JP2016058735A - Imprint device, imprint method and manufacturing method of article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imprint device that is advantageous for aligning a substrate and a mold.SOLUTION: The imprint device is configured to form a pattern on the substrate by aligning the mold and the substrate and curing an imprint material while bringing the mold into contact with the imprint material on the substrate. The imprint device includes: a light radiation part for radiating light that cures the imprint material; and means for irradiating the imprint material with light of which the wavelength band or the intensity is different from the light of the light radiation part and which improves viscosity of the imprint material. The alignment is performed on the substrate where the imprint material is irradiated with the light that improves the viscosity of the imprint material.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an imprint apparatus, an imprint method, and an article manufacturing method.

  The demand for miniaturization of semiconductor devices, MEMS, and the like has progressed, and development of an imprint technique for forming an uncured resin on a substrate with a mold and forming a resin pattern on the substrate is progressing. By using the imprint technique, a fine structure of nanometer order can be formed on the substrate.

  One of the imprint techniques is a photocuring method. In the imprint method by this photocuring method, first, an uncured photocurable resin (imprint material) is supplied onto a substrate (wafer). Next, the resin on the substrate is brought into contact with the mold (an imprinting process). And resin is hardened by irradiating light (ultraviolet rays) in the state where resin and a mold were made to contact (curing process). After the resin is cured, by expanding the distance between the substrate and the mold (mold release step), the mold is separated from the cured resin, and a resin pattern is formed on the substrate.

  In the imprint apparatus, the position of the pattern (substrate side pattern) formed in advance on the substrate and the position of the pattern (mold pattern portion) formed on the mold in a state where the resin and the mold are in contact with each other. It is necessary to match.

  In order to match the position of the substrate side pattern with the position of the mold pattern portion, the positional deviation between the two marks is obtained by detecting the alignment mark formed on the mold and the alignment mark formed on the substrate. The deviation is corrected (Patent Document 1).

  In Patent Document 1, the exposure time for curing the resin on the substrate is divided into a plurality of portions so that the exposure is performed intermittently, and the amount of positional deviation between the substrate and the mold is obtained by the alignment detection system during the non-exposure period. By aligning the substrate side pattern and the mold pattern portion based on the amount of displacement, the displacement that occurs during exposure for curing the resin is reduced.

JP 2013-168504 A

  On the other hand, in order to quickly fill the pattern (uneven portions) formed in the mold with resin, it has been proposed to imprint using a resin with low viscoelasticity or in a condensable gas atmosphere. ing. The latter method is also effective in reducing the viscoelasticity of the resin.

  However, if the viscoelasticity is lowered, the shearing force of the resin becomes lower, so when aligning the substrate and the mold, it is easy to receive disturbances such as vibration from the floor where the imprint apparatus is installed, and the alignment accuracy is lowered. End up.

  The present invention has been made in view of such a situation, and an object thereof is to provide an imprint apparatus that is advantageous for alignment of a substrate and a mold.

  In the imprint apparatus of the present invention, in a state where the mold is in contact with the imprint material on the substrate, the pattern is formed on the substrate by aligning the mold and the substrate and curing the imprint material. In the imprint apparatus to be formed, a light irradiation unit that irradiates light for curing the imprint material, and the light of the light irradiation unit is light having a different wavelength band or intensity, and the light of the imprint material Means for irradiating the imprint material with light that enhances viscoelasticity, and performing alignment with the substrate irradiated with light that enhances the viscoelasticity of the imprint material. Features.

  In addition, the imprint apparatus according to another aspect of the present invention is configured to align the mold and the substrate and cure the imprint material in a state where the mold is in contact with the imprint material on the substrate. An imprint apparatus that forms a pattern on the substrate, and includes a light irradiation unit that irradiates light to the imprint material, and a control unit that controls the imprint apparatus, By increasing the viscoelasticity of the imprint material by irradiating the imprint material with the light irradiation section, the magnitude of the shear force of the imprint material generated by the relative movement of the substrate and the mold is 0.1N. As described above, the position of the mold and the substrate irradiated with light that enhances the viscoelasticity of the imprint material by the light irradiation unit is adjusted to be 10 N or less, And light irradiating the imprint material by serial light irradiating unit, characterized in that curing the imprint material.

  ADVANTAGE OF THE INVENTION According to this invention, the imprint apparatus advantageous for position alignment of a board | substrate and a type | mold can be provided.

It is a figure which shows the structure of the imprint apparatus which concerns on 1st Embodiment. It is a figure which shows the structure and arrangement | positioning of the preliminary exposure means which concern on 1st Embodiment. It is a figure which shows the process of the imprint process which concerns on 1st Embodiment. It is a figure which shows the structure of the preliminary exposure means which concerns on 4th Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in each figure, the same reference number is attached | subjected about the same member and the overlapping description is abbreviate | omitted.

(First embodiment)
(About imprint equipment)
The imprint apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of an imprint apparatus 1 according to the first embodiment. The imprint apparatus 1 forms an uncured resin 14 (imprint material) on a wafer 10 (substrate) as a substrate to be processed using a mold 8 (mold) and forms a pattern of the resin 14 on the wafer 10. It is. This apparatus is an imprint apparatus employing a photocuring method in which a resin (ultraviolet curable resin) is cured by irradiation with light (ultraviolet light). In the following drawings, the Z axis is parallel to the optical axis of the illumination system for irradiating the resin 14 on the wafer 10 with ultraviolet rays 9, and the X axes are orthogonal to each other in a plane perpendicular to the Z axis (in the plane of the wafer 10). And Y axis.

  The imprint apparatus 1 includes a light irradiation unit 2, a mold holding mechanism 3, a wafer stage 4, a coating unit 5, a pre-exposure unit 6 (pre-exposure unit), and a control unit 7.

  The light irradiation unit 2 irradiates the resin 14 with ultraviolet rays 9 when the resin 14 on the wafer 10 is cured in the imprint process. Here, the ultraviolet rays 9 from the light irradiation unit 2 irradiate the resin 14 through (transmitting) the mold 8. The light irradiation unit 2 includes a light source (not shown) and an optical element (lens, mirror, light shielding plate) that adjusts the ultraviolet light 9 emitted from the light source to a light state (light intensity distribution, illumination area, etc.) suitable for imprinting. Etc.).

