Patent Publication Number: US-11656547-B2

Title: Imprint apparatus, imprinting method, and product manufacturing method

Description:
BACKGROUND 
     Field of the Disclosure 
     The present disclosure relates to an imprint apparatus, an imprinting method, and a product manufacturing method. 
     Description of the Related Art 
     A known method for manufacturing a product such as a semiconductor device or a micro electro mechanical system (MEMS) device includes an imprinting method in which an imprint material on a substrate is molded using a mold. In the imprinting method, the imprint material is supplied onto the substrate, and the supplied imprint material is brought into contact with the mold (pressing). Then, after the imprint material is cured in a state where the imprint material is in contact with the mold, the mold is separated (released) from the cured imprint material to form a pattern of the imprint material on the substrate. 
     In such an imprinting method, the imprint material is irradiated with curing light such as ultraviolet light in a state where the imprint material fills a space between the mold and the substrate, so that the imprint material is cured. At that time, the imprint material needs to densely fill the space between the mold and the substrate so that the pattern of the mold can be reliably transferred. On the other hand, it is necessary to prevent the imprint material from protruding into an adjacent shot region, which is the outside of a pattern area formed in the mold. 
     Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2011-521438 discusses a method in which, when a mold is contacted with a polymerizable material (imprint material) being a photo-curing resin, the outside of a pattern area formed in the mold is irradiated with light to prevent the imprint material from being extruded outside the pattern area. 
     In an imprint apparatus, when the imprint material on the substrate is contacted with the mold, the imprint material fills the space between the mold and the substrate by spreading outward from the center of the pattern area of the mold (or the shot region of the substrate). Further, in the imprint apparatus, it is necessary to irradiate an outer peripheral portion of the pattern area of the mold with curing light at an appropriate timing to cure the imprint material that is about to protrude outside the shot region. This is because if a timing of light irradiation is too early, the imprint material may be cured more than necessary, and if the timing of light irradiation is too late, the imprint material is extruded outside the pattern area of the mold. Thus, the timing of light irradiation can be determined in advance. 
     However, spread of the imprint material when the imprint material fills the space between the mold and the substrate (i.e., extent to which the imprint material is extruded) varies depending on various conditions, such as surface conditions of the mold and the substrate, an amount of supply of the imprint material, and viscosity characteristics of the imprint material. Thus, the outer peripheral portion of the pattern area may not be irradiated with light at an appropriate timing. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the present invention, an imprint apparatus for forming a pattern of an imprint material on a substrate by using a mold including a pattern formation area, the imprint apparatus includes a detection unit configured to detect a contact state of the imprint material on the substrate with the mold, a light modulation element configured to control an intensity distribution of irradiation light irradiating the substrate, and a control unit configured to control a timing of irradiating the substrate with the irradiation light having the intensity distribution controlled by the light modulation element based on a detection result of the detection unit. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating an imprint apparatus. 
         FIG.  2    is a diagram illustrating an imprint apparatus according to a first exemplary embodiment. 
         FIG.  3    is a diagram illustrating an imprint apparatus according to a second exemplary embodiment. 
         FIG.  4    is a flowchart illustrating an imprinting process. 
         FIG.  5    is a diagram illustrating an imprint apparatus according to a third exemplary embodiment. 
         FIGS.  6 A,  6 B,  6 C, and  6 D  are diagrams illustrating detection areas and irradiated areas in a shot region. 
         FIGS.  7 A,  7 B,  7 C,  7 D,  7 E, and  7 F  are diagrams illustrating a method of manufacturing a product. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the present invention will be described below in detail with reference to the attached drawings. In each of the drawings, the same reference numerals are used to indicate identical members, and explanation is not repeated. 
     (Imprint Apparatus) 
       FIG.  1    is a diagram schematically illustrating a configuration of an imprint apparatus  100 . The configuration of the imprint apparatus  100  will be described with reference to  FIG.  1   . The imprint apparatus  100  brings an imprint material supplied onto a substrate into contact with a mold and applies curing energy to the imprint material to form a pattern of a cured product onto which a depression-protrusion pattern of the mold is transferred. 
     Axes are defined, as illustrated in  FIG.  1   , so that a plane on which a substrate  1  is placed is referred to as an XY plane, and a direction perpendicular to the XY plane is referred to as a Z-direction. The imprint apparatus  100  can form patterns in a plurality of shot regions formed on the substrate  1  by repeating an imprint process. A pattern formed on a mold  4  is transferred onto an imprint material supplied onto the substrate  1  to form, on a surface of the substrate  1 , an imprint material pattern corresponding to the pattern of the mold  4 . 
     Glass, ceramics, metal, semiconductor, resin, or the like is used for the substrate  1 , and a member made of a material different from the material of the substrate can be formed on the surface of the substrate  1  as necessary. More specifically, the substrate  1  includes a silicon wafer, a compound semiconductor wafer, quartz glass, and the like. 
