JP5604745B2 - Exposure equipment - Google Patents

Description

  The present invention relates to an exposure apparatus that scans and exposes a light beam in a direction intersecting the transport direction of the object to be exposed while transporting the object to be exposed in a certain direction, and in particular, scanning of the light beam that scans on the object to be exposed. The present invention relates to an exposure apparatus that attempts to shorten the tact of the exposure process by shortening the distance.

  In this type of conventional exposure apparatus, a single laser beam emitted by being modulated on / off by an optical switch is crossed with the conveyance direction of the exposure object by a polygon mirror while the exposure object is conveyed in a certain direction. The scanning is reciprocated in the direction, and the light is condensed and exposed on the object to be exposed by the fθ lens (see, for example, Patent Document 1).

JP 2005-317800 A

  However, in such a conventional exposure apparatus, since a single light beam reciprocally scans the entire width of the exposure area on the object to be exposed, the scanning distance of the light beam has become long. Therefore, in order to prevent an unexposed portion from occurring in the transport direction of the object to be exposed, there has been a problem that the transport speed of the object to be exposed has to be slowed down and the tact time of the exposure process becomes long.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an exposure apparatus that addresses such problems and shortens the scanning distance of the light beam that scans the object to be exposed to shorten the tact time of the exposure process. .

  In order to achieve the above object, an exposure apparatus according to the present invention comprises a conveying unit that conveys an object to be exposed at a constant speed in a line at a constant arrangement pitch in a direction that intersects the conveying direction of the object to be exposed. A pattern generator that divides and emits laser light expanded in one direction into a plurality of laser beams arranged in a line at a constant arrangement pitch by a plurality of optical switches arranged; Optical scanning means for simultaneously reciprocally scanning the region between the adjacent laser beams with the plurality of laser beams to be irradiated on the exposure body, and condensing the plurality of laser beams to be reciprocated on the object to be exposed and an fθ lens, and a control means for controlling on / off driving of the plurality of optical switches of the pattern generator.

  With such a configuration, while the object to be exposed is conveyed in a certain direction at a constant speed by the conveying means, it is arranged in a line at a constant arrangement pitch in the direction intersecting with the conveying direction of the object to be exposed under the control by the control means. Multiple optical switches of the pattern generator are turned on / off, and the laser light expanded in one direction is divided into multiple laser beams arranged in a line at a fixed array pitch by the multiple optical switches and emitted from the pattern generator. Then, a plurality of laser beams to be irradiated onto the object to be exposed by the optical scanning means are simultaneously reciprocated in a region between adjacent laser beams, and a plurality of laser beams to be reciprocated by the fθ lens are condensed on the exposed body. To do.

  In addition, each optical switch of the pattern generator is provided with electrodes on opposing surfaces parallel to the major axis of a prismatic switching element made of an electro-optic crystal material, and a pair of both ends on the major axis direction of the switching element. The polarizing elements are arranged in crossed Nicols. As a result, electrodes are provided on the opposing surfaces parallel to the major axis of the prismatic switching element made of an electro-optic crystal material, and a pair of polarizing elements are arranged in crossed Nicols on both end surfaces in the major axis direction of the switching element. The emission of each laser beam is turned on / off by each optical switch of the pattern generator configured as described above.

  Further, the optical scanning means is an optical deflection mirror disposed between the fθ lens and another fθ lens disposed between the pattern generator and the fθ lens so as to face the fθ lens in a mirror-symmetric manner. is there. Thus, a plurality of laser beams are simultaneously reciprocally scanned by an optical deflection mirror disposed between the fθ lens and another fθ lens disposed symmetrically opposite to the fθ lens between the pattern generator and the fθ lens. To do.

  The light deflection mirror is a galvanometer mirror. Thereby, a plurality of laser beams are simultaneously reciprocated by the galvanometer mirror.

  Further, the light deflection mirror is a polygon mirror. Thereby, a plurality of laser beams are simultaneously reciprocated by the polygon mirror.

  Furthermore, the optical scanning unit is an acousto-optic element disposed between the fθ lens and the transport unit. As a result, a plurality of laser beams are simultaneously reciprocally scanned with an acousto-optic element disposed between the fθ lens and the conveying means.