  The mold holding mechanism 3 includes a mold chuck 11 that holds the mold 8, and a mold drive mechanism 12 that holds the mold chuck 11 and moves the mold 8 (mold chuck 11). The mold chuck 11 can hold the mold 8 by attracting the mold 8 by vacuum suction force or electrostatic force. For example, when the mold chuck 11 holds the mold 8 by a vacuum suction force, the mold chuck 11 is connected to a vacuum pump (not shown), and the detachment / attachment of the mold 8 is switched by turning on / off the vacuum pump.

  The mold 8 has a rectangular outer peripheral shape, and includes a pattern portion 8a in which a concave / convex pattern to be transferred such as a circuit pattern is formed in a three-dimensional manner on the surface of the mold 10. The material of the mold 8 is a material that can transmit light (ultraviolet rays 9) from the light irradiation unit 2, and in this embodiment, is made of quartz as an example. Further, in order to facilitate deformation as described later, the mold 8 has a shape in which a cavity (concave portion) having a circular shape and a certain depth is formed on the surface irradiated with the ultraviolet rays 9. It is good.

  Further, the mold chuck 11 and the mold driving mechanism 12 have an opening region 13 at the center (inside) so that the ultraviolet rays 9 irradiated from the light irradiation unit 2 are directed toward the wafer 10. In this opening region 13, a light transmitting member (for example, a glass plate) is installed in which a space surrounded by a part of the opening region 13 and the mold 8 is a sealed space, and a pressure adjusting device (not shown) including a vacuum pump is installed. The pressure in the enclosed space is adjusted. The pressure adjusting device, for example, sets the pressure in the sealed space higher than the outside when the pattern portion 8a of the mold 8 and the resin 14 on the wafer 10 are in contact with each other, so that the mold 8 protrudes toward the wafer 10. To bend. By bending the mold 8 into a convex shape, the resin 14 on the wafer 10 can be brought into contact with the center portion of the pattern portion 8a of the mold 8. Thereby, it can suppress that gas (air) remains between the pattern part 8a and the resin 14, and can fill the uneven part of the pattern part 8a with the resin 14 to every corner.

  The mold drive mechanism 12 moves the mold 8 in the Z-axis direction so that the mold 8 and the resin 14 on the wafer 10 are brought into contact with or separated from each other. As an actuator that can be employed in the mold drive mechanism 12, for example, there is a linear motor or an air cylinder. Further, the mold drive mechanism 12 may be composed of a plurality of drive systems such as a coarse drive system and a fine drive system in order to cope with high-precision positioning of the mold 8. Further, the mold driving mechanism 12 has a position adjusting function in the X-axis direction, the Y-axis direction, or the θ (rotation around the Z-axis) direction as well as the Z-axis direction, and a tilt function for correcting the tilt of the mold 8. You may be comprised from the drive system which has.

  The contact and separation operations in the imprint apparatus 1 may be realized by moving the mold 8 in the Z-axis direction, but may be realized by moving the wafer stage 4 in the Z-axis direction, or Both of them may be moved relatively.

  The wafer 10 is, for example, a single crystal silicon substrate or an SOI (Silicon on Insulator) substrate, and an ultraviolet curable resin is applied as a resin 14 to a surface to be processed on which a pattern is formed.

  The wafer stage 4 (substrate stage) holds the wafer 10 and moves in the wafer in-plane direction when the mold 8 and the resin 14 on the wafer 10 come into contact with each other, thereby aligning the mold 8 and the wafer 10. The wafer stage 4 includes a wafer chuck 16 that holds the wafer 10 by an attractive force, and a stage drive mechanism 17 that holds the wafer chuck 16 by mechanical means and is movable in each axial direction. Examples of actuators that can be used for the stage drive mechanism 17 include a linear motor and a planar motor. The stage drive mechanism 17 may also be composed of a plurality of drive systems such as a coarse drive system and a fine drive system in each direction of the X axis and the Y axis. Furthermore, there may be a configuration having a drive system for position adjustment in the Z-axis direction, a position adjustment function of the wafer 10 in the θ direction, or a tilt function for correcting the tilt of the wafer 10. Further, the wafer stage 4 includes a plurality of reference mirrors (reflecting portions) 18 corresponding to the X, Y, and Z directions on the side surface. Furthermore, a plurality of reference mirrors 18 corresponding to ωx, ωy, and ωz indicating rotation directions corresponding to the X, Y, and Z directions may be provided.

  The imprint apparatus 1 includes a laser interferometer 19 (position measurement means) for measuring the position of the wafer stage 4. The imprint apparatus 1 may include a plurality of laser interferometers 19 corresponding to the reference mirrors 18 described above. The laser interferometer 19 measures the position of the wafer stage 4 by irradiating each reference mirror with a beam. The laser interferometer 19 measures the position of the wafer stage 4 in real time, and the control unit 7 described later controls the positioning of the wafer 10 (wafer stage 4) based on the measured value at this time. Further, the imprint apparatus 1 may be provided with a laser interferometer 19 (position measuring means) for measuring the position of the mold holding mechanism 3. Note that the position of the wafer stage 4 and the mold holding mechanism 3 may not be measured by a laser interferometer, but a length measuring device such as a linear scale or a linear encoder may be used.

  The application unit 5 (dispenser) is installed in the imprint apparatus 1 and supplies (applies) uncured resin 14 to the surface to be processed of the wafer 10. The resin 14 as an imprint material is a photocurable resin having a property of being cured by light irradiation, and is appropriately selected according to various conditions such as a semiconductor device manufacturing process. The application unit 5 includes a discharge nozzle 5a through which uncured resin 14 is discharged. The amount and application position of the resin 14 discharged from the discharge nozzle 5a are appropriately determined depending on the thickness of the resin 14 formed on the wafer 10, the density of the pattern formed on the wafer 10, and the like.

  The pre-exposure means 6 irradiates the uncured resin 14 supplied on the wafer 10 with light having a sensitive wavelength (light having a wavelength at which the resin is cured). The resin 14 has high viscoelasticity when irradiated with light from the pre-exposure means 6.

