KR100670835B1 - Method for fabrication of nanoimprint mold - Google Patents

Abstract

A method for fabricating a nano-imprint mold is provided to manufacture a quartz NIL(Nano-Imprint Lithography) mold by using a mold such as a silicon substrate. An E-beam resist is coated on a substrate and an E-beam resist pattern is formed on the first substrate by performing an E-beam lithography process(S200). A photoresist pattern is formed on the first substrate by performing a photo-lithography process(S300). A pattern is formed on the first substrate by using the E-beam resist pattern and the photoresist pattern(S400). A NIL mold is formed by printing the pattern of the first substrate on a second substrate for mold(S500,S600).

Description

Method for fabrication of nanoimprint mold

1 is a flowchart schematically illustrating a method for manufacturing a nanoimprint mold of the present invention.

2A to 2F are cross-sectional views of a method for fabricating a nanoimprint mold according to a first embodiment of the present invention.

3A to 3G are cross-sectional views of a method for fabricating a nanoimprint mold according to a second embodiment of the present invention.

4A is an AFM photograph of a silicon mold manufactured according to the first embodiment of the present invention, and a two-dimensional graph thereof.

4B are two-dimensional and three-dimensional AFM images of a silicon mold according to a second embodiment of the present invention.

FIG. 5A is an AFM photograph of a quartz NIL mold formed through a NIL process using the silicon mold of FIG. 4A and a two-dimensional graph thereof.

5B is an AFM photograph of a quartz NIL mold having a pattern of several μm and a two-dimensional graph thereof.

5C is a two-dimensional optical photograph of a quartz NIL mold using a silicon mold having the same pattern as that of FIG. 4B according to a second embodiment of the present invention.

<Description of main parts of drawing>

100: first substrate .............. 100a, 100c: patterned first substrate

100b: First substrate on which alignment key is formed ... 120: Alignment key

200: E-beam resist ........................ 200a: E-beam resist pattern

300: PR ......................... 300a: PR pattern

500: second substrate

500a, 500b: patterned second substrate or NIL mold

600: NIL Resist ......... 600a: NIL Resist Pattern

TECHNICAL FIELD The present invention relates to nanoimprint technology, and more particularly, to a method of fabricating a nanoimprint mold essential for nanoimprint technology.

Representative methods for fabricating nanostructures below 100nm include E-beam lithography (EBL), focused ion beam lithography (FIBL), nanoimprint lithography (NIL), and deep ultraviolet lithography. (deep UV (DUV) lithography). Meanwhile, extreme UV lithography, X-ray lithography, and hologram lithography or laser interference lithography (LIL) are being developed as next generations.

In the case of EBL or FIBL having a resolution of several nanometers (nm), the conductivity or structure of the substrate is greatly influenced by the electromagnetic characteristics of the accelerated electrons or ions. The disadvantage is that it is quite slow.

In addition, DUV or EUV lithography, which is typically used in a semiconductor process and forms a pattern in a large area of a wafer in one process, is very expensive in process equipment, expensive to manufacture a photo mask, and exposed to exposure. ), It is difficult to use a flexible substrate or a material which is affected by a developer used to form a pattern afterwards.

On the other hand, X-ray lithography, which is developed in the next generation, can be compared to EBL or FIBL by a few nm in resolution limited by diffraction limit, compared to optical lithography. Since the source itself cannot be enlarged, there is a fundamental problem that is difficult to apply to a large area, and there is a difficulty in using a huge device called a radiation accelerator as a light source.

LIL, which is widely used to form repetitive patterns such as gratings, is easy to apply to large areas, relatively unaffected by the characteristics of the substrate, and has a low process cost, but requires a variety of patterns. It is difficult to apply, and it is impossible to use due to the overlay accuracy problem in the process of forming multiple layers.

On the other hand, a method of manufacturing a pattern in an imprint form using a mold is classified into a thermal method and an UV method, and is applicable to representative semiconductor substrates such as silicon (Si). Not only can it be possible, it can be easily applied not only to a plastic substrate requiring a low temperature process but also to a glass or quartz substrate having no conductivity.

The recent development of nanoimprint process technology makes it easier to control process pressure or temperature than conventional hot embossing lithography, and in the case of UV, it is possible to form patterns at room temperature and atmospheric pressure.

In the UV process, a transparent substrate or a mold is required, and quartz is typically used. However, a technique for forming a large pattern of 100 nm or less on a mold such as a quartz substrate is very demanding, and thus, a manufacturing cost is very high.

Accordingly, the technical problem to be achieved by the present invention is to provide a nano-imprint mold manufacturing method that can be formed while forming a fine pattern of 100nm or less, the process is easy and large.

Another object of the present invention is to provide a method for manufacturing a nanoimprint mold in which a pattern of 100 nm or more is formed simultaneously with a fine pattern of 100 nm or less.

In order to achieve the above technical problem, the present invention comprises the steps of forming a fine pattern on the first substrate through E-beam lithography (E-beam lithography); And transferring a fine pattern of the first substrate to a second substrate for a mold through a nanoimprint lithography (NIL) process to complete a NIL mold. .

According to an embodiment of the present invention, the forming of the fine pattern may include forming a pattern of 100 nm or more on the first substrate through the photolithography process.

The pattern of 100 nm or less uses an E-beam resist formed on the substrate, and the pattern of 100 nm or more uses a photoresist, wherein the E-beam register and the photoresist have respective exposure and It is preferable to use materials which are not affected by the developer.

Meanwhile, according to an embodiment of the present invention, the first substrate may be a silicon (Si) substrate that is easy to perform an E-beam lithography process, and the second substrate may be glass or quartz suitable for the NIL process. ) May be a substrate. Preferably, the second substrate is a quartz substrate.

In accordance with another aspect of the present invention, there is provided a method for forming an E-beam resist pattern through an E-beam lithography process and applying an E-beam resist to a first substrate. Forming a photo resist (PR) pattern on the first substrate on which the resist pattern is formed through a photo-lithography process; And transferring the E-beam resist pattern and the PR pattern of the first substrate to a second substrate for a mold through a nanoimprint lithography (NIL) process to complete a NIL mold (mold). Provided is a method for producing a mold.

According to one embodiment of the invention, the E-beam resist pattern is formed to 100nm or less, the PR pattern is preferably formed to 100nm or more. Accordingly, in the step of completing the NIL mold, 100 nm or less pattern is transferred to the second substrate using the E-beam resist pattern, 100 nm or less pattern is transferred using the PR pattern, and 100 nm or less. The NIL mold in which the above pattern was formed simultaneously can be formed.

On the other hand, in order to accurately adjust the position of the E-beam pattern and the PR pattern, it is preferable to include the step of forming an alignment key (align key) on the first substrate before the step of forming the E-beam resist pattern .

The nanoimprint mold according to the present invention has an advantage of forming an NIL mold in which not only a fine pattern of 100 nm or less but also a large pattern of 100 nm or more are simultaneously formed by using an E-beam lithography and photolithography process.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention; In the following description, when a component is described as being on top of another component, it may be directly on top of another component, and a third component may be interposed therebetween. In addition, the thickness or size of each component in the drawings are omitted or exaggerated for convenience and clarity of description, the same reference numerals in the drawings refer to the same elements. On the other hand, the terms used are used only for the purpose of illustrating the present invention and are not used to limit the scope of the invention described in the meaning or claims.

1 is a flowchart schematically illustrating a nanoimprint mold fabrication method of the present invention, and relates to a nanoimprint mold fabrication method in which a fine pattern of 100 nm or less and a pattern of 100 nm or more are formed together.

Referring to FIG. 1, first, an alignment key process is performed on a first substrate (S100). The align key process is performed for precise alignment of the later formed E-beam pattern with the photoresist (PR) pattern. The alignment key process is performed by applying PR to a first substrate, forming a PR pattern through a photolithography process, and then forming an alignment key through a dry etching process.

Thereafter, an E-beam resist pattern is formed through an E-beam lithography (EBL) process (S200). The EBL process refers to a process of applying an E-beam resist to a first substrate to expose and develop with a developer. Therefore, the first substrate is preferably a substrate made of a material that is easy to EBL process, such as a silicon substrate. At this time, the formed E-beam resist pattern is 100 nm or less.

Next, a PR pattern is formed through a photolithography process (S300). The PR pattern is formed by applying PR onto the E-beam resist pattern, followed by an exposure and development process, and the size of the pattern is 100 nm or more, generally about several μm.

In the E-beam lithography (EBL) process and the photolithography process, the E-beam resist and PR are applied by spin-coating, and the two resists are preferably not affected by each other by the respective exposure and development processes. Do.

After the PR pattern is formed, a pattern is formed on the first substrate through an etching process using the E-beam resist pattern and the PR pattern as an etch stop mask (S400). At this time, the pattern formed on the first substrate is simultaneously formed with a pattern of 100 nm or less by the E-beam resist pattern and a pattern of 100 nm or more by the PR pattern.

When the pattern is formed on the first substrate, a nanoimprint lithography (NIL) process is performed (S500). The NIL process applies a NIL resist to a second substrate, and then transfers the pattern of the first substrate into an imprint through a thermal or ultraviolet (UV) method to form a pattern in the NIL resist.

Thereafter, the NIL mold is completed by forming a pattern on the second substrate through an etching process using the NIL resist pattern as a mask (S600). Since the completed NIL mold is used as a mold for transferring a fine pattern through a NIL process to a device requiring a fine pattern of another 100 nm or less, the second substrate is a material that is easy to process a NIL process, particularly a UV NIL process. Substrates are preferred, and quartz substrates are generally preferred.

 The nanoimprint mold fabrication method of the present invention can easily fabricate a nanoimprint mold by using a first substrate having an easy E-beam process for forming a fine pattern, and also employs a photolithography process to provide 100 nm or more. The pattern also has the advantage of manufacturing a nanoimprint mold formed together.

2A to 2F are cross-sectional views illustrating a method for fabricating a nanoimprint mold according to a first embodiment of the present invention.

Referring to FIG. 2A, first, an E-beam resist 200 for an E-beam lithography process is applied to the first substrate 100. The first substrate 100 is preferably a substrate made of an easy E-beam lithography process. In this embodiment, a silicon (Si) substrate is used. The E-beam resist 200 may be formed of a single layer of hydrogen silsesquioxane (HSQ) by spin coating.

The thickness of the E-beam resist 200 can be controlled by adjusting the concentration of the HSQ and the spin coating rate. The solvent is preferably methyl isobutyl ketone (MIBK). In this embodiment, using a FQ (flowable oxide (FOX)) as the HSQ, to form an HSQ thin film of about 100nm thickness under spin coating conditions of 5000 rpm and 30 seconds.

Referring to FIG. 2B, the E-beam resist 200 is exposed to an E-beam and developed to form an E-beam resist pattern 200a. It is preferable to perform a prebaking process at 150 ° C. and 220 ° C. for 2 minutes before exposure, and the exposure is irradiated with e-beam at 100 kV and 100 pA conditions. The E-beam resist region where the pattern is not formed is removed using an aqueous TMAH-based developer. TMAH here means Tetramethylammonium hydroxide. The E-beam resist pattern 200a formed at this time is a fine pattern of 100 nm or less.

Referring to FIG. 2C, the first substrate 100 is dry-etched using the E-beam resist pattern 200a as an etch stop mask to form a first substrate 100a having a fine pattern.

Referring to FIG. 2D, the NIL resist 600 is coated on the second substrate 500, and the NIL process is performed after bonding the first substrate 100a having the pattern formed thereon. There is a thermal method that applies heat and pressure and a UV method that irradiates ultraviolet rays. In the case of the UV method, the process can be performed at room temperature and pressure.

The NIL resist 600 generally uses a polymer-based resin. In the case of the UV method, it is preferable to use a UV-curable polymer. As the coating method of the NIL resist 600, various methods such as spin coating, droplet dispensing, and spray may be used, but spin coating is preferable.

On the other hand, since the second substrate 500 is used as a mold for the NIL process of the device requiring a subsequent fine pattern, that is, a pattern of 100 nm or less, a substrate made of a material suitable for the NIL process is required. Substrates, such as quartz, glass, sapphire or diamond, through which ultraviolet light is transmitted, can be used, and a quartz substrate is preferable.

Referring to FIG. 2E, after completion of the NIL process, the first substrate 100a is separated to form the NIL resist pattern 600a.

Referring to FIG. 2F, a NIL mold 500a having a fine pattern is formed through dry etching using the NIL resist pattern 600a as an etch stop mask. At this time, the pattern formed is a fine pattern of 100 nm or less as described above.

In this embodiment, the E-beam lithography and NIL process are performed using a silicon substrate which is easy to e-beam lithography process in the production of a quartz NIL mold having no conductivity and difficult to form a fine pattern because the E-beam lithography process is difficult. Thereby, a quartz NIL mold can be manufactured easily.

3A to 3G are cross-sectional views illustrating a method for fabricating a nanoimprint mold according to a second embodiment of the present invention. Hereinafter, for the convenience of description, the same process as in the first embodiment will be omitted or briefly described.

Referring to FIG. 3A, first, an alignment key 120 is formed on the first substrate 100b. The alignment key 120 is generally formed through a photolithography process and an etching process, and then for alignment of the E-beam pattern and the PR pattern. Thus, alignment keys for the E-beam resist pattern and the PR pattern are simultaneously formed.

Referring to FIG. 3B, an E-beam resist pattern 200a is formed through an E-beam lithography process. The method of forming the E-beam resist pattern 200a is the same as in the first embodiment.

Referring to FIG. 3C, the PR 300 is coated on the entire surface of the first substrate 100b on which the E-beam resist pattern 200a is formed. The PR 300 is formed to form a large pattern such as a pad or an interconnect through a photolithography process. As described above, the PR 300 should be made of a resist that does not affect the E-beam resist during the exposure and development process, and the thickness thereof is preferably formed thicker than that of the E-beam resist pattern 200a.

Referring to FIG. 3D, a photolithography process is performed to form a large pattern PR pattern 300a.

Referring to FIG. 3E, dry etching is performed using the E-beam resist pattern 200a and the PR pattern 300a as an etch stop mask to form a first substrate 100c having a fine pattern and a large pattern. Therefore, a fine pattern of 100 nm or less and a large pattern of 100 nm or more, for example, several μm or more, are simultaneously formed on the first substrate 100c.

As shown in FIG. 3F, the NIL process 500 is formed by bonding the first substrate 100c to the second substrate 500 on which the NIL resist 600 is formed and performing the NIL process. To form.

As described in the first embodiment, in the present embodiment, the first substrate and the second substrate should also select a substrate of a suitable material. In particular, in the case of the first substrate, a substrate capable of both an E-beam lithography and a photo lithography process may be selected. It is preferable. In addition, it is preferable to select an appropriate material, a formation method, and the like for the E-beam resist, the PR, and the NIL resist.

In this embodiment, the E-beam lithography and photolithography process is performed using a first substrate capable of both E-beam lithography and photolithography processes, and transferred to the second substrate, thereby not only a fine pattern of 100 nm or less, but also 100 nm or more. A NIL mold in which a large pattern is formed at the same time can be produced.

4A is an atomic force microscope (AFM) photograph of a silicon mold manufactured according to a first embodiment of the present invention, and a two-dimensional graph thereof.

Referring to FIG. 4A, it can be seen from the left photograph that the fine patterns are three-dimensionally formed on the silicon substrate. The formed fine pattern can be seen that the aspect ratio of the height and width is about 2: 1 and the width of the pattern is about 50nm / 50nm through the right graph. On the other hand, the upper picture on the right is a two-dimensional AFM picture looking at the x-y plane.

4B are two-dimensional and three-dimensional AFM images of a silicon mold according to a second embodiment of the present invention.

Referring to FIG. 4B, the left picture is a two-dimensional picture and the right picture is a three-dimensional picture. In the picture, the white part is a patterned part, and the wide white part is a part in which a plurality of fine patterns are formed.

FIG. 5A is an AFM photograph of a quartz NIL mold formed through a NIL process using the silicon mold of FIG. 4A and a two-dimensional graph thereof. Referring to FIG. 5A, the pattern of the silicon substrate of FIG. 4A may be transferred to the quartz NIL mold to identify a quartz NIL mold having a fine pattern formed thereon.

FIG. 5B is an AFM photograph and a two-dimensional graph of a quartz NIL mold having a large pattern on the order of several μm. Referring to FIG. 5B, a part in which a large pattern is formed, that is, a pattern formed in a size of about several μm can be seen. In the picture on the left, the rectangular shape of the two parts is etched downward and the pattern is formed.

5C is a two-dimensional optical photograph of a quartz NIL mold using a silicon mold having the same pattern as that of FIG. 4B according to a second embodiment of the present invention. Referring to FIG. 5C, a quartz NIL mold having the same pattern as that of FIG. 4B is illustrated by using the silicon mold of the pattern manufactured according to the second embodiment. In the photograph, many long rectangular portions in the form of bands are formed in a large pattern, and a dark long band-shaped portion in the middle is a portion in which a fine pattern is formed.

The NIL mold fabrication method according to the present invention makes it easier to fabricate NIL molds required to implement nanoelectronics of 100 nm or less on a variety of substrates. As it can be actively utilized not only in the silicon semiconductor field but also in organic materials and bio fields, the ripple effect in related fields is expected to be huge.

So far, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. will be. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described in detail so far, the NIL mold fabrication method according to the present invention manufactures a quartz NIL mold using a mold such as a silicon substrate that is easy to e-beam, thereby making it easy and inexpensive to form a NIL mold having a fine pattern of 100 nm or less. Can be made.

In addition, by forming a large pattern of several μm on the silicon substrate together and transferred to the NIL mold by using a photolithography process, it is possible to produce a NIL mold in which a fine pattern of 100 nm or less and a large pattern of several μm are simultaneously formed.

As a result, the NIL process, which can form a sub-100nm ultrafine pattern on a large-area surface of various materials, is easier than the conventional EBL, FIBL, or DUV (or EUV) lithography technology. By making it easy, it can be actively utilized not only in the current silicon semiconductor field but also in the organic material and bio field, which is difficult to apply existing technology.

Claims (16)

Forming a pattern on the first substrate through an E-beam lithography process; And And transferring the pattern of the first substrate to a second substrate for a mold through a nanoimprint lithography (NIL) process to complete an NIL mold. According to claim 1, Forming a pattern on the first substrate, Applying an E-beam resist to the first substrate and forming an E-beam resist pattern through an E-beam lithography process; Forming a photo resist (PR) pattern on the first substrate on which the E-beam resist pattern is formed through a photo-lithography process; And And forming a pattern on the first substrate by using the E-beam resist pattern and the PR pattern of the first substrate. The method of claim 2, Through the E-beam lithography process to form a pattern of less than 100nm, Nanoimprint mold manufacturing method characterized in that to form a pattern of 100nm or more through the photolithography process. The method of claim 2, In order to precisely adjust the position of the E-beam pattern and the PR pattern, And forming an align key on the first substrate before the forming of the E-beam resist pattern. The method of claim 4, wherein The alignment key is formed on the first substrate through a photolithography process, A method for fabricating a nanoimprint mold, comprising simultaneously forming an E-beam alignment mark and a photo alignment mark. The method of claim 2, Wherein said E-beam register and photoresist are not affected by each exposure and developer. The method of claim 6, The E-beam resist is a nanoimprint mold manufacturing method, characterized in that formed of hydrogen silsesquioxane (HSQ). The method of claim 7, wherein Forming the E-beam resist is a nano-imprint mold manufacturing method, characterized in that formed by spin-coating (spin-coating) method. The method of claim 8, The E-beam resist is nanoimprint mold manufacturing method characterized in that the coating is carried out for 30 seconds at a speed of 5000 rpm to 100nm thickness. The method of claim 8, The E-beam resist pattern was prebaked at 150 ° C. and 200 ° C. for 2 minutes before exposure and irradiated with E-beam at 100 kV and 100 pA conditions, respectively. A method for fabricating a nanoimprint mold, comprising removing an unnecessary E-beam resist region with a developer. The method of claim 10, The developer is an aqueous TMAH-based developer, characterized in that the nanoimprint mold manufacturing method. According to claim 1, The first substrate is a silicon (Si) substrate, characterized in that the nanoimprint mold manufacturing method. According to claim 1, And the second substrate is a glass or quartz substrate. According to claim 1, The NIL process is a method of manufacturing a nanoimprint mold, characterized in that using a thermal (thermal) or ultraviolet (UV) method. According to claim 1, The NIL mold is a nanoimprint mold manufacturing method, characterized in that used in the pattern formation of the device requiring a fine pattern of 100 nm or less through the NIL process. The method of claim 15, The first substrate is a silicon substrate and the second substrate is a quartz substrate, The NIL process is a nanoimprint mold manufacturing method, characterized in that using a thermal method.

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