Drawing apparatus

Abstract

To suppress fine vibrations during movement of a lens group by an autofocus mechanism.SOLUTION: An autofocus mechanism 5 of this drawing apparatus is provided with a sensor 51, a lens moving mechanism 52, and an auxiliary support 53. The sensor 51 measures a distance between a second lens group 452 and a substrate 9. The lens moving mechanism 52 supports the second lens group 452. The lens moving mechanism 52 vertically moves the second lens group 452 on the basis of an output from the sensor 51 to adjust the focus position of light emitted from a drawing head 41. The auxiliary support 53 continuously applies an upward force to the second lens group 452 to assist the lens moving mechanism 52 to support the second lens group 452. Thus, fine vibrations during rising / falling of the second lens group 452 can be suppressed.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a drawing apparatus that draws a pattern by irradiating a substrate with light. [Background technology]

[0002] Conventionally, there is known a direct imaging apparatus that irradiates a printed wiring board or the like (hereinafter also referred to as a "substrate") on a stage with modulated light and scans the irradiation area of ​​the light on the substrate to draw a pattern. In such a direct imaging apparatus, an autofocus mechanism is provided to deal with unevenness on the substrate surface.

[0003] For example, the autofocus mechanism provided in the drawing apparatus of Patent Document 1 includes a detector that detects fluctuations in the distance between the optical head and the substrate surface, a lifting mechanism that holds and raises and lowers the lens of the projection optical system, and a control unit that calculates the amount of lift of the lens based on the amount of fluctuation detected by the detector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-31502 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in a drawing device such as that disclosed in Patent Document 1, when the autofocus mechanism is in operation, there is a possibility that micro-vibrations may occur in the lens, etc. due to the driving load applied to the lifting mechanism, etc. In the future, if there is a demand for even finer patterns, there is a risk that the fluctuation in the line width of the pattern, etc., caused by the micro-vibrations of the lens, etc., may not be within the desired accuracy.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to suppress micro-vibrations that occur when a lens group is moved by an autofocus mechanism. [Means for solving the problem]

[0007] A first aspect of the present invention is a drawing apparatus for drawing a pattern by irradiating light onto a substrate, the drawing apparatus comprising: a stage for holding the substrate; a drawing head for irradiating modulated light onto the substrate; and a stage moving mechanism for moving the stage relative to the drawing head in a direction parallel to an upper surface of the substrate. The drawing head comprises an illumination optical system into which light emitted from a light source is incident; a light modulation unit for modulating the light guided by the illumination optical system; a projection optical system for guiding the light modulated by the light modulation unit to the substrate; and an autofocus mechanism for adjusting the focal position of the light emitted from the drawing head in accordance with a change in the distance between the projection optical system and the substrate. The projection optical system comprises a first lens group into which the light modulated by the light modulation unit is incident; and a second lens group for guiding the light guided by the first lens group to the substrate. The autofocus mechanism includes a sensor unit that measures the vertical distance between the second lens group and the substrate, a lens movement mechanism that supports the second lens group and adjusts the focal position of the light emitted from the drawing head by moving the second lens group vertically based on output from the sensor unit, and an auxiliary support unit that continuously applies an upward force to the second lens group to assist the lens movement mechanism in supporting the second lens group.

[0008] A second aspect of the present invention is the imaging device of the first aspect, wherein the imaging head further includes a frame supporting the lens moving mechanism, and the auxiliary support portion includes an elastic member connecting the frame and the second lens group in an elastically deformed state.

[0009] A third aspect of the present invention is the imaging device of the second aspect, wherein the elastic member is a coil spring extending in the vertical direction. The coil spring connects the frame and the second lens group in a vertically stretched state.

[0010] A fourth aspect of the present invention is the drawing device of any one of the first to third aspects, wherein the drawing head further includes a frame supporting the lens movement mechanism. The lens movement mechanism includes a guide rail fixed to the frame on one lateral side of the second lens group, extending in the vertical direction and guiding the vertical movement of the second lens group, and a bearing block fixed to the second lens group and moving along the guide rail while in contact with the guide rail. A force acting on the second lens group from the auxiliary support portion is directed upward toward the one lateral side.

[0011] A fifth aspect of the present invention is the imaging device of the fourth aspect, wherein the auxiliary support portion is disposed laterally on the one side of the second lens group and overlaps with the guide rail in a direction perpendicular to the up-down and lateral directions. Effect of the Invention

[0012] According to the present invention, it is possible to suppress minute vibrations that occur when the lens group is moved by the autofocus mechanism. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view showing a drawing device according to an embodiment; [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a control unit. [Diagram 3] FIG. 2 is a diagram illustrating a functional configuration of a control unit. [Figure 4] FIG. [Diagram 5] FIG. 2 is a vertical cross-sectional view showing a portion near an autofocus mechanism. [Figure 6] FIG. 4 is a front view showing a portion near the autofocus mechanism. [Figure 7] FIG. 2 is a plan view showing a portion near an autofocus mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] FIG. 1 is a perspective view showing a drawing apparatus 1 according to one embodiment of the present invention. The drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating a photosensitive material on a substrate 9 with spatially modulated light in a substantially beam shape and scanning the irradiated area of ​​the light on the substrate 9. In FIG. 1, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in FIG. 1, the X direction and the Y direction are horizontal directions perpendicular to each other, and the Z direction is a vertical direction (i.e., an up-down direction). The same applies to other figures.

[0015] The substrate 9 is, for example, a printed circuit board having a substantially rectangular flat plate shape. On the (+Z) main surface (hereinafter also referred to as "upper surface 91") of the substrate 9, a resist film formed of a photosensitive material is provided on a copper layer. In the drawing device 1, a circuit pattern is drawn (i.e., formed) on the resist film of the substrate 9. The type, shape, etc. of the substrate 9 may be changed in various ways.

[0016] The drawing apparatus 1 includes a stage 21, a stage moving mechanism 22, an alignment unit 3, a drawing unit 4, and a control unit 8. The stage 21 is a substantially rectangular flat member disposed below the alignment unit 3 and the drawing unit 4 (i.e., on the (-Z) side). The stage 21 includes a substrate holding unit 25 that holds a horizontal substrate 9 from below. The substrate holding unit 25 is, for example, a vacuum chuck that holds the lower surface of the substrate 9 by suction. The substrate holding unit 25 may have a structure other than a vacuum chuck, and may be, for example, a mechanical chuck. An upper surface 91 of the substrate 9 placed on the substrate holding unit 25 is substantially perpendicular to the Z direction and substantially parallel to the X and Y directions.

[0017] The stage moving mechanism 22 is a moving mechanism that moves the stage 21 relatively to the alignment unit 3 and the drawing unit 4 in a horizontal direction (i.e., a direction approximately parallel to the upper surface 91 of the substrate 9). The stage moving mechanism 22 is attached on the upper surface of the base 11 and is supported from below by the base 11. The stage moving mechanism 22 includes a first moving mechanism 23 and a second moving mechanism 24. The second moving mechanism 24 supports the stage 21 from below and linearly moves the stage 21 in the X direction along the guide rail. The first moving mechanism 23 supports the second moving mechanism 24 from below and linearly moves the stage 21 together with the second moving mechanism 24 in the Y direction along the guide rail. The driving sources of the first moving mechanism 23 and the second moving mechanism 24 are, for example, linear servo motors or motors attached to ball screws. The structures of the first moving mechanism 23 and the second moving mechanism 24 may be variously modified.

[0018] The drawing apparatus 1 may be provided with a stage rotation mechanism that rotates the stage 21 about a rotation axis extending in the Z direction. The drawing apparatus 1 may also be provided with a stage lifting mechanism that moves the stage 21 in the Z direction. For example, a servo motor can be used as the stage rotation mechanism. For example, a linear servo motor can be used as the stage lifting mechanism. The structures of the stage rotation mechanism and the stage lifting mechanism may be modified in various ways.

[0019] The alignment unit 3 includes a plurality of alignment cameras 31. In the example shown in FIG. 1, two alignment cameras 31 are arranged in the X direction, but only the alignment camera 31 on the (+X) side is shown. Each alignment camera 31 is supported above the stage 21 and the stage movement mechanism 22 by a support 27 that is provided across the stage 21 and the stage movement mechanism 22. The support 27 is, for example, a single metal member provided at one position in the Y direction. In the example shown in FIG. 1, the support 27 is a gate-shaped member (a so-called gantry) that is provided across the stage 21 and the stage movement mechanism 22, and is erected on the upper surface of the base 11.

[0020] 1, the two alignment cameras 31 are attached to the (+Y) side surface of the support unit 27. Of the two alignment cameras 31, for example, one alignment camera 31 is fixed to the support unit 27, and the other alignment camera 31 is movable in the X direction on the support unit 27. This makes it possible to change the distance in the X direction between the two alignment cameras 31. Note that the number of alignment cameras 31 in the alignment unit 3 may be one, or three or more.

[0021] Each alignment camera 31 captures an image of an alignment mark (not shown) provided in advance on the upper surface 91 of the substrate 9. In the drawing device 1, alignment of the substrate 9 (i.e., correction of the relative position of the substrate 9 with respect to the drawing head 41) is performed based on the image of the alignment mark acquired by the alignment camera 31.

[0022] The drawing unit 4 includes a plurality of drawing heads 41 (six in the example shown in FIG. 1) arranged in the X direction. The plurality of drawing heads 41 have approximately the same structure. Each drawing head 41 includes an optical modulator that irradiates modulated (i.e., spatially modulated) light downward. Each drawing head 41 is supported above the stage 21 and the stage moving mechanism 22 by the above-mentioned support unit 27. In the example shown in FIG. 1, the six drawing heads 41 are attached to the (-Y) side surface of the support unit 27. Note that the above-mentioned alignment camera 31 may be supported by a support unit different from the support unit 27 to which the drawing heads 41 are attached.

[0023] In the example shown in FIG. 1, the six drawing heads 41 are arranged in a substantially straight line substantially parallel to the X direction. The positions of the six drawing heads 41 in the Y direction and the Z direction are substantially the same. In FIG. 1, a sensor unit 51 (described later) of each drawing head 41 is omitted. Note that the multiple drawing heads 41 do not necessarily need to be arranged in a straight line, and may be arranged, for example, in a staggered manner. When the drawing heads 41 are arranged in a staggered manner, for example, the multiple drawing heads 41 are arranged substantially parallel to the X direction at a first position in the Y direction, and at a second position adjacent to the (-Y) side of the first position, a drawing head 41 is arranged between each of the multiple drawing heads 41 in the X direction. Also, in the drawing unit 4, the number of drawing heads 41 may be one or may be two or more.

[0024] In the drawing device 1, pattern drawing on the substrate 9 is performed by a so-called multi-pass method. Specifically, while modulated light from the multiple drawing heads 41 of the drawing unit 4 is irradiated onto the upper surface 91 of the substrate 9, the first moving mechanism 23 of the stage moving mechanism 22 moves the substrate 9 in the Y direction to pass under the drawing heads 41. As a result, the irradiation area of ​​the light from the multiple drawing heads 41 is scanned in the Y direction on the substrate 9, and drawing on the substrate 9 is performed. Next, the second moving mechanism 24 moves the substrate 9 stepwise by a predetermined distance in the X direction. Then, the first moving mechanism 23 moves the substrate 9 in the Y direction, and the drawing heads 41 irradiate the substrate 9 with light in parallel with the movement again, thereby performing drawing on the substrate 9. In the drawing device 1, the irradiation of light on the substrate 9 moving in the Y direction and the step movement of the substrate 9 in the X direction are alternately performed, thereby performing drawing on the substrate 9.

[0025] In the following description, the Y direction is also referred to as the "main scanning direction" or "scanning direction", and the X direction is also referred to as the "sub-scanning direction". The main scanning direction and the sub-scanning direction are directions that are approximately parallel to the upper surface 91 of the substrate 9. In the stage movement mechanism 22, the first movement mechanism 23 is a main scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the main scanning direction. The second movement mechanism 24 is a sub-scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the sub-scanning direction.

[0026] In the drawing apparatus 1, drawing on the substrate 9 may be performed by a single pass method (also called a one-pass method) in which drawing of a pattern on the substrate 9 is completed by moving the substrate 9 relatively to the drawing head 41 only once in the Y direction. In this case, sub-scanning of the substrate 9 by the second moving mechanism 24 (i.e., step movement in the X direction) is not performed when drawing the pattern. In other words, the stage moving mechanism 22 is a scanning mechanism that moves the stage 21 at least in the scanning direction relative to the drawing head 41.

[0027] The control unit 8 controls the configuration of the stage 21, the stage moving mechanism 22, the alignment unit 3, the drawing unit 4, etc. FIG. 2 is a diagram showing the configuration of the control unit 8. The control unit 8 has a configuration of a general computer system including a CPU 81, a ROM 82, a RAM 83, a fixed disk 84, a display 85, an input unit 86, a reading device 87, a communication unit 88, and a bus 80. The CPU 81 performs various arithmetic processing. The ROM 82 stores basic programs. The RAM 83 stores various information. The fixed disk 84 stores information. The display 85 is a display unit that displays various information such as images. The input unit 86 includes a keyboard 86a and a mouse 86b that receive input from an operator.

[0028] The reading device 87 reads information from a computer-readable recording medium 811 such as an optical disk, a magnetic disk, a magneto-optical disk, or a memory card. The display 85, the keyboard 86a, the mouse 86b, and the reading device 87 are connected to the bus 80 via an interface I / F. The communication unit 88 transmits and receives signals to and from components of the drawing device 1 other than the control unit 8, and external devices, etc. The bus 80 is a signal circuit that connects the CPU 81, the ROM 82, the RAM 83, the fixed disk 84, the display 85, the input unit 86, the reading device 87, and the communication unit 88.

[0029] In control unit 8, program 812 is read in advance from recording medium 811 via reading device 87 and stored in fixed disk 84. Program 812 may be stored in fixed disk 84 via a network. CPU 81 functions as a calculation unit that executes calculation processing while using RAM 83 and fixed disk 84 in accordance with program 812. Other configurations that function as a calculation unit other than CPU 81 may be employed.

[0030] FIG. 3 is a diagram showing a functional configuration realized by the control unit 8 executing arithmetic processing and the like according to the program 812. These functional configurations include a storage unit 801, a drawing control unit 802, and a lens movement control unit 803. All or part of these functions may be realized by a dedicated electric circuit. Also, these functions may be realized by a plurality of computers. Among the functional configurations shown in FIG. 3, the drawing control unit 802 and the lens movement control unit 803 are realized by the CPU 81, the ROM 82, the RAM 83, the fixed disk 84, and their peripheral configurations. Also, the storage unit 801 is mainly realized by the RAM 83 and the fixed disk 84.

[0031] FIG. 4 is an enlarged side view of one drawing head 41 from the (+X) side. The other drawing heads 41 have the same structure as the drawing head 41 shown in FIG. 4. The drawing head 41 includes a light source unit 42, an illumination optical system 43, a light modulation unit 44, a projection optical system 45, a drawing head cover 46, a frame 47, and an autofocus mechanism 5. The light source unit 42, the illumination optical system 43, the light modulation unit 44, the projection optical system 45, and the frame 47 are housed inside the drawing head cover 46. A part of the autofocus mechanism 5 is also housed inside the drawing head cover 46. In FIG. 4, in order to facilitate understanding of the drawing, a cross section of the drawing head cover 46 is shown by a dashed line, and the internal structure of the drawing head cover 46 is shown by a solid line. In addition, FIG. 4 also shows a support unit 27.

[0032] In the example shown in Fig. 4, the drawing head cover 46 is a member that is substantially L-shaped in a side view. The light source unit 42 is disposed inside the drawing head cover 46 at the end on the (+Y) side of the upper part of the drawing head 41. The light source unit 42 includes a light source 421 such as an LED (Light Emitting Diode) or an LD (Laser Diode). Light emitted from the light source 421 enters the illumination optical system 43 along a predetermined optical axis J1 of the drawing head 41. In Fig. 4, the optical axis J1 is depicted by a dashed line.

[0033] The illumination optical system 43 is disposed inside the drawing head cover 46 on the (-Y) side of the light source unit 42, above the drawing head 41. The illumination optical system 43 extends approximately parallel to the Y direction. The illumination optical system 43 includes optical elements such as a plurality of lenses arranged approximately parallel to the Y direction. In FIG. 4, the plurality of lenses are not shown, and a lens barrel in which the plurality of lenses are housed is shown. The illumination optical system 43 guides light incident from the light source 421 to the light modulation unit 44. In the example shown in FIG. 4, the light that has passed through the illumination optical system 43 is incident on the light modulation unit 44 via mirrors 431 and 432.

[0034] The light modulation unit 44 is disposed inside the drawing head cover 46 at the end on the (-Y) side of the upper part of the drawing head 41. The light modulation unit 44 is located on the (-Y) side of the illumination optical system 43. The light modulation unit 44 includes a spatial light modulator that modulates light. The spatial light modulator is, for example, a DMD (Digital Micromirror Device) in which a plurality of micromirrors are arranged two-dimensionally. Note that the light modulation unit 44 may include a spatial light modulator other than a DMD. The light modulation unit 44 modulates the light guided by the illumination optical system 43 and guides it to the projection optical system 45.

[0035] The projection optical system 45 is disposed inside the drawing head cover 46 at the end of the drawing head 41 on the (-Y) side, on the (-Z) side (i.e., below) of the light modulation unit 44. The projection optical system 45 extends approximately parallel to the Z direction. The projection optical system 45 includes optical elements such as a plurality of lenses arranged approximately parallel to the Z direction. In FIG. 4, the lenses are not shown, but a lens barrel in which the lenses are housed is shown. The projection optical system 45 guides the light modulated by the light modulation unit 44 to the upper surface 91 of the substrate 9 (see FIG. 1).

[0036] The projection optical system 45 includes a first lens group 451 and a second lens group 452. The first lens group 451 includes optical elements such as a plurality of lenses arranged substantially parallel to the Z direction. The second lens group 452 includes an optical element such as one lens, or a plurality of optical elements such as lenses arranged substantially parallel to the Z direction. In FIG. 4, the illustration of the plurality of lenses, etc. is omitted for each of the first lens group 451 and the second lens group 452, and a lens barrel, etc. in which the plurality of lenses, etc. are accommodated is illustrated. The first lens group 451 and the second lens group 452 are arranged substantially parallel to the Z direction. The first lens group 451 is located on the (+Z) side of the second lens group 452.

[0037] In the projection optical system 45, the light modulated by the light modulation unit 44 enters the first lens group 451 and is guided by the first lens group 451 to the second lens group 452. The second lens group 452 guides the light guided by the first lens group 451 to the upper surface 91 of the substrate 9.

[0038] The first lens group 451 and the second lens group 452 are attached to a side surface on the (-Y) side of a frame 47, which is a substantially rectangular prism-shaped member extending in the Z direction. The first lens group 451 and the second lens group 452 are attached to the frame 47 so as to be movable in the Z direction. The first lens group 451 is raised and lowered when changing the magnification of an image formed on the substrate 9, and is not raised and lowered while a pattern is being drawn on the substrate 9. The second lens group 452 is raised and lowered by the autofocus mechanism 5 while a pattern is being drawn on the substrate 9. The frame 47 is a support member that supports the first lens group 451 and the second lens group 452. The frame 47 is fixed, for example, to the inside of the drawing head cover 46, and is indirectly supported by the support portion 27 via the drawing head cover 46. The frame 47 may be a part of the drawing head cover 46.

[0039] In the imaging head 41, the second lens group 452 in the projection optical system 45 is moved in the Z direction, whereby the focal position of the light emitted from the imaging head 41 toward the substrate 9 is adjusted in the Z direction. The focal position is a position where the light emitted from the imaging head 41 toward the substrate 9 is collected on the (-Z) side of the imaging head 41. In other words, the focal position is a position where the light that has passed through the second lens group 452 from the (+Z) side toward the (-Z) side is collected on the (-Z) side of the second lens group 452. In further other words, the focal position is a position where an image of the micromirror of the DMD of the light modulation section 44 is formed on the (-Z) side of the second lens group 452.

[0040] In the projection optical system 45, the first lens group 451 is housed inside the imaging head cover 46. The second lens group 452 is also housed inside the imaging head cover 46. The lower end of the imaging head cover 46 is open. The lower end of the second lens group 452 (i.e., the lower end of the projection optical system 45) may protrude downward from the lower end opening of the imaging head cover 46.

[0041] The autofocus mechanism 5 is disposed near the second lens group 452 of the projection optical system 45. The autofocus mechanism 5 adjusts the focal position of the light emitted from the drawing head 41 toward the substrate 9 in the Z direction by moving (i.e., raising and lowering) the second lens group 452 in the Z direction in accordance with the change in the distance between the projection optical system 45 and the substrate 9.

[0042] FIG. 5 is an enlarged longitudinal sectional view of the drawing head 41 shown in FIG. 4, showing a portion near the second lens group 452 of the projection optical system 45 and the autofocus mechanism 5. In FIG. 5, a portion of the configuration is shown from the side. In FIG. 5, the configuration behind the cross section is also shown by thin lines. FIG. 6 is a front view of the portion near the second lens group 452 and the autofocus mechanism 5 as seen from the (-Y) side. FIG. 7 is a plan view of the portion near the second lens group 452 and the autofocus mechanism 5 as seen from the (+Z) side. In FIG. 7, the first lens group 451 is omitted, and the frame 47 is drawn in cross section at the position of an opening 471 described later.

[0043] The autofocus mechanism 5 includes a sensor unit 51, a lens moving mechanism 52, and an auxiliary support unit 53. The sensor unit 51 is attached to the second lens group 452 of the projection optical system 45. In detail, the sensor unit 51 is fixed to the lower end of the lens barrel of the second lens group 452 (i.e., the end on the (-Z) side). The sensor unit 51 measures the distance in the Z direction between the lower end of the second lens group 452 and the upper surface 91 of the substrate 9 on the stage 21 (see FIG. 1) (hereinafter referred to as the "projection distance").

[0044] The sensor unit 51 includes a light emitting unit 511, a light receiving unit 512, and a sensor support unit 513. The sensor support unit 513 is, for example, a substantially cylindrical member extending substantially parallel to the Z direction. The sensor support unit 513 is located on the (-Z) side of the second lens group 452 outside the drawing head cover 46, and is fixed to the lower end of the lens barrel of the second lens group 452. In the example shown in FIG. 5, the light emitting unit 511 is fixed to the end of the (+Y) side of the sensor support unit 513 at the end of the (-Z) side of the sensor support unit 513. The light receiving unit 512 is fixed to the end of the (-Y) side of the sensor support unit 513 at the end of the (-Z) side of the sensor support unit 513. The light emitted from the light emitting unit 511 to the (-Y) side and the (-Z) side is reflected by the upper surface 91 of the substrate 9 and received by the light receiving unit 512. The light receiving unit 512 is, for example, a line sensor. In the sensor unit 51, the projection distance is calculated based on the light receiving position of the light reflected from the substrate 9 in the light receiving unit 512.

[0045] The lens movement mechanism 52 is attached to and supported by the frame 47. The lens movement mechanism 52 connects the second lens group 452 and the frame 47. The lens movement mechanism 52 supports the second lens group 452 and moves the second lens group 452 in the Z direction. The lens movement mechanism 52 includes a drive unit 521, a guide rail 522, a bearing block 523, and a lens support unit 524.

[0046] Guide rail 522 is fixed to a side surface on the (-Y) side of frame 47 on the (+Y) side of second lens group 452. If the Y direction is called the "horizontal direction", guide rail 522 is disposed between second lens group 452 and frame 47 in the lateral direction. Guide rail 522 includes two rails aligned in the X direction. The two rails extend approximately parallel to the Z direction.

[0047] The bearing block 523 is a bearing member that is connected to the guide rail 522 from the (-Y) side and is movable in the Z direction along the guide rail 522. In the example shown in Figs. 5 to 7, two bearing blocks 523 are respectively connected to two rails of the guide rail 522. Each bearing block 523 is, for example, a substantially rectangular parallelepiped or substantially flat member. Each bearing block 523 moves smoothly in the Z direction along the guide rail 522 while contacting the guide rail 522.

[0048] The lens support portion 524 is a member that is fixed to the bearing block 523 and supports the second lens group 452. In the example shown in FIG. 5 to FIG. 7, the lens support portion 524 includes a first portion 525, a second portion 526, and a third portion 527. The first portion 525 and the second portion 526 are a continuous member disposed on the (-Y) side of the bearing block 523. The first portion 525 and the second portion 526 are substantially L-shaped in side view. The first portion 525 is a substantially flat portion that extends substantially parallel to the Z direction and is substantially perpendicular to the Y direction. Two bearing blocks 523 are fixed to the side surface on the (+Y) side of the first portion 525.

[0049] The second portion 526 protrudes from the end of the first portion 525 on the (-Z) side toward the (-Y) side. The second portion 526 is a generally flat portion extending generally parallel to the Y direction and generally perpendicular to the Z direction. The second portion 526 is provided with a through hole penetrating in the Z direction. The lens barrel of the second lens group 452 is inserted into the through hole, whereby the second lens group 452 is supported by the lens support portion 524. That is, the second lens group 452 is indirectly fixed to the bearing block 523 via the second portion 526 and the first portion 525 of the lens support portion 524.

[0050] The third portion 527 is a portion that protrudes in the (+Y) direction from the (+Y) side surface of the first portion 525 at approximately the center of the first portion 525 in the X and Z directions. The third portion 527 is a substantially columnar or cylindrical portion that extends approximately parallel to the Y direction. The third portion 527 is inserted into the frame 47 from an opening 471 provided between two rails of the guide rail 522 on the (-Y) side surface of the frame 47. The (+Y) end of the third portion 527 is connected to the drive unit 521 inside the frame 47. The weights of the lens support portion 524 and the second lens group 452 are mainly supported by the drive unit 521. Note that the bearing block 523 is connected to the guide rail 522 so that friction between the bearing block 523 and the guide rail 522 is minimized, and therefore the guide rail 522 hardly supports the weights of the lens support portion 524 and the second lens group 452.

[0051] The driving unit 521 extends in the Z direction inside the frame 47 and is fixed to the frame 47. In other words, the driving unit 521 is supported by the support unit 27 via the frame 47. The driving unit 521 is, for example, a combination of an electric motor and a ball screw. The end of the (+Y) side of the third part 527 described above is fixed to a movable element movable in the Z direction in the driving unit 521. When the movable element is moved in the Z direction in the driving unit 521, the lens support unit 524 fixed to the movable element, and the second lens group 452 and the bearing block 523 fixed to the lens support unit 524 are moved in the Z direction while being guided by the guide rail 522. The driving unit 521 may be variously modified, such as a linear servo motor or an air cylinder.

[0052] In the drawing apparatus 1 shown in FIG. 1, when the above-mentioned pattern drawing is performed on the substrate 9, the drawing control unit 802 controls the light modulation unit 44 and the stage moving mechanism 22 based on drawing data pre-stored in the memory unit 801 (see FIG. 3) of the control unit 8, so that modulated light is irradiated onto the upper surface 91 of the substrate 9 moving in the Y direction to draw the pattern.

[0053] In the drawing device 1, while the above pattern is being drawn on the substrate 9, the sensor unit 51 shown in FIGS. 5 to 7 continuously measures the above-mentioned projection distance. The projection distance measured by the sensor unit 51 is output to the lens movement control unit 803. The lens movement control unit 803 controls the lens movement mechanism 52 based on the output from the sensor unit 51. As a result, the position of the second lens group 452 in the Z direction is adjusted by the lens movement mechanism 52, and the focal position of the light emitted from the drawing head 41 toward the substrate 9 is adjusted in the Z direction to be aligned with the upper surface 91 of the substrate 9. As a result, even if the substrate 9 is deformed, such as warped, or if the upper surface 91 of the substrate 9 has unevenness, the focal position can be aligned with the upper surface 91 of the substrate 9, thereby achieving highly accurate drawing.

