KR20040006146A - Forming method for storage node of semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing a storage node of a semiconductor device is provided to prevent bridge between storage nodes by forming a spacer having different etching selectivity compared to a core insulating layer at inner walls of a trench. CONSTITUTION: A lower insulating layer having a storage node contact plug(19) is formed on a substrate(11). A core insulating layer and an anti-reflective layer are sequentially formed on the resultant structure. A trench is formed to expose the storage node contact plug(19). A spacer(27) having a relatively high etching selectivity compared to the core insulating layer is formed at inner walls of the trench. A conductive layer and a sacrificial layer are formed in the trench. By planarizing the sacrificial layer, the conductive layer and the anti-reflective layer, a storage node(30) is then formed.

Description

Forming method for storage node of semiconductor device

The present invention relates to a method of forming a storage electrode of a semiconductor device, and more particularly, to a method of forming a storage electrode of a semiconductor device by maintaining a distance between the storage electrodes to prevent a bridge between the storage electrodes.

Recently, due to the trend toward higher integration of semiconductor devices, it is difficult to form capacitors with sufficient capacitance due to a decrease in cell size. In particular, a DRAM device including one MOS transistor and a capacitor has a word in a vertical and horizontal direction on a semiconductor substrate. Lines and bit lines are orthogonally arranged, a capacitor is formed over two gates, and a contact hole is formed in the center of the capacitor.

In this case, the capacitor mainly uses an oxide film, a nitride film, or an O.O. (oxide-nitride-oxide) film as a dielectric, using polycrystalline silicon as a conductor, and a capacitance of a capacitor that occupies a large area in a chip. While reducing the area, reducing the area becomes an important factor in the high integration of the DRAM device.

Therefore, C = (ε0 × εr × A) / T, where ε0 is the permittivity of vacuum, εr is the dielectric constant of the dielectric film, A is the surface area of the capacitor, and T is the thickness of the dielectric film. In order to increase the capacitance C of the displayed capacitor, a material having a high dielectric constant is used as the dielectric, a thin dielectric film is formed, or the surface area of the capacitor is increased.

Hereinafter, although not shown, a method of forming a storage electrode of a semiconductor device according to the related art will be described.

First, an isolation layer for defining an active region is formed on a semiconductor substrate.

Next, a gate insulating film is formed on the semiconductor substrate, a transistor including a gate electrode and a source / drain junction region, a lower structure such as a landing plug and a bit line is formed, and an interlayer insulating film is formed on the entire surface.

Next, an etch stop layer and a buffer layer are formed on the interlayer insulating layer. In this case, the etch stop film is formed of a nitride film, the interlayer insulating film and the buffer film is formed of an oxide film.

Next, the buffer layer, the etch stop layer and the interlayer insulating layer are etched by a photolithography process using a storage electrode contact mask to form a storage electrode contact hole.

A storage electrode contact plug is then formed to fill the storage electrode contact hole.

Next, a core insulating film is formed over the entire surface. In this case, the core insulating film is formed of an oxide film such as PSG (phospho silicate glass) or USG (undoped silicate glass).

Next, an antireflection film is formed on the core insulation film. In this case, the anti-reflection film is formed of an oxynitride film (SiON).

Next, a trench for exposing the storage electrode contact plug is formed by etching the anti-reflection film and the core insulation layer by a photolithography process using a storage electrode mask. In the etching process, excessive etching is possible as much as the thickness of the buffer layer.

Thereafter, the conductive layer for the storage electrode is formed to have a predetermined thickness on the entire surface. In this case, the storage electrode conductive layer is formed of a polycrystalline silicon layer.

Next, a sacrificial insulating film is formed over the entire surface. In this case, the sacrificial insulating film is formed of a material having excellent fluidity, such as a photosensitive film, and is formed so as to completely fill the trench.

Next, the sacrificial insulating film, the conductive layer for the storage electrode, and the anti-reflection film are removed by a chemical mechanical polishing (CMP) process to form a cylindrical storage electrode. In this case, the CMP process may be performed until the core insulation layer is exposed to remove the core insulation layer in a subsequent process.

Next, the sacrificial insulating film and the core insulating film remaining in the storage electrode are removed to expose the surface of the storage electrode.

Thereafter, hemispherical silicon is grown on the surface of the storage electrode to increase the surface area of the storage electrode.

Next, a conductive layer for the dielectric film and the plate electrode is formed on the entire surface, and the conductive layer and the dielectric film for the plate electrode are etched by a photolithography process using a plate electrode mask to complete the capacitor.

