JP4935312B2 - Imprint mold and imprint mold manufacturing method - Google Patents

Description

  The present invention relates to an imprint mold for forming an uneven pattern.

  In recent years, a pattern transfer technique called an imprint method has been proposed as a method for forming a fine pattern (Non-Patent Document 1). As typical imprint methods, there are mainly a thermal imprint method and an optical imprint method.

<Thermal imprint method>
Hereinafter, an example of the thermal imprint method will be described.
First, a mold 110 made of metal having unevenness is formed (FIG. 1A).
Next, a resin layer 112 is formed by applying a resin material such as PMMA on the transfer substrate 111 on which a pattern is to be formed (FIG. 1B).
Next, the transfer substrate 111 on which the resin layer 112 is formed is heated to about 120 to 200 ° C. to soften the resin layer 112.
Next, the mold 110 and the transfer substrate 111 are overlaid so that the uneven surface side of the mold faces the coated surface side of the resin layer 112 of the transfer substrate 111 and brought into contact with a pressure of about 3 to 20 MPa (FIG. 1 (c). )).
Next, with the mold 110 in contact with the transfer substrate 111, the temperature is lowered to about 100 ° C. or less to cure the resin layer 112, and the mold is peeled off.
As described above, a pattern corresponding to the uneven pattern of the mold 110 is formed on the resin layer 112 on the transfer substrate 111 (FIG. 1D).
Further, since a portion corresponding to the convex portion of the mold 110 remains as a thin residual film on the transfer substrate 111, the residual film may be removed by O ₂ RIE (reactive ion etching using oxygen gas) or the like. (FIG. 1 (e)).

<Optical imprint method>
Hereinafter, an example of the optical imprint method will be shown (see Patent Document 1).
First, a mold 120 having a concavo-convex shape on the surface is manufactured by electron beam lithography or the like and etching a substrate made of a light-transmitting material such as quartz (FIG. 2A).
Next, a resin 122 that is a liquid photocurable resin composition having a low viscosity is applied onto the transfer substrate 121 (FIG. 2B).
Next, the mold 120 is brought into contact with the resin 122 (pressing pressure is about 0.01 to 5 MPa), and light is irradiated from the back surface of the mold 120 to cure the resin 122. (FIG. 2 (c)).
As described above, a pattern corresponding to the concave / convex pattern of the mold 120 is formed on the resin layer 122 on the transfer substrate 121 (FIG. 2D).
Further, since a portion corresponding to the convex portion of the mold 120 remains as a thin residual film on the transfer substrate 121, the residual film may be removed by O ₂ RIE (reactive ion etching using oxygen gas) or the like. (FIG. 2 (e)).
JP 2000-194142 A Appl. phys. Lett. , Vol. 67, p3314 (1995)

  Due to the principle of the imprint method, the imprint mold used in the imprint method is in physical contact with the transfer substrate on which the pattern is transferred via the pattern material (FIG. 1 (c), FIG. 2 (c)). ).

  In the concavo-convex pattern formed in the imprint mold, when the pattern portion has a sparse / dense bias (FIGS. 3A and 4A), the amount of pattern material filled in the sparse and dense regions is different. When the imprint mold comes into contact with the transfer substrate, the imprint mold may be inclined (FIGS. 3B and 4B).

At this time, if the imprint method is performed in an inclined state, the distribution of the remaining film is biased (FIG. 3C). The uneven distribution of the residual film causes a problem that when the residual film is removed by the O ₂ RIE method, the transfer pattern is etched at the same time, so that the height of the transfer pattern cannot be controlled.

  Further, the load concentrates on the pattern portion of the imprint mold that first contacts the substrate, and the pattern portion of the imprint mold may be destroyed (FIG. 4C). The destroyed pattern portion cannot be accurately transferred to the substrate, but also becomes a foreign matter or a defect due to a fragment of the imprint mold. Further, since the imprint mold itself becomes a pattern defect, it cannot be used continuously for imprinting.

  The present invention has been made to solve the above-described problems, and provides an imprint mold that prevents the imprint mold and the transfer substrate from being inclined when the imprint mold and the transfer substrate are pressure-bonded in the imprint method. Objective.

