Imprint device

Abstract

An imprint device according to the present invention is provided with a supply device that supplies a plurality of condensable gases, which have different saturated vapor pressures, at a fixed ratio by a first condensable gas tank (6) and a control valve (6a) and a second condensable gas tank (6) and a control valve (7a) when a concave portion formed in a mold is transferred in an atmosphere of a condensable gas, which condenses at a temperature and a pressure in the concave portion, the concave portion being sealed by a resist layer that enters into the concave portion formed in the mold (3). The imprint device makes it possible to prevent resist filling failure caused by capillary condensation and to adjust pattern line width and shape by using the same mold.

Claims

1. An imprint device adapted to transfer a concave portion, which is formed in a mold, in an atmosphere of a condensable gas that condenses at a temperature and a pressure in the concave portion, the concave portion being sealed by a resist layer that enters into the concave portion formed in the mold, the imprint device comprising: a supply unit that supplies a plurality of condensable gases having different saturated vapor pressures at a fixed ratio as the condensable gas, wherein the plurality of condensable gases having different saturated vapor pressures include a first condensable gas, the saturated vapor pressure of which at normal temperature is 0.05 MPa or more and below 0.2 MPa, and a second condensable gas, the saturated vapor pressure of which at normal temperature is 0.2 MPa or more and 1 MPa or less, and the first condensable gas includes at least trans-1-chloro-3,3,3-trifluoropropene, and the second condensable gas includes at least trans-1,3,3,3-tetrafluoropropene.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a graph illustrating the diameter of a hole pattern that leads to capillary condensation for each condensable gas having a different saturated vapor pressure;

(2) FIG. 2 is a graph illustrating the ratio between a first condensable gas (trans-1-chloro-3,3,3-trifluoropropene gas) and a second condensable gas (trans-1,3,3,3-tetrafluoropropene) versus the diameter of a hole pattern that leads to the capillary condensation;

(3) FIG. 3 is a diagram illustrating the outline of a nano imprint device according to an embodiment;

(4) FIG. 4 is an electron microscope image of a pattern formed on a photocurable resin 2 on a substrate 1 by transferring a mold structure, in which each linear groove has a 70-nm width and a 100-nm depth, in an atmosphere of the first condensable gas 50% and the second condensable gas 50%;

(5) FIG. 5 is an electron microscope image of a pattern formed on the photocurable resin 2 on the substrate 1 by transferring a mold structure, in which each linear groove has a 125-nm width and a 100-nm depth, in an atmosphere of the first condensable gas 50% and the second condensable gas 50%;

(6) FIG. 6 is a graph illustrating the line width of the pattern formed by transferring the mold structure, in which each linear groove has the 70-nm width and the 100-nm depth, in atmospheres of different mixing conditions of the first condensable gas and the second condensable gas; and

(7) FIG. 7 is a graph illustrating the line width of the pattern formed by transferring the mold structure, in which each linear groove has the 125-nm width and the 100-nm depth, in atmospheres of different mixing conditions of the first condensable gas and the second condensable gas.

DESCRIPTION OF EMBODIMENTS

(8) The following will describe an embodiment with reference to the accompanying drawings.

EXAMPLE

(9) The present example will enable excellent imprint with high transfer accuracy by mixing a condensable gas having a low saturated vapor pressure and a condensable gas having a high saturated vapor pressure thereby to generate a condensation reaction over an entire area without being affected by the capillary condensation.

(10) To be specific, the pattern dimensions that lead to the capillary condensation when mixing the first condensable gas and the second condensable gas having different saturated vapor pressures as described above can be determined by the calculation according to expression (1).

(11) The influence rate of the capillary condensation can be approximately determined according to expression (3) given below by simply adding the influences of the first condensable gas and the second condensable gas on the basis of partial pressure, assuming that the two condensable gases have been mutually diluted.

