JP2011164595A - Proximity exposing device and proximity exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proximity exposing device and a proximity exposure method capable of averaging a gap between a mask and a workpiece by comparatively simple calculation and improving exposure accuracy. <P>SOLUTION: By a gap sensor 17, a gap between the mask M and the workpiece W is measured in each of four measurement points A, B, C and D. A Z-tilt adjustment mechanism 43 is driven so that, out of the coordinates of four median points K, L, M and N of respective sides of a quadrangle ABCD defined by the four measurement points A, B, C, and D, respective gaps in the coordinates of three median points K, L and M are equalized. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a proximity exposure apparatus and a proximity exposure method.

  Conventionally, various proximity exposure apparatuses for manufacturing color filter substrates and TFT (Thin Film Transistor) substrates of flat panel display devices such as liquid crystal display devices and plasma display devices have been devised. The proximity exposure apparatus holds a mask by a mask holding unit and holds a substrate as a workpiece by a workpiece holding unit and arranges both of them in close proximity to each other. In this case, the posture of the mask or the workpiece is controlled so that the gap between the mask and the workpiece is uniform over the exposure region.

  When a mask pattern is exposed and transferred onto a large substrate, a mask smaller than the work is used, the work holding unit is moved stepwise relative to the mask, and the mask is placed close to the work for each step. A so-called stepwise proximity exposure method is often used in which exposure light is irradiated in the arranged state, and a plurality of patterns drawn on a mask are exposed and transferred onto a substrate.

  For example, when the workpiece holding unit is moved to control the posture of the workpiece, first, it is necessary to calculate the surface on which the workpiece exists as a virtual plane by calculation. For this reason, the distance to the workpiece is measured with reference to the plane of the mask, and the plane on which the workpiece to be controlled exists is calculated from the measurement result. In the conventional calculation method, as shown in FIG. 8, the gap between the mask and the workpiece is measured at three points A, B, and C to measure the plane. As another conventional calculation method, the gap between the mask and the workpiece is measured at three or more measurement points, and the regression plane or virtual plane of the workpiece is obtained from the plane equation by the least square method, and is parallel to the reference plane. An apparatus for setting the tilt of a substrate has been devised (see, for example, Patent Document 1). Further, it is disclosed that a gap is measured at four or more points and a regression plane or a virtual plane is obtained from a plane equation (see, for example, Patent Document 2).

Japanese Patent Publication No. 3-5652 Japanese Patent No. 2860857

  However, when the workpiece posture is measured at three points A, B, and C to obtain a plane on which the workpiece exists as in the prior art, the gaps at the three points can be averaged, but the points shown in FIG. The gap at Δ is highly likely to deviate greatly from the plane, and the gap cannot be averaged over the entire surface of the workpiece exposure area. Further, the calculation methods shown in Patent Documents 1 and 2 have a problem that the calculation of the plane equation is complicated and takes a long processing time.

  The present invention has been made in view of the above-described problems, and its object is to perform proximity exposure that can average the gap between the mask and the workpiece with a relatively simple calculation and improve the exposure accuracy. An apparatus and a proximity exposure method are provided.

The above object of the present invention can be achieved by the following constitution.
(1) a mask holding unit for holding a mask having a pattern to be exposed;
A mask driving unit for driving the mask holding unit;
A work holding unit for holding a work as an exposed material;
A work driving unit for driving the work holding unit;
A gap sensor for measuring a gap between the mask and the workpiece at four measurement points;
Irradiation means for irradiating the workpiece with light for pattern exposure through the mask;
A proximity exposure apparatus that exposes and transfers a pattern of the mask onto the work in a state where the mask and the work are arranged close to each other and facing each other,
Based on the gap between the mask and the workpiece at the four measurement points measured by the gap sensor, four points at the midpoint of each side of the quadrangle defined by the four measurement points A proximity exposure apparatus, comprising: a control unit that drives at least one of the mask driving unit and the work driving unit so that gaps at the coordinates of three midpoints of coordinates are uniform.
(2) A mask holding unit for holding a mask having a pattern to be exposed, a mask driving unit for driving the mask holding unit, a work holding unit for holding a work as an exposed material, and driving the work holding unit A workpiece driving unit that performs measurement, a gap sensor that measures a gap between the mask and the workpiece at four measurement points, and an irradiation unit that irradiates the workpiece with light for pattern exposure via the mask. A proximity exposure method for exposing and transferring a pattern of the mask onto the work in a state where the mask and the work are arranged close to each other and facing each other,
Measuring the gap between the mask and the workpiece at the four measurement points by the gap sensor;
The mask driving unit and the work are arranged so that gaps at the coordinates of the three midpoints of the four coordinates of the midpoint of each side of the quadrangle defined by the four measurement points are uniform. Driving at least one of the drive units;
A proximity exposure method comprising:

  According to the proximity exposure apparatus and the proximity exposure method of the present invention, the gap between the mask and the workpiece is measured by the gap sensor at the four measurement points, and each of the sides of the quadrangle defined by the four measurement points is measured. Since at least one of the mask drive unit and the workpiece drive unit is driven so that the gaps at the three midpoint coordinates are uniform among the four midpoint coordinates, the remaining midpoints The gap between the mask and the substrate at the four measurement points can be averaged by relatively simple calculation, and the exposure accuracy can be improved.

It is a partially exploded perspective view for explaining a proximity exposure apparatus according to the present invention. It is a front view of the proximity exposure apparatus shown in FIG. It is an expansion perspective view of the mask holding | maintenance part shown in FIG. It is a figure for demonstrating the plane structure of the workpiece | work at the time of performing gap control. It is a figure which shows the coordinate of a gap sensor by making z coordinate of a mask into z = 0. It is a figure for demonstrating that the midpoint of arbitrary four points which exist on space exists on the same plane. (A) is a figure for demonstrating the planar structure of the workpiece | work at the time of performing the conventional gap control, (b) is a figure for demonstrating the planar structure of the workpiece | work at the time of performing the gap control of this invention. It is. It is a figure for demonstrating the plane structure of the workpiece | work at the time of performing the conventional gap control.

  Hereinafter, an exposure apparatus and an exposure method according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the proximity exposure apparatus 1 includes a mask stage 10 that holds a mask M, a work stage (work holding unit) 20 that holds a glass substrate (work as an object to be exposed) W, and pattern exposure. Illumination optical system 30 as an irradiating means for irradiating light, a work stage moving mechanism 40 for moving the work stage 20 in the X-axis, Y-axis, and Z-axis directions and adjusting the tilt of the work stage 20, and a mask And an apparatus base 50 that supports the stage 10 and the work stage moving mechanism 40.

  A glass substrate W (hereinafter, simply referred to as “work W”) is disposed to face the mask M, and a surface (on the side facing the mask M) is used for exposure transfer of the mask pattern drawn on the mask M. ) Is coated with a photosensitive agent. The mask M is made of fused quartz and has a rectangular shape.

  For convenience of explanation, the illumination optical system 30 will be described. The illumination optical system 30 is, for example, a high-pressure mercury lamp 31 that is a light source for ultraviolet irradiation, and a concave mirror 32 that collects light emitted from the high-pressure mercury lamp 31. Two types of optical integrators 33 that are switchably arranged near the focal point of the concave mirror 32, plane mirrors 35 and 36 and a spherical mirror 37 for changing the direction of the optical path, and between the plane mirror 35 and the optical integrator 33 And an exposure control shutter 34 that controls the opening and closing of the irradiation light path.

  As shown in FIGS. 1 to 3, the mask stage 10 includes a mask stage base 11 in which a rectangular opening 11 a is formed at the center, and an X axis, a Y axis, and θ on the opening 11 a of the mask stage base 11. A mask holding frame (mask holding unit) 12 that is mounted so as to be movable in the direction, a chuck unit 14 that is attached to the mask holding frame 12 and holds the mask M by suction, and the mask holding frame 12 and the chuck unit 14 are connected to the X axis. , Y axis, θ direction, and a mask position adjusting mechanism (mask driving unit) 16 for adjusting the position of the mask M held by the mask holding frame 12.

  The mask stage base 11 is supported by a column 51 standing on the apparatus base 50 and a Z-axis moving device 52 provided on the upper end of the column 51 so as to be movable in the Z-axis direction, and is disposed above the work stage 20. Is done. The Z-axis moving device 52 includes, for example, an electric actuator including a motor and a ball screw, a pneumatic cylinder, or the like, and moves the mask stage 10 up and down to a predetermined position by performing a simple vertical movement. The Z-axis moving device 52 is used for exchanging the mask M, cleaning the work chuck 21, and the like.

  The mask position adjusting mechanism 16 includes one Y-axis direction driving device 16y attached to one side along the X-axis direction of the mask holding frame 12 and two Xs attached to one side along the Y-axis direction of the mask holding frame 12. An axial drive device 16x.

  The mask position adjusting mechanism 16 moves the mask holding frame 12 in the Y-axis direction by driving one Y-axis direction driving device 16y, and drives the two X-axis direction driving devices 16x equally. Thus, the mask holding frame 12 is moved in the X-axis direction. Further, the mask holding frame 12 is moved in the θ direction (rotated about the Z axis) by driving one of the two X-axis direction driving devices 16x.

  Further, on the upper surface of the mask stage base 11, as shown in FIG. 3, a gap sensor 17 for measuring a gap between the opposing surfaces of the mask M and the workpiece W, an alignment mark of the mask M, and an alignment mark of the workpiece W are provided. And an alignment camera 18 for imaging. The gap sensor 17 and the alignment camera 18 are held so as to be movable in the X-axis and Y-axis directions via the moving mechanism 19 and are arranged in the mask holding frame 12.

  For example, the gap sensor 17 applies laser light from the light projecting unit to the lower surface of the mask M and the upper surface of the work W, receives the reflected light from each surface by the light receiving unit, and the gap between the lower surface of the mask M and the upper surface of the work W. A total of four laser sensors are arranged on the inner side of the two sides along the X-axis direction of the mask holding frame 12 and spaced apart from each other in the X-axis direction. The gap sensor 17 is not limited to an optical sensor such as a laser sensor, and may be a non-contact type sensor such as an ultrasonic type or an eddy current type.

  Based on the measurement results obtained by these four gap sensors 17, the amount of parallelism between the opposing surfaces of the mask M and the workpiece W can be detected by performing arithmetic processing in the control unit 70. In accordance with the detected deviation amount, three Z-tilt adjustment mechanisms 43 that can be driven independently from each other, which will be described later, are controlled so that the gap between the opposing surfaces of the mask M and the workpiece W becomes a predetermined value.

  The alignment cameras 18 are arranged in two locations, one at each of the upper positions inside the two sides along the X-axis direction of the mask holding frame 12, approximately in the center of the X-axis direction. Based on the image data, the amount of plane deviation between the mask M and the workpiece W can be detected by performing arithmetic processing in the control unit 70. The mask position adjustment mechanism 16 moves the mask holding frame 12 in the X, Y, and θ directions in accordance with the detected plane deviation amount so as to adjust the orientation of the mask M held on the mask holding frame 12 with respect to the workpiece W. It has become.

  On the upper surface of the mask stage base 11, as shown in FIG. 3, a masking aperture 38 that shields both ends of the mask M as necessary at both ends in the X-axis direction of the opening 11 a of the mask stage base 11. Is provided. The masking aperture 38 is movable in the X-axis direction by a masking aperture drive mechanism 39 including a motor, a ball screw, a linear guide, and the like, and adjusts the shielding area at both ends of the mask M. Note that the masking aperture 38 may be provided not only at both ends in the X-axis direction of the opening 11a but also at both ends in the Y-axis direction of the opening 11a.

  As shown in FIGS. 1 and 2, the work stage 20 is provided on a work stage moving mechanism 40, and includes a work chuck 21 having a suction surface 22 for holding the work W on the work stage 20 on the upper surface. . The work chuck 21 holds the work W by vacuum suction.

  2 and 3, the work stage moving mechanism 40 includes a Y axis feed mechanism 41 that moves the work stage 20 in the Y axis direction, and an X axis feed mechanism 42 that moves the work stage 20 in the X axis direction. And a Z-tilt adjustment mechanism 43 that performs the tilt adjustment of the work stage 20 and finely moves the work stage 20 in the Z-axis direction.

  The Y-axis feed mechanism 41 includes a pair of linear guides 44 installed on the upper surface of the apparatus base 50 along the Y-axis direction, a Y-axis table 45 supported by the linear guide 44 so as to be movable in the Y-axis direction, And a Y-axis feed driving device 46 for moving the axis table 45 in the Y-axis direction. Then, by driving the motor 46c of the Y-axis feed drive device 46 and rotating the ball screw shaft 46b, the Y-axis table 45 is moved along the guide rail 44a of the linear guide 44 together with the ball screw nut 46a, and the workpiece The stage 20 is moved in the Y axis direction.

  The X-axis feed mechanism 42 includes a pair of linear guides 47 installed on the upper surface of the Y-axis table 45 along the X-axis direction, and an X-axis table 48 supported by the linear guide 47 so as to be movable in the X-axis direction. And an X-axis feed drive device 49 that moves the X-axis table 48 in the X-axis direction. Then, by driving the motor 49c of the X-axis feed driving device 49 and rotating the ball screw shaft 49b, the X-axis table 48 is moved along the guide rail 47a of the linear guide 47 together with a ball screw nut (not shown). Then, the work stage 20 is moved in the X-axis direction.

  The Z-tilt adjustment mechanism 43 includes a motor 43a installed on the X-axis table 48, a ball screw shaft 43b rotated by the motor 43a, and a wedge formed in a wedge shape and screwed into the ball screw shaft 43b. And a wedge portion 43d that protrudes in a wedge shape on the lower surface of the work stage 20 and engages with an inclined surface of the wedge nut 43c. In the present embodiment, two Z-tilt adjustment mechanisms 43 are provided on one end side (front side in FIG. 1) in the X-axis direction of the X-axis table 48, and one set on the other end side (the rear side in FIG. A total of 3 units are installed (see FIG. 2), and each is driven and controlled independently. The number of Z-tilt adjustment mechanisms 43 installed is arbitrary.

  In the Z-tilt adjustment mechanism 43, when the ball screw shaft 43b is rotationally driven by the motor 43a, the wedge-shaped nut 43c is horizontally moved in the X-axis direction, and this horizontal movement is caused by the wedge-shaped nut 43c and the wedge portion 43d. The wedge portion 43d is finely moved in the Z direction by being converted into a highly precise vertical fine motion by the action of the slope. Accordingly, by driving the three Z-tilt adjustment mechanisms 43 by the same amount, the work stage 20 can be finely moved in the Z-axis direction, and the three Z-tilt adjustment mechanisms 43 are independently driven. By doing so, the tilt adjustment of the work stage 20 can be performed. As a result, the position of the workpiece stage 20 in the Z-axis and tilt directions can be finely adjusted so that the mask M and the workpiece W face each other in parallel with a predetermined interval.

  Furthermore, as shown in FIGS. 1 and 2, the proximity exposure apparatus 1 is provided with a laser length measuring device 60 that is a position measuring device that detects the position of the work stage 20. The laser length measuring device 60 measures the moving distance of the work stage 20 that occurs when the work stage moving mechanism 40 is driven.

  The laser length measuring device 60 is fixed to a stay (not shown) and arranged along the X-axis direction side surface of the work stage 20, and is fixed to the stay 71 and fixed to the stay 71. A Y-axis mirror 65 disposed along the side surface in the axial direction, and an X-axis direction end of the apparatus base 50, irradiates the X-axis mirror 64 with laser light (measurement light). X-axis length measuring device (length measuring device) 61 and yawing measuring device (length measuring device) 62 for measuring the position of the work stage 20 by receiving the laser beam reflected by the mirror 64 for use, and Y of the apparatus base 50 One Y-axis that is disposed at the end in the axial direction, irradiates the Y-axis mirror 65 with laser light, receives the laser light reflected by the Y-axis mirror 65, and measures the position of the work stage 20. A length measuring device (length measuring device) 63 is provided. .

  In the laser length measuring device 60, the X-axis length measuring device 61, the yawing measuring device 62, and the Y-axis length measuring device 63 irradiate the X-axis mirror 64 and the Y-axis mirror 65 with the laser light applied to the X-axis measuring device. By being reflected by the mirror for mirror 64 and the mirror for Y axis 65, the position of the work stage 20 in the X axis and Y axis directions is measured with high accuracy. Further, the position data in the X-axis direction is measured by the X-axis length measuring device 61, and the position in the θ direction is measured by the yawing measuring device 62. The position of the work stage 20 is calculated by appropriately correcting the position in the X-axis direction, the Y-axis direction, and the θ-direction measured by the laser length measuring device 60.

  1 includes the mask position adjusting mechanism 16, the work stage moving mechanism 40 (the Y-axis feeding mechanism 41, the X-axis feeding mechanism 42, and the Z-tilt adjusting mechanism 43), the moving mechanism 19, and the like. The masking aperture drive mechanism 39 and the like are driven and controlled.