     A substrate stage  2  can move the substrate  1  in an X-direction and a Y-direction and rotate the substrate  1  about a Z axis to move the entire surface of the substrate  1  under the mold  4 . The substrate stage  2  includes a displacement sensor  2   a  configured to detect a movement position. The substrate stage  2  can be moved to a desired position by using a drive mechanism such as a motor based on a detected value of the displacement sensor  2   a . A laser interferometer, an encoder, or the like can be used as the displacement sensor  2   a . A base frame  3  holds and guides the substrate stage  2 . 
     The mold  4  is used for molding the imprint material on the substrate  1 . The mold  4  can also be called a template or an original plate. The mold  4  has a polygonal (rectangular) outer shape, and has a pattern area  4   a  (pattern formation area) in which a pattern (depression-protrusion pattern) to be transferred onto the substrate  1  is formed. On a surface of the mold  4  facing the substrate  1 , the pattern area  4   a  (also referred to as a mesa part) protruding from a periphery is provided near the center. In the pattern area  4   a , the depression-protrusion pattern to be transferred onto the substrate  1 , such as a circuit pattern, is formed to have a three-dimensional shape. The mold  4  is made of a material such as quartz transmitting curing light  8   a.    
     The imprint apparatus  100  includes a mold holding unit  5  configured to hold the mold  4 , and a drive device  6  configured to move the mold  4  held by the mold holding unit  5  in a vertical direction and in a tilt direction. The mold holding unit  5  attracts a back surface of the mold  4  (surface on which the curing light  8   a  is incident) with a vacuum suction force or an electrostatic force to hold the mold  4 . The drive device  6  is fixed to a surface plate  7  of an apparatus main body, and performs operations of contacting the mold  4  with the imprint material supplied on the substrate  1  (pressing step) and releasing the mold  4  from the imprint material (releasing step). When the imprint apparatus  100  contacts the mold  4  with the imprint material, the imprint apparatus  100  may drive the mold  4  to press against the imprint material or may drive the substrate  1  so that the imprint material is pressed against the mold  4 . Further, the imprint apparatus  100  may move both the mold  4  and the substrate  1  to be brought into contact with each other. 
     An irradiation unit  8  irradiates the imprint material with the curing light  8   a  (e.g., ultraviolet light) through the mold  4  to cure the imprint material. If a material to be cured by irradiation with the ultraviolet light is used for the imprint material, the irradiation unit  8  is an ultraviolet light generation device. The irradiation unit  8  includes a shutter unit  8   b  configured to control an irradiation timing. 
     The imprint apparatus  100  includes a supply unit  9  (also referred to as a dispenser). The supply unit  9  is disposed near the mold holding unit  5 , and supplies (applies) an uncured imprint material (also referred to as uncured resin) to the substrate  1 . The imprint material according to the present exemplary embodiment is an ultraviolet curable resin material having a property of being cured by ultraviolet light irradiation as irradiation of the curing light  8   a . The imprint material is selected based on various information such as information on a manufacturing process of the target semiconductor device. The amount of supply of the imprint material from the supply unit  9  is determined based on a thickness (residual layer thickness) and a density of the pattern of the imprint material to be formed on the substrate  1 . The supply unit  9  may be provided outside the imprint apparatus  100 . In such a case, the imprint material is supplied onto the substrate  1  in advance outside the imprint apparatus  100 , and the substrate  1  supplied with the imprint material is subjected to a mold pressing process and a mold releasing process inside the imprint apparatus. A pattern of the imprint material is formed on the substrate  1 . 
     A curable composition (sometimes referred to as an uncured resin) to be cured when curing energy is applied is employed as the imprint material. An electromagnetic wave, heat, or the like is employed as the curing energy. An example of the electromagnetic wave includes light such as infrared light, visible light, and ultraviolet light, whose wavelength is selected from a range of 10 nm or more and 1 mm or less. 
     The curable composition is a composition cured by light irradiation or by heating. The photocurable composition cured by light irradiation contains at least a polymerizable compound and a photopolymerization initiator, and may additionally contain a non-polymerizable compound or a solvent as necessary. The non-polymerizable compound is at least one selected from the group consisting of a sensitizer, a hydrogen donor, an internal mold release agent, a surfactant, an antioxidant, and a polymer component. 
     The imprint material can be applied onto the substrate  1  in a film form by using a spin coater or a slit coater. Further, the imprint material may be applied onto the substrate  1  in a form of droplets, or in a form of islands formed from connection of a plurality of droplets, or in a form of film by a liquid ejection head. The imprint material has viscosity (viscosity at 25° C.) of, for example, 1 mPa·s or more and 100 mPa·s or less. 
     The imprint apparatus  100  includes a mark measurement optical system (measurement unit)  10  configured to measure an alignment mark formed on the substrate  1  and an alignment mark formed on the mold  4 . The mark measurement optical system  10  is also called an alignment scope, and includes a lens, an illumination system, and a detection sensor (image pickup element) inside. The mark measurement optical system  10  detects the alignment marks formed on the substrate  1  and the mold  4  to measure an amount of positional deviation of the substrate  1  and the mold  4 . The alignment scope can measure relative positions of the mold  4  and the substrate  1  from the amount of positional deviation of the alignment marks. The imprint apparatus  100  can move at least one of the substrate stage  2  and the mold holding unit  5  by the measured amount of positional deviation to correct the positions to align the substrate  1  and the mold  4 . 