The present invention, in an imprint mold for forming an uneven pattern,
The substrate is provided with an uneven pattern area,
When the auxiliary pattern having a recess outside the uneven pattern region on the surface where the uneven pattern is formed divides the substrate into arbitrary sections, the recess of the uneven pattern and the volume of the auxiliary pattern recess or The imprint mold is characterized in that the total area is constant .
In the imprint mold for forming a concavo-convex pattern according to the present invention, the total volume or area of the concave portion of the concavo-convex pattern and the concave portion of the auxiliary pattern in the one partition It is an imprint mold characterized by being equal to the sum of the volume or area of the concave portion of the concave / convex pattern and the concave portion of the auxiliary pattern.
Here, the concavo-convex pattern is not limited to a rectangular groove pattern, and is a pattern having a step having an arbitrary shape. The uneven pattern includes a multi-stage pattern.

  In the imprint mold manufacturing method for forming a concavo-convex pattern, the present invention according to claim 2 includes a step of dividing the substrate into arbitrary sections, and a step of measuring the volume of the concave portions in the concavo-convex pattern area in the sections. And measuring the volume of the recesses in the auxiliary pattern so that the volumes of the recesses in the compartments are the same amount, and forming the uneven pattern region and the auxiliary pattern on the substrate. It is the imprint mold manufacturing method characterized by performing.

  The present invention described in claim 3 is the imprint mold manufacturing method according to claim 2, wherein the step of dividing the substrate into arbitrary partitions is a step of dividing the substrate into partitions each having the same amount of area. It is the imprint mold manufacturing method characterized by this.

  The imprint mold of the present invention is characterized in that an auxiliary pattern is provided outside the concavo-convex pattern region, and the pattern material filled in the partition by uniformizing the distribution of the sparse region and the dense region of the pattern portion Can be made uniform. For this reason, in the imprint method, when the imprint mold and the transfer substrate are pressure-bonded, it is possible to prevent the both from being inclined.

Hereinafter, the imprint mold of the present invention will be described.
The imprint mold of the present invention is
The substrate is provided with an uneven pattern area,
An auxiliary pattern is provided outside the uneven pattern region on the surface on which the uneven pattern is formed.

  The imprint mold of the present invention is not limited to a specific imprint method, and can be widely applied to known imprint methods. Specific examples include imprint methods such as optical imprint, thermal imprint, and sol-gel imprint.

  The substrate can be appropriately selected so as to be suitable for the imprint method to be used. Examples thereof include silicon and quartz glass.

  Further, the uneven pattern can be designed according to the pattern to be transferred to the transfer substrate, and the step is not limited to one step and may be a multi-stepped shape.

  The auxiliary pattern is a pattern having concave portions, and is provided to make the distribution of the sparse and dense regions of the concave portions uniform. The auxiliary pattern is formed outside the concavo-convex pattern region. The shape of the auxiliary pattern can be changed according to the concavo-convex pattern, and can be appropriately designed so as to be within each section.

  Hereinafter, the imprint mold manufacturing method of the present invention will be described.

<Step of dividing the substrate into arbitrary sections>
First, the substrate is divided into arbitrary sections. The number of divisions and the division method are design matters, and can be changed according to the degree of difficulty in calculating the concave / convex pattern transferred to the transfer substrate and the auxiliary pattern described later.
At this time, in order to make the distribution of the sparse area and the dense area of the pattern portion uniform over the entire surface of the substrate, it is preferable that the divided sections have the same amount of area.

<Step of measuring the volume of the recess in the uneven pattern area>
<Step of measuring the volume of the recess in the auxiliary pattern>
Next, the volume of the recess in the auxiliary pattern in each section is determined according to the volume of the recess in the uneven pattern region.
At this time, it is assumed that the sum of the volumes satisfying the concave portions of the concave / convex pattern and the concave portions of the auxiliary pattern in one section is equal to the sum of the volumes satisfying the concave portions of the concave / convex pattern and the auxiliary pattern of each divided section.
Thereby, in the imprint method, the pattern material necessary for filling becomes equal in each section, and when the imprint mold and the transfer substrate are pressure-bonded, both can be prevented from being inclined.
For this reason, it is possible to give a uniform residual film distribution in pattern formation by the imprint method, prevent pattern destruction of the imprint mold, and accurately transfer the pattern. Moreover, since the thickness of the remaining film is uniform, a desired pattern can be obtained even if the remaining film is removed by the RIE method or the like.