  In the present embodiment, the Z-tilt adjustment mechanism 43 and the control unit 70 constitute the gap adjustment means of the present invention. This gap adjusting means, when exposing and transferring the pattern of the mask M onto the first workpiece W, makes the gap to be a first target value determined in advance based on the measured value of the gap sensor 17. The control unit 70 controls the Z-tilt adjustment mechanism 43 to finely move the work stage 20 up and down, and detects the height of the work stage 20 when the gap is set to the first target value. 2 is stored in the storage area of the control unit 70 as a target value of 2. When the pattern of the mask M is exposed and transferred to the second and subsequent workpieces W, the control unit 70 performs Z-tilt so that the height of the workpiece stage 20 becomes the second target value stored previously. The adjustment mechanism 43 is controlled to finely move the work stage 20 up and down.

  Specifically, when the workpiece W is exposed using the proximity exposure apparatus 1 configured as described above, the first workpiece W after the pre-alignment is first transported to the workpiece stage 20 to be exposed to the exposure position. Retained. Then, the gap between the lower surface of the mask M and the upper surface of the workpiece W is measured by the gap sensor 17, and the control unit 70 performs Z-tilt so that the gap becomes a first target value determined in advance based on the measured value. The adjustment mechanism 43 is controlled to finely move the work stage 20 up and down.

  Then, the height of the work stage 20 when the gap is set to the first target value (for example, the rotation speed or stop phase of the motor 43a of the Z-tilt adjustment mechanism 43 detected by an encoder or the like) is detected. And stored in the storage area of the control unit 70 as the second target value of the first shot. Next, with the gap at the first target value, the illumination optical system 30 irradiates the exposure light for the first shot (first position) as parallel light perpendicular to the mask M and the workpiece W, The pattern of the mask M is exposed and transferred onto the workpiece W.

  In the exposure for the second and subsequent layers, alignment is performed while the alignment camera 18 images the alignment mark on the mask M side and the exposure mark transferred to the workpiece W while the gap is at the first target value. (Alignment) is performed, and the exposure light of the first shot is irradiated from the illumination optical system 30 through the mask M, and the pattern of the mask M is exposed and transferred to the workpiece W.

  After the exposure of the first shot, the control unit 70 lowers the work stage 20 by the Z-tilt adjustment mechanism 43 to enlarge the gap between the lower surface of the mask M and the upper surface of the work W by a certain amount. 20 is moved by one step amount with respect to the mask M and moved to the exposure position of the second shot. Then, again, the control unit 70 controls the Z-tilt adjustment mechanism 43 to finely move the work stage 20 up and down so that the gap measured by the gap sensor 17 becomes the first target value. When the gap is set to the first target value, the height of the work stage 20 of the second shot is stored in the storage area as the second target value (second shot), and the second shot Perform exposure transfer.

  Thereafter, exposure transfer for the third and subsequent shots is performed in the same manner as described above. That is, in each shot, the control unit 70 controls the Z-tilt adjustment mechanism 43 so as to slightly move the work stage 20 up and down so that the gap measured by the gap sensor 17 becomes the first target value. The height of the work stage 20 when the target value is set to 1 is stored in the storage area as the second target value. As a result, the second target value for each shot is stored in the storage area of the control unit 70.

  In this way, after the exposure of all the regions is completed, the control unit 70 lowers the work stage 20 by the Z-tilt adjustment mechanism 43 to enlarge the gap between the lower surface of the mask M and the upper surface of the work W by a certain amount. In this state, the workpiece W is conveyed outside the apparatus, and the step exposure of the first workpiece W is completed.

  Here, the control of the gap between the lower surface of the mask M and the upper surface of the workpiece W will be described in detail. The control unit 70 in the present embodiment measures the gap between the mask M and the workpiece W at the four measurement points A, B, C, and D by the gap sensor 17, and measures the four measurement points A, B, Among the four x and y coordinates of the midpoints K, L, M, and N of each side of the quadrilateral ABCD defined by C and D, the three midpoints K, L, and M in the x and y coordinates Gap control for driving the Z-tilt adjustment mechanism 43 is performed so that each gap is uniform.

