JP2007219011A - Maskless exposure apparatus and exposure method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a relative angle between a DMD (spatial optical modulator) and a substrate with high accuracy in an inexpensive configuration. <P>SOLUTION: A rotating table 13 the rotation center of which can be moved in XY directions is provided and a substrate 6 as an exposure object is mounted on the rotating table 13 and preliminarily rotated by a predetermined angle θ with respect to the Y axis prior to starting exposure. The substrate 6 in the rotated state is subjected to XY axes complementary control so as to draw a pattern on the substrate 6 by exposure by subjecting each mirror M of the DMD 3 to on-off control based on time-series exposure data while the substrate 6 is inclined in the direction of the angle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention exposes a printed circuit board, a semiconductor, a photosensitive dry film on a liquid crystal surface, a liquid resist or the like using a spatial light modulator (Digital Micromirror Device-hereinafter referred to as “DMD”) without using a pattern mask. The present invention relates to a maskless exposure apparatus that exposes (draws) an electric circuit or the like on an object (hereinafter referred to as “substrate”) with light such as ultraviolet light, and an exposure method of the maskless exposure apparatus.

  6A and 6B are explanatory views of a conventional exposure apparatus using a DMD. FIG. 6A is an overall configuration diagram, FIG. 6B is a plan view of the DMD, and FIG. 6C is a partially enlarged view of FIG. FIGS. 7A and 7B are diagrams showing the state of light irradiated on the object to be exposed, where FIG. 7A shows the operation of the microlens and FIG. 7B shows the exposure result.

  The light output from the light source 1 is converted into parallel light 1 a by the collimator lens 2 and enters the DMD 3. As shown in FIG. 6 (b), the DMD 3 includes m square mirrors M each having a reflecting surface of 16 μm in the horizontal direction (the horizontal direction in the figure) and the vertical direction (the vertical direction in the figure). .) Are arranged in six rows. As shown in FIG. 6C, a gap g of 1 μm is provided between the mirror M and the adjacent mirror M. The mirrors M in each row are arranged so as to be shifted by 2.83 μm ((16 + 1) / 6 μm) from the mirrors M in the adjacent upper and lower rows. Each mirror M has a pair of end portions Ma in the diagonal direction as fulcrums, and the other end portion Mb can rotate about 10 degrees. The DMD 3 is positioned so that the lateral direction is perpendicular to the moving direction of the substrate 6 (the left-right Y direction in FIG. 6A).

  The DMD control device 4 individually controls each mirror M of the DMD 3 on / off (rotation control). When the mirror M is on, the parallel light 1a is reflected by the incident mirror M, collected by the microlens 5 provided for each mirror M, and incident on the substrate 6. When the mirror M is off, the parallel light 1a is separated from the substrate 6. The incident light enters. The microlens 5 is provided for each mirror M, and as shown in FIG. 7A, the parallel light 1a reflected by the mirror M indicated by a two-dot chain line in the figure is converged in each side direction, and on the substrate 6. Thus, each spot S has a size of 2.83 μm on one side. The substrate 6 is placed on the table 7 and is movable on the base 9 in the Y direction.

  With the above configuration, for example, when the mirrors M11 to M16 shown in FIG. 6B are turned on every time the table moves 17 μm while moving the substrate 6 in the Y direction, as shown in FIG. 7B. The spots S11 to S16 are irradiated onto the substrate 6, and the substrate 6 can be exposed to a linear pattern having a Y direction of 2.8 μm and an X direction of 17 μm (Patent Document 1).

  Further, in Patent Document 1, instead of disposing the mirrors M in a shifted manner for each column, the mirrors M are arranged in a lattice shape in two orthogonal directions, and the whole is P / n (where P is the mirror M It is disclosed that the arrangement pitch in the vertical direction and n may be inclined in the movement direction by the number of columns).

  All DMDs 3 that are available (commercially available) at this time have mirrors M arranged in two orthogonal directions, and DMDs 3 in which the positions of mirrors M are shifted for each column cannot be obtained. Therefore, as disclosed in Patent Document 1, the DMD 3 is inclined with respect to the moving direction of the substrate 5, that is, the Y axis.

  Next, the angle θ at which the DMD 3 is tilted with respect to the Y axis will be described.

  FIG. 8 is a diagram for explaining the angle θ. In the figure, only the center of the mirror M is shown.

When exposing a certain location, the location is usually exposed with a plurality of mirrors. In this way, the exposure result can be made uniform. For example, if DMD3 in which the mirror M is vertically arranged N (N = 12) and m is arranged horizontally is used and the number of overlapping points k is k = 3, the DMD3 is moved in the moving direction of the substrate 5 as shown in FIG. The angle θ is inclined with respect to the angle θ, where θ = tan ⁻¹ (k / N).