  Moreover, when the depth of the recessed part in an uneven | corrugated pattern and an auxiliary pattern is the same, you may determine an auxiliary pattern using the area of a pattern part instead of a volume. Thereby, the difficulty of measurement can be lowered.

  Moreover, it is preferable that the sum of the volumes filling the concave portions of the concave and convex patterns and the concave portions of the auxiliary patterns in each section is equal to the section having the largest volume of the concave portions of the concave and convex patterns. Thereby, consumption of pattern material can be suppressed.

<Process for forming uneven pattern region and auxiliary pattern>
Next, an uneven pattern region and an auxiliary pattern are formed.
As a method for forming the concavo-convex pattern and the auxiliary pattern on the substrate, a publicly known method can be used as appropriate, and a material suitable for the substrate material and the assumed imprint method can be used. For example, you may form by using together a lithography technique and an etching technique.

  As mentioned above, the imprint mold manufacturing method of this invention can be implemented.

  Hereinafter, an example of implementation of the imprint mold manufacturing method of the present invention will be described with reference to FIGS. Of course, the present invention is not limited to the following examples.

<Example 1>
An imprint mold for carrying out the optical imprint method is manufactured. The concavo-convex pattern formed on the transfer substrate was an LS, Dot, and Hole pattern with an opening size of 100 nm.

  First, the substrate is divided into each section. In the present example, as shown in FIG. 5, it was divided into four sections (section A, section B, section C, section D) by straight lines intersecting at the center of gravity of the substrate.

Next, the volume of the concave portion of the concave / convex pattern region in the compartment is measured. In this example, since the depth of the concave portion of the concave / convex pattern is constant at 100 nm, the area was measured.
Each area, compartment A is 4.0 cm ^2, partition B is 5.0 cm ^2, partition C is 3.2 cm ^2, partition D was 4.8 cm ^2,.

Next, the volume of the concave portion of the auxiliary pattern is determined for each section. In this example, since the depth of the concave portion of the concave / convex pattern is constant at 100 nm, the area was measured.
Area of the recess of the auxiliary pattern, each section A is 4.0 cm ^2, partition B is 3.0 cm ^2, partition C is 4.8 cm ^2, the compartment D was 3.2 cm ^2.

  The pattern portion to be formed on the substrate was determined so that the auxiliary pattern having the above-described area fits in each section.

<Example 2>
The pattern part determined in Example 1 was formed on a quartz substrate.

A method for manufacturing the mold is shown in FIG. A 6025 size photomask substrate having a thickness of Cr of 100 nm and a resist of 400 nm was used as a base substrate for the mold (FIG. 6B). With the electron beam drawing apparatus, the pattern portion determined in Example 1 was drawn, and a resist pattern was formed by organic development (FIG. 6C). The conditions at this time were a drawing dose of 100 μC / cm ² and a development time of 2 minutes.

Next, a Cr pattern was formed by Cr etching using an ICP dry etching apparatus and O ₂ plasma ashing using a barrel ashing apparatus (FIG. 6D). The Cr etching conditions were Cl ₂ flow rate 20 sccm, O ₂ flow rate 10 sccm, He flow rate 30 sccm, pressure 3 Pa, ICP power 500 W, RIE power 50 W, etching time 40 seconds, and O ₂ plasma ashing conditions were O ₂ flow rate 500 sccm, pressure The power was 30 Pa and the RF power was 1000 W.

Next, by using an ICP dry etching apparatus, the quartz substrate was etched using the patterned Cr layer as an etching mask to form a concavo-convex pattern (FIG. 6E). At this time, the quartz etching conditions were a C ₄ F ₈ flow rate of 10 sccm, an O ₂ flow rate of 10 to 25 sccm, an Ar flow rate of 75 sccm, a pressure of 1 to ₂ Pa, an ICP power of 200 W, an RIE power of 550 W, and an etching time of 90 seconds.

  Next, wet peeling cleaning of the Cr layer was performed (FIG. 6 (f)), an uneven pattern and an auxiliary pattern provided outside the uneven pattern region were formed, and an imprint mold was manufactured.

<Example 3>
The optical imprint method was performed using the imprint mold created in Example 2.

  First, the concavo-convex pattern surface of the quartz mold 170 shown in FIG. 7A was previously coated with a fluorine-based surface treatment agent EGC-1720 (Sumitomo 3M) as a release agent.

  Next, as shown in FIG. 7B, a substrate to be imprinted was coated on a silicon substrate 171 as a resin 172 with a photocurable resin (Toyo Gosei Co., Ltd., PAK-01) with a thickness of 300 nm.

Next, as shown in FIG. 7C, the quartz mold 170 was brought into contact with the resin 172, and light was irradiated from the back surface of the quartz mold 170 to cure the resin 172. The conditions for optical imprinting were as follows: no pre-baking (room temperature), pressing pressure 2 MPa, UV wavelength 365 nm, UV exposure 40 mJ / cm ² .

Next, as shown in FIG. 7D, the remaining film of the resin 172 onto which the pattern of the quartz mold 170 was transferred was removed by the O ₂ RIE method. Thereby, as shown in FIG.7 (e), the resin pattern was obtained.

  The mold pattern after imprinting and the formed resin pattern were observed with a scanning electron microscope. The mold pattern and the formed resin pattern were not destroyed, and a good pattern shape was observed. It was also confirmed that the height of the formed pattern portion was uniform.

  The imprint mold of the present invention is useful in a wide range of fields for forming fine concavo-convex patterns, such as semiconductor devices, optical components, recording devices such as hard disks and DVDs, biochips such as DNA analysis, diffusion plates and light guides. It can be expected to be suitably used for pattern formation required in the production of displays such as plates and MEMS devices.

It is sectional process drawing which shows the pattern formation by a thermal imprint method. It is sectional process drawing which shows pattern formation by the optical imprint method. It is a figure which shows a mode that the imprint mold is imprinted on the transfer board | substrate and a residual film becomes non-uniform | heterogenous. It is a figure which shows a mode that an imprint mold is imprinted on the transfer board | substrate and an imprint mold is destroyed. It is a front view which shows an example of the imprint mold of this invention. 6 is a cross-sectional view showing a manufacturing process of a quartz mold for optical imprinting in Example 2. FIG. 10 is a cross-sectional view showing a pattern forming process by an optical imprint method in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 110 ... Mold 111 ... Transfer substrate 112 ... Resin 120 ... Quartz mold 121 ... Transfer substrate 122 ... Resin 130 ... Mold 131 ... Transfer substrate 132 ... Resin 140 ... Mold 141 ... Transfer substrate 142 ... Resin 143 ... Pattern destruction part 150 ... Mold 151 ... Auxiliary pattern 152 ... Uneven pattern 160 ... Quartz substrate 161 ... Chrome 162 ... Resist 170 ... Quartz mold 171 ... Transfer substrate 172 ... Resin

Claims (4)

In the imprint mold for forming the uneven pattern,
The substrate is provided with an uneven pattern area,
When the auxiliary pattern having a recess outside the uneven pattern region on the surface where the uneven pattern is formed divides the substrate into arbitrary sections, the recess of the uneven pattern and the volume of the auxiliary pattern recess or An imprint mold characterized by being provided so that the total area is constant . In the imprint mold for forming the uneven pattern,
The sum of the volume or area of the concave portion of the concave / convex pattern and the concave portion of the auxiliary pattern in the one partition is equal to the sum of the volume or area of the concave portion of the concave / convex pattern and the concave portion of the auxiliary pattern in each divided partition. The imprint mold according to claim 1, wherein: In the imprint mold manufacturing method for forming the uneven pattern,
Dividing the substrate into arbitrary sections;
Measuring the volume of the recess in the uneven pattern area in the compartment;
Measuring the volume of the concave portion in the auxiliary pattern so that the volume of the concave portion between the compartments is the same amount,
The imprint mold manufacturing method characterized by performing the process of forming the said uneven | corrugated pattern area | region and the said auxiliary pattern in the said board | substrate. The imprint mold manufacturing method according to claim 2,
The method of manufacturing an imprint mold, wherein the step of dividing the substrate into arbitrary partitions is a step of dividing the substrate into partitions each having the same amount of area.

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