KR20080114177A - Method of manufacturing a field oxide layer structure - Google Patents

Abstract

A method for manufacturing a field oxide layer structure is provided to form a first field oxide layer pattern to suppress the gap generation with the active pattern and a second field oxide pattern to generate the gap with the active pattern by masking a second region of a substrate while forming a first liner layer by removing a part of the liner layer positioned in a first region of the substrate. A first trench and a second trench are formed by etching a substrate by using a mask pattern formed on a substrate(100) as an etching mask. A first oxide layer is formed according to a profile of inner lateral surface of the first and second trenches. A liner layer with an etching selection ratio and the first oxide layer are formed according to the profile of a surface of mask patterns and inner lateral surfaces of the first and second trenches where the first oxide layer is formed. A second oxide layer reclaiming the first and second trenches is formed. A third oxide layer with an upper surface lower than the substrate is formed by etching a part of the second oxide layer. A first liner pattern(130) is formed in a part of inner lateral side of the first trench by selectively etching the exposed linear film. A fourth oxide layer is formed on the third oxide layer. A second liner layer pattern(136) is formed in a part of inner lateral side of the second trench by removing a part of the liner layer in the inner lateral side of the first trench and a mask pattern.

Description

Method of manufacturing a field oxide layer structure

1 to 10 are schematic plan views illustrating a method of forming a field oxide film structure according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100 substrate 108 first pad oxide film pattern

110: second pad oxide film pattern 112: first active pattern

114: second active pattern 120: first oxide film pattern

130: first liner film pattern 134: first field insulating film pattern

136: second liner film pattern 138: second field insulating film pattern

140: gap

The present invention relates to a method of forming a field oxide structure. More specifically, the present invention relates to a method of forming a field oxide film structure having a shallow trench structure.

Semiconductor devices are used in a variety of electronic applications, such as computers, mobile phones, digital cameras, and many other electronic equipment. Semiconductor devices are generally fabricated by sequentially depositing insulating, conductive and other material layers on a semiconductor substrate and patterning them to form circuit elements or components. Electrical components, such as transistors, capacitors, diodes, conductive lines and other components, are formed in a variety of materials connected by conductive interlayer contacts or pads for forming integrated circuits.

Field insulation regions are formed in the semiconductor device to electrically isolate adjacent electrical components or unit devices. The field insulation region is typically formed by etching a substrate to form a trench, and filling the trench with a material such as silicon oxide.

Here, before filling the trench with silicon oxide, a thermal oxide film and a liner film are sequentially formed in the trench.

In more detail, the trench is formed by forming a mask pattern on a substrate and anisotropically etching the substrate by performing a plasma process using the mask pattern as an etching mask. In this case, the inner surface of the trench is damaged by the plasma process, and a thin thermal oxide film is formed on the inner surface of the trench to heal it.

In addition, a stress is generated at the boundary between the field insulating region and the substrate according to the difference in the coefficient of thermal expansion and the volume expansion between the silicon oxide embedded in the trench and the substrate (silicon). Also, impurities of impurity regions formed in the active region may penetrate into the field insulating region. In order to overcome this, a liner layer is continuously formed along the inner surface of the trench in which the thermal oxide film is formed and the mask pattern surface. In this case, the liner layer may include substantially the same material as the mask pattern, for example, silicon nitride.

Subsequently, after forming a field insulating film containing silicon oxide on the mask pattern to fill the trench in which the thermal oxide film and the liner film are formed, the top of the field insulating film is planarized to expose the top surface of the mask pattern. Subsequently, in removing the mask pattern, the liner film includes substantially the same material as the mask pattern, so that a part of the liner film adjacent to the substrate surface is removed.

As a result, a portion of the liner film is removed to form a gap between the active region and the field insulation region. As described above, some semiconductor devices require a field insulating film pattern structure in which a gap is generated.

On the other hand, there is a demand for a semiconductor device that requires a field insulating film pattern structure in which the generation of the gap is suppressed, and thus a process for forming a field insulating film pattern structure in which the gap is formed and a field insulating film pattern structure in which gap generation is suppressed is required. It is becoming.

An object of the present invention for solving the above problems is to provide a method of forming a field oxide film structure having a structure in which a gap is formed between an active pattern and a field pattern, and a structure in which gap generation is suppressed.

According to an aspect of the present invention for achieving the above object, in the method for forming a field oxide film structure, using the mask pattern formed on the substrate as an etching mask to etch the substrate to form a first trench and a second trench . A first oxide layer is formed along the profiles of the inner surfaces of the first trench and the second trench. A liner layer having an etch selectivity with respect to the first oxide layer is formed along the profile of the first and second trench inner surfaces and the mask patterns on which the first oxide layer is formed. A second oxide film is formed to fill the first trench and the second trench. A portion of the upper portion of the second oxide layer filling the first trench is etched to form a third oxide layer having a lower upper surface than the substrate. The liner layer exposed by the third oxide layer is selectively etched to form a first liner layer pattern on a portion of the inner side of the first trench. A fourth oxide film is formed on the third oxide film. A portion of the liner layer on the inner side of the first trench and the mask pattern is removed to form a second liner layer on the inner side of the second trench.

According to an embodiment of the present invention, the method of forming the field oxide film structure may further include forming a pad oxide film on the substrate before forming the mask pattern.

According to another embodiment of the present invention, the liner layer may include nitride.

According to another embodiment of the present invention, the first oxide film may be formed by an oxidation process.

According to another embodiment of the present invention, the first oxide layer may extend along the surface of the mask pattern.

According to another embodiment of the present invention, the first oxide film may be formed by a plasma oxidation or deposition process.

According to another embodiment of the present invention, the second oxide film may be formed by a deposition process or a spin coating process.

According to another embodiment of the present invention, in the method of forming the field oxide film structure, before the removing of the mask pattern, a second oxide film to fill the first trench, and a fourth to fill the second trench The method may further include etching the upper portion of the oxide layer to expose the liner layer portion on the mask pattern.

 The second oxide film forms a preliminary second oxide film that completely fills the first trench and the second trench, and selectively exposes a preliminary second oxide film that fills the first trench on the preliminary second oxide film. The second mask pattern may be formed, and may be formed by selectively etching the exposed preliminary second oxide layer using the second mask pattern as an etching mask.

According to the present invention, by masking the liner layer formed inside the second trench while the first liner layer pattern is formed in the first trench, the field oxide film structure formed thereafter has a structure in which an active pattern and a gap are formed; It may include any structure in which generation of gaps is suppressed. Thereby, the formation of the field oxide film structure having various structures can be performed more easily.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments, and those skilled in the art will appreciate the technical spirit of the present invention. The present invention may be embodied in various other forms without departing from the scope of the present invention. In the accompanying drawings, the dimensions of the substrate, film, region, pad or patterns are shown to be larger than the actual for clarity of the invention. In the present invention, when each film, region, pad or pattern is referred to as being formed "on", "upper" or "top surface" of a substrate, each film, region or pad, each film, region, Meaning that the pad or patterns are formed directly on the substrate, each film, region, pad or patterns, or another film, another region, another pad or other patterns may be additionally formed on the substrate. In addition, where each film, region, pad, region or pattern is referred to as "first," "second," "third," and / or "preliminary," it is not intended to limit these members, but only the cornea, To distinguish between areas, pads, regions or patterns. Thus, "first", "second", "third" and / or "preparation" may be used selectively or interchangeably for each film, region, pad, site or pattern, respectively.

Hereinafter, a method of forming a field oxide film structure according to an embodiment of the present invention will be described in detail.

1 to 12 are schematic cross-sectional views illustrating a method of forming a field oxide film structure according to an embodiment of the present invention.

Referring to FIG. 1, a pad oxide film 102 is formed on a substrate 100.

The substrate 100 may be a semiconductor substrate including silicon or germanium or a silicon on isolation (SOI) substrate. The substrate 100 includes a first region and a second region, and first trenches are formed in the first region, and second trenches are formed in the second region, respectively.

The pad oxide layer 102 is formed on the substrate 100 by a thermal oxidation or chemical vapor deposition process. The pad oxide layer 102 may function as a layer for alleviating stress between the first mask patterns formed thereafter and the substrate 100.

Referring to FIG. 2, first mask patterns 104 and second mask patterns 106 are formed on the pad oxide layer 102.

The first mask patterns 104 are provided on the first area of the substrate 100, and the second mask patterns 106 are provided on the second area of the substrate 100.

A process of forming the first mask patterns 104 and the second mask patterns 106 will be described in detail. First, a mask film (not shown) is formed on the pad oxide layer 102. The mask layer may include a nitride, for example, silicon nitride. The mask layer may be formed by a chemical vapor deposition process or the like.

Subsequently, photoresist patterns (not shown) are formed on the mask layer. Although not shown, an amorphous carbon layer (ACL) and an anti-reflection layer (ALL), not shown, are formed on the mask layer prior to forming the photoresist patterns. ) May be further formed sequentially. The amorphous carbon film and the organic antireflective film are provided to prevent the photoresist patterns sidewall profile from being poor due to diffuse reflection in a subsequent photographic process. In particular, the organic antireflection film may be a silicon oxynitride film (SiON), and may be removed while the photoresist patterns are removed.

The mask layer is etched using the photoresist patterns as an etch mask to form first mask patterns 104 in the first region of the substrate 100 and second mask patterns 106 in the second region of the substrate 100. ) Respectively.

After forming the first mask patterns 104 and the second mask patterns 106, the photoresist patterns are removed by an ashing and strip process.

Referring to FIG. 3, the pad oxide layer 102 and the substrate 100 are sequentially etched using the first mask patterns 104 and the second mask patterns 106 as etch masks to form the substrate 100. First pad oxide layer patterns 108 and first trenches 116 in a first region of the substrate, and second pad oxide layer patterns 110 and second trenches 118 in a second region of the substrate 100. ) Respectively.

Here, first active patterns 112 defined by the first trenches 116 are formed in a first region of the substrate 100, and the second region is formed in a second region of the substrate 100. Second active patterns 114 defined by trenches 118 are created. That is, portions masked by the first mask patterns 104 become first active patterns 112, and portions masked by the second mask patterns 106 are second active patterns 114. )

As the etching process, conventional plasma dry etching is used. During the plasma dry etching process, inner walls of the first trenches 116 and the second trenches 118 are damaged by the plasma.

Referring to FIG. 4, a surface of inner surfaces of the first trenches 116 and the second trenches 118 to heal the inner wall of the damaged first trenches 116 and the second trenches 118. The first oxide film 120 is continuously formed along a profile.

The first oxide film 120 may be formed by an oxidation process, a deposition process, or a plasma process.

When the first oxide film 120 is formed by an oxidation process, the first oxide film 120 is selectively formed only on inner surfaces of the first trenches 116 and the second trenches 118. Examples of the oxidation process may be thermal oxidation or in-situ steam generation (ISSG).

When the first oxide layer 120 is formed by a deposition process, the first oxide layer 120 may have the first mask patterns as well as inner surfaces of the first trenches 116 and the second trenches 118. It is continuously formed along the profile of the surfaces of 104 and second mask patterns 106. Examples of the deposition process may include a chemical vapor deposition process and the like.

When the first oxide layer 120 is formed by a plasma process, the first oxide layer 120 may have not only inner surfaces of the first trenches 116 and the second trenches 118, but the first mask pattern. Are formed continuously along the profile of the surfaces of the holes 104 and the second mask patterns 106.

Referring to FIG. 5, inner surfaces of the first trenches 116 and the second trenches 118 on which the first oxide layer 120 is formed, the first mask patterns 104 and the second mask patterns ( 106) A liner layer 122 is continuously formed along the profile of the surfaces.

The liner layer 122 may include nitride, for example, silicon nitride. The liner layer 122 may include a material substantially the same as the first mask patterns 104 and the second mask patterns 106.

The liner layer 122 subsequently reduces the stress of the field oxide layer filling the inside of the first trenches 116 and the second trenches 118, and allows impurity ions to penetrate into the field oxide layer from the formed impurity region. It is a film to prevent it.

Referring to FIG. 6, the substrate 100 and the first mask patterns to fill the first trenches 116 and the second trenches 118 in which the first oxide layer 120 and the liner layer 122 are formed. A second oxide film 124 is formed on the 104 and the second mask patterns 106.

The second oxide layer 124 is undoped silicate glass (USG), boro-phospho-silicate glass (BPSG), phosphoro-silicate glass (PSG), flowable oxide (FOX), plasma enhanced deposition of tetra-ethyl ortho-silicate, tonsilazene (TOSZ), fluoride silicate glass (FSG), and the like, and the second oxide layer 124 may be formed by a deposition process or a spin coating process. .

Subsequently, an upper portion of the second oxide layer 124 is polished to expose top surfaces of the liner layer 122 formed on the first mask patterns 104 and the second mask patterns 106. The polishing process may include a chemical mechanical polishing process, an etch-back process, or a chemical mechanical polishing and etch-back mixing process.

Referring to FIG. 7, the second oxide layer 124 formed on the second region of the substrate 100 may be selectively etched to expose a portion of the upper portion of the liner layer 122 formed inside the first trenches 116. Second oxide film patterns 126 are formed.

In more detail, third mask patterns (not shown) are formed on the second oxide layer. The third mask patterns selectively expose a second oxide film formed on the first region of the substrate 100, and selectively mask the second oxide film formed on the second region of the substrate 100. The third mask patterns may be photoresist patterns.

The second oxide layer may be etched using the third mask patterns as an etch mask to expose second upper portion of the liner layer 122 formed in the first trenches 116. Form. In this case, upper surfaces of the second oxide layer patterns 126 are lower than surfaces of the first active patterns 112.

Openings 128 defined by the second mask patterns 106 and the liner layer 122 are formed on the second oxide layer patterns 126.

Referring to FIG. 8, the first liner layer patterns 130 are formed by etching the liner layer 122 exposed by the second oxide layer patterns 126.

The first liner layer patterns 130 are formed on a portion of inner surfaces of the first trenches 116. In more detail, the liner layer portion etched by the etching process may include a portion exposed by the second oxide layer patterns 126, that is, a liner layer portion formed on an upper portion of the first trenches 116. A portion of the liner layer formed along the surface of the first mask patterns 104.

Here, the liner layer includes a nitride, and the second oxide layer patterns 126 include an oxide, thereby having an etching selectivity with respect to the same etching solution. By using this, the second oxide layer patterns 126 are hardly etched while only the liner layer exposed by the second oxide layer patterns 126 is etched, so that the second oxide layer patterns 126 are etched. The covered liner film portion is not substantially etched.

Accordingly, first liner layer patterns 130 may be formed in portions of the first trenches 116.

Meanwhile, the first oxide layer 120 may be formed on the surfaces of the first mask patterns 104 to prevent the first mask patterns 104 from being etched while a portion of the liner layer is etched. . Accordingly, the first liner layer patterns 130 expose portions of the first mask layers 104 and the first oxide layer 120 formed in the first trenches.

Referring to FIG. 9, a third oxide layer 132 is formed to fill the openings 128 on the second oxide layer patterns 126.

The third oxide layer 132 may include USG, BPSG, PSG, FOX, PE-TEOS, TOSZ, FSG, and the like, and may include substantially the same material as the second oxide layer.

Next, the upper portion of the third oxide film 132 is polished. Examples of the polishing process include a chemical mechanical polishing process, an etch-back or a chemical mechanical polishing and an etch-back mixing process.

Here, the third oxide film 132 is selectively formed only in the first region of the substrate 100. In addition, the third oxide film 132 has an upper surface at a position substantially the same as an upper surface of the second oxide film formed in the second region of the substrate 100.

Referring to FIG. 10, an upper portion of the third oxide layer 132 of the first region of the substrate 100 and an upper portion of the second oxide layer 126 of the second region of the substrate 100 are etched.

By etching the upper portions of the second oxide layer and the third oxide layer 132, the first field oxide structure is substantially the same as or higher than the upper surfaces of the first active patterns 112 in the first region of the substrate 100. The field 134 is formed, and the second field oxide layer structures 138 substantially the same as or higher than the upper surfaces of the second active patterns 114 are formed in the second region of the substrate 100. In this case, the first field oxide layer patterns 134 may include the second oxide layer patterns 126 and third oxide layer patterns (not shown).

Subsequently, the first mask patterns 104 and the second mask patterns 106 exposed by the first field oxide layer patterns 134 and the second field oxide layer patterns 138 are removed.

In this case, before removing the second mask patterns 106, the liner layer formed along the surface of the second mask patterns 106 is first etched. In particular, a portion of the liner layer formed on the upper portions of the second trenches 118 may be etched together while the liner layer formed along the surface of the second mask patterns 106 is etched to form a portion of the inside of the second trenches 118. Second liner layer patterns 136 are formed on the substrate.

Here, gaps 140 are generated between the second liner layer patterns 136 and the second field oxide layer patterns 138. This is because as described above, the liner layer formed on the upper portions of the second trenches 118 is etched while the second mask patterns 106 are removed.

As a result, first active patterns 112, first field oxide layer patterns 134 contacting upper surfaces of the first active patterns 112, and the first area of the substrate 100 may be formed. First liner layer patterns 130 may be formed between the first active patterns 112 and the first field oxide layer patterns 134.

In the second region of the substrate 100, second active patterns 114, second field oxide pattern 138 spaced apart from upper surfaces of the second active patterns 114, and the second area. Second liner layer patterns 136 are formed between the active patterns 114 and the second field oxide layer patterns 138. In this case, gaps 140 are formed between upper surfaces of the second active patterns 114 and upper surfaces of the second field oxide patterns 138.

By performing the above process, the formation of the gaps 140 is suppressed, such as the first active patterns 112 and the first field oxide layer patterns 134, and the second active patterns 114 and the second field oxide layer. Like the patterns 138, the field oxide structure having the structure in which the gaps 140 are formed may be formed together.

As described above, according to a preferred embodiment of the present invention, while removing a portion of the liner film located in the first area of the substrate to form the first liner film pattern, by masking the second area of the substrate, The first field oxide layer patterns in which gap generation is suppressed and the second field oxide layer patterns in which a gap with the active pattern is formed may be formed together.

As a result, an easier process may be performed to form active patterns, a structure in which gap generation is suppressed, and a structure in which gaps are generated, thereby shortening the process time and improving productivity.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (8)

Etching the substrate to form a first trench and a second trench by using a mask pattern formed on the substrate as an etching mask; Forming a first oxide film along a profile of inner surfaces of the first trench and the second trench; Forming a liner layer having an etch selectivity with the first oxide layer along a profile of surfaces of the first and second trench inner surfaces and the mask patterns on which the first oxide layer is formed; Forming a second oxide layer filling the first trench and the second trench; Etching a portion of an upper portion of the second oxide layer to fill the first trench to form a third oxide layer having a lower upper surface than the substrate; Selectively etching the liner layer exposed by the third oxide layer to form a first liner layer pattern on a portion of the inner side of the first trench; Forming a fourth oxide film on the third oxide film; And And removing a portion of the liner layer on the inner side of the first trench and forming the second liner layer pattern on the inner side of the second trench. The method of claim 1, further comprising forming a pad oxide layer on the substrate before forming the mask pattern. The method of claim 1, wherein the liner film comprises nitride. The method of claim 1, wherein the first oxide film is formed by an oxidation process. The method of claim 1, wherein the first oxide layer extends along a surface of the mask pattern. 6. The method of claim 5, wherein the first oxide film is formed by a plasma oxidation or deposition process. The method of claim 1, wherein the second oxide film is formed by a deposition process or a spin coating process. The method of claim 1, wherein before removing the mask pattern, And etching the upper portion of the second oxide film filling the first trench and the fourth oxide film filling the second trench to expose the liner layer portion on the mask pattern. Method of formation.

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