KR20010059013A - A method for forming a capacitor of a semiconductor device - Google Patents

Abstract

PURPOSE: A method for forming a capacitor is to improve an insulating characteristic between cylindrical storage electrodes by bending an upper portion of an insulating film toward a region on which a storage electrode is formed. CONSTITUTION: The first insulating film(13) is formed on a lower insulating layer(11) of a substrate. The first insulating film and the lower insulating layer are etched to form a storage electrode contact plug(15). The second insulating film pattern is formed on the contact plug. The third insulating film spacer is formed on a sidewall of the second insulating film pattern, and the fourth insulating film is formed on the entire surface. The fourth insulating film(21) is etched to expose the second insulating film pattern. The second and fourth insulating films are removed, with the fourth insulating film deposited on the third insulating spacer being remaining. A conductive layer for a storage electrode connected to the contact plug is formed on the entire surface, and then the fifth insulating film is formed on the conductive layer.

Description

A method for forming a capacitor of a semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a capacitor of a semiconductor device, and more particularly, to a technique for solving a problem that it is difficult to secure a minimum distance between capacitors due to a limitation of a lithography process due to high integration of a semiconductor device.

As semiconductor devices are highly integrated and cell size is reduced, it is difficult to secure a capacitance that is proportional to the surface area of the storage electrode.

In particular, in a DRAM device having a unit cell composed of one MOS transistor and a capacitor, it is important to reduce the area while increasing the capacitance of a capacitor that occupies a large area on a chip, which is an important factor for high integration of the DRAM device.

Thus, εo × εr × A) / T (where, εo is the vacuum dielectric constant, εr is the dielectric constant of the dielectric film, A is the area of the capacitor and T is the thickness of the dielectric film) of the capacitor C In order to increase, a method of using a material having a high dielectric constant as a dielectric film, forming a thin dielectric film, or increasing the surface area of a storage electrode has been used.

In addition, a storage electrode having a three-dimensional structure was formed to increase the surface area of the storage electrode.

The most commonly used shape is a cylindrical storage electrode.

Although not shown, a method of forming a capacitor of a semiconductor device according to the prior art will be described.

First, a lower insulating layer is formed on the semiconductor substrate. In this case, the lower insulating layer is formed of unit devices such as an isolation layer, a word line, and a bit line.

The lower insulating layer is made of B.S.G. (Brophospho silicate glass, hereinafter referred to as BSPG) It is formed of an insulating material with excellent fluidity such as an insulating film.

A first conductor connected to the impurity junction region of the semiconductor substrate is formed on the entire surface, and a sacrificial oxide film is formed thereon.

The sacrificial oxide film and the first conductor are patterned using a storage electrode mask.

Next, spacers are formed on the etch sidewalls of the sacrificial oxide layer and the first conductor. The cylindrical storage electrode is formed by removing the sacrificial oxide film.

As described above, the method of forming a capacitor of a semiconductor device according to the related art is formed by forming a cylinder-type storage electrode in a process of patterning a sacrificial oxide film on a region where a capacitor is formed and forming a spacer on the sidewalls, resulting in high integration of the semiconductor device. Since it is difficult to expose the minimum distance between the spacers, a short may be generated between the spacers on the sidewalls of the cylindrical storage electrodes, thereby degrading characteristics and reliability of the semiconductor device.

In order to solve the above problems of the prior art, the insulating film is patterned on a portion where the storage electrode is not formed, and the upper side is bent to a region where the storage electrode is formed. It is an object of the present invention to provide a method for forming a capacitor of a semiconductor device which improves the characteristics and reliability of the semiconductor device by improving the insulating properties, and in particular, forming a larger gap than the other part of the upper side of the cylinder sidewall having the weakest characteristic.

1A to 1G are cross-sectional views illustrating a method of forming a capacitor of a semiconductor device in accordance with an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

11: lower insulating layer 13: first insulating film

15: storage electrode contact plug 17: second insulating film

19: third insulating film 21: fourth insulating film

23 conductive layer for storage electrode 25 fifth insulating film

Capacitor forming method of a semiconductor device according to the present invention for achieving the above object,

Forming a first insulating film on the lower insulating layer on the semiconductor substrate;

Forming a storage electrode contact plug by etching the first insulating layer and the lower insulating layer;

Forming a second insulating film pattern on the contact plug by a photolithography process using a storage electrode mask thereon;

Forming a third insulating film spacer on the sidewalls of the second insulating film pattern and forming a fourth insulating film on an entire surface thereof;

Etching the fourth insulating layer by a planarization etching process to expose the second insulating layer pattern;

Removing the second and fourth insulating films while leaving a fourth insulating film between the third insulating film spacers;

Forming a fifth insulating film for forming a conductive layer for a storage electrode connected to the contact plug on the entire surface and planarizing an upper portion thereof;

And flattening etching until the fourth insulating layer is exposed and removing the fifth insulating layer to form a cylindrical storage electrode having an upper end portion of the cylindrical sidewall bent into the cylinder.

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

1A to 1G are cross-sectional views illustrating a method of forming a capacitor of a semiconductor device in accordance with an embodiment of the present invention.

First, a lower insulating layer 11 is formed on a semiconductor substrate (not shown). In this case, the lower insulating layer 11 is formed of unit devices such as an isolation layer, a word line and a bit line.

The lower insulating layer 11 is made of B.S.G. (Brophospho silicate glass, hereinafter referred to as BSPG) It is formed of an insulating material with excellent fluidity such as an insulating film.

Next, a first thickness of the first insulating layer 13 is formed on the lower insulating layer 11, and the first insulating layer 13 and the lower insulating layer 11 are formed by an etching process using a storage electrode contact mask (not shown). Etching to form a contact hole for exposing a predetermined region of the semiconductor substrate.

In addition, a contact plug 15 filling the contact hole is formed. In this case, the contact plug 15 is formed of a conductive layer such as tungsten or polysilicon. (FIG. 1A)

Next, a second insulating film 17 is formed over the entire surface, and as thick as the height of the cylindrical storage electrode to be formed in a subsequent process.

Then, patterning is performed by a photolithography process using a storage electrode mask (not shown) (FIG. 1B).

Next, spacers are formed on the sidewalls of the second insulating layer 17 as the third insulating layer 19. (FIG. 1C)

A fourth insulating film 21 is formed over the entire surface and planarized etching is performed until the first insulating film 17 is exposed.

In this case, the planarization etching process may be performed by chemical mechanical polishing (hereinafter referred to as CMP) method or by a full surface etching process. (FIG. 1D, FIG. 1E)

Next, the second insulating layer 17 and the third insulating layer 19 are removed and the fourth insulating layer 21 is left between the spacers of the third insulating layer 19, and at the same time, the contact plug 15 of the storage electrode 15 is removed. Expose

Then, the conductive electrode 13 for the storage electrode, which is connected to the semiconductor substrate through the contact plug 15, is formed to have a predetermined thickness on the entire surface.

Next, a fifth insulating film 25 is formed to planarize the entire upper surface portion. In this case, the fifth insulating film 25 may use a photosensitive film instead. (FIG. 1F)

In addition, the planar etching is performed by the CMP method so that the fourth insulating layer 21 is exposed, and the upper sidewall of the cylindrical storage electrode is formed to be inclined to the inner side of the cylindrical shape, thereby improving insulation characteristics.

In this case, the CMP method may be replaced by a full dry etching process. (Fig. 1g)

As described above, in the method of forming the capacitor of the semiconductor device according to the present invention, an insulating pattern is formed between the cylindrical storage electrode regions and the sidewall spacers of the cylindrical storage electrode are formed using the same, thereby easily improving the insulation characteristics between the storage electrodes. It is possible to improve the characteristics and reliability of the semiconductor device, thereby providing an effect that can improve the productivity and yield of the semiconductor device.

Claims (3)

Forming a first insulating film on the lower insulating layer on the semiconductor substrate; Forming a storage electrode contact plug by etching the first insulating layer and the lower insulating layer; Forming a second insulating film pattern on the contact plug by a photolithography process using a storage electrode mask thereon; Forming a third insulating film spacer on the sidewalls of the second insulating film pattern and forming a fourth insulating film on an entire surface thereof; Etching the fourth insulating layer by a planarization etching process to expose the second insulating layer pattern; Removing the second and fourth insulating films while leaving a fourth insulating film between the third insulating film spacers; Forming a fifth insulating film for forming a conductive layer for a storage electrode connected to the contact plug on the entire surface and planarizing an upper portion thereof; Forming a cylindrical storage electrode having a flattened etch until the fourth insulating layer is exposed and removing the fifth insulating layer to form an upper end portion of the cylindrical sidewall bent into the cylinder. The method of claim 1, The planarization etching process is a capacitor forming method of a semiconductor device, characterized in that performed by a CMP process or a full dry etching process. The method of claim 1, And the fifth insulating film is formed of a photosensitive film instead.