JP2008052006A - Exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure apparatus capable of quickly correcting a frame due to a secular change and an installment condition. <P>SOLUTION: The exposure apparatus corrects by comparing a light receiving position of light receiving parts PDx and PDy with a stored light receiving position and discriminating that the frame 3 is deformed if they are different. The correction moves a second tapered part 2b of any one of height adjustment devices along a surface plate G, and raises or lowers a first tapered part 2a due to wedge action. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exposure apparatus suitable for printing a mask pattern on a substrate such as a liquid crystal substrate or a color filter for a liquid crystal display.

Due to the recent increase in size of semiconductor wafers and liquid crystal substrates, the size of manufacturing apparatuses is required. On the other hand, miniaturization and weight reduction of the apparatus are strongly demanded. An exposure apparatus such as Patent Document 1 is a precision component manufacturing apparatus that transfers a mask pattern to a liquid crystal substrate with a mask and a work facing each other with a gap of several tens to several hundreds of micrometers. In such a manufacturing apparatus, there is a problem that characteristics (positioning accuracy, flatness of a reference surface) of the apparatus change due to a change in the installation state of the apparatus. For this reason, it is necessary to assemble the device on a surface plate that is ideally supported at 3 points (actually 4 points) and does not deform due to the weight of the positioning system.
JP 2000-35676 A

  In particular, recently, it has become necessary to perform exposure processing using a substrate of several thousand mm or more as a work for a liquid crystal substrate. However, in order to configure the surface plate of such an exposure apparatus with three or four points, it is necessary to use a surface plate having a weight of several tens of tons or more. There is a problem that the surface plate takes time to install. Therefore, instead of using such a surface plate, by increasing the holding point of the surface plate to increase the flatness and lowering the required rigidity of the surface plate, it is possible to reduce the thickness of the surface plate or remove the structure (rib structure) It has been attempted to reduce the weight.

  However, in the exposure apparatus that holds the surface plate at multiple points, there is a problem that the flatness of the surface plate changes due to aging of the installation floor and parts that hold the surface plate against the installation floor. In particular, in the previous exposure apparatus, it is necessary to expose a mask having a size of 1000 mm or more and a liquid crystal substrate while maintaining the above-mentioned narrow gap, and a change in flatness of the surface plate is an important issue. However, it is difficult to correct the surface plate itself after being installed. In addition, in large exposure systems, assembly and checking may be performed before shipment, then disassembled and transported to the local site (semiconductor manufacturing factory), where they may be assembled locally. There is a case where the frame of the exposure apparatus may be deformed due to the difference from the surface plate of this, and how to deal with this is also a problem.

  An object of the present invention is to provide an exposure apparatus capable of quickly correcting a frame by a change with time or a change in installation conditions.

The exposure apparatus of the present invention is an exposure apparatus that exposes a mask pattern onto a substrate using exposure light.
A base installed on a surface plate,
A stage placed on the base and movably supporting the substrate;
A frame mounted on the base and holding a mask;
And a measuring device installed on the frame for measuring deformation of the frame.

  When the exposure apparatus is assembled on site, trial exposure can be performed after assembly and the deformation of the frame can be corrected accordingly. In addition, frame deformation due to changes over time can be corrected during regular maintenance, but both have the problem that several trial exposures are required after correction, which is troublesome.

  On the other hand, according to the present invention, since the measuring device for measuring the deformation of the frame is provided, when assembling the exposure apparatus at the site, the deformation can be appropriately corrected by measuring the deformation of the frame by the measuring device after assembling. Therefore, it is not necessary to perform trial exposure that requires a light source, an optical system, and the like, and the exposure apparatus can be installed quickly. Even if the frame is deformed due to deterioration over time, the amount of deformation can be obtained by checking the output signal of the measuring device at any time. Therefore, it is sufficient if the frame is corrected when it exceeds the allowable range, and maintenance is performed. Can be saved.

  The measurement apparatus includes a light emitting unit that emits measurement light and a light receiving unit that receives the measurement light, and the amount or the light receiving position of the measurement light received by the light receiving unit according to the deformation of the frame. It is preferable to change.

  It is preferable that the amount of measurement light received by the light receiving unit changes according to the displacement of the movable member disposed between the light emitting unit and the light receiving unit.

  It is preferable that the light receiving area of the light receiving part is larger than the cross-sectional area of the measurement light emitted from the light receiving part, because the relative deviation between the light emitting part and the light receiving part can be measured with high accuracy.

  It is preferable to output an alarm when the signal from the measuring device exceeds a predetermined value.

  It is preferable to have a correction device for correcting the deformation of the frame when the signal from the measurement device exceeds a predetermined value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the proximity exposure apparatus according to the first embodiment, and FIG. 2 is a view of the proximity exposure apparatus of FIG. 1 as viewed in the direction of arrow II.

  1 and 2, the base 1 is placed on the surface plate G via the height adjusting device 2. The height adjusting device 2 includes a first taper portion 2a attached to the lower surface of the base 1, and a second taper portion 2b movably mounted on the surface plate G. The first taper portion 2a The 2nd taper part 2b is installed in contact with each taper surface.

  A frame 3 is installed on the base 1. The frame 3 includes a leg portion 3a whose lower end is fixed to the edge of the base 1, and a top plate 3b attached to the upper end of the leg portion 3a. An opening is formed in the center of the top plate 3b, and a mask holder 4 holding a mask M is attached around the opening.

  On the upper surface of the base 1, four guide rails 5 are arranged in parallel and extend in the left-right direction (X-axis direction) in FIG. A slider 6 is movably provided along each guide rail 5. The slider 6 is attached to the lower surface of the X-axis table 7. An X-axis linear motor 8 is provided between the base 1 and the X-axis table 7 so that the X-axis table 7 can be driven in the X-axis direction with respect to the base 1.

  Four guide rails 9 are arranged on the upper surface of the X-axis table 7 so as to extend in parallel and in a direction perpendicular to the paper surface (Y-axis direction) in FIG. A slider 10 is movably provided along each guide rail 9. The slider 10 is attached to the lower surface of the substrate support portion 11. A Y-axis linear motor 12 is provided between the X-axis table 7 and the substrate support 11, and the substrate support 11 can be driven in the Y-axis direction with respect to the X-axis table 7. The substrate support unit 11 includes a substrate table 11a that supports a substrate W (see FIG. 6, not shown in FIGS. 1 and 2), and a Z-axis drive unit that drives the substrate table 11a in the vertical direction (Z-axis direction) in FIG. 11b.

  At the time of exposure, the substrate W is stepped with respect to the mask M in the two directions of the X-axis direction and the Y-axis direction, and the mask M and the substrate W are arranged close to each other and face each other. The pattern exposure pattern from the light source is exposed and transferred onto the substrate W by irradiating light from the light source toward the mask M from above in FIGS.

  Next, frame correction will be described. As shown in FIG. 1, a light emitting portion LDx that emits X-axis laser light (measurement light) in the X-axis direction and a light receiving position and a light receiving portion that receives the X-axis laser light, A light-receiving unit PDx that outputs a signal corresponding to the amount of received light is attached, and as shown in FIG. 2, a light-emitting unit LDy that emits Y-axis laser light (measurement light) in the Y-axis direction, and the Y-axis A light receiving unit PDy that receives laser light and outputs a signal corresponding to the light receiving position and the amount of light received is attached. The area of the light receiving surface of the light receiving unit PDx is larger than the cross-sectional area of the X-axis laser light, and the area of the light receiving surface of the light receiving unit PDy is larger in the height direction than the cross-sectional area of the Y-axis laser light. The light emitting portions LDx and LDy are preferably semiconductor lasers, and the light receiving portions PDx and PDy are preferably line sensors such as a CCD. As the light emitting unit and the light receiving unit, a sensor (LV [trade name] series) marketed by Keyence Corporation can be used. The light emitting units LDx and LDy and the light receiving units PDx and PDy constitute a measuring device.

  At the time of assembly check before shipment, the X-axis laser light emitted from the light emitting part LDx is received by the light receiving part PDx, the light receiving position is stored, and the Y axis laser light emitted from the light emitting part LDy is received by the light receiving part PDy. To store the light receiving position. After that, it is disassembled and transported to the site, and installed on the local surface plate G. After the assembly, the X-axis laser light emitted from the light emitting part LDx is received by the light receiving part PDx, and the Y axis laser light emitted from the light emitting part LDy is received by the light receiving part PDy. The light receiving positions of the light receiving parts PDx and PDy at this time are compared with the stored light receiving positions, and if they are different, it is determined that the frame 3 is deformed, and the frame is corrected so that the light receiving positions match. Such correction can be performed by moving any of the second tapered portions 2b of the height adjusting device 2 along the surface plate G, and raising or lowering the first tapered portion 2a by the action of the wedge. The second taper portion 2a may be moved by an actuator or the like. According to the present embodiment, it is possible to ensure an appropriate exposure state in the exposure apparatus even though trial exposure that requires time before and after frame correction is unnecessary.

  On the other hand, when the proximity exposure apparatus is used for a long time, the frame 3 may be deformed due to a change with time. With respect to this, the X-axis laser light emitted from the light emitting part LDx in the initial state is received by the light receiving part PDx, the light receiving position is stored, and the Y axis laser light emitted from the light emitting part LDy is received by the light receiving part PDy. If the light receiving position is stored, the frame correction is performed by comparing the light receiving positions of the light receiving portions PDx and PDy with the stored light receiving positions at regular or regular intervals and issuing an alarm if they differ by more than a predetermined position. The optimal timing can be ensured.

  FIG. 3 is a schematic block diagram of an exposure apparatus according to another embodiment. In the present embodiment, the base 1 is supported at the four corners via the four vibration isolation tables 20 with respect to the surface plate G. Further, the output signals of the light receiving portions PDx and PDy are transmitted to the exposure apparatus controller CTU via the amplifier AP, and further, the control signal from the exposure apparatus controller CTU is transmitted to the vibration isolation table driver DR, and the vibration isolation is performed accordingly. The table driver DR raises or lowers each vibration isolation table 20 independently. Note that the vibration isolation table 20 as a correction device refers to a device that displaces the base 1 with respect to the surface plate G using a piezo element or the like, and is described in detail in, for example, Japanese Patent Application Laid-Open No. 2001-50334.

  According to the present embodiment, the exposure apparatus controller CTU detects the deformation of the frame 3 in accordance with the output signals of the light receiving units PDx and PDy, and the vibration isolation table driver DR automatically sets the vibration isolation table 20 in response thereto. Since it is displaced, there is no need for maintenance, and stable exposure can be realized over a long period of time.

  By the way, the light emitting units LDx and LDy and the light receiving units PDx and PDy can be used not only as detection of frame deformation but also as a position detection sensor of a movable member. For example, as shown in FIG. 4, when the movable member MM is placed between the light emitting part LDx and the light receiving part PDx, the laser light emitted from the light emitting part LDx at the reference position shown in FIG. It is assumed that 50% of L is blocked by the movable member MM. Here, as shown in FIG. 4B, when the movable member MM moves relatively downward, the amount of light blocked by the movable member MM becomes less than 50%. On the other hand, when the movable member MM moves relatively upward, the movable member MM moves. The amount of light intercepted by the MM exceeds 50%. Since the amount of light blocked by the movable member MM can be detected by the light receiving unit PDx, the movement amount (displacement amount) of the movable member MM in the Z-axis direction can be detected by a signal from the light receiving unit PDx.

  FIG. 5 is a cross-sectional view similar to FIG. 1 according to a modification of the present embodiment to which this is applied. In FIG. 5, the substrate table 11a of the exposure apparatus is in a substrate exchange state, that is, in a lowered state, and the substrate W is placed on the robot hand RB of the external transfer apparatus CA, and the substrate W is received by the substrate table 11a from here. Shows the state just before being passed. Here, if the position of the robot hand RB is too high, it may interfere with the mask M, and conversely if it is too low, it may interfere with the substrate support portion 11. Therefore, when the robot hand RB as a movable member passes between the light emitting unit LDx and the light receiving unit PDx attached to the leg 3a, the Z axis direction of the robot hand RB from the position where the laser beam of the light emitting unit LDx is blocked. When the position in the (height direction) is determined and it exceeds a predetermined position, the operation of the robot hand RB is urgently locked to avoid interference, thereby enabling the safe transfer and unloading of the substrate W. .

  FIG. 6 is a cross-sectional view similar to FIG. 1 according to another application example of the present embodiment. In FIG. 6, the board | substrate support part 11 comprises a movable member. That is, during the proximity exposure of the substrate W, the position of the substrate W in the Z-axis direction must be accurately controlled with respect to the mask M, but the control signal to the Z-axis drive unit 11b of the substrate support unit 11 is incorrect. Then, interference with the mask M may be caused and the expensive mask M may be damaged. According to this application example, the position in the Z-axis direction (height direction) of the substrate support unit 11 is determined from the position where the laser beam of the light emitting unit LDx is blocked. Take measures such as emergency locking.

  The present invention has been described above with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and can of course be changed or improved within the scope of the invention. For example, by arranging the mask M and the substrate W between the light emitting part LDx and the light receiving part PDx, the thickness can be detected, and it can be checked beforehand that the specification is correct. In particular, since the flatness and inclination of the support surface of the substrate table 11a are generally controlled with high accuracy with respect to the plate thickness of the substrate, it is suitable for measuring the plate thickness. In addition, the deformation of the frame not only directly detects the measurement light from the light emitting parts LDx and LDy by the light receiving parts PDx and PDy, but also blocks the measurement light with a shielding plate arranged on the base 1 or mounts it on the base 1. Detection can also be performed by reflecting the measurement light with a reflecting mirror. Furthermore, the present invention can be applied not only to a proximity exposure apparatus but also to a semiconductor exposure apparatus, and further to various manufacturing apparatuses that are equipped with an inspection microscope and detect the mutual height of frames. The measurement apparatus may be a reflection type instead of a transmission type, and may use two-dimensional image recognition.

1 is a cross-sectional view of a proximity exposure apparatus according to a first embodiment. It is the figure which looked at the proximity exposure apparatus of FIG. 1 in the direction of arrow II. It is a schematic block diagram of the exposure apparatus concerning another embodiment. It is a figure which shows the relationship between a light emission part and a light-receiving part. It is sectional drawing similar to FIG. 1 concerning the application example of this Embodiment. It is sectional drawing similar to FIG. 1 concerning the application example of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Height adjustment apparatus 2a 1st taper part 2b 2nd taper part 3 Frame 3a Leg part 3b Top plate 4 Mask holder 5 Guide rail 6 Slider 7 X-axis table 8 X-axis linear motor 9 Guide rail 10 Slider 11 Substrate support Unit 11a Substrate table 11b Z-axis drive unit 12 Y-axis linear motor AP Amplifier CA Transport device CTU Exposure device controller DR Anti-vibration table driver G Surface plate L Laser light LDx Light-emitting portion LDy Light-emitting portion M Mask MM Movable member PDx Light-receiving portion PDy Light-receiving RB Robot Hand W Substrate

Claims (6)

In an exposure apparatus that exposes a mask pattern onto a substrate using exposure light,
A base installed on a surface plate,
A stage placed on the base and movably supporting the substrate;
A frame mounted on the base and holding a mask;
An exposure apparatus, comprising: a measuring device installed on the frame and measuring deformation of the frame.   The measurement apparatus includes a light emitting unit that emits measurement light and a light receiving unit that receives the measurement light, and the amount or the light receiving position of the measurement light received by the light receiving unit according to the deformation of the frame. The exposure apparatus according to claim 1, wherein the exposure apparatus changes.   The exposure apparatus according to claim 2, wherein an amount of measurement light received by the light receiving unit is changed according to a displacement of a movable member disposed between the light emitting unit and the light receiving unit.   The exposure apparatus according to claim 2, wherein a light receiving area of the light receiving unit is larger than a cross-sectional area of measurement light emitted from the light receiving unit.   5. The exposure apparatus according to claim 1, wherein an alarm is output when a signal from the measurement apparatus exceeds a predetermined value. 6. The exposure apparatus according to claim 1, further comprising a correction device that corrects deformation of the frame when a signal from the measurement device exceeds a predetermined value.

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