(12) $\begin{array}{cc}a-2V_1{}_1\cos /\mathrm{RT}\ln \left(\frac{p_1}{p_{01}}\right)+-2V_2{}_2\cos /\mathrm{RT}\ln \left(\frac{p_2}{p_{02}}\right)& \left(3\right)\end{array}$

(13) where

(14) p.sub.01: Saturated vapor pressure of the first condensable gas

(15) p.sub.02: Saturated vapor pressure of the second condensable gas

(16) p.sub.1: Partial pressure of the first condensable gas

(17) p.sub.2: Partial pressure of the second condensable gas

(18) V.sub.1: Liquid molar volume of the first condensable gas (m.sup.3/mol)

(19) V.sub.2: Liquid molar volume of the second condensable gas (m.sup.3/mol)

(20) .sub.1: Liquid surface tension of the first condensable gas (N/m)

(21) .sub.2: Liquid surface tension of the second condensable gas (N/m)

(22) : Contact angle

(23) R: Gas constant (8.31 m.sup.2kg/s.sup.2Kmol)

(24) T: Temperature 293.15K (20 C.)

(25) a: Radius of capillary tube (m)

(26) FIG. 2 is a graph illustrating the ratio of mixed gas versus the diameter of a hole pattern that leads to the occurrence of the capillary condensation when mixing, for example, trans-1-chloro-3,3,3-trifluoropropene (the saturated vapor pressure at 20 C. being 0.107 MPa) as the first condensable gas and trans-1,3,3,3-tetrafluoropropene (the saturated vapor pressure at 20 C. being 0.419 MPa) as the second condensable gas.

(27) In this case, in order to apply the present method for a pattern dimensions ranging from 5 nm to a few hundred nm to which the nano imprint is expected to be applied, the nano imprint should be carried out under a condition in which the ratio of the second condensable gas with respect to the first condensable gas is 35% or more. At this ratio, the diameter of a hole pattern leading to the occurrence of the capillary condensation is 5 nm or less.

(28) FIG. 3 is a diagram illustrating the outline of a nano imprint device according to the present embodiment.

(29) The imprint device presses a mold 3, which has a fine pattern formed thereon, against the photocurable resin 2, which has been formed in a molten state on the substrate 1. Holding the mold 3 and the photocurable resin 2 in contact with each other, the photocurable resin 2 is hardened thereby to transfer the pattern onto the substrate 1.

(30) The imprint device described above is used to manufacture, for example, semiconductor devices and microsensors.

(31) As the substrate 1, silicon or glass, for example, is used. As the mold 3, glass, transparent resin, or the like is used. The film of the photocurable resin 2 is formed on the substrate 1 by, but not limited to, a spin coater, a dispenser, an inkjet, a bar coater, an applicator, and a spray coater.

(32) The photocurable resin 2 is acryl-based, epoxy-based, silicone-based or phenol-based, but not limited thereto insofar as the resin is a photocurable resin composition.

(33) The imprint transfer method is, for example, a method in which patterns are transferred in one operation by using the mold 3 having a pattern of approximately the same size as a substrate, a step-and-repeat method in which a pattern is transferred in a plurality of times by using a mold having a pattern that is smaller than a substrate, or a roll method in which patterns are consecutively transferred by using a cylindrical mold; however, the imprint transfer method is not limited thereto insofar as the transfer method uses a mold or a die.

(34) Nozzles 4a and 4b are installed in a space formed between the substrate 1 and the mold 3. Through a condensable gas supply pipe 5, the first condensable gas and the second condensable gas are supplied at a fixed ratio from a first condensable gas tank 6 and a second condensable gas tank 7 through control valves 6a and 7a, respectively.

(35) Thus, the method in which a plurality of condensable gases are supplied into the space formed between the substrate 1 and the mold 3 makes it extremely easy to create an environment of a highly concentrated mixed gas; however, the method is not limited thereto insofar as a method makes it possible to create a mixed atmosphere between the substrate 1 and the mold 3, such as a method in which a closed space is created for each imprint space, such as a chamber.