  Since the viscoelasticity of the resin 14 supplied onto the wafer 10 is low, the resin 14 is easily filled into the pattern portion 8 a of the mold 8. Therefore, bubbles remaining in the pattern portion 8a can be reduced. However, if the resin 14 has low viscoelasticity, the position of the mold 8 and the wafer 10 may be displaced due to disturbance. If the resin 14 is cured in a state where the position of the mold 8 and the wafer 10 is displaced, the overlay accuracy is increased. Decreases.

  FIG. 2 is a diagram showing the configuration and arrangement of the pre-exposure means 6 provided in the imprint apparatus 1. In FIG. 2, the same components as those in FIG. In the first embodiment, the light source used in the pre-exposure means 6 is used in combination with the light source of the light irradiation unit 2 that is irradiated with light (ultraviolet rays 9) for curing the uncured resin 14. Here, the pre-exposure (pre-exposure) by the pre-exposure means 6 is performed after the resin 14 is supplied onto the wafer 10, the mold 8 and the resin 14 are brought into contact, and the resin 14 is cured by the ultraviolet rays 9. Is called. That is, the pre-exposure is performed when the mold 8 and the wafer 10 are aligned. The alignment of the mold 8 and the wafer 10 is performed by detecting an alignment mark corresponding to the pattern portion 8a formed on the mold and an alignment mark corresponding to the pattern 20 formed on the wafer 10. The pattern 20 includes a shot area in which a pattern is formed in advance on the wafer 10. That is, the alignment of the mold 8 and the wafer 10 is to overlap the pattern portion 8a and the shot area. The alignment of the mold 8 and the wafer 10 may include a step of changing the shape of the mold 8 (pattern part 8a).

  However, if the light (ultraviolet ray 9) irradiated from the light irradiation unit 2 is used as it is for the pre-exposure, the sensitivity of the light to the resin 14 is high, so that the alignment between the mold 8 and the wafer 10 is completed. The resin 14 may be cured.

  Therefore, the pre-exposure means 6 of the first embodiment includes an optical filter 21 (optical element) that reflects or absorbs light of a part of wavelengths included in the light irradiated from the light irradiation unit 2 to block (separate) the light. Have. Alternatively, the pre-exposure means 6 has an optical filter 21 that transmits light of a part of wavelengths included in the light irradiated from the light irradiation unit 2. Alternatively, the preliminary exposure unit 6 may combine an optical filter that blocks light from the light irradiation unit 2 and an optical filter that transmits the optical filter.

  Here, as the optical filter 21, an optical filter having a function of blocking light having a wavelength (first wavelength) with high sensitivity to the resin 14 among the light irradiated from the light irradiation unit 2 is used. For example, it is assumed that the main wavelength band of the ultraviolet ray 9 for curing (photosensitizing) the resin 14 is 200 to 400 nm. Among these, light having a wavelength (second wavelength) having low sensitivity with respect to the resin 14 exists in a wavelength band of 300 to 350 nm. Therefore, the optical filter 21 is an optical filter having a function of blocking light having a wavelength other than light of the second wavelength (wavelength band of 300 to 350 nm) included in the ultraviolet light 9. The optical filter 21 may be a filter having a function of transmitting light of the second wavelength and blocking light of other wavelengths.

  The optical filter 21 is installed on the optical path of the ultraviolet rays 9 from the light irradiation unit 2 toward the wafer 10 and between the light irradiation unit 2 and the mold 8. The operation of the optical filter 21 is controlled by the control unit 7. The optical filter 21 is movable in a plane direction (XY plane) orthogonal to the optical path (Z axis) of the ultraviolet light 9 irradiated from the light irradiation unit 2 by the drive mechanism 22. At the time of preliminary exposure, the optical filter 21 is placed in the optical path of the ultraviolet rays 9 as shown in FIG. On the other hand, when the resin 14 is cured and exposed, the optical filter 21 is retracted from the optical path of the ultraviolet light 9 as shown in FIG. In the pre-exposure means 6 of the first embodiment, any optical filter 21 that blocks or transmits light in a specific wavelength band among the light irradiated from the light irradiation unit 2 may be used. Therefore, the optical filter 21 may employ an interference filter or a beam splitter (dichroic mirror) having a wavelength dependency on the transmittance (or reflectance).

  The control unit 7 can control the operation and adjustment of each component of the imprint apparatus 1. The control unit 7 is configured by, for example, a computer, and is connected to each component of the imprint apparatus 1 via a line, and can control each component according to a program or the like. The control unit 7 of the present embodiment controls at least the operation of the preliminary exposure unit 6. The control unit 7 may be configured integrally with other parts of the imprint apparatus 1 (in a common casing), or separate from the other parts of the imprint apparatus 1 (in another casing). To).

  The imprint apparatus 1 also includes an alignment detection system 26 for measuring the shape or size of the pattern 20 on the wafer 10 during imprint processing. The alignment detection system 26 (alignment detection means) uses reflected light or diffracted light of the exposure light to detect the alignment detection system so that the detection accuracy does not deteriorate even when pre-exposure light or curing exposure light is incident. It is preferable to adopt a configuration that suppresses entry into H.26. Further, even if reflected light or diffracted light of preliminary exposure or curing exposure light enters the alignment detection system 26, the optical system may be configured so that the detection accuracy does not deteriorate. For example, an optical filter (optical element) that uses light having a wavelength different from that of the light for pre-exposure and curing exposure as a light source of the alignment detection system 26 and shields the light for pre-exposure and curing exposure in the alignment detection system 26. It may be incorporated. With this configuration, the alignment marks formed on the pattern 20 and the pattern portion 8a can be detected without degrading the detection accuracy of the alignment detection system 26 even during preliminary exposure or curing exposure. Can do. The imprint apparatus 1 can determine the positional deviation between the mold 8 and the wafer 10 from the detection result of the alignment mark, and can align the both.

  The imprint apparatus 1 also includes a base surface plate 27 on which the wafer stage 4 is placed, a bridge surface plate 28 that fixes the mold holding mechanism 3, and a base surface plate 27. And a support column 30 for supporting the bridge surface plate 28. The vibration isolator 29 removes vibration transmitted from the floor surface to the bridge surface plate 28. Further, although not shown, the imprint apparatus 1 includes a mold transport mechanism that transports the mold 8 from the outside of the apparatus to the mold holding mechanism 3, a substrate transport mechanism that transports the wafer 10 from the outside of the apparatus to the wafer stage 4, and the like. May be included.

(About imprint processing)
Next, an imprint process performed by the imprint apparatus 1 will be described with reference to FIG. First, the control unit 7 loads the wafer 10 by the substrate transfer mechanism, and places and fixes the wafer 10 on the wafer chuck 16 on the wafer stage 4. Next, the control unit 7 drives the stage driving mechanism 17 to move the pattern 20 (shot area) on the wafer 10 to a coating position by the coating unit 5. Next, the control part 7 makes the application part 5 apply the resin 14 on the pattern 20 (S1: application process). Next, the control unit 7 re-drives the stage driving mechanism 17 and moves the pattern 20 on the wafer 10 so that the pattern 20 is positioned directly below the pattern unit 8 a formed on the mold 8. Next, the controller 7 drives the mold drive mechanism 12 to bring the resin 14 on the wafer 10 into contact with the mold 8 (S2: stamping process). When the resin 14 and the mold 8 are in contact with each other, the resin 14 is filled in the uneven portion of the pattern portion 8a. In a state where the resin 14 and the mold 8 are in contact with each other, pre-exposure is performed using the pre-exposure means 6 in order to increase the viscoelasticity of the resin 14 (S3: pre-exposure step). With the viscoelasticity increased, the mold 8 and the wafer 10 are aligned (S4: alignment step). After the alignment, in a state where the resin 14 and the mold 8 are in contact with each other, the control unit 7 irradiates the light irradiation unit 2 with the ultraviolet rays 9 and cures the resin 14 with the ultraviolet rays 9 transmitted through the mold 8 (S5: Curing). Process). And the control part 7 re-drives the mold drive mechanism 12, and separates the mold 8 from the hardened resin 14 (S6: mold release process). As a result, a pattern (layer) of the three-dimensional resin 14 is formed (transferred) on the pattern 20 following the concavo-convex portion formed in the pattern portion 8a. By performing a series of such imprint processes (imprint operations) a plurality of times while changing the region of the pattern 20 by driving the wafer stage 4, a pattern of a plurality of resins 14 is formed on one wafer 10. (S7).

  Consider the magnitude of the shear force generated by the relative movement of the wafer 10 and the mold 8 in the alignment of the pattern 20 and the pattern portion 8a. When the pre-exposure means 6 is not used and the minimum value of the shearing force at the time of alignment between the pattern 20 and the pattern portion 8a is less than 0.1 N, the alignment between the pattern 20 and the pattern portion 8a is caused by disturbance from the floor or the like. Accuracy may be reduced.

  Therefore, the minimum value of the shearing force at the time of aligning the pattern 20 and the pattern portion 8a is set to 0.1 N or more, preferably 0.3 N or more, more preferably 0.5 N or more by the preliminary exposure by the preliminary exposure means 6. Further, the maximum value of the shearing force is set to 10 N or less, preferably 5 N or less, more preferably 1 N or less. On the other hand, when the shearing force exceeds 10 N, the pattern shape may be collapsed when the pattern 20 and the pattern portion 8a are aligned, resulting in a decrease in alignment accuracy. For example, as a result of evaluating the relationship between the viscosity of a resin having a thickness of several tens of nanometers and the shearing force, it is necessary to increase the viscosity coefficient in the order of 1000 N / (m / s) by 50% or more to obtain a predetermined shearing force. is there. As the viscosity coefficient, it is preferable that the minimum value is 10,000 N / (m / s) or more, and the maximum value is 1,000,000 N / (m / s) or less, more preferably 100,000 N / (m / s) or less. . As described above, by performing the pre-exposure so that the shearing force is equal to or less than the predetermined value, the alignment accuracy between the pattern 20 and the pattern portion 8a can be improved.

  Further, in order to predetermine the exposure amount by the pre-exposure means 6, the wafer stage 4 is driven under the stamped conditions, and the shear force is measured using the exposure amount in the case of pre-exposure and the pre-exposure as a parameter, You may obtain | require the exposure amount of the required preliminary exposure. In addition, the relationship between the exposure amount and the shearing force may be obtained with another apparatus to determine the exposure amount for the preliminary exposure. Further, the exposure amount of the preliminary exposure may be determined by measuring the viscosity such as the viscosity coefficient instead of the shearing force.

  Also, the pre-exposure means 6 irradiates the surface of the pattern 20 with pre-exposure light with a uniform intensity distribution, so that the viscoelastic characteristics in the pattern 20 do not become non-uniform, and the pattern 20 and the pattern portion 8a. When the alignment is performed, the shearing force of the resin 14 can be made uniform. As a result, it is possible to suppress the deterioration of the pattern shape accompanying the alignment.

(Other conditions)
In the first embodiment, the case where the wavelength of light used for preliminary exposure and the wavelength of light used for curing the resin are different using the same light source has been described. On the other hand, when the wavelength of light used for pre-exposure and the wavelength of light used for curing the resin are the same, the exposure amount of pre-exposure is 1/10 or less of the exposure amount necessary for curing, preferably 1/100 or less. More preferably, it is preferably set to 1/1000 or less. The required exposure amount depends on the sensitivity of the resin used. Thus, compared with the exposure amount required to cure the uncured resin 14, the exposure amount required to increase the viscoelasticity by the preliminary exposure is very small.

  Further, a light source having low sensitivity with respect to the uncured resin 14 can be used as the pre-exposure means 6. Therefore, you may comprise the light source of a 1st wavelength and a 2nd wavelength by a different light source. The viscoelasticity of the uncured resin 14 can be controlled by using a light source different from the light source (light irradiation unit 2) used for curing the resin. Further, the light from the light irradiation unit 2 may be reduced by the optical filter 21 so that the light used for the pre-exposure has an intensity (exposure amount) necessary for the pre-exposure.

  In the first embodiment, the pre-exposure is performed after the mold 8 and the resin 14 are brought into contact with each other, and after the pre-exposure is performed, the pattern 20 and the pattern portion 8a are aligned. The pre-exposure timing may be when the pattern 20 and the pattern portion 8a are aligned. Further, if the resin 14 is in a range that does not affect the filling property of the pattern portion 8a, pre-exposure may be performed after the resin 14 is applied on the wafer 10 and before the stamping process. Pre-exposure may be performed during the stamping process in which the resin 14 is brought into contact with the resin 14.

  As described above, according to the present embodiment, the viscoelasticity of the resin 14 is increased before the curing step during the imprint process. Therefore, it is possible to suppress the occurrence of misalignment between the mold 8 and the wafer 10 during the curing process, and to improve the overlay accuracy of the pattern 20 existing in advance on the wafer 10 and the newly formed resin 14 pattern. it can.

(Second Embodiment)
Next, the imprint apparatus 1 according to the second embodiment will be described. A feature of the imprint apparatus 1 according to the second embodiment is that it has vibration detection means for detecting the vibration of the wafer 10 or the mold 8 and performs pre-exposure until the output of the vibration detection means becomes a predetermined value or less. That is. Pre-exposure is performed until the output of the vibration detection means (for example, the amplitude of vibration) is 10 nm or less, preferably 5 nm or less, more preferably 1 nm or less. An alignment detection system 26 may be used as the vibration detection means. The alignment detection system 26 detects the vibration of the wafer 10 and the mold 8 by detecting the alignment marks formed on the pattern 20 on the wafer 10 and the pattern portion 8 a formed on the mold 8. The imprint apparatus 1 according to the second embodiment can detect relative vibration between the wafer 10 and the mold 8 from the obtained positional deviation amount.

  Further, the vibration of the wafer 10 may be detected by a laser interferometer 19 that measures the position of the wafer stage 4 as vibration detection means.

  Since the vibration of the wafer 10 or the mold 8 is detected by the vibration detecting means and the output of the detecting means is set to a predetermined value or less, the preliminary operation is performed after the stamping process and during the alignment of the pattern 20 and the pattern portion 8a. Perform exposure.

  Further, if the exposure amount in the pre-exposure increases too much, the pattern shape collapses when the pattern 20 and the pattern portion 8a are aligned as the shear force of the resin 14 increases, resulting in a decrease in alignment accuracy. is there. For this reason, it is preferable to perform the pre-exposure when the positional deviation amount between the pattern 20 and the pattern portion 8a is 100 nm or less, preferably 50 nm or less, more preferably 25 nm or less. After the preliminary exposure, after the amount of positional deviation between the pattern 20 and the pattern portion 8a becomes equal to or less than the target positional deviation amount, curing exposure for curing the resin 14 is performed. Although it depends on the type of device to be manufactured, for example, curing exposure is performed when the thickness is 10 nm or less.

  As described above, according to the present embodiment, it is possible to reduce vibration that affects the alignment accuracy between the mold 8 and the wafer 10 by performing preliminary exposure during the imprint process. Therefore, it is possible to suppress the occurrence of misalignment between the mold 8 and the wafer 10 during the curing process, and to improve the overlay accuracy of the pattern 20 existing in advance on the wafer 10 and the newly formed resin 14 pattern. it can.

(Third embodiment)
Next, an imprint apparatus 1 according to the third embodiment will be described. Depending on the type of resin 14 on the wafer, the start of curing is delayed even when an exposure amount necessary for curing is irradiated. In such a case, light irradiation for curing exposure may be started before entering the curing step (S5), that is, in the alignment step (S4). By starting the irradiation of light for curing exposure before entering the curing process, the light for curing exposure is used as the light for pre-exposure. Specifically, the time until the viscoelasticity of the uncured resin 14 becomes high and the shearing force of the resin 14 reaches a required magnitude after the irradiation of the curing exposure light is measured in advance. As the required magnitude of the shearing force, as shown in the first embodiment, the minimum value of the shearing force when aligning the pattern 20 and the pattern portion 8a is 0.1 N or more, preferably 0.3 N or more. Preferably it is 0.5N or more. Further, the maximum value of the shearing force is set to 10 N or less, preferably 5 N or less, more preferably 1 N or less. The light for curing exposure is irradiated before entering the curing process for the time until the shear force is reached. By doing so, the curing exposure light can be used as the preliminary exposure light. In the imprint apparatus according to the third embodiment, an optical filter may or may not be used to irradiate light from the light irradiation unit 2.

  Further, if the relationship between the positional deviation amount of the pattern 20 and the pattern portion 8a and the time required for the alignment can be grasped, even before the alignment step is completed, when the positional deviation amount is equal to or smaller than the predetermined positional deviation amount, Curing exposure may be started. Specifically, as the timing of starting curing exposure, irradiation of curing exposure light is started when the amount of positional deviation between the pattern 20 and the pattern portion 8a is 100 nm or less, preferably 50 nm or less, more preferably 25 nm or less. It is preferable to do. Further, the exposure amount of the curing exposure may be adjusted to be low in advance.

(Fourth embodiment)
Next, an imprint apparatus 1 according to the fourth embodiment will be described. The imprint apparatus 1 according to the fourth embodiment performs preliminary exposure in a stamping process in which the wafer 10 and the mold 8 are brought into contact with each other. The mold 8 is formed with a cavity (concave part) having a circular planar shape and a certain depth on the surface irradiated with the ultraviolet rays 9 so that the shape of the mold 8 can be easily changed.

  The mold 8 is configured in advance so as to enhance the airtightness of the cavity. By controlling the pressure of the cavity in the stamping process, the pattern portion of the mold 8 is deformed into a convex shape with respect to the substrate. Then, by bringing the mold 8 deformed into a convex shape into contact with the resin 14, the mold 8 and the resin 14 can be brought into contact in order from the center of the pattern portion toward the outer peripheral portion.

  The imprint apparatus 1 according to the fourth embodiment performs pre-exposure from the center to the outer periphery in accordance with the contact between the mold 8 and the resin 14. The digital mirror device shown in FIG. 4 is used as an example of a light adjuster that adjusts the light used for the pre-exposure.

  A digital mirror device (digital micromirror device) is referred to herein as “DMD”. The DMD 65 includes a plurality of mirror elements 80 arranged on the light reflecting surface, and individually adjusts each mirror element 80 in the plane direction to change the irradiation amount and irradiation position of the pre-exposure light. It is an adjustment means to adjust.

  FIG. 4 is a schematic diagram showing a surface configuration of DMD 65 that can be employed as an optical adjuster. As shown in FIG. 4A, the DMD 65 has a plurality of mirror elements 80 arranged in a lattice pattern. The DMD 65 is provided in the pre-exposure means 6, and the pre-exposure light is reflected by the mirror element 80 and irradiated with resin. Each of these mirror elements 80 can be changed in the surface direction based on an operation command from the control unit 7. That is, the DMD 65 can change the light reflection direction, and forms an arbitrary dose distribution to be irradiated toward the pattern 20.

  In the fourth embodiment, the reflection of the mirror element 80 of the DMD 65 is performed as shown in FIGS. 4B to 4F in accordance with the region where the mold 8 and the resin 14 are in contact with the plurality of mirror elements 80. Change direction. By performing such pre-exposure, the viscoelasticity of the resin 14 can be increased for each place where the mold 8 and the resin 14 are in contact with each other.

(Fifth embodiment)
Next, an imprint apparatus 1 according to the fifth embodiment will be described. When there is a difference between the shape of the pattern 20 formed on the wafer 10 and the shape of the pattern portion 8a of the mold 8, a technique for correcting the shape by applying heat to the wafer 10 or the mold 8 is known. In order to correct the shape of the pattern portion 8a or the pattern 20, the imprint apparatus 1 irradiates light having a wavelength with no sensitivity to the resin 14 (the resin 14 is not cured) as the heating light. In the fifth embodiment, the DMD 65 described in the fourth embodiment is used and the wafer 10 is also irradiated with heating light. In this case, the same DMD may be used to irradiate the pre-exposure and the heating light in terms of time. Alternatively, the DMD may be provided individually to irradiate the pre-exposure light and the heating light simultaneously. . If the sensitivity of the resin 14 is low, pre-exposure is performed first, followed by irradiation with heating light. If the pattern shape difference or pattern size difference is large, preliminary exposure may be performed after irradiation with heating light in advance.

  In the above-described embodiment, among the light irradiated from the light irradiation unit 2, light having a wavelength (first wavelength) that is highly sensitive to the resin 14 is used for curing exposure, and the resin 14 is exposed to light. In contrast, it was shown that light having a wavelength (second wavelength) having low sensitivity is used for the pre-exposure. In the fifth embodiment, in addition to two types of light, light having a wavelength that is not sensitive to the resin 14 (third wavelength) is used. The order of the wavelengths with high sensitivity to the resin 14 is the order of the first wavelength, the second wavelength, and the third wavelength.

  For example, if the main wavelength (first wavelength) of the ultraviolet ray 9 that cures the resin 14 is in the wavelength band of 200 to 400 nm, the resin 14 has higher viscoelasticity, but has a low sensitivity (second wavelength). Wavelength) exists in a wavelength band of 300 to 350 nm. Furthermore, the wavelength (third wavelength) that is not sensitive to the resin 14 exists in the wavelength band of 400 to 800 nm. The imprint apparatus 1 uses an optical filter that separates this light, separates it into light for curing exposure, light for preliminary exposure, and heating light for shape correction, and irradiates the wafer 10 via the DMD 65.

  At this time, a shape correction mechanism (not shown) that corrects the shape of the pattern portion 8a may be provided on the outer peripheral portion of the mold 8, and the shape of the pattern portion 8a may be corrected in the alignment step. Further, the distribution of the heating light may be adjusted in consideration of the deformation of the pattern shape of the wafer 10 and the mold 8 due to the preliminary exposure.

(Sixth embodiment)
Next, an imprint apparatus 1 according to the sixth embodiment will be described. As the thickness of the resin 14 applied between the wafer 10 and the mold 8 decreases, the force (shearing force) required for relative movement between the wafer 10 and the mold 8 increases. Using this property, the shear force is adjusted. In the imprint apparatus 1 of the present embodiment, as viscoelasticity adjusting means, a force necessary for relative movement of the wafer 10 and the mold 8 with respect to the thickness of the resin 14 to be applied is measured in advance, Thus, an application amount adjusting mechanism for adjusting the application amount of the resin 14 is provided.

  Specifically, the amount of the resin 14 discharged from the discharge nozzle 5a of the application unit 5 is adjusted in advance, and the wafer 10 and the mold 8 are set with the thickness of the resin 14 applied between the mold 8 and the wafer 10 as a parameter. Measure the force required for relative movement. The magnitude of the force can be determined by measuring the driving force of at least one of the mold driving mechanism 12 and the stage driving mechanism 17 when the wafer 10 and the mold 8 are relatively moved. This measurement may be performed on the imprint apparatus, or may be performed by other apparatuses.

  Based on the measurement result, the coating amount of the resin 14 is adjusted so as to obtain a predetermined force. Regarding the coating amount, the thickness of the resin 14 may be adjusted uniformly in the pattern portion to be formed, or the thickness of the pattern portion to be formed is partially narrowed to the extent that the pattern shape does not collapse during alignment. You may adjust so that the location to perform may be provided.

  Specifically, the resin 14 is applied to the application region inside the outer peripheral shape of the pattern portion 8a, and the pattern portion 8a and the resin 14 are brought into contact with each other. Approach 10 By doing so, you may adjust so that the location which makes the thickness of resin 14 partially narrow may be provided. Although the coating area on the substrate varies depending on the coating amount, the thickness of the resin 14 on the outer periphery of the pattern portion 8a is adjusted to be ½ or less compared to the thickness of the resin 14 inside the pattern portion 8a. It is desirable to do. By doing so, the minimum value of the force (shearing force) applied between the entire pattern portion 8a and the substrate is 0.1N or more, preferably 0.3N or more, more preferably 0.5N or more. be able to. Further, the maximum value of the shearing force is set to 10 N or less, preferably 5 N or less, more preferably 1 N or less.

  In addition, even when the detection position of the substrate by the alignment detection system 26 is inside the outer peripheral shape of the pattern portion 8a, the amount of the resin 14 applied at the detection position is reduced, and the resin 14 at the detection position of the alignment detection system 26 is reduced. It is desirable to reduce the thickness. In particular, when a pattern is formed in a region including the outer peripheral portion of the wafer 10, it is desirable to reduce the thickness of the resin 14 at the alignment detection location inside the outer peripheral shape of the pattern portion 8a and in the vicinity of the wafer outer peripheral portion. .

  The location where the thickness of the resin 14 is partially reduced is not limited to the inside of the pattern portion 8a. Even when the detection position of the substrate by the alignment detection system 26 is outside the outer peripheral shape of the pattern portion 8a, it is desirable to reduce the coating amount of the resin 14 so as to reduce the thickness of the resin 14 at the detection position.

  Moreover, about the location which narrows the thickness of the resin 14 of the pattern part 8a, when providing a several device inside the outer peripheral shape of the pattern part 8a etc., not only the detection location of the alignment detection system 26 but on a scribe line. It is desirable to reduce the thickness of the resin 14. By doing so, it is possible to suppress a change in the shape of the circuit pattern portion of the device due to a partial increase in the force applied between the mold 8 and the wafer 10.

  In this embodiment, the shear force is adjusted by changing the thickness of the resin 14 as a method for adjusting the shear force. As a method for adjusting the shearing force, the resin 14 may be mixed with a material that enhances viscoelasticity so that a force having a predetermined magnitude is obtained.

  In some cases, a condensable gas is supplied to the imprint space to perform an imprint operation. A method is known in which a condensable gas is confined between the mold 8 and the resin 14 applied on the wafer 10 and liquefied, thereby shortening the time required for the resin 14 to fill the pattern portion 8a. This condensable gas is known to reduce the viscoelasticity of the resin 14. Depending on the concentration of the condensable gas, the viscoelasticity of the resin 14 changes, and the shearing force generated during the alignment process is also reduced. Therefore, the concentration of the condensable gas is measured in advance, and the force required for the relative movement between the wafer 10 and the mold 8 generated during the alignment process is measured according to the concentration. This measurement may be performed on the imprint apparatus, or may be performed by other apparatuses. The imprint apparatus of this embodiment has supply gas adjusting means for adjusting the concentration of condensable gas supplied to the imprint apparatus as viscoelasticity adjusting means. The supply gas adjusting means supplies the condensable gas whose concentration is adjusted so as to have a predetermined force based on the measurement result.

  Further, the adjustment of the shearing force of the present embodiment can be carried out together with the adjustment of the shearing force by the preliminary exposure described in the above-described embodiment.

(Seventh embodiment)
Next, an imprint apparatus 1 according to the seventh embodiment will be described. It is known that when the resin 14 is cured by irradiation with exposure light, the time required for the resin 14 to cure is delayed due to impurities such as dissolved oxygen in the resin 14 and a polymerization inhibitor. In order to speed up the time required for curing the resin 14, the inert gas is purged on the imprint apparatus 1 to reduce the dissolved oxygen in the resin 14 and to purify and remove impurities such as polymerization inhibitors. Measures are taken.

  Therefore, in the imprint apparatus 1 of this embodiment, oxygen is intentionally supplied to the imprint apparatus 1 in order to adjust the curing time of the resin 14. The imprint apparatus 1 has oxygen supply means (supply gas adjustment means) for supplying oxygen between the mold 8 and the resin 14 as a viscoelasticity adjustment means in order to lengthen the curing time of the resin 14 by exposure. The oxygen supply means is disposed around the mold holding mechanism 3 and has a nozzle capable of supplying gas to the space between the mold 8 and the wafer 10. A gas may be supplied to the mold 8 from one direction, or a gas may be supplied so as to surround the mold 8.

  Further, a method is known in which He is supplied to the imprint apparatus 1 (He purge) to quickly fill the pattern portion 8a with the resin 14. Therefore, a mechanism for mixing a gas containing at least oxygen may be provided in the He supply means (supply gas adjusting means) for supplying He. It is necessary to suppress the oxygen concentration to such an extent that the filling property of the resin is not affected. Further, oxygen may be mixed and supplied to the condensable gas shown in the above embodiment. Also in this case, it is necessary to suppress the oxygen concentration to a level that does not affect the filling property of the resin. Further, oxygen may be mixed in a mixed gas obtained by mixing He and a condensable gas and supplied to the imprint apparatus 1.

  In the present embodiment, the method of supplying oxygen to the imprint apparatus 1 is shown in order to delay the curing. However, by intentionally mixing the polymerization inhibitor with the resin 14, the curing time can be lengthened and adjusted. good. By extending the curing time, it is possible to extend the time during which the viscoelasticity after the curing starts is low, and it is possible to provide the imprint apparatus 1 that is advantageous for aligning the mold 8 and the wafer 10.

  Further, the adjustment of the shearing force of the present embodiment can be performed together with the adjustment of the shearing force by the preliminary exposure described in the above-described embodiment.

(Product manufacturing method)
Any of the above-described imprint apparatuses is used for manufacturing a device such as a semiconductor device as an article. A pattern can be formed on a wafer, a glass plate, or an on-film substrate as a substrate.

  A method for manufacturing a device (semiconductor integrated circuit element, liquid crystal display element, etc.) as an article includes a step of forming a pattern on a substrate (wafer, glass plate, film-like substrate) using the above-described imprint apparatus. Furthermore, the manufacturing method may include a step of etching the substrate on which the pattern is formed. In the case of manufacturing other articles such as patterned media (recording media) and optical elements, the manufacturing method may include other processes for processing a substrate on which a pattern is formed instead of etching. The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Imprint apparatus 3 Mold holding mechanism 6 Pre-exposure means 7 Control part 9 Ultraviolet ray 16 Wafer chuck 21 Optical filter

Claims (20)