That is, as in the conventional gap control, the plane on which the workpiece W exists is obtained based on the x and y coordinates of the three midpoints K, L, and M, and control is performed so that the gap of the plane becomes the target value. To do. Here, the position of the gap sensor is (x1, y1), (x2, y2), (x3, y3), (x4, y4) with the mask center as the origin, as shown in FIG. The z coordinate of the mask surface is 0. The height z coordinate with respect to the x and y coordinates of an arbitrary point on the plane of the workpiece W is a plane equation:
ax + by + cz + d = 0
It is represented by Here, a, b, c, and d are constants. Then, the x and y coordinates of the midpoints K, L and M and the z coordinates at the midpoints K, L and M based on the gaps at the measurement points A, B, C and D (measurement points at both ends of each side) Constants a, b, c and d are obtained. Then, the control unit 70 drives the Z-tilt adjustment mechanism 43 so that the gaps at the midpoints K, L, and M are uniform, so that the workpiece W is parallel to the mask M.

  Since the z coordinate of the mask surface is 0, the measured gap is given as the z coordinate of the workpiece W. That is, the actual z coordinate value of the mask M due to the swell of the mask M is also calculated as the z coordinate of the workpiece W. When the gap control is performed so that the gaps at the x and y coordinates of the three midpoints K, L, and M are uniform, the gap at the remaining midpoint N is also uniform.

  In the following, it will be proved that the midpoints of any four points existing in space are on the same plane.

The equation of the plane is ax + by + cz + d = 0
Then, the coefficient of the plane equation formed from three points (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) is
a = {(y2-y1) * (z3-z1)}-{(z2-z1) * (y3-y1)}
b = {(z2-z1) * (x3-x1)}-{(x2-x1) * (z3-z1)}
c = {(x2-x1) * (y3-y1)}-{(y2-y1) * (x3-x1)}
d = − {(x1 × a) + (y1 × b) + (z1 × c)}
Can be obtained.

Next, with reference to FIG. 6, a rectangle ABCD and the midpoints K, L, M, and N of each vertex will be considered.
When the coordinates of each vertex of the rectangle ABCD are (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), (x4, y4, z4), the midpoint coordinates K, L , M and N are ((x1 + x2) / 2, (y1 + y2) / 2, (z1 + z2) / 2), ((x2 + x3) / 2, (y2 + y3) / 2, (z2 + z3) / 2), ((x3 + x4) / 2, (y3 + y4) / 2, (z3 + z4) / 2), ((x4 + x1) / 2, (y4 + y1) / 2, (z4 + z1) / 2) and the coefficients of the plane equation that can be formed from the three points K, L, and M are ,
a = {(y3-y1) * (z3-z1 + z4-z2)}-{(z3-z1) * (y3-y1 + y4-y2)} / 4
= {(Y3-y1) * (z4-z2)}-{(z3-z1) * (y4-y2)} / 4
b = {(z3-z1) * (x3-x1 + x4-x2)}-{(x3-x1) * (z3-z1 + z4-z2)} / 4
= {(Z3-z1) * (x4-x2)}-{(x3-x1) * (z4-z2)} / 4
c = {(x3-x1) * (y3-y1 + y4-y2)}-{(y3-y1) * (x3-x1 + x4-x2)} / 4
= {(X3-x1) * (y4-y2)}-{(y3-y1) * (x4-x2)} / 4
d = − [{(x1 + x2) × a} + {(y1 + y2) × b} + {(z1 + z2) × c}] / 2
It becomes.

On the other hand, the distance L0 between the plane ax + by + cz + d = 0 and the point (x0, y0, z0) is



Can be obtained.

The molecular part of the distance between 3 points K, L, M and N is
Δ = [{(x4 + x1) × a} + {(y4 + y1) × b} + {(z4 + z1) × c}] / 2
− {(X1 + x2) × a} + {(y1 + y2) × b} + {(z1 + z2) × c}] / 2
= [{(X4-x2) * a} + {(y4-y2) * b} + {(z4-z2) * c}] / 2
When a, b, and c are substituted, Δ becomes 0.
As described above, the point N exists on a plane formed by the three points K, L, and M. As a result, it was proved that the position of the remaining midpoint N can be obtained from the three midpoints K, L, and M of the quadrilateral ABCD defined by the four measurement points.

  Here, it is assumed that the gaps at the four vertices of the square ABCD of each side 1000 [mm] are A: 250 [μm], B: 320 [μm], C: 270 [μm], and D: 290 [μm]. Gap control by a conventional plane including three points A, B and C (see FIG. 7A) and a plane including the midpoint of each of the four points A, B, C and D of the present invention (FIG. 7 ( The gap control according to b) was performed. Table 1 shows the coordinates at each point, and Table 2 shows the error from the target gap at each point. The target gap is set to 300 [μm].

