JP2006093604A - Proximity exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a mask from being shifted even when a speed of a substrate released from the mask after exposure by increasing a mask holding force, thereby increasing a throughput. <P>SOLUTION: A transparent glass plate 40 is fixedly located within a vacuum suction frame 26 for vacuum sucking a mask M, and air between the glass plate 40 and the mask M is vacuum sucked, so that the mask M is vacuum sucked by the frame 26 and the glass plate 40. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a proximity exposure apparatus suitable for proximity exposure transfer of a mask pattern onto a substrate such as a large flat panel display such as a liquid crystal display or a plasma display.

  In the proximity exposure, referring to FIG. 4, a translucent substrate (material to be exposed) coated with a photosensitive agent on the surface is held on the substrate stage of the proximity exposure apparatus, and the substrate is held on the mask holding frame of the mask stage. The gap between the two is made several tens of μm to several hundred μm, for example, and the exposure light is irradiated toward the mask by the irradiation device from the side away from the substrate of the mask. As a result, the pattern drawn on the mask is transferred onto the substrate by exposure.

By the way, in proximity exposure, there is a method in which the mask is made the same size as the substrate and is exposed in a lump. However, in such a method, when the mask pattern is exposed and transferred onto a large substrate, the mask becomes large and the mask is exposed. This causes problems in terms of the influence on the pattern accuracy due to the bending of the pattern and the cost.
For these reasons, conventionally, when a mask pattern is exposed and transferred onto a large substrate, a mask smaller than the substrate is used, and the substrate stage is moved stepwise relative to the mask, for example, in the Y-axis direction. The so-called stepwise proximity exposure system that irradiates the pattern exposure light in a state in which the mask is placed close to the substrate at each step, thereby exposing and transferring a plurality of patterns drawn on the mask onto the substrate. May be used.

Specifically, first, for example, the orientation of the mask is adjusted through the mask holding frame so that the alignment mark on the substrate stage side and the alignment mark on the mask side are aligned, and the position of the substrate stage and the mask is aligned. The posture (position) of the mask is stored in a storage device or the like.
Next, the substrate mounted on the substrate stage is brought close to the mask, and light for pattern exposure is irradiated from the irradiation means toward the mask with the substrate and the mask interposed through a minute gap, and the first mask pattern is formed on the substrate. Transfer to exposure.

Next, the substrate is separated from the mask, and in this state, the substrate stage is sent by one step amount relative to the mask. At this time, for example, a feed error of the substrate stage occurs due to the accuracy of a linear guide or the like. Therefore, if the next step exposure is performed as it is, the relative position between the exposure pattern of the next step formed on the substrate and the exposure pattern of the first step is shifted.
For this reason, before performing exposure in the next step, an optical measurement sensor such as a laser interferometer detects a feed error (positional deviation) of the substrate stage, and the detection result and initial posture information of the mask stored in the storage device. Based on the above, the orientation of the mask is corrected through the mask holding frame to align the position of the substrate and the mask, and the exposure of the next step is performed in this state, so that the relative position of each exposure pattern on the substrate So that no shift occurs.

In the conventional proximity exposure apparatus, referring to FIG. 5, if the speed of separating the substrate from the mask after the exposure transfer is increased to increase the throughput of the apparatus, the space between the substrate and the mask is increased. A large negative pressure is generated instantaneously due to the fluid resistance to which air suddenly flows into the narrow gap, and if this negative pressure is larger than the suction force of the mask by the vacuum suction groove of the vacuum suction frame, the mask will be against the vacuum suction frame. It may shift. For this reason, the substrate must be slowly separated from the mask after exposure, which causes a reduction in the throughput of the apparatus.
The present invention has been made to solve such inconveniences, and by improving the holding power of the mask, it is possible to prevent the mask from shifting even if the speed of separating the substrate from the mask is increased after exposure. Therefore, an object of the present invention is to provide a proximity exposure apparatus capable of improving throughput.

To achieve the above object, the invention according to claim 1 is directed to a substrate stage for holding a substrate as an exposed material, a mask having a pattern to be exposed, and a mask for holding the mask via a vacuum suction frame. Pattern exposure light is directed to the mask to expose and transfer the mask pattern onto the substrate with a mask stage that supports the holding frame in an adjustable manner and the substrate and the mask through a minute gap. In a proximity exposure apparatus provided with irradiation means for irradiating
A transparent plate member is fixedly arranged in the frame of the vacuum suction frame, and the mask is vacuum-sucked by the vacuum suction frame and the transparent plate member by vacuum suction of air between the transparent plate member and the mask. It is characterized by doing.
The invention according to claim 2 is characterized in that, in claim 1, vacuum suction grooves provided in the vacuum suction frame are opened on the mask side surface and the side surface of the transparent plate member.