An imprint apparatus for forming a pattern on the substrate by aligning the mold and the substrate and curing the imprint material in a state where the mold is in contact with the imprint material on the substrate. ,
A light irradiation unit for irradiating light for curing the imprint material;
Means for irradiating the imprint material with light that is different in wavelength band or intensity from the light of the light irradiator and that enhances the viscoelasticity of the imprint material, An imprint apparatus that performs alignment with the substrate on which the imprint material is irradiated with light that enhances viscoelasticity.   2. The imprint according to claim 1, wherein the irradiating unit irradiates the imprint material with light that increases viscoelasticity of the imprint material after the mold and the imprint material are in contact with each other. apparatus.   Before curing the imprint material by irradiating light from the light irradiator, after increasing the viscoelasticity of the imprint material by the irradiating means, in a state where the light irradiation is stopped from the irradiating means. The imprint apparatus according to claim 1, further comprising a control unit configured to align the mold and the substrate.   It has a control unit that aligns the mold and the substrate before the imprint material is cured by light irradiation from the light irradiation unit and when the light irradiation is performed from the irradiation unit. The imprint apparatus according to claim 1 or 2.   5. The imprint apparatus according to claim 1, wherein the irradiating unit includes an optical filter that attenuates light emitted from the light irradiating unit.   The irradiating means includes an optical filter that transmits a part of the wavelength of the light emitted from the light irradiating unit, and light that enhances the viscoelasticity of the imprint material by the light transmitted through the optical filter. The imprint apparatus according to claim 1, wherein the imprint material is irradiated to the imprint material.   The irradiating means has an optical filter that reflects a part of the wavelength of the light emitted from the light irradiating unit, and light that enhances the viscoelasticity of the imprint material by the light reflected from the optical filter. The imprint apparatus according to claim 1, wherein the imprint material is irradiated to the imprint material.   The means for irradiating includes a light source that emits light of a second wavelength that is lower in sensitivity to the imprint material than light of the first wavelength that is irradiated from the light irradiation unit and cures the imprint material. The imprint apparatus according to any one of claims 1 to 4.   The viscoelasticity of the imprint material is obtained by irradiating light from the irradiating means so that the shear force of the imprint material generated by relative movement of the substrate and the mold is 0.1 N or more and 10 N or less. The imprint apparatus according to claim 1, wherein the imprint apparatus is heightened.   The exposure amount irradiated to the imprint material from the irradiation means is 1/10 or less of the exposure amount necessary to cure the imprint material. The imprint apparatus according to claim 1. Having vibration detecting means for detecting vibration of the substrate or the mold;
The imprint apparatus according to any one of claims 1 to 10, wherein the irradiating unit irradiates the imprint material with light until a detection result of the vibration detecting unit becomes a predetermined value or less. .   12. The vibration detection means is at least one of an alignment detection means for detecting a positional deviation between the substrate and the mold and a position measurement means for a substrate stage that holds the substrate. Imprint device.   The imprint apparatus according to claim 1, wherein the irradiating unit includes an adjusting unit that adjusts an irradiation position of light irradiated to the imprint material. An imprint apparatus for forming a pattern on the substrate by aligning the mold and the substrate and curing the imprint material in a state where the mold is in contact with the imprint material on the substrate. ,
A light irradiation unit for irradiating the imprint material with light;
A control unit for controlling the imprint apparatus,
The control unit
By increasing the viscoelasticity of the imprint material by irradiating the imprint material with the light irradiation section, the magnitude of the shear force of the imprint material generated by the relative movement of the substrate and the mold is 0.1N. More than 10N,
Positioning the substrate and the mold on which light that enhances the viscoelasticity of the imprint material is irradiated on the imprint material by the light irradiation unit,
The imprint apparatus, wherein the imprint material is cured by irradiating the imprint material with the light irradiation unit. An imprint apparatus for forming a pattern on the substrate by aligning the mold and the substrate and curing the imprint material in a state where the mold is in contact with the imprint material on the substrate. ,
A light irradiation unit for irradiating light for curing the imprint material;
Viscoelasticity adjusting means for increasing the viscoelasticity of the imprint material,
The viscoelasticity adjusting means is an application amount adjusting means for adjusting an application amount of the imprint material applied on the substrate so that the viscoelasticity of the imprint material becomes a predetermined viscoelasticity, and the application amount adjustment An imprint apparatus characterized in that alignment is performed with respect to a substrate in which the viscoelasticity of the imprint material becomes a predetermined viscoelasticity. An imprint apparatus for forming a pattern on the substrate by aligning the mold and the substrate and curing the imprint material in a state where the mold is in contact with the imprint material on the substrate. ,
A light irradiation unit for irradiating light for curing the imprint material;
Viscoelasticity adjusting means for increasing the viscoelasticity of the imprint material,
The viscoelasticity adjusting means is a supply gas adjusting means for supplying a gas between the substrate and the mold so that the viscoelasticity of the imprint material applied on the substrate becomes a predetermined viscoelasticity, An imprinting apparatus characterized in that alignment is performed with respect to a substrate having a predetermined viscoelasticity of the imprint material by a supply gas adjusting means. An imprint that forms a pattern on the substrate by curing the imprint material by irradiating the imprint material with light that cures the imprint material in a state where the mold is in contact with the imprint material on the substrate. Printing method,
Irradiating the imprint material with light that is different in wavelength or intensity from the light that cures the imprint material, and that enhances the viscoelasticity of the imprint material;
Aligning the mold with the substrate irradiated with light that enhances the viscoelasticity of the imprint material; and
A light irradiation step of irradiating light for curing the imprint material;
An imprint method characterized by comprising a front. An imprint method for forming a pattern on the substrate by curing the imprint material in a state where a mold is in contact with the imprint material on the substrate,
Irradiating the imprint material with light that enhances the viscoelasticity of the imprint material so that the shear force of the imprint material generated by relative movement of the substrate and the mold is 0.1 N or more and 10 N or less. And a process of
Aligning the mold with the substrate irradiated with light that enhances the viscoelasticity of the imprint material; and
A light irradiation step of irradiating light for curing the imprint material. An imprint method for forming a pattern on the substrate by curing the imprint material in a state where a mold is in contact with the imprint material on the substrate,
A viscoelasticity adjusting step for increasing the viscoelasticity of the imprint material,
Aligning the mold and the substrate;
A light irradiation step of irradiating light for curing the imprint material,
In the viscoelasticity adjusting step, the application amount adjusting step of adjusting the application amount of the imprint material applied on the substrate so that the viscoelasticity of the imprint material becomes a predetermined viscoelasticity, or on the substrate The imprint includes at least one of a supply gas adjustment step of adjusting a gas supplied between the substrate and the mold so that a viscoelasticity of the applied imprint material becomes a predetermined viscoelasticity. Method. Forming an imprint material pattern on the substrate using the imprint apparatus according to any one of claims 1 to 16, and
A step of processing the substrate on which the pattern is formed in the step;
A method for producing an article comprising:

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