  The optical scanning unit is disposed between the fθ lens and another fθ lens disposed between the pattern generator and the fθ lens so as to face the fθ lens in a mirror-symmetric manner, and is in a rectangular block shape. The electro-optic element is provided with a triangular electrode having a side inclined with respect to the optical axis on the opposite surface of the electro-optic crystal material. As a result, the opposing surface of the electro-optic crystal material in the form of a square block is disposed between the fθ lens and another fθ lens disposed opposite to the fθ lens in mirror symmetry between the pattern generator and the fθ lens. A plurality of laser beams are simultaneously reciprocated by an electro-optic element provided with a triangular electrode having a side inclined with respect to the optical axis.

  According to the first aspect of the present invention, the light beam is divided into a plurality of laser beams and simultaneously reciprocated to expose the entire width of the exposure area of the object to be exposed. The scanning distance can be shortened, and the scanning frequency of the laser beam can be increased. Therefore, the conveyance speed of the object to be exposed can be increased, and the tact time of the exposure process can be shortened.

  According to the invention of claim 2, since the optical switch of the pattern generator is formed of the electro-optic crystal material, it is possible to use a laser beam with high energy. Therefore, the scanning speed of the laser beam can be increased to shorten the tact time of the exposure process.

  Furthermore, according to the invention of claim 3, the optical deflection mirror can be arranged at a position where a plurality of laser beams are focused on the optical axis side between the pair of fθ lenses, and the mirror shape of the optical deflection mirror Can be reduced. Therefore, it is possible to reduce the moment of inertia of the light deflection mirror and increase the drive frequency. Thereby, the conveyance speed of a to-be-exposed body can be made faster and the tact of an exposure process can be shortened further.

  Moreover, according to the invention which concerns on Claim 4, the manufacturing cost of an optical deflection | deviation mirror can be made cheap.

  Furthermore, according to the fifth aspect of the present invention, it is possible to shorten the scanning time of the return path of the light beam for reciprocating scanning, and to further increase the scanning frequency of the laser beam.

  According to the invention according to claim 6 or 7, the laser beam can be stably scanned for a long time with little temporal change of the optical scanning means. Therefore, the reliability of the exposure apparatus can be improved.

1 is a schematic diagram showing a first embodiment of an exposure apparatus according to the present invention. It is a perspective view which shows the structure of the optical switch used for the exposure apparatus of this invention. It is a block diagram which shows schematic structure of the control means of the exposure apparatus of this invention. It is explanatory drawing which shows the reciprocating operation | movement of the galvanometer mirror used for the exposure apparatus of this invention. It is a figure explaining the on / off drive of the said optical switch, (a) shows an ON state, (b) shows an OFF state. It is explanatory drawing which shows exposure by the reciprocation operation | movement of one laser beam in the exposure apparatus of this invention. It is a schematic block diagram which shows 2nd Embodiment of the exposure apparatus by this invention. It is a schematic block diagram which shows 3rd Embodiment of the exposure apparatus by this invention. It is a figure which shows one structural example of the optical scanning means of the said 3rd Embodiment, (a) is a front view, (b) is a side view.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing a first embodiment of an exposure apparatus according to the present invention. The exposure apparatus performs exposure by scanning a light beam in a direction intersecting the transport direction of the object to be exposed while transporting the object to be exposed in a fixed direction. The transport unit 1, the exposure optical system 2, and the control And means 3.

  The transport means 1 transports the object to be exposed 4 in a constant direction at a constant speed, and includes an air outlet and a suction port on the upper surface 5a of the stage 5, and adjusts the air jet output and suction force. The exposed object 4 is conveyed while holding both end edges of the exposed object 4 by a conveying mechanism (not shown) in a state where the exposed object 4 is floated on the upper surface 5a of the stage 5 by a certain amount. In FIG. 1, the conveying direction of the object to be exposed 4 is a direction (arrow A direction) from the near side to the back as opposed to the drawing.

  An exposure optical system 2 is disposed above the conveying means 1. The exposure optical system 2 scans the laser beam Lb in a direction (arrow B, C direction) intersecting the conveyance direction of the exposure object 4 and irradiates the surface of the exposure object 4 moving in the arrow A direction. The photosensitive material applied on the surface of the exposure body 4 is exposed, and the pattern generator 6, the optical scanning means 7, and the first fθ lens 8 are arranged in this order from the upstream to the downstream in the traveling direction of the laser beam Lb. It is prepared.

