JP2013200496A - Transfer method and transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an alignment mark transferred with a transfer target object onto a substrate from becoming an obstacle in a later alignment process.SOLUTION: A first alignment mark AM1 formed on a substrate side in advance has a plurality of graphic patterns AP11-AP14 arranged separately from each other, and an alignment mark transfer area TR is surrounded by the graphic patterns AP11-AP14. A second alignment mark AM21 made of a pattern formation material on a blanket carrying a pattern is imaged together with the first alignment mark AM1, and according to a position detection result thereof, the substrate and the blanket are aligned. At this point, the second alignment mark is positioned in the alignment mark transfer area TR and transferred onto the substrate while being positioned at a location separate from the graphic patterns AP11-AP14 and the transferred second alignment mark.

Description

  The present invention relates to a transfer method and transfer apparatus for transferring a pattern or thin film supported on a surface of a carrier to a substrate, and in particular, the position of the substrate and the carrier based on the imaging result of an alignment mark carried on the carrier. This is related to the technique of matching.

  As a technique for forming a pattern or a thin film on the surface of a substrate, for example, a pattern or a thin film as a transfer object is temporarily supported on the surface of a flat carrier (for example, a glass plate), and this is adhered to the surface of the substrate to be covered. Some transfer the transferred material to the substrate surface. In such a transfer technique, an alignment process for aligning the relative position between the carrier and the substrate is necessary in order to appropriately transfer the transfer object to a predetermined position on the substrate surface.

  As an alignment technique that can be used for such an application, for example, there is one disclosed in Patent Document 1. In this technique, alignment marks are formed on the surfaces of two substrates to be bonded together, and alignment processing is performed based on images captured by an imaging means (for example, a CCD camera). Specifically, the alignment marks are imaged through the transparent one substrate in a state where both substrates are arranged so that the alignment mark forming surfaces face each other. And the relative position between board | substrates is adjusted based on the positional relationship of both the alignment marks detected from the imaged image. This technology relates to alignment processing when two substrates are bonded together. On the other hand, by replacing the substrate with a carrier, the carrier carrying the material to be transferred is superposed on a predetermined position of the substrate. The present invention can also be suitably applied to alignment at the time of transferring.

JP 2004-151653 A (for example, FIG. 1)

  In such a transfer technique, in order to adjust the positional relationship between the substrate and the transferred object transferred thereto with high accuracy, the same material as the transferred object is formed when the transferred object is formed on the carrier. May form an alignment mark. By forming the transferred object and the alignment mark at the same time, the positional relationship between the transferred object and the alignment mark is fixed on the carrier, and by adjusting the position of the alignment mark between the carrier and the substrate side, This is because it is possible to perform alignment with the transfer object.

  On the other hand, in this case, the alignment mark formed on the carrier is transferred to the substrate together with the transfer object. Therefore, for example, when transferring a plurality of layers to be transferred to the substrate, the alignment mark transferred to the substrate in the previous transfer may become an obstacle to the alignment process for the subsequent transfer. However, such problems and techniques for solving them have not been proposed so far.

  The present invention has been made in view of the above problems, and in the technology for transferring a transfer object carried on a carrier to a substrate, the alignment mark transferred to the substrate together with the transfer object is an obstacle to subsequent alignment processing. It aims at providing the technique which can prevent becoming.

  One aspect of the present invention is a transfer method for transferring a pattern or a thin film as a transfer object from a carrier carrying the transfer object to a predetermined position on a substrate. The substrate on which the alignment mark is formed on the surface, and the transferred object and the light-transmitting carrier that supports the transferred object and the second alignment mark formed on the surface using the same material as the transferred object. A holding step of holding the alignment mark forming surfaces close to each other in a state of facing each other, and the first alignment mark and the second through the carrier from the opposite side of the carrier to the alignment mark forming surface. Based on the imaging step of imaging the alignment mark within the same field of view of the imaging means, and the captured image, the first alignment mark and the second alignment mark A position detecting step for detecting the position of the mark, an alignment step for adjusting the relative position between the substrate and the carrier based on the detection result in the position detecting step, and the relative position adjusted in the alignment step. A transfer step of bringing the substrate and the carrier into contact with each other and transferring the transferred object and the second alignment mark on the surface of the carrier to the substrate; and the first alignment mark formed on the substrate includes: Including a plurality of graphic patterns spaced apart from each other, and the plurality of graphic patterns are arranged so as to surround an alignment mark transfer region where the second alignment mark can be arranged separately from each of the graphic patterns; In the alignment step, the relative position between the substrate and the carrier is adjusted to transfer the alignment mark. The second alignment mark is positioned opposite to an area of the area where the second alignment mark has not been transferred. In the transfer step, the second alignment mark is separated from each of the plurality of graphic patterns in the alignment mark transfer area. An alignment mark is transferred to the substrate.

  In the invention configured as described above, the second alignment mark transferred from the carrier to the substrate surface along with the transfer object by the alignment step is the alignment mark transfer region surrounded by the graphic pattern of the first alignment mark. The second alignment mark is positioned opposite to the area where the second alignment mark is not transferred. Therefore, in the image picked up by the image pickup means at this time, the image of the second alignment mark on the surface of the carrier is the image of the graphic pattern constituting the first alignment mark on the surface of the substrate and the second alignment that has already been transferred to the surface of the substrate. It does not overlap any of the mark images. That is, these images are isolated from each other.

  Therefore, in the position detection of the first alignment mark on the substrate surface and the second alignment mark on the surface of the carrier in the captured image, occurrence of detection errors due to interference of other images is suppressed. In addition, the second alignment mark carried on the surface of the carrier is transferred to the alignment mark transfer region on the substrate surface while being separated from each graphic pattern of the first alignment mark. Therefore, even on the substrate surface after the transfer, each graphic pattern of the first alignment mark is maintained in a state separated from the transferred second alignment mark. Therefore, also in the next alignment process, it is possible to accurately perform alignment with a new carrier using the graphic pattern of the first alignment mark.

  Thus, according to the present invention, the alignment mark transferred to the substrate together with the transfer object is prevented from becoming an obstacle to the subsequent alignment process, and even when transferring the transfer object to the substrate multiple times, In each case, the substrate and the carrier can be accurately aligned based on the imaging results of the first and second alignment marks.

  Note that if the second alignment mark transferred to the substrate only needs to be kept separated from the first alignment mark, the alignment mark transfer region may be set at a position separated from the first alignment mark. The area surrounded by the graphic pattern constituting the mark is not necessarily the alignment mark transfer area. However, by arranging each graphic pattern of the first alignment mark so as to surround the alignment mark transfer region as in the present invention, the first alignment mark and the second alignment mark before transfer are surely placed in the same field of view. Since they can be accommodated, the positional relationship between them can be easily grasped. This is because the second alignment mark before transfer automatically fits in the field of view by imaging the entire first alignment mark composed of a plurality of graphic patterns in the field of view.

  In addition, the alignment mark transfer region surrounded by a plurality of graphic patterns is more preferably a blank region in which no pattern is provided because the image affects the alignment process if any pattern exists.

  In this invention, for example, a transfer process from the carrier to the substrate is performed a plurality of times by performing a series of processes that sequentially execute the holding process, the imaging process, the position detection process, the alignment process, and the transfer process. In this case, the first alignment mark has an alignment mark transfer region in which a plurality of second alignment marks corresponding to a plurality of times of transfer can be arranged separately from each other. The second alignment marks may be transferred while being separated from each other.

  As described above, even when a series of processes is repeated a plurality of times, it is avoided that the second alignment mark previously transferred to the substrate becomes an obstacle to the subsequent alignment process. In order to transfer the second alignment marks while being separated from each other in each transfer process, the second alignment marks on the carrier are placed so as not to overlap the second alignment marks transferred to the substrate in each alignment process. Since the positioning is performed, the transferred second alignment mark does not deteriorate the alignment accuracy.

  In these inventions, for example, the graphic pattern of the first alignment mark includes more spatial frequency components lower than the graphic pattern of the second alignment mark. In the imaging step, the second pattern carried by the carrier is used. The alignment mark may be focused and imaged, and the position of the center of gravity of the graphic pattern of each of the first alignment mark and the second alignment mark may be detected in the position detection step.

  In the imaging process performed in the state where the substrate and the carrier are held close to each other, the positions of the first alignment mark and the second alignment in the optical axis direction of the imaging means are different, and thus it is not always possible to focus on both simultaneously. Absent. Therefore, in the present invention, while imaging is performed by focusing on the second alignment mark carried on the carrier, as a result of the first alignment mark that may not be focused, many low spatial frequency components are used. Include graphic pattern. Further, the barycentric positions of the first alignment mark and the second alignment mark are detected. Even if a high spatial frequency component is lost due to the lack of focus, if many low spatial frequency components remain, it is possible to detect the position of the center of gravity without a large error. Therefore, alignment with high accuracy is possible without necessarily focusing both alignment marks.

  In this case, for example, the graphic pattern of the first alignment mark may be a solid graphic and the graphic pattern of the second alignment mark may be a hollow graphic. Since the solid figure includes many low spatial frequency components, it is a figure suitable as the first alignment in which high-frequency components are easily lost because the focus is not achieved. On the other hand, the hollow figure contains many higher spatial frequency components and can be easily detected from the focused image by edge extraction or the like, and is therefore a figure suitable as the second alignment mark.

  Another aspect of the present invention is a transfer apparatus for transferring a pattern or a thin film as a transfer object from a carrier carrying the transfer object to a predetermined position on a substrate, in order to achieve the above object, The substrate having the first alignment mark formed on the surface, and the light-transmitting carrier that supports the transferred object and the second alignment mark formed on the surface with the transferred object using the same material as the transferred object. Are held close to each other with the alignment mark forming surfaces facing each other, and the carrier and the substrate are brought into contact with each other to transfer the transferred object and the second alignment mark from the carrier to the substrate. A transfer means for transferring to the substrate, and the substrate and the carrier are held in proximity by the transfer means, from the side opposite to the alignment mark forming surface of the carrier. Imaging means for imaging the first alignment mark and the second alignment mark in the same field of view of the imaging means via the carrier, and position detection of the first alignment mark and the second alignment mark in the captured image Alignment means for adjusting a relative position between the substrate and the carrier based on the result, and the alignment means adjusts a relative position between the substrate and the carrier, so that the first of the substrate surfaces is the first. The second alignment mark is opposed to an area where the second alignment mark is not transferred among the alignment mark transfer area surrounded by a plurality of graphic patterns constituting the alignment mark, and the transfer means is arranged in the alignment mark transfer area. The second aligner is separated from each of the plurality of graphic patterns by The at sign is characterized by transferring the substrate.

  Here, for example, when the transfer unit is configured to hold the substrate onto which the transferred object and the second alignment mark are transferred and transfer the new transferred object and the second alignment mark from the carrier to the substrate. The alignment means adjusts the relative position between the substrate and the carrier, and positions the new second alignment mark so as to face the region where the second alignment mark is not transferred in the alignment mark transfer region, The transfer unit may transfer the second alignment mark carried on the carrier to the substrate while being separated from each of the plurality of graphic patterns and the transferred second alignment mark in the alignment mark transfer region.

  In the invention configured as described above, as in the invention of the transfer method described above, the alignment mark transfer region surrounded by the plurality of graphic patterns constituting the first alignment mark is spaced apart from the plurality of graphic patterns. 2 Alignment marks are positioned and transferred to the substrate. When there is a second alignment mark that has been transferred in the alignment mark transfer region, the second alignment mark is positioned so as not to overlap with the second alignment mark. Therefore, similarly to the above-described transfer method invention, the first alignment mark formed on the substrate and the second alignment mark transferred onto the substrate are prevented from affecting the operation of the subsequent alignment means, and the first and It is possible to accurately align the substrate and the carrier based on the imaging result of the second alignment mark.

  In addition, for example, the imaging unit focuses on the second alignment mark carried on the carrier to perform imaging, and the alignment unit is based on the detection result of the center of gravity position of the graphic pattern of each of the first alignment mark and the second alignment mark. The relative position between the substrate and the carrier may be adjusted. Since the center of gravity of the figure can be detected sufficiently even from low spatial frequency components, even if the high spatial frequency component is lost due to incompatibility, the effect on the alignment accuracy between the substrate and the carrier is affected. It can be kept small.

  According to the present invention, the second alignment mark is separated from the plurality of graphic patterns constituting the first alignment mark on the surface of the substrate, and the second alignment mark is not transferred to the region of the alignment mark transfer region surrounded by the second alignment mark. Since the relative position between the substrate and the carrier is adjusted so as to position the mark, the alignment marks can be prevented from interfering with each other in the captured image, and the substrate and the carrier can be accurately positioned. . The effect is the same even when the object to be transferred is transferred to the substrate a plurality of times.

It is a perspective view which shows the printing apparatus equipped with the pattern formation apparatus concerning this invention. It is a figure which shows typically the cross section of the printing apparatus shown in FIG. It is a block diagram which shows the electric constitution of the apparatus of FIG. 2 is a flowchart illustrating an overall operation of the printing apparatus in FIG. 1. It is a figure which shows the detailed structure of an alignment stage. It is a figure which shows the detailed structure of an imaging part. It is a figure which shows the example of the pattern of an alignment mark. It is a figure which shows arrangement | positioning of the alignment mark for precision alignment operation | movement. It is a figure which shows an example of the image imaged with the CCD camera. It is a flowchart which shows the flow of a process of precision alignment operation | movement. It is a flowchart which shows a focusing operation | movement. It is a figure which shows the example of the image data by which contrast enhancement was carried out. It is a figure for demonstrating arrangement | positioning of an alignment mark.

  FIG. 1 is a schematic perspective view showing a printing apparatus equipped with a transfer apparatus according to the present invention, in which the apparatus cover is removed in order to clearly show the internal configuration of the apparatus. FIG. 2 is a diagram schematically showing a cross section of the printing apparatus shown in FIG. FIG. 3 is a block diagram showing an electrical configuration of the apparatus shown in FIG. The printing apparatus 100 is peeled after the upper surface of the blanket carried into the apparatus from the front side of the apparatus is brought into close contact with the lower surface of the plate PP carried into the apparatus from the left side of the apparatus. The pattern layer is formed by patterning the coating layer on the blanket with the pattern formed on the lower surface of the plate PP (patterning process). Further, the printing apparatus 100 is formed on the blanket by peeling off the upper surface of the patterned blanket after the upper surface of the substrate SB carried into the apparatus is brought into close contact with the lower surface of the substrate SB from the right side of the apparatus. The transferred pattern layer is transferred to the lower surface of the substrate SB (transfer process). In FIG. 1 and each drawing to be described later, in order to clarify the arrangement relationship of each part of the apparatus, the transport direction of the plate PP and the substrate SB is “X direction”, and the right hand side in FIG. The horizontal direction is referred to as “+ X direction”, and the reverse direction is referred to as “−X direction”. Further, among the horizontal directions orthogonal to the X direction, the front side of the apparatus is referred to as “+ Y direction” and the back side of the apparatus is referred to as “−Y direction”. Further, the upward direction and the downward direction in the vertical direction are referred to as “+ Z direction” and “−Z direction”, respectively.

  In this printing apparatus 100, each part of the apparatus (conveyance unit 2, upper stage unit 3, alignment unit 4, lower stage unit 5, pressing unit 7, pre-alignment unit 8, static elimination unit 9) is provided on the stone surface plate 1. The control unit 6 controls each part of the apparatus.

  The transport unit 2 is a device that transports the plate PP and the substrate SB in the X direction, and is configured as follows. In this transport unit 2, two brackets (not shown) are erected from the right rear corner and the left corner of the upper surface of the stone surface plate 1, and a ball screw mechanism so as to connect the upper ends of both brackets to each other. 21 extends in the left-right direction, that is, in the X direction. In this ball screw mechanism 21, a ball screw (not shown) extends in the X direction, and a rotary shaft (not shown) of a shuttle horizontal drive motor M21 is connected to one end thereof. A ball screw bracket (not shown) is screwed to the center of the ball screw, and a shuttle holding plate 22 extending in the X direction is attached to the (+ Y) side surface of the ball screw bracket. It has been.

  A plate shuttle 23L is provided at the (+ X) side end of the shuttle holding plate 22 so as to be movable up and down in the vertical direction Z, while a substrate shuttle 23R is provided at the (−X) side end so as to be movable up and down in the vertical direction Z. It has been. Since these shuttles 23L and 23R have the same configuration except for the hand rotation mechanism, here, the configuration of the plate shuttle 23L will be described, and the substrate shuttle 23R will be given the same or corresponding reference numerals. Therefore, description of the configuration is omitted.

  The shuttle 23L has an elevating plate 231 extending in the X direction approximately the same as or slightly longer than the width of the plate PP (X direction size), and the (+ X) side end and the (−X) side end of the elevating plate 231. It has two plate-use hands 232 and 232 extending to the front side, that is, the (+ Y) side. The elevating plate 231 is attached to the (+ X) side end of the shuttle holding plate 22 via a ball screw mechanism (not shown) so as to be elevable. In other words, the ball screw mechanism extends in the vertical direction Z with respect to the (+ X) side end of the shuttle holding plate 22. At the lower end of this ball screw mechanism, a rotary shaft (not shown) is connected to a plate shuttle lifting motor M22L (FIG. 3). A ball screw bracket (not shown) is screwed to the ball screw mechanism, and an elevating plate 231 is attached to the (+ Y) side surface of the ball screw bracket. For this reason, the plate lifting / lowering motor M22L is operated in accordance with an operation command from the motor control unit 63 of the control unit 6 so that the elevating plate 231 is driven up and down in the vertical direction Z.

  The front-rear size (Y-direction size) of each hand 232, 232 is longer than the length size (Y-direction size) of the plate PP, and the plate PP can be held on the front end side (+ Y side) of each hand 232, 232. Yes.

  In order to detect that the plate PP is held by the plate hands 232 and 232 in this way, a plate detection sensor (not shown) is provided from the center of the elevating plate 231 to the (+ Y) side via a sensor bracket. It is attached. For this reason, when the plate PP is placed on both hands 232, the sensor detects the rear end of the plate PP, that is, the (−Y) side end, and outputs a detection signal to the control unit 6.

  Further, the plate hands 232 and 232 are attached to the elevating plate 231 via bearings, and are rotatable about a rotation axis extending in the front-rear direction (Y direction). Further, rotary actuators RA2 and RA2 (FIG. 3) are attached to both ends of the elevating plate 231 in the X direction. These rotary actuators RA2 and RA2 operate using pressurized air as a drive source, and can be rotated in 180 ° units by opening and closing a valve inserted in a pressurized air supply path. For this reason, by controlling the opening and closing of the valve by the valve control unit 64 of the control unit 6, a hand posture suitable for handling the plate PP before patterning with one main surface of the plate hands 232 and 232 facing upward. (Hereinafter referred to as “unused posture”) and a hand posture suitable for handling the patterned PP with the other main surface facing upward (hereinafter referred to as “used posture”). It is possible. The point of having the hand posture switching mechanism is the only difference between the plate shuttle 23L and the substrate shuttle 23R.

  Next, attachment positions of the plate shuttle 23L and the substrate shuttle 23R with respect to the shuttle holding plate 22 will be described. In this embodiment, as shown in FIG. 2, the plate shuttle 23L and the substrate shuttle 23R have a width size of the plate PP or the substrate SB (in the embodiment, the width size of the plate PP and the substrate SB is the same). It is attached to the shuttle holding plate 22 spaced apart in the X direction by a longer interval. When the rotary shaft of the shuttle horizontal drive motor M21 is rotated in a predetermined direction, both the shuttles 23L and 23R move in the X direction while maintaining the above-mentioned separation distance. For example, in FIG. 2, the symbol XP23 indicates the position immediately below the upper stage unit 3, and the shuttles 23L and 23R are equidistant from the position XP23 in the (+ X) direction and the (−X) direction, respectively (this distance is “step movement”). It is located at positions XP22 and XP24 separated by "unit". In the present embodiment, the state shown in FIG. 2 is referred to as an “intermediate position state”.

  Further, when the rotary shaft of the shuttle horizontal drive motor M21 is rotated in a predetermined direction from this intermediate position state and the shuttle holding plate 22 is moved in the (+ X) direction by the step movement unit, the substrate shuttle 23R is moved in the (+ X) direction. It moves and moves to a position XP23 directly below the upper stage portion 3 for positioning. At this time, the plate shuttle 23L also moves integrally in the (+ X) direction and is positioned at a position XP21 close to a plate cleaning device (not shown) arranged on the (+ X) direction side of the printing apparatus 100.

  Conversely, when the rotary shaft of the shuttle horizontal drive motor M21 is rotated in the direction opposite to the predetermined direction and the shuttle holding plate 22 is moved in the (−X) direction by the step movement unit, the plate shuttle 23L is moved from the intermediate position state. It moves in the (−X) direction and moves to a position XP23 directly below the upper stage portion 3 to be positioned. At this time, the substrate shuttle 23R also moves integrally in the (−X) direction, and is positioned at a position XP25 close to the substrate cleaning device (not shown) arranged on the (−X) direction side of the printing apparatus 100. . Thus, in this specification, the five positions XP21 to XP25 are defined as the shuttle positions in the X direction. That is, the plate delivery position XP21 is the closest position to the plate cleaning device among the three positions XP21 to XP23 where the plate shuttle 23L is positioned, and the plate PP is carried into and out of the plate cleaning device X It means the direction position. The substrate delivery position XP25 is the closest position to the substrate cleaning apparatus among the three positions XP23 to XP25 where the substrate shuttle 23R is positioned, and the position in the X direction where the substrate SB is carried into and out of the substrate cleaning apparatus. Means. The position XP23 means an X-direction position where the suction plate 34 of the upper stage unit 3 moves in the vertical direction Z and sucks and holds the plate PP and the substrate SB, and the plate shuttle 23L is located at the X-direction position XP23. In this case, the position XP23 is referred to as a “plate suction position XP23”. On the other hand, when the substrate shuttle 23R is located at the X-direction position XP23, the position XP23 is referred to as a “substrate suction position XP23”. Called. In addition, the position in the vertical direction Z where the plate PP and the substrate SB are transported by the shuttles 23L and 23R, that is, the height position is referred to as a “transport position”.

  In the present embodiment, the thickness of the plate PP and the substrate SB is measured in order to accurately control the gap amount between the plate PP and the blanket during patterning and the gap amount between the substrate SB and the blanket during transfer. There is a need. Therefore, a plate thickness measurement sensor SN22 and a substrate thickness measurement sensor SN23 are provided. In the present embodiment, a reflection type optical sensor having a light projecting part and a light receiving part is used as both sensors SN22 and SN23, but other sensors may be used.

  At the position XP23, the upper stage unit 3 is arranged. In the upper stage portion 3, a ball screw mechanism 31 extending in the vertical direction Z is fixed, and a rotating shaft (not shown) of the first stage lifting motor M 31 is attached to the upper end portion of the ball screw mechanism 31. In addition to being connected, a ball screw bracket (not shown) is screwed into the ball screw mechanism 31. A support frame 32 is fixed to the ball screw bracket, and can be moved up and down in the vertical direction Z integrally with the ball screw bracket. Further, another ball screw mechanism (not shown) is supported on the frame surface of the support frame 32. This ball screw mechanism is provided with a ball screw having a narrower pitch than the ball screw of the ball screw mechanism 31, and a rotary shaft (not shown) of the second stage lifting motor M32 (FIG. 3) is provided at the upper end thereof. While being connected, a ball screw bracket is screwed into the central portion.

  A stage holder 33 is attached to the ball screw bracket. A metal suction plate 34 such as an aluminum alloy is attached to the lower surface of the stage holder 33. Therefore, the suction plate 34 is moved up and down in the vertical direction Z by operating the stage lifting motors M31 and M32 in accordance with an operation command from the motor control unit 63 of the control unit 6. Further, in the present embodiment, by combining ball screw mechanisms having different pitches and operating the first stage elevating motor M31, the suction plate 34 can be moved up and down at a relatively wide pitch, that is, the suction plate 34 can be moved at high speed. In addition, the suction plate 34 can be moved up and down at a relatively narrow pitch by operating the second stage lifting motor M32, that is, the suction plate 34 can be precisely positioned.

  A suction mechanism is provided on the lower surface of the suction plate 34, that is, a suction surface for sucking and holding the plate PP and the substrate SB, and is connected to a negative pressure supply source via a negative pressure supply path. The suction valve V31 (FIG. 3) connected to the suction mechanism is controlled to open / close in accordance with an opening / closing command from the valve control unit 64 of the control unit 6, so that the plate PP and the substrate SB can be sucked by the suction mechanism. In the present embodiment, the above-described suction mechanism and the suction mechanism that sucks and holds the blanket as described later use factory power as a negative pressure supply source, but the apparatus 100 is a negative pressure supply unit such as a vacuum pump. The negative pressure supply unit may be configured to supply negative pressure to the suction mechanism.

  In the upper stage unit 3 configured as described above, after the plate is transported from the left hand side of FIG. 1 to the plate suction position XP23 directly below the upper stage unit 3 through the transport space by the plate shuttle 23L of the transport unit 2. Then, the suction plate 34 of the upper stage unit 3 descends to hold the plate PP by suction. Conversely, when the suction plate 34 that has attracted the plate PP is released while the plate shuttle 23L is positioned immediately below the upper stage unit 3, the plate PP is transferred to the transport unit 2. In this way, the plate is delivered between the transport unit 2 and the upper stage unit 3.

  Further, the substrate SB is also held by the upper stage unit 3 in the same manner as the plate PP. That is, after the substrate SB is transported from the right hand side of FIG. 1 to the position immediately below the upper stage unit 3 by the substrate shuttle 23R of the transport unit 2, the suction plate 34 of the upper stage unit 3 is lowered. The substrate SB is sucked and held. Conversely, when the suction plate 34 of the upper stage unit 3 that has sucked the substrate SB is released while the substrate shuttle 23 </ b> R is positioned immediately below the upper stage unit 3, the substrate SB is transferred to the transport unit 2. . In this way, the substrate SB is delivered between the transport unit 2 and the upper stage unit 3.

  Below the upper stage portion 3 in the vertical direction (hereinafter referred to as “vertically below” or “(−Z) direction”), the alignment portion 4 is disposed on the upper surface of the stone surface plate 1. In the alignment unit 4, the support plate 41 is disposed in a horizontal posture so as to straddle the concave portion of the stone surface plate 1 and is fixed to the upper surface of the stone surface plate 1 as shown in FIG. 1. An alignment stage 42 is fixed on the upper surface of the support plate 41. The lower stage unit 5 is placed on the alignment stage 42 of the alignment unit 4, and the upper surface of the lower stage unit 5 faces the suction plate 34 of the upper stage unit 3. The upper surface of the lower stage unit 5 can suck and hold the blanket BL, and the control unit 6 controls the alignment stage 42 so that the blanket BL on the lower stage unit 5 can be positioned with high accuracy.

  The alignment stage 42 includes a stage base 421 that is fixed on the support plate 41, and a stage top 422 that is disposed vertically above the stage base 421 and supports the lower stage unit 5. Both the stage base 421 and the stage top 422 have a frame shape having an opening in the center. Between the stage base 421 and the stage top 422, a support mechanism such as a cross roller bearing having three degrees of freedom in the rotational direction, the X direction, and the Y direction with the rotational axis extending in the vertical direction Z as the rotational center. 423 is arranged in the vicinity of each corner of the stage top 422. Each support mechanism 423 is provided with a ball screw mechanism (not shown), and a stage drive motor M41 (FIG. 3) is attached to each ball screw mechanism. Then, by operating each stage drive motor M41 in accordance with an operation command from the motor control unit 63 of the control unit 6, the stage top 422 is placed in a horizontal plane while providing a relatively large space at the center of the alignment stage 42. The suction plate 51 of the lower stage unit 5 can be positioned by being moved and rotated about the vertical axis. In this embodiment, one of the reasons for using the alignment stage 42 having a hollow space is formed on the blanket BL held on the upper surface of the lower stage portion 5 and the substrate SB held on the lower surface of the upper stage portion 3. This is because the alignment mark is imaged by the imaging unit 43.

  The lower stage unit 5 includes a suction plate 51, a column member 52, a stage base 53, and a lift pin unit 54. The stage base 53 is provided with three elongated holes extending in the left-right direction X and arranged in the front-rear direction Y. The stage base 53 is fixed on the alignment stage 42 so that these long hole openings and the central opening of the alignment stage 42 overlap in a plan view from above. In addition, a part of the imaging unit 43 is loosely inserted into the long hole opening. A column member 52 is erected at (+ Z) from the upper surface corner of the stage base 53, and each apex supports the suction plate 51.

  The suction plate 51 is made of a metal plate such as an aluminum alloy. A suction mechanism (not shown) is provided on the upper surface of the suction plate 51, one end of a positive pressure supply pipe (not shown) is connected to the suction mechanism, and the other end is connected to a pressurizing manifold. ing. Further, a pressurizing valve V51 (FIG. 3) is inserted in an intermediate portion of each positive pressure supply pipe. The pressure manifold is constantly supplied with a constant pressure of air obtained by adjusting the pressure of air supplied from the factory power with a regulator. For this reason, when a desired pressurization valve V51 is selectively opened in accordance with an operation command from the valve control unit 64 of the control unit 6, the pressure is adjusted with respect to the adsorption mechanism connected to the selected pressurization valve V51. Pressurized air is supplied.

  Moreover, not only selective supply of pressurized air but also selective negative pressure supply is possible for a part of the adsorption mechanism. That is, one end of a negative pressure supply pipe (not shown) is connected to each of the specific adsorption mechanisms, and the other end is connected to a negative pressure manifold. Further, an adsorption valve V52 (FIG. 3) is inserted in an intermediate portion of each negative pressure supply pipe. A negative pressure supply source is connected to the negative pressure manifold via a regulator, and a predetermined negative pressure is constantly supplied. For this reason, when a desired suction valve V52 is selectively opened in accordance with an operation command from the valve control unit 64 of the control unit 6, the negative pressure adjusted with respect to the suction mechanism connected to the selected suction valve V52. Is supplied.

  As described above, in this embodiment, the blanket BL is partially or completely adsorbed on the suction plate 51 by opening / closing control of the valves V51 and V52, or air is partially supplied between the suction plate 51 and the blanket BL. Then, the blanket BL is partially inflated and can be pressed against the plate PP and the substrate SB held on the upper stage portion 3.

  In the lift pin portion 54, a lift plate 541 is provided between the suction plate 51 and the stage base 53 so as to be movable up and down. The lift plate 541 is formed with notches at a plurality of locations to prevent interference with the imaging unit 43. In addition, a plurality of lift pins 542 are erected vertically upward from the upper surface of the lift plate 541. On the other hand, a pin elevating cylinder CL51 (FIG. 3) is connected to the lower surface of the lift plate 541. And the valve | bulb control part 64 of the control part 6 switches the opening / closing of the valve connected to the pin raising / lowering cylinder CL51, thereby operating the pin raising / lowering cylinder CL51 to raise / lower the lift plate 541. As a result, all the lift pins 542 are moved back and forth with respect to the upper surface of the suction plate 51, that is, the suction surface. For example, the lift pins 542 project from the upper surface of the suction plate 51 in the (+ Z) direction, so that the blanket BL can be placed on the top of the lift pins 542 by a blanket transport robot (not shown). Then, following the placement of the blanket BL, the lift pin 542 moves backward in the (−Z) direction from the upper surface of the suction plate 51, so that the blanket BL is transferred to the upper surface of the suction plate 51. Thereafter, the thickness of the blanket BL is measured by a blanket thickness measurement sensor SN51 (FIG. 3) disposed in the vicinity of the suction plate 51 at an appropriate timing as will be described later.

  As described above, in the present embodiment, the upper stage unit 3 and the lower stage unit 5 are disposed to face each other in the vertical direction Z. Between them, a pressing unit 7 that presses the blanket BL placed on the lower stage unit 5 from above and a pre-alignment unit 8 that pre-aligns the plate PP, the substrate SB, and the blanket BL are arranged. ing.

  The pressing part 7 can be switched between two states by raising and lowering a pressing member 71 provided vertically above the suction plate 51 in the vertical direction Z by a switching mechanism (not shown). That is, when the switching mechanism lowers the pressing member 71, the blanket BL on the suction plate 51 is pressed by the pressing portion 7 (a blanket pressing state). On the other hand, when the switching mechanism raises the pressing member 71, the pressing portion 7 is separated from the blanket BL and is released from the blanket BL (a blanket pressing release state).

  In the pre-alignment unit 8, the pre-alignment upper part 81 and the pre-alignment lower part 82 are stacked in two stages in the vertical direction Z. Among these, the pre-alignment upper portion 81 is arranged vertically above the pre-alignment lower portion 82, and is brought into contact with the blanket BL by the plate PP and the substrate shuttle 23R held by the plate shuttle 23L at the position XP23. The substrate SB to be held is aligned. On the other hand, the pre-alignment lower part 82 aligns the blanket BL placed on the suction plate 51 of the lower stage unit 5 prior to close contact with the plate PP and the substrate SB. Note that the pre-alignment upper portion 81 and the pre-alignment lower portion 82 basically have the same configuration. Therefore, in the following, the configuration of the pre-alignment upper portion 81 will be described, and the pre-alignment lower portion 82 will be assigned the same or corresponding reference numerals, and the description of the configuration will be omitted.

  In the pre-alignment upper portion 81, four upper guides 812 are movably provided with respect to the frame-like frame structure 811. That is, the frame structure 811 includes two horizontal frames spaced apart in the left-right direction X and extending in the front-rear direction Y, and two horizontal frames spaced apart in the front-rear direction Y and extended in the left-right direction X. Are combined. Then, as shown in FIG. 2, the upper guide 812 at the center of the left horizontal plate of the two horizontal plates extending in the front-rear direction Y is moved in the left-right direction X by a ball screw mechanism (not shown). It is provided to be freely movable. The upper guide 812 moves in the left-right direction X when the drive motor M81 (FIG. 3) coupled to the ball screw mechanism operates in accordance with an operation command from the motor control unit 63 of the control unit 6. Similarly to the above, the upper guide 812 is configured to move in the left-right direction X by the drive motor M81 with respect to the right horizontal plate. Further, for each of the two horizontal plates extending in the front-rear direction Y, the upper guide 812 is configured to move in the left-right direction X by the drive motor M81 as described above. In this way, the four upper guides 812 surround the plate PP and the substrate SB at a position vertically below the position XP23, and each upper guide 812 can be moved toward and away from the plate PP independently. Therefore, it is possible to align the plate PP and the substrate SB by horizontally moving or rotating them on the shuttle hand by controlling the movement amount of each upper guide 812.

  In this embodiment, as will be described later, after the pattern layer on the blanket BL is transferred to the substrate SB, the blanket BL is peeled off from the substrate SB, and static electricity is generated in the peeling step. In addition, static electricity is generated when the blanket BL is peeled from the plate PP after the coating layer on the blanket BL is patterned by the plate PP. Therefore, in the present embodiment, a static elimination unit 9 is provided to neutralize static electricity. The charge removal unit 9 includes an ionizer 91 that irradiates ions toward a space sandwiched between the upper stage unit 3 and the lower stage unit 5 from the (+ X) side.

  The control unit 6 includes a CPU (Central Processing Unit) 61, a memory 62, a motor control unit 63, a valve control unit 64, an image processing unit 65, and a display / operation unit 66. The CPU 61 is stored in the memory 62 in advance. Each part of the apparatus is controlled according to the program, and the patterning process and the transfer process are executed as shown in FIG.

  FIG. 4 is a flowchart showing the overall operation of the printing apparatus of FIG. In the initial state of the printing apparatus 100, the plate shuttle 23L and the substrate shuttle 23R are positioned at intermediate positions XP22 and XP24, respectively. The plate PP loading process (step S1) and the substrate SB of the substrate cleaning robot (not shown) of the substrate cleaning apparatus are transferred in synchronism with the plate PP transfer operation of the plate cleaning robot (not shown) of the plate cleaning apparatus. In synchronization with the operation, the substrate SB loading step (step S2) is executed. Since the plate shuttle 23L and the substrate shuttle 23R integrally move in the left-right direction X, the plate PP is loaded (step S1), and then the substrate SB is loaded. (Step S2) may interchange the order of both.

  As described above, in this embodiment, not only the plate PP but also the substrate SB is prepared before the patterning process is performed, and the patterning process and the transfer process are continuously performed as will be described in detail later. To do. As a result, the time interval until the coating layer patterned on the blanket BL is transferred to the substrate SB can be shortened, and stable processing is performed.

  In the next step S3, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (−X) direction. As a result, the plate shuttle 23L moves to the plate suction position XP23 and is positioned. Then, the plate shuttle elevating motor M22L rotates the rotation shaft to move the elevating plate 231 downward (-Z). As a result, the plate PP is moved and positioned to a pre-alignment position lower than the transport position while being supported by the plate shuttle 23L.

  Next, the upper guide drive motor M81 is actuated to move the upper guide 812, and each upper guide 812 contacts the end face of the plate PP supported by the plate shuttle 23L to position the plate PP at a preset horizontal position. To do. Thereafter, each upper guide drive motor M81 operates in the reverse direction, and each upper guide 812 is separated from the plate PP. Thus, when the pre-alignment processing of the plate PP is completed, the stage elevating motor M31 rotates the rotating shaft in a predetermined direction, and the suction plate 34 is lowered downward (−Z) to contact the upper surface of the plate PP. Subsequently, the valve V31 is opened, whereby the plate PP is sucked onto the suction plate 34 by the upper stage suction mechanism.

  When the adsorption of the plate PP is completed in this way, the stage elevating motor M31 rotates in the reverse direction, and the adsorption plate 34 moves up vertically while adsorbing and holding the plate PP, so that the plate PP is placed at a position above the plate adsorption position XP23. Move. Then, the plate shuttle elevating motor M22L rotates the rotation shaft to move the elevating plate 231 vertically upward, and the plate shuttle 23L is moved from the pre-alignment position to the transport position, that is, the plate suction position XP23 and positioned. Thereafter, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (+ X) direction, and the empty plate shuttle 23L is positioned at the intermediate position XP22.

  In the next step S4, the stage drive motor M41 is operated to move the alignment stage 42 to the initial position. As a result, the start becomes the same position every time. Subsequently, the pin elevating cylinder CL51 operates to raise the lift plate 541 and cause the lift pin 542 to protrude vertically upward from the upper surface of the suction plate 51. Thus, when the blanket BL preparation is completed, a blanket transport robot (not shown) accesses the apparatus 100 and places the blanket BL on the top of the lift pin 542 and then withdraws from the apparatus 100. Next, the pin lifting cylinder CL51 operates to lower the lift plate 541. As a result, the lift pins 542 descend while supporting the blanket BL and place the blanket BL on the suction plate 51. Then, the lower guide drive motor M82 operates, the lower guide 822 moves, and each lower guide 822 contacts the end face of the blanket BL supported by the suction plate 51 to position the blanket BL at a preset horizontal position.

  When the pre-alignment process of the blanket BL is completed in this way, the suction valve V52 is opened, whereby a negative pressure adjusted to the lower stage suction mechanism is supplied, and the blanket BL is sucked to the suction plate 51. Further, each lower guide drive motor M82 rotates the rotating shaft in the reverse direction, and each lower guide 822 is separated from the blanket BL. Thereby, the preparation for the patterning process is completed.

  In the next step S5, the sensor horizontal drive cylinder CL52 (FIG. 3) operates to position the blanket thickness measurement sensor SN51 at a position immediately above the right end of the blanket BL. And blanket thickness measurement sensor SN51 outputs the information relevant to the thickness of blanket BL to the control part 6, and, thereby, the thickness of blanket BL is measured. Thereafter, the sensor horizontal drive cylinder CL52 operates in the reverse direction to retract the blanket thickness measurement sensor SN51 from the suction plate 51.

  Next, the first stage elevating motor M31 rotates the rotating shaft in a predetermined direction, lowers the suction plate 34 downward (−Z), and moves the plate PP to the vicinity of the blanket BL. Further, the second stage elevating motor M32 rotates the rotating shaft to raise and lower the suction plate 34 at a narrow pitch, thereby accurately adjusting the interval between the plate PP and the blanket BL in the vertical direction Z, that is, the gap amount. The gap amount is determined by the control unit 6 based on the thickness measurement results of the plate PP and the blanket BL.

  Then, the pressing member 71 of the pressing part 7 is lowered and the peripheral edge of the blanket BL is pressed by the pressing member 71 over the entire circumference. Subsequently, the valves V51 and V52 operate to partially supply air between the suction plate 51 and the blanket BL to partially expand the blanket BL. This floating portion is pressed against the plate PP held on the upper stage portion 3. As a result, the central portion of the blanket BL is in close contact with the plate PP, and a pattern formed in advance on the lower surface of the plate PP comes into contact with the coating layer previously applied on the upper surface of the blanket BL, and the coating layer is patterned to form a pattern layer. Form.

  In the next step S6, the second stage elevating motor M32 rotates the rotating shaft, and the suction plate 34 is raised to peel the plate PP from the blanket BL. Further, in parallel with raising the plate PP to perform the peeling process, the valve V51, V52 is switched between open and closed, and negative pressure is applied to the blanket BL to draw it toward the suction plate 51. After that, the first stage elevating motor M31 rotates the rotation shaft to raise the suction plate 34 and position the plate PP at a static elimination position substantially the same height as the ionizer 91. Further, the pressing member 71 of the pressing unit 7 is raised to release the blanket BL. Subsequently, the ionizer 91 operates to remove static electricity generated during the plate peeling process. When this removal process is completed, the first stage elevating motor M31 rotates the rotation shaft, and the suction plate 34 moves up to the initial position (position higher than the plate suction position XP23) while sucking and holding the plate PP.

  In the next step S7, the rotary actuators RA2 and RA2 operate to rotate the plate hands 232 and 232 by 180 ° to position them from the origin position to the reverse position. As a result, the hand posture is switched from the unused posture to the used posture, and the preparation for receiving the used plate PP is completed. Then, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (−X) direction. As a result, the plate shuttle 23L moves to the plate suction position XP23 and is positioned.

  On the other hand, the first stage elevating motor M31 rotates the rotation shaft, the suction plate 34 descends toward the hands 232, 232 of the plate shuttle 23L while holding the plate PP, and the plate PP is placed on the hands 232, 232. After the positioning, the valves V31 and V32 are closed, whereby the suction of the plate PP by the suction mechanism of the suction plate 34 is released, and the delivery of the plate PP at the transport position is completed. Then, the first stage elevating motor M31 rotates the rotating shaft in the reverse direction to raise the suction plate 34 to the initial position. Thereafter, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (+ X) direction. As a result, the plate shuttle 23L moves to the intermediate position XP22 and is positioned while holding the used plate PP.

  In the next step S8, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (+ X) direction. Thus, the substrate shuttle 23R that holds the unprocessed substrate SB moves to the substrate suction position XP23 and is positioned. Then, the pre-alignment process of the substrate SB and the suction process of the substrate SB are performed in the same manner as the pre-alignment process of the plate PP and the suction process of the plate PP by the suction plate 34. Thereafter, when the adsorption of the substrate SB is detected, the stage elevating motor M31 rotates the rotation shaft, and the adsorption plate 34 is moved vertically upward while the substrate SB is adsorbed and held, so that the substrate SB is positioned higher than the substrate adsorption position XP23. Move. Then, the substrate shuttle elevating motor M22R rotates the rotation shaft to move the substrate shuttle 23R from the pre-alignment position to the transport position for positioning. Thereafter, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (−X) direction, and positions the empty substrate shuttle 23R at the intermediate position XP24.

  In the next step S9, the blanket thickness is measured, and after the fine alignment is executed, the transfer process is executed. That is, the thickness of the blanket BL is measured in the same manner as the thickness measurement in the patterning process. The main reason for measuring the thickness of the blanket BL not only immediately before patterning but also immediately before transfer is that the thickness of the blanket BL changes with time due to swelling of a part of the blanket BL. By measuring the blanket thickness at, a highly accurate transfer process can be performed.

  Next, the first stage elevating motor M31 rotates the rotation shaft in a predetermined direction, lowers the suction plate 34 downward (−Z), and moves the substrate SB to the vicinity of the blanket BL. Further, the second stage elevating motor M32 rotates the rotating shaft to raise and lower the suction plate 34 at a narrow pitch, thereby accurately adjusting the distance between the substrate SB and the blanket BL in the vertical direction Z, that is, the gap amount. The gap amount is determined by the control unit 6 based on the thickness measurement results of the substrate SB and the blanket BL. Then, similarly to the patterning (step S5), the pressing member 71 presses the peripheral edge of the blanket BL.

  Thus, both the substrate SB and the blanket BL are pre-aligned and positioned at a distance suitable for the transfer process, but in order to accurately transfer the pattern layer formed on the blanket BL to the substrate SB. It is necessary to align the two precisely. Therefore, in the present embodiment, the imaging unit 43 images the alignment marks patterned on the blanket BL and the alignment marks formed on the substrate SB, and outputs these images to the image processing unit 65 of the control unit 6. Based on these images, the control unit 6 obtains a control amount for aligning the blanket BL with respect to the substrate SB, and further creates an operation command for the stage drive motor M41 of the alignment unit 4. Then, the stage drive motor M41 operates according to the control command to move the suction plate 51 in the horizontal direction and rotate around the virtual rotation axis extending in the vertical direction Z to precisely align the blanket BL with the substrate SB. (Alignment process).

  Then, the valves V51 and V52 are operated to partially supply air between the suction plate 51 and the blanket BL to partially inflate the blanket BL. This floating portion is pressed against the substrate SB held on the upper stage portion 3. As a result, the blanket BL adheres to the substrate SB. Thus, the pattern layer on the blanket BL side is transferred to the substrate SB while being precisely aligned with the pattern on the lower surface of the substrate SB.

  In the next step S10, similarly to the plate peeling (step S6), the peeling of the substrate SB from the blanket BL, the positioning of the substrate SB to the discharging position, the pressing release of the blanket BL by the pressing member 71, and discharging are executed. Thereafter, the first stage elevating motor M31 rotates the rotation shaft, and the suction plate 34 moves up to the initial position (position higher than the transport position) while holding the substrate SB by suction.

  In the next step S11, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (+ X) direction. As a result, the substrate shuttle 23R moves to the substrate suction position XP23 and is positioned. Further, the first stage elevating motor M31 rotates the rotation shaft to lower the suction plate 34 toward the hands 232 and 232 of the substrate shuttle 23R while holding the substrate SB. Thereafter, the valve V31 is closed, whereby the adsorption of the substrate SB by the adsorption mechanism is released. Then, the first stage elevating motor M31 rotates the rotating shaft in the reverse direction to raise the suction plate 34 to the initial position. Thereafter, the shuttle horizontal drive motor M21 rotates the rotating shaft, moves the shuttle holding plate 22 in the (−X) direction, and moves the substrate shuttle 23R to the intermediate position XP24 while holding the substrate SB, thereby positioning.

  In the next step S12, the valves V51 and V52 are operated to release the suction of the blanket BL by the suction plate 51. Then, the pin lifting cylinder CL51 operates to raise the lift plate 541 and lift the used blanket BL vertically upward from the suction plate 51. Then, the blanket transport robot accesses the apparatus 100 to receive the used blanket BL from the top of the lift pin 542 and retracts from the apparatus 100. Following this, the pin elevating cylinder CL51 operates to lower the lift plate 541 and lower the lift pin 542 downward (−Z) from the suction plate 51.

  In the next step S13, the shuttle horizontal drive motor M21 rotates the rotation shaft, and the shuttle holding plate 22 moves in the (+ X) direction. As a result, the plate shuttle 23L moves to the plate delivery position XP21 and is positioned. Subsequently, the used plate PP is taken out from the printing apparatus 100 by the plate transport robot of the plate cleaning apparatus. When unloading of the plate PP is completed in this way, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (−X) direction, thereby positioning the plate shuttle 23L at the intermediate position XP22.

  In the next step S14, the shuttle horizontal drive motor M21 rotates the rotation shaft, and moves the shuttle holding plate 22 in the (−X) direction. Thus, the substrate shuttle 23R is moved to the substrate delivery position XP25 and positioned. Subsequently, the substrate transport robot of the substrate cleaning apparatus takes out the substrate SB subjected to the transfer process from the printing apparatus 100. When the unloading of the substrate SB is completed in this manner, the shuttle horizontal drive motor M21 rotates the rotation shaft to move the shuttle holding plate 22 in the (+ X) direction, thereby positioning the substrate shuttle 23R at the intermediate position XP23. Thereby, the printing apparatus 100 returns to the initial state.

  Next, the precise alignment operation in the printing apparatus 100 configured as described above will be described in more detail. As described above, in this embodiment, precise alignment between the blanket BL held on the upper surface of the lower stage portion 5 and the substrate SB held on the lower surface of the upper stage portion 3 is performed on the alignment formed in advance on these. The mark is picked up by the image pickup unit 43 and the alignment stage 42 is operated based on the image pickup result. Here, the assumed planar size of the substrate SB is about 350 mm × 300 mm. On the other hand, the alignment accuracy between the target substrate SB and the blanket BL is, for example, about ± 3 μm.

  FIG. 5 is a diagram showing a detailed structure of the alignment stage. As described above, the alignment stage 42 includes the stage base 421 and the stage top 422. The support mechanism 423 is provided between them, and the stage drive motor M41 drives the support mechanism 423, whereby the stage base. Movement of the stage top 422 relative to 421 is realized. In FIG. 5, the support mechanisms 423 provided at the four corners of the stage base 421 are distinguished from each other by reference numerals 423a, 423b, 423c, and 423d. Further, the stage drive motor M41 coupled to each of these is denoted by reference numerals M41a, M41b, M41c, and M41d, respectively.

  The stage drive motor M41a drives the support mechanism 423a, so that the support mechanism 423a can move in a predetermined range in the Y direction as indicated by a dotted arrow in the vicinity of the support mechanism 423a. Also, as indicated by dotted arrows in the vicinity of each of them, the stage drive motor M41b has the support mechanism 423b in the X direction, the stage drive motor M41c has the support mechanism 423c in the Y direction, and the stage drive motor M41d has the support mechanism 423d in the X direction. In addition, each can move within a predetermined range.

  As the support mechanisms 423 a and 423 c move in the same direction, the stage top 422 moves in the (+ Y) direction or the (−Y) direction with respect to the stage base 421. Further, the stage top 422 moves in the (+ X) direction or the (−X) direction with respect to the stage base 421 by the support mechanisms 423b and 423d moving in the same direction. On the other hand, the stage top 422 rotates around the vertical axis with respect to the stage base 421 as they move in opposite directions. In this manner, movement of the stage top 422 relative to the stage base 421 in the horizontal plane (XY plane) and rotational movement about the Z axis are realized.

  FIG. 6 is a diagram illustrating a detailed structure of the imaging unit. As shown in FIG. 2, the imaging unit 43 has an upper end extending directly below the suction plate 51 of the lower stage unit 5, and a CCD camera 430 shown in FIG. In addition, although the imaging part 43 is provided in four places corresponding to the four corners of the blanket BL sucked and held by the suction plate 51, the structures of these imaging parts 43 are the same.

  Transparent quartz windows 52a are fitted into the suction plate 51 at positions corresponding to the four corners of the blanket BL so that the blanket BL can be seen through the quartz window 52a from below the suction plate 51. A CCD camera 430 is disposed below the quartz window 52a. Specifically, the objective lens 435, the half mirror 437, and the light receiving surface 438 of the CCD image sensor are arranged in this order immediately below the quartz window 52a. The optical axis of the objective lens 435 coincides with the substantially vertical direction, and the quartz window 52a and the light receiving surface 438 are respectively disposed on the optical axis. Light from the light source 436 is incident on the half mirror 437 from the side. The light is reflected by the half mirror 437 and emitted toward the quartz window 52a, and then enters the blanket BL via the quartz window 52a.

  A predetermined first alignment mark AM1 is formed in advance at a position facing the quartz window 52a on the lower surface of the substrate SB held on the lower surface of the suction plate 34 of the upper stage portion 3. On the other hand, a predetermined second alignment mark AM2 is formed in advance at a position facing the quartz window 52a on the upper surface of the blanket BL held on the upper surface of the suction plate 51 of the lower stage portion 5. That is, the substrate SB and the blanket BL are arranged to face each other so that the respective alignment mark formation surfaces face each other. Thereby, the distance between the alignment marks in the vertical direction (Z direction) can be reduced. The gap Gsb between the substrate SB and the blanket BL after the gap adjustment is desirably as small as possible. However, in consideration of the dimensional accuracy of each part of the apparatus, the deflection of the substrate SB and the blanket BL, etc., the substrate SB and the blanket In order to prevent unscheduled contact with the BL, it must be separated to some extent. Here, for example, the interval Gsb is set to 300 μm.

  The blanket BL is formed by forming a thin elastic layer of, for example, silicon rubber on the surface of a glass plate or a transparent resin plate, and has light transmittance. Therefore, the first alignment mark AM1 and the second alignment mark AM2 can be seen from below the lower stage portion 5 through the quartz window 52a and the blanket BL. The CCD light receiving surface 438 images the first alignment mark AM1 and the second alignment mark AM2 arranged facing the quartz window 52a at once in the same field of view.

  The objective lens 435, the half mirror 437, the light receiving surface 438, and the light source 436 are integrally movable in the direction along the XY plane by the XY table 431 and in the vertical direction (Z direction) by the precision lifting table 432. . The front focal point of the objective lens 435 is aligned with the alignment mark forming surface of the blanket BL by the precision lifting table 432. On the other hand, the rear focus is adjusted in advance to the light receiving surface 438 of the CCD image sensor. For this reason, an optical image in focus (within the focus) is formed on the CCD light receiving surface 438 on the second alignment mark AM2 formed on the blanket BL, and this optical image is picked up by the CCD camera 430.

  The second alignment mark AM2 is formed on the surface of the elastic layer of the blanket BL simultaneously with the pattern formation by using the same material as the pattern to be transferred to the substrate. That is, a pattern corresponding to the alignment mark AM2 is formed in advance on the plate PP together with a pattern to be transferred to the substrate SB. When patterning is performed by bringing the plate PP into close contact with the coating layer on the blanket BL, the alignment mark AM2 is formed. Are also formed at the same time. As described above, of the main surfaces of the blanket BL, one main surface on the side where the elastic layer is formed serves as a pattern and alignment mark forming surface.

  FIG. 7 is a diagram showing an example of an alignment mark pattern. More specifically, FIG. 7A shows a first alignment mark formed on the substrate in this embodiment, and FIG. 7B shows a second alignment mark formed on the blanket in this embodiment.

  As shown in FIG. 7A, the first alignment mark AM1 formed on the substrate SB is composed of a plurality of (four in this example) first alignment patterns AP1 (AP11 to AP14) spaced apart from each other. . Each alignment pattern AP1 is of a size that does not erase the figure even when it is out of focus, for example, a rectangle with one side of about 50 μm (in this example, a square), and the inside surrounded by the four sides is uniformly filled It is a real figure. Four such first alignment patterns AP1 are arranged at positions where the apexes of each square are formed to form the first alignment mark AM1. The interval between the alignment patterns AP1 is 750 μm.

  On the other hand, as shown in FIG. 7B, the second alignment mark AM2 formed on the blanket BL is composed of a single second alignment pattern AP2. The second alignment pattern AP2 is, for example, an annular hollow figure that is a rectangle having one side of about 120 μm and is hollowed out. The line width of each side forming a square is, for example, 10 μm, and therefore one side of the inner square is about 100 μm.

  FIG. 7C shows the spatial frequency spectrum of these alignment patterns. Comparing the spatial frequency components of these patterns, the first alignment pattern AP1 that is a solid figure includes more low frequency components than the second alignment pattern AP2 that is a hollow figure. That is, in the first alignment pattern AP1, the spatial frequency spectrum is biased toward the low frequency side. In the precision alignment operation described later, the position of each alignment pattern is detected using this feature.

  FIG. 8 is a diagram showing the arrangement of alignment marks for precision alignment operation. The substrate SB and the blanket BL are plate-like bodies having substantially the same plane size, and alignment marks are respectively formed at positions corresponding to each other when they are overlapped. That is, an effective pattern region PR that finally functions as a device is formed by forming a predetermined pattern such as a circuit pattern in the center of the plate-like substrate SB. The surface area of the blanket BL corresponding to this is the effective pattern area PR of the blanket BL, and the pattern to be transferred to the substrate SB is patterned into this area PR by the plate PP. In the example of FIG. 8, the rectangular area at the center of the rectangular substrate SB is used as the effective pattern area PR. However, these shapes are not limited to the rectangle but are arbitrary.

  And the area | region which adjoins the corner | angular part of the board | substrate SB outside the four corners of the effective pattern area | region PR is made into the alignment mark formation area AR. Note that the quartz windows 52a provided on the suction plate 51 of the lower stage unit 5 are respectively provided at positions corresponding to the four alignment mark formation areas AR described above.

  In the substrate SB, the first alignment marks AM1 are formed in advance in each of the four alignment mark formation areas AR by, for example, a photolithography technique. On the other hand, the second alignment mark AM2 formed in each alignment mark formation region AR of the blanket BL is patterned with a pattern formation material using a plate PP together with a pattern formed in the effective pattern region PR. Therefore, regardless of the positional relationship between the plate PP and the blanket BL during patterning, the positional relationship between the pattern formed in the effective pattern region PR and the alignment mark formed in the alignment mark formation region AR on the blanket BL is unchanged. is there. Thereby, the positional relationship between the substrate SB and the pattern on the blanket BL is kept constant by the alignment using the alignment mark. Therefore, precise alignment between the plate PP and the blanket BL is not always necessary.

  In this embodiment, the alignment pattern configured as described above is imaged by the imaging unit 43 of the alignment unit 4, the alignment pattern is detected from the captured image, and the substrate SB and the blanket BL (strictly, the pattern on the blanket BL). ) And an adjustment operation for aligning these positions as necessary.

  The first alignment mark and the second alignment mark of the present embodiment each include one or a plurality of the above-described alignment patterns as constituent elements. However, the precision alignment operation itself of the present embodiment is also realized by an alignment mark consisting of only a single alignment pattern. Therefore, here, alignment is performed using an example in which a first alignment mark composed of a single first alignment pattern AP1 is formed on the substrate SB, and a second alignment mark composed of a single second alignment pattern AP2 is formed on the blanket BL. The principle of operation will be described.

  FIG. 9 is a diagram illustrating an example of an image captured by a CCD camera. As shown in FIG. 9A, the captured image IM includes a second alignment pattern AP2 that is captured with high image contrast in a focused state. Therefore, it is relatively easy to detect the gravity center position G2m of the second alignment pattern AP2 from the captured image. When the second alignment pattern AP2 is an annular rectangular hollow figure, for example, the position of the center of gravity can be obtained as follows. As shown in FIG. 9B, the edge portion of the second alignment pattern AP2 is extracted by binarizing the luminance at each position in the image with a predetermined threshold, and the contour of the second alignment pattern AP2 is extracted from this. The position of the center of gravity G2m can be obtained by estimation. In particular, since the features such as the external dimensions and the line width of the pattern are known in advance, the image processing unit 65 can apply image processing specialized to those features.

  On the other hand, the first alignment pattern AP1 formed on the substrate side is not necessarily in focus. If the distance between the first alignment pattern AP1 and the second alignment pattern AP2 in the optical axis direction is equal to or smaller than the depth of field of the objective lens 435, both the first alignment pattern AP1 and the second alignment pattern AP2 are in focus. Images can be taken. However, when the interval between the alignment patterns is larger than the depth of field of the objective lens 435, if the second alignment pattern AP2 is focused, the first alignment pattern AP1 is out of the depth of field and cannot be focused. The image is taken as a blurred outline.

  In the present embodiment, an objective lens 435 having a magnification of about 5 times is used, and its depth of field is about ± 30 μm (60 μm as a focusing range). On the other hand, the gap Gsb between the substrate SB and the blanket BL set in the apparatus 100 is about 300 μm after the gap adjustment. Under such conditions, it is impossible to focus on both alignment patterns simultaneously. That is, if the second alignment pattern AP2 is focused, the first alignment pattern AP1 is not necessarily focused. The precision alignment method of the present embodiment enables highly accurate alignment corresponding to such a case.

  When the first alignment pattern AP1 is not in focus, as shown in FIG. 9A, the first alignment pattern AP1 is larger than the original outer shape indicated by a broken line, and the image is taken with a blurred outline. . Therefore, a relatively high frequency component is lost among the spatial frequency components that the shape of the original first alignment pattern AP1 had. For this reason, it is considered that the method of extracting an edge as in the case of the second alignment pattern AP2 is difficult to apply and the detection error increases. Therefore, as shown in FIG. 9C, the position of the center of gravity of the first alignment pattern AP1 is obtained from the peak position of the luminance level.

  At this time, as shown in FIG. 7C, the shape of the first alignment pattern AP1 includes a lot of low spatial frequency components in advance, thereby suppressing loss of image information and lowering the detection accuracy of the center of gravity position. Can be suppressed. In particular, when performing image processing with shading correction, low frequency components are also lost thereby, so it is effective to use a pattern having a shape in which the spatial frequency distribution approaches the low frequency side.

  In addition, since it is known in advance that the high-frequency component included in the original shape is lost, the high-frequency component has no utility in detecting the position of the center of gravity, but rather acts as noise. Therefore, it is desirable to perform a low-pass filtering process that removes high-frequency components from the image and detect the position of the center of gravity from the image after removal. In this way, the position of the center of gravity G1m of the first alignment pattern AP1 that is not in focus is detected.

  As shown in FIG. 9A, when the center of gravity position G1m of the first alignment pattern AP1 is used as a reference, for example, when the positional relationship between the substrate SB and the blanket BL is appropriate, the second alignment pattern AP2 is The position of the center of gravity to be located is represented by the symbol G2t. However, the position of the measured center of gravity G2m does not necessarily match this, and a precise alignment operation is required to match these positions. That is, in the precision alignment operation, as indicated by an arrow in the drawing, the relative position between the substrate SB and the blanket BL is adjusted so that the center of gravity position G2m of the detected second alignment pattern AP2 matches the appropriate position G2t. In this embodiment, the required amount of movement of the stage top 422 of the alignment stage 42 is calculated based on the imaging result and moved, so that the lower stage unit 5 supported by the stage top 422 and the blanket BL placed thereon Is moved to align the substrate SB.

  FIG. 10 is a flowchart showing a flow of processing of the precision alignment operation. This process is performed as part of the process of step S9 in FIG. First, the focus of the CCD camera 430 provided in the imaging unit 43 is adjusted to the alignment mark formation surface (upper surface) of the blanket BL by the precision lifting table 432 (step S901). Since the thickness of the blanket BL varies due to swelling, the focus needs to be performed every time the transfer process is executed.

  Specifically, focusing can be performed by, for example, the following autofocus (AF) adjustment operation. In other words, the CCD camera 430 is moved in the vertical direction (Z direction) by the precision lifting table 432 to change the focal position in the Z direction at a constant pitch, and the CCD camera 430 performs imaging each time. Then, a position at which the image contrast is maximized is calculated from the image of the alignment pattern AP2 to be imaged, and the focal position of the objective lens 435 is adjusted to that position. The four CCD cameras 430 are individually focused, but the processing contents are the same.

  FIG. 11 is a flowchart showing the focusing operation. First, the height of the CCD camera 430, that is, the position in the Z direction is set to a predetermined initial value by the precision lifting table 432 (step S911). Then, while the height of the CCD camera 430 is changed and set in multiple stages by the precision lifting table 432, the second alignment pattern AP2 is imaged by the CCD camera 430 each time (step S912). This is repeated until the CCD camera 430 reaches a predetermined final height (step S913). In this embodiment, the CCD camera 430 is moved in steps of 20 μm within a range of ± 100 μm from a predetermined standard height, and imaging is performed at each position.

  Of the original images picked up at each height in this way, the one in which the second alignment pattern AP2 is most clearly reflected is the state in which the focus of the CCD camera 430 matches (or is closest to) the second alignment pattern AP2. Represents. Therefore, by finding such an image and setting the CCD camera 430 at a height corresponding to the image, the purpose of focusing is achieved.

  However, since the second alignment pattern AP2 is formed of the same material as the pattern to be transferred to the substrate SB, it is not always possible to image with good contrast. For example, when the second alignment pattern AP2 is formed of a material having optical characteristics (particularly refractive index, reflectance, etc.) approximate to the blanket BL, only a low image contrast can be obtained even if the imaging conditions are finely adjusted. Sometimes.

  Further, in a state where the substrate SB and the blanket BL are arranged very close to each other, a relatively bright image can be obtained by the illumination light from the light source 463 being reflected by the substrate SB. On the other hand, for example, when the distance between the substrate SB and the blanket BL is relatively large as in the state where the gap adjustment between the substrate SB and the blanket BL is not completed, it is behind the blanket BL when viewed from the CCD camera 430 side. Since the substrate SB is far away, a sufficient amount of reflected light cannot be obtained, resulting in a dark and low contrast image. The same applies when the reflectance of the substrate SB itself is low.

  As described above, there are cases where it is not possible to expect the second alignment pattern AP2 to be imaged in a favorable environment when the focus is not yet achieved, and it is difficult to detect the second alignment pattern AP2 from the image. There is. However, it is necessary to reliably focus even in such an environment. In order to make this possible, in this embodiment, the following is performed.

  In the CCD camera 430 of this embodiment, the size of one pixel of the image sensor is about 0.7 μm. On the other hand, as shown in FIG. 7B, the line width of the second alignment pattern AP2 is 10 μm, which corresponds to about 14 pixels of the image sensor. Therefore, even in a low-contrast image, it is possible to more easily detect the second alignment pattern AP2 from the image by enhancing the spatial frequency component corresponding to 14 pixels corresponding to this line width. is there. This is because the shape and size of the second alignment pattern AP2 are known, and in this case, the detection of the second alignment pattern AP2 from the captured image only needs to be specified.

  For example, by removing a spatial frequency component corresponding to a size that is sufficiently finer than the line width, for example, less than half of the line width, noise components, particularly high-frequency random numbers, are lost without losing information about the edges of the second alignment pattern AP2. Noise components can be removed. Further, by removing a spatial frequency component corresponding to a size that is sufficiently larger than the line width, for example, twice or more the line width, the information on the edge of the second alignment pattern AP2 is also lost on a larger scale. It is possible to eliminate the influence of shading, for example, shading.

  Specifically, for the original image captured at each height, the image processing unit 65 sets a predetermined pixel unit based on the pattern shape of the second alignment pattern AP2, specifically, the number of pixels corresponding to the line width. Is equal to or less than half (for example, 4 pixels × 4 pixels) (step S914). Here, the image data after the averaging compression is referred to as first data. By performing averaging compression in this way, high frequency components included in the original image are removed, and in particular, random noise components are effectively removed. That is, the averaging compression process substantially corresponds to a low-pass filtering process. In addition, there is an effect of reducing the amount of data in subsequent calculations.

  Next, the first data after the averaging compression is subjected to averaging compression in a predetermined pixel unit, for example, 7 pixels × 7 pixels (step S915). Here, “pixel” means a pixel in the first data compressed in units of 4 pixels, and therefore 7 pixels here correspond to 28 pixels in the original image (that is, twice the line width). . Thereby, a low-frequency component that does not depend on the second alignment pattern AP2, for example, a variation due to shading is extracted. This is the second data.

  Subsequently, by taking a ratio between the first data and the second data, the influence of shading is eliminated from the first data. That is, the process for obtaining this ratio is substantially equivalent to a high-pass filtering process for removing a fluctuation component at a low frequency. As a result, only the spatial frequency component in the band centered on the component corresponding to the line width of the second alignment pattern AP2 is extracted. That is, the spatial frequency component corresponding to the line width of the second alignment pattern AP2 is extracted by the band pass filter. By multiplying the value of the ratio thus obtained by a predetermined enhancement coefficient K greater than 1, an image in which the contrast of the image element corresponding to the line width of the second alignment pattern AP2 in the original image is enhanced (step). S916).

  FIG. 12 is a diagram illustrating an example of image data with contrast enhancement. This figure shows the relationship between the position on one line drawn in the image obtained by imaging the second alignment pattern AP2 and the pixel value. Reference numeral (A) represents image data of the original image. The data includes noise, and a contrast sufficient to find the position of the second alignment pattern AP2 is not obtained in the original image. The code (B) represents the first data, and the high-frequency noise component is largely removed by the low-pass filter processing, but more gradual fluctuation due to shading is observed. The code (C) represents the second data, and only low frequency fluctuations due to shading appear.

  Reference numeral (D) represents data after contrast enhancement, and the peak at a position corresponding to the edge of the second alignment pattern AP2 is clearly obtained by removing the low frequency fluctuation due to shading and enhancing the contrast. Can be recognized. The clearer the second alignment pattern AP2 that appears in the image, the clearer this peak appears. By utilizing this fact, the second alignment pattern AP2 can be detected from the image.

For example, in an image that does not include the second alignment pattern AP2 at all, no significant peak appears in the data after contrast enhancement (code (D)), and the pixel value of the entire image is a uniform value close to the average level Vavg. Become. On the other hand, the closer the focus of the CCD camera 430 is to the upper surface of the blanket BL, the larger the pixel value that appears from the average level Vavg. Therefore, the absolute value of the difference between the pixel value Vi for each position in the image and the average value Vavg is obtained, and the sum obtained by integrating the values in the image:
Σ | Vi−Vavg | (Formula 1)
The amount of deviation between the focus position of the CCD camera 430 and the blanket BL upper surface position can be evaluated by the magnitude of the value of. As the focus of the CCD camera 430 is closer to the upper surface of the blanket BL, the spatial frequency component corresponding to the second alignment mark AM2 included in the image increases, and accordingly, the value expressed by (Equation 1) increases. Therefore, the value obtained by (Equation 1) for each of the images taken with different heights of the CCD camera 430 is referred to as “AF evaluation value” here. Among these images, the height of the CCD camera 430 when an AF evaluation value is maximized, that is, an image including the largest amount of spatial frequency components corresponding to the second alignment mark AM2 is captured. It can be said that the focus is the height closest to the top surface of the blanket BL.

  The enhancement coefficient K can be an arbitrary value larger than 1, but naturally, the larger this value is, the stronger the contrast is enhanced, and the peak corresponding to the edge of the second alignment pattern AP2 is enhanced. In this case, it is feared that signals that are unrelated to the alignment pattern are emphasized, but according to the experiments by the inventors, there is no trouble that affects the accuracy at least with respect to the focusing operation. This is because signal processing specialized for the shape of the alignment pattern to be detected, that is, band-pass filter processing for extracting a band corresponding to the spatial frequency component characterizing the second alignment pattern AP2, is independent of the alignment pattern. This is probably because the signal is sufficiently reduced.

On the other hand, it is impossible in principle to enhance the contrast beyond the dynamic range that the CCD camera 430 originally has. In this respect, the upper limit of the appropriate value of the enhancement coefficient K is determined. For example, in an imaging system in which the average amplitude of random noise with respect to the maximum output signal is N%, an appropriate maximum value Kmax of the enhancement coefficient K is expressed by the following formula:
Kmax = 100 / 4N (Formula 2)
Given by. This is because when noise with an amplitude of ± N% is emphasized to (100 / 2N) times, the noise component alone reaches 100%, and in practice, a signal having an S / N ratio of less than 2 times. Is derived from the experimental fact that it is difficult to separate the noise from the noise. For example, in an imaging system in which the ratio of random noise to signal is 1%, the upper limit value of the enhancement coefficient K is 25.

  Returning to FIG. 11, the AF evaluation value defined by (Equation 1) is calculated based on the above principle from the image data at each height enhanced in contrast by the processing up to step S916 (step S917). Then, the height of the CCD camera 430 is set to the height corresponding to the image having the maximum AF evaluation value (step S918). As a result, the focus position of the CCD camera 430 is substantially aligned with the upper surface of the blanket BL.

  Returning to FIG. 10, the description of the precision alignment operation will be continued. When the focus adjustment is performed in this way, the first alignment pattern AP1 and the second alignment pattern AP2 corresponding to the first alignment pattern AP1 are included in the field of view of each CCD camera 430, and the second alignment pattern AP2 is in focus. It is. Each CCD 430 captures this image and sends the image data to the image processing unit 65 (step S902). The image processing unit 65 performs predetermined image processing on the image thus captured, and detects the positions of the first and second alignment patterns AP1 and AP2 in the image (steps S903 and S904). Specifically, the center of gravity positions G1m and G2m are detected.

  When the positions of the center of gravity G1m of the first alignment pattern AP1 and the center of gravity G2m of the second alignment pattern AP2 are detected as described above, the amount of misalignment between them is subsequently calculated (step S905). What should be calculated here is not the amount of misalignment between the centroids G1m and G2m of the two detected alignment patterns, but the appropriate centroid position of the second alignment pattern AP2 derived from the centroid position G1m of the first alignment pattern AP1. This is the amount of displacement between G2t and the center of gravity position G2m of the second alignment pattern AP2 detected by actual measurement. When the first and second alignment patterns are arranged so that their center of gravity positions are common (that is, G2t is equal to G1m), naturally the positions between the center of gravity G1m and G2m of each of the two alignment patterns. The amount of deviation is the amount to be obtained.

  Note that the positional deviation that occurs between the substrate SB and the blanket BL in the XY plane includes not only deviation in the X direction and Y direction, but also twist, that is, a type of deviation in which the rotation angles around the vertical axis are different from each other. . In the adjustment of the center of gravity position of the pair of alignment patterns provided on each of the substrate SB and the blanket BL, it is difficult to correct the shift in the rotation direction around the vertical axis (hereinafter referred to as “θ direction”). In particular, when one of the alignment patterns is captured in an out-of-focus state, it is difficult to grasp the rotation angle of the pattern from a blurred image.

  In this embodiment, a pair of alignment marks is provided at each of the four corners of the substrate SB and the blanket BL (FIG. 8), and these are imaged by the four image capturing units 43. Then, the stage top 422 is moved in the X, Y, and θ directions so that the positional deviations in the X, Y, and θ directions obtained from the images captured by the four image capturing units 43 are averagely corrected. Determine the amount comprehensively. In this way, highly accurate alignment between the substrate SB and the blanket BL is possible.

  For each of the substrate SB side and the blanket BL side, when the gravity center position of the alignment pattern imaged by each camera is obtained by image processing by the image processing unit 65 (steps S903 and S904), from these calculation results, the substrate SB and The amount of positional deviation from the blanket BL is calculated (step S905). The amount of misregistration here is calculated for each of the X direction, the Y direction, and the θ direction. If the positional deviation amount thus obtained is within the predetermined allowable range (step S906), the positional deviation between the substrate SB and the blanket BL can be ignored, and the precision alignment operation is terminated.

  When the amount of positional deviation exceeds the allowable range, it is necessary to move the blanket BL to correct this. Next, move for that purpose, but considering that there is a possibility that alignment is not possible due to some device malfunction, set an upper limit for the number of movement retries for alignment deep. That is, when the number of retries reaches a predetermined number set in advance (step S907), a predetermined error stop process is executed (step S908), and the process ends. The contents of this error stop process include, for example, displaying a predetermined error message and completely stopping the process itself, informing the user of the error contents, and waiting for the user's instructions for the subsequent processes. It is done. The processing may be resumed according to a user instruction.

  On the other hand, if the predetermined number of retries has not been reached (step S907), the amount of movement of the blanket BL necessary for alignment is calculated (step S909), and the alignment stage 42 is operated based on the calculated amount of movement. (Step S910), the position of the blanket BL is moved together with the stage top 422. In this state, imaging of each alignment pattern and detection of the center of gravity position are performed again to determine whether or not the blanket BL needs to be moved again (steps S902 to S906). This is repeated until a predetermined number of retries is reached (step S907).

  Thereby, in each of the images picked up by each CCD camera 430, the positional relationship between the first alignment pattern AP1 and the second alignment pattern AP2 matches a preset relationship (for example, FIG. 9A). Alternatively, the amount of positional deviation from this relationship falls within the allowable range. Thus, the alignment (precision alignment) between the substrate SB and the blanket BL is completed.

  After the alignment process is completed in this way, air is sent between the suction plate 51 and the blanket BL, whereby the central portion of the blanket BL rises and comes into close contact with the substrate SB, and the pattern carried on the blanket BL is applied to the substrate SB. Transcribed. At this time, the second alignment mark AM2 formed on the surface of the blanket BL with the same material as the pattern is also transferred to the substrate SB together with the pattern. At the end of precision alignment, the second alignment mark AM2 is in a position substantially opposite to the first alignment mark AM1 on the substrate SB. Therefore, when the blanket BL is in contact with the substrate SB as it is, the second alignment mark AM2 is It is transferred in the vicinity of the alignment mark AM1.

  The transfer of the pattern onto the substrate SB is repeatedly performed a plurality of times as necessary. Naturally, the alignment process described above is necessary each time. For this reason, every time pattern transfer is performed, the second alignment mark formed with the pattern is transferred to the substrate SB. At this time, the second alignment mark transferred earlier may become an obstacle to the alignment operation for the subsequent transfer process. The arrangement of alignment marks (FIG. 7) in the present embodiment takes into account such a problem.

  FIG. 13 is a diagram for explaining the arrangement of alignment marks. As shown in FIG. 13A, the alignment mark AM1 on the substrate SB is one in which four first alignment patterns AP11 to AP14 are arranged so that each has a square apex. The second alignment mark AM21 transferred from the blanket BL to the substrate SB by the first transfer process is surrounded by these four first alignment patterns AP11 to AP14, and spaced apart from each of the first alignment patterns AP11 to AP14. The image is transferred to the inner side (alignment mark transfer region) TR.

  Even in the alignment process prior to the second transfer process, the blanket BL is focused as described above. At this time, as shown in FIG. 13B, the image of the second alignment mark AM21 carried on the blanket BL at this time is clear, but the first alignment patterns AP11 to AP12 on the surface of the substrate SB and Since the second alignment mark AM21 transferred to the surface of the substrate SB is not in focus, it is unclear.

  At this time, if the second alignment mark AM21 appearing indistinctly overlaps or is very close to any of the first alignment patterns AP11 to AP14 and the second alignment mark AM22, the calculation of the center of gravity position is affected. As a result, the alignment accuracy of the alignment process may be reduced. In particular, if such a detection error is included in the processing step (step S906 in FIG. 10) for determining whether or not the precision alignment operation has converged, the alignment processing ends with the positional deviation remaining.

In order to avoid such a problem, in this embodiment,
(1) The second alignment mark AM2 on the blanket BL is transferred to a position separated from the first alignment mark on the substrate SB by a certain distance or more.
(2) The second alignment marks AM2 transferred from the blanket BL to the substrate SB by a plurality of pattern transfers are transferred at different positions and at a sufficient distance from each other.
(3) In order to improve alignment accuracy, in each alignment process, the first alignment pattern AP1 on the substrate SB side and the second alignment mark AM2 on the blanket BL side are arranged as close as possible.
Designing alignment marks based on this design concept.

  That is, the requirement (1) is satisfied by limiting the transfer position of the second alignment mark AM2 to the alignment mark transfer region TR that is distant from the first alignment patterns AP11 to AP14. Since there is a case where the apparent size of the images of the first alignment patterns AP11 to AP14 and the transferred second alignment mark AM2 becomes larger than the actual size (for example, up to about 2 times) due to the imaging in the out-of-focus state. It is desirable that the distance between the first alignment pattern AP11 to AP14 and the second alignment mark AM2 transferred to the alignment mark transfer region TR is as large as possible. Practically, the position of the first alignment pattern AP11 to AP14 and the transfer position of the second alignment mark AM2 in each transfer are at least the outer dimension (50 μm) of the first alignment pattern AP1 and the second alignment mark AM2. It is necessary that the distance is larger than half the sum (85 μm) of the outer dimension (120 μm). In this embodiment, as shown in FIG. 13B, this distance is set to 115 μm.

  Further, in order to satisfy the requirement (2), the position of the second alignment mark AM2 carried on the blanket BL is made different for each transfer, and the change amount of the position is made sufficiently large. Good. Further, in order to satisfy the requirement (3), the plurality of first alignment patterns AP1 are arranged separately, and the second alignment mark AM2 to be newly transferred can be arranged close to at least one of them. You can do it.

  In view of these, in this embodiment, the first alignment mark AM1 in which the four first alignment patterns AP11 to AP14 are arranged so as to surround the alignment mark transfer region TR to which the second alignment mark AM2 is transferred is set. In the alignment mark transfer region TR, as shown by a dotted line in FIG. 13B, a space in which up to nine second alignment marks AM2 can be transferred is secured. Therefore, pattern transfer of up to 9 times is possible. Further, the transfer pitch between the second alignment marks in the transfer region TR is set to 200 μm so that the second alignment mark AM22 to be newly transferred does not overlap the image of the transferred second alignment mark AM21. The first alignment mark AM1 shown in FIG. 7A is configured in this way.

  A specific procedure for performing the alignment process for each of a plurality of transfers using the first alignment mark AM1 configured as described above is as follows. In the precise alignment operation of FIG. 10, when the imaging of the alignment mark and the movement of the alignment stage 42 based on the alignment mark converge, the second alignment mark AM2 on the surface of the blanket BL is first in the alignment pattern transfer region TR of the substrate SB. It is made to oppose the area | region except the area | region where 2nd alignment mark AM2 was transcribe | transferred. In other words, the target center of gravity position (reference symbol G2t in FIG. 9A) of the second alignment mark AM2 is set so that the positional relationship between the first alignment mark AM1 and the second alignment mark AM2 becomes such a precise alignment. Operation is performed. Thus, the second alignment mark AM2 is positioned with respect to the first alignment mark AM1, and the second alignment mark AM2 is finally transferred to the substrate SB.

  In a plurality of pattern transfers, the target center-of-gravity position of the second alignment mark AM2 is changed little by little every precision alignment operation prior to each pattern transfer. That is, the target center-of-gravity position is set in an area separated from the area where the second alignment mark AM2 has been previously transferred in the alignment pattern transfer area TR of the substrate SB. At this time, the positional relationship between the pattern on the blanket BL and the second alignment mark AM2 is adjusted in advance so that the positional relationship between the substrate SB and the pattern does not shift. That is, a plate PP is formed on the blanket BL so that the pattern and the second alignment mark AM2 are formed on the blanket BL in such a positional relationship.

  The target center-of-gravity positions of the second alignment marks AM2 corresponding to each of the plurality of transfer processes are second with respect to each other in consideration of misalignment in a range allowed in precision alignment and spread in a state where the focus is not achieved. It is set with a distance larger than the outer dimension of the alignment mark AM2. In this embodiment, the pitch of the target gravity center position is set to 200 μm with respect to the second alignment mark AM2 having one side of 120 μm.

  Thus, precise alignment is performed by changing the target position of the second alignment mark for each transfer in the alignment transfer region TR, and the second alignment mark AM2 is transferred to the substrate SB along with the pattern transfer. The second alignment mark AM2 is formed on the surface of the substrate SB facing the second alignment mark AM2 after the fine alignment, that is, on the region where the second alignment mark is not transferred in the alignment mark transfer region TR, and the second alignment has been transferred. Transferred separately from the mark.

  In this way, in each transfer process, at least one of the first alignment patterns AP11 to AP14 formed on the substrate SB with the second alignment mark AM2 carried on the blanket BL is applied to the same field of view of the CCD camera 430. The image can be picked up and alignment can be performed with high accuracy based on the image. At this time, the image of the second alignment mark transferred onto the substrate SB in the previous transfer process is prevented from interfering with the image of the second alignment mark AM2 on the surface of the blanket BL. In addition, high positional accuracy can be maintained between the patterns transferred each time.

  A specific operation when performing pattern transfer a plurality of times on the same substrate can be performed as follows, for example. One aspect thereof is that all of the processing steps (S1 to S14) shown in FIG. 4 are repeated a plurality of times. That is, the plate PP, the substrate SB, and the blanket BL are loaded into the printing apparatus 100 (steps S1, S2, and S4) and removed from these apparatuses (steps S12 to S14) by repeating each transfer. Do. In this case, the plate PP, the substrate SB, and the blanket BL can be exchanged for each transfer, so that their combination and transfer order can be arbitrarily set.

  Another aspect of the multiple pattern transfer is to perform multiple pattern transfers on the substrate SB while leaving the substrate SB once carried in the printing apparatus 100. In this case, in the first operation, the above-described steps S1 to S13 are executed, and then the operation from step S1 is executed again. However, step S2 is omitted at this time. Then, after all the patterns have been transferred, the substrate SB is taken out (step S14).

  In this way, the number of times the substrate SB is carried into and out of the printing apparatus 100 (including the holding and releasing operation associated therewith) can be reduced, and a plurality of the substrates SB can be performed in a short time with respect to one substrate SB. Pattern transfer can be performed.

  In these two modes of operation, it is desirable that the plate PP and the blanket BL are transported and washed to the knowledge that transfer is completed, but the plate PP and the blanket BL used in the next operation are the same as the previous one. Or different ones. In any case, since the relative position may change due to the positional deviation at the time of mounting or the blanket BL swelling, the focusing operation and the alignment process described above need to be executed every time pattern transfer is performed.

  Further, it is not essential that a plurality of pattern transfers be performed by the same printing apparatus 100. That is, a new pattern is transferred to the substrate SB when at least one layer of the patterned substrate SB is carried into the printing apparatus 100 and the above operation is executed, but how the previous pattern is formed. Regardless of whether or not it has been done, it is possible to form a new pattern using the printing apparatus 100 of the present embodiment.

  As described above, in this embodiment, before the pattern carried on the blanket BL is transferred to the substrate SB, the alignment marks formed on the respective patterns are imaged, and the blanket BL and the substrate SB are based on the imaging result. Alignment processing for performing alignment with is executed. At this time, the first alignment mark AM1 formed on the substrate SB side is a plurality of figure (here square) patterns AP1 spaced apart, and the surface region of the substrate SB surrounded by the plurality of patterns is: This is an alignment mark transfer region TR to which the second alignment mark AM2 carried on the blanket BL side is transferred.

  In the precision alignment operation, the substrate SB and the blanket BL are aligned so that the center of gravity of the second alignment mark AM2 matches the target center of gravity G2t set in the alignment mark transfer region TR. In a plurality of precision alignment operations corresponding to each of the plurality of pattern transfers, the target center of gravity position of the second alignment mark AM2 is transferred within the alignment mark transfer region TR and the second alignment marks are separated from each other. Is set to In other words, the plurality of second alignment marks AM2 corresponding to each of the plurality of times of pattern transfer are separated from each other and can be separated from each first alignment pattern AP1 constituting the first alignment mark AM. The first alignment mark AM1 is designed so that the mark transfer region TR is secured.

  Therefore, in the precision alignment operation corresponding to each pattern transfer, the first alignment mark AM1 previously formed on the substrate SB in the captured image, and the second alignment mark transferred from the blanket BL to the substrate SB in the previous transfer (For example, the symbol AM21 in FIG. 13B) and the second alignment mark (for example, the symbol AM22 in FIG. 13B) formed on the blanket BL for the current precise alignment operation interfere with each other. Therefore, each position can be detected with high accuracy.

  Therefore, in this embodiment, alignment between the substrate SB and the pattern carried on the blanket BL can be performed with high accuracy. In this state, the substrate SB and the blanket BL are brought into contact with each other, so that the pattern can be transferred with high accuracy to a predetermined position of the substrate SB.

  In particular, when the CCD camera 430 is focused on the blanket BL surface, images of the first alignment mark AM1 and the transferred second alignment mark AM21 on the surface of the substrate SB that are not in focus are blurred and larger than actual. Although it may spread, it is avoided that the alignment accuracy is reduced due to the above-mentioned phenomenon due to the design of the alignment mark and the precise alignment operation in consideration of the influence.

  As described above, in this embodiment, the blanket BL corresponds to the “supporting body” of the present invention. In the above embodiment, the upper stage portion 3 and the lower stage portion 5 function as the “transfer means” of the present invention. The imaging unit 43 functions as the “imaging unit” of the present invention. Further, the image processing unit 65 and the alignment stage 42 are integrated to function as the “alignment means” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the shape of the alignment mark shown in the above embodiment is merely an example, and various other shapes can be employed. However, it is desirable that the spatial frequency component of the image of the alignment mark is characteristic so that detection is easy even from the imaging result in a state where the focus is not achieved as described above.

  That is, the first alignment mark AM1 formed on the substrate SB includes a relatively low frequency component so that the position of the center of gravity can be accurately detected even when the focus is not achieved. It is preferable that the figure is point-symmetric with respect to the rotation angle. Further, the second alignment mark AM2 formed on the blanket BL has a relatively high frequency component and has a characteristic portion that can be extracted by a narrow-band bandpass filter process. It is desirable to increase

  In the above embodiment, focusing is performed by moving the entire CCD camera 430 up and down with the precision lifting table 432, but instead, an imaging optical system composed of a plurality of lenses is provided to provide a space between the lenses. Focusing may be performed by adjusting the distance.

  In the above embodiment, four sets of alignment marks are formed in the vicinity of the four corners of the substrate SB and the blanket BL, but the number of alignment marks formed is not limited to this and is arbitrary. However, in order to appropriately correct the positional deviation around the vertical axis, it is preferable to use a plurality of sets of alignment marks formed at different positions, and it is more desirable that these are located as far as possible. In addition, in order to suppress an error due to the positional deviation of each camera, it is desirable to provide three or more sets of alignment marks.

  In the above embodiment, the alignment mark on the blanket BL is formed of the same material as the pattern forming material. However, this is not an essential requirement. For example, an alignment mark that is not transferred to the substrate is formed on the blanket BL in advance. You may keep it. In this case, in order to perform pattern transfer onto the substrate SB with high positional accuracy, the positional accuracy of the pattern carried on the blanket BL is important. Therefore, when performing patterning on the blanket BL with the plate PP, It is necessary to perform alignment with the blanket BL more precisely.

  In the above embodiment, the alignment mark transfer region TR to which a maximum of nine second alignment marks AM2 can be transferred is provided on the substrate SB. However, the number of second alignment marks AM2 transferred to the substrate SB, that is, the substrate SB. The number of times of pattern transfer onto the substrate SB is arbitrary. For example, even when the pattern transfer onto the substrate SB is performed only once, the above-described focusing operation functions effectively.

  Moreover, in the said embodiment, although patterning to blanket BL is performed inside the printing apparatus which is one embodiment of the transfer apparatus of this invention, this invention is not limited to this, For example, patterning is performed outside. The present invention can also be suitably applied to an apparatus in which a blanket is carried and a pattern is transferred onto a substrate.

  The present invention can be suitably applied to a technical field that requires high-precision alignment between a carrier carrying a pattern and a substrate onto which the pattern is transferred.

3 Upper stage (transfer means)
4 Alignment section 5 Lower stage section (transfer means)
42 Alignment stage (alignment means)
43 Imaging unit (imaging means)
65 Image processing unit (alignment means)
100 Printing device (transfer device)
430 CCD camera AM1 1st alignment mark AM2 2nd alignment mark BL Blanket (carrier)
SB substrate TR alignment mark transfer area

Claims (7)

In a transfer method for transferring a pattern or a thin film as a transfer object from a carrier supporting the transfer object to a predetermined position on a substrate,
The substrate having the first alignment mark formed on the surface, and the light-transmitting carrier that supports the transferred object and the second alignment mark formed on the surface with the transferred object using the same material as the transferred object. And a holding step of holding the alignment mark forming surfaces close to each other in a state of facing each other,
An imaging step of imaging the first alignment mark and the second alignment mark in the same field of view of the imaging means from the opposite side of the carrier to the alignment mark formation surface;
A position detection step of detecting positions of the first alignment mark and the second alignment mark based on the captured image;
An alignment step of adjusting a relative position between the substrate and the carrier based on a detection result in the position detection step;
A transfer step in which the substrate whose relative position is adjusted in the alignment step and the carrier are brought into contact with each other, and the transfer object and the second alignment mark on the surface of the carrier are transferred to the substrate;
The first alignment mark formed on the substrate includes a plurality of graphic patterns spaced apart from each other, and the plurality of graphic patterns can be arranged with the second alignment mark spaced from each of the graphic patterns. Arranged to surround the alignment mark transfer area,
In the alignment step, the relative position between the substrate and the carrier is adjusted, and the second alignment mark is positioned opposite to an area where the second alignment mark is not transferred in the alignment mark transfer area,
In the transfer step, the second alignment mark is transferred to the substrate separately from each of the plurality of graphic patterns in the alignment mark transfer region. A plurality of transfers of the object to be transferred from the carrier to the substrate are performed by performing a series of processes that sequentially execute the holding step, the imaging step, the position detection step, the alignment step, and the transfer step. Run times,
The first alignment mark has the alignment mark transfer region in which a plurality of the second alignment marks corresponding to a plurality of times of transfer can be arranged separately from each other,
2. The transfer method according to claim 1, wherein in each transfer step, the second alignment mark is transferred while being spaced apart from each other in the alignment mark transfer region. The graphic pattern of the first alignment mark contains more low spatial frequency components than the graphic pattern of the second alignment mark,
In the imaging step, focusing is performed on the second alignment mark carried on the carrier to perform imaging,
The transfer method according to claim 1, wherein, in the position detection step, a gravity center position of the graphic pattern of each of the first alignment mark and the second alignment mark is detected.   The transfer method according to claim 3, wherein the graphic pattern of the first alignment mark is a solid graphic, and the graphic pattern of the second alignment mark is a hollow graphic. In a transfer device for transferring a pattern or a thin film as a transfer object from a carrier carrying the transfer object to a predetermined position on a substrate,
The substrate having the first alignment mark formed on the surface, and the light-transmitting carrier that supports the transferred object and the second alignment mark formed on the surface with the transferred object using the same material as the transferred object. Are held close to each other with the alignment mark forming surfaces facing each other, and the carrier and the substrate are brought into contact with each other to transfer the transferred object and the second alignment mark from the carrier to the substrate. Transfer means for transferring to,
In a state where the substrate and the carrier are held close to each other by the transfer means, the first alignment mark and the second alignment mark are interposed via the carrier from the side opposite to the alignment mark forming surface of the carrier. Imaging means for imaging within the same field of view of the imaging means;
Alignment means for adjusting a relative position between the substrate and the carrier based on a position detection result of the first alignment mark and the second alignment mark in the captured image;
The alignment means adjusts the relative position between the substrate and the carrier, and the second portion of the alignment mark transfer region surrounded by a plurality of graphic patterns constituting the first alignment mark on the substrate surface. The second alignment mark is positioned opposite to an area where the alignment mark is not transferred,
The transfer device, wherein the transfer means transfers the second alignment mark to the substrate at a distance from each of the plurality of graphic patterns within the alignment mark transfer region. The transfer means holds the substrate on which the transferred object and the second alignment mark are transferred, and can transfer a new transferred object and the second alignment mark from the carrier to the substrate. ,
The alignment means adjusts the relative position between the substrate and the carrier, and positions the new second alignment mark so that the second alignment mark of the alignment mark transfer region is opposed to a region where the second alignment mark is not transferred,
The transfer means transfers the second alignment mark carried on the carrier to the substrate while being separated from each of the plurality of graphic patterns and the transferred second alignment mark in the alignment mark transfer region. The transfer device according to claim 5.   The imaging means focuses on the second alignment mark carried on the carrier to perform imaging, and the alignment means determines the position of the center of gravity of the graphic pattern of each of the first alignment mark and the second alignment mark. The transfer device according to claim 5, wherein a relative position between the substrate and the carrier is adjusted based on a detection result.

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