KR20000045474A - Method for manufacturing decoupling capacitor of semiconductor device - Google Patents

Abstract

PURPOSE: A method for fabricating a decoupling capacitor of a semiconductor device is provided to improve the reliance and features of the semiconductor device by forming the decoupling capacitor to have an increased capacitance. CONSTITUTION: An isolation area and a decoupling capacitor forming area(200) are formed on a semiconductor substrate(31) by patterning a pad oxidized film(33) and a pad nitride film(35). A nitride film spacer is formed on a side wall of the structure consisting of the pad oxidized film(33) and the pad nitride film(35). An isolation film(39) is formed on the isolation area. By etching the nitride film spacer and the pad nitride film(35), the semiconductor substrate(31) corresponding to the decoupling capacitor forming area is exposed. Then, a plurality of trenches(41) are formed on the semiconductor substrate(31) corresponding to the decoupling capacitor area. After forming a gate oxidized film(43) and a conductive layer(45), the gate oxidized film(43) and the conductive layer(45) are patterned so that a gate electrode and a decoupling capacitor are provided.

Description

Decoupling Capacitor Formation Method of Semiconductor Device

The present invention relates to a method of forming a decoupling capacitor of a semiconductor device, and more particularly, to a technique of increasing the capacitance of a decoupling capacitor in order to minimize the decoupling of a word line.

All semiconductor devices have many circuits that generate internal voltages in addition to externally supplied voltages, and internal circuits operate with the voltages from the semiconductor devices. Such a phenomenon is a phenomenon in which semiconductor devices are highly integrated, and as the distance between conductive wirings increases, the number of times occurs.

In general, in the case of forming a semiconductor device by forming a device isolation film and a word line, forming a planarization insulating film, and then forming a bit line and performing a subsequent process, the semiconductor device is a dielectric material. Word lines and bit lines can be thought of as capacitors.

As a result of reading or writing data to an actual memory cell, a boosted voltage Vpp is applied to a word line of a selected cell, and as the cell transistor is turned on, the bit line becomes a bit line precharge voltage by an operation of a sense amplifier. It changes from Vblp to ground (0 V) or externally applied voltage (3.3 V). At this time, the word line of the unselected cell should be turned off (off) the cell transistor to the ground voltage, but the word line is decoupled according to the voltage change of the bit line to generate leakage current, that is, word line noise through the cell transistor.

In addition, defects may occur due to data loss of the cell capacitor, thereby deteriorating characteristics and reliability of the semiconductor device and consequently, high integration of the semiconductor device becomes difficult.

1A to 1D are cross-sectional views illustrating a method of forming a decoupling capacitor of a semiconductor device according to the prior art.

First, the pad oxide film 13 and the pad nitride film 15 are formed to have a predetermined thickness on the semiconductor substrate 11.

In addition, the device isolation region is exposed by etching the pad oxide layer 13 and the pad nitride layer 15 by the etching process using the device isolation mask (not shown). At this time, the stacking structure of the decoupling capacitor region 100 remains. (FIG. 1A)

The nitride film spacers 17 are formed on sidewalls of the pad oxide film 13 and the pad nitride film 15. (FIG. 1B)

Thereafter, the semiconductor substrate 11 is thermally oxidized to form an isolation layer 19 on the exposed surface of the semiconductor substrate 11. (FIG. 1C)

Then, the pad oxide film 13 and the pad nitride film 15 are removed, and a stacked structure of the gate oxide film 21 and the conductor for gate electrode 23 is formed on the entire surface.

A gate electrode is formed by etching the stacked structure of the gate oxide film 21 and the conductor 23 for a gate electrode using a gate electrode mask (not shown).

Here, the decoupling capacitor formation region 100 is formed in the same structure as the gate electrode formed in the active region of the semiconductor substrate 11. (FIG. 1D)

As described above, in the method of forming a decoupling capacitor of a semiconductor device according to the related art, a decoupling capacitor is formed in the same shape as that of the word line by connecting the word line to the outside of the semiconductor substrate to prevent the decoupling of the word line. There is a problem in that the decoupling phenomenon of the semiconductor device is inversely insufficient, which deteriorates the characteristic reliability of the semiconductor device.

The present invention is to solve the problem of the prior art, in order to prevent the decoupling phenomenon by forming a trench in the decoupling capacitor region to increase the capacitance of the capacitor to sufficiently prevent the decoupling of the word line of the semiconductor device An object of the present invention is to provide a method of forming a decoupling capacitor of a semiconductor device capable of improving characteristics and reliability.

1A to 1D are cross-sectional views illustrating a method of forming a decoupling capacitor of a semiconductor device according to the prior art.

2A to 2H are cross-sectional views illustrating a method of forming a decoupling capacitor of a semiconductor device in accordance with an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

11,31: semiconductor substrate 13,33: pad oxide film

15,35: pad nitride film 17,37: nitride film

19,39 Device isolation film 21,43 Gate oxide film

23,45: conductor for gate electrode 41: trench

100,200: decoupling capacitor formation area

In order to achieve the above object, a method of forming a decoupling capacitor of a semiconductor device according to the present invention,

Defining a device isolation region and a decoupling capacitor formation region by patterning the pad oxide layer and the pad nitride layer on the semiconductor substrate, wherein forming the pad oxide layer and the pad nitride layer stacked structure of the decoupling capacitor formation region in a plurality of patterns;

Forming a nitride film spacer on sidewalls of the pad oxide film and the pad nitride film stack structure;

Forming an isolation layer in the isolation region;

Exposing the surface of the semiconductor substrate of the decoupling capacitor formation region by etching the entire surface of the nitride film spacer and the pad nitride film;

Forming a plurality of trenches in the semiconductor substrate in the decoupling capacitor formation region using the nitride spacers, the pad nitride layers, and the isolation layers as masks;

Removing the nitride film spacer and the pad nitride film;

Forming a gate electrode and a decoupling capacitor by forming a gate oxide film and a conductor for the gate electrode on the surface of the semiconductor substrate.

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

2A to 2H are cross-sectional views illustrating a method of forming a decoupling capacitor of a semiconductor device in accordance with an embodiment of the present invention, and do not show an impurity implant process.

First, a pad oxide film 33 and a pad nitride film 35 are formed on the semiconductor substrate 31 at a predetermined thickness. In this case, the pad oxide film 33 is formed to a thickness of 50 ~ 100 GPa and the pad nitride film 35 is formed to a thickness of 900 ~ 2000 GPa.

In addition, the device isolation region is exposed by etching the pad oxide layer 33 and the pad nitride layer 35 by an etching process using an element isolation layer mask (not shown), and the layer structure of the decoupling capacitor formation region is spaced at a predetermined interval. To form a plurality of patterns having. At this time, a predetermined interval of the laminated structure formed in the decoupling capacitor formation region is about 300 to 1000 Å. (FIG. 2A)

Next, a nitride film 37 is formed on the entire surface to a thickness of 200 to 500 Å and anisotropically etched to form a nitride film 37 spacer on the sidewalls of the pad oxide film 33 and the pad nitride film 35. (FIG. 2B, FIG. 2C)

The semiconductor substrate 31 is thermally oxidized to form an isolation layer 39 in the isolation region. (FIG. 2D)

Subsequently, the pad nitride layer 35 and the nitride layer 37 spacers are etched by using the difference in the etch selectivity between the device isolation layer 39, the pad nitride layer 35, and the nitride layer 37 spacers to form the decoupling capacitor formation region. The semiconductor substrate 31 is exposed at regular intervals between the stacked structures of 200, with a spacing of 300 to 700 Å. (FIG. 2E)

The semiconductor substrate 31 is etched using the pad oxide layer 33 and the pad nitride layer 35 as a mask to form a plurality of trenches 41 in the decoupling capacitor formation region 200. At this time, the trench 41 is formed to a depth of 300 ~ 2000Å. (FIG. 2F)

Next, the pad oxide film 33 and the pad nitride film 35 stacked structure and the nitride film 37 spacer are removed, and the gate oxide film 43 and the gate electrode conductive on the surface of the semiconductor substrate 31 including the trench 41 are removed. After the sieve 45 is formed, the gate electrode conductor 45 is patterned by an etching process using a gate electrode mask (not shown) to form a gate electrode and a decoupling capacitor. (FIG. 2G, FIG. 2H)

As described above, the method of forming a decoupling capacitor of a semiconductor device according to the present invention increases the capacitance of the decoupling capacitor to prevent decoupling of the gate electrode, that is, the word line, thereby removing noise and reducing leakage current, thereby reducing the leakage current of the semiconductor device. There is an effect that can improve the characteristics and reliability.

Claims (7)

Defining a device isolation region and a decoupling capacitor formation region by patterning the pad oxide layer and the pad nitride layer on the semiconductor substrate, wherein forming the pad oxide layer and the pad nitride layer stacked structure of the decoupling capacitor formation region in a plurality of patterns; Forming a nitride film spacer on sidewalls of the pad oxide film and the pad nitride film stack structure; Forming an isolation layer in the isolation region; Exposing the surface of the semiconductor substrate of the decoupling capacitor formation region by etching the entire surface of the nitride film spacer and the pad nitride film; Forming a plurality of trenches in the semiconductor substrate in the decoupling capacitor formation region using the nitride spacers, the pad nitride layers, and the isolation layers as masks; Removing the nitride film spacer and the pad nitride film; Forming a gate electrode and a decoupling capacitor by forming a gate oxide film and a conductor for the gate electrode on the surface of the semiconductor substrate, and forming the gate electrode and the decoupling capacitor. The method of claim 1, The pad oxide film has a thickness of 50 to 100 GPa, the method of forming a decoupling capacitor of a semiconductor device. The method of claim 1, The pad nitride film is a method of forming a decoupling capacitor of a semiconductor device, characterized in that formed in a thickness of 900 ~ 2000Å. The method of claim 1, And a plurality of patterns each having a pad oxide film and a pad nitride film stacked structure in the decoupling capacitor formation region at intervals of 300 to 1000 microseconds. The method of claim 1, The nitride film spacer is a method of forming a decoupling capacitor of a semiconductor device, characterized in that formed in a thickness of 200 to 500 kHz. The method of claim 1, A method of forming a decoupling capacitor of a semiconductor device, characterized in that the semiconductor substrate in the decoupling capacitor formation region is exposed to a width of 300 to 700 으로 by the front etching process of the pad oxide film, the pad nitride film, and the nitride film spacer. The method of claim 1, The trench is a method of forming a decoupling capacitor of a semiconductor device, characterized in that formed in a depth of 300 ~ 2000Å.