  If the exposure interval (scan line interval) is C, the pitch of the mirror M is d, the moving speed of the substrate 5 is V, and the on / off frequency of the mirror M is H, the scan line interval C is C = V / H = It is expressed by dsin θ. That is, the angle θ can be expressed by the following formula 1 using the pitch d, the moving speed V, and the on / off frequency H of the mirror M.

θ = sin ⁻¹ V / Hd Equation 1
JP-A-11-320968

  For example, in the case of 0.7 SVGA (Super Video Graphics Array) which is a commercially available DMD, 648 mirrors M in the vertical direction and 800 in the horizontal direction (11.015 × 13.599 mm) are arranged and stored in one case. Has been. On the other hand, the substrate size is usually 300 × 300 in width to 500 × 600 mm in length. Therefore, when the entire surface of the substrate is to be exposed by one DMD, even if the overlapping point number k is k = 1 (angle θ = 1 / 648≈0), it is necessary to make 23 reciprocations in the case of the substrate 6 having a width of 500 mm. Yes, production efficiency is poor. Therefore, if a plurality of DMDs are arranged side by side in accordance with the horizontal width of the substrate 5 (46 or more in the case of the substrate 6 having a width of 500 mm), the number of movements of the table can be reduced to one, so that the processing efficiency can be improved. it can.

  However, when changing the value of the scan line interval C, the moving speed V of the substrate 5 or the on / off frequency H of the mirror M, it is necessary to change the value of the angle θ according to the change. In such a case, for example, if the setting of the angle θ is shifted by 0.001 °, a deviation of 8.73 μm (500 × tan 0.001 °) occurs at both ends in the case of the substrate 6 having a vertical length of 500 mm. Therefore, it is necessary to accurately position the angles θ of all DMDs 3 (for example, 46), and the apparatus becomes expensive.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a maskless exposure method and a maskless exposure apparatus capable of setting a relative angle between a DMD and a substrate with high accuracy with a low cost.

  In order to solve the above-described problem, the first means moves the spatial light modulator, in which a number of micromirrors are aligned in two orthogonal directions, and the object to be exposed while relatively moving the micromirror. In the maskless exposure apparatus that individually controls and makes light from a light source incident on the surface of the exposure object to expose a desired pattern on the surface of the exposure object, the spatial light modulator and the exposure object And moving the exposure object and the spatial light modulator at an angle θ that intersects both of the two alignment directions of the micromirrors. A desired pattern is exposed on the surface of the object to be exposed while being relatively moved in a maintained state.

  The second means individually controls the micromirrors while relatively moving a spatial light modulator in which a number of micromirrors are arranged in two orthogonal directions and an object to be exposed. In a maskless exposure apparatus that exposes a desired pattern on the surface of the exposure object by causing the light of the light to enter the surface of the exposure object, a rotation table whose center of rotation is movable in the X and Y directions is provided. The exposure object is placed on the surface of the exposure object while moving the exposure object while maintaining an angle θ in which the direction of travel of the exposure object intersects with any of the two alignment directions of the micromirrors. A desired pattern is exposed on the surface.

  The third means individually controls the micromirrors while relatively moving a spatial light modulator in which a large number of micromirrors are arranged in two orthogonal directions and an object to be exposed. In a maskless exposure apparatus that exposes a desired pattern on the surface of the exposure object by making the light incident on the surface of the exposure object, a rotatable holding table is provided, and the spatial light modulator is provided on the holding table In addition, the exposure object is placed on an XY table that is movable in the XY directions, and the traveling direction of the exposure object is maintained at an angle θ that intersects both of the two alignment directions of the micromirrors. Then, a desired pattern is exposed on the surface of the exposure object while moving the exposure object.

  The fourth means individually controls the micromirrors while relatively moving a spatial light modulator in which a large number of micromirrors are aligned and arranged in two orthogonal directions and an exposure target. In the exposure method of a maskless exposure apparatus that causes a desired pattern to be exposed on the surface of the exposure object by causing the light of the light to enter the surface of the exposure object, the spatial light modulator and the exposure object are A desired pattern is exposed on the surface of the object to be exposed while moving in a direction intersecting with any of two mirror alignment directions.

  According to the present invention, the angle θ between the DMD and the substrate can be set accurately and easily, so that the pattern can be exposed with high accuracy.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a first overall configuration diagram of a maskless exposure apparatus according to Example 1 of the present embodiment. Components having the same or the same functions as those in FIG. . FIG. 2 is a plan view of the main part of FIG. 1, in which a solid line indicates the start of exposure and a two-dot chain line indicates the end of exposure.

