JP2006337838A - Exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure apparatus capable of detecting presence or absence of an abnormality on a work to lower adsorptivity without significant cost increase. <P>SOLUTION: The exposure apparatus in which exposure is conducted by sucking the work W to be exposed on a work stage 12, is equipped with: a first vacuum sensor 20 taking on an ON state when suction pressure of a work suction hole 16 is over -30 kPa, and taking on an OFF state when that is under -30 kPa; a second vacuum sensor 21 taking on the ON state when the suction pressure of the work suction hole 16 is over 0 kPa, and taking on the OFF state when that is under 0 kPa; and an abnormality detecting means 22 detecting presence or absence of the abnormality on the work W based on the ON/OFF states of the vacuum sensors 20, 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exposure apparatus used in, for example, a manufacturing process of a liquid crystal display device.

  As an exposure apparatus used in a manufacturing process of a liquid crystal display device or the like, for example, an exposure apparatus that exposes a work to be exposed close to a photomask (hereinafter referred to as “proximity exposure apparatus”) is known (Patent Document 1). reference). As shown in FIG. 4, this proximity exposure apparatus includes a mask stage 12 that supports a photomask M via a mask holder 11, and a work stage 13 is provided below the mask stage 12. In addition, a work stage elevating mechanism 14 for moving the work stage 13 up and down is provided, and a work stage feeding mechanism 15 for driving the work stage 13 in the X and Y directions in the drawing is provided.

  A plurality of workpiece suction holes 16 (see FIG. 5) are provided on the upper surface of the workpiece stage 13 in order to attract the workpiece W onto the workpiece stage 13 and perform proximity exposure. These work suction holes 16 communicate with a vacuum pump 18 via a suction line 17, and the suction line 17 has a vacuum for detecting whether or not the work W is adsorbed on the work stage 13. A sensor 19 is provided.

The photomask M is also held on the lower surface of the mask stage 12 by a suction mechanism having a suction hole, a suction conduit, and a vacuum pump.
In such an exposure apparatus, proximity exposure can be performed with the work to be exposed and the photomask adsorbed to the work stage or the mask stage. Therefore, the work stage is moved by the work stage lifting mechanism and the work stage feed mechanism. There is an advantage that the work and the photomask can be prevented from being displaced at times.
JP 2002-365810 A

  However, for example, if there is an abnormality that reduces the suction force (for example, damage such as chipping or foreign matter adhesion) on the workpiece, the pressure value at which the suction pressure of the workpiece suction hole can be considered to be temporarily sucked safely ( For example, the negative pressure exceeds -30 kPa (gauge pressure), but the value becomes lower than -30 kPa as time passes (that is, the negative pressure becomes smaller and approaches 0 kPa as the gauge pressure), and the workpiece is likely to be displaced. . In order to prevent this, if a sufficiently large value (for example, −90 kPa) corresponding to a normal stable use state (steady state) is set as a reference value for determining that there is an abnormality, a negative value that does not actually cause the workpiece position shift is negative. Despite being adsorbed by pressure, it may be determined as “abnormal” or it may take time until it is determined as “normal”. In addition, an optical sensor is used to detect whether or not an abnormality that reduces the suction force is present in the workpiece. For example, the lower surface of the workpiece attracted on the workpiece stage is imaged with a CCD camera or the like to determine whether or not there is an abnormality. However, it is not only difficult to perform reliable detection with such a method, but there is also a problem that the cost is significantly increased.

The same applies to a photomask.
The present invention has been made paying attention to such a problem, and it is possible to detect whether or not an abnormality that lowers the attractive force exists in a workpiece or a photomask without incurring a significant increase in cost. An object of the present invention is to provide an exposure apparatus that can perform this.

  In order to achieve the above object, the present invention provides an exposure apparatus that performs exposure by sucking a work or photomask to be exposed to a suction surface having a plurality of suction holes, and the suction pressure of the suction holes is higher than a steady state. A first vacuum sensor that is turned on when the pressure is equal to or greater than a small first reference suction pressure and that is turned off when the pressure is lower than the first reference suction pressure, and a second reference suction pressure that is smaller than the first reference suction pressure The second vacuum sensor is turned on when exceeding the second reference suction pressure and turned off when the second reference suction pressure is lowered, and the suction is based on the ON / OFF states of the first vacuum sensor and the second vacuum sensor. And an abnormality detecting means for detecting whether or not an abnormality that reduces the force is present in the workpiece or the photomask.

  According to the exposure apparatus of the present invention, it is possible to detect whether or not there is an abnormality that reduces the attractive force in the workpiece or the photomask by the abnormality detection means. Compared with the case where the presence / absence of an abnormality is detected by imaging, it is possible to detect whether or not an abnormality that reduces the suction force is present in the work or the photomask without causing a significant increase in cost.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3, but the same parts as those shown in FIGS. 4 and 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. To do.
FIG. 1 is a view showing a main part of a proximity exposure apparatus according to an embodiment of the present invention. As shown in FIG. 1, the proximity exposure apparatus according to this embodiment includes a first vacuum sensor 20, A second vacuum sensor 21 and an abnormality detection device 22 are provided.

The first vacuum sensor 20 is provided in the suction line 17, and as shown in FIG. 2, when the suction pressure of the workpiece suction hole 16 exceeds -30 kPa, which is set as the first reference suction pressure, a signal output is generated. The signal output is switched from the ON state to the OFF state when it is switched from the OFF state to the ON state and falls below −30 kPa.
Under the conditions of the present embodiment, the minimum suction pressure that can safely attract the workpiece W was −30 kPa, so this value was taken as the first reference suction pressure.

  Similar to the first vacuum sensor 20, the second vacuum sensor 21 is provided in the suction line 17. As shown in FIG. 2, the vacuum sensor 21 outputs a signal when the suction pressure of the workpiece suction hole 16 exceeds 0 kPa (atmospheric pressure) set as the second reference suction pressure (becomes negative pressure). The signal output is switched from the ON state to the OFF state when it is switched from the OFF state to the ON state and becomes 0 kPa.

As the second reference suction pressure, it is sufficient that the difference from the first reference suction pressure is a value sufficient to prevent malfunction due to, for example, chattering.
The abnormality detection device 22 is configured to detect whether or not there is an abnormality in the workpiece that reduces the suction force based on the ON / OFF state of the first vacuum sensor 20 and the second vacuum sensor 21. The detection result of the abnormality detection device 22 is displayed on a display device (not shown).

  The determination unit configured by appropriate software or hardware included in the abnormality detection device 22 determines whether or not there is an abnormality, for example, as follows. First, after the suction of the workpiece W exceeds 0 kPa, and once the vacuum sensor 21 is turned on, the vacuum sensor 20 is turned on (that is, reaches −30 kPa) regardless of the state of the vacuum sensor 21. Determined to be normal. However, if it does not reach −30 kPa within a predetermined time, it is determined as abnormal. Next, once the vacuum sensor 20 is turned on, until the second predetermined time elapses, it is normal unless the second vacuum sensor 21 is turned off regardless of the state of the vacuum sensor 20. judge. Thereafter, the determination is made based on the state of the vacuum sensor 20. The second determination time is a time required to reach the suction pressure at which the vacuum sensor 20 does not have a possibility of being turned off regardless of the abnormality of the work due to chattering or the like (obtained in advance by experimenting with a normal work) And

  In such a configuration, when there is no workpiece W on the workpiece stage 12, the suction pressure of the workpiece suction hole 16 does not become a negative pressure exceeding 0 kPa. Therefore, as shown in FIG. Both the sensor 20 and the second vacuum sensor 21 have their signal outputs “OFF”. Further, when there is no abnormality in the workpiece W that reduces the suction force, the suction pressure of the workpiece suction hole 16 becomes a negative pressure exceeding −30 kPa, and therefore, as shown in FIG. The signal output of the second vacuum sensor 21 is both “ON”.

  On the other hand, if there is an abnormality in the workpiece that reduces the suction force, the suction pressure of the workpiece suction hole 16 temporarily becomes a negative pressure exceeding -30 kPa, and although it does not decrease to 0 kPa over time, it is stable. As a result of the experiment, it has been found that there may be a negative pressure lower than −30 kPa, which is not an adsorption state. In such a case, in the present embodiment, as shown in FIG. 3, only the first vacuum sensor 20 is turned “OFF”, so that the first vacuum sensor 20 and the second vacuum sensor 21 are turned on. It becomes possible for the abnormality detection device 22 to detect whether or not there is an abnormality in the workpiece that reduces the suction force based on the / OFF state. Therefore, in the above-described embodiment, as compared with the case where the lower surface of the workpiece is imaged with a CCD camera or the like and the presence or absence of the abnormality is detected, it is easy and sure whether or not there is an abnormality in the workpiece that reduces the suction force. Moreover, it can be detected without causing a significant increase in cost.

  By the way, it is conceivable to use one vacuum sensor and turn it ON when the pressure is higher than the first reference suction pressure and then turn OFF when the pressure drops to the second reference suction pressure. Even in this way, chattering and misunderstandings can be avoided. However, in the case where there is an abnormality, it is not possible to detect a case where the temperature once drops to −30 kPa or more and then falls to 0 kPa or more and less than −30 kPa.

  On the other hand, according to the present embodiment, as described above, such an abnormality can also be detected. In the present embodiment, the case where the object to be adsorbed is a workpiece has been described. However, the present invention can also be applied to the case where the object to be adsorbed is a photomask. In the present embodiment, the first reference suction pressure is set to −30 kPa, and the second reference suction pressure smaller than this is set to 0 kPa. However, the first reference suction pressure is appropriately determined depending on the type of the object to be adsorbed, the use conditions, and the like.

It is a figure which shows the principal part of the proximity exposure apparatus which concerns on one Embodiment of this invention. It is a figure which shows the signal output waveform of the vacuum sensor shown in FIG. It is explanatory drawing for demonstrating the abnormality detection method of the abnormality detection apparatus shown in FIG. It is a figure which shows schematic structure of a proximity exposure apparatus. It is a figure which shows the work stage of a proximity exposure apparatus.

Explanation of symbols

W Work M Photomask 11 Mask holder 12 Mask stage 13 Work stage 14 Work stage lifting mechanism 15 Work stage feed mechanism 16 Work suction hole 17 Suction line 18 Vacuum pump 20 First vacuum sensor 21 Second vacuum sensor 22 Abnormality detection apparatus

Claims (1)

In an exposure apparatus that performs exposure by sucking a work or photomask to be exposed to a suction surface having a plurality of suction holes,
A first vacuum sensor that is turned on when the suction pressure of the suction hole is equal to or higher than a first reference suction pressure that is smaller than a steady state, and that is turned off when the suction pressure is lower than the first reference suction pressure; A second vacuum sensor that is turned on when a second reference suction pressure smaller than the suction pressure is exceeded and is turned off when the second reference suction pressure is lowered; the first vacuum sensor; and the second vacuum sensor An exposure apparatus comprising: an abnormality detection unit configured to detect whether an abnormality that reduces the suction force based on an ON / OFF state of the sensor exists in the workpiece or the photomask.

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