KR20090113003A - Isolation layer of semiconductor device and method for forming the same - Google Patents

Abstract

PURPOSE: An isolation layer of a semiconductor device and a method for forming the same are provided to improve a hot carrier property at a peri region by forming a thick side wall oxide film at a peri region. CONSTITUTION: An isolation layer of a semiconductor device and a method for forming the same are composed of a semiconductor substrate(100), a side wall insulating film, and an insulating layer(112). A trench is equipped at the semiconductor substrate, and the side wall insulating film is formed on the surface of the trench. The insulating layer is formed on the side wall oxide to bury the trench on it.

Description

Isolation layer of semiconductor device and forming method thereof {ISOLATION LAYER OF SEMICONDUCTOR DEVICE AND METHOD FOR FORMING THE SAME}

The present invention relates to a device isolation film of a semiconductor device and a method of forming the same. More particularly, the device isolation film of the semiconductor device and the device that can improve the gap-fill characteristics of the cell region and also improve the hot carrier characteristics of the ferry region It relates to a formation method.

As is well known, during the fabrication of a semiconductor device, a process of forming an isolation layer (hereinafter, referred to as an isolation layer) for electrical separation between the elements is essential, and as a method of forming the isolation layer, a STI process is usually performed. This is being applied.

Hereinafter, a method of forming an isolation layer of a semiconductor device according to the related art using the STI process will be described briefly.

After the hard mask film pattern is formed on the semiconductor substrate, the semiconductor substrate portion is etched using the hard mask film pattern as an etching mask to form a trench. Subsequently, a sidewall oxide film is formed on the surface of the trench, and then an insulating film is formed to fill the trench on the semiconductor substrate on which the sidewall oxide film is formed.

Then, the insulating film is subjected to chemical mechanical polishing (CMP) until the hard mask film pattern is exposed, and then the hard mask film pattern is removed to form an isolation layer defining an active region in the trench of the semiconductor substrate.

On the other hand, with the advance of semiconductor technology, high speed and high integration of semiconductor devices are rapidly progressing, and as a result, the aspect ratio of the trench is increased, which makes the gap-fill process of the insulating film difficult. I lost.

Accordingly, various researches and developments are being made on a method for easily filling an insulating film in the trench, and as a part thereof, a sidewall oxide film formed on the surface of the trench to improve gap-fill characteristics of the insulating film. A method of forming a thin thickness has been proposed.

However, in the prior art described above, due to the thin-walled sidewall oxide film formed on the trench surface of the ferry region, damage by hot carriers in the ferry region is increased. Therefore, the method of reducing the thickness of the sidewall oxide film described above is limited to be applied to the ferry area.

The present invention provides a device isolation film of a semiconductor device and a method of forming the same that can improve the gap-fill characteristics of a cell region.

The present invention also provides a device isolation film of a semiconductor device and a method for forming the same, which can improve hot carrier characteristics in a ferry region.

An isolation layer of a semiconductor device according to an embodiment of the present invention may include a semiconductor substrate provided with a trench; A sidewall insulating film formed on a surface of the trench; And an insulating film formed to fill the trench on the sidewall oxide film, wherein the sidewall oxide film has a thicker thickness in the ferry area than in the cell area.

The sidewall insulating film is made of an oxide film.

The sidewall insulating film has a thickness of 5 to 200 Å thicker in the ferry region than in the cell region.

A method of forming a device isolation layer of a semiconductor device according to an embodiment of the present invention may include forming trenches in each region by etching a semiconductor substrate including a cell region and a ferry region; Forming a sidewall insulating film on the surface of the trench having a thicker thickness in the ferry region than in the cell region; And forming an insulating film to fill the trench on the sidewall insulating film.

The sidewall insulating film is formed of an oxide film.

The sidewall insulating film is formed to have a thickness of 5 to 200 Å thicker in the ferry region than in the cell region.

The forming of the sidewall insulating film may include forming a first sidewall insulating film on a surface of the trench; Forming a mask pattern exposing a cell region on the semiconductor substrate on which the first sidewall insulating film is formed; Removing a first sidewall insulating film of the exposed cell area; Removing the mask pattern; And forming a second sidewall insulating film on the first sidewall insulating film of the ferry region and a trench surface of the cell region.

The forming of the sidewall insulating film may include forming a first sidewall insulating film on a surface of the trench; Forming a mask pattern exposing a ferry region on the semiconductor substrate on which the first sidewall insulating film is formed; Forming a second sidewall insulating film on the first sidewall insulating film of the exposed ferry region; And removing the mask pattern.

The forming of the sidewall insulating layer may include forming a mask pattern exposing a ferry region on the trench formed semiconductor substrate; Performing oxygen ion implantation into the exposed ferry area; Removing the mask pattern; And performing an oxidation process on the semiconductor substrate from which the mask pattern is removed.

The forming of the sidewall insulating layer may include forming a mask pattern exposing a cell region on the semiconductor substrate on which the trench is formed; Performing nitrogen ion implantation into the exposed cell region; Removing the mask pattern; And performing an oxidation process on the semiconductor substrate from which the mask pattern is removed.

The mask pattern is formed of a nitride film or a photosensitive film.

The present invention can improve the gap-fill characteristics in the cell region and the hot carrier characteristics in the ferry region by forming a sidewall oxide film having a thicker thickness in the ferry region than the cell region on the surface of the trench. have.

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

1 is a cross-sectional view illustrating a device isolation film of a semiconductor device according to an embodiment of the present invention.

As shown, first and second trenches T1 and T2 in the cell region C and the ferry region P of the semiconductor substrate 100 including the cell region C and the ferry region P, respectively. Is formed. First and second sidewall insulating layers 108 and 110 are formed on surfaces of the first and second trenches T1 and T2, respectively, and the first and second sidewall insulating layers 108 and 110 are respectively formed on the surfaces of the first and second trenches T1 and T2. And an insulating film 112 so as to fill the second trenches T1 and T2. The first and second sidewall insulating films 108 and 110 and the insulating film 112 are formed of, for example, oxide films. Here, the second sidewall insulating film 110 formed in the ferry region P has a thickness that is thicker than the first sidewall insulating film 108 formed in the cell region C, preferably 5 to 200 ∼ thick. (W1 <W2)

Meanwhile, a liner insulating film (not shown) may be formed between the first and second sidewall insulating films 108 and 110 and the insulating film 112, and the liner insulating film may include, for example, at least one of a nitride film and an oxide film. It has a structure.

As described above, the device isolation film of the semiconductor device according to the embodiment of the present invention includes a second sidewall insulating film 110 formed in the ferry region P to have a thickness thicker than that of the cell region C. The present invention can improve the gap-fill characteristics in the cell region (C) and also improve the hot carrier characteristics in the ferry region (P).

2A to 2E are cross-sectional views illustrating processes of forming a device isolation film of a semiconductor device according to a first exemplary embodiment of the present invention.

Referring to FIG. 2A, a pad oxide film 202 and a pad nitride film 204 are sequentially formed on a semiconductor substrate 200 including a cell region C and a ferry region P. Referring to FIG. The pad nitride layer 204 and the pad oxide layer 202 are etched to expose portions of the semiconductor substrate 200, and then the exposed portions of the semiconductor substrate 200 are etched to expose the cell regions C and the semiconductor substrate 200. First and second trenches T1 and T2 are formed in the ferry region P, respectively.

Referring to FIG. 2B, first sidewall insulating layers 206 are formed on the surfaces of the first and second trenches T1 and T2, respectively. The first sidewall insulating film 206 is formed of, for example, an oxide film, and the oxide film is preferably formed through an oxidation process.

Referring to FIG. 2C, a mask pattern 208 exposing the cell region C is formed on the semiconductor substrate 200 on which the first sidewall insulating layer 206 is formed. The mask pattern 208 is formed of, for example, a nitride film or a photosensitive film. Then, the first sidewall insulating film 206 of the exposed cell region C is selectively removed.

Referring to FIG. 2D, after removing the mask pattern, the second sidewall insulating layer 210 is formed on the surface of the first sidewall insulating layer 206 of the ferry region P and the first trench T1 of the cell region C. ). The second sidewall insulating film 210 is formed of, for example, an oxide film, and the oxide film is preferably formed through an oxidation process.

As a result, a second sidewall insulating film 210 is formed on the surface of the first trench T1 of the cell region C, and first and second sidewalls are formed on the surface of the second trench T2 of the ferry region P. Insulating films 206 and 210 are formed. Therefore, the present invention can form a sidewall insulating film having a thicker thickness in the ferry region P than the cell region C, preferably 5 to 200 Å thicker. (W1 <W2)

On the other hand, it is also possible to form a liner insulating film (not shown) on the second sidewall insulating film 210, the liner insulating film, for example, is formed in a structure including at least one of a nitride film and an oxide film.

Referring to FIG. 2E, an insulating film 212 is formed on the semiconductor substrate 200 on which the second sidewall insulating film 210 is formed so as to fill the first and second trenches T1 and T2. The insulating film 212 is subjected to chemical mechanical polishing (CMP) until it is exposed. Then, the exposed pad nitride film and the pad oxide film under it are removed.

Subsequently, although not shown, a series of subsequent known processes are sequentially performed to complete the formation of the device isolation film of the semiconductor device according to the first embodiment of the present invention.

As described above, in the first embodiment of the present invention, after selectively removing the first sidewall insulating film of the cell region, a second sidewall insulating film is formed in the cell region and the ferry region, thereby providing a second sidewall insulating film in the cell region, In addition, first and second sidewall insulating films may be formed in the ferry area, and thus, sidewall insulating films having a thicker thickness may be formed in the ferry area than in the cell area.

Therefore, the present invention can improve the gap-fill characteristics in the cell region and also improve the hot-carrier characteristics in the ferry region.

3A to 3E are cross-sectional views illustrating processes of forming a device isolation film of a semiconductor device according to a second exemplary embodiment of the present invention.

Referring to FIG. 3A, a pad oxide layer 302 and a pad nitride layer 304 are sequentially formed on the semiconductor substrate 300 including the cell region C and the ferry region P. Referring to FIG. The pad nitride layer 304 and the pad oxide layer 302 are etched to expose the portion of the semiconductor substrate 300, and then the exposed portion of the semiconductor substrate 300 is etched to expose the cell region C of the semiconductor substrate 300, and First and second trenches T1 and T2 are formed in the ferry region P, respectively.

Referring to FIG. 3B, first sidewall insulating layers 306 are formed on the surfaces of the first and second trenches T1 and T2, respectively. The first sidewall insulating film 306 is formed of, for example, an oxide film, and the oxide film is preferably formed through an oxidation process.

Referring to FIG. 3C, a mask pattern 308 exposing the ferry region P is formed on the semiconductor substrate 300 on which the first sidewall insulating layer 306 is formed. The mask pattern 308 is formed of, for example, a nitride film or a photosensitive film. Then, a second sidewall insulating film 310 is selectively formed on the first sidewall insulating film 306 of the exposed ferry region P. The second sidewall insulating layer 310 is formed of, for example, an oxide film, and the oxide film is preferably formed through an oxidation process.

Referring to FIG. 3D, the mask pattern is removed. As a result, a first sidewall insulating layer 306 is formed on the surface of the first trench T1 of the cell region C, and first and second surfaces on the surface of the second trench T2 of the ferry region P. Sidewall insulating films 306 and 310 are formed. Therefore, the present invention can form a sidewall insulating film having a thicker thickness in the ferry region P than the cell region C, preferably 5 to 200 Å thicker. (W1 <W2)

Meanwhile, a liner insulating film (not shown) may be formed on the first and second sidewall insulating films 306 and 310, and the liner insulating film may be formed of a structure including at least one of a nitride film and an oxide film, for example. .

Referring to FIG. 3E, an insulating layer 312 is formed to fill the first and second trenches T1 and T2 on the semiconductor substrate 300 on which the first and second sidewall insulating layers 306 and 310 are formed. Next, the insulating film 312 is CMP until the pad nitride film is exposed. Then, the exposed pad nitride film and the pad oxide film under it are removed.

Subsequently, although not shown, a series of subsequent known processes are sequentially performed to complete the formation of the device isolation film of the semiconductor device according to the second embodiment of the present invention.

As described above, in the second embodiment of the present invention, by selectively forming a second sidewall insulating film on the first sidewall insulating film of the ferry region, a first sidewall insulating film is formed in the cell region, and a first sidewall insulating film is formed in the ferry region. And a second sidewall insulating film, whereby a sidewall insulating film having a thicker thickness in the ferry region than in the cell region can be formed.

Therefore, the present invention can improve the gap-fill characteristics in the cell region and also improve the hot-carrier characteristics in the ferry region.

4A through 4D are cross-sectional views illustrating processes of forming an isolation layer of a semiconductor device in accordance with a third embodiment of the present invention.

Referring to FIG. 4A, a pad oxide film 402 and a pad nitride film 404 are sequentially formed on a semiconductor substrate 400 including a cell region C and a ferry region P. Referring to FIG. The pad nitride layer 404 and the pad oxide layer 402 are etched to expose a portion of the semiconductor substrate 400, and then the exposed portion of the semiconductor substrate 400 is etched to expose the cell region C of the semiconductor substrate 400, and First and second trenches T1 and T2 are formed in the ferry region P, respectively.

Referring to FIG. 4B, a mask pattern 406 exposing the ferry region P is formed on the semiconductor substrate 400 on which the first and second trenches T1 and T2 are formed. The mask pattern 406 is formed of, for example, a nitride film or a photosensitive film. Subsequently, an oxygen ion implantation process is performed on the exposed ferry region P.

Referring to FIG. 4C, the mask pattern is removed from the resultant of the semiconductor substrate 400 in which the oxygen ion implantation process is performed. Then, an oxidation process is performed on the semiconductor substrate 400 from which the mask pattern has been removed, so that first and second trenches T1 and T2 of the cell region C and the ferry region P are respectively formed on the surfaces of the semiconductor substrate 400. And second sidewall oxide films 408 and 410.

Here, the second sidewall oxide film 410 of the ferry region P in which the oxygen ion implantation process is performed is thicker than the first sidewall oxide film 408 of the cell region C in which the oxygen ion implantation process is not performed. Preferably, it is 5 to 200 mm thicker. (W1 <W2)

Meanwhile, it is also possible to form a liner insulating film (not shown) on the first and second sidewall oxide films 408 and 410, and the liner insulating film has a structure including, for example, at least one of a nitride film and an oxide film. do.

Referring to FIG. 4D, an insulating film 412 is formed to fill the first and second trenches T1 and T2 on the semiconductor substrate 400 on which the first and second sidewall oxide films 408 and 410 are formed. Next, the insulating film 412 is CMP until the pad nitride film is exposed. Then, the exposed pad nitride film and the pad oxide film under it are removed.

Subsequently, although not shown, a series of subsequent known processes are sequentially performed to complete the formation of the device isolation film of the semiconductor device according to the third embodiment of the present invention.

As described above, in the third embodiment of the present invention, the oxygen ion implantation process is performed in the ferry region where the oxygen ion implantation process is performed by performing an oxidation process after selectively performing an oxygen ion implantation process in the ferry region. It is possible to form a sidewall oxide film having a thicker thickness than in an uncelled cell region.

Therefore, the present invention can improve the gap-fill characteristics in the cell region and also improve the hot-carrier characteristics in the ferry region.

5A through 4D are cross-sectional views illustrating processes of forming an isolation layer of a semiconductor device in accordance with a fourth embodiment of the present invention.

Referring to FIG. 5A, a pad oxide film 502 and a pad nitride film 504 are sequentially formed on a semiconductor substrate 500 including a cell region C and a ferry region P. Referring to FIG. The pad nitride layer 504 and the pad oxide layer 502 are etched to expose portions of the semiconductor substrate 500, and then the exposed portions of the semiconductor substrate 500 are etched to expose the cell regions C of the semiconductor substrate 500. And first and second trenches T1 and T2 in the ferry region P, respectively.

Referring to FIG. 5B, a mask pattern 506 exposing the cell region C is formed on the semiconductor substrate 500 on which the first and second trenches T1 and T2 are formed. The mask pattern 506 is formed of, for example, a nitride film or a photosensitive film. Subsequently, a nitrogen ion implantation process is performed on the exposed cell region P.

Referring to FIG. 5C, the mask pattern is removed from the result of the semiconductor substrate 500 in which the nitrogen ion implantation process is performed. Then, an oxidation process is performed on the semiconductor substrate 500 from which the mask pattern has been removed, so that first and second trenches T1 and T2 are respectively formed on the surface of the cell region C and the ferry region P, respectively. And second sidewall oxide films 508 and 510.

Here, the first sidewall oxide film 508 of the cell region C in which the nitrogen ion implantation process is performed is thinner than the second sidewall oxide film 510 of the ferry region C in which the nitrogen ion implantation process is not performed. Preferably, it has a thickness of 5 to 200 mm thinner. (W1 <W2)

Meanwhile, it is also possible to form a liner insulating film (not shown) on the first and second sidewall oxide films 508 and 410, and the liner insulating film has a structure including at least one of, for example, a nitride film and an oxide film. .

Referring to FIG. 5D, an insulating film 512 is formed to fill the first and second trenches T1 and T2 on the semiconductor substrate 500 on which the first and second sidewall oxide films 508 and 510 are formed. Next, the insulating film 512 is CMP until the pad nitride film is exposed. Then, the exposed pad nitride film and the pad oxide film under it are removed.