  The XYθ table 10 includes an X table 11 movable on the base 9 in the X direction, a Y table 12 movable on the X table 11 in the Y direction, and a θ table 13 rotatably supported on the Y table 12. It consists of and. The rotation center O of the θ table 13 is aligned with the center of the Y table 12 as shown in FIG. The θ table 13 is position feedback controlled by a motor equipped with an encoder, and is positioned in the rotational direction with an accuracy of 0.05 degrees. Each of the X table 11 and the Y table 12 is supported by a linear guide device (not shown), is subjected to position feedback control by a linear scale (not shown), and is positioned with an accuracy of ± 1 μm.

  The suction table 14 is fixed on the θ table 13. The surface of the suction table 14 is provided with a large number of holes communicating with an internal cavity, and the cavity is connected to a vacuum source 15. The substrate 6 is sucked and fixed to the suction table 14. As shown in FIG. 2, alignment marks (positioning marks) 17 are provided at the four corners of the surface of the substrate 6.

  At a position facing the XYθ table 10, a light source 1 and a collimator lens 2, which are illumination optical systems, a plurality of DMDs 3 (here, six), a micro lens 5 which is an imaging optical system, and a CCD camera 20 are arranged. Yes. As shown in FIG. 2, the DMDs 3 are arranged in two rows in the Y direction so that each lateral direction is in the X direction and the distance between the mirrors M is equal to the X direction, and is held by a holder (not shown). ing. The optical axis of the CCD camera 20 is perpendicular to the surface of the XYθ table 10.

  Next, the control circuit will be described.

  FIG. 3 is a connection diagram of the control circuit in this embodiment.

  The DMD 3 is connected to the DMD control device 4. The DMD control device 4 is connected to the control device 30 and a linear scale. The linear scale is connected to the DMD control device 4 and the control device 30. The CCD camera 20 is connected to the control device 30 via the image processing device 21. The control device 30 includes a storage unit and a calculation unit.

  The DMD control device 4 performs on / off control of the mirror M based on the exposure data instructed from the control device 30 while referring to the detected value of the linear scale (that is, the current position of the X table 11 and the Y table 12).

  The controller 30 converts the format of CAD data in the storage unit inputted in advance to create vector data, and then the actual coordinate value of the alignment mark 17 on the substrate 6 measured by the CCD camera 20 and the design alignment mark 17. Based on these coordinate values, the created vector data is corrected so as to follow the geometric distortion of the substrate 6 by, for example, affine transformation. Then, the obtained vector data is converted into angle θ coordinates, which will be described later, and then converted into raster data to obtain the XY coordinates of the final spot S to obtain time-series exposure data.

  Next, the operation will be described.

Procedure 1. The angle θ is obtained from Equation 1 from the designated exposure speed V, the on / off frequency H of the mirror M, and the pitch d of the mirror M known in advance.
Procedure 2. The θ table 13 is rotated by an angle θ.

    Procedure 3. The X table 11 and the Y table 12 are moved, and the alignment mark 17 on the substrate 6 is imaged by the CCD camera 20, and the actual coordinates of each alignment mark 17 are obtained. Procedure 4. The geometric distortion of the substrate 6 is obtained from the actual coordinates of the alignment mark 17 and the design coordinates.

    Procedure 5. After the vector data corrected so as to follow the geometric distortion of the substrate 6 is converted into the angle θ coordinate, it is converted into raster data to obtain the final XY coordinates for the spot S, which are used as time-series exposure data.

    Procedure 6. Thereafter, exposure is performed based on time-series exposure data as in the conventional case while the substrate 6 is skewed in the angle θ direction indicated by the arrow in FIG. 2 by performing XY axis complement control. That is, the DMD control device 4 controls the mirror M on and off with reference to the detection values of the linear scales indicating the positions of the X table 11 and the Y table 12.

In this embodiment, the X table 11 and the Y table 12 can be positioned with an accuracy of ± 1 μ. Therefore, when the table stroke is 500 mm, the positioning accuracy of the angle θ is 0.000115 ° (θ = tan ⁻¹ (0.001 / 500)).

  Also, the actual coordinate values of the alignment marks 17 provided in advance at the four corners of the substrate 6 are obtained, and the geometrical distortion of the substrate 6 is measured by comparing the actual coordinate values with the design coordinate values, thereby exposing exposure data ( The coordinates of the drawing data) are determined, that is, the exposure position is changed in accordance with the geometric distortion of the substrate. For example, even when the distance between the two lands is narrow, a line that does not touch either can be exposed. it can.