(36) To be specific, first, PAK-01 (made by TOYO GOSEI), which is a UV-curable resin was spin-coated to a film thickness of 80 nm on a 4-inch silicon substrate. As the mold, a 10 mm-square quartz mold (NIM-PHL45 made by NTT-AT) was used. Further, a step-and-repeat type nano imprint device was used.

(37) The imprint conditions were 0.1-MPa applied pressure, 10-second pressurization time, 100-mJ/cm.sup.2 UV irradiation intensity, and 1-second irradiation time. Trans-1-chloro-3,3,3-trifluoropropene, the saturated vapor pressure at 20 C. of which is 0.107 MPa, was used as the first condensable gas, and trans-1,3,3,3-tetrafluoropropene, the saturated vapor pressure at 20 C. of which is 0.419 MPa, was used as the second condensable gas.

(38) The nano imprint was carried out five times, during which the ratio between the first condensable gas and the second condensable gas was changed by 25% while setting the flow rates of the first condensable gas and the second condensable gas by the control valves 6a and 7a such that the total of the flow rates of these two gases is maintained to be 2000 sccm.

(39) The first condensable gas was 100% and the second condensable gas was 0% for the first nano imprint, the first condensable gas was 75% and the second condensable gas was 25% for the second nano imprint, the first condensable gas was 50% and the second condensable gas was 50% for the third nano imprint, the first condensable gas was 25% and the second condensable gas was 75% for the fourth nano imprint, and the first condensable gas was 0% and the second condensable gas was 100% for the fifth nano imprint.

(40) However, in every nano imprint, small amounts of inevitable components, such as nitrogen and oxygen, are contained.

(41) The shapes of the patterns formed by the imprint were observed under an electron microscope (FE-SEM). Thereafter, based on acquired image files, two line patterns were extracted, and the average line width of the patterns was calculated by using a line width determination program.

(42) FIG. 4 and FIG. 5 illustrate the electron microscope images of the patterns transferred by imprint onto the photocurable resin 2 on the substrate 1 in the atmosphere of the first condensable gas of 50% and the second condensable gas of 50%.

(43) FIG. 4 illustrates the pattern obtained by transferring a mold structure of linear grooves, each of which has a 70-nm width and a 100-nm depth, and FIG. 5 illustrates the pattern obtained by transferring a mold structure of linear grooves, each of which has a 125-nm width and a 100-nm depth. The patterns illustrated in both figures have been successfully formed, being free of pattern defects, such as bubble defects.

(44) FIG. 6 is a graph illustrating the line width of the pattern formed by transferring the mold structure, in which each linear groove has the 70-nm width and the 100-nm depth, in atmospheres of different mixing conditions of the first condensable gas and the second condensable gas.

(45) When the proportion of the second condensable gas was 0% (i.e. when the first condensable gas was 100%), the line width of the imprinted pattern was the smallest. Conversely, when the proportion of the second condensable gas was 100% (i.e. when the first condensable gas was 0%), the line width of the imprinted pattern was the largest.

(46) At a medium ratio, it was verified that the line width varies with high linearity, depending on the proportion of the second condensable gas. This indicates that the line width of a pattern that can be formed can be freely controlled by adjusting the ratio of mixed gases.

(47) FIG. 7 is a graph illustrating the line width of the pattern formed by transferring the mold structure, in which each linear groove has the 125-nm width and the 100-nm depth, in atmospheres of different mixing conditions of the first condensable gas and the second condensable gas. As with the above case, it could be verified that the line width varies with high linearity, depending on the proportion of the second condensable gas.

REFERENCE SIGNS LIST

(48) 1: Substrate 2: Photocurable resin 3: Mold 4a, 4b: Nozzle 5: Condensable gas supply pipe 6: First condensable gas tank 7: Second condensable gas tank 6a, 7a: Control valve