     A control unit  11  includes a computer including a central processing unit (CPU) and a memory, and controls components of the imprint apparatus  100  based on a program stored in the memory. The control unit  11  controls operation and adjustment of the components of the imprint apparatus  100  to control the imprint process of forming a pattern on the substrate  1 . The control unit  11  can perform positioning of the substrate stage  2  (substrate  1 ) based on a measurement value from the displacement sensor  2   a . The control unit  11  can be provided in the imprint apparatus  100  or separately from the imprint apparatus  100  to control the components remotely. 
     An imprint apparatus according to a first exemplary embodiment will be described with reference to  FIG.  2   .  FIG.  2    is a diagram schematically illustrating the imprint apparatus  100  including a detection unit and a partial irradiation mechanism  200 . The partial irradiation mechanism  200  irradiates a shot region on the substrate  1  with light in a frame shape based on a detection result of the detection unit.  FIG.  2    also schematically illustrates a configuration and arrangement of the partial irradiation mechanism  200  provided in the imprint apparatus  100 . In  FIG.  2   , the same reference numerals are used to indicate the same components as those of  FIG.  1   , and explanation thereof is not repeated. 
     The partial irradiation mechanism  200  can irradiate a shot region  25  with light in a frame shape. The shot region  25  serves as a processing target formed in advance on the substrate  1  carried into the imprint apparatus  100 . When the pattern area  4   a  of the mold  4  and an imprint material  19  supplied onto the shot region  25  are brought into contact, it is possible to prevent the imprint material  19  from protruding from the pattern area  4   a.    
     The partial irradiation mechanism  200  includes a light source  20  configured to emit irradiation light  23  to cure the imprint material  19  around the shot region  25  (around the pattern area  4   a ) formed on the substrate  1  or to increase viscosity of the imprint material  19 . The partial irradiation mechanism  200  also includes a light modulation element  21  configured to adjust an irradiation amount, an irradiated area, and an intensity distribution of the irradiation light  23  with which the substrate  1  is to be irradiated, and an optical element  26  configured to reflect the irradiation light  23  so that the adjusted irradiation light  23  travels to the surface of the substrate  1 . 
     The light source  20  emits light having a wavelength for curing the imprint material  19  or increasing the viscosity of the imprint material  19 . The light modulation element  21  can emit light at a desired position of the irradiation light  23  from the light source  20  toward the surface of the substrate  1  to form a desired irradiated area (intensity distribution) in the shot region  25 . Examples of the light modulation element  21  include a digital micromirror device (DMD), a liquid crystal display (LCD) device, and a liquid crystal on silicon (LCOS) device. The use of the light modulation element  21  makes it possible to freely set the irradiated area and the intensity distribution of the irradiation light  23  with which the substrate  1  is to be irradiated. In the digital micromirror device, a plurality of mirror elements is arranged on a reflection surface. A face direction of each of the mirror elements is individually adjusted to change a distribution of the irradiation amount of the irradiation light  23 . The control unit  11  of the imprint apparatus  100  according to the present exemplary embodiment controls operation of at least the partial irradiation mechanism  200 . 
     Next, the imprint process performed by the imprint apparatus  100  will be described. First, a substrate transport unit (not illustrated) transports the substrate  1  to the substrate stage  2  to place and fix the substrate  1  on the substrate stage  2 . Subsequently, the substrate stage  2  is moved to a supply position of the supply unit  9 . Then, the supply unit  9  supplies the imprint material  19  to the predetermined shot region  25  of the substrate  1 , which is a supply step. Next, the substrate stage  2  is moved so that the shot region  25  of the substrate  1  supplied with the imprint material  19  is positioned immediately below the pattern area  4   a  of the mold  4 . Next, the drive device  6  of the mold holding unit  5  is driven to bring the mold  4  into contact with the imprint material  19  supplied on the substrate  1  (pressing step). 
     When the mold  4  contacts the imprint material  19 , the imprint material  19  fills the mold  4  along the depression-protrusion pattern formed in the pattern area  4   a  by the contact with the mold  4 . At this time, the partial irradiation mechanism  200  is used to irradiate a region along an outer periphery of the pattern area  4   a  with the irradiation light  23  to prevent the imprint material  19  from protruding outside the pattern area  4   a.    
     In the imprint apparatus  100  according to the first exemplary embodiment, the mark measurement optical system  10  is employed as the detection unit to determine an irradiation timing of the irradiation light  23  by the partial irradiation mechanism  200 . If the mark measurement optical system  10  detects a contact state between the mold  4  and the imprint material  19  during the pressing step, the partial irradiation mechanism  200  irradiates the substrate  1  with the irradiation light  23 . The mark measurement optical system  10  can move to detect the contact state at any location in the shot region  25  during the pressing step. 
