KR20090131821A - Method of forming fine pattern in a semiconductor device fabricating - Google Patents

Abstract

PURPOSE: A method for forming a fine pattern is provided to prevent deterioration of a semiconductor device by reducing the number of high temperature deposition processes. CONSTITUTION: A first mask film(102) is formed on a substrate(100). A coating film is spin-coated on the first mask film. A photoresist pattern is formed on the coating film. A coating film pattern(104a) is formed by etching the coating film through the photoresist film. A second mask pattern(110a) of a spacer shape is formed to a side wall of the coating film pattern. The coating film pattern is removed. The first mask pattern is formed by etching the first mask film through the second mask pattern.

Description

Method of forming fine pattern in a semiconductor device fabricating}

The present invention relates to a method of forming a fine pattern in the manufacture of a semiconductor device, and more particularly, to a method of forming a mask pattern having a narrower line width than the pattern formed by a photographic process.

In recent years, as semiconductor devices have been highly integrated, line widths of patterns included in semiconductor devices have become smaller. Therefore, in order to form a finer pattern in the manufacture of a semiconductor device, a self alignment double patterning process (hereinafter referred to as 'SADP') and the like have been developed. The SADP process is a process of forming a mask pattern having a narrower line width than a mask pattern formed by a photo process by performing double patterning, and forming a fine pattern using the pattern.

According to the SADP process, since two patterning processes are required to form a mask pattern, the process for forming the mask pattern is very complicated. Therefore, the time and cost for forming the mask pattern are increased.

In addition, in order to form a pattern or a contact having a high aspect ratio by applying the SADP process, the aspect ratio of the mask pattern should also be very high. However, when the mask pattern having a high aspect ratio is formed through the SADP process, a problem such as collapse of the mask pattern frequently occurs.

Moreover, according to the SADP process, it is difficult for the mask pattern to have a desired sidewall profile because several deposition, etching and polishing processes have to be performed to form the mask pattern.

It is an object of the present invention to provide a method of forming a fine pattern in which the process is simplified and defect generation factors are reduced.

In the method for forming a fine pattern according to an aspect of the present invention for achieving the above object, a first mask film is formed on a substrate. A coating film pattern is formed on the first mask film. A second mask pattern having a spacer shape is formed on sidewalls of the coating layer pattern. The coating layer pattern is removed. Next, a first mask pattern is formed by etching the first mask layer using the second mask pattern.

 In an embodiment of the present disclosure, a process of forming an etched film on the substrate may be further performed.

In one embodiment of the present invention, in order to form the coating layer pattern, spin coating a coating layer on the first mask layer. A photoresist pattern is formed on the coating film. The coating layer is etched using the photoresist pattern to form a coating layer pattern.

The coating layer pattern may include carbon.

In an embodiment, the second mask pattern may be formed using a material having an etching selectivity with respect to the first mask layer.

In one embodiment of the present invention, in order to form the second mask pattern, a second mask layer is formed along the surface of the coating layer pattern and the first mask layer. Next, the second mask layer is etched anisotropically to form a spacer-shaped second hard mask pattern.

In one embodiment of the present invention, the deposition process for forming the second mask film may be performed at a temperature lower than the curing temperature of the coating film pattern.

In one embodiment of the present invention, the deposition process for forming the second mask film may be performed at a temperature of 200 to 450 ℃.

In one embodiment of the present invention, the second mask layer may be formed of a polysilicon material doped with boron in situ. Examples of the silicon source that can be used in the deposition process for forming the boron doped polysilicon material include SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , and the like. These can be used individually or in mixture. In addition, examples of the boron source that may be used in the deposition process may include BCl ₃ , B ₂ H ₆ , and the like. These can be used individually or in mixture.

In one embodiment of the present invention, the second mask layer may be formed of a silicon germanium material doped with boron in situ. In the deposition process for depositing the boron doped silicon germanium material, examples of the silicon source that can be used in the deposition process for forming the boron doped polysilicon material include SiH ₄ , Si ₂ H ₆ , Si ₃ H _8, and the like. Can be mentioned. Examples of the boron source that can be used in the deposition process include BCl ₃ , B ₂ H ₆ and the like. These can be used individually or in mixture. In addition, examples of the germanium source that can be used in the deposition process may include GeH ₄ .

As described, according to the method of the present invention, a fine pattern can be formed by a simple process. Therefore, the process cost and the process time for forming the fine pattern are reduced. This makes it possible to manufacture highly integrated semiconductor devices at low cost.

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

In the present invention, like reference numerals are used for like elements in describing the drawings. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

In the present invention, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described on the specification, but one or more other features. It should be understood that it does not preclude the presence or possibility of additions or numbers, steps, actions, components, parts or combinations thereof.

In the present invention, each layer (film), region, electrode, pattern or structures is formed on, "on" or "bottom" of the object, substrate, each layer (film), region, electrode or pattern. When referred to as being meant that each layer (film), region, electrode, pattern or structure is formed directly over or below the substrate, each layer (film), region or patterns, or other layer (film) Other regions, different electrodes, different patterns, or different structures may be additionally formed on the object or the substrate.

With respect to the embodiments of the present invention disclosed in the text, specific structural to functional descriptions are merely illustrated for the purpose of describing embodiments of the present invention, embodiments of the present invention may be implemented in various forms and It should not be construed as limited to the embodiments described in.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

1 to 7 are schematic cross-sectional views showing a method of forming a fine pattern according to a preferred embodiment of the present invention.

Referring to FIG. 1, an etched film (not shown) is formed on the semiconductor substrate 100. The semiconductor substrate 100 may be a single crystal silicon substrate. When the object to be etched is the semiconductor substrate 100, the etched film is not formed.

A first mask layer 102 is formed on the etching target layer. The first mask layer may be formed of a material having an etching selectivity with respect to the etching target film. That is, the first mask layer 102 should be formed of a material that is hardly etched when the etching layer is etched. For example, examples of the material that can be used as the first mask layer 102 include silicon oxide, silicon nitride, and the like. The first mask film 102 is preferably formed of a single film of these materials. In the present embodiment, the first mask layer 102 may be formed by depositing silicon oxide through a PE-CVD process.

A coating film 104 is formed on the first mask film 102. The coating film 104 may be formed of a carbon spin on hardmask (C-SOH) material made of about 99% carbon. Specifically, the coating layer may be formed by spin-coating the carbon spin-on hard mask material on the first mask layer 102 and baking the same at a temperature of about 350 to 450 ° C. The coating film 104 is patterned through a subsequent process to define the position and height of the second mask pattern for patterning the first mask film 102. Therefore, the coating film 104 is formed to have a height higher than the height of the second mask pattern to be formed or the same as the height of the second mask pattern to be formed.

An anti-reflection film 106 is formed on the coating film 104. The anti-reflection film is provided to minimize reflection between the subsequently formed photoresist film and the substrate. The anti-reflection film may be formed by depositing silicon oxynitride by chemical vapor deposition. However, the anti-reflection film 106 may be omitted to simplify the process.

Referring to FIG. 2, a photoresist pattern 108 is formed by coating a photoresist on the antireflection film 106 and patterning the photoresist by a photolithography process.

The photoresist pattern 108 has the same line width as the spacing between the hard mask patterns to be formed. In addition, the photoresist pattern 108 is formed to be spaced apart from each other at intervals of about three times the line width of the hard mask pattern to be formed.

The photoresist pattern 108 should be located between the hard mask patterns to be formed. Therefore, a portion under the portion where the photoresist pattern 108 is formed is a portion between the hard mask patterns.

Referring to FIG. 3, the antireflection film 106 and the coating film 104 are sequentially anisotropically etched using the photoresist pattern 108 as an etching mask. The coating layer pattern 104a is formed on the first mask layer 102 through the anisotropic etching process.

When the anisotropic etching process is performed, not only the coating layer 104 but also the photoresist pattern 108 and the anti-reflection film 106 disposed under the photoresist pattern 108 are also removed. Therefore, when the coating film pattern 104a is formed through the anisotropic etching, the photoresist pattern 108 and the anti-reflection film 106 are almost removed.

Thereafter, some of the remaining photoresist pattern 108 and the anti-reflection film 106 are removed. The coating layer pattern 104a may not be removed during the removal process. In contrast, when the photoresist pattern 108 and the anti-reflection film 106 are completely removed by the anisotropic etching process, a separate process for removing the photoresist pattern 108 and the anti-reflection film 106 may be performed. You do not have to do it.

Referring to FIG. 4, a spacer layer 106 is formed along a sidewall, an upper surface of the coating layer pattern 104a, and an upper surface of the first mask layer 102 between the coating layer pattern 104a. The spacer layer 110 is used as an etching mask to form a hard mask pattern through a subsequent process. Therefore, the first mask layer 102 is preferably formed of a material having an etching selectivity. In addition, the spacer layer 110 should be formed to have the same thickness as the width of the hard mask pattern to be formed.

Since the coating pattern is thermally unstable, a thermal budget may be generated in the coating pattern 104a when the spacer layer 110 is formed. Therefore, the deposition process for forming the spacer film 110 is preferably formed at a temperature lower than the temperature for baking the coating film pattern 104a.

When the spacer layer 110 is formed at a temperature of 450 ° C. or higher, the thermally unstable coating layer pattern 104a may be collapsed when the spacer layer 110 is formed. Therefore, the spacer film 110 is preferably deposited at a low temperature of 450 ℃ or less.

As described above, examples of the material having a deposition selectivity with respect to the first mask layer 102 and having an etching selectivity with respect to the first mask layer 102 include in situ boron-doped polysilicon, in-situ boron-doped silicon germanium, and the like. Can be mentioned. The first mask film 102 is preferably formed of a single film of these materials.

Specifically, the spacer film 110 formed of the in-situ boron-doped polysilicon may be formed through a deposition process using a boron source gas and a silicon source gas as a reaction gas. The deposition may be performed through a CVD process or an ALD process. Examples of the boron source gas that may be used in the deposition process include BCl ₃ , B ₂ H ₆ , and the like. These may be used alone or in combination of two or more. In addition, examples of the gas that may be used as the silicon source include SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , and the like. These may be used alone or in combination of two or more.

The boron source gas is decomposed at a low temperature of 200 ° C. or lower to promote the reaction. Therefore, in situ boron doped polysilicon film may be deposited at a temperature of 300 to 450 ℃.

The spacer film made of in situ boron-doped silicon germanium may be formed through a deposition process using boron source gas, silicon source gas, and germanium source gas as a reaction gas. The deposition may be performed through a CVD process or an ALD process. Examples of the boron source gas that may be used during the deposition include BCl ₃ , B ₂ H ₆ , and the like. These may be used alone or in combination of two or more. Examples of the silicon source gas that may be used in the deposition include SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , and the like. These may be used alone or in combination of two or more. In addition, an example of the germanium source gas that may be used in the deposition may include GeH ₄ . Since the germanium source gas also reacts at a low temperature, the in-situ boron-doped silicon germanium film may be deposited at a temperature of 300 to 450 ° C.

In contrast, undoped polysilicon and phosphorus doped polysilicon may be deposited at a temperature of about 530 ° C. Therefore, the undoped polysilicon and the polysilicon doped with phosphorus are not suitable as the spacer film.

Referring to FIG. 5, the spacer layer 110 is anisotropically etched to form a second mask pattern 110a having a spacer shape. Two second mask patterns 110a are formed between the coating layer patterns 104a.

The second mask pattern 110a has the same line width as the thickness of the spacer layer 110. In addition, since two second mask patterns 110a are formed between the coating film patterns 104a formed by the photographing process, the second mask pattern 110a is about 1 of the minimum line width that can be formed by the photographing process. It can have a line width of twice. Therefore, the second mask pattern 110a may have a fine line width of about 20 to 40 nm.

Referring to FIG. 6, the coating film pattern 104a provided between the second mask patterns 110a is removed. The coating pattern 104a may be removed through an ashing and stripping process. The first mask layer 102 is exposed between the second mask patterns 110a by removing the coating layer pattern 104a.

As described above, only the deposition of the spacer layer 110, the etching of the spacer layer 110, and the removal of the coating layer pattern 104a are performed to form the second mask pattern 110a. That is, in the conventional double patterning process, complex steps such as two mask film forming processes, one patterning process, an anti-reflection film removing process, a sacrificial film forming process, a planarization process, and a sacrificial film anisotropic etching process should be performed. According to one embodiment, only one deposition, etching, and coating layer pattern removing process is performed, thereby simplifying the process.

In addition, in the conventional double patterning process, since the deposition process is performed several times, the high temperature process time is increased, and heat defects are likely to occur. In addition, the process time becomes longer and the cost required for the process increases. On the other hand, according to one embodiment of the present invention, the high temperature process is reduced, so that deterioration of the device is hardly generated, and the cost required to perform the process is also reduced.

In addition, since the process of removing the sacrificial film is not performed when the second mask pattern 110a is formed, a phenomenon in which the sidewall profile is deteriorated while the sacrificial film is removed conventionally does not occur. Accordingly, the second mask pattern 110a has a better sidewall profile than the mask pattern formed by conventional double patterning.

Referring to FIG. 7, the first mask pattern 102a is formed by anisotropically etching the first mask layer 102 exposed between the second mask patterns 110a. The first mask pattern 102a has a finer line width than the mask pattern formed by a normal photo process.

After forming the first mask pattern 102a, the second hard mask pattern is removed.

Thereafter, although not shown, a pattern is formed by etching the etched film using the first mask pattern. If the etched film is a substrate, the substrate is etched.

According to the present embodiment, an etching mask pattern having a fine line width can be formed. In addition, a desired pattern may be formed by using the etching mask pattern.

Experimental Comparative Sample Preparation

Comparative Sample 1 was prepared by depositing an undoped polysilicon film without introducing a boron source gas. In addition, the growth rate (Growth rate) of the undoped polysilicon film was measured. The deposition conditions of the undoped polysilicon film for obtaining Comparative Sample 1 are shown in Table 1 below.

Experimental Sample Preparation

In order to compare the deposition rate of the undoped polysilicon film of Comparative Sample 1, samples 1 to 6 were obtained by depositing an in-situ boron doped polysilicon film according to the method of the present invention. In addition, the polysilicon film growth rate in each sample was measured. Samples 1 to 6 are slightly different from the deposition conditions for depositing the in-situ boron-doped polysilicon film, and the deposition conditions for each sample are shown in Table 1 below.

TABLE 1

In the case of the present invention, the boron doped polysilicon film used as the spacer film should be deposited at a low temperature of about 450 ° C. or less, which is the baking temperature of the coating film. That is, the polysilicon film should be deposited at a sufficiently fast rate at a low temperature of about 450 ° C.

8 is a graph showing the growth rate of the polysilicon film during deposition of each sample in Comparative Samples and Samples 1 to 6. FIG.

Referring to FIG. 8, when the undoped polysilicon was formed at a low temperature of 450 ° C. without introducing the boron source gas as in the comparative sample, the thin film did not grow at all.

However, when the boron source gas is introduced as in Samples 1 to 6, it can be seen that the growth rate is increased in proportion to the inflow amount of the boron source gas. Specifically, it can be seen that the thin film is deposited at a growth rate of 20 to 60 μs / min at a low temperature of 450 ° C. by introducing the boron source gas.

From the above results, it can be seen that the in-situ boron doped polysilicon film can be used as the spacer film. As a result, it was found that a mask pattern having a fine line width could be formed. On the other hand, in the case of the boron doped polysilicon film was not deposited at a temperature of 450 ℃ it can be seen that it can not be used as a spacer film.

The mask pattern according to the present invention can be used as an etching mask for forming a wiring having a fine line width, a contact hole having a narrow opening width, and the like. In particular, in the manufacture of semiconductor devices, a mask pattern for forming contact holes having a high aspect ratio and repeatedly arranged with the same wiring or a predetermined interval of the width of the line and the space may be used.

 Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1 to 7 are schematic cross-sectional views showing a method of forming a fine pattern according to a preferred embodiment of the present invention.

8 is a graph showing the growth rate of the polysilicon film during deposition of each sample in Comparative Samples and Samples 1 to 6. FIG.

Claims (12)

Forming a first mask film on the substrate; Forming a coating pattern on the first mask layer; Forming a spacer-shaped second mask pattern on sidewalls of the coating layer pattern; Removing the coating pattern; And Forming a first mask pattern by etching the first mask layer using the second mask pattern. The method of claim 1, further comprising forming an etched film on the substrate. The method of claim 1, wherein the forming of the coating layer pattern comprises: Sputter coating a coating film on the first mask film; Forming a photoresist pattern on the coating film; And And forming a coating layer pattern by etching the coating layer using the photoresist pattern. The method of claim 1, wherein the coating pattern comprises carbon. The method of claim 1, wherein the second mask pattern is formed using a material having an etch selectivity with respect to the first mask layer. The method of claim 1, wherein the forming of the second mask pattern comprises: Forming a second mask film along the coating pattern and the surface of the first mask film; And And etching the second mask layer anisotropically to form a second hard mask pattern having a spacer shape. The method of claim 6, wherein the deposition process for forming the second mask layer is performed at a temperature lower than a curing temperature of the coating layer pattern. The method of claim 6, wherein the deposition process for forming the second mask layer is performed at a temperature of 200 to 450 ° C. 8. The method of claim 6, wherein the second mask layer is formed of a polysilicon material doped with boron in situ. The method of claim 9, wherein in the deposition process for depositing the second mask layer, the silicon source uses at least one selected from the group consisting of SiH ₄ , Si ₂ H _6, and Si ₃ H ₈ , and the boron source is BCl _3. And at least one selected from the group consisting of B ₂ H ₆ . The method of claim 6, wherein the second mask layer is formed of a silicon germanium material doped with boron in situ. The method of claim 11, wherein in the deposition process for depositing the second mask layer, the silicon source uses at least one selected from the group consisting of SiH ₄ , Si ₂ H _6, and Si ₃ H ₈ , and the boron source is BCl _3. And at least one selected from the group consisting of B ₂ H ₆ , and the germanium source uses GeH ₄ gas.

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