  In gap control by a plane including three points A, B, and C, the constants of the plane equation consisting of points A, B, and C: ax + by + cz + d = 0 are a = 50, b = 70, c = 1000000, d = −260000. Thus, the distance between the plane consisting of the points A, B and C and the point D is as large as 90 [μm]. On the other hand, in the gap control by the plane including the midpoint of each of the four points A, B, C, D, each constant of the plane equation consisting of the points K, L, M: ax + by + cz + d = 0 is a = 2.5, b = 12.5, c = 500,000, d = -141250, and the distance between the plane composed of the points K, L, and M and the points A, B, C, and D is as small as 22.5 [μm], respectively, and the gap It can be seen that is averaged.

  Therefore, according to the proximity exposure apparatus 1 and the proximity exposure method of the present embodiment, the gap between the mask M and the workpiece W is measured by the gap sensor 17 at the four measurement points A, B, C, and D. Three midpoints K, L among the four x, y coordinates of the midpoints K, L, M, N of each side of the quadrilateral ABCD defined by the measurement points A, B, C, D Since the Z-tilt adjustment mechanism 43 is driven so that the gaps in the x and y coordinates of M are uniform, the gaps at the remaining midpoint N are also uniform. Thereby, the gap between the mask M and the workpiece W at the four measurement points can be averaged by a relatively simple calculation using the same three points as the conventional gap control shown in FIG. Can be improved.

  In addition, when the feedback control is performed to finely move the mask M and the workpiece W relatively finely so that the difference between the measured value of the gap sensor 17 and the first target value becomes zero, the workpiece holding unit 20 Since the height position is stored as the second target value, at the time of exposure of the second and subsequent workpieces W, the height position of the workpiece holding unit 20 is simply controlled to become the second target value. There is no need to perform feedback control, and throughput can be improved.

In addition, this invention is not limited to each embodiment and modification which were mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the above embodiment, the Z-tilt adjustment mechanism 43 is driven so that the gaps at the coordinates of the three midpoints are uniform. However, the mask driving unit that moves the mask M in the Z direction is provided. If so, the mask drive unit may be driven. Further, the gap adjustment may be performed by relatively moving both the Z-tilt adjustment mechanism 43 and the mask driving unit.

1 proximity exposure apparatus 10 mask stage (mask holding unit)
17 Gap sensor 20 Work stage (Work holding part)
30 Illumination optical system (irradiation means)
40 Work stage moving mechanism (work drive unit)
43 Z-tilt adjustment mechanism (gap adjustment means)
70 Control unit (gap adjusting means, plate thickness difference calculating means)
76 Thickness measuring device (Thickness difference calculation means)
M Mask W Glass substrate (Workpiece as exposed material)

Claims (2)

A mask holding unit for holding a mask having a pattern to be exposed;
A mask driving unit for driving the mask holding unit;
A work holding unit for holding a work as an exposed material;
A work driving unit for driving the work holding unit;
A gap sensor for measuring a gap between the mask and the workpiece at four measurement points;
Irradiation means for irradiating the workpiece with light for pattern exposure through the mask;
A proximity exposure apparatus that exposes and transfers a pattern of the mask onto the work in a state where the mask and the work are arranged close to each other and facing each other,
Based on the gap between the mask and the workpiece at the four measurement points measured by the gap sensor, four points at the midpoint of each side of the quadrangle defined by the four measurement points A proximity exposure apparatus, comprising: a control unit that drives at least one of the mask driving unit and the work driving unit so that gaps at the coordinates of three midpoints of coordinates are uniform. A mask holding unit that holds a mask having a pattern to be exposed, a mask driving unit that drives the mask holding unit, a work holding unit that holds a work as an exposure material, and a work drive that drives the work holding unit A gap sensor for measuring a gap between the mask and the workpiece at four measurement points, and irradiation means for irradiating the workpiece with light for pattern exposure via the mask. A proximity exposure method for exposing and transferring a pattern of the mask onto the work in a state where the mask and the work are arranged close to each other and facing each other,
Measuring the gap between the mask and the workpiece at the four measurement points by the gap sensor;
The mask driving unit and the work are arranged so that gaps at the coordinates of the three midpoints of the four coordinates of the midpoint of each side of the quadrangle defined by the four measurement points are uniform. Driving at least one of the drive units;
A proximity exposure method comprising: