JP6674218B2 - Imprint apparatus, imprint method, and article manufacturing method - Google Patents

Description

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

  The imprint technology is a technology that enables the transfer of a fine pattern on the nanoscale, and is attracting attention as one of the nanolithography technologies for mass production of semiconductor devices and magnetic storage media. An imprint apparatus using imprint technology cures a resin in a state where a mold on which a pattern is formed and a resin (imprint material) on a substrate are brought into contact with each other, and then separates the mold from the cured resin to remove the resin from the cured resin. To form a pattern.

  In an imprint apparatus, it is effective to determine the quality of a pattern formed on a substrate, that is, the quality of an imprint process, based on imaging information from an imaging unit arranged above the substrate (see Japanese Patent Application Laid-Open No. H11-163,837). reference). Patent Literature 1 discloses that an image obtained by imaging a pattern formed on a substrate by an imprint process is compared with a reference image prepared by imaging a pattern normally formed on the substrate in advance. A technique for determining the quality of imprint processing is disclosed.

JP 2011-3616 A

  The determination of the quality of the imprint process is performed not after the pattern is formed on the substrate but during the imprint process, for example, when an abnormality occurs, it is possible to suppress the influence of the abnormality, It leads to improvement of productivity. However, the state of the substrate during the imprinting process is such that the resin is supplied (coated), the mold is brought into contact with the resin, and the pattern is formed by separating the mold according to the process of the imprinting process. Change to a state such as Therefore, if the criterion for determining the quality of the imprint processing is constant, the criterion is inappropriate depending on the state of the substrate, and the state of the substrate cannot be correctly grasped, that is, the quality of the imprint processing cannot be determined correctly. . Also, while the resin on the substrate is being filled in the pattern of the mold, the state of the substrate changes sequentially due to a physical phenomenon (capillary phenomenon), so it is difficult to specify the timing for determining the quality of the imprint process. .

  The present invention has been made in view of such problems of the related art, and has an exemplary object to provide an imprint apparatus that is advantageous for determining whether or not imprint processing is good.

In order to achieve the above object, an imprint apparatus according to one aspect of the present invention is an imprint apparatus that forms a pattern using a mold on an imprint material on a substrate, and at least one of the mold and the substrate. An imaging unit that acquires an image of the image, and a determination unit that determines whether the imprint processing is good or bad. The imprint processing includes a first step of supplying an imprint material on the substrate, the mold, and the mold. And a second step of contacting the imprint material on the substrate, the determination unit, after positioning the substrate supplied with the imprint material with respect to the mold, the imaging unit through the mold through the mold The quality of the imprint process in the first step with respect to a first criterion is determined based on the image acquired in the first step. To determine the quality for different second criterion and said first reference print processing, at least, is contacted in a state where the mold to the imprint material is deformed into a convex shape on the substrate side between the imprint process In a state where the mold is deformed into the convex shape, and in a state where the mold is returned to the original state and is in contact with the imprint material while determining whether the mold is good or bad while switching between the first reference and the second reference. Is performed.

  Further objects and other aspects of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, for example, it is possible to provide an imprint apparatus that is advantageous for determining whether imprint processing is good or bad.

FIG. 1 is a schematic diagram illustrating a configuration of an imprint apparatus as one aspect of the present invention. FIG. 2 is a diagram illustrating an example of interference fringes observed by an observation unit of the imprint apparatus illustrated in FIG. 1. 9 is a flowchart illustrating a general imprint process. FIG. 9 is a diagram for explaining a general imprint process. 5 is a flowchart illustrating an imprint process according to the embodiment. FIG. 6 is a diagram for describing a determination as to whether the imprint processing shown in FIG. 5 is good or not (S202). FIG. 6 is a diagram for describing determination of whether or not imprint processing shown in FIG. 5 is good (S203). FIG. 6 is a diagram for explaining the timing of determining whether or not the imprint processing shown in FIG. 5 is good (S203). FIG. 6 is a diagram for explaining the timing of determining whether or not the imprint processing shown in FIG. 5 is good (S204). FIG. 6 is a diagram for explaining the timing of determining whether or not the imprint processing shown in FIG. 5 is good (S204). FIG. 6 is a diagram for describing determination of whether or not the imprint processing shown in FIG. 5 is good (S206). FIG. 6 is a diagram for explaining the timing of determining whether or not the imprint processing shown in FIG. 5 is good (S206). FIG. 6 is a diagram for describing determination of whether or not imprint processing shown in FIG. 5 is good (S207). FIG. 6 is a diagram for describing determination of whether or not the imprint processing shown in FIG. 5 is good (S205). FIG. 6 is a diagram for describing determination of whether or not the imprint processing shown in FIG. 5 is good (S205). FIG. 6 is a diagram for describing determination of whether or not the imprint processing shown in FIG. 5 is good (S205).

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same members are denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a schematic diagram illustrating a configuration of an imprint apparatus 100 according to one aspect of the present invention. The imprint apparatus 100 is a lithography apparatus that forms a pattern on an imprint material on a substrate using a mold. In the present embodiment, a case is described in which an ultraviolet-curable resin that is cured by irradiating ultraviolet rays is used as the imprint material, but the imprint material may be a thermoplastic or thermosetting resin.

  The imprint apparatus 100 includes a substrate chuck 1 that holds a substrate W, a substrate stage 2 that moves while supporting the substrate chuck 1, a mold chuck 3 that holds a mold M on which a pattern P is formed, and a mold chuck 3. And a mold stage 4 that moves while being supported. Further, the imprint apparatus 100 includes a dispenser 11 that supplies the resin R onto the substrate, and a control unit 12 that controls the entire imprint apparatus 100. Further, the imprint apparatus 100 includes a console unit 13 for generating an operation screen, a display unit 14 for displaying the operation screen, an input device 15 such as a keyboard and a mouse, and a contact between the mold M and the resin R on the substrate. A force sensor 16 for detecting a generated force. When the substrate W supplied with the resin R is carried into the imprint apparatus 100 by an external apparatus different from the imprint apparatus 100, the imprint apparatus 100 may not have the dispenser 11.

  The imprint apparatus 100 forms a pattern on the substrate by curing the resin R in a state where the resin R on the substrate supplied from the dispenser 11 and the old 40 are in contact with each other, and separating the mold M from the cured resin R. Perform imprint processing. The imprint process includes a supply process, a stamping process, a curing process, and a release process. The supply process is a process of supplying the resin R onto the substrate (first step). The stamping process is a process (second step) of bringing the mold M into contact with the resin R on the substrate. By bringing the mold M into contact with the resin R on the substrate, that is, pressing the mold M against the resin R, the resin R fills the pattern P of the mold M. The curing process is a process of curing the resin R in a state where the mold M is in contact with the resin R on the substrate. The release process is a process (third step) of separating the mold M from the cured resin R on the substrate.

  In the mold chuck 3, a concave portion having an area larger than the area of the pattern P is formed on a surface of the mold M opposite to the pattern surface. The concave portion is closed by the mold M and a seal glass (not shown) to define a closed space (cavity). A pressure control unit (not shown) is connected to the cavity, and the pressure in the cavity can be controlled. When the mold M is brought into contact with the resin R on the substrate, the pressure in the cavity is increased to deform the mold M into a convex shape toward the substrate, so that bubbles are generated between the mold M and the resin R on the substrate. Suppress pinching. Then, when the mold M comes into contact with the resin R on the substrate, the pressure in the cavity is released so that the mold M becomes parallel to the substrate W (completely contacts the resin R on the substrate).

  The imprint apparatus 100 further includes an alignment scope 5 that detects an alignment mark (substrate-side mark) 6 provided on the substrate W and an alignment mark (mold-side mark) 7 provided on the mold M. The alignment scope 5 functions as an alignment detection unit that detects the substrate-side mark 6 formed in the shot area of the substrate W and the mold-side mark 7 formed in the pattern P of the mold M and generates an alignment signal. I do. As a method of detecting the substrate side mark 6 and the mold side mark 7, for example, a method of detecting moiré fringes (interference fringes) reflecting the relative positions of the two marks can be used. Further, the respective images of the substrate side mark 6 and the mold side mark 7 may be detected to determine the relative positions of the two marks.

  The control unit 12 includes a CPU, a memory, and the like, and controls each unit of the imprint apparatus 100 to perform an imprint process. For example, the control unit 12 obtains a relative position (displacement) between the mold M and the substrate W based on the detection result of the substrate side mark 6 and the mold side mark 7 by the alignment scope 5. Then, the control unit 12 moves the substrate stage 2 and the mold stage 4 based on the relative position between the mold M and the substrate W so that the positional deviation between the mold M and the substrate W is corrected. The displacement between the mold M and the substrate W includes a shift component, a magnification component, a rotation component, and the like. Further, the control unit 12 can correct the shape of the pattern P of the mold M according to the shape of the shot area of the substrate W using a pressure finger (not shown) arranged around the mold M. It is. Further, as described later, in the present embodiment, the control unit 12 functions as a determination unit that determines whether or not imprint processing is good.

  The imprint apparatus 100 further includes a light source 8 that emits ultraviolet light, an observation unit 9 that observes at least one of the mold M and the substrate W, and a mirror 10. The mirror 10 includes a dichroic mirror, and has a characteristic of reflecting ultraviolet light from the light source 8 and transmitting light (observation light) from the observation unit 9. The pattern P of the mold M is formed on the substrate by reflecting the ultraviolet light from the light source 8 on the mirror 10 and irradiating the resin R on the substrate through the mold M to cure the resin R.

  The observation unit 9 includes an observation light source 9a and an imaging element 9b, and functions as an imaging unit that captures an image by capturing at least one of the mold M and the substrate W. The observation light from the observation light source 9a passes through the mirror 10 and the mold M to illuminate the substrate W (shot area). The imaging element 9b detects light reflected on the surface of the substrate W and light reflected on the pattern surface of the mold M as observation light. As described above, when the mold M is brought into contact with the resin R on the substrate, the mold M is deformed into a convex shape toward the substrate side. The gap between the substrate and the substrate W changes continuously. Therefore, the imaging element 9b captures an image of interference fringes between light reflected on the surface of the substrate W and light reflected on the pattern surface of the mold M, that is, a so-called Newton ring. FIG. 2 is a diagram illustrating an example of interference fringes observed by the observation unit 9, where FIG. 2A illustrates a gap between the mold M and the substrate W, and FIG. The image captured by the element 9b is shown.

  A general imprint process will be described with reference to FIGS. 3 and 4A to 4F. As shown in FIG. 3, the imprint process includes a supply process (S101), a stamping process (S102), a curing process (S103), and a release process (S104). FIGS. 4A to 4F are diagrams showing changes in the state of the substrate W in the imprint process.

  FIG. 4A shows a state of the substrate W before the imprint processing is started. As shown in FIG. 4A, the substrate W is in an unprocessed state.

  FIG. 4B shows a state of the substrate W on which the supply processing has been performed. In the supply process, the resin R is supplied to the substrate W by discharging droplets of the resin R from the dispenser 11 onto the substrate. As shown in FIG. 4B, the droplets of the resin R are supplied to predetermined positions on the substrate, and the arrangement of the droplets of the resin R is formed on the substrate.

  FIG. 4C shows a state of the substrate W in the stamping process. In the stamping process, as shown in FIG. 4 (c), the mold M is brought closer to the substrate W in a state where the mold M is deformed in a convex shape toward the substrate side, so that the mold M is gradually moved from the center to the periphery of the mold M. Is brought into contact with the resin R on the substrate. Therefore, in the stamping process, a gap is generated between the mold M and the substrate W, and interference fringes as shown in FIG. 2B are observed.

  FIG. 4D shows a state of the substrate W in the curing process. In the curing step, the resin R is cured by irradiating the resin R with ultraviolet light from the light source 8 in a state where the mold M is in contact with the resin R on the substrate. As shown in FIG. 4D, in the curing step, the mold M is completely in contact with the resin R on the substrate, and the pattern P of the mold M is filled with the resin R.

  FIG. 4E shows a state of the substrate W in the release processing. In the release processing, as shown in FIG. 4E, the mold M is formed into a convex shape on the substrate side in order to reduce the release force, which is a force for separating the mold M from the cured resin R on the substrate. The mold M is separated from the substrate W while being deformed. Therefore, in the release process, a gap is generated between the mold M and the substrate W, as in the stamping process, and interference fringes as shown in FIG. 2B are observed.

  FIG. 4F shows the state of the substrate W at the end of the imprint process. As shown in FIG. 4F, a pattern of the resin R corresponding to the pattern P of the mold M is formed on the substrate W.

  As described above, the state of the substrate W during the imprint process changes according to each process of the imprint process. However, in the prior art, after the pattern of the resin R corresponding to the pattern P of the mold M is formed on the substrate W (the state of the substrate W shown in FIG. 4F), the quality of the imprint process is determined. In other words, the prior art is specialized in determining the quality of the imprint process after the release process, and in other processes in the imprint process, the quality of the imprint process can be correctly determined. Can not.

  Therefore, in the present embodiment, the quality of the imprint process is determined during the imprint process, that is, in each process of the imprint process. At this time, as will be described later, the criterion for determining whether the imprint processing is good or not is changed for each of the imprint processing. In other words, an imprint suitable for each of the supply process (S101), the stamping process (S102), the curing process (S103), and the release process (S104) shown in FIG. The process is switched to the determination of the quality of the process.

  FIG. 5 is a flowchart illustrating the imprint process according to the present embodiment. Similarly, the imprint process in the present embodiment includes a supply process (S101), a stamping process (S102), a curing process (S103), and a release process (S104). Since these processes are as described above, detailed description thereof will be omitted here. However, in FIG. 5, the stamping process (S102) starts the stamping process for starting the operation of relatively bringing the mold M and the substrate W closer (S102-1), and ends the stamping process for ending the operation (S102). -2). Similarly, in the release processing (S104), the release processing is started (S104-1) to start the operation of relatively separating the mold M and the substrate W, and the release processing is ended (S104) to end the operation. -2).

  In S201, the state of the substrate W before starting the imprint process is confirmed. For example, using the observation unit 9 or the like, it is checked whether or not particles (foreign matter, dust) and the like are attached to the substrate W.

  In S202, in the supply process (S101), the quality of the imprint process is determined based on the image captured by the observation unit 9 (the image sensor 9b). In the imprint apparatus 100, in order to reduce the time required to supply the resin R to the substrate W, the dispenser 11 dispenses the resin R droplets as shown in FIGS. 6 (a) and 6 (d). It has a configuration in which a plurality of discharge ports 61 for discharging are arranged in a line. In the supply process (S101), as shown in FIGS. 6B and 6E, while moving the substrate stage 2 in the scanning direction 62, the droplets of the resin R are discharged from the plurality of discharge ports 61 of the dispenser 11. The resin R is supplied to the substrate W by discharging.

  FIG. 6B shows an image captured by the image sensor 9b when the resin R is normally supplied to the substrate W. The resin R on the substrate to which the resin R is supplied by the dispenser 11 is shown. FIG. Referring to FIG. 6B, it can be confirmed that the droplets of the resin R are uniformly formed on the substrate, and that the droplets of the resin R to be supplied onto the substrate do not fall out.

  On the other hand, FIG. 6E shows that, when the supply of the resin R to the substrate W is not performed normally, for example, dust adheres to some of the plurality of discharge ports 61 of the dispenser 11. This is an image captured by the image sensor 9b when the droplets of the resin R cannot be ejected due to such reasons. Referring to FIG. 6E, it can be confirmed that the droplet of the resin R is dropped in the region 64 on the substrate corresponding to the discharge port 63 of the dispenser 11.

  Therefore, in the determination of the pass / fail of the imprint process in S202, it is determined whether or not the droplet of the resin R to be supplied onto the substrate is missing. Here, an image of a droplet of the resin R normally discharged from the dispenser 11 is used as a criterion for determining the quality of the imprint process. At this time, the image picked up by the image sensor 9b in the supply process (the arrangement of the droplets of the resin R) and the reference image obtained when the dispenser 11 normally discharges the resin R droplets (the resin R reference array).

  The determination of the quality of the imprint process in step S202 will be specifically described with reference to an example in which a variation in luminance of an image captured by the image sensor 9b is used. FIG. 6C is a graph showing the luminance along the broken line 65 of the image shown in FIG. 6B. In FIG. 6C, the luminance in the image is used on the vertical axis, and the position of the image is used on the horizontal axis. When the supply of the resin R to the substrate W is performed normally, as shown in FIG. 6C, the variation in luminance in the image captured by the image sensor 9b is reduced. FIG. 6F is a graph showing the luminance along the broken line 65 of the image (reference image) shown in FIG. In FIG. 6F, the vertical axis represents the luminance of the image, and the horizontal axis represents the position of the image. When the supply of the resin R to the substrate W is not performed normally, as shown in FIG. 6F, the brightness of the portion corresponding to the discharge port 63 of the dispenser 11 differs from the brightness of the other portions. I have. Therefore, in the supply process, the image captured by the image sensor 9b is compared with the reference image, and if the variation in the luminance of the image exceeds a predetermined range, the liquid of the resin R to be supplied onto the substrate is It can be determined that there is a drop in the droplet, that is, the imprint process is abnormal.

  In step S202, the quality of the imprint process is determined. If the imprint process is determined to be abnormal, the imprint process is stopped, for example, a defective product in which a part of the pattern on the substrate is missing. Can be prevented from being produced. Further, in S202, when the drop of the resin R to be supplied onto the substrate is detected as an abnormality of the imprint process, the process of removing dust attached to the dispenser 11 (discharge port) is automatically performed. The imprint processing can be continued by performing the processing in an appropriate manner.

  In S203, after the start of the stamping process (S102-1), the quality of the imprint process is determined based on the image captured by the observation unit 9 (the image sensor 9b). In the determination of the quality of the imprint process in S203, it is determined whether or not particles are attached to the substrate W.

  The determination of the quality of the imprint process in S203 will be specifically described. Here, the difference between the image captured by the image sensor 9b and the reference image after the start of the stamping process (S102-1) and the reference image is calculated using the difference image representing the difference in luminance for each pixel at the same position. It is determined whether or not particles are attached to the. As a criterion for judging the quality of the imprint process, an image in the case where the seal process is normally performed is used. The reference image is an image captured by the image sensor 9b after the start of the imprint process (S102-1) when the imprint process is normal.

  FIG. 7B is a differential image obtained when no particles are attached to the substrate W as shown in FIG. In the difference image shown in FIG. 7B, there is no large change, and the difference image includes only a low luminance value. This is because normal images are compared. FIG. 7D is a differential image obtained when the particles G are attached to the substrate W as shown in FIG. In the difference image shown in FIG. 7D, a large difference is generated between the reference image and the portion G ′ where the particles G attached to the substrate W are present, so that the difference image includes a high luminance value. I have. Therefore, if the difference image between the image captured by the image sensor 9b and the reference image after the start of the stamping process includes a luminance value exceeding a predetermined luminance value, the particles G adhere to the substrate W. That is, it can be determined that the imprint processing is abnormal.

  If the stamping process is continued in a state where the particles G adhere to the substrate W, the mold M and the particles G come into contact with each other, and the pattern P of the mold M may be damaged. Therefore, the determination as to whether or not the particles G are attached to the substrate W (S203) may be made at the timing when the mold M and the resin R on the substrate are in contact. Thus, it is possible to determine at an early stage that the particles G are attached to the substrate W (abnormality of the imprint process), and when the particles G are attached to the substrate W, the stamping process is interrupted. Thereby, damage to the mold M can be avoided. Further, not only the particles G attached to the substrate but also the particles attached to the mold M can be determined. As described above, the presence / absence of particles existing between the mold M and the substrate W can be determined (detected).

The force sensor 16 may be used to detect the timing at which the mold M and the resin R on the substrate are in contact with each other. FIG. 8 is a diagram for explaining the timing for determining whether the imprint processing is good or bad (S203). In FIG. 8, the output of the force sensor 16 disposed on the substrate chuck 1 (the force detected by the force sensor 16) is used on the vertical axis, and the time from the start of the stamping process to the end of the stamping process is used on the horizontal axis. doing. FIG. 8 shows a change in force (imprinting force) generated by the contact between the mold M and the resin R on the substrate in the imprinting process. Referring to FIG. 8, at the start of the stamping process, the output of the force sensor 16 is zero because the mold M and the resin R on the substrate are separated. When the stamping process proceeds and the mold M and the resin R on the substrate start to contact, the output of the force sensor 16 gradually increases. Therefore, at the timing when the force sensor 16 detects the force generated by the contact between the mold M and the resin R on the substrate, it may be determined whether or not the particles G are attached to the substrate W. In some cases, there is a time allowance between the time when the mold M comes into contact with the resin R on the substrate and the time when the mold M comes into contact with the particles G attached to the substrate W. In such a case, at the timing T ₁ to the output of the force sensor 16 exceeds the threshold value Th, determination may be performed whether the particles G in the substrate W is attached. The timing at which the mold M and the resin R on the substrate are in contact with each other can be detected using an image captured by the observation unit 9 (imaging element 9b) instead of the force sensor 16. For example, at the timing when the size (diameter) of the interference fringe imaged by the imaging element 9b becomes larger than the predetermined size PS, the presence or absence of particles existing between the mold M and the substrate W is determined.

  In S204, in parallel with S203, after the start of the stamping process (S102-1), the quality of the imprint process is determined based on the image captured by the observation unit 9 (imaging element 9b). As a criterion for determining the quality of the imprint process, an image of interference fringes captured by the image sensor 9b is used. In the determination of the quality of the imprint process in S204, the contact state between the mold M and the resin R on the substrate and the mutual posture between the mold M and the resin R are determined based on interference fringes as shown in FIG. I do. For example, as shown in FIG. 2B, information on at least one of the position and the roundness of the imaged interference fringes is obtained, and based on the information, the mold M is in contact with the resin R on the substrate in an inclined state. It is determined whether or not. Information on at least one of the position of the interference fringe and the roundness is obtained when the interference fringe imaged by the imaging device 9b after the start of the imprinting process and the mold M and the resin R on the substrate are normally contacted. It can be obtained by comparing with a reference interference fringe. The determination of the quality of the imprint process in S204 is the same as the determination of the quality of the imprint process (S206) performed after the start of the release process (S104-1) described later, and therefore, the detailed description here is omitted. Description is omitted.

  With reference to FIGS. 9 and 10 (a) to 10 (c), the timing for determining whether the imprint processing is good or not (S204) will be described. FIG. 9 shows an alignment signal generated by the alignment scope 5. In FIG. 9, the vertical axis indicates the intensity of the alignment signal, and the horizontal axis indicates the time from the start of the stamping process to the end of the stamping process.

FIG. 10 (a) shows a state of the mold M and the substrate W at the timing _{T A} shown in FIG. The alignment scope 5 detects the mold side mark 7 and the substrate side mark 6 by detecting the reflected light RL. Therefore, when the mold side mark 7 and the substrate side mark 6 are separated from each other as shown in FIG. 10A, the mold side mark 7 and the substrate side mark 6 are separated as shown in FIG. Since it cannot be detected, no alignment signal is generated.

FIG. 10 (b) shows a state of the mold M and the substrate W at a timing _{T B} shown in FIG. As shown in FIG. 10 (b), at the timing T _B, in contact with the resin R in the mold M and the substrate, the resin R are beginning to fill in the pattern P of the mold M. As the mold-side mark 7 and the substrate-side mark 6 approach each other, the mold-side mark 7 and the substrate-side mark 6 start to be detected, but while the resin R is being filled into the pattern P of the mold M, the resin R The reflected light RL fluctuates due to the movement of. Therefore, as shown in FIG. 9, the alignment signal generated by the alignment scope 5 varies.

FIG. 10 (c) shows a state of the mold M and the substrate W at a timing _{T C} shown in FIG. As shown in FIG. 10 (c), the timing T _C, the resin R on the substrate is sufficiently filled in the pattern P of the mold M, without the resin R moves, the reflected light RL is stabilized. Therefore, as shown in FIG. 9, the alignment signal generated by the alignment scope 5 is also stabilized.

Therefore, as shown in FIG. 9, at the timing T _D the alignment signal generated by the alignment scope 5 is stabilized at a pre-set period in PP, in contact with the resin R on the substrate in a state where the mold M inclined It is sufficient to determine whether or not there is. As described above, by using the alignment scope 5, it is possible to specify the timing at which the quality of the imprint process is determined (S204). However, the present invention is not limited to this. Instead of the alignment scope 5, as described above, the timing at which the quality of imprint processing is determined (S 204) may be specified using the force sensor 16. In this case, at the timing when the output of the force sensor 16 exceeds the threshold value or when the force sensor 16 detects the force generated by the contact between the mold M and the resin R on the substrate, the resin on the substrate is tilted. It is determined whether or not R is in contact.

In the stamping process, alignment between the mold M and the substrate W is performed based on the detection result of the alignment scope 5 during the AP shown in FIG. To determine the quality of the imprint process at timing T _C, when it is determined that the imprinting is abnormal, by stopping the imprint process is performed in vain alignment between the mold M and the substrate W Can be prevented.

  In S205, in parallel with S203 and S204, after the start of the stamping process (S102-1), the quality of the imprint process is determined based on the image captured by the observation unit 9 (the image sensor 9b). In the determination of the quality of the imprint process in S205, it is determined whether or not the resin R droplet to be supplied from the dispenser 11 onto the substrate is missing.

  In the imprint apparatus 100, in order to shorten the time required to supply the resin R to the substrate W, the dispenser 11 dispenses the droplet of the resin R as shown in FIGS. 14A and 14C. It has a configuration in which a plurality of discharge ports 61 for discharging are arranged in a line. In the supply process (S101), as shown in FIGS. 14B and 14D, while moving the substrate stage 2 in the scanning direction 62, the droplets of the resin R are discharged from the plurality of discharge ports 61 of the dispenser 11. The resin R is supplied to the substrate W by discharging.

  FIG. 14B is an image captured by the imaging element 9b during the stamping process when the supply of the resin R to the substrate W is normally performed. The state where the pattern P is filled is shown. FIG. 14B shows the timing of the interference fringes observed in the stamping process (FIG. 2) after the center of the interference fringes spreads over the entire surface of the mold M (pattern P) due to the progress of the stamping process. 9 shows interference fringes. Referring to FIG. 14B, it can be confirmed that there is no variation in the luminance of the pixels in the region corresponding to the mold M (pattern P), and there is no dropout of the resin R to be supplied onto the substrate.

  On the other hand, FIG. 14D shows an image captured by the image sensor 9b during the stamping process when the supply of the resin R to the substrate W is not performed normally. In addition, the case where the supply of the resin R to the substrate W is not performed normally means that, for example, dust adheres to some of the plurality of discharge ports 63 of the dispenser 11 and the resin R This is a case where droplets cannot be ejected. Referring to FIG. 14D, it can be confirmed that the brightness of the pixel is different in the area 64 on the substrate corresponding to the discharge port 63 of the dispenser 11 as compared with the other areas.

  FIGS. 15A and 15B are diagrams for explaining the interference fringes observed in FIG. 14D. FIG. 15A shows a gap between the mold M and the substrate W during the stamping process, and a state of filling the pattern P of the mold M with the resin R. FIG. 15B shows a part of an image captured by the image sensor 9b. Referring to FIG. 15B, in a region 121 where there is no dropout of the resin R droplets, the mold M and the resin R having a similar refractive index are in contact with each other. The reflectivity becomes very small. For this reason, the reflected light in the region 121 where there is no dropout of the resin R droplets is weakened, and as a result, a dark image is obtained in the imaging element 9b.

  On the other hand, in the region 122 where the droplets of the resin R are missing, a gap exists between the mold M and the resin R. For this reason, the reflected light from the mold M and the reflected light from the resin R interfere with each other, and as a result, a bright image is obtained on the imaging element 9b. In other words, a region where a gap exists between the mold M and the resin R becomes a bright image. Therefore, the dropout of the resin R droplet can be detected in an area larger than the size of one droplet of the actual resin R, so that the resolution is smaller than the resolution required for detecting one droplet of the resin R. The drop of the resin R droplets can be detected by the observation unit 9 (imaging element 9b) having a low resolution.

  As described above, it can be determined from FIG. 14D obtained by the imaging device 9b whether or not there is a drop of the resin R to be supplied from the dispenser 11 onto the substrate. In addition, as shown in FIG. 14 (d), the interference fringes include a case where one bright line is missing due to the dropping of one droplet, and a case where a plurality of droplets are missing. This includes the case where a plurality of light and shade lines (a plurality of lines) are repeated.

  As described above, in the determination of the quality of the imprint process in S205, it is determined whether or not the resin R droplet to be supplied from the dispenser 11 onto the substrate is missing. At this time, an image (interference fringe) captured by the image sensor 9b in the stamping process is compared with a reference image (reference interference fringe) obtained when the dispenser 11 normally discharges the droplet of the resin R. The determination of the quality of the imprint process in S205 will be specifically described using an example in which the presence or absence of a vertical streak (bright and dark line) in the scanning direction (moving direction) in the image captured by the image sensor 9b is used.

  FIG. 16 shows a difference image between the image shown in FIG. 14B and the image shown in FIG. Referring to FIG. 16, in the difference image, pixels having a difference become white, and pixels having no difference become dark. In the difference image, a boundary line 131 where the brightness of the pixel changes is extracted, and whether the boundary line 131 is parallel to the scanning direction 62, that is, whether the boundary line 131 approximates a straight line indicating the scanning direction 62 or not , The presence or absence of a vertical streak in the scanning direction is determined.

  In the present embodiment, it is also determined in S202 whether or not the liquid droplets of the resin R are missing. In S202, since the droplet of the resin R on the substrate is directly observed, as shown in FIG. 6B, in the image obtained by the imaging element 9b, the luminance of each pixel differs depending on the presence or absence of the droplet. ing. On the other hand, in S205, the stamping process is started and the interference fringes when the pattern P of the mold M is filled with the resin R are observed. Therefore, as shown in FIGS. 14B and 14D, Little change in luminance for each pixel. Therefore, as compared with S202, in S205, it is possible to allow the image sensor 9b to have a low resolution, and it is possible to detect a drop of the droplet of the resin R as a clear vertical streak.

Note that the timing of the determination of the quality of the imprint process (S205), as the timing T _D shown in FIG. 9, the resin R may be filled timing pattern P of the mold M. The region 64 (vertical streak) detected when there is a drop in the resin R droplet can be detected even during the filling of the resin R such that the interference fringe shown in FIG. 2 is obtained. Therefore, the timing for performing quality determination of imprint processing (S205) is not limited to the timing T _D shown in FIG. 9, the area 64 shown in FIG. 14 (d) may be any timing detectable.

In step S205, the quality of the imprint process is determined. If the imprint process is determined to be abnormal, the imprint process is stopped, and for example, a defective product in which a part of the pattern on the substrate is missing. Can be prevented from being produced.
Further, in S205, when the drop of the resin R to be supplied onto the substrate is detected as an abnormality of the imprint process, the process of removing dust attached to the dispenser 11 (discharge port) is automatically performed. The imprint processing can be continued by performing the processing in an appropriate manner.

  In S206, after the start of the release processing (S104-1), the quality of the imprint processing is determined based on the image captured by the observation unit 9 (the imaging element 9b). In the release step, as shown in FIG. 11A, when the mold M is separated from the cured resin R on the substrate in an inclined state, the pattern of the resin R formed on the substrate falls down or is damaged. Or

  Therefore, in the determination of the quality of the imprint process in S206, the mold M is separated from the cured resin R on the substrate in an inclined state based on interference fringes as shown in FIGS. 2B and 11B. It is determined whether or not it has been performed. As a criterion for determining the quality of the imprint process, an image of interference fringes captured by the image sensor 9b is used. Specifically, as shown in FIG. 11B, first, the position (Pos X, Pos Y) of interference fringes and the roundness (the ratio between Width and Height) are obtained. The position and roundness of the interference fringe are determined by the interference fringe imaged by the image sensor 9b after the start of the mold release process and the reference interference fringe obtained when the mold M and the resin R on the substrate are normally separated. Can be obtained by comparing If the position of the interference fringes or the roundness exceeds the threshold, the mold M is separated from the cured resin R on the substrate in an inclined state, that is, it is determined that the imprint processing is abnormal. . As described above, even when the state of the substrate W changes greatly in a short period of time, the quality of the imprint process can be determined with high accuracy by using the interference fringe captured by the image sensor 9b.

  With reference to FIGS. 12A to 12C, the timing for determining whether the imprint processing is good or not (S206) will be described. FIGS. 12A to 12C show images (interference fringes) captured by the image sensor 9b according to the elapse of time in the release processing. In the release processing, as described above, the mold M is deformed into a convex shape on the substrate side in order to reduce the release force that is a force for separating the mold M from the cured resin R on the substrate. Thereby, the cured resin R on the substrate is separated from the outer peripheral portion of the mold M, and peeling of the resin R from the substrate W can be prevented. Therefore, in the release process, as in the stamping process, a gap is generated between the mold M and the substrate W, and interference fringes as shown in FIGS. 12A to 12C are observed. Referring to FIGS. 12A to 12C, as the contact area between the mold M and the cured resin R on the substrate decreases, the size of the interference fringes gradually decreases. Therefore, at the timing when the size (diameter) of the interference fringe becomes smaller than the predetermined size PS, it is determined whether or not the mold M is separated from the cured resin R on the substrate in an inclined state.

  Generally, since the release processing is performed in a short time, it is difficult to specify the timing for determining whether or not the mold M is separated from the cured resin R on the substrate in an inclined state. On the other hand, in the present embodiment, the timing of determining whether or not the mold M is separated from the cured resin R on the substrate in an inclined state by using (the size of) the interference fringe imaged by the imaging element 9b. It is possible to specify.

