JP4963718B2 - Imprint method, imprint apparatus, and article manufacturing method using the same - Google Patents

Description

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

  Imprint (nanoimprint) technology enables transfer of nanoscale fine patterns and has been put to practical use as one of nanolithography technologies for mass production of magnetic storage media and semiconductor devices. In the imprint process, a fine pattern is formed on a substrate such as a silicon wafer or a glass plate using a mold (mold material) on which a fine pattern is formed using an apparatus such as an electron beam drawing apparatus as an original plate. The fine pattern is formed by applying an imprint resin (hereinafter simply referred to as “resin”) on a substrate, pressing a mold pattern against the resin, and then curing the resin.

  As the imprint technique, there are generally a thermal cycle method and a photocuring method. In the thermal cycle method, a thermoplastic resin is heated to a temperature equal to or higher than the glass transition temperature, the mold is pressed in a state where the flowability of the resin is increased, and after cooling, the mold is pulled away from the resin. On the other hand, in the photocuring method, an ultraviolet curable resin is used, and the resin is cured by irradiating ultraviolet rays in a state where the mold is pressed, and then the mold is separated from the cured resin. The thermal cycle method is accompanied by an increase in transfer time due to temperature control and a decrease in dimensional accuracy due to temperature change. However, the photocuring method does not have such a problem. Therefore, in mass production of nanoscale semiconductor devices, A curing method is advantageous. As a manufacturing apparatus for mass production of semiconductor devices employing this photocuring method, an apparatus applying step-and-flash imprint lithography (hereinafter referred to as “SFIL”) is effective. For example, Patent Document 1 discloses a nanoimprint apparatus that includes a substrate stage, a resin coating mechanism, an imprint head, a light irradiation system, and a positioning mark detection mechanism and is compatible with SFIL.

Japanese Patent No. 4185941

  However, in the conventional imprint apparatus, there are cases where the application amount and application position by the resin application mechanism vary, and the resin cannot be accurately applied to a predetermined shot. For example, if the resin that protrudes from the mold in a certain shot is cured as it is, it diffuses and cures on the surrounding shots, resulting in many defective shots. Further, when the coating amount is small or when the coating is concentrated on a part of the region, the resin does not spread over the entire shot and the shot becomes defective.

  The present invention has been made in view of such circumstances, and provides an imprint method and an imprint apparatus that can reduce defective shots by adjusting the application state of a resin applied on a substrate. The purpose is to do.

  In order to solve the above problems, the present invention is an imprint method in which a pattern formed on a mold is imprinted on a resin applied to a substrate, and the pattern is transferred to the resin. The resin receives ultraviolet rays. A step of imprinting the mold onto the resin applied to the substrate, an inspection step of inspecting the application state of the resin to the region to be processed on the substrate, and the inspection step Then, based on the inspection result of the inspection process, an adjustment process for adjusting the application range of the resin, a curing process for irradiating the resin with ultraviolet rays after the adjustment process, and a mold release from the resin after the curing process And a mold release step.

  According to the present invention, since the application range of the resin is adjusted before the curing step depending on the application state of the ultraviolet curable resin applied on the substrate, the application range can be set to an accurate position with respect to the processing area. As a result, defective shots can be reduced.

It is the schematic which shows the structure of the imprint apparatus which concerns on embodiment of this invention. It is the schematic which shows the application | coating state of resin in the to-be-processed surface of a wafer. It is a flowchart which shows the process by the imprint method of 1st Embodiment. It is the schematic which shows the fine operation | movement of a mold. It is a flowchart which shows the process by the imprint method of 2nd Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
First, the configuration of the imprint apparatus according to the embodiment of the present invention will be described. FIG. 1 is a schematic diagram illustrating a configuration of an imprint apparatus. The imprint apparatus according to the present embodiment is a processing apparatus that transfers a concavo-convex pattern of a mold onto a wafer (on a substrate) that is a substrate to be used, which is used in a semiconductor device manufacturing process, and an imprint (nanoimprint) technique. Among them, it is an apparatus that employs a photocuring method. In the following figure, the Z axis is taken in parallel to the ultraviolet irradiation axis for the mold, and the X axis is taken in a direction perpendicular to the Z axis in the direction in which the wafer stage moves with respect to the coating mechanism described later. A description will be given by taking the Y axis in a direction perpendicular to the X axis. The imprint apparatus 1 includes an illumination system unit 2, a half mirror 3, a mold 4, a head mount 5, a wafer 6, a wafer stage 7, a coating device 8, a monitor 9, and a control device 10.

  The illumination system unit 2 is illumination means for irradiating the mold 4 with ultraviolet rays during the imprint process. The illumination system unit 2 includes a light source and a plurality of optical elements for adjusting ultraviolet rays emitted from the light source to light suitable for imprinting. Here, as will be described later, the imprint apparatus 1 installs a monitor 9 above the ultraviolet irradiation surface of the mold 4. Therefore, the illumination system unit 2 is arranged on the upper side of the ultraviolet irradiation surface of the mold 4 and is a half installed between the head mount 5 and the monitor 9 for the ultraviolet rays irradiated in the horizontal direction (X-axis direction). The mold 3 is refracted by 90 degrees and irradiated to the mold 4. The half mirror 3 reflects ultraviolet rays but has a property of transmitting visible light.

  The mold 4 is a mold material in which a predetermined concavo-convex pattern (for example, a circuit pattern) is formed in a three-dimensional shape on the surface facing the wafer 6. The surface of the concavo-convex pattern is processed with high flatness in order to maintain adhesion with the surface of the wafer 6. The material of the mold 4 is a material that can transmit ultraviolet rays, such as quartz.

  Although not shown, the head mount 5 is a mold holding unit including a head that holds and fixes the mold 4, a drive mechanism that drives the head, and a plurality of scopes 11. Specifically, the drive mechanism is a drive system that drives the head in the Z-axis direction in order to press the mold 4 against the ultraviolet curable resin formed on the wafer 6. The actuator employed in the drive mechanism is not particularly limited as long as it is driven at least in the Z-axis direction, and a linear motor, an air cylinder, or the like can be employed. Alternatively, in order to perform the mold release operation with high accuracy so that the cured UV curable resin is not destroyed during the mold release operation in which the mold 4 is separated from the UV curable resin, the coarse operation and the fine operation are performed separately. An actuator may be used. The scope 11 is a position measuring unit that optically observes the alignment mark formed on the mold 4 and the alignment mark formed on the wafer 6 and measures the relative positional relationship between them. Since the scope 11 only needs to be able to measure the relative positional relationship between the mold 4 and the wafer 6, an imaging optical system for observing both of them may be configured inside, or the interference signal and moire ( A signal due to a synergistic effect such as (interference fringes) may be detected.

  The wafer 6 is a substrate to be processed made of, for example, single crystal silicon, and an ultraviolet curable resin 12 to be a molding portion is applied to the surface to be processed. The wafer stage 7 is a substrate stage that holds the wafer 6 by vacuum suction and can freely move in the XY plane. As an actuator for driving the wafer stage 7, a linear motor can be adopted, but it is not particularly limited.

  The coating device 8 is a coating unit that coats the ultraviolet curable resin 12 on the wafer 6. The ultraviolet curable resin is a resin (imprint resin) having a property of being cured by receiving ultraviolet rays, and is appropriately selected depending on the type of semiconductor device to be manufactured. Hereinafter, for the sake of simplicity, the ultraviolet curable resin is simply referred to as “resin”.

  The monitor 9 is an imaging unit installed above the irradiation axis (Z axis) of the ultraviolet rays that irradiate the mold 4. The monitor 9 first irradiates the surface of the wafer 6 with visible light from the internal illumination system, and illuminates the molding part with visible light transmitted through the half mirror 3. Thereafter, the monitor 9 receives the reflected light and images the state of the molding part. Note that a CCD camera, a CMOS camera, or the like is preferable as the image pickup element employed in the monitor 9.

  The control device 10 is a control unit that controls the operation, adjustment, and the like of each component of the imprint apparatus 1. Although not shown, the control device 10 is composed of a computer having a storage device such as a magnetic storage medium connected to each component of the imprint device 1 by a line, a sequencer, etc., and the imprint method of the present invention. Are executed as a program or a sequence. Note that the control device 10 may be configured integrally with the imprint device 1 or may be installed at a location different from the imprint device 1 and controlled remotely.

  Next, the operation of the imprint method according to this embodiment will be described. First, the imprint apparatus 1 places and fixes the wafer 6 on the wafer stage 7, and then moves the wafer stage 7 to the coating position of the coating apparatus 8. Next, the coating apparatus 8 applies the resin 12 to a predetermined shot (processed area) of the wafer 6. Next, the imprint apparatus 1 moves the wafer stage 7 directly below the mold 4, aligns the stamping surface of the mold 4 with the coating surface on the wafer 6, and then moves the drive mechanism in the head mount 5. The mold 4 is impressed on the resin 12 on the wafer 6 by driving. At this time, the resin 12 flows along the concavo-convex pattern formed on the mold 4 by the stamping of the mold 4. In this state, the illumination system unit 2 irradiates ultraviolet rays from the back surface (upper surface) of the mold 4, and the resin 12 is cured by the ultraviolet rays transmitted through the mold 4. After the resin 12 is cured, the imprint apparatus 1 re-drives the drive mechanism in the head mount 5 to release the mold 4 from the wafer 6. As a result, a layer of the resin 12 having a three-dimensional shape following the uneven pattern of the mold 4 is formed on the surface of the shot on the wafer 6.

  FIG. 2 is a schematic view showing the processing surface on the wafer 6 and the order in which the imprint processing is performed for each shot on the wafer 6 and the state thereof. In FIG. 2, the blackened area is a shot with a concavo-convex pattern, and the white area is an unshaped shot. As shown by the arrows in FIG. 2, the imprint apparatus 1 generally has a high volatility of the resin 12, so that the resin 12 is applied only to a shot that is once molded, and the mold 4 is imprinted to form an uneven pattern. Repeat for each shot. At this time, if the coating device 8 cannot accurately apply the resin 12 to a predetermined shot, the resin 12 protrudes to the surrounding shots and is simultaneously cured during the curing process in the predetermined shot. There is a possibility that a problem occurs when forming an uneven pattern. The area surrounded by the dotted line in FIG. 2 shows a state where the resin 12 is applied wider than the shot area to be applied and the resin 12 protrudes from the peripheral shots. Therefore, in this embodiment, the following imprint method is adopted.

  FIG. 3 is a flowchart showing the flow of processing of the imprint apparatus 1 in the present embodiment. First, the control device 10 instructs the coating device 8 to apply the resin 12 to a predetermined shot on the wafer 6 (step S100). Next, the control device 10 moves the wafer stage 7 so that the application region of the resin 12 applied on the wafer 6 coincides with the stamping position of the mold 4 (step S101). Next, the control device 10 drives the drive mechanism in the head mount 5 to impress the mold 4 against the resin 12 applied on the wafer 6 (imprinting step: step S102). Further, the control device 10 uses the monitor 9 in this state to inspect the application state of the resin 12 on the shot (inspection step: step S103). The imprint apparatus 1 according to the present embodiment inspects the application state of the resin 12 only with the monitor 9. For example, a grazing incidence type film thickness measuring apparatus such as an ellipsometer is separately installed and molded. It is good also as a structure which can measure a periphery. Further, the inspection of the application state of the resin 12 may be performed before the mold 4 is stamped as long as the resin 12 is applied.

  In step S <b> 103, when the control device 10 determines that the resin 12 protrudes from the predetermined shot or is not satisfied, the control device 10 drives the drive mechanism in the head mount 5 to set the interval between the mold 4 and the wafer 6. Fine adjustment is made (adjustment process: step S104). FIG. 4 is a schematic view showing the operation of the mold 4 in the present embodiment. In FIG. 4, the same components as those in FIG. First, as shown in FIG. 4A, when the resin 12 is applied out of the shot, that is, when the application width of the resin 12 is wider than the shot width L, as shown in FIG. As usual, the mold 4 is once stamped on the resin 12. Here, after sufficient time has passed for the mold 4 and the resin 12 to become sufficiently familiar, that is, a sufficient time for the resin 12 to reach every corner of the uneven pattern of the mold 4, the control device 10 drives the drive in the head mount 5. The mechanism is driven to widen the gap between the mold 4 and the wafer 6 by a necessary amount. By this operation, the resin 12 is pulled toward the mold 4 by the surface tension with the mold 4 and is drawn into a region along the mold 4 as shown in FIG. As a result, the resin 12 that has protruded from the surrounding shots is collected in a predetermined shot area, and the coating range is adjusted. Here, the adjustment amount of the interval between the mold 4 and the wafer 6 is determined by the control device 10 by analogizing the amount of protrusion of the resin 12 based on the inspection result inspected by the monitor 9. For example, when the amount of protrusion of the resin 12 is measured with an ellipsometer separately installed, the mold 4 is stopped at a place where the signal to the protruding resin 12 disappears while widening the interval between the mold 4 and the wafer 6. 4 and the adjustment amount of the space | interval of the wafer 6 can be determined. On the other hand, unlike FIG. 4, when the resin 12 is not filled in the required area of the shot, that is, not sufficiently filled, the control device 10 causes the head mount to reduce the distance between the mold 4 and the wafer 6. The drive mechanism in 5 is driven. As a result, the resin 12 can be sufficiently filled in the necessary region.

  On the other hand, when the control device 10 determines in step S103 that the resin 12 is normally applied, or after the adjustment to be in the normal state is completed in step S104, the control device 10 proceeds to the resin 12 curing process. (Curing process: Step S105). After completing the curing process, the control device 10 drives the drive mechanism in the head mount 5 to release the mold 4 from the resin 12 (release process: step S106), and proceeds to the imprint process process for the next shot. (Step S107).

  As described above, according to the imprint method of the present invention, when the resin 12 protrudes from a necessary area of a predetermined shot or is not sufficiently filled, it can be quickly recovered, so that a defective shot is generated. The rate can be lowered and productivity can be improved.

(Second Embodiment)
Next, an imprint method according to the second embodiment of the present invention will be described. FIG. 5 is a flowchart showing the flow of processing of the imprint apparatus 1 in the present embodiment. In FIG. 5, the same processes as those in the flowchart of FIG. The imprint method of this embodiment is characterized in that when the resin 12 protrudes from a predetermined shot, the mold 4 is released until the protruding resin 12 is vaporized without adjusting the interval between the mold 4 and the wafer 6. It is in the point which adjusts an application range by not performing. First, in step S103, when the control device 10 determines that the resin 12 is protruding from a predetermined shot, the control device 10 waits until the protruding resin 12 is vaporized (adjustment step: step S204). By making the mold 4 stand by in a stamped state, only the protruding portion of the resin 12 is in contact with the surrounding atmosphere, so that only the protruding resin 12 is vaporized and eliminated. Further, since the resin 12 has high volatility, in order to promote vaporization, for example, a gas may be blown around the mold 4 to shorten the vaporization time. Thus, as in the first embodiment, when the resin 12 protrudes from the required area of a predetermined shot, it can be quickly recovered, so the rate of defective shots can be reduced and productivity can be improved. . Since a normal imprint process takes a relatively long time for each shot, the vaporization standby time is included in the normal pattern formation time, and has little effect on productivity.

(Product manufacturing method)
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.

(Other embodiments)
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.

  In the first embodiment, the distance between the mold 4 and the wafer 6 is adjusted by driving the drive mechanism in the head mount 5 and changing the position of the mold 4. It is not limited. For example, in adjusting the distance between the mold 4 and the wafer 6, the wafer stage 7 may be driven, or both the mold 4 and the wafer stage 7 may be driven.

DESCRIPTION OF SYMBOLS 1 Imprint apparatus 4 Mold 6 Wafer 10 Control apparatus 12 UV curable resin

Claims (7)

An imprint method for imprinting a pattern formed on a mold on a resin applied to a substrate and transferring the pattern to the resin,
The resin is an ultraviolet curable resin that is cured by receiving ultraviolet light;
A stamping step of stamping the mold onto the resin applied to the substrate;
After the stamping step, an inspection step for inspecting the application state of the resin to the processing area on the substrate;
After the inspection step, based on the inspection result of the inspection step, an adjustment step of adjusting the application range of the resin,
After the adjustment step, a curing step of irradiating and curing the resin with ultraviolet rays,
After the curing step, a mold release step for releasing the mold from the resin;
The imprint method characterized by having.   The imprint method according to claim 1, wherein the adjusting step changes a distance between the mold and the substrate. In the inspection step, when it is determined that the resin is applied beyond the area to be processed,
The imprinting method according to claim 2, wherein the adjusting step increases a distance between the mold and the substrate. In the inspection step, when it is determined that the resin is not filled in the region to be processed,
The imprinting method according to claim 2, wherein the adjusting step narrows a distance between the mold and the substrate. In the inspection step, when it is determined that the resin is applied beyond the area to be processed,
The imprinting method according to claim 1, wherein the adjustment step waits until the protruding resin is vaporized.   An imprint apparatus comprising: a control unit that executes the imprint method according to claim 1 as a program or a sequence. Forming a pattern on a substrate using the imprint apparatus according to claim 6;
Processing the substrate on which the pattern is formed in the step;
A method for producing an article comprising:

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