor and the second direction is a long axis direction of the capacitor. The method of claim 2 or 3, The front surface etching is a capacitor manufacturing method of a semiconductor device, characterized in that performed by a chemical mechanical polishing process or an etch back process. The method of claim 1, The first capacitor oxide film is a capacitor manufacturing method of a semiconductor device, characterized in that formed only about 1/2 of the total capacitor oxide film thickness.