  Here, the pattern generator 6 is a laser beam widened in one direction by a plurality of optical switches 9 (see FIG. 2) arranged in a line at a constant arrangement pitch in a direction intersecting the conveyance direction of the object 4 to be exposed. L is divided into a plurality of laser beams Lb arranged in a line at a constant arrangement pitch and emitted, and as shown in FIG. 2, each optical switch 9 includes a plurality of prismatic prisms made of an electro-optic crystal material. The electrodes 11a and 11b are provided on opposing surfaces parallel to the major axis of the switching element 10, and a pair of polarizing elements are arranged in crossed Nicols on both end surfaces in the major axis direction of the plurality of switching elements 10. . As shown in FIG. 1, the plurality of switching elements 10 are connected to the respective wirings of the wiring board 12 on the transparent wiring board 12 with the long axis direction as a light path. In this state, the switching element assembly 13 is formed in a line.

  In the first embodiment, as shown in FIG. 2, the pair of polarizing elements includes, as an example, a first polarizing beam splitter 14 disposed on the light incident end face 10a side of the electro-optic crystal material; The second polarizing beam splitter 15 disposed on the light exit end face 10b side is shown as being provided in a relationship rotated by 90 ° about the optical axis, but the pair of polarizing elements is a pair of polarizing plates. There may be. Further, the first and second polarizing beam splitters 14 and 15 may be common throughout the switching element assembly 13. Furthermore, in the first embodiment, a plurality of microlenses are arranged in a line at the same pitch as the arrangement pitch of the plurality of switching elements 10 between the first polarizing beam splitter 14 and the switching element assembly 13. The provided lens array 16 is disposed, and the widened laser beam L is divided into a plurality of laser beams Lb by a plurality of microlenses and is condensed on each switching element 10. Thereby, the light utilization efficiency can be improved.

  The laser light L incident on the pattern generator 6 is emitted from the laser light source 17 and guided to the plate-shaped rod lens 19 by the optical fiber 18. After the light intensity distribution is made uniform by the rod lens 19, The beam expander 20 widens the end surface of the rod lens 19 in the long axis direction. Accordingly, the pattern generator 6 is arranged so that the arrangement direction of the microlenses of the lens array 16 and the arrangement direction of the plurality of optical switches 9 coincide with the widening direction of the laser light L.

  The light scanning means 7 simultaneously reciprocates a region between adjacent laser beams Lb with a plurality of laser beams Lb emitted from the pattern generator 6 and irradiating the object 4 to be exposed. a light deflection mirror disposed between the fθ lens 8 and the second fθ lens 21 disposed between the pattern generator 6 and the first fθ lens 8 so as to be opposed to the first fθ lens 8 in a mirror-symmetric manner; Yes, a galvanometer mirror or a polygon mirror. In the following description, the case where the light deflection mirror is the galvanometer mirror 22 will be described. Since the second fθ lens 21 is arranged as described above, it is opposite to the normal use state, and the object plane side in normal use is the light emission side.

  The first fθ lens 8 scans a plurality of laser beams Lb reciprocally scanned by the galvanometer mirror 22 on the exposure object 4 at a constant speed, and the focal position on the image plane side is set on the surface of the exposure object 4. The focal position on the object plane side is substantially matched with the focal position on the object plane side of the second fθ lens 21.

  A control unit 3 is provided in electrical connection with the transport unit 1, the pattern generator 6, the galvano mirror 22, and the laser light source 17. This control means 3 controls the on / off drive of the plurality of optical switches 9 of the pattern generator 6, and as shown in FIG. 3, the transport means drive section 23, the pattern generator drive section 24, and the mirror drive. A unit 25, a laser light source driving unit 26, a calculation unit 27, a memory 28, and a control unit 29 are provided.

  Here, the transport means driving unit 23 controls the drive of the transport means 1 and moves a transport mechanism (not shown) at a constant speed. The pattern generator driving unit 24 controls on / off driving of each optical switch 9 of the pattern generator 6 based on CAD data stored in advance in a memory 28 described later. Control is performed so that each optical switch 9 is driven on and off in the forward path and is always driven off in the backward path. Further, the mirror driving unit 25 drives the galvanometer mirror 22 at a constant frequency Fm. For example, as shown in FIG. 4, the rising time corresponding to the forward scanning time of the laser beam Lb corresponds to T1 and the backward scanning time. It is driven by a sawtooth wave whose fall time is T2. The laser light source drive unit 26 drives the laser light source 17 with a preset output. Further, the calculation unit 27 calculates, for example, the conveyance speed V of the object to be exposed 4, the switching frequency Fs of the optical switch 9, and the like based on preset initial setting values. The memory 28 stores initial setting values of each element and CAD data of the exposure pattern. And the control part 29 integrates and controls the whole apparatus so that each element may drive appropriately.

Next, the operation of the exposure apparatus configured as described above will be described.
First, the exposure pitch P1 in the transport direction (arrow A direction) of the exposure object 4, the exposure pitch P2 in the scanning direction of the laser beam Lb, the driving frequency of the galvano mirror 22 (corresponding to the scanning frequency of the laser beam Lb) Fm, laser beam Initial setting values such as the scanning width W of Lb, the power of the laser light source 17 and the CAD data of the exposure pattern are stored in the memory 28.

  In this case, the conveyance speed V of the object to be exposed 4 is calculated by the calculation unit 27 based on the exposure pitch P1 in the conveyance direction of the object to be exposed 4 and the drive frequency Fm of the galvano mirror 22 in the calculation unit 27. This can be calculated. Further, the switching frequency Fs of the optical switch 9 is determined by the calculation unit 27 based on the exposure pitch P2 in the scanning direction of the laser beam Lb, the scanning width W of the laser beam Lb, and the forward scanning time T1 of the laser beam Lb (see FIG. 4). It is calculated by calculating a relational expression of Fs = W / (P2 · T1). Note that the conveyance speed V of the object to be exposed 4 and the switching frequency Fs of the optical switch 9 may be directly input as initial setting values.

  Next, the object to be exposed 4 is placed on the transport unit 1. When the exposure start switch is turned on, an air layer is formed between the upper surface 5a of the stage 5 of the transport means 1 and the object to be exposed 4, and the object to be exposed 4 is floated by a certain amount and is not shown. Both end edges are held by the transport mechanism and transported at a speed V.

  Laser light L is emitted from the laser light source 17 and is guided to the pattern generator 6 side by the optical fiber 18. Then, after the light intensity distribution is made uniform by the rod lens 19, it is widened in a certain direction (a direction intersecting the transport direction of the exposure object 4) by the beam expander 20 and enters the pattern generator 6.

  In the pattern generator 6, the incident laser light L is first separated into P-polarized light that is transmitted through the polarization plane 14a (see FIG. 2) and S-polarized light that is reflected by the polarization plane 14a by the first polarization beam splitter 14. In the following description, a case where P-polarized light is used for exposure will be described, but S-polarized light may be used.

  The P-polarized laser beam L transmitted through the polarization plane 14a of the first polarization beam splitter 14 is divided into a plurality of laser beams Lb by a plurality of microlenses of the lens array 16, and each of the switching element assemblies 13 in the subsequent stage is divided. The light enters the corresponding switching element 10.

  Each switching element 10 is driven on / off at the switching frequency Fs by the pattern generator driving unit 24 based on the CAD data. The laser beam Lb that has passed through each switching element 10 is limited in transmission by the second polarization beam splitter 15 through the polarization plane 15a (see FIG. 2). For example, as shown in FIG. 5A, when the switching element 10 is turned on, the polarization plane of the P-polarized laser beam Lb incident on the switching element 10 passes through the switching element 10. It is rotated 90 ° to become S-polarized light. At this time, since the first polarization beam splitter 14 and the second polarization beam splitter 15 are arranged so as to be rotated by 90 ° about the optical axis, the S-polarized light emitted from the switching element 10 is The polarization plane 15 a of the second polarization beam splitter 15 has a P-polarization relationship, and can pass through the polarization plane 15 a and reach the object to be exposed 4.

  On the other hand, as shown in FIG. 5B, when the switching element 10 is driven off, the polarization plane of the P-polarized laser beam Lb incident on the switching element 10 is not rotated in the switching element 10. It remains P-polarized light. Accordingly, the P-polarized light has an S-polarized relationship with respect to the polarization plane 15a of the second polarization beam splitter 15, and is reflected by the polarization plane 15a and cannot reach the object 4 to be exposed.

  The plurality of laser beams Lb emitted from the pattern generator 6 are focused on the optical axis side by the second fθ lens 21 and then enter the mirror surface of the galvano mirror 22. Then, the light is reflected by the mirror surface of the galvanometer mirror 22 driven by the sawtooth wave having the driving frequency Fm, and the conveying direction of the exposed object 4 with the scanning width W on the exposed object 4 via the first fθ lens 8 ( The scanning is performed at a constant speed in a direction (arrow B, C direction) intersecting with the arrow A direction.

  As a result, as shown in FIG. 6, the switching element 10 is driven on / off at the switching frequency Fs while the laser beam Lb is scanned in the arrow B direction on the exposure object 4 being conveyed in the arrow A direction. The Therefore, one line of exposure is executed at the exposure pitch P2 in the direction crossing the conveying direction of the object 4 to be exposed. Further, while the laser beam Lb is scanned in the direction of the arrow C, all the switching elements 10 are turned off, so that the exposure during this time is stopped. When the first reciprocating scan of the laser beam Lb is completed, the irradiation position of the laser beam Lb is the exposure pitch P1 from the previous irradiation position because the exposure object 4 is transported at the speed V in the arrow A direction. The position is shifted backward. As a result, during the second reciprocating scan of the laser beam Lb, the exposure for the next one line is executed following the exposure for the previous one line. Thereafter, while the laser beam Lb is reciprocally scanned in the same manner, it is possible to uniformly expose the exposed area on the object to be exposed 4 without generating an unexposed portion. In this case, when the optical switch 9 is appropriately driven based on the CAD data, a dense exposure pattern can be formed on the object to be exposed 4. In the figure, a broken line indicates exposure of an adjacent exposure region by the adjacent laser beam Lb.

  If a polygon mirror is used instead of the galvanometer mirror 22, the backward scanning time T2 of the laser beam Lb shown in FIG. 4 can be shortened. Therefore, the scanning speed of the laser beam Lb can be increased to increase the conveyance speed of the object to be exposed 4. Thereby, the tact of an exposure process can be improved more.

FIG. 7 is a schematic block diagram that shows the second embodiment of the exposure apparatus of the present invention. Hereinafter, a different part from 1st Embodiment is demonstrated. In FIG. 7, the control means 3 is not shown.
In the second embodiment, an acousto-optic element (AOD) 30 as an optical scanning unit is disposed between the first fθ lens 8 and the transport unit 1. In FIG. 7, reference numeral 31 denotes a total reflection mirror.

  According to the second embodiment as described above, the object of the present invention can be achieved in which the scanning distance of the light beam that scans the object to be exposed 4 is shortened to shorten the tact time of the exposure process. Further, since the optical scanning means 7 is not a mechanically operated optical deflection mirror as in the first embodiment but an electronically operated acousto-optic element 30, there is little change over time and the laser beam Lb is stabilized for a long time. Can be scanned. Therefore, the reliability of the exposure apparatus can be improved.

FIG. 8 is a schematic block diagram that shows the third embodiment of the exposure apparatus of the present invention. Hereinafter, a different part from 1st and 2nd embodiment is demonstrated. In FIG. 8, the control means 3 is not shown.
In the third embodiment, an electro-optical element 32 is disposed as the optical scanning unit 7 at the object-side focal position of the first fθ lens 8. As shown in FIG. 9, the electro-optic element 32 has a pair of triangular electrodes each having a side 34 inclined with respect to an axis parallel to the optical axis of the opposing surface on the opposing surface of the square-block electro-optic crystal material 33. The configuration is provided with 35A and 35B.