  In addition, since the exposure position is determined based on the actual coordinate value of the alignment mark 17 and the design coordinate value, even if there is an error (for example, 0.1 degree) in the positioning angle of the θ table 13, it is canceled. It is possible to perform exposure with excellent accuracy.

  When the positioning accuracy of the θ table 13 is high and the geometric distortion of the substrate 6 is small, exposure with excellent accuracy can be performed even if the steps 3 and 4 are omitted.

  Further, instead of providing the θ table 13, all DMDs 3 may be placed on one rotatable holding table and the holding table may be rotated.

  FIG. 4 is an overall configuration diagram of the maskless exposure apparatus according to the second embodiment, and the θ table 13 in the first embodiment is not provided.

  In the case of this embodiment, the procedure 2 in the first embodiment cannot be performed. For this reason, if the number of DMDs 3 is the same as that in the first embodiment, as shown in FIG. 5, the region that cannot be irradiated (the region indicated by hatching in the drawing) increases as the angle θ increases. However, since the θ table is unnecessary, the configuration is simplified.

  Since the operation is substantially the same as that of the first embodiment, a duplicate description is omitted.

1 is an overall configuration diagram of a maskless exposure apparatus according to Embodiment 1 of the present invention. It is a principal part top view of FIG. It is a connection diagram of the control circuit in Example 1 of the present invention. It is a whole block diagram of the maskless exposure apparatus which concerns on Example 2 of this invention. It is a principal part top view of FIG. It is explanatory drawing of the conventional exposure apparatus. It is explanatory drawing of an exposure procedure. It is a figure for demonstrating an exposure procedure.

Explanation of symbols

13 Rotary table 6 Substrate (object to be exposed)
θ Predetermined angle 3 DMD (spatial light modulator)
M DMD mirror

Claims (5)

The micromirrors are individually controlled while relatively moving a spatial light modulator in which a large number of micromirrors are arranged in two orthogonal directions and an object to be exposed, and light from a light source is exposed to the object to be exposed. In a maskless exposure apparatus that exposes a desired pattern on the surface of the exposure object by being incident on the surface of the object,
A moving means for relatively moving the spatial light modulator and the exposure object in two orthogonal directions;
The moving means moves the exposure object and the spatial light modulator relative to each other on the surface of the exposure object while maintaining an angle θ intersecting with both of the two alignment directions of the micromirrors. A maskless exposure apparatus that exposes a desired pattern. The micromirrors are individually controlled while relatively moving a spatial light modulator in which a large number of micromirrors are arranged in two orthogonal directions and an object to be exposed, and light from a light source is exposed to the object to be exposed. In a maskless exposure apparatus that exposes a desired pattern on the surface of the exposure object by being incident on the surface of the object,
It has a rotary table whose center of rotation is movable in the XY direction.
The exposure object is placed on the rotary table, and the exposure object is moved while moving the exposure object while maintaining an angle θ in which the traveling direction of the exposure object intersects both of the two alignment directions of the micromirrors. A maskless exposure apparatus that exposes a desired pattern on the surface of an object. The micromirrors are individually controlled while relatively moving a spatial light modulator in which a large number of micromirrors are arranged in two orthogonal directions and an object to be exposed, and light from a light source is exposed to the object to be exposed. In a maskless exposure apparatus that exposes a desired pattern on the surface of the exposure object by being incident on the surface of the object,
A rotatable holding base,
An XY table movable in XY directions;
With
The spatial light modulator is mounted on the holding table, the exposure object is mounted on the XY table, and the traveling direction of the exposure object intersects with any of the two alignment directions of the micromirrors. A maskless exposure apparatus that exposes a desired pattern on the surface of the exposure object while moving the exposure object while maintaining the angle θ to be maintained. It further comprises imaging means for imaging the surface of the exposure object,
The maskless exposure apparatus according to claim 1, wherein the imaging unit is disposed on the spatial light modulator side. The micromirrors are individually controlled while relatively moving a spatial light modulator in which a large number of micromirrors are arranged in two orthogonal directions and an object to be exposed, and light from a light source is exposed to the object to be exposed. In an exposure method of a maskless exposure apparatus, which is incident on the surface of an object and exposes a desired pattern on the surface of the exposure object,
A maskless device that exposes a desired pattern on the surface of the exposure object while moving the spatial light modulator and the exposure object in a direction intersecting any of two alignment directions of the micromirrors. Exposure method of exposure apparatus.

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