     In the state where the mold  4  and the imprint material  19  are in contact, the imprint apparatus  100  detects the marks formed on the substrate  1  and the mold  4  by the mark measurement optical system  10 , and aligns the pattern area  4   a  of the mold  4  and the shot region  25  of the substrate  1  based on a detection result. After the filling of the depression-protrusion pattern of the pattern area  4   a  with the imprint material  19  and the alignment between the mold  4  and the substrate  1 , the irradiation unit  8  emits the curing light  8   a  toward the back surface (upper surface) of the mold  4 , which is a curing step, to cure the imprint material  19  by the curing light  8   a  transmitted through the mold  4 . After the imprint material  19  is cured, the imprint apparatus  100  widens a space between the mold  4  and the substrate  1  to release the mold  4  from the cured imprint material  19  (releasing step). Thus, the depression-protrusion pattern of the pattern area  4   a  formed on the mold  4  is transferred onto the imprint material  19  on the substrate  1 . 
     An imprint apparatus  100  according to a second exemplary embodiment will be described with reference to  FIG.  3   .  FIG.  3    is a diagram schematically illustrating the imprint apparatus  100  including the detection unit and the partial irradiation mechanism  200 . The partial irradiation mechanism  200  irradiates a shot region on the substrate  1  with light in a frame shape based on a detection result of the detection unit.  FIG.  3    also schematically illustrates a configuration and arrangement of the partial irradiation mechanism  200  provided in the imprint apparatus  100 . In the imprint apparatus  100  according to the second exemplary embodiment, an observation unit  30  is employed as the detection unit to determine an irradiation timing of the irradiation light  23  by the partial irradiation mechanism  200 . In  FIG.  3   , the same reference numerals are used to indicate the same components as those of  FIGS.  1  and  2   , and explanation thereof is not repeated. 
     In the present exemplary embodiment, a high-power laser light source  201  is used as the light source  20  of the partial irradiation mechanism  200 . Since the partial irradiation mechanism  200  needs to increase the viscosity of the imprint material  19  (cure the imprint material  19 ), the high-power laser light source  201  is employed. The irradiation light  23  from the laser light source  201  is reflected by a mirror  203 , and illuminates the light modulation element  21  (a micromirror array  205  in the present exemplary embodiment) using an optical system  204 . A reflection surface of the micromirror array  205  and the surface of the substrate  1  are set to have a substantially conjugate relationship using an optical system  206  and an optical system  210 . Accordingly, if the control unit  11  controls each mirror of the micromirror array  205 , a target illuminance distribution can be formed on the surface of the substrate  1  (shot region  25  of the substrate  1 ). Here, a case will be described where a frame-like illuminance distribution (irradiated area) is formed along the outer periphery of the shot region  25  (or the pattern area  4   a ). The partial irradiation mechanism  200  may increase the viscosity of the imprint material  19  without curing the imprint material  19  to reduce the extrusion of the imprint material  19  from the pattern area  4   a  (shot region  25 ). 
     In the imprint apparatus  100  according to the present exemplary embodiment, the observation unit  30  is provided to detect a contact state (filling degree) between the imprint material  19  supplied to the shot region  25  and the pattern area  4   a  of the mold  4 . The observation unit  30  illuminates the surface of the substrate  1  with light from a light source  216 , and forms an image of light from the substrate  1  and the pattern area  4   a  of the mold  4  on a surface of a sensor  215  through an optical system  214  and the optical system  210 . The observation unit  30  can capture an image of the entire shot region  25  and can detect how a contact region between the pattern area  4   a  and the imprint material  19  expands from the vicinity of the center of the shot region  25  toward the outer periphery. 
     The irradiation unit  8  according to the present exemplary embodiment employs a high-pressure mercury lamp  213  as a light source. Light (curing light) from the high-pressure mercury lamp  213  is formed by an optical system  212  and the optical system  210  to illuminate the surface of the substrate  1 . 
     It is difficult to dispose the mark measurement optical system  10  immediately above the mold  4  while the mark measurement optical system  10  avoids interference with light (curing light) from the irradiation unit  8  and with the supply unit  9 . Thus, the imprint apparatus  100  according to the present exemplary embodiment includes a relay lens optical system  40  configured to form an image of the surface of the substrate  1  onto an imaging surface  217 . The relay lens optical system  40  is an equal magnification imaging optical system in the present exemplary embodiment, and the optical systems  210  are symmetrically arranged, and optical systems  211  are symmetrically arranged. The mark measurement optical system  10  detects a mark formed on the substrate  1  or a mark formed on the mold  4  that are imaged on the imaging surface  217  by the relay lens optical system  40 . 
     Here, the light sources of the irradiation unit  8  and the partial irradiation mechanism  200  need to emit light having a wavelength capable of curing the imprint material  19 . However, it is preferable that the light sources used for the observation unit  30  and the mark measurement optical system  10  emit light that does not cure the imprint material  19 . In the present exemplary embodiment, the irradiation unit  8  uses light having a wavelength of 380 nm or less (curing light  8   a ), and the partial irradiation mechanism  200  uses light having a wavelength of 390 nm to 410 nm (irradiation light  23 ). The observation unit  30  uses light having a wavelength of 410 nm to 490 nm, and the mark measurement optical system  10  uses light having a wavelength of 500 nm or more. The optical systems having such functions share a plurality of optical systems by a light combining unit. 