  In S207, after the release processing, the quality of the imprint processing is determined based on the image captured by the observation unit 9 (the image sensor 9b). As a criterion for determining the quality of the imprint process, an image of interference fringes captured by the image sensor 9b is used. In the determination of the quality of the imprint process in S207, it is determined whether or not the pattern is normally formed on the substrate W, for example, whether or not the resin R is peeled from the substrate W.

  By separating the mold M from the cured resin R on the substrate, a resin R having a pattern corresponding to the pattern P of the mold M is formed on the substrate W. FIG. 13A shows an image picked up by the image pickup device 9b when the release step is performed normally. If the pattern P of the mold M is a periodic line-and-space pattern, as shown in FIG. 13A, the brightness is low at the portion of the resin R formed on the substrate W and the brightness is low at other portions. A high image is obtained. FIG. 13C illustrates an image captured by the imaging element 9b when the mold release process is not performed normally, for example, when the resin R is separated from the substrate W and adheres to the mold M. In this case, as shown in FIG. 13C, an image having a high luminance at the portion 71 where the resin R has peeled off is obtained.

  Therefore, the resin R is peeled off from the substrate W using a difference image representing a difference in luminance for each pixel at the same position between the image captured by the image sensor 9b and the reference image after the release processing. Determine whether or not. The reference image is an image captured by the image sensor 9b after the release processing when the imprint processing is normal.

  FIG. 13B is a differential image obtained when the resin R is not peeled off from the substrate W as shown in FIG. In the difference image shown in FIG. 13B, there is no large change, and the difference image includes only a low luminance value. This is because normal images are compared. FIG. 13D is a differential image obtained when the resin R is peeled off from the substrate W as shown in FIG. In the difference image shown in FIG. 13D, a large difference is generated between the reference image and the portion 72 where the resin R has peeled off, so that the difference image includes a high luminance value. Therefore, if the difference image between the image captured by the image sensor 9b and the reference image after the start of the release process includes a luminance value exceeding a predetermined luminance value, the resin R is peeled from the substrate W. That is, it can be determined that the imprint processing is abnormal.

  The determination of the quality of imprint processing using such a difference image is also effective when determining the quality of imprint processing for a substrate having a base on which a pattern has already been formed. In this case, it is necessary to prepare a reference image for each base.

  In the imprint apparatus 100 of the present embodiment, in each process of the imprint process, the quality of the imprint process can be correctly determined by grasping the state of the substrate W with high accuracy. Thereby, in the imprint apparatus 100, it is possible to suppress the influence of the abnormality of the imprint processing, and it is possible to improve the productivity.

  Further, in the imprint apparatus 100 of the present embodiment, the timing for determining the quality of the imprint process is specified using information from the alignment scope 5, the force sensor 16, and the observation unit 9. Thus, it is possible to specify a timing suitable for determining whether or not the imprint processing is good, instead of a timing for switching the imprint processing. Further, in the stamping process or the like, it is possible to determine the quality of the imprint process at different timings according to the state of the substrate W.

  In the present embodiment, the quality of the imprint process is determined in the supply process, the stamping process, and the release process, but the present invention is not limited to this. For example, the determination of the quality of the imprint process may be performed in at least two of the supply process, the stamping process, and the release process, or the determination of the quality of the imprint process may be performed in at least one of the supply process and the stamping process. May go. Also, the quality of the imprint process may be determined between the stamping process and the curing process or between the curing process and the release process.

  If it is determined that the imprint processing is abnormal, error processing corresponding to the abnormality is performed. For example, in S203, when it is determined that the particles G are attached to the substrate W, a process of removing the particles G is performed, or a process of storing the position on the substrate where the particles G are attached is performed. be able to. If the particles G cannot be removed, the imprint processing may be stopped, or the mold M may not be brought into contact with the particles G (a pattern may not be formed).

  In the present embodiment, the photo-curing method in which the resin is cured by irradiating ultraviolet rays (light) is described as an example of the resin curing method. However, the resin curing method is not limited to the light curing method, but may be a heat cycle method. In the thermal cycling method, a thermoplastic resin is heated to a temperature equal to or higher than a glass transition temperature to bring a mold into contact with the resin in a state of increasing fluidity, and the resin is cooled to cure the resin. Then, a pattern is formed on the substrate by separating the mold from the cured resin on the substrate.

  A method for manufacturing a device (a semiconductor device, a magnetic storage medium, a liquid crystal display element, or the like) as an article will be described. Such a manufacturing method includes a step of forming a pattern on a substrate (a wafer, a glass plate, a film-like substrate, or the like) using the imprint apparatus 100. Such a manufacturing method further includes a step of processing the substrate on which the pattern is formed. The processing step may include a step of removing a residual film of the pattern. Further, the method may include other well-known steps such as a step of etching the substrate using the pattern as a mask. 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 related art.

  Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

100: Imprinting device 9: Observation unit 9b: Image sensor 12: Control unit M: Mold W: Substrate

Claims (18)

An imprint apparatus for forming a pattern using a mold on an imprint material on a substrate,
An imaging unit for acquiring an image of at least one of the mold and the substrate,
A determination unit that determines the quality of the imprint process,
The imprint process includes a first step of supplying an imprint material on the substrate, and a second step of bringing the mold into contact with the imprint material on the substrate,
The determination unit is configured to position the substrate to which the imprint material is supplied with respect to the mold, and then perform the imprint process in the first process based on an image acquired through the mold by the imaging unit. Judge pass / fail regarding the first criterion, and judge pass / fail regarding the second criterion different from the first criterion of the imprint process in the second step , and at least during the imprint process , In a state where the mold is brought into contact with the substrate side in a state of being deformed into a convex shape on the substrate side, and in a state where the mold which has been deformed into the convex shape is brought back into contact with the imprint material in a state where it is returned to its original state. An imprint apparatus for determining whether the pass / fail is good while switching between the first reference and the second reference. The imprint process includes a third step of separating the mold from the cured imprint material on the substrate,
The determination unit may determine whether the imprint processing is good or bad with respect to a third criterion different from the first criterion and the second criterion, based on the image captured by the imaging unit in the third step. The imprint apparatus according to claim 1, wherein The imaging unit acquires an image including interference fringes of light reflected by the mold and light reflected by the substrate,
The imprint apparatus according to claim 1, wherein the determination unit determines whether the imprint processing is good or bad based on the interference fringes in the second step.   4. The imprint apparatus according to claim 3, wherein in the second step, the determination unit determines presence or absence of a foreign substance existing between the mold and the substrate based on the interference fringes. 5.   The determination unit is based on information on at least one of the position and roundness of the interference fringes included in the image acquired by the imaging unit, and based on the imprint material on the substrate in a state where the mold is inclined. The imprint apparatus according to claim 3, wherein it is determined whether or not there is contact. A dispenser configured to discharge droplets of the imprint material on the substrate,
The determination unit determines whether or not the droplet to be supplied from the dispenser onto the substrate is missing based on the interference fringes included in the image acquired by the imaging unit. The imprint apparatus according to claim 3, wherein   The determination unit compares the interference fringes included in the image acquired by the imaging unit with a reference interference fringe obtained when the droplet to be supplied from the dispenser onto the substrate has no omission. Detecting the presence or absence of a light and dark line generated in the moving direction of the substrate while the dispenser supplies the droplet, and determining whether or not the droplet to be supplied on the substrate has a dropout. The imprint apparatus according to claim 6, wherein   In the interference fringes included in the image acquired by the imaging unit, the determination unit determines whether the boundary of the interference fringes approximates a straight line parallel to the moving direction, and determines whether the interference fringes in the interference fringes are high or low. The imprint apparatus according to claim 7, wherein the presence or absence of a line is detected. Further comprising a force sensor for detecting a force generated by the contact between the mold and the imprint material on the substrate,
4. The imprint apparatus according to claim 3, wherein the determination unit determines whether the imprint processing is good or not at a timing when a force detected by the force sensor exceeds a threshold. 5. Further comprising a force sensor for detecting a force generated by the contact between the mold and the imprint material on the substrate,
4. The imprint apparatus according to claim 3, wherein the determination unit determines whether the imprint processing is good or bad at a timing when the force sensor detects the force. 5. An alignment detection unit that detects the mark formed on the mold and the mark formed on the substrate and generates an alignment signal,
4. The imprint according to claim 3, wherein the determination unit determines whether the imprint processing is good or not at a timing when an alignment signal generated by the alignment detection unit is stable within a preset period. 5. apparatus.   The determination unit determines whether the imprint processing is good or bad at a timing when the size of the interference fringes included in the image acquired by the imaging unit becomes larger than a predetermined size. The imprint apparatus according to claim 3. The imaging unit acquires an image including interference fringes of light reflected by the mold and light reflected by the substrate,
3. The imprint apparatus according to claim 2, wherein the determining unit determines whether the imprint processing is good or not based on the interference fringes in the third step. 4.   14. The imprint apparatus according to claim 13, wherein the determination unit determines the quality of the imprint process at a timing when the size of the interference fringes becomes smaller than a predetermined size. The first criterion or the second criterion is a criterion for determining the quality of droplets of the imprint material discharged from a discharge port provided in a supply unit that supplies the imprint material onto the substrate. The imprint apparatus according to claim 1, further comprising: An imprint apparatus for forming a pattern using a mold on an imprint material on a substrate,
An imaging unit for acquiring an image of at least one of the mold and the substrate,
A determination unit that determines the quality of the imprint process,
The imprint process includes a first step of supplying an imprint material on the substrate, a second step of bringing the mold into contact with the imprint material on the substrate, and a step of curing the imprint material on the substrate. A third step of separating the mold,
The determination unit is configured to position the substrate to which the imprint material is supplied with respect to the mold, and then perform the imprint process in the first process based on an image acquired through the mold by the imaging unit. The first criterion of the imprint processing in the second step, and the first criterion of the imprint processing in the third step, which is different from the first criterion of the imprint processing in the second step. And determining whether the third reference different from the second reference is acceptable, and at least during the imprint processing , contacting the imprint material with the mold deformed into a convex shape toward the substrate side. and state, in a state in which is contacted with the imprint material while undoing the mold is deformed to the convex shape, the first group Imprint apparatus and performs quality determination while switching between the third reference and the second reference. An imprint method for performing an imprint process of forming a pattern using a mold on an imprint material on a substrate,
The imprint process includes a first step of supplying an imprint material on the substrate, and a second step of bringing the mold into contact with the imprint material on the substrate,
The imprint method, based on an image obtained by imaging at least one of the mold and the substrate after positioning the substrate to which the imprint material is supplied with respect to the mold, in the first step Determining the acceptability of the imprint process with respect to a first criterion; determining the acceptability of the imprint process with respect to a second criterion different from the first criterion in the second step; at least during the imprint process, A state in which the mold is brought into contact with the imprint material in a state in which the mold is deformed to the substrate side in a convex shape, and a state in which the mold deformed in the convex shape is brought back into contact with the imprint material in a state in which the mold is restored. An imprint method , wherein the pass / fail judgment is made while switching between the first reference and the second reference. Forming a pattern on a substrate using the imprint apparatus according to any one of claims 1 to 16,
Processing the substrate on which the pattern is formed in the step,
A method for producing an article, comprising: