KR100190364B1 - Method of forming an element isolation film in a semiconductor device - Google Patents

Abstract

The present invention comprises the steps of forming an anti-oxidation film on a semiconductor substrate; Selectively etching a predetermined depth of the antioxidant layer and the semiconductor substrate using a device isolation mask; Forming an insulating film on the entire structure by chemical vapor deposition (CVD); Coating a photosensitive film on the insulating film; A method of forming a semiconductor device isolation film comprising a step of etching back the photoresist and the insulating film until the antioxidant film is exposed, and removing the antioxidant film, wherein the feed region is formed in a trench structure, The field oxide film, which is an insulating film between devices, is formed by the CVD method to minimize the buzz bee phenomenon generated during the thermal oxidation process and the step difference between the field region and the active region. Effect is suppressed.

Description

Method of forming semiconductor device separator

1a and 1b is a cross-sectional view of the device isolation film forming process according to the prior art,

2A to 2D are cross-sectional views of a device isolation film forming process according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1, 10: silicon substrate 2, 20: pad oxide film

3, 30: nitride film 4, 40: active region

5, 50: field area 60: CVD oxide film

70: first photosensitive film 80: second photosensitive film

9: field oxide film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device isolation method of a semiconductor device, and in particular, a semiconductor which minimizes a step between the active area and the field area and a bird's beak phenomenon caused by the end of the oxidation mask being raised upward during the thermal oxidation process. A device isolation film formation method of a device is provided.

In general, the device isolation film electrically and structurally separates individual devices constituting the integrated device from each other so that each device can perform a given function independently without interference from adjacent devices.

1A and 1B illustrate a process of forming a semiconductor device isolation film by a conventional method, and illustrate a LOCOS (LOCal Oxidation of Silicon) process.

First, as shown in FIG. 1A, a pad oxide film 2 on the silicon substrate 1 and a nitride film 3 on the order of 1000 to 2000 microseconds are sequentially formed on the silicon substrate 1, and then the device overlaps with the active region 4. The nitride film 3 is removed using a separation mask until the pad oxide film 2 is exposed.

Subsequently, as shown in FIG. 1B, a field oxide film 9, which is an inter-element insulating film, is formed through the thermal oxidation process.

At this time, as the sidewalls of the nitride film 3 are raised, a field oxide film 9 is formed to generate a bird's beak (A), thereby reducing the active region 4 and reducing the active region 4. Steps (B, B) are generated between the field regions 5, so that a necking phenomenon or a loading effect occurs during the subsequent metal wiring process.

Disclosure of Invention The present invention devised to solve the above problems is to provide a method for forming a semiconductor device isolation layer which minimizes generation of a buzz beak and a step difference between an active region and a field region.

In order to achieve the above object, the present invention provides a method for forming a semiconductor device isolation film, the method comprising: forming an oxide film on a semiconductor substrate, selectively etching a predetermined depth of the antioxidant film and the semiconductor substrate using an element isolation mask; Forming an insulating film on the entire structure by a chemical vapor deposition (CVD) method, applying a photosensitive film on the insulating film, etching back the photosensitive film and the insulating film until the antioxidant film is exposed, and removing the antioxidant film. Characterized in that it comprises a step.

Hereinafter, the present invention will be described in detail with reference to FIGS. 2A through 2D.

2A through 2D are diagrams illustrating a process of manufacturing a semiconductor small-gauge separator according to an exemplary embodiment of the present invention.

First, as shown in FIG. 2A, a 200 nm to 300 nm pad oxide film 20 and a 1000 nm to 1500 nm nitride film 30 are sequentially formed on the silicon substrate 10, and then overlapped with the active region 40. The first photosensitive film 70 is formed.

Subsequently, as shown in FIG. 2B, the nitride film 30, the pad oxide film 20, and the over-etch angle by the SF ₆ + He plasma having a low etching selectivity using the first photoresist film 70 as an etch field wall film. A trench structure is formed by removing a silicon substrate having a thickness of 200 kHz to 300 kHz, and then the first photoresist layer 70 is removed.

Subsequently, as shown in FIG. 2C, the CVD oxide film 60 is deposited by CVD (Chemical Vapor Deposition) method on the entire structure, and then the CVD oxide film ( 60) a second photosensitive film 80 is formed on the upper portion.

Lastly, as shown in FIG. 2D, when the nitride layer 30 is exposed by using CF ₄ + O ₂ plasma having a selective etching ratio of the second photoresist layer 80 and the CVD oxide layer 60 as low as about 1: 1.5. The second photoresist film 80 and the CVD oxide film 60 are etched back until then, and the nitride film 30 is removed to form a field oxide film as an inter-element insulating film with the remaining CVD oxide film 60a.

Reference numeral 50 denotes a field area.

According to the present invention as described above, the field region is formed in a trench structure, and the field oxide film, which is an inter-element insulating film, is formed by CVD, thereby minimizing the buzz bee phenomenon generated during the thermal oxidation process and the step difference between the field region and the active region. It has the effect of suppressing the necking phenomenon or loading effect which is likely to occur during the subsequent metallization process.

The method for forming a semiconductor device isolation film according to the present invention described above is not limited by the claims and the accompanying drawings, and the general knowledge in the technical field to which the present invention belongs without departing from the spirit of the present invention. Various substitutions, modifications, and alterations that may be made by those having the same are also within the scope of the present invention.

Claims (9)

A semiconductor device, comprising: forming an anti-oxidation film on a semiconductor substrate, selectively etching a predetermined depth of the anti-oxidation film and the semiconductor substrate using a device isolation mask, and chemical vapor deposition (CVD) over the entire structure Forming an insulating film, applying a photosensitive film on the insulating film, and etching back the photosensitive film and the insulating film until the anti-oxidation film is exposed, and removing the anti-oxidation film. Device isolation film formation method. The method of claim 1, wherein the anti-oxidation film is a film in which a pad oxide film and a nitride film are sequentially stacked. The method of claim 2, wherein the nitride film is formed to have a thickness of 1000 Å to 1500 Å. The method of claim 2, wherein the pad oxide layer is formed to have a thickness of about 200 kV to about 300 kPa. The method of claim 2, wherein the selective etching of the antioxidant layer and the semiconductor substrate is performed by SF ₆ + He plasma having a low etching selectivity. 3. The method of claim 2, wherein the semiconductor substrate is removed by about 200 kV to about 300 kV during selective etching of the antioxidant film and the semiconductor substrate. And the insulating film is a CVD (chemical vapor deposition) oxide film. The method of claim 7, wherein the oxide film is formed to a thickness of 4500 kV to 5500 kV in a manner. 10. The method of claim 8, wherein the etch back of the photosensitive film and the oxide film is formed by a CF ₄ + O ₂ plasma having a selective etching ratio of the photosensitive film and the oxide film being about 1: 1.5.