     The light combining unit employs a method using a mirror in which a transmittance and a reflectance are different in ratio, and a method using a dichroic mirror having a characteristic that the transmittance and the reflectance are different for each wavelength. In the case of using the mirror, part of light is used, resulting in a reduced efficiency. The dichroic mirror can separate light for each wavelength. However, it is necessary to have a margin in a wavelength band in consideration of manufacturing tolerance. In the present exemplary embodiment, a mirror  207  is employed as the light combining unit for light from the observation unit  30  and the partial irradiation mechanism  200 . A dichroic mirror  208  is employed as a light combining unit for light from the irradiation unit  8  and the observation unit  30  or the partial irradiation mechanism  200 . Dichroic mirrors  209  are employed as a light combining unit for light from the irradiation unit  8  and the mark measurement optical system  10  (relay lens optical system  40 ). 
     Whereas the high-power laser light source  201  is employed as the light source of the partial irradiation mechanism  200 , the observation unit  30  does not require light with high illuminance. For this reason, if the laser light source  201  is turned on, the light reflected by the substrate  1  passes through the mirror  207  and is detected as stray light by the sensor  215  of the observation unit  30 . This, a shutter  202  is provided so that the light from the partial irradiation mechanism  200  and the observation unit  30  do not become stray light. 
     (Imprinting Process) 
     Here, a sequence of an imprinting process in the present exemplary embodiment will be described with reference to a flowchart illustrated in  FIG.  4   . The imprint apparatus  100  repeats the flow of the imprinting process illustrated in  FIG.  4    until the imprint process is completed for all the plurality of shot regions formed on the substrate  1 . 
     In step S 1 , at a start of the imprinting process, the imprint material is supplied to a shot region to be processed of the substrate  1  held on the substrate stage  2  by using the supply unit  9 . Then, the shot region supplied with the imprint material is placed under the pattern area  4   a  of the mold  4 . 
     In step S 2 , a mold pressing process is performed in which the imprint material  19  supplied onto the substrate  1  and the pattern area  4   a  of the mold  4  are brought into contact with each other. At this time, the mold  4  may be moved close to the substrate  1  to contact the imprint material  19 , or the substrate  1  may be moved close to the mold  4  to bring the imprint material  19  and the pattern area  4   a  into contact with each other. Alternatively, both the substrate  1  and the mold  4  may be moved close to each other to bring the imprint material  19  and the pattern area  4   a  into contact with each other. 
     In step S 2 , the pattern area  4   a  of the mold  4  and the imprint material  19  can be brought into contact with each other from the vicinity of the center of the shot region  25  in a state where the pattern area  4   a  is deformed into a protruded shape toward the substrate  1 . 
     In step S 3 , filling of the pattern area  4   a  with the imprint material  19  is started. In step S 3 , the imprint material  19  contacting the pattern area  4   a  from the vicinity of the center of the shot region  25  in step S 2  starts to spread toward the periphery of the shot region  25 . 
     In step S 4 , the detection unit detects a contact state between the pattern area  4   a  and the imprint material  19 . The mark measurement optical system  10 , the observation unit  30 , or a leak sensor can be employed as the detection unit. The leak sensor detects a change in a refractive index depending on whether there is a liquid, from multiple points. 
     In step S 5 , partial irradiation is started using the partial irradiation mechanism  200  based on the detection result of the contact state by the detection unit. In this way, the imprint apparatus  100  according to the present exemplary embodiment can adjust the irradiation timing of the irradiation light  23  based on the detection result of the contact state by the detection unit. In the partial irradiation in the present exemplary embodiment, a case will be described where a frame-shaped irradiated area is formed in an area along the outer periphery of the pattern area  4   a  (shot region  25 ) to prevent the imprint material from protruding from the shot region  25 . The partial irradiation timing is to be within the time from the start of mold pressing to the start of irradiation for a curing process, and the irradiated area refers to an area to be irradiated with light around the pattern area  4   a . Further, an irradiation amount refers to an amount of light energy per unit area (e.g., W/m 2 ) of the irradiated area. 
     In step S 6 , the substrate  1  and the mold  4  are aligned, and the entire shot region  25  is irradiated with the curing light  8   a  from the irradiation unit  8  in a state where the pattern area  4   a  and the imprint material  19  on the shot region  25  are in contact with each other (curing process). The substrate  1  and the mold  4  are aligned by the mark measurement optical system  10  detecting light from a mark formed on the substrate  1  and a mark formed on the mold  4 . The irradiation of the curing light  8   a  is desirably performed after a relative positional deviation between the substrate  1  and the mold  4  reaches a target distance or less. The irradiation unit  8  irradiates the entire shot region  25  with the curing light  8   a , and thus, the imprint material  19  on the substrate  1  is cured. 
     In step S 7 , the mold releasing process is performed. In the mold releasing process, after the imprint material  19  is cured, the pattern area  4   a  of the mold  4  is separated from the cured imprint material  19  by widening the space between the substrate  1  and the mold  4 . The mold  4  is lifted by the drive device  6  to separate the mold  4  from the cured imprint material  19 . In the mold releasing process, the substrate  1  may be lowered to separate the cured imprint material  19  from the pattern area  4   a  of the mold  4 , or both the mold  4  and the substrate  1  may be driven to separate the pattern area  4   a  of the mold  4  and the cured imprint material  19  from each other. 
     In step S 8 , it is determined whether there is a shot region (unprocessed shot region) to be subjected to the imprint process next, among the plurality of shot regions formed on the substrate  1 . In step S 8 , if it is determined that there is the shot region to be subjected to the imprint process next (YES in step S 8 ), the processing returns to step S 1  to perform the imprint process of steps S 1  to S 7  on the next shot region. In step S 8 , if it is determined that there is no shot region to be subjected to the imprint process next (NO in step S 8 ), the imprint process ends, and the substrate  1  on which the pattern is formed is taken out from the imprint apparatus  100 . 
     Partial irradiation process in step S 5  in the present exemplary embodiment is to adjust the irradiation timing based on the detection result of the contact state in step S 4 . Thus, the conditions of the irradiated area and irradiation amount for partial irradiation are obtained in advance to be set as optimum conditions based on the size of the pattern area  4   a , the size of the shot region  25 , the type of the imprint material  19 , and the dimensions of the imprint material  19  formed on the substrate  1 . Further, if the optimum conditions differ depending on a position of the shot region  25  on the substrate  1 , the conditions may be obtained for each shot region  25 . Even if the imprint material  19  changes, there may be no change in the optimum conditions, or the optimum conditions may be obtained from past results without a prior test. 
     In the imprint apparatus  100  according to the present exemplary embodiment, a detection unit configured to detect a contact state between the mold  4  and the imprint material  19  on the substrate  1  is provided. Thus, a timing of irradiating the substrate  1  with the irradiation light whose intensity distribution is controlled can be controlled in real time. In the imprint apparatus  100 , the observation unit  30  serving as the detection unit detects the contact state between the mold  4  and the imprint material  19 , and the control unit  11  adjusts the timing of irradiation light from the partial irradiation mechanism  200  based on the detection result. For example, the partial irradiation can be started when a contact area between the mold  4  and the imprint material  19  whose images are captured by the observation unit  30  reaches a predetermined value, or the partial irradiation can be started when a predetermined position in the shot region  25  contacts the mold  4 . The timing of irradiating light from the partial irradiation mechanism  200  is adjusted by controlling ON/OFF of the laser light source  201  serving as a light source, controlling opening/closing of the shutter  202 , or controlling the reflection surface of the micromirror array  205  serving as a light modulation element. 
     As described above, the timing of the partial irradiation can be controlled depending on the contact state based on the detection result of the detection unit, thereby making it possible to prevent the protrusion of the imprint material  19  from the shot region  25  (pattern area  4   a ) depending on the contact state. 
     An imprint apparatus  100  according to a third exemplary embodiment will be described with reference to  FIG.  5   .  FIG.  5    is a diagram schematically illustrating the imprint apparatus  100  including the detection unit and the partial irradiation mechanism  200 . The partial irradiation mechanism  200  irradiates a shot region on the substrate  1  with light in a frame shape based on a detection result of the detection unit. T  FIG.  5    also schematically illustrates a configuration and arrangement of the partial irradiation mechanism  200  provided in the imprint apparatus  100 . In the imprint apparatus  100  according to the third exemplary embodiment, an observation unit  50  is employed as the detection unit to determine an irradiation timing of the irradiation light  23  by the partial irradiation mechanism  200 . In  FIG.  5   , the same reference numerals are used to indicate the same components as those of  FIGS.  1  to  3   , and explanation thereof is not repeated. 
     The imprint apparatus  100  according to the third exemplary embodiment includes the observation unit  50  configured to always observe a shot region during the imprint process. Thus, the imprint apparatus  100  can provide the partial irradiation mechanism  200  configured to perform control in real time. 
     It is necessary for the observation unit  50  to be used simultaneously with the irradiation unit  8 , the mark measurement optical system  10 , and the partial irradiation mechanism  200 . Thus, a light source that emits light having a wavelength of 430 nm to 490 nm is employed as a light source  303  of the observation unit  50  of the imprint apparatus  100  according to the third exemplary embodiment. Since wavelength bands used by the observation unit  50  and the partial irradiation mechanism  200  are different from each other, a dichroic mirror  301  can be employed as a light combining unit for the two optical systems. Further, a wavelength filter  302  is formed in the observation unit  50  to prevent light other than the light from the light source  303  of the observation unit  50  from entering the sensor  215 . The wavelength filter  302  may include a short wavelength cut filter that does not transmit light having a wavelength of less than 430 nm, a long wavelength cut filter that does not transmit light having a wavelength of more than 490 nm, or both the short wavelength cut filter and the long wavelength cut filter. 
     In the partial irradiation according to the present exemplary embodiment, the observation unit  50  observes spread of contact between the pattern area  4   a  and the imprint material  19 , and the partial irradiation mechanism  200  (micromirror array  205 ) is controlled based on an observation result. A method of controlling the partial irradiation mechanism  200  will be described below. 
       FIGS.  6 A,  6 B,  6 C, and  6 D  are diagrams illustrating examples of control of the micromirror array  205  provided in the partial irradiation mechanism  200 . More specifically,  FIGS.  6 A to  6 D  illustrate the shot region  25  (pattern area  4   a ) as viewed from above (+Z direction). As illustrated in  FIGS.  6 A to  6 D , the shot region  25  typically has a rectangular shape. 
     As illustrated in  FIG.  6 A , detection areas  501  to  504  are set corresponding to four sides of the shot region  25 . For each of the detection areas  501  to  504 , a contact state between the pattern area  4   a  of the mold  4  and the imprint material  19  on the shot region  25  is detected by the detection unit. With regard to the method of controlling the partial irradiation mechanism  200 , control of the light modulation element  21  by the control unit  11  will be described. In the third exemplary embodiment, the observation unit  50  is employed as the detection unit, and the micromirror array  205  is employed as the light modulation element. An image  500  illustrated in  FIG.  6 A  is an image obtained by the sensor  215  of the observation unit  50 . When filling of the pattern area  4   a  with the imprint material  19  described in step S 3  of  FIG.  4    is started, intensity of light from the substrate  1  and the mold  4  changes depending on the contact state between the mold  4  and the imprint material  19 . Accordingly, intensity of light detected by the sensor  215  of the observation unit  50  also changes. 
     A control map  510  illustrated in  FIG.  6 B  indicates an intensity distribution of irradiation light with which the substrate  1  is irradiated. In the present exemplary embodiment, a frame-shaped area along the outer periphery of the shot region  25  is irradiated with light. As illustrated in  FIG.  6 B , the frame-shaped area (irradiated areas  511  to  514 ) along the outer periphery of the shot region  25  is selectively irradiated with light, and thus, the imprint material  19  can be prevented from protruding from the shot region  25 . For the control map  510  illustrated in  FIG.  6 B , the irradiated area, a light amount, and a timing of the irradiation light are controlled by the micromirror array  205 . 
     The imprint apparatus  100  according to the present exemplary embodiment monitors changes in the light intensity detected by the sensor  215  at four places of the detection area  501 , the detection area  502 , the detection area  503 , and the detection area  504  in the image  500  captured by the observation unit  50 . If a change in the light intensity in any of the detection areas  501  to  504  reaches a threshold value or more after the filling with the imprint material  19  is started, the control unit  11  of the imprint apparatus  100  controls the partial irradiation mechanism  200  so that the irradiated area indicated in the control map  510  is irradiated with the irradiation light. 
     If changes in the light intensity detected in the detection areas  501  to  504  are detected in different timings, the area to be irradiated with the irradiation light can be controlled for each of the detection areas. The detection area  501  corresponds to the irradiated area  511 , the detection area  502  corresponds to the irradiated area  512 , the detection area  503  corresponds to the irradiated area  513 , and the detection area  504  corresponds to the irradiated area  514 , respectively. By detecting the change in the light intensity in each of the detection areas  501  to  504 , the corresponding micromirror array  205  can be controlled so that the corresponding irradiated area is irradiated with light. This makes it possible to irradiate the substrate  1  with the irradiation light in timing suitable for the contact state between the imprint material  19  and the pattern area  4   a , even if the contact state between the imprint material  19  and the mold  4  is different for each of the sides of the shot region  25 . This can prevent the imprint material  19  from protruding from the shot region  25 . 
     Further, as illustrated in  FIG.  6 C , in the image  500  indicating the shot region  25 , a detection area  520  being a collection of the detection areas (pixels) may be provided to correspond to the entire periphery of the shot region  25 . The timing of partial irradiation for preventing the imprint material  19  from being extruded cannot be uniquely determined because the timing is affected by a surface condition of the substrate  1  and characteristics of the imprint material  19 . Accordingly, the imprint material  19  cannot be prevented from being extruded stably. 
     Thus, the micromirror array  205  corresponding to an irradiated area  530  of the control map  510  illustrated in  FIG.  6 D  is controlled depending on the change in the light intensity in each of the detection areas (each of the pixels) in the detection area  520 . Such a large number of the detection areas (pixels) makes it possible not only to detect a contact state in each of the detection areas, but also to measure a filling speed at a portion between two different detection areas. In the example illustrated in  FIGS.  6 C and  6 D , the large number of the detection areas (pixels) makes it possible to control the extrusion of the imprint material  19  in the irradiated area  530  corresponding to the detection areas, but it is necessary to perform image data processing and calculation processing in a short time. For this reason, the observation unit  50  is required to have high-performance image processing capability. Accordingly, the observation unit  50  may include equipment such as an edge computing system, a graphics processing unit (GPU), a field-programmable gate array (FPGA) (reconfigurable hardware integrated circuit), and a dedicated processor. 