Subsequently, although not shown, a series of subsequent known processes are sequentially performed to complete the formation of the device isolation film of the semiconductor device according to the fourth embodiment of the present invention.

As described above, in the fourth embodiment of the present invention, the nitrogen ion implantation process is performed in the cell region in which the nitrogen ion implantation process is performed by performing the oxidation process after selectively performing the nitrogen ion implantation process in the cell region. It is possible to form a sidewall oxide film having a thinner thickness than in the ferry area.

Therefore, the present invention can improve the gap-fill characteristics in the cell region and also improve the hot-carrier characteristics in the ferry region.

As mentioned above, although the present invention has been illustrated and described with reference to specific embodiments, the present invention is not limited thereto, and the following claims are not limited to the scope of the present invention without departing from the spirit and scope of the present invention. It can be easily understood by those skilled in the art that can be modified and modified.

1 is a cross-sectional view illustrating a device isolation film of a semiconductor device in accordance with an embodiment of the present invention.

2A to 2E are cross-sectional views illustrating processes of forming a device isolation film of a semiconductor device in accordance with a first embodiment of the present invention.

3A to 3E are cross-sectional views illustrating processes of forming a device isolation film of a semiconductor device in accordance with a second embodiment of the present invention.

4A to 4D are cross-sectional views illustrating processes of forming a device isolation film of a semiconductor device in accordance with a third embodiment of the present invention.

5A through 5D are cross-sectional views illustrating processes of forming an isolation layer of a semiconductor device in accordance with a fourth embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

C: cell area P: ferry area

100 semiconductor substrate 102 pad oxide film

104: pad nitride film T1: first trench

T2: second trench 108: first sidewall insulating film

110: second sidewall insulating film 112: insulating film

Claims (11)

A semiconductor substrate provided with a trench; A sidewall insulating film formed on a surface of the trench; And An insulating film formed on the sidewall oxide film to fill the trench; And the sidewall oxide layer has a thicker thickness in the ferry region than in the cell region. The method of claim 1, And the sidewall insulating film is formed of an oxide film. The method of claim 1, And the sidewall insulating layer has a thickness of 5 to 200 Å thicker in the ferry region than in the cell region. Etching the semiconductor substrate including the cell region and the ferry region to form trenches in each of the regions; Forming a sidewall insulating film having a thicker thickness in the ferry region than on the cell region on the surface of the trench; And Forming an insulating film to fill the trench on the sidewall insulating film; Device isolation film forming method of a semiconductor device comprising a. The method of claim 4, wherein And the sidewall insulating film is formed of an oxide film. The method of claim 4, wherein And the sidewall insulating film is formed to have a thickness of 5 to 200 Å thicker in the ferry region than in the cell region. The method of claim 4, wherein Forming the sidewall insulating film, Forming a first sidewall insulating film on a surface of the trench; Forming a mask pattern exposing a cell region on the semiconductor substrate on which the first sidewall insulating film is formed; Removing a first sidewall insulating film of the exposed cell area; Removing the mask pattern; And Forming a second sidewall insulating film on the first sidewall insulating film of the ferry region and a trench surface of the cell region; Device isolation film forming method of a semiconductor device comprising a. The method of claim 4, wherein Forming the sidewall insulating film, Forming a first sidewall insulating film on a surface of the trench; Forming a mask pattern exposing a ferry region on the semiconductor substrate on which the first sidewall insulating film is formed; Forming a second sidewall insulating film on the first sidewall insulating film of the exposed ferry region; And Removing the mask pattern; Device isolation film forming method of a semiconductor device comprising a. The method of claim 4, wherein Forming the sidewall insulating film, Forming a mask pattern exposing a ferry region on the trench formed semiconductor substrate; Performing oxygen ion implantation into the exposed ferry area; Removing the mask pattern; And Performing an oxidation process on the semiconductor substrate from which the mask pattern is removed; Device isolation film forming method of a semiconductor device comprising a. The method of claim 4, wherein Forming the sidewall insulating film, Forming a mask pattern exposing a cell region on the trench formed semiconductor substrate; Performing nitrogen ion implantation into the exposed cell region; Removing the mask pattern; And Performing an oxidation process on the semiconductor substrate from which the mask pattern is removed; Device isolation film forming method of a semiconductor device comprising a. The method according to any one of claims 7 to 10, And the mask pattern is formed of a nitride film or a photoresist film.

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