According to the present invention, since the mask is vacuum-sucked by the vacuum suction frame and the transparent plate member fixedly arranged in the frame of the vacuum suction frame, the holding power of the mask can be improved. Even if the speed at which the substrate is separated from the mask later is increased, the mask can be prevented from shifting, and the throughput of the apparatus can be improved.
Further, since the mask is sucked and held along the transparent plate member, even when a large mask is held, it is possible to prevent the mask from being bent due to its own weight, thereby improving the flatness of the mask and printing. The dimensional accuracy of the pattern can be improved.

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. 1 is a partially broken explanatory view for explaining a proximity exposure apparatus which is an example of an embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is viewed from the direction of arrow A in FIG. It is a figure.
As shown in FIG. 1, a proximity exposure apparatus as an example of an embodiment of the present invention uses a mask M smaller than a substrate W as a material to be exposed, holds the mask M on a mask stage 1, and holds the substrate W on the substrate W. The substrate stage 2 is held in this state, and in this state, the substrate stage 2 is moved stepwise with respect to the mask M in the two axial directions of the X-axis direction and the Y-axis direction, and the mask M and the substrate W are opposed to each other in close proximity. In the arranged state, a plurality of patterns of the mask M are exposed and transferred onto the substrate W by irradiating light for pattern exposure from the irradiation means 3 toward the mask M through a transparent plate glass 40 described later. Is.

  In FIG. 1, reference numeral 4 denotes an apparatus base 4. An X-axis stage feed mechanism 5 for moving the substrate stage 2 stepwise in the X-axis direction is installed on the apparatus base 4. A Y-axis stage feed mechanism 6 for moving the substrate stage 2 stepwise in the Y-axis direction is installed on the axis feed table 5a, and the substrate stage 2 is installed on the Y-axis feed table 6a of the Y-axis stage feed mechanism 6. Has been. A substrate W is held on the upper surface of the substrate stage 2 in a state of being vacuumed by a work chuck or the like.

  Between the Y-axis stage feed mechanism 6 and the substrate stage 2, there is a vertical coarse motion device 7 having a relatively coarse positioning resolution that performs a simple vertical movement of the substrate stage 2 but a large movement stroke and movement speed, and a vertical coarse motion A vertical fine movement device 8 that can be positioned with higher resolution than the apparatus 7 and finely adjusts the gap between the opposing surfaces of the mask M and the substrate W to a predetermined amount by finely moving the substrate stage 2 up and down is installed.

  The vertical coarse movement device 7 moves the substrate stage 2 up and down with respect to the fine movement stage 6b by an appropriate drive mechanism provided on the fine movement stage 6b described later. Reference numeral 14a denotes a coarse movement shaft fixed at four positions on the bottom surface of the substrate stage 2, which engages with a linear motion bearing 14 fixed to the fine movement stage 6b and is guided in the vertical direction with respect to the fine movement stage 6b. Note that it is desirable that the vertical coarse motion device 7 has high repeated positioning accuracy even if the resolution is low.

  The vertical fine movement device 8 includes a fixed base 9 fixed to the Y-axis feed base 6a, and a linear guide guide rail 10 attached to the fixed base 9 with its inner end inclined obliquely downward. A ball screw nut (not shown) is connected to a slide body 12 that reciprocates along the guide rail 10 via a slider 11 straddling the guide rail 10. Is in contact with the flange 12a fixed to the fine movement stage 6b so as to be slidable in the horizontal direction.

Further, the flange 12a and the fixing base 9 are connected by a leaf spring 15 as shown in FIG. The leaf spring 15 has three tongue pieces 16 a, 16 b and 16 c, a central tongue piece 16 b is fixed to the flange 12 a, and both tongue pieces 16 a and 16 c are fixed to the fixing base 9.
Therefore, the flange 12a is restricted from moving in the horizontal plane (in the XY plane), and only fine movement in the vertical direction and a slight change in inclination are allowed. In addition, you may make it fix the tongue piece 16b of a center to the fixing stand 9, and the tongue pieces 16a and 16c of both sides to the flange 12a.

Then, when the screw shaft of the ball screw is rotationally driven by the motor 17 attached to the fixed base 9, the nut, the slider 11 and the slide body 12 are integrally moved along the guide rail 10 in an oblique direction. The flange 12a is finely moved up and down. At this time, the horizontal displacement of the flange 12 a is restricted by the action of the leaf spring 15.
The vertical fine movement device 8 is installed on one end side (left end side in FIG. 1) in the Y-axis direction of the Z-axis feed base 6a and two on the other end side, and a total of three are installed and controlled independently. It is like that. Thereby, the vertical fine movement device 8 finely adjusts the height of the flanges 12a at the three locations independently based on the measurement results of the gap amounts between the mask M and the substrate W at a plurality of locations by the gap sensor 31 described later. Since the height and inclination of the stage 2 can be finely adjusted, the gap between the mask M and the substrate W can be set to a target value with good parallelism.

On the Y-axis feed base 6a, a bar mirror 19 facing the Y-axis laser interferometer 18 that detects the position of the substrate stage 2 in the Y direction, and an X-axis laser that detects the position of the substrate stage 2 in the X-axis direction. A bar mirror (both not shown) facing the interferometer is installed.
The bar mirror 19 facing the Y-axis laser interferometer 18 extends along the X-axis direction on one side of the Y-axis feed base 6a, and the bar mirror facing the X-axis laser interferometer is on one end side of the Y-axis feed base 6a. It extends along the Y-axis direction.

The Y-axis laser interferometer and the X-axis laser interferometer are always arranged so as to face the corresponding bar mirrors and supported by the apparatus base 4. Two Y-axis laser interferometers 18 are installed apart from each other in the X-axis direction.
The two Y-axis laser interferometers 18 detect the position of the Y-axis feed base 6a and then the substrate stage 2 in the Y-axis direction and the yawing error via the bar mirror 19.

The X-axis laser interferometer detects the position of the X-axis feed base 5a and then the substrate stage 2 in the X-axis direction via the opposing bar mirror.
Two Y-axis direction position data and X-axis direction position data detection signals obtained during step feed are output to the control device, and the control device outputs this detection signal (actual position data) and commanded position data (to be positioned) A correction amount is calculated on the basis of the difference from the position data), and the calculation result is output to a driving circuit of a mask position adjusting means (and vertical fine movement device 8 as necessary), which will be described later. Accordingly, the mask position adjusting means and the like are controlled to correct the positional deviation and yawing error in the X-axis direction and the Y-axis direction, and the mask M is aligned so as to correctly face the position to be exposed on the substrate W. The control device is also used for gap adjustment and the like which will be described later.

The X-axis laser interferometer, the Y-axis laser interferometer, and the like are mainly used for exposure (first layer exposure) to the substrate W on which no pattern is formed yet. In the case of an exposure apparatus for exposure of the second and subsequent layers on the exposed substrate W, these may be omitted or used with an alignment camera.
The mask stage 1 can be moved in the X, Y, and θ directions (in the X, Y plane) by being inserted into a mask frame 24 formed of a substantially rectangular frame and a central opening of the mask frame 24 through a gap. The mask frame 24 is held in a fixed position above the substrate stage 2 by a support column 4 a protruding from the apparatus base 4.

As shown in FIGS. 1 and 2, a vacuum suction frame 26 is provided on the lower surface side of the central opening of the mask holding frame 25 along the entire circumference of the opening. A vacuum suction groove 26 a is provided on the lower surface of the frame 26.
Here, in this embodiment, a transparent plate glass (transparent plate member) 40 is disposed in substantially the entire area of the vacuum suction frame 26 and the upper flange 41 of the transparent plate glass 40 is supported on the upper surface of the vacuum suction frame 26. At the same time, the vacuum suction groove 26a is opened on the upper surface of the mask M on which the pattern to be exposed is drawn and the side surface of the transparent plate glass 40.

  The air in the vacuum suction groove 26a and the air between the lower surface of the transparent plate glass 40 and the upper surface of the mask M are evacuated to hold the mask M by vacuum suction with the vacuum suction frame 26 and the transparent plate glass 40. Like to do. In addition, it is preferable that the thickness of the transparent plate glass 40 is set to a dimension that can be maximized for design convenience, material convenience, and the like. At least sufficiently thicker than the thickness of the mask M.

  Further, above the transparent plate glass 40, a gap sensor 31 as a means for measuring the gap between the opposing surfaces of the mask M and the substrate W, and an alignment mark (not shown) provided in the exposure region of the mask M, As means for imaging an alignment mark (not shown: used for alignment of the second and subsequent layers) provided on the substrate W side or an alignment mark (not shown) provided on the substrate stage 2 on the substrate W side. The alignment cameras 30 are movably arranged.

