KR20070001338A - Method of manufacturing etching mask and method of manufacturing the minor pattern - Google Patents

Abstract

An etch mask manufacturing method and a pattern manufacturing method using the same are provided to obtain an excellent profile and a small CD(Critical Dimension) from a fine pattern by forming an enhanced etch mask structure using a first and second photoresist patterns. A second mask layer and a first mask layer are sequentially formed on a substrate(S110). A first photoresist pattern is formed on the first mask layer(S120). A first mask pattern is formed by performing a dry etching process on the first mask layer using the first photoresist pattern as an etch mask(S130). The first photoresist pattern is removed therefrom(S140). A second photoresist pattern is formed on the resultant structure(S150). A second mask pattern is formed on the resultant structure by performing dry etching on the second mask layer using the second photoresist pattern as an etch mask(S160).

Description

Etch mask manufacturing method and pattern manufacturing method using the same {METHOD OF MANUFACTURING ETCHING MASK AND METHOD OF MANUFACTURING THE MINOR PATTERN}

1 is a flowchart illustrating a method of manufacturing an etch mask according to an embodiment of the present invention.

2 to 7 are cross-sectional views illustrating a method of forming a fine pattern using the etching mask manufacturing method illustrated in FIG. 1.

The present invention relates to an etching mask manufacturing method and a fine pattern manufacturing method using the same. More specifically, the present invention relates to an etching mask having a formation interval smaller than that of a conventional photoresist pattern and a method of manufacturing a fine pattern using the same.

As high integration of semiconductor devices is required, processing technologies for realizing ultra-fine patterns having a line width of 100 nm or less are on the rise. The processing technology for forming the fine pattern has been mainly made by a photolithography technique using a photoresist, a photosensitive material. The photolithography technique is performed to form a photoresist pattern by performing a photoresist film formation process, an alignment / exposure process of patterns to be formed on the photoresist film, and a photoresist development process.

The alignment / exposure process includes aligning a mask on which a predetermined circuit pattern is formed on a substrate on which a photoresist film is formed, and then having an image of the circuit pattern of the mask so that a photochemical reaction occurs in the photoresist film. It is a process of projecting light on a photoresist film. As a result, the photoresist film is selectively changed in molecular structure so as to correspond to the image of the circuit pattern of the mask. Then, a photoresist pattern is formed on the wafer through a developing process. The developing step is a step of forming a photoresist pattern having a shape corresponding to the circuit pattern by selectively removing or remaining the photoresist deformed by the exposure process.

The resolution of the photoresist pattern formed by the above-described photolithography process depends on Rayleigh's equation (R = k1λ / NA, R: limit resolution, λ: wavelength, k1: constant, NA: numerical aperture of the lens). That is, the shorter the wavelength of light used, the better the photoresist pattern has and the smaller the line width. In the early 1980s, photoresist patterns with a resolution of about 500 to 350 nm were formed using an exposure apparatus to which G-line light having a wavelength of 436 nm and I-line light having a wavelength of 365 nm were applied. The introduction of an exposure technique using KrF light having a wavelength or ArF light having a wavelength of 198 nm enables the formation of a photoresist pattern having excellent resolution.

The method of manufacturing the photoresist pattern using the above-described light will be described in detail. First, a photoresist including a photosensitive polymer is coated on a substrate to have a uniform thickness, and then heat treated to form a photoresist film. Subsequently, after the substrate on which the photoresist film is formed is interposed in an exposure apparatus, a selective exposure process using a light source having a wavelength of about 193 nm or less is performed. Thereafter, the photoresist pattern was formed by sequentially developing, cleaning and baking the exposed photoresist film.

However, the above-described method has a problem in that it is difficult to form fine patterns arranged at intervals of 100 nm or less because only the photoresist pattern can be formed in an array that is sequentially repeated at intervals of 100 nm or more.

Accordingly, an object of the present invention for solving the above problems is to provide a method of manufacturing an etch mask consisting of a pattern arranged at a fine interval using the first photoresist pattern and the second photoresist pattern.

Another object of the present invention is to provide a method of manufacturing a pattern having a fine line width by applying a photoresist pattern to a method of manufacturing fine patterns arranged at minute intervals by applying the etching mask formed by the above method.

According to the etching mask manufacturing method according to an embodiment of the present invention for achieving the above object, the second mask film and the first mask film are sequentially formed on the substrate. A first photoresist pattern is formed on the first mask layer at first intervals. The first mask layer exposed to the first photoresist pattern is dry-etched to form a first mask pattern. The first photoresist pattern is removed. A second photoresist pattern may be formed on the second mask layer, wherein the second photoresist pattern is formed at a second interval smaller than the first interval and is formed between the upper surface of the first mask pattern and the second mask layer exposed between the first mask pattern. The second mask pattern exposed by the second photoresist pattern may be dry-etched to form a second mask pattern, thereby forming an etch mask having an interval of a small width.

The first mask layer and the second mask layer applied to remove the etch mask are applied with a nitride film, and the second mask pattern is formed on a substrate exposed between an upper surface of the first mask pattern and the mask pattern. do.

According to the pattern manufacturing method according to an embodiment of the present invention for achieving the above another object, the second mask film and the first mask film are sequentially formed on the substrate on which the target film is formed. A first photoresist pattern is formed on the first mask layer at first intervals. The first mask layer exposed to the first photoresist pattern is dry-etched to form a first mask pattern. The first photoresist pattern is removed. A second photoresist pattern is formed on the upper surface of the first mask pattern and the upper surface of the second mask layer exposed between the first mask pattern and arranged at a second smaller interval of the first interval. The second mask layer exposed to the second photoresist pattern is dry-etched to form a second mask pattern. The second photoresist pattern is removed to form an etch mask including the first mask pattern and the second mask pattern. Dry etching the target film exposed to the etching mask may form the target film patterns arranged at minute intervals.

The target film may be any one selected from the group consisting of an oxide film, polysilicon, a metal film, and a metal nitride film.

Accordingly, the etching mask manufacturing method and the pattern manufacturing method using the same according to the present invention can form an etching mask and a pattern arranged at a superior profile and fine intervals using existing exposure equipment and exposure techniques. That is, the above-described method can prevent an increase in the process cost when manufacturing a semiconductor device having a design rule of 60nm or less.

In the accompanying drawings, the dimensions of the substrate, layer (film), photoresist, mask or pattern is shown in an enlarged scale than actual for clarity of the invention. In the present invention, each layer (film), mask, photoresist or pattern is a "top", "on", "bottom", "top" or "bottom" of the substrate, each layer (film), region or pattern. When referred to as being formed in a "layer, film, photoresist or pattern, it is meant to be formed on or beneath each layer (film), mask or patterns, or on another layer (film). Other masks or other patterns may be additionally formed on the substrate. Further, where each layer (film), mask, spacing or pattern is referred to as "first", "second" and / or "third", it is not intended to limit these members but only each layer (film), To distinguish between masks, gaps, or patterns. Thus, "first", "second" and / or "third" may be used selectively or interchangeably for each layer (film), spacing, or pattern, respectively.

Etch mask manufacturing method.

1 is a flowchart illustrating a method of manufacturing an etch mask according to an embodiment of the present invention.

Referring to FIG. 1, a second mask film and a first mask film are sequentially formed on a substrate (step S110). The first mask film and the second mask film are nitride films, and examples of the nitride film include a silicon nitride film and a silicon oxynitride film.

A first photoresist pattern is formed on the first mask layer at first intervals (step S120).

Specifically, after spin-coating a photoresist on the substrate on which the first mask film is formed, the substrate on which the photoresist is applied is soft baked to form a first photoresist film. The photoresist comprises at least one photoacid generator, blocking group, photosensitive resin and solvent that selectively react with light. The soft baking process is about 110 to 120 ° C. heating to increase the adhesion of the photoresist coated on the substrate and to evaporate the solvent of the photoresist.

After the reticle is interposed in the exposure apparatus, the light transmitted through the reticle is reduced and projected onto the first photoresist film to selectively expose the photoresist film. In this case, the light may be KrF light having a wavelength of 248nm or less, or ArF light having a wavelength of 193nm or less. In this embodiment, ArF light having a wavelength of 193 nm or less is used.

After the substrate on which the first photoresist film on which the exposure process has been performed is post-baked, the first photoresist film is developed using a developer to form a preliminary photoresist pattern. The post-baking step is a step for reducing the amount of solvent remaining in the first photoresist film, and the developing step is a step of selectively dissolving a portion of the first photoresist film selectively exposed by light using a developer. .

A rinse process and a hard baking process for removing the developer remaining on the substrate on which the preliminary photoresist pattern is formed are sequentially performed to form first photoresist patterns arranged at first intervals. For example, the first line width of the first photoresist pattern has a line width of about 50 nm, and the first photoresist pattern is disposed at an interval of about 120 nm, which is a first interval.

The first mask layer exposed to the first photoresist pattern is etched to form a first mask pattern (step S130).

In detail, the first mask pattern may be formed by performing a dry etching process to expose the top surface of the second mask layer to the first mask layer exposed to the first photoresist pattern. Examples of the dry etching process may include a dry etching process using plasma, a dry etching process using sputtering ions, and a dry etching process using etching ions. The first mask pattern has the same line width as the first photoresist pattern and is arranged at the same first interval as the first photoresist pattern.

The first photoresist pattern is removed to expose the first mask pattern to the substrate (step S140). The first photoresist pattern may be removed by performing a plasma ashing process using oxygen gas or a plasma ashing process using ozone gas. In addition, a strip process using a cleaning liquid may be further performed.

A second photoresist pattern is formed on the top surface of the first mask pattern and the top surface of the second mask film exposed between the first mask patterns and is arranged at a second smaller interval of the first gap (step S150). ).

Specifically, after spin-coating a photoresist to cover the first mask pattern on the second mask layer on which the first mask pattern is formed, a second photoresist layer is formed by soft baking the substrate on which the photoresist is applied.

A photolithography process is performed on the second photoresist film to form second photoresist patterns arranged at a second interval smaller than the first interval. The second photoresist pattern is formed on the top surface of the first mask pattern and the top surface of the second mask layer exposed between the first mask pattern. Since the photolithography process for forming the second photoresist pattern has been described in detail above, it is omitted to avoid duplication.

 For example, the second photoresist pattern has a first line width that is the same as the first mask pattern of the second photoresist pattern and is disposed at an interval of about 60 nm, which is a second interval that is about 0.5 times smaller than the first interval of the first photoresist pattern.

The second mask layer exposed to the second photoresist pattern is dry-etched to form a second mask pattern (step S160).

In detail, the second mask pattern may be formed by performing a dry etching process on the upper surface of the substrate to expose the second mask layer exposed to the second photoresist pattern. Examples of the dry etching process may include a dry etching process using plasma, a dry etching process using sputtering ions, and a dry etching process using etching ions. The second mask pattern has the same line width as that of the second photoresist pattern and is arranged at the same second interval as the second photoresist pattern.

The second photoresist pattern is removed to form an etching mask including the first mask pattern and the second mask pattern (step S170). The second photoresist pattern may be removed by performing a plasma ashing process using oxygen gas or a plasma ashing process using ozone gas. In addition, the strip process using the cleaning solution can be further performed to remove.

The etching mask formed by removing the second photoresist pattern has a structure in which a third mask pattern having a structure in which a first mask pattern is stacked on the second mask pattern and the second mask pattern is repeatedly formed on the substrate. . That is, the etching mask is formed by arranging a second mask pattern having the first height and a third mask pattern having a second height greater than the first height on the substrate at second intervals.

The etching mask manufacturing method described above may form an etching mask having a pattern arranged at minute intervals using a conventional photoresist technology and a conventional exposure apparatus. Therefore, patterns having a fine line width can be formed, thereby reducing the manufacturing cost of the semiconductor device and increasing the productivity of the semiconductor device.

Fine pattern manufacturing method

2 to 7 are cross-sectional views illustrating a method of forming a pattern using the etching mask forming method illustrated in FIG. 1.

Referring to FIG. 2, the second mask layer 112 and the first mask layer 114 are sequentially formed on the substrate 100 on which the target layer 110 is formed. Examples of the target film 110 include a metal film, an oxide film, a polysilicon film, a barrier film, and the like. The target film 110 may be used alone or in combination thereof.

Examples of the metal film may include a tungsten film, an aluminum film, a titanium film, a copper film, and the like, and the target film may be an applicable film for manufacturing DRAM, SRAM, or flash memory. It may have a structure in which a metal film and a second oxide film are sequentially stacked on the first oxide film. The second mask film and the first mask film are silicon nitride films.

Referring to FIG. 3, a first photoresist pattern 116 is formed on the first mask layer 114 to be spaced apart at a first interval P1. In this embodiment, the line width of the first photoresist pattern 116 has a line width of about 50 nm, and the first photoresist pattern is disposed at an interval of about 120 nm, which is the first interval P1.

Referring to FIG. 4, the first mask layer exposed to the first photoresist pattern 116 is etched to form a first mask pattern 114a. The first mask pattern 114a is formed by dry etching the first mask layer exposed to the first photoresist pattern until the top surface of the second mask layer 116 is exposed. Thereafter, the plasma ashing / or stripping process is performed to remove the first photoresist pattern from the first mask pattern. The first mask pattern 114a has the same line width as the first photoresist pattern and is arranged at the same first interval P1 as the first photoresist pattern.

Referring to FIG. 5, a second portion formed on an upper surface of the second mask layer 112 exposed between the upper surface of the first mask pattern 114a and the first mask pattern is smaller than the first interval P1. A second photoresist pattern 116 is formed, which is arranged at intervals P2.

Specifically, after spin coating the photoresist to cover the first mask pattern on the second mask layer 112 on which the first mask pattern 114a is formed, the photoresist-coated substrate is soft baked to perform a second photo. A resist film is formed.

A photolithography process is performed on the second photoresist film to form a second photoresist pattern arranged at a second interval P2 smaller than the first interval P1. The second photoresist pattern is formed on the top surface of the first mask pattern and the top surface of the second mask layer exposed between the first mask pattern. Since the photolithography process for forming the second photoresist pattern has been described in detail above, it is omitted to avoid duplication.

 For example, the second photoresist pattern 116 may have the same first line width as that of the first mask pattern 112a and may be a second interval that is about 0.5 times smaller than the first interval of the first photoresist pattern 114. Spaced apart at intervals of 60 nm.

Referring to FIG. 6, the second mask layer 112 exposed to the second photoresist pattern 114 is dry-etched to form a second mask pattern 112a.

Specifically, the second mask pattern 112a is formed by dry etching the second mask layer exposed to the second photoresist pattern to expose the top surface of the substrate. The second mask pattern 112a has the same line width as that of the second photoresist pattern 116 and is arranged at the same second interval P2 as the second photoresist pattern 116. The second photoresist pattern is removed to form an etch mask 120 including the first mask pattern 114a and the second mask pattern 112a.

The etching mask formed by removing the second photoresist pattern may include a second mask pattern 112a and a third mask pattern 119 having a structure in which a first mask pattern 114a is stacked on the second mask pattern 112a. ). That is, in the etching mask 120, the second mask pattern 112a having the first height and the third mask pattern 119 having a second height greater than the first height are repeated on the target layer at a second interval. It has an arranged structure.

Referring to FIG. 7, the target layer 110 exposed to the etching mask 120 is dry-etched to form the target layer pattern 110a, and then the etching mask is removed from the target layer pattern. The target layer pattern 110a may have the same line width as that of the second mask pattern and the third mask pattern constituting the etch mask, and may also have a second spacing equal to a spaced interval from the second mask pattern and the third mask pattern. P2).

In the method of manufacturing an etching mask and a method of manufacturing a fine pattern using the same, the etching mask may be formed by applying a first photoresist pattern and a second photoresist pattern to reduce the distance between the pattern and the pattern by about 50%. This method can use existing exposure equipment and existing photoresist technology to form fine patterns with better profiles and smaller line widths.

In addition, it can be applied to the manufacturing process of the next-generation highly integrated semiconductor device can secure the competitiveness of semiconductor device manufacturing.

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 (7)

Sequentially forming a second mask film and a first mask film on a substrate; Forming a first photoresist pattern arranged on the first mask layer at a first interval; Dry etching the first mask layer exposed to the first photoresist pattern to form a first mask pattern; Removing the first photoresist pattern; Forming a second photoresist pattern formed on an upper surface of the first mask pattern and an upper surface of the second mask layer exposed between the first mask pattern and arranged at a second interval smaller than the first interval; And And etching the second mask layer exposed to the second photoresist pattern to form a second mask pattern. The method of claim 1, wherein the first mask layer and the second mask layer are nitride films. The method of claim 1, wherein the second mask pattern is formed on an upper surface of the first mask pattern and a substrate exposed between the mask pattern. The method of claim 1, further comprising removing the second photoresist pattern. The method of claim 1, wherein the first interval is twice the second interval. Sequentially forming a second mask film and a first mask film on the substrate on which the target film is formed; Forming a first photoresist pattern arranged on the first mask layer at a first interval; Dry etching the first mask layer exposed to the first photoresist pattern to form a first mask pattern; Removing the first photoresist pattern; Forming a second photoresist pattern formed on an upper surface of the first mask pattern and an upper surface of the second mask layer exposed between the first mask pattern and arranged at a smaller second interval of the first interval; Dry etching the second mask layer exposed to the second photoresist pattern to form a second mask pattern; Removing the second photoresist pattern to form an etch mask including a first mask pattern and a second mask pattern; And Dry etching the target film exposed to the etching mask to form a target film pattern. The method of claim 1, wherein the target film includes any one selected from the group consisting of an oxide film, polysilicon, a metal film, and a metal nitride film.

Images