KR101885793B1 - Master mold having fine scale pattern and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a master mold having a fine pattern and a manufacturing method thereof. A master mold according to the present invention comprises: a substrate; A first metal layer applied over the entire surface of the substrate; A second metal layer applied over the entire surface of the first metal layer; A burying region of the pattern on the surface of the second metal layer exposes the second metal layer; a third metal layer formed on the intaglio region of the pattern; And a fourth metal layer extending from the surface of the second metal exposed to the relief region to a vertical upper portion so as to have a higher height than the third metal layer. Since the master mold according to the present invention has the sidewalls of the pattern formed as vertical walls and the cross section of the pattern has a rectangular shape, a critical dimension of a fine line width of several hundreds of nanometers can be secured.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a master mold having a fine pattern,

The present invention relates to a master mold having a fine pattern and a manufacturing method thereof. More particularly, the present invention relates to a master mold used for forming a line grating or stripe pattern having a fine line width of several hundred nanometers by a transfer method and a manufacturing method thereof.

Generally, in order to produce a substrate having a line grid or a stripe pattern, it is common to form a pattern directly on a substrate using a photolithography technique. In particular, when it is necessary to repeatedly produce patterns of the same size, it is possible to form the same fine pattern with an extremely small error range by using an imprinting process using a secondary mold made of a master mold.

However, when a master mold to be used for the imprinting method is manufactured, it is limited to form a fine pattern when manufactured by a subtractive process using a photolithography technique. FIGS. 1A to 1D are cross-sectional views illustrating a method of manufacturing a master mold by a subtractive process using a photolithography technique according to the prior art.

A buffer layer BUF is formed on the substrate SUB. A metal layer (ME) is applied on the buffer layer (BUF). A photoresist layer (PR) is applied on the surface of the metal layer (ME). (Fig. 1A)

And aligns the mask MA corresponding to the line grating or the stripe pattern on the substrate SUB to which the photoresist layer PR is applied. In the mask MA, the hatched portion is a blocking portion through which light can not pass, and the hatched portion represents an opening through which light passes. Exposure is performed by irradiating ultraviolet rays (UV) toward the photoresist layer PR from above the mask MA. Then, the state of the photoresist layer (PR) corresponding to the opening through which light passes and the state of the photoresist layer (PR) corresponding to the blocking portion through which light does not pass are different. For example, in the case of using a positive photoresist, the photoresist layer PR corresponding to the opening passing through the light is broken, and the photoresist layer PR corresponding to the blocking portion maintains the connectivity. In order to distinguish the photoresist layer PR corresponding to the opening portion of the mask MA from the photoresist layer PR corresponding to the blocking portion, the photoresist layer PR corresponding to the blocking portion is indicated by hatching. (Fig. 1B)

The substrate SUB having the photoresist layer PR exposed through the exposure process is developed. As a result, the photoresist PR corresponding to the opening portion is removed by the developing solution because the bonding property is destroyed by ultraviolet (UV), and only the photoresist layer PR corresponding to the blocking portion remains on the metal layer ME. (Fig. 1C)

The metal layer (ME) is etched using the photoresist layer (PR) formed in a line or stripe pattern. Then, when the photoresist layer PR is removed, a metal layer ME having a line grid or a stripe pattern is formed. (Figure 1d)

Thus, a secondary mold to be used in the imprinting process is manufactured by using a master mold having a line grating or a stripe pattern, and a final patterned substrate is manufactured by imprinting using a secondary mold. Although the final pattern substrate can be manufactured by using the master mold, when the master mold is repeatedly used several times, the size and shape of the final pattern substrates are deformed due to wear and deformation, so that uniformity of quality can not be ensured.

Therefore, when a final product is manufactured using a secondary mold by using a secondary mold, and when the reproducibility of the secondary mold is lowered, a secondary mold is produced again with the master mold to produce a final product. Uniformity can be ensured. In the imprinting process, the master mold production method is most important in order to ensure the uniformity of product quality and the reproducibility of production.