  In this case, when the voltage applied between the pair of electrodes 35A and 35B is changed, the refractive index of the electro-optic crystal material 33 sandwiched between the pair of electrodes 35A and 35B changes. Therefore, the laser beam Lb incident on the electro-optical element 32 is refracted at the boundary surface corresponding to the inclined side 34 of the electrodes 35A and 35B. Therefore, the laser beam Lb is scanned in the directions of arrows B and C shown in FIG. 9 according to the change in the applied voltage. FIG. 9 shows a case where a plurality of electrodes 35A and 35B are provided corresponding to a plurality of laser beams Lb.

  According to the third embodiment as described above, the object of the present invention can be achieved in which the scanning distance of the light beam that scans the object to be exposed 4 is shortened to shorten the tact time of the exposure process. Further, since the laser beam Lb is scanned electronically rather than mechanically as in the first embodiment, the laser beam Lb is stabilized for a long time with little change in the optical scanning means 7 over time. Can be scanned. Therefore, the reliability of the exposure apparatus can be improved.

  In the third embodiment, the case where the electro-optic element 32 is disposed at the object side focal position of the first fθ lens 8 has been described. However, the electro-optic element 32 is disposed on the light emission side of the first fθ lens 8. Also good. However, the scanning angle of the laser beam Lb is smaller when the first fθ lens 8 is disposed at the object side focal position.

  In the above description, the case where the optical switch 9 uses an electro-optic crystal material has been described. However, the present invention is not limited to this, and the optical switch 9 is a micromirror that is driven on and off. May be. Therefore, the pattern generator 6 may be a micromirror array in which a plurality of micromirrors are arranged in a line at a constant arrangement pitch.

DESCRIPTION OF SYMBOLS 1 ... Conveyance means 3 ... Control means 6 ... Pattern generator 7 ... Optical scanning means 8 ... 1st f (theta) lens (f (theta) lens)
DESCRIPTION OF SYMBOLS 9 ... Optical switch 10 ... Switching element 11a, 11b ... Electrode 14 ... 1st polarizing beam splitter (polarizing element)
15 ... Second polarization beam splitter (polarization element)
21: Second fθ lens (another fθ lens)
22 ... Galvano mirror 30 ... Acousto-optic device (optical scanning means)
32 ... Electro-optical element (optical scanning means)
33 ... Electro-optic crystal material 35A, 35B ... Electrode

Claims (7)

Transport means for transporting the object to be exposed in a constant direction at a constant speed;
A plurality of laser beams in which laser beams expanded in one direction are arranged in a line at a constant arrangement pitch by a plurality of optical switches arranged in a line at a constant arrangement pitch in a direction intersecting the conveying direction of the object to be exposed. A pattern generator that divides and injects
Optical scanning means for simultaneously reciprocally scanning a region between the adjacent laser beams with the plurality of laser beams emitted from the pattern generator and irradiating the object to be exposed;
An fθ lens that condenses the laser beams to be reciprocated on the object to be exposed;
Control means for controlling on / off driving of the plurality of optical switches of the pattern generator;
An exposure apparatus comprising:   Each optical switch of the pattern generator is provided with electrodes on opposing surfaces parallel to the major axis of a prismatic switching element made of an electro-optic crystal material, and a pair of polarized lights on both end surfaces in the major axis direction of the switching element. 2. An exposure apparatus according to claim 1, wherein the elements are arranged in crossed Nicols.   The optical scanning means is a light deflection mirror disposed between the fθ lens and another fθ lens disposed between the pattern generator and the fθ lens so as to face the fθ lens in a mirror-symmetric manner. The exposure apparatus according to claim 1 or 2, wherein   4. The exposure apparatus according to claim 3, wherein the light deflection mirror is a galvanometer mirror.   4. The exposure apparatus according to claim 3, wherein the light deflection mirror is a polygon mirror.   The exposure apparatus according to claim 1, wherein the optical scanning unit is an acousto-optic element disposed between the fθ lens and the transport unit.   The optical scanning means is disposed between the fθ lens and another fθ lens disposed between the pattern generator and the fθ lens so as to face the fθ lens in a mirror-symmetric manner, and has a rectangular block-shaped electrical configuration. 3. The exposure apparatus according to claim 1, wherein the exposure apparatus is an electro-optical element provided with a triangular electrode having a side inclined with respect to the optical axis on the opposite surface of the optical crystal material.