JP2011134946A - Stage apparatus, exposure apparatus using the same, and method of manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stage apparatus which prevents a gap from being generated between a supporting means that supports the rear surface of a holding means for holding a substrate, and the rear surface, when adjusting the flatness of the substrate. <P>SOLUTION: The stage apparatus includes: a bearing means which supplies air between the rear surface of the holding means and the supporting means so as to lift the holding means from the supporting means; a detecting means which detects the flow rate of the air supplied by the bearing means; and a control means which controls the drive of the supporting means. The control means controls the drive of the supporting means so that the flow rate detected by the detecting means falls within a predetermined flow rate range when the holding means is lifted by the bearing means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stage apparatus, an exposure apparatus that exposes a substrate using the stage apparatus, and a device manufacturing method.

  An exposure apparatus is used to project an original pattern onto a substrate such as a wafer. In recent years, however, the exposure apparatus is required to have a micron-order level accuracy as the pattern becomes finer. As miniaturization progresses, the depth of focus becomes shallow, and as a result, the flatness of the substrate surface required from the depth of focus also increases. Therefore, various ideas have been made to improve the flatness of the substrate surface and ensure imaging performance.

  For example, a technology is proposed that adjusts the flatness by displacing the substrate surface by driving a plurality of support units from the surface (back surface) opposite to the chuck holding surface of the substrate held by the chuck that is the substrate holding unit. (For example, refer to Patent Document 1).

  The driving of the support unit is performed by measuring the flatness of the substrate surface with a displacement sensor, calculating a driving amount for flattening the substrate surface from difference information from a predetermined ideal plane, and determining the supporting unit based on the driving amount. Drive. In addition, a support part is a diaphragm structure, contacts and supports the back surface, and performs flatness adjustment.

JP 2009-218372 A

  By the way, when a substrate is supplied onto the chuck, a placement error occurs. Therefore, it is necessary to adjust the position of the substrate before adjusting the flatness. The position adjustment of the substrate is performed by floating the entire chuck supplied with the substrate and rotating it in the circumferential direction (θ direction) of the axis orthogonal to the stage by the drive system. When this position adjustment is completed, the chuck is seated on the support portion, and the flatness is adjusted while holding the substrate. The chuck is lifted by a bearing (air bearing) that supplies gas to the back surface of the chuck and supports the chuck in a non-contact manner.

  When the position adjustment is completed and the chuck is seated on the support, contact is supported on the back of the chuck among the multiple supports due to differences in component tolerances and bending of the base on which the support is mounted. Something that doesn't happen. In other words, a gap is generated between the back surface of the chuck and the support portion even though the air bearing is not lifted. Even if the flatness adjustment is performed in such a state, the calculated driving amount is not properly transmitted to the support portion, and there is a problem that the flatness adjustment on the micron order cannot be performed. Further, even if a gap is generated, the substrate surface is not necessarily deformed immediately by this, and several hours may elapse before the substrate surface is deformed. For this reason, even if there is no problem when the substrate surface flatness is adjusted, the substrate surface may be deformed when the substrate is actually exposed, which may affect the exposure accuracy.

  Accordingly, an object of the present invention is to provide a stage device that prevents a gap from being formed between the support portion and the back surface of the chuck before the flatness of the substrate is adjusted.

  In order to solve the above-described problems, the present invention provides a stage apparatus including a holding unit that holds a substrate, and a support unit that supports the holding unit and drives the holding unit in a push-up direction with respect to a surface opposite to the holding surface. And a bearing means provided in the support means, for supplying a gas between the opposite surface and the support means, and for floating the holding means from the support means, and supplied from the bearing means. Detection means for detecting the flow rate of gas; and control means for controlling the drive of the support means. The control means is detected by the detection means when the holding means is levitated by the bearing means. The drive of the support means is controlled so that the flow rate of the support is within a predetermined flow rate range.

  According to the present invention, since the flatness adjustment is performed after confirming that all the support means are in contact with and supported by the back surface of the holding means holding the substrate, the flatness adjustment at the micron order level is highly accurate. The effect that it can be performed is produced.

It is a figure which shows schematic structure of the exposure apparatus provided with the stage apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the stage apparatus concerning embodiment of this invention. It is a figure which shows the processing flow of a control part. (A) It is a figure which shows the state which the location which the support part does not contact-support to the chuck base has arisen, (b) It is a figure which shows the state which all the support parts are contacting and supporting to the chuck base.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the following description, a specific configuration, operation, and the like are shown and described, but these can be changed as appropriate.

  FIG. 1 is a view showing a schematic configuration of an exposure apparatus provided with a stage apparatus according to an embodiment of the present invention.

  The exposure apparatus illuminates the pattern of the original M with the illuminating device 10, and projects light that reflects the pattern of the original M onto the substrate M on the substrate stage (stage 50 described later) via the projection optical system 30 for exposure. To do. The illumination device 10 includes a light source 11 that illuminates the original M and an illumination optical system 12 that uniformly illuminates the original M with light from the light source 11. The original M is placed on the original stage 20 and moved. The original stage 20 has an original stage surface plate 21 and an XYθ stage 22, the XYθ stage 22 is disposed on the original stage surface plate 21, and the original plate M is placed thereon. The original M can be moved in the X and Y directions and rotated in the XY plane by the XYθ stage 22. An observation optical system 13 is disposed above the original stage 20. The observation optical system 13 can observe the original M and the image on the substrate W formed through the projection optical system 30. The observation optical system 13 observes each reference mark (not shown) of the original M and the substrate W, and uses it for alignment between the pattern of the original M and the projection on the substrate W based on the positional deviation amount of both reference marks. Is done.

  Diffracted light emitted from the illuminating device 10 via the original M is projected onto the substrate W via the projection optical system 30. The original M and the substrate W are optically conjugate. In the exposure apparatus according to the present embodiment, each module functions as a scanner, and synchronously scans the original M and the substrate W at a speed ratio of a reduction magnification ratio. The original pattern is transferred to the substrate W by performing this synchronous scanning. The position of the original stage 20 is constantly measured by the interferometer 40. The optical element 31 of the projection optical system 30 projects light reflecting the pattern of the original M onto the substrate W. Note that immersion exposure may be realized by immersing the final optical element 32 closest to the substrate W of the projection optical system 30 in a liquid.

  The stage 50 is movable in the XYZ direction and the rotation (θ) direction using a linear motor, and moves while holding the substrate W via a chuck 56 as a holding means. The chuck 56 includes a chuck attachment 561 that sucks and holds the substrate W through a suction hole (not shown) that is evacuated and a chuck base 562 that supports the chuck attachment 561. Adsorption can be released by air blow operation of the chuck attachment 561.

  The stage 50 has a Y stage 52 and an X stage 53 disposed on the main body base 51. A θZ base 54 is mounted on the X stage 53 and the Y stage 52 via a Z tilt drive mechanism 55, and a plurality of support systems 60 (four in the present embodiment) are arranged thereon. The Z tilt drive mechanism 55 supports the mounted object on the θZ base 54 so as to be tiltable, and makes the surface of the substrate M coincide with the substrate-side focal plane (image plane) of the projection optical system 30 during exposure. The support system 60 includes a support portion 61, an air bearing 62 as a non-contact support bearing means provided at the tip of the support portion 61, and a pressurizing magnet 63. The plurality of support portions 61 adjust the flatness by contacting and supporting the chuck 56 holding the substrate M from the surface (back surface) opposite to the holding surface, that is, the chuck base 562. The portion of the support portion 61 that supports the contact is, for example, a diaphragm structure made of an elastic body. The movement of fluid is controlled via a piston by a driving source such as a motor (not shown), and the elastic body is driven in the pushing-up direction (Z direction) with respect to the chuck base 562 to be elastically deformed. Due to this elastic deformation, the support portion 61 contacts and supports the chuck base 562, and the flatness adjustment is performed by pushing up the bending of the substrate M and the like.

  The air bearing 62 is used to adjust the position of the substrate M before adjusting the flatness in order to correct a placement error that occurs when the substrate M is placed on the chuck 56. That is, in order to rotate the substrate M in the circumferential direction (θ direction) of the axis orthogonal to the stage 50, gas is supplied to the back surface, and the chuck 56 holding the substrate M is floated. The chuck 56 is brought into a non-contact support state by the air bearing 62, is rotated in the θ direction, the gas supply is stopped at a predetermined position, and the chuck 56 is seated on the support portion 61. The pressurizing magnet 63 generates an attractive force in a direction to be attracted to the stage 50 when ascending, and balances the pressure with the air bearing 62 to keep the ascending gap constant. The gas supplied from the air bearing 62 may be air or an inert gas, and is not particularly limited.

  The positions of the original stage 20 and the stage 50 are measured by the interferometer 40. The interferometer 40 includes a laser head 41 that is a light source for emitting detection light, a beam splitter 42, a bending mirror 43, and bar mirrors 44 and 45 that reflect detection light. The bar mirror 44 is fixed to the θZ base 54, and the bar mirror 45 is fixed to the original stage surface plate 21.

  FIG. 2 is a diagram showing a configuration around the substrate of the stage apparatus according to the embodiment of the present invention. In the flatness adjustment of the substrate M described with reference to FIG. 1, the drive amount of the support unit 61 by the drive source is determined by measuring the displacement of the substrate M. That is, it is measured by the displacement sensor 80 that measures the displacement of the surface of the substrate, and the driving amount of the support portion 61 is determined based on the measurement result data. The displacement sensor 80 is disposed so as to face each support portion 61 via the chuck 56 and can simultaneously read displacements at a plurality of locations by one measurement.

  By the way, when the substrate M is loaded onto the stage 50 and placed on the chuck 56, all the support portions 61 may not be in contact with and supported by the chuck base 562 due to a difference in tolerance of various parts, bending, or the like. Even if the flatness is adjusted in this state, it is not possible to adjust the micron-order level with high accuracy. In particular, even if the support portion 61 is not in contact support, it may take several hours until the portion is bent. In this case, since the displacement sensor 80 cannot measure the displacement of the surface of the substrate M, the exposure process is started without adjusting the flatness sufficiently.

  Therefore, the flow rate of each air bearing 62 described in FIG. 1 is detected, and control is performed so that each flow rate falls within a predetermined flow rate range. This control is performed by a control unit including a first control unit 71, a second control unit 72, and a calculation unit 74. The second controller 72 controls the flying and seating of the chuck 56 by the air bearings 62. The floating of the chuck 56 restricts the movement in the XY directions by the guide 90, and enables the driving in the θ direction and the driving of the flying or sitting only. When the chuck 56 is lifted by the second controller 72, each flow rate of each air bearing 62 is detected by the detector 73. If any one of the detected flow rates is out of the predetermined flow range, the control unit 74 generates a control signal for controlling the driving of the support unit 61 and transmits the control signal to the first control unit 71. To do. The first control unit 71 that has received this control signal drives the support unit 61 at a location where it is detected that the flow rate is outside the predetermined flow rate range according to the control signal. By controlling this drive, all the support portions 61 are supported by the chuck base 562 when the chuck 56 is seated, so that it is possible to adjust the flatness with high accuracy.

  FIG. 3 is a diagram illustrating a processing flow of the control unit. In order to adjust the position, the gas is supplied from the air bearing 62 toward the chuck base 562 by the second controller 72, and the chuck 56 is floated (S1). The flow rate of each air bearing 62 at this time is detected by the detector 73 (S2). It is determined by the calculation unit 74 whether or not each detected flow rate is within a predetermined flow rate range (S3). If the range of each flow rate is included in the predetermined flow rate range and becomes substantially uniform, it can be determined that all the support portions 61 can contact and support the chuck base 562 when the chuck 56 is seated. In addition, the form which detects each flow volume at this time may be sufficient as the chuck | zipper 56 which floated is seated. In this case, since the flow rate of the support portion 61 that supports the contact is zero, the predetermined flow rate range can be determined as a range including zero. On the other hand, when any one of the flow rates is out of the predetermined flow rate range (in the case of NO in S3), the calculation unit 74 controls the drive of the support unit 61 at the location determined to be out of the predetermined flow rate range. A control signal is generated.

  FIG. 4A shows a state where a portion where the support portion 61 does not contact and support the chuck base 562 is generated when the chuck 56 is seated. A gap is formed between the second support portion 61 and the chuck base 562 from the left in the front view of the drawing. At this time, the flow rate of the gas generated in this gap is detected by the detection unit 73 as described in S2. When this flow rate is outside the range of the predetermined flow rate, it can be determined that the gap exceeds the range in which the flatness adjustment can be appropriately performed by the support portion 61.

  The calculation unit 74 transmits the calculated control signal to the first control unit 71, and the first control unit 71 that has received the control signal drives the support unit 61 in the direction of pushing up the chuck base 562 (S4). The detection of S2 is performed again, and thereafter, the feedback control from S2 to S4 can be repeated until all the flow rates are within a predetermined flow rate range. When all the flow rates are within the predetermined flow rate range (YES in S3), the flatness adjustment of the chuck 56 is started (S5). FIG. 4B shows a state where all the support portions 61 are in contact with and supported by the chuck base 562 when the chuck 56 is seated. If the flatness is adjusted in this state, high-precision adjustment on the order of microns can be achieved.

  When the flatness adjustment is started in S5, the calculation unit 74 receives measurement result data obtained by measuring the displacement of the surface of the substrate M from the displacement sensor 80. The calculation unit 74 generates a control signal for controlling the support unit 61 based on the measurement result data, and transmits the control signal to the first control unit 71 to adjust the flatness.

  Next, a method for manufacturing a device (semiconductor device, liquid crystal display device, etc.) according to an embodiment of the present invention will be described. A semiconductor device is manufactured through a pre-process for producing an integrated circuit on a wafer and a post-process for completing an integrated circuit chip on the wafer produced in the pre-process as a product. The pre-process includes a step of exposing a wafer coated with a photosensitive agent using the above-described exposure apparatus, and a step of developing the wafer. The post-process includes an assembly process (dicing and bonding) and a packaging process (encapsulation). A liquid crystal display device is manufactured through a process of forming a transparent electrode. The step of forming the transparent electrode includes a step of applying a photosensitive agent to a glass substrate on which a transparent conductive film is deposited, a step of exposing the glass substrate on which the photosensitive agent is applied using the above-described exposure apparatus, and a glass substrate. The process of developing is included. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before.

DESCRIPTION OF SYMBOLS 10 Illuminating device 20 Original stage 30 Projection optical system 40 Interferometer 50 Stage 51 Main body base 52 Y stage 53 X stage 54 θZ stage 55 Z tilt mechanism 60 Support system 61 Support part 62 Air bearing 63 Pressurized magnet M Original W substrate

Claims (7)

A stage apparatus comprising: holding means for holding a substrate; and support means for supporting the holding means and driving the holding means in a push-up direction with respect to a surface opposite to the holding surface,
Bearing means provided on the support means, supplying gas between the opposite surface and the support means, and causing the holding means to float from the support means;
Detecting means for detecting a flow rate of gas supplied from the bearing means;
Control means for controlling the driving of the support means,
The control means controls driving of the support means so that a flow rate detected by the detection means falls within a predetermined flow rate range when the holding means is levitated by the bearing means. A stage device.   The control means includes a first control part for controlling the driving of the support means, a second control part for controlling a gas flow rate of the bearing means to float and seat the holding means, and the detected A control unit that generates a control signal for controlling the driving of the support means and transmits the control signal to the first control unit in order to set the flow rate of the gas within the range of the predetermined flow rate. The stage apparatus according to claim 1.   The stage apparatus according to claim 1 or 2, wherein the detection means detects after the floated holding means is seated.   The calculation unit transmits the control signal to the first control unit until the support unit that is detected by the detection unit to be out of the predetermined flow rate range is within the predetermined flow rate range. The stage apparatus according to claim 2 or 3, wherein feedback control is performed.   When the calculation unit determines that the flow rate detected by the detection unit is within the predetermined range by the feedback control, the calculation unit adjusts the displacement of the surface of the substrate in order to adjust the flatness of the substrate. 5. The measurement result data is received from a displacement sensor to be measured, a control signal for controlling the driving of the support means is calculated based on the measurement result data, and transmitted to the first control unit. Stage device. An exposure apparatus for projecting an original pattern onto a substrate placed on a stage via a projection optical system,
An exposure apparatus comprising the stage apparatus according to any one of claims 1 to 5.   7. A device manufacturing method comprising: exposing a substrate using the exposure apparatus according to claim 6; and developing the substrate.

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