KR20010004960A - A method for forming storage node in semiconductor device using selective hemi-spherical silicon grain - Google Patents

Abstract

PURPOSE: A method for forming a charge storage electrode using HSG(hemispherical silicon grain) layer is provided to prevent an electric short between charge storage electrodes, and enhance an electric characteristic and a production yield of a semiconductor device, by suppressing an HSG growth on an upper part of a cylinder structure of a charge storage electrode. CONSTITUTION: A contact hole for exposing a semiconductor substrate after penetrating a predetermined interfacial insulating layer(21) is formed. A contact plug(22) is buried in the contact hole. The first sacrificial layer is formed on the total structure. The first sacrificial layer of a charge storage electrode forming area is selectively etched. Amorphous silicon layer(24) is formed along the total structure surface. The second sacrificial layer is formed on the amorphous silicon layer. The second sacrificial layer is recessed to expose the amorphous silicon layer. A plasma processing is performed about the exposed amorphous silicon layer by using a gas having a carbon. The first and second sacrificial layers are removed. A selective hemispherical silicon grain is formed on the exposed amorphous silicon layer.

Description

A method for forming storage node in semiconductor device using selective hemi-spherical silicon grain}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor manufacturing technology, and more particularly, to a method of forming a charge storage electrode using hemi-spherical silicon grain (HSG) in semiconductor device manufacturing.

In general, although the area of a unit cell decreases as the degree of integration of semiconductor devices including DRAM increases, there is a problem of maintaining a predetermined amount or more of capacitance in order to secure operating characteristics of the semiconductor device.

In order to solve these problems, various three-dimensional charge storage electrodes have been proposed to secure the surface area of the charge storage electrodes, but the difficulty of forming the charge storage electrodes is high, and after the completion of the process, a large step is caused to cause a subsequent process. There was a problem that made it difficult.

In addition, as another solution, a high dielectric material such as Ta ₂ O ₅ , (Ba _1-x Sr _x ) TiO ₃ (BST) was used to secure the capacitance, but it is still inadequate in the process to be applied to the actual device. There was a problem with mass production.

Recently, a technique of applying a hemispherical silicon grain thin film to a charge storage electrode has been proposed. This technology can increase the surface area of the thin film by roughening the surface of the thin film by using the microstructure characteristics, which can be applied to the high-density semiconductor device of 256M DRAM or higher. In particular, the selective HSG process in which the HSG is grown only in the charge storage electrode forming region is in the spotlight.

1A to 1D illustrate a process of forming a selective HSG charge storage electrode of a cylinder structure according to the prior art, which will be described below with reference to the drawing.

First, as shown in FIG. 1A, a planarized interlayer insulating film 11 is formed and a contact hole is formed on a silicon substrate 10 that has undergone a conventional transistor (not shown) forming process. Then, the contact plug 12 is formed. To form. Subsequently, the first sacrificial oxide film 13 is formed on the entire structure, the first sacrificial oxide film 13 in the region where the charge storage electrode is to be formed is selectively removed, and then the amorphous silicon film 14 is removed along the entire structure surface. The second sacrificial oxide film 15 is deposited on the entire structure.

Next, as illustrated in FIG. 1B, plasma etching using a CF-based gas is performed to etch back the second sacrificial oxide layer 15, and an amorphous phase on the first sacrificial oxide layer 13 is formed by plasma etching using Cl-based gas. The silicon film 14 is removed.

Subsequently, as shown in FIG. 1C, the first sacrificial oxide film 13 and the second sacrificial oxide film 15 are wet removed to form a charge storage electrode pattern, and the HSG 16 is exposed to the exposed amorphous silicon film 14. Is deposited and grown.

Subsequently, wet cleaning is performed as shown in FIG. 1D, and a dielectric film (not shown) and plate electrode forming process are performed.

At this time, when wet cleaning, the HSG 16 in the upper portion A of the cylinder structure of the amorphous silicon film 14 is separated and positioned between the charge storage electrodes B, thereby causing a bridge between the charge storage electrodes. And, there was a problem that acts as a particle (particle) in the subsequent process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a charge storage electrode of a semiconductor device capable of preventing an increase in bridges and particles between charge storage electrodes due to HSG separated from an upper portion of a cylinder structure.

1A to 1D are process diagrams for forming a selective HSG charge storage electrode of a cylinder structure according to the prior art.

2A to 2C are diagrams illustrating a process of forming a selective HSG charge storage electrode of a cylinder structure according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

20 silicon substrate 21 interlayer insulating film

22 contact plug 23 first PSG film

24 amorphous silicon film 25 second PSG film

26: HSG C: upper part of the cylinder structure

According to another aspect of the present invention, there is provided a method of forming a charge storage electrode of a semiconductor device, the method including: forming a contact hole through a predetermined interlayer insulating film to expose the semiconductor substrate; A second step of embedding a contact plug in the contact hole; A third step of forming a first sacrificial layer on the entire structure after the second step; A fourth step of selectively etching the first sacrificial layer in the region where the charge storage electrode is to be formed; A fifth step of forming an amorphous silicon film along the entire structure surface of the fourth step; A sixth step of forming a second sacrificial film on the amorphous silicon film; Recessing the second sacrificial layer to expose the amorphous silicon layer; An eighth step of recessing the exposed amorphous silicon film to expose the first sacrificial film; A ninth step of performing a plasma treatment using a gas containing carbon on the exposed amorphous silicon film; A tenth step of removing the first and second sacrificial layers; And an eleventh step of forming a selective hemispherical silicon grain on the exposed surface of the amorphous silicon film.

In addition, the present invention is a first step of forming a contact hole through the predetermined interlayer insulating film to expose the semiconductor substrate; A second step of embedding a contact plug in the contact hole; A third step of forming a first sacrificial layer on the entire structure after the second step; A fourth step of selectively etching the first sacrificial layer in the region where the charge storage electrode is to be formed; A fifth step of forming an amorphous silicon film along the entire structure surface of the fourth step; A sixth step of forming a second sacrificial film on the amorphous silicon film; Recessing the second sacrificial layer to expose the amorphous silicon layer; An eighth step of etching back the exposed amorphous silicon film using a gas containing carbon to expose the first sacrificial film; A ninth step of removing the first and second sacrificial layers; And a tenth step of forming a selective hemispherical silicon grain on the exposed surface of the amorphous silicon film.

That is, the present invention is a technique of using a gas containing carbon (for example, CF-based gas) when etching the amorphous silicon film to form a charge storage electrode pattern (e.g. during etchback or post-etchback plasma treatment), the charge storage electrode The HSG is not formed on the upper part of the cylinder structure so that there is no fear of the HSG falling off in the subsequent process.

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.

2A to 2C illustrate a process of forming a selective HSG charge storage electrode having a cylinder structure according to an embodiment of the present invention, which will be described below with reference to the drawings.

First, as shown in FIG. 2A, a planarized interlayer insulating film 21 is formed and a contact hole is formed on the silicon substrate 20 after the normal transistor (not shown) forming process is completed. Then, the contact plug 22 is formed. To form. Subsequently, a first PSG (phosphosilicate glass) film 23 as a sacrificial film is formed on the entire structure, and the first PSG film 23 in the region where the charge storage electrode is to be formed is selectively removed. An amorphous silicon film 24 is deposited, and a second PSG film 25 is deposited over the entire structure.

Next, as shown in FIG. 2B, plasma etching using a CF-based gas is performed to etch back the second PSG film 25, and an amorphous phase on the first PSG film 23 through plasma etching using a Cl-based gas. The silicon film 24 is removed.

Subsequently, after performing CF plasma treatment on the entire structure surface, as shown in FIG. 2C, the first PSG film 23 and the second PSG film 25 are wet-removed to form a charge storage electrode pattern, and exposed. The HSG 26 is deposited and grown on the amorphous silicon film 24. At this time, the HSG 26 is not grown in the upper portion C of the cylinder structure of the amorphous silicon film 24.

Thereafter, a normal cleaning process is performed, and a process of forming a dielectric film (not shown) and a plate electrode (not shown) are performed to complete capacitor manufacturing.

FIG. 3 illustrates a scanning electron microscope (SEM) photograph of a hemispherical silicon grain charge storage electrode having a cylindrical structure formed according to an embodiment of the present invention. Although showing a grown state, it can be seen that the HSG is hardly grown on the upper portion of the cylinder structure.

As such, the present invention prevents the HSG from growing in the portion exposed to the CF plasma by performing the CF plasma treatment only on the upper portion of the cylinder structure. HSG grows by rearranging Si atoms in a hemispherical shape as they break and move Si-Si bonds. When carbon is injected into the interlayer insulating film surface, HSG causes Si-C bonds with a very strong bonding force to suppress HSG formation. .

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

For example, in the above-described embodiment, the case where the etchback process is performed for recessing the second PSG film and the amorphous silicon film is described as an example. However, the etchback process is replaced with a chemical mechanical polishing (CMP) process. The present invention may also be applied to the present invention, and the etching gas of the second PSG film and the amorphous silicon film used in the above-described embodiments may be replaced with other etching agents as necessary.

In addition, in the above-described embodiment, the plasma treatment using CF gas after etching back of the amorphous silicon film has been described as an example. However, the present invention uses a gas containing carbon, such as CF gas when etching back of the amorphous silicon film. This may also apply.

The present invention described above suppresses the growth of HSG on the cylinder structure of the charge storage electrode to prevent short circuits between the charge storage electrodes caused by the falling off of the HSG on the cylinder structure in a subsequent process, and suppresses particle generation by HSG. There is an effect, and thus it can be expected to improve the electrical properties and yield of the semiconductor device.

Claims (7)

Forming a contact hole through the predetermined interlayer insulating film to expose the semiconductor substrate; A second step of embedding a contact plug in the contact hole; A third step of forming a first sacrificial layer on the entire structure after the second step; A fourth step of selectively etching the first sacrificial layer in the region where the charge storage electrode is to be formed; A fifth step of forming an amorphous silicon film along the entire structure surface of the fourth step; A sixth step of forming a second sacrificial film on the amorphous silicon film; Recessing the second sacrificial layer to expose the amorphous silicon layer; An eighth step of recessing the exposed amorphous silicon film to expose the first sacrificial film; A ninth step of performing a plasma treatment using a gas containing carbon on the exposed amorphous silicon film; A tenth step of removing the first and second sacrificial layers; And An eleventh step of forming a selective hemispherical silicon grain on the exposed surface of the amorphous silicon film Method for forming a charge storage electrode of a semiconductor device comprising a. The method of claim 1, After performing the eleventh step, And a twelfth step of performing wet cleaning prior to forming the dielectric film. The method according to claim 1 or 2, The gas containing the carbon, A charge storage electrode forming method of a semiconductor device, characterized in that the CF-based gas. The method of claim 1, In the seventh step, A method of forming a charge storage electrode of a semiconductor device, comprising performing an etch back process or a chemical mechanical polishing process of the second sacrificial layer. The method of claim 1, In the eighth step, A method for forming a charge storage electrode of a semiconductor device, characterized in that for performing an etch back process or a chemical mechanical polishing process of the amorphous silicon film. The method according to claim 1 or 4, The first and second sacrificial layers, A method for forming a charge storage electrode of a semiconductor device, characterized in that the PSG (phosphosilicate glass) film. Forming a contact hole through the predetermined interlayer insulating film to expose the semiconductor substrate; A second step of embedding a contact plug in the contact hole; A third step of forming a first sacrificial layer on the entire structure after the second step; A fourth step of selectively etching the first sacrificial layer in the region where the charge storage electrode is to be formed; A fifth step of forming an amorphous silicon film along the entire structure surface of the fourth step; A sixth step of forming a second sacrificial film on the amorphous silicon film; Recessing the second sacrificial layer to expose the amorphous silicon layer; An eighth step of etching back the exposed amorphous silicon film using a gas containing carbon to expose the first sacrificial film; A ninth step of removing the first and second sacrificial layers; And A tenth step of forming selective hemispherical silicon grains on the exposed surface of the amorphous silicon film Method for forming a charge storage electrode of a semiconductor device comprising a.