[0054] The auxiliary support section 53 shown in FIGS. 5 to 7 is disposed on the (+Z) side of the lens support section 524 on the (+Y) side of the second lens group 452, and assists the lens moving mechanism 52 in supporting the second lens group 452 (specifically, the driver 521 in supporting the lens support section 524 and the second lens group 452). The auxiliary support section 53 includes a coil spring 533 that is an elastic member extending along the Z direction between the two rails of the guide rail 522. In the example shown in FIG. 5, the coil spring 533 extends substantially parallel to the Z direction, and partially overlaps with the guide rail 522 in the X direction (i.e., in a side view). Specifically, a portion of the coil spring 533 on the (+Y) side overlaps with the guide rail 522 in a side view. The entire coil spring 533 may overlap with the guide rail 522 in the X direction.

[0055] A lower end of the coil spring 533 is connected to a locking metal fitting that protrudes from an upper end of the first part 525 of the lens support part 524 to the (+Y) side (i.e., protrudes toward the frame 47). In other words, a lower end of the auxiliary support part 53 is indirectly connected to the second lens group 452 via the locking metal fitting and the lens support part 524. An upper end of the coil spring 533 is connected to a locking metal fitting that protrudes from a side surface on the (-Y) side of the frame 47 to the (-Y) side (i.e., protrudes toward the second lens group 452). In other words, an upper end of the auxiliary support part 53 is indirectly connected to the frame 47 via the locking metal fitting.

[0056] Coil spring 533 is connected to frame 47 and lens support portion 524 in a state where it is stretched in the Z direction. In other words, auxiliary support portion 53 is connected to frame 47 and second lens group 452 via lens support portion 524 in a state where it is elastically deformed in the vertical direction. Furthermore, coil spring 533 is always in a stretched state regardless of where lens support portion 524 and second lens group 452 are located within the movable range in the Z direction.

[0057] Therefore, regardless of the positions of the lens support unit 524 and the second lens group 452 in the Z direction, the restoring force of the auxiliary support unit 53 acts as a force that pulls the lens support unit 524 and the second lens group 452 up toward the (+Z) side. That is, an upward force is continuously applied to the lens support unit 524 and the second lens group 452 by the auxiliary support unit 53, and the weight of the lens support unit 524 and the second lens group 452 applied to the drive unit 521 is reduced. As a result, when the drive unit 521 moves the lens support unit 524 and the second lens group 452 in the up-down direction, the downward load (i.e., the drive load) applied to the drive unit 521 by the weight of the lens support unit 524 and the second lens group 452 is reduced. This suppresses vibrations in the drive unit 521 and the second lens group 452 when the second lens group 452 is raised or lowered (particularly when it is raised), and allows the second lens group 452 to be smoothly raised or lowered. The vibrations are relatively small and are hereinafter also referred to as "micro vibrations."

[0058] In the following description, the upper end of the first portion 525 of the lens support portion 524 (i.e., a portion of the lens support portion 524 on which the restoring force of the auxiliary support portion 53 acts) is also referred to as the "first connection portion 531". Also, a portion of the frame 47 on which the restoring force of the auxiliary support portion 53 acts is also referred to as the "second connection portion 532". In the example shown in FIG. 5, the first connection portion 531 is located on the (+Z) side of the contact portion between the bearing block 523 and the guide rail 522. Also, the second connection portion 532 is located on the (+Z) side and the (+Y) side of the first connection portion 531. Therefore, the force acting from the auxiliary support portion 53 to the lens support portion 524 and the second lens group 452 is directed to the (+Z) side and the (+Y) side. Also, a moment in the clockwise direction in FIG. 5 due to the force (hereinafter, also referred to as the "auxiliary moment") acts on the contact portion of the guide rail 522 with the bearing block 523.

[0059] In the drawing head 41, as described above, the bearing block 523 is connected to the guide rail 522 from the (-Y) side, and the lens support portion 524 and the second lens group 452 are fixