KR100256818B1 - Method of forming device isolation film of semiconductor device - Google Patents

Abstract

The present invention relates to a method of forming a device isolation film of a semiconductor device, wherein a first insulating film is formed on a semiconductor substrate by a thermal oxidation process, a nitride film is formed on the entire surface by a chemical vapor deposition method, and then a trench is formed. After the thermal oxide film is grown by the primary oxidation process, the thermal oxide film is removed by a wet etching method, and then the thermal oxide film is grown on the trench surface by the secondary oxidation process, and then the inner wall of the chamber is formed by the oxide film or the PECVD equipment. a nitride film pre-coating (pre-coating) with the - situ cleaning (in-situ cleaning) directly by the plasma treatment to prevent metal contamination, ozone Teos oil to fill the trench without S if (O _3. - TEOS USG: O ₃ - a TetraEthylOrthoSilicate UndopedSilicateGlass, also O ₃ -TEOS USG la below) were vapor-deposited film is planarized by chemical mechanical polishing (referred to as chemical mechanical polishing, hereinafter CMP) process agent To form a tooth isolation film by facilitating the subsequent process is to increase the yield of the semiconductor device and technique that enables high integration thereof.

Description

Method of forming device isolation film of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a device isolation film of a semiconductor device, and in particular, in a device separation process using plasma enhanced chemical vapor deposition (PECVD) equipment, to prevent contamination of a wafer by a PECVD chamber. The present invention relates to a technique for improving yield and reliability of semiconductor devices.

A method of forming a device isolation film of a general semiconductor device is as follows.

First, a pad oxide film, which is a first insulating film, is formed on the semiconductor substrate by a thermal oxidation process to a thickness of 100 to 200Å, and a nitride film, which is a second insulating film, is deposited on the entire surface by chemical vapor deposition (CVD). Is deposited to a thickness of 1500-2500 mm 3.

Next, a trench is formed by etching the second insulating film, the first insulating film, and a semiconductor substrate having a predetermined thickness by an etching process using an element isolation mask.

A third insulating film is formed on the surface of the trench, and a plasma treatment is performed on the entire surface of the trench in nitrogen and ammonia gas. Then, an O ₃ -TEOS USG film is formed on the entire surface to be planarized.

In this case, the trench surface may be contaminated due to the metal material included in the inner wall of the reaction chamber during the plasma treatment process.

As described above, in the method of forming a device isolation film of a semiconductor device according to the prior art, metal contamination is induced on the surface of a semiconductor substrate by a chamber during a plasma processing process, thereby deteriorating device characteristics and deteriorating characteristics and reliability of the device. There is a problem.

In order to solve the above problems of the prior art, before the plasma treatment in the PECVD chamber, the chamber inner wall is coated with an oxide film or a nitride film, and plasma treatment is performed without in-situ cleaning to remove metal contamination caused by the inner wall of the chamber. The present invention provides a method of forming a device isolation film of a semiconductor device which can minimize the occurrence and improve the self-planarization characteristics by controlling the deposition rate of O ₃ -TEOS USG by performing the plasma treatment process and easily perform the subsequent process. There is this.

1A to 1E are cross-sectional views illustrating a method of forming an isolation layer in a semiconductor device according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

11: semiconductor substrate 13: first insulating film

15: second insulating film 16: trench

17: fourth insulating film 19: O ₃ -TEOS USG film

Device isolation film forming method of a semiconductor device according to the present invention for achieving the above object,

Forming a first insulating film on the semiconductor substrate;

Forming a second insulating film on the first insulating film;

Forming a trench by etching the second insulating film, the first insulating film, and a semiconductor substrate having a predetermined thickness;

Forming a third insulating film on the trench surface;

Removing the third insulating film;

Forming a fourth insulating film on the trench surface;

Forming a fifth insulating film on an inner wall of the chamber in which the semiconductor substrate is embedded;

Performing a N ₂ / NH ₃ plasma treatment on the fourth insulating film;

And filling the trench with O ₃ -TEOS USG.

On the other hand, the principle of the present invention for achieving the above object is, in performing a shallow trench isolation process, by pre-coating the inner wall of the PECVD chamber which is a reaction chamber with an oxide film or a nitride film before performing the plasma treatment process After minimizing the possibility of metal contamination and performing the plasma treatment process, O ₃ -TEOS USG is deposited on the trench to rapidly deposit O ₃ -TEOS USG on the oxide layer and O3-TEO USG on the nitride layer to slow down the deposition. It improves the characteristics and improves the process uniformity and productivity by reducing the process time of the subsequent CMP process.

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

1A to 1E are cross-sectional views illustrating a process of forming an isolation layer in a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 1A, a pad oxide film, which is the first insulating layer 13, is formed on the semiconductor substrate 11. At this time, the pad oxide film 13 is formed by a thermal oxidation process, but is formed to a thickness of about 50 to 200Å.

A nitride film, which is the second insulating film 15, is formed on the first insulating film 13 to have a predetermined thickness. In this case, the nitride film 15 is formed to a thickness of about 1500 to 2500Å by chemical vapor deposition.

Next, a trench 16 is formed in the cell portion and the peripheral circuit portion of the semiconductor substrate 11 by an etching process using an element isolation mask (not shown).

Referring to FIG. 1B, a first oxidation process is performed to form a first thermal oxide film (not shown), which is a third insulating film, on the surface of the trench 16. In this case, the first thermal oxide film is formed to a thickness of about 100 ~ 200Å.

Then, the first thermal oxide film is removed by wet etching.

In this case, the first oxidation process and the first thermal oxide film removal process remove defects on the surface of the trench 16 generated during the trench 16 formation process.

Referring to FIG. 1C, a second thermal oxide film, which is the fourth insulating film 17, is formed on the surface of the trench 16 to a thickness of about 100 to about 200 kPa by the second oxidation process.

Referring to FIG. 1D, after the second thermal oxidation process, the inner wall of the chamber is pre-coated to an thickness of 5 to 10 μm of an oxide film, a nitride film, or an oxynitride film as an insulating film (not shown).

In this case, the pre-coating process may be performed without an in-situ cleaning process when one kind of deposition material proceeds in PECVD and another deposition material proceeds in a subsequent process.

Subsequently, the underlying dependence of the O ₃ -TEOS USG is reduced by plasma treating the surface of the wafer (not shown) in a chamber (not shown) with an insulating film precoated on the inner wall.

At this time, the plasma treatment step is N ₂ / NH ₃ = 1 to 3/2 to 10 LSM, HF / LF = 0.1 to 1.0 / 0.1 to 0.3 which is weaker than the conditions when depositing O ₃ -TEOS USG It is carried out for a time of 10 to 50 seconds under conditions having a power of kW, a temperature of 300 to 400 DEG C and a pressure of 1.0 to 2.0 Torr.

Here, according to the experimental results of the present inventors, the amount of metal contaminants present on the surface of the trench 16 during the pre-coating and the plasma treatment is reduced to about 1/10 of the case without the pre-coating. do.

In addition, when the O ₃ -TEOS USG film filling the trench 16 is deposited by the plasma treatment process, the deposition time is faster in the thermal oxide film and the deposition time is slower on the nitride film, thereby improving the self-planarization property, thereby improving the process time of the subsequent CMP process. Minimize the number to facilitate the planarized trench isolation process.

Referring to FIG. 1E, after the plasma treatment process, the O ₃ -TEOS USG 19 is deposited on the entire surface to fill the trench 16 with the O ₃ TEOS USG 19.

At this time, the deposition process of the O ₃ TEOS USG 19 is formed in a thickness of about 5000 to 7000 Pa at a flow rate of nitrogen gas of about 80 to 120 SLM and an ozone concentration of about 100 to 140 g / m 3.

Subsequently, although not shown, subsequent heat treatment and a CMP process are performed to complete the shallow trench isolation process.

As described above, the method of forming a device isolation film of a semiconductor device according to the present invention minimizes metal contamination caused by a plasma treatment process by pre-coating a chamber inner wall with an oxide film or a nitride film, and improves the self-planarization characteristics of O ₃ TEOS USG. By reducing the process time of the CMP process, and facilitates the subsequent process to improve the characteristics, yield, and productivity of the semiconductor device, and thereby the high integration of the semiconductor device is possible.

Claims (8)

Forming a first insulating film and a second insulating film on the semiconductor substrate; forming a trench by etching the second insulating film, the first insulating film, and a semiconductor substrate having a predetermined thickness using an isolation mask; and forming a trench surface. in the step of removing after the formation of the thermal oxide film, a step of forming a thermal oxide film on the trench surface, and forming an insulating film on the inner wall of the semiconductor substrate with the chamber, the surface of the semiconductor substrate N ₂ / A method of forming an isolation film in a semiconductor device, the method comprising: treating with NH ₃ plasma; and filling the trench with O ₃ TEOS USG. The method of claim 1, wherein the first insulating film is a pad oxide film having a thickness of 50 to 200 kHz. The method of claim 1, wherein the second insulating film is a nitride film having a thickness of 1500 to 2500 Å. The method of claim 1, wherein the thermal oxide layers are formed to a thickness of about 100 to about 200 microns. The method of claim 1, wherein the insulating film formed on the inner wall of the chamber is formed of one of an oxide film, a nitride film, and an oxynitride film. The method of claim 1 or 5, wherein the insulating film formed on the inner wall of the chamber is formed to a thickness of 5 ~ 10㎛. The method of claim 1, wherein the plasma treatment process is N ₂ / NH ₃ flow rate of 1 to 2/2 to 10 SLM, HF / LF power of 0.1 to 1.0 / 0.1 to 0.3 kW, 300 to 400 ℃ temperature, 1.0 to 2.0 Torr A device isolation film forming method for a semiconductor device, characterized in that carried out for a time of 10 to 50 seconds at a pressure of. The semiconductor device according to claim 1, wherein the O ₃ -TEOS USG is formed at a thickness of 5000 to 7000 Pa at a nitrogen flow rate of 80 to 120 SLM, an ozone concentration of 100 to 140 g / m 3, and a temperature of 350 to 450 ° C. 3. Device isolation film formation method of.

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