As described above, the pattern of the master mold formed by the method of manufacturing by the subtractive process has a short upper end section and a lower end cross section. That is, as shown in FIG. 2, which is an enlarged cross-sectional view of a patterned metal layer according to the prior art, it is common that the cross section of the patterned photoresist layer PR has a trapezoidal shape. 2, the dashed line represents a profile in which the metal layer (ME) is etched. As the etching proceeds, the metal layer ME is not only removed in the thickness direction, but also undercuts occur in the lateral direction, that is, the lower portion of the photoresist layer PR. Since the pattern is formed in such a trapezoid, there is a limit to how much the width of the pattern can be finely formed. That is, since the sidewalls of the patterned metal layer ME do not form a perfect vertical wall, when a fine pattern is formed, it directly affects a critical dimension (CD) of the line width of the pattern. Due to such a problem, there is a problem in forming a master mold having a minute pattern of several hundred nanometers in the prior art.

There are a number of proposed techniques for producing master molds for imprinting processes. For example, there are methods disclosed in Japanese Patent Application Laid-Open Nos. 11-251722, 4-260389, 11-266069, and 11-266070, but a specific practical method for forming a fine pattern is proposed I can not.

JP 2005-00288043 discloses a method of manufacturing a master mold for a fine pattern to be used in an imprinting process. However, since the master mold is manufactured in a complicated process and the firmness of the pattern of the master mold is not sufficiently secured, There is a problem in securing the reproducibility of manufacturing in a process of forming a plurality of secondary molds for producing a product.

It is an object of the present invention to provide a master mold having a fine pattern having vertical sidewalls reflecting the shape of a patterned photoresist layer and a method of manufacturing the master mold. Another object of the present invention is to provide a master mold having a simple manufacturing process, securing the rigidity of a pattern, and excellent manufacturing reproducibility, and a manufacturing method thereof.

A master mold according to the present invention comprises: a substrate; A first metal layer applied over the entire surface of the substrate; A second metal layer applied over the entire surface of the first metal layer; A burying region of the pattern on the surface of the second metal layer exposes the second metal layer; a third metal layer formed on the intaglio region of the pattern; And a fourth metal layer extending from the surface of the second metal exposed to the relief region to a vertical upper portion so as to have a higher height than the third metal layer.

And the cross-sectional shape of the fourth metal layer formed in the relief region is a rectangular shape having substantially the same length as the length of the upper surface.

Wherein the first metal layer and the third metal layer comprise a first metal material; And the second metal layer and the fourth metal layer include a second metal material having an excellent bonding property with the first metal material.

The first metallic material comprises chromium; And the second metallic material comprises nickel.

In addition, a method of manufacturing a master mold according to the present invention includes sequentially applying a first metal layer, a second metal layer, and a third metal layer on a substrate; Forming a photoresist layer on the third metal layer and patterning the photoresist layer with a mask; Patterning the third metal layer using the patterned photoresist layer as a mask; Applying a fourth metal layer above the surface of the third metal layer on the surface of the second metal layer exposed between the surface of the patterned photoresist layer and the patterned third metal layer; And removing the patterned photoresist layer.

Depositing the first metal layer, the second metal layer and the third metal layer to have the same thickness; Wherein the photoresist layer has a thickness greater than that of the third metal layer; And the fourth metal layer is deposited to have a height between the upper surface of the third metal layer and the upper surface of the photoresist layer.

And the fourth metal layer is deposited to have a height between 25% and 75% between the upper surface of the third metal layer and the upper surface of the photoresist layer.

Wherein the first metal layer and the third metal layer comprise a first metal material; And the second metal layer and the fourth metal layer include a second metal material having an excellent bonding property with the first metal material.

The first metallic material comprises chromium; And the second metallic material comprises nickel.

In the master mold according to the present invention, the side wall of the pattern is formed as a vertical wall, and the cross section of the pattern has a rectangular shape. Accordingly, the present invention provides a master mold having a pattern width of several hundred nanometer units. Further, the master mold according to the present invention has a cross-sectional structure formed by continuously depositing the same metal material. Therefore, it is possible to ensure the uniformity of the product and the reproducibility of production at the time of producing the secondary mold with repetition, because the pattern is robust. In the method of manufacturing a master mold according to the present invention, a fine pattern having vertical sidewalls is formed by using a photoresist layer patterned to have a vertical wall, so that the manufacturing process of the master mold is simple.

FIGS. 1A to 1D are cross-sectional views illustrating a method of manufacturing a master mold in a subtractive process using a photolithography technique according to the prior art,
2 is a cross-sectional view of a patterned section of a metal layer in a master mold according to the prior art,
3A to 3F are cross-sectional views illustrating a method of manufacturing a master mold according to the present invention.
4 is an enlarged cross-sectional view of a patterned section of a metal layer in a master mold according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 3A to 3F and FIG. 3A to 3F are cross-sectional views illustrating a method of manufacturing a master mold according to the present invention. 4 is an enlarged cross-sectional view of a patterned section of a metal layer in a master mold according to the present invention.

A first metal layer (M1) is coated on the entire surface of the substrate (SUB). The first metal layer Ml also serves as a buffer layer. Subsequently, the second metal layer M2 and the third metal layer M3 are sequentially coated on the first metal layer M1. For example, the first metal layer M1 includes a metal material having good characteristics as a buffer layer and having anisotropic arousal, such as chromium, and the thickness thereof is deposited to a thickness of about 1 mu m. The second metal layer M2 has excellent abrasion resistance and includes a metal material such as nickel, which is excellent in the metal binding force at the time of vapor deposition. The thickness of the second metal layer M2 is about 1 μm. The third metal layer M3 is deposited with the same metal material as the first metal layer M1 to have the same thickness. That is, the third metal layer M3 includes chromium and has a thickness of about 1 mu m. A photoresist layer (PR) is entirely coated on the third metal layer (M3). At this time, the thickness of the photoresist layer PR is important. In the present invention, since the fine pattern is formed on the master mold by using the photoresist layer PR, the thickness of the photoresist layer PR is preferably thicker than the thickness of the third metal layer M3. For example, the thickness of the photoresist layer PR is preferably at least 2 탆 or more. (Fig. 3A)

And aligns the mask MA corresponding to the line grating or the stripe pattern on the substrate SUB to which the photoresist layer PR is applied. In the mask MA, the hatched portion is a blocking portion through which light can not pass, and the hatched portion represents an opening through which light passes. An exposure process for irradiating ultraviolet rays (UV) toward the photoresist layer PR is performed from the top of the mask MA. Then, the state of the photoresist layer (PR) corresponding to the opening through which light passes and the state of the photoresist layer (PR) corresponding to the blocking portion through which light does not pass are different. For example, in the case of using a positive type photoresist, the photoresist layer PR corresponding to the opening through which light passes is broken, and the photoresist layer PR corresponding to the blocking portion maintains the connectivity. In order to distinguish the photoresist layer PR corresponding to the opening portion of the mask MA from the photoresist layer PR corresponding to the blocking portion, the photoresist layer PR corresponding to the blocking portion is indicated by hatching. (Figure 3b)

A development process is performed with a substrate SUB having a photoresist layer PR exposed through an exposure process. Then, the photoresist layer PR corresponding to the opening portion is removed by the developing solution because the bonding property is destroyed by ultraviolet (UV), and only the photoresist layer PR corresponding to the blocking portion remains on the third metal layer M3 . That is, it has the same shape as the relief region of the pattern of the photoresist layer PR. (Figure 3c)

The third metal layer M3 is etched using the photoresist layer PR formed in a line or stripe pattern. Then, the third metal layer M3, which is the same as the pattern of the photoresist layer PR, also has a line grating or stripe pattern. That is, the photoresist layer PR and the third metal layer M3 become a relief region of the pattern, and the second metal layer M2 is exposed to a portion corresponding to the relief region of the pattern. (Fig. 3d)

The fourth metal layer M4 is deposited on the entire surface of the substrate SUB in the state that the photoresist layer PR having the same pattern remains on the third metal layer M3 having the stripe pattern or the stripe pattern. Then, the fourth metal layer M4 is applied to the upper surface of the photoresist layer PR corresponding to the embossed area of the pattern. At the same time, the fourth metal layer M4 is also coated on the exposed second metal layer M2 corresponding to the intaglio region of the pattern. At this time, the coating thickness of the fourth metal layer M4 is very important, and it should be thicker than the thickness of the third metal layer M3. In particular, the thickness of the applied fourth metal layer M4 from the upper surface of the third metal layer M3 to the upper surface of the fourth metal layer M4 corresponds to the thickness of the final pattern of the final master mold. The thickness of the fourth metal layer M4 should be such that the upper surface of the fourth metal layer M4 is located lower than the upper surface of the photoresist layer PR. That is, it is preferable that the upper surface of the fourth metal layer M4 be deposited to a position between 25% and 75% between the upper surface of the third metal layer M3 and the upper surface of the photoresist layer PR. For example, if the third metal layer M3 has a thickness of 1 mu m and the photoresist layer PR has a thickness of 2 mu m, then the thickness of the fourth metal layer M4 is greater than 1 mu m and less than 3 mu m desirable. In this case, the fourth metal layer M4 is preferably deposited to a thickness of about 1.5 to 2.5 mu m. In particular, the thickness of the fourth metal layer M4 is preferably determined according to the thickness of the embossed area of the final pattern of the master mold. For example, if the difference in thickness between the embossed area and the intaglio area of the final pattern of the master mold is 0.5 mu m, it is preferable that the fourth metal layer M4 has a thickness of 1.5 mu m. As another example, if the difference in thickness between the embossed area and the intaglio area of the final pattern of the master mold is to be 1 mu m, it is preferable that the fourth metal layer M4 has a thickness of 2 mu m. (Fig. 3E)

After depositing the fourth metal layer M4, the photoresist layer PR is peeled off. Then, the photoresist layer PR is removed, and the fourth metal layer M4 applied on the photoresist layer PR is also peeled off. However, the fourth metal layer M4 deposited on the second metal layer M2 exposed in the intaglio region of the pattern remains. As a result, a pattern of the master mold is finally formed on the substrate SUB. At this time, the final pattern of the master mold is a pattern in which the fourth metal layer M4 is a relief area and the third metal layer M3 is a depressed area, which is opposite to the pattern when the photoresist layer PR is patterned. Particularly, the fourth metal layer M4 is deposited on the surface of the second metal layer M2, and is grown by penetrating the third metal layer M3 from the second metal layer M2. If the degree of coupling between the fourth metal layer M4 and the second metal layer M2 is excellent, the pattern of the master mold can ensure the rigidity. Therefore, it is preferable that the fourth metal layer M4 uses the same nickel as the second metal layer M2. (Figure 3f)

Referring to FIG. 4, the specific shapes and features of the patterns of the master mold will be described in more detail. The master mold according to the present invention comprises a substrate SUB, a first metal layer M1 serving as a buffer deposited on the entire surface of the substrate SUB, a base metal layer M1 on the first metal layer M1, A third metal layer M3 formed on the second metal layer M2 in a reverse pattern of the final pattern and a second metal layer M2 formed on the second metal layer M2, And a fourth metal layer (M4) extending from the surface of the metal layer (M2) and extending vertically to form a bony pattern region to form a final pattern.

The photoresist layer (PR) is patterned by ultraviolet curing. Thus, the pattern of the photoresist layer PR can be patterned to have vertical sidewalls. However, when the third metal layer M3 is etched using the photoresist layer PR as a mask, the undercut phenomenon is also performed on the lower side surface of the photoresist layer PR It happens. Even if the third metal layer M3 is made of a material having anisotropic etching, etching from the bottom of the photoresist layer PR toward the sidewall can not be prevented originally.

In the present invention, since the pattern of the master mold is not formed by the third metal layer (M3) undercut, even if the undercut phenomenon occurs in the third metal layer (M3), it does not become a big problem. That is, when the fourth metal layer M4 is formed on the exposed surface of the second metal layer M2 while the third metal layer M3 is patterned and the photoresist layer PR having the vertical sidewall is formed up to a certain height, The side wall of the metal layer M4 may be formed in the shape of a vertical wall. At this time, a cavity portion formed by the undercut at the lower portion of the photoresist layer PR may be filled with the metal material of the fourth metal layer M4 while being deposited. Particularly, in selecting the metal material of the third metal layer (M3) and the metal material of the second metal layer (M2) and the fourth metal layer (M4), it is preferable to select a metal material having similar characteristics and excellent in metal- desirable. In the present invention, chromium and nickel are selected and used to obtain the best results.

As a result, the pattern of the master mold, which is between the upper surface of the third metal layer M3 and the upper surface of the fourth metal layer M4, has a shape in which the sidewall, which is the boundary between the relief region and the intaglio region, is nearly perfectly vertical. That is, the pattern formed on the master mold according to the present invention has a rectangular or square shape in which the cross-sectional shape of the embossed area is the same in length between the upper surface and the lower surface. Therefore, even when a pattern having a fine line width of several hundreds of nanometers is formed, it is possible to form a fine pattern with a critical dimension of the line width up to the nanometer scale.

In producing the master mold according to the present invention, the two layers formed on the substrate (SUB) were formed by selecting two types of metal layers having excellent bonding properties. Also, one of the two metal layers was selected and used without using a separate material for the buffer layer. Therefore, there is an additional advantage that the material selection and the manufacturing process are simple.

In the present invention, since the embossed area of the photoresist layer PR is formed as the intaglio area of the master mold, the master mold according to the present invention has a pattern which is opposite to the pattern of the mask MA. The master mold formed by the present invention can be used to prepare a secondary mold for use in the imprinting process. At this time, the secondary mold has a pattern which is opposite to that of the master mold. And, when the final pattern substrate is fabricated with the secondary mold, the final product has a pattern that is opposite to the pattern of the secondary mold. That is, the final product is formed in a pattern having the same phase as the master mold.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

SUB: Substrate BUF: Buffer layer
ME: metal layer PR: photoresist layer
MA: mask UV: ultraviolet
M1: first metal layer M2: second metal layer
M3: third metal layer M4: fourth metal layer

Claims (9)

Board;
A first metal layer applied over the entire surface of the substrate;
A second metal layer applied over the entire surface of the first metal layer;
A burying region of the pattern on the surface of the second metal layer exposes the second metal layer; a third metal layer formed on the intaglio region of the pattern; And
And a fourth metal layer formed on the surface of the second metal exposed to the relief region so as to extend vertically above the third metal layer.
The method according to claim 1,
Wherein the cross-sectional shape of the fourth metal layer formed in the relief region is a rectangular shape having the same length as the length of the upper surface.
delete The method according to claim 1,
Wherein the first metal layer and the third metal layer comprise chromium;
Wherein the second metal layer and the fourth metal layer comprise nickel.
Sequentially applying a first metal layer, a second metal layer and a third metal layer on a substrate;
Forming a photoresist layer on the third metal layer and patterning the photoresist layer with a mask;
Patterning the third metal layer using the patterned photoresist layer as a mask;
Applying a fourth metal layer above the surface of the third metal layer on the surface of the second metal layer exposed between the surface of the patterned photoresist layer and the patterned third metal layer;
And removing the patterned photoresist layer. ≪ RTI ID = 0.0 > 11. < / RTI >
6. The method of claim 5,
Depositing the first metal layer, the second metal layer and the third metal layer to have the same thickness;
Wherein the photoresist layer has a thickness greater than that of the third metal layer;
Wherein the fourth metal layer is deposited to have a height between an upper surface of the third metal layer and an upper surface of the photoresist layer.
The method according to claim 6,
Wherein the fourth metal layer is deposited to have a height between 25% and 75% between the upper surface of the third metal layer and the upper surface of the photoresist layer.
delete 6. The method of claim 5,
Wherein the first metal layer and the third metal layer comprise chromium;
Wherein the second metal layer and the fourth metal layer comprise nickel.

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