As described above, in the method of forming a storage electrode of a semiconductor device according to the related art, when a semiconductor device is highly integrated, a gap between the devices is narrowed to form a hemispherical silicon to increase the surface area of the storage electrode. ) Is generated to lower the insulation characteristics between the devices, thereby lowering the reliability and yield of the devices.

In order to solve the above problems of the prior art, a trench is formed by etching a core insulating layer, and then spacers are formed on the sidewalls of the trench by using an insulating layer having an etching selectivity difference from the core insulating layer. Method of forming a storage electrode of a semiconductor device to increase the distance to prevent the bridge between the storage electrodes even after forming the hemispherical silicon on the surface of the storage electrode to improve the insulating properties between the storage electrodes, thereby improving the high integration of the semiconductor device The purpose is to provide.

1 to 3 are cross-sectional views illustrating a method of forming a storage electrode of a semiconductor device according to the present invention.

<Description of Symbols for Major Parts of Drawings>

11 semiconductor substrate 13 interlayer insulating film

15: etching prevention film 17: buffer film

19: storage electrode contact plug 21: core insulating film

23: antireflection film 25: photosensitive film pattern

27 insulating film spacer 29 conductive layer for storage electrode

30: storage electrode 31: hemispherical silicon

Method for forming a storage electrode of a semiconductor device according to the present invention for achieving the above object,

Forming a lower insulating layer having a storage electrode contact plug on the semiconductor substrate having a predetermined lower structure;

Sequentially forming a core insulating film and an antireflection film on the entire surface;

Forming a trench to expose the storage electrode contact plug by etching the anti-reflection film and the core insulating film by a photolithography process using a storage electrode mask;

Forming a spacer on a sidewall of the trench by using an insulating film having an etch selectivity difference from the core insulating film;

Forming a conductive layer for a storage electrode on the entire surface;

Forming a sacrificial insulating film on the conductive layer for the storage electrode;

Forming a storage electrode by planarizing etching the sacrificial insulating film, the conductive layer for the storage electrode, and the anti-reflection film;

Removing the sacrificial insulating film and the core insulating film;

Forming hemispherical silicon on the surface of the storage electrode;

The lower insulating film is a laminated structure of an interlayer insulating film, an etch stop film and a buffer film,

The etch stop layer is formed of a nitride film,

The buffer film is formed of a high temperature oxide film,

The core insulating film is formed of a PSG film or USG film,

The anti-reflection film is formed of an oxynitride film,

The spacer is formed by depositing the PSG film to a thickness of 500 ~ 1500Å after the entire surface etching,

The sacrificial insulating film is characterized in that the photosensitive film.

Hereinafter, a method of forming a storage electrode of a semiconductor device according to the related art will be described with reference to the accompanying drawings.

1 to 3 are cross-sectional views illustrating a method of forming a storage electrode of a semiconductor device according to the present invention.

First, an element isolation insulating film (not shown) defining an active region is formed on the semiconductor substrate 11.

Next, a gate insulating layer (not shown) is formed on the semiconductor substrate 11, and a transistor including a gate electrode (not shown) and a source / drain junction region (not shown), a landing plug (not shown), and a bit line ( An interlayer insulating film 13 is formed over the entire surface after forming the lower structure.

Next, an etch stop layer 15 and a buffer layer 17 are formed on the interlayer insulating layer 13. In this case, the etch stop layer 15 is formed of a nitride film, the interlayer insulating layer 13 and the buffer layer 17 is formed of an oxide film. In particular, the buffer layer 17 is formed of a high temperature oxide layer.

Next, the buffer layer 17, the etch stop layer 15, and the interlayer insulating layer 13 are etched by a photolithography process using a storage electrode contact mask to form a storage electrode contact hole (not shown).

Next, a storage electrode contact plug 19 filling the storage electrode contact hole is formed.

Next, a core insulating film 21 is formed over the entire surface. In this case, the core insulating layer 21 is formed of an oxide film such as a phospho silicate glass (PSG) film or an undoped silicate glass (USG) film.

Next, an anti-reflection film 23 is formed on the core insulation film 21. In this case, the anti-reflection film 23 is formed of an oxynitride film (SiON).

Next, a photoresist (not shown) is applied over the entire surface.

Thereafter, the photoresist film is exposed and developed by a photolithography process using a storage electrode contact mask to form a photoresist pattern 25. (See Figure 1)

Next, the anti-reflection film 23 and the core insulating layer 21 are etched using the photoresist pattern 25 as an etch mask to form a trench (not shown) to expose the storage electrode contact plug 19. In the etching process, excessive etching is possible by the thickness of the buffer layer 17.

Thereafter, the photosensitive film pattern 25 is removed.

Then, an insulating film (not shown) of a predetermined thickness is deposited on the entire surface. In this case, the insulating film is formed to have a thickness of 500 to 1500 Å using a PSG film or a USG film having a difference in etching selectivity from the core insulating film 21 and the buffer film 17. In this case, when the PSG film is used, the etching selectivity difference is remarkable when the impurity concentration is changed.

Next, the insulating layer is entirely etched to form insulating layer spacers 27 on the sidewalls of the trench.

Thereafter, the conductive layer 29 for the storage electrode is formed to have a predetermined thickness on the entire surface. In this case, the storage electrode conductive layer 29 is formed of a polysilicon layer. (See Figure 2)

Next, a sacrificial insulating film (not shown) is formed over the entire surface. In this case, the sacrificial insulating film is formed of a photoresist film, and the trench is completely filled.

Next, the sacrificial insulating film, the storage electrode conductive layer 29 and the anti-reflection film 23 are removed by the CMP process to form the cylindrical storage electrode 30. In this case, the CMP process may be performed until the core insulation layer 21 is exposed so that the core insulation layer 21 may be removed in a subsequent process.

Next, the sacrificial insulating film and the core insulating film 21 remaining in the storage electrode 30 are removed to expose the surface of the storage electrode 30. In this case, the core insulating layer 21 and the insulating layer spacer 27 are formed of a material having a difference in etching selectivity, so that the insulating layer spacer 27 remains on the sidewall of the storage electrode 30 even after the core insulating layer 21 is removed. The remaining distance between the storage electrodes 30 is maintained.

Thereafter, hemispherical silicon 31 is grown on the surface of the storage electrode 30 to increase the surface area of the storage electrode 30. In this case, since the insulating layer spacer 27 is provided on the outer sidewall of the storage electrode 30 to maintain a predetermined distance between the storage electrodes 30, even if the hemispherical silicon 31 is formed on the storage electrode 30. There is no fear of causing a bridge with the storage electrode 30. (See Figure 3)

Next, a conductive layer for the dielectric film and the plate electrode is formed on the entire surface, and the conductive layer and the dielectric film for the plate electrode are etched by a photolithography process using a plate electrode mask to complete the capacitor.

As described above, in the method of forming the storage electrode of the semiconductor device according to the present invention, a trench is formed by etching a core insulating layer, and then spacers are formed on the sidewall of the trench by using an insulating layer having an etch selectivity difference between the core insulating layer and a trench. As a result, even after the hemispherical silicon is formed on the surface of the storage electrode, bridges are prevented from occurring between the storage electrodes, thereby improving insulating properties between the storage electrodes, thereby improving the integration of semiconductor devices.

Claims (8)

Forming a lower insulating layer having a storage electrode contact plug on the semiconductor substrate having a predetermined lower structure; Sequentially forming a core insulating film and an antireflection film on the entire surface; Forming a trench to expose the storage electrode contact plug by etching the anti-reflection film and the core insulating film by a photolithography process using a storage electrode mask; Forming a spacer on a sidewall of the trench by using an insulating film having an etch selectivity difference from the core insulating film; Forming a conductive layer for a storage electrode on the entire surface; Forming a sacrificial insulating film on the conductive layer for the storage electrode; Forming a storage electrode by planarizing etching the sacrificial insulating film, the conductive layer for the storage electrode, and the anti-reflection film; Removing the sacrificial insulating film and the core insulating film; And forming a hemispherical silicon on the surface of the storage electrode. The method of claim 1, And the lower insulating layer is a stacked structure of an interlayer insulating layer, an etch stop layer and a buffer layer. The method of claim 2, The etch stop layer is a storage electrode forming method of a semiconductor device, characterized in that formed of a nitride film. The method of claim 2, The buffer film is a storage electrode forming method of a semiconductor device, characterized in that formed by a high temperature oxide film. The method of claim 1, The core insulation layer is formed of a PSG layer or a USG layer. The method of claim 1, The anti-reflection film is a storage electrode forming method of a semiconductor device, characterized in that formed of oxynitride film. The method of claim 1, The spacer is formed by depositing a PSG film or USG film to a thickness of 500 ~ 1500Å by etching the entire surface of the semiconductor device. The method of claim 1, And the sacrificial insulating film is a photosensitive film.