  The gap sensors 31 are arranged at two locations in the Y-axis direction at two locations on the inner side of the two sides along the Y-axis direction of the flange 26, for a total of four locations. The measurement results of these four gap sensors 31 The amount of parallelism deviation between the opposing surfaces of the mask M and the substrate W can be detected by performing arithmetic processing with a control device (not shown) based on the above, and the above-described vertical fine movement device 8 described above according to this detected deviation amount. Is controlled to ensure the parallelism between the opposing surfaces of the mask M and the substrate W.

  The alignment cameras 30 are arranged in two locations, one in each of the upper center of the two sides along the X-axis direction of the flange 26, and approximately in the center of the X-axis direction. On the basis of this, the amount of plane deviation between the mask M and the substrate W can be detected by performing arithmetic processing with a control device (not shown), and the mask position adjusting means sets the mask holding frame 25 to X, X according to this detected plane deviation amount. The direction of the mask M held by the mask holding frame 25 with respect to the substrate W is adjusted by moving in the Y and θ directions.

  The mask position adjusting means is spaced apart from each other in the X-axis direction on one side along the X-axis direction of the mask holding frame 25 and an X-axis direction driving device (not shown) attached to one side along the Y-axis direction of the mask frame 24. And two Y-axis direction drive devices 29 (only one is shown) attached to the X-axis direction drive device to adjust the mask holding frame 25 in the X-axis direction. The drive device 29 adjusts the mask holding frame 25 in the Y-axis direction and the θ-axis direction (oscillation around the Z-axis). In FIG. 1, reference numeral 28 denotes a masking aperture mechanism having a light shielding blade that limits the exposure range by shielding exposure light in an arbitrary range on the mask M held by the mask holding frame 25 as necessary. .

  In order to perform step exposure in the Y-axis direction, for example, using the proximity exposure apparatus having the above-described configuration, first, the alignment mark on the substrate stage 2 imaged by the alignment camera 30 and the mask M held on the mask holding frame 25 are displayed. The mask position adjustment means adjusts the orientation of the mask M by moving the mask holding frame 25 in a predetermined direction in accordance with the amount of deviation from the alignment mark provided in the exposure region, thereby setting the initial position of the mask M with respect to the substrate stage 2. In addition, the posture (position) of the mask M at that time is stored in a storage area of a control device (not shown).

  Next, the substrate W is mounted and held on the substrate stage 2, and in this state, the substrate stage 2 is raised by the vertical coarse motion device 7 and the vertical fine motion device 8, and the gap between the opposing surfaces of the mask M and the substrate W is increased. By finely adjusting to a predetermined amount and irradiating light for pattern exposure from the irradiation means 3 to the mask M through the transparent plate glass 40 with the substrate W and the mask M through a minute gap, The mask pattern is exposed and transferred to the substrate W.

  Next, the substrate stage 2 is lowered by the vertical coarse motion device 7 or the vertical fine motion device 8 to separate the substrate W from the mask M, and in this state, the substrate stage 2 is moved relative to the mask M by the Y axis stage feed mechanism 6. Send one step amount in the direction. At this time, conventionally, when the speed at which the substrate W is separated from the mask M is increased to increase the throughput of the apparatus, the fluid resistance in which air suddenly flows into the narrow gap between the substrate W and the mask M is obtained. Due to this, a large negative pressure is instantaneously generated and the mask M may be displaced by this negative pressure. Therefore, the substrate W is slowly separated from the mask M after exposure, and the throughput of the apparatus is reduced. It was the cause.

  However, in this embodiment, as described above, the mask M is vacuum-sucked and held by the transparent plate glass 40 and the vacuum suction frame 26 that are fixedly arranged in substantially the entire area of the vacuum suction frame 26. Further, the holding force of the mask M is greatly improved as compared with the conventional case, and it is possible to prevent the mask M from shifting even if the speed at which the substrate W is separated from the mask M after the exposure is increased.

  Then, after the substrate stage 2 is fed by one step amount in the Y-axis direction with respect to the mask M by the Y-axis stage feed mechanism 6, the step feed error of the substrate stage 2 by the X-axis laser interferometer and the Y-axis laser interferometer 18. The correction control means (not shown) responds to the step feed error based on the detection signal (position error and yawing error in the X-axis direction and Y-axis direction) and the initial posture information of the mask M stored in the storage area. By calculating the correction amount of the orientation of the mask M and outputting the calculation result to the drive circuit of the mask position adjustment means (and the vertical fine movement device 8 as necessary), the mask position adjustment means according to each correction amount Are controlled to adjust the orientation of the mask M through the mask holding frame 25, so that, in the next step, before the first exposure pattern is transferred to the substrate W, the substrate W and the mask M are aligned. Align the location, for light exposure for the next step eyes in this state.

  As described above, in this embodiment, since the mask M is vacuum-sucked by the vacuum suction frame 26 and the transparent plate glass 40 fixedly arranged in substantially the entire area of the vacuum suction frame 26, the holding force of the mask M Can be significantly improved compared to the prior art, whereby the mask M can be prevented from shifting even if the speed at which the substrate W is separated from the mask M after exposure is increased, thereby improving the throughput of the apparatus. be able to.

Further, since the mask M is sucked and held along the lower surface of the transparent plate glass 40, even when the large mask M is held, it is possible to prevent the mask M from being bent due to its own weight. The degree can be improved and the dimensional accuracy of the printing pattern can be improved.
Further, since the vacuum suction groove 26a is opened on the upper surface of the mask M and the side surface of the transparent plate glass 40, the transparent plate glass 40 is directly vacuum-sucked together with the mask M by the vacuum suction groove 26, so that a stronger fixation is possible. It becomes. Further, by providing the transparent plate glass 40 with the flange 41 and supporting the flange 41 on the upper surface of the vacuum suction frame 26, the mask M can be more reliably prevented from being bent and displaced.

  Further, the substrate stage 2 is moved stepwise with respect to the mask M in the two directions of the X-axis direction and the Y-axis direction and irradiated with light for pattern exposure at each step, whereby a plurality of patterns of the mask M are formed on the substrate. Since exposure transfer is performed on W, exposure to a large substrate W can be performed with a smaller mask M to reduce cost and increase pattern accuracy. A variety of patterns can be created.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the above-described embodiment, the case where the transparent plate glass 40 is fixedly disposed over substantially the entire area of the vacuum suction frame 26 is taken as an example. Alternatively, the transparent plate glass may be fixedly arranged in part.

In the above embodiment, a combination of a linear guide and a ball screw is used as the feeding means of each stage feeding mechanism. However, the present invention is not necessarily limited to this. For example, a linear motor or the like is used as the feeding means. May be used.
Further, in the above embodiment, the substrate stage 2 is configured to be stepped in the X-axis and Y-axis directions. Instead, the mask stage 1 can be stepped in the X-axis and Y-axis directions together with the irradiation unit. It is good also as a simple structure.

  Furthermore, in the above-described embodiment, the case where the substrate stage 2 is stepped in the biaxial direction with respect to the mask M and the pattern exposure light is irradiated for each step is taken as an example, but the present invention is not limited to this. The present invention is also applied to the case where the substrate stage 2 is moved stepwise in the uniaxial direction with respect to the mask M and light for pattern exposure is irradiated for each step, or in the case of a batch exposure method that does not involve a step operation. Needless to say, you can.

It is explanatory drawing which fractured | ruptured one part for demonstrating the proximity exposure apparatus which is an example of embodiment of this invention. It is the elements on larger scale of FIG. It is the figure seen from the arrow A direction of FIG. It is explanatory drawing for demonstrating the conventional proximity exposure apparatus. It is explanatory drawing for demonstrating the conventional problem.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mask stage 2 Substrate stage 3 Irradiation means W Substrate M Mask 25 Mask holding frame 26 Vacuum suction frame 26a Vacuum suction groove 40 Transparent plate glass (transparent plate member)

Claims (2)

A substrate stage for holding a substrate as a material to be exposed; a mask having a pattern to be exposed; a mask stage for adjusting the orientation of a mask holding frame for holding the mask via a vacuum suction frame; and the substrate A proximity exposure apparatus comprising: irradiation means for irradiating light for pattern exposure toward the mask in order to expose and transfer the pattern of the mask to the substrate in a state where the mask and the mask are interposed through a minute gap;
A transparent plate member is fixedly arranged in the frame of the vacuum suction frame, and the mask is vacuum-sucked by the vacuum suction frame and the transparent plate member by vacuum suction of air between the transparent plate member and the mask. Proximity exposure apparatus characterized by performing.   2. The proximity exposure apparatus according to claim 1, wherein a vacuum suction groove provided in the vacuum suction frame is opened on the mask side surface and the side surface of the transparent plate member.

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