     Similar to the imprinting process illustrated in  FIG.  4   , in an imprinting process according to the present exemplary embodiment, the filling is started in step S 3 , and then a contact state in a detection area of the observation unit  50  serving as a detection unit is detected in step S 4 . In step S 5 , the timing of partial irradiation by the partial irradiation mechanism  200  is controlled based on the detection result in the detection area of the observation unit  50 . At this time, a filling speed with the imprint material  19  at each position in the detection area of the observation unit  50  may be calculated, and the irradiation timing of the irradiation light in the irradiated area  530  may be calculated from the calculated speed to control the partial irradiation mechanism  200 . While it is necessary to perform high-speed image processing and calculation processing from the start of filling to the partial irradiation, the actual spread of the imprint material  19  is reflected on irradiation conditions, and thus, the extrusion of the imprint material  19  can be reduced at each position of the outer periphery of the shot region  25 . 
     In the above description, the imprint apparatus employs an imprinting method of curing the imprint material  19  using the photo-curing method. However, the exemplary embodiments are not limited to using the photo-curing method, and alternatively, a method of curing the imprint material  19  with heat may be employed. In the photo-curing method, an ultraviolet curable resin is used. The resin is irradiated with ultraviolet light to cure the resin in a state where the mold is pressed against the substrate through the resin, and then the mold is released from the cured resin, to form a pattern. In the exemplary embodiments, ultraviolet light is employed as the curing light. However, a wavelength of the light can be appropriately determined to suit the imprint material  19  supplied onto the substrate  1 . On the other hand, in the curing method with heat, a thermoplastic resin is heated to the glass transition temperature or more, the mold is pressed against the substrate through the resin in a state where the fluidity of the resin is increased, the resin is cooled, and then the mold is released from the resin, to form a pattern. 
     (Method of Manufacturing Product) 
     The pattern of a cured product formed by using the imprint apparatus is employed permanently on at least part of various products, or temporarily in manufacturing various products. The products include an electric circuit element, an optical element, a micro electro mechanical system (MEMS) device, a recording element, a sensor, and a mold. Examples of the electric circuit element include a volatile or non-volatile semiconductor memory such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a flash memory, and a magnetoresistive random access memory (MRAM), and a semiconductor device such as a large scale integration (LSI), a charge-coupled device (CCD), an image sensor, and an FPGA. An example of the mold includes an imprint mold. 
     The pattern of the cured product is used as it is as at least part of a product such as the above-mentioned products, or temporarily used as a resist mask for the product. The resist mask is removed after etching, ion implantation, or the like in a processing step for a substrate. 
     Next, a specific method of manufacturing the product will be described. As illustrated in  FIG.  7 A , a substrate  1   z  such as a silicon wafer on which a material to be processed  2   z  such as an insulator is formed is prepared. Then, an imprint material  3   z  is applied on a surface of the material to be processed  2   z  by an inkjet method or the like. Here, a state is illustrated in which the imprint material  3   z  in a form of a plurality of droplets is applied on the substrate. 
     As illustrated in  FIG.  7 B , an imprint mold  4   z  faces the imprint material  3   z  on the substrate so that a side of the imprint mold  4   z  on which the depression-protrusion pattern is formed faces the imprint material  3   z . As illustrated in  FIG.  7 C , the substrate  1   z  on which the imprint material  3   z  is applied is brought into contact with the mold  4   z , and pressure is applied to the contacted substrate  1   z  and mold  4   z . A space between the mold  4   z  and the material to be processed  2   z  is filled with the imprint material  3   z . In this state, the imprint material  3   z  is cured if the imprint material  3   z  is irradiated with light as curing energy through the mold  4   z.    
     As illustrated in  FIG.  7 D , after the imprint material  3   z  is cured, the mold  4   z  is released from the substrate  1   z , and a pattern of a cured product of the imprint material  3   z  is formed on the substrate  1   z . The pattern of the cured product has a shape in which a depressed portion of the mold  4   z  corresponds to a protruded portion of the cured product, and a protruded portion of the mold  4   z  corresponds to a depressed portion of the cured product. In other words, the depression-protrusion pattern of the mold  4   z  is transferred onto the imprint material  3   z.    
     As illustrated in  FIG.  7 E , if etching is performed using the pattern of the cured product serving as an anti-etching mask, a portion of the surface of the material to be processed  2   z  where there is no cured product or a cured product remains thin is removed to form a groove  5   z . As illustrated in  FIG.  7 F , when the pattern of the cured product is removed, a product in which the groove  5   z  is formed on the surface of the material to be processed  2   z  can be obtained. While the pattern of the cured product is removed here, the pattern may not be removed after processing and may be employed as, for example, a film for interlayer insulation included in a semiconductor device or the like, i.e., a constituent member of the product. 
     While the exemplary embodiments of the present invention are described above, the present invention is not limited to the exemplary embodiments, and various modifications and changes are possible within the range of the gist of the present invention. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2019-059214, filed Mar. 26, 2019, which is hereby incorporated by reference herein in its entirety.