KR100223286B1 - Method for manufacturing charge storage node of capacitor - Google Patents

Abstract

The present invention relates to a method of manufacturing a charge storage electrode of a capacitor.

In the present invention, after forming an oxide (or nitride) spacer on the polysilicon layer above the junction, an inner cylinder structure is formed by a polysilicon etching process using the same, and an oxide (or nitride) spacer is formed on the inner cylinder structure sidewall again. After that, by forming the outer cylinder structure by the polysilicon spacer forming process using the same, it is possible to maximize the effective surface area under a limited area.

Description

Method for manufacturing charge storage electrode of capacitor

1A to 1F are cross-sectional views of a device showing a step of manufacturing a charge storage electrode of a capacitor according to the present invention.

* Explanation of symbols for main parts of the drawings

1 semiconductor substrate 2 junction

3: interlayer insulating film 4: etching barrier layer

5: polysilicon layer 5A: inner cylinder structure

6: 1st groove 7: 1st spacer

8: 2nd groove 9: 2nd spacer

10 polysilicon spacer (outer cylinder structure) 11: undercut

The present invention relates to a method for manufacturing a charge storage electrode of a capacitor, and more particularly, to a method of manufacturing a double cylinder type (double cylinder type) charge storage electrode that can increase the capacitance by maximizing the effective surface area of the charge storage electrode.

In general, as the semiconductor devices are highly integrated, the area occupied by the charge storage electrodes is decreasing. However, since a minimum capacitance for operating the device must be secured, there is a limit to forming the charge storage electrode small, and thus there is a limit to the high integration of the device. In order to solve this problem, various charge storage electrodes having a three-dimensional structure having the maximum effective surface area under a limited area have been studied.

Accordingly, in the present invention, after forming an oxide (or extinguishing) spacer on the polysilicon layer above the junction, an inner cylinder structure is formed by a polysilicon etching process using the same, and an oxide (or nitride) spacer is formed on the inner cylinder structure sidewall again. After forming a, by forming the outer cylinder structure by the polysilicon spacer forming process using the same, an object of the present invention is to provide a method of manufacturing a double-cylindrical charge storage electrode that can maximize the effective surface area under a limited area.

In order to achieve the above object, a method of manufacturing a charge storage electrode of the present invention sequentially forms an interlayer insulating film and an etch barrier layer on a semiconductor substrate, and then forms contact holes on the junctions, and on the etch barrier layer including the contact holes. Forming a thick polysilicon layer, forming a first groove on a surface of the polysilicon layer above the junction, forming a first spacer on an inner wall of the first groove, and forming the first spacer In the anisotropic polysilicon etching process using an etching mask, the polysilicon layer is etched until a thin thickness remains on the etch barrier layer. Thus, the polysilicon layer inside the first spacer is etched to form a second recess. And a polysilicon layer under the first spacer remains to form an inner cylinder structure of the charge storage electrode; After forming the second spacer on the side wall of the inner cylinder structure, etching the exposed portion of the polysilicon layer using the first and second spacers as an etching mask, and the charge storage electrode of the second spacer side wall Forming a polysilicon spacer with an outer cylinder structure, and removing the first and second spacers by a wet etching process to manufacture a double cylinder type charge storage electrode having the inner cylinder structure and the outer cylinder structure. It features.

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

1A to 1F are cross-sectional views of a device showing a step of manufacturing a charge storage electrode of a capacitor according to the present invention.

In FIG. 1A, an interlayer insulating film 3 and an etching barrier layer 4 are sequentially formed on a semiconductor substrate 1, and a junction part 2 formed in the semiconductor substrate 1 is formed by a lithography process and an etching process using a contact mask. A contact hole is formed to be exposed, and a thick polysilicon layer 5 is formed on the etch barrier layer 4 including the contact hole.

The first groove 6 having the contact hole size is formed in the polysilicon layer 5 on the upper portion of the first groove or the junction 2, and the first spacer 7 is formed on the inner wall of the first groove 6 by oxide. One is shown.

In FIG. 1C, the polysilicon layer 5 is etched by the anisotropic polysilicon etching process using the first spacer 7 as an etch mask until a thin thickness remains on the etch barrier layer 4. As a result of the anisotropic polysilicon etching process, the polysilicon layer 5 inside the first spacer 7 is etched to form a second recess 8, and the polysilicon layer 5 under the first spacer 7. This remaining cylinder structure 5A of the charge storage electrode is formed.

After the oxide is deposited on the polysilicon layer 5 including the 1 d or the second recess 8, the spacer is etched to form the second spacer 9 on the sidewall of the inner cylinder structure 5A. The exposed portions of the polysilicon layer 5 are etched using the 1 and 2 spacers 7 and 9 as etch masks.

The polysilicon spacer 10 is formed on the sidewall of the second spacer 9 by depositing polysilicon on the etch barrier layer 4 including the first and second spacers 7 and 9. Formed to form the outer cylinder structure of the charge storage electrode is shown.

FIG. 1f illustrates the removal of the first and second spacers 7 and 9 by a wet etching process to produce a double cylinder type charge storage electrode composed of an inner cylinder structure 5A and an outer cylinder structure 10.

Meanwhile, in the embodiment of the present invention, the first and second spacers 7 and 9 are made of an oxide, and the etching barrier layer 4 is made of nitride. However, the first and second spacers 7 and 9 may be formed of nitride, and the etch barrier layer 4 is formed of an oxide. The etch barrier layer 4 may be deposited as hundreds of Å to simply serve as an etch barrier, and as the etch barrier layer 4 may be removed as a etch barrier as well as a wet etch method to form an under cut (11). can do.

As described above, the present invention forms an inner cylinder structure on the upper portion of the junction and an outer cylinder structure on the outer side of the inner cylinder structure to manufacture the double-cylinder type charge storage electrode, thereby maximizing the effective surface area under a limited area. It can contribute to the high integration of

Claims (5)

Sequentially forming an interlayer insulating film and an etching barrier layer on the semiconductor substrate on which the junction is formed, forming a contact hole to expose the junction, and then thickly forming a polysilicon layer on the entire structure including the contact hole; Forming a first groove on a surface of the polysilicon layer above the junction and forming a first spacer on an inner wall of the first groove; An anisotropic polysilicon etching process using the first spacer as a mask is etched such that the polysilicon layer remains thin on the etch barrier layer, thereby etching the polysilicon layer inside the first spacer to form a second recess. Is formed, and the polysilicon layer below the first spacer remains to form an inner cylinder structure; Forming a second spacer on a sidewall of the inner cylinder structure, and etching the exposed portion of the polysilicon layer using the first and second spacers as an etch mask; Forming a polysilicon spacer on the sidewalls of the second spacer to form an outer cylinder structure; And removing the first and second spacers by a wet etching process to manufacture a double cylinder type charge storage electrode having an inner cylinder structure and an outer cylinder structure. The method of claim 1, And removing the etch barrier layer by a wet etching method after the wet etching process of the first and second spacers to form an under cut. The method of claim 1, And the first and second spacers are formed using any one of an oxide and a nitride. The method of claim 1, When the first and second spacers are formed using an oxide, the etch barrier layer is formed using nitride, and when the first and second spacers are formed using a nitride, the etch barrier layer uses an oxide. The charge storage electrode manufacturing method of the capacitor, characterized in that formed by. The method of claim 1, The first recess is formed in the contact hole size, characterized in that the charge storage electrode manufacturing method of the capacitor.