KR0137976B1 - Fabrication method of electrode in semiconductor device - Google Patents

Abstract

The present invention relates to a storage electrode of a semiconductor device and a method of manufacturing the same. In the prior art, a bit line is formed on a drain electrode formed on an upper surface of a semiconductor substrate, and a conductive layer for a first storage electrode is formed on a source electrode. After forming a sacrificial film having a high stepped fence pillar shape and forming a conductive layer spacer for the second storage electrode on the sidewall of the fence pillar, the lower sacrificial film is etched using the conductive layer spacer for the second storage electrode as a mask. After forming a sacrificial layer pattern and depositing a conductive layer for a third storage electrode on the entire structure, and then anisotropically etching the conductive layer for the third storage electrode to form a conductive layer spacer for the third storage electrode. The conductive layer spacer for the second storage electrode and the conductive layer for the first storage electrode are exposed and anisotropically etched by the exposed thickness of the conductive layer for the first storage electrode. The sacrificial layer pattern is exposed by anisotropically etching the conductive layer spacers for the second and third storage electrodes, and then the sacrificial layer pattern is removed by a wet method to maximize the storage area of the storage electrode by maximizing the surface area and the integration degree of the semiconductor device. To improve the technology.

Description

Storage electrode of semiconductor device and manufacturing method thereof

1 to 4 are cross-sectional views and plan views showing a storage electrode forming process of a semiconductor device according to the present invention.

* Code descriptions for the main parts of the drawings

1: semiconductor organ 2: device isolation insulating film

3: gate oxide film 4: gate electrode

5: source electrode 5 ': drain electrode

6: interlayer insulating film pattern 7: conductive layer for first storage electrode

8 ': sacrifice pattern

9: conductive layer spacer for second storage electrode

9 ': conductive layer spacer for roof-shaped second storage electrode

10: conductive layer for the third storage electrode

11: step

13,15: conductive layer spacer for second storage electrode

20: storage electrode contact hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage electrode of a semiconductor device and a method of manufacturing the same, and more particularly, to a technique of increasing a surface area of a storage electrode and forming a capacitor in a subsequent process in order to secure capacitance of a highly integrated semiconductor device.

As DRAMs become highly integrated, the cell area is drastically reduced, and despite the reduction in cell area, sufficient surface area of the storage electrode must be obtained in a given area in order to secure a capacitor capacity of a certain capacity per cell required for device operation.

Fin structure among various 3D storage electrodes developed to solve these difficulties has been widely used because its manufacturing process is relatively simple, but it is necessary to increase the number of fins to secure a constant capacitor capacity as the cell area is reduced. In order to increase the number of the fins, the DVD oxide film as the oxide film and the polysilicon film as the electrically conductive thin film must be repeatedly formed, thereby increasing the number of processes and increasing particles and defects caused by many CVD processes. Lowers the resulting yield.

As described above, the fin-type structure according to the related art has a problem in that particles and defects caused during the manufacturing process of the storage electrode are increased, thereby deteriorating characteristics and reliability of the semiconductor device.

Accordingly, the present invention maximizes the area where the storage electrode is formed by minimizing the distance between neighboring charge holding electrodes to less than the minimum size in the photolithography technique, in order to solve the above problems of the prior art, It is an object of the present invention to provide a storage electrode of a semiconductor device and a method of manufacturing the same, forming a capacitor having a capacitance sufficient for high integration of a semiconductor device by forming a structure of a shape of a fence and a roof of more than one.

In order to achieve the above object, the storage electrode of the semiconductor device according to the present invention,

A storage electrode of a semiconductor device, in which a bit line is connected to a drain electrode and a storage electrode is connected to a source electrode,

Double fence-type storage electrodes having different heights are formed in one unit cell, and the double fence-type storage electrodes are connected to each other at a lower portion thereof.

Of the double fence is provided with a storage electrode of the roof shape connected to the upper storage electrode of the high fence type,

The roof-type storage electrode may be provided separately from the fence-type storage electrode having a low height among the double fences.

In order to achieve the above object, a storage electrode manufacturing method of a semiconductor device according to the present invention includes:

Forming a sacrificial film having a high step on the upper side of the conductive layer for the first storage electrode connected to the semiconductor substrate in the shape of a fence pillar;

Forming a conductive layer spacer for a second storage electrode on the pillar-shaped sidewall;

Forming a sacrificial layer pattern under the second storage electrode conductive layer spacer by etching the sacrificial layer by using the second storage electrode conductive layer spacer as a mask;

Depositing a predetermined thickness of the conductive layer for the third storage electrode on the entire structure;

Anisotropically etching the conductive layer for the third storage electrode to expose the conductive layer for the first storage electrode and to form the conductive layer spacer for the third storage electrode;

Anisotropically etch all the storage electrode conductive layers including the exposed conductive layer for the first storage electrode to form a conductive layer pattern for the first storage electrode and at the same time conduct the spacer for the third storage electrode conductive layer spacer and the second storage electrode. Anisotropically etching the layer spacers to form a conductive layer spacer for the roof type second storage electrode exposing the sacrificial layer pattern;

And removing the sacrificial film pattern by a wet method.

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

1 to 4 are cross-sectional views illustrating a process of forming a storage electrode of a semiconductor device in accordance with some embodiments of the present invention, and FIGS. 2A and 4A are plan views illustrating FIGS. 2 and 4.

First, a device isolation insulating film 2, a gate oxide film 3, a gate electrode 4 and a source and a drain electrode 5, 5 'are formed on a predetermined portion of the semiconductor substrate 1, and the interlayer insulating film ( Forming a bit line (not shown) connected to the drain electrode (5 ') after etching the interlayer insulating film to form a bit line (not shown), and forming a storage electrode. After forming the interlayer insulating film pattern 6, a storage electrode contact hole 20 exposing the source electrode 5 is formed and connected to the source electrode 5 through the storage electrode contact hole 20. After forming the conductive layer 7 for the first storage electrode to be formed to a predetermined thickness, the sacrificial layer 8 is formed thick on the conductive layer 7 for the first storage electrode, but a high step 11 is formed at a predetermined portion. The first storage electrode conductive layer 7 is a polysilicon film or an amorphous layer. (Amorphouse) it can be used a silicon film, the sacrificial film 8 can be formed by using an oxide film.

In addition, unlike a process sequence in which a storage electrode is formed on a source electrode after a bit line is connected to the drain electrode 5 ', a storage electrode connected to the source electrode 5 is first formed, and then the drain electrode 5' is formed. May be formed.

(First degree)

Subsequently, a second storage electrode conductive layer is deposited on the sacrificial layer 8 having a high step 11 formed thereon in a columnar shape, and then the conductive layer spacer 9 for the second storage electrode is anisotropically etched. It is sectional drawing which formed. The second storage electrode conductive layer spacer 9 may be a polysilicon film or an amorphous silicon film.

At this time, the conductive layer spacer 9 for the second storage electrode 9 is formed in a fence shape around the sacrificial layer 8 having a high step 11 formed in a rectangular pillar at a predetermined portion.

(Second, 2A)

Next, the sacrificial layer 8 is etched using the second storage electrode conductive layer spacer 9 as a mask to form a sacrificial layer pattern 8 ′ under the second storage electrode conductive layer 9. After the formation, the conductive layer 10 for the third storage electrode is deposited to a predetermined thickness on the entire upper structure.

In this case, the third storage electrode conductive layer 10 is formed using a polycrystalline silicon film or an amorphous silicon film. (Third degree)

Then, the third storage electrode conductive layer 10 is anisotropically etched to form a third storage electrode conductive layer spacer (not shown), and then all exposed portions including the first storage electrode conductive layer 7 are formed. Anisotropically etching the storage electrode conductive layers 7, 9, and 10 to form the first storage electrode conductive layer pattern 7 ′, and simultaneously forming the third storage electrode conductive layer spacers 13, 15. As the second storage electrode conductive layer spacer 9 is anisotropically etched, the second storage electrode conductive layer spacer 9 'becomes a roof-shaped second conductive electrode spacer 9', and at the same time, the sacrificial layer pattern 8 'is exposed to expose the sacrificial layer pattern ( 8 ') is removed by a wet method to form a storage electrode with a maximum surface area.

At this time, the storage electrode is formed from the conductive layer spacer 13 for the third storage electrode, the conductive layer pattern 7 'for the first storage electrode, the conductive layer spacer 9' for the second storage electrode, and the roof shape. 3 is formed on the upper portion of the interlayer insulating film pattern 6 in the shape of a fence in the order of the conductive layer spacer 15 for the storage electrode (FIGS. 4 and 4A).

According to the present invention, by minimizing the distance between the adjacent storage electrodes to less than the minimum size in the photo-shape technology to maximize the area where the storage electrode is formed and maximize the surface area of the storage electrode, it is possible to maximize the storage capacity The yield and the degree of integration of the semiconductor device can be improved.

Claims (6)

In a storage electrode of a semiconductor device in which a bit line is connected to a drain electrode and a storage electrode is connected to a source electrode, a double fence-type storage electrode having different heights is formed in one unit cell, and the double fence-type storage electrode is formed. Storage electrodes are connected to each other at the bottom and provided with a roof-type storage electrode connected to an upper portion of the fence-type storage electrode of the height of the double fence, the roof-type storage electrode is a low height of the double fence Storage electrode of the device on the peninsula, characterized in that provided separately from the fence-type storage electrode. Forming a sacrificial film having a high step on the upper side of the first storage electrode connected to the semiconductor substrate in the shape of a fence pillar; forming a conductive layer spacer for the second storage electrode on the sidewall of the column; Forming a sacrificial layer pattern under the second storage electrode conductive layer spacer by etching the sacrificial layer by using the conductive layer spacer for the second storage electrode as a mask; and conducting the third storage electrode conductive on the entire structure. Depositing a predetermined thickness of the layer, anisotropically etching the conductive layer for the third storage electrode, exposing the conductive layer for the first storage electrode, and forming the conductive layer spacer for the third storage electrode; Anisotropically etch all the storage layer conductive layers including the conductive layer for the first storage electrode to form the conductive pattern for the first storage electrode and at the same time the conductive layer spacer for the third storage electrode. And anisotropically etching the second storage electrode conductive layer spacer to form a roof-type second storage electrode conductive layer spacer exposing the sacrificial layer pattern, and removing the sacrificial layer pattern by a wet method. Method of manufacturing a storage electrode. The method of claim 2, wherein the first, second, and third storage electrode conductive layers are formed using an amorphous silicon film or a polycrystalline silicon film. The method of claim 2, wherein after forming the bit line on the drain electrode, the storage electrode is first formed on the source electrode and the bit line is formed on the drain electrode later in the reverse order of forming the storage electrode on the source electrode. A storage electrode manufacturing method of a semiconductor device. The method of claim 2, wherein the roof-shaped conductive layer spacer for the second storage electrode is connected to an outer fence of the conductive layer spacer for the third storage electrode. The method of claim 2, wherein the roof-type conductive layer spacer for the second storage electrode is connected to an inner wall of the conductive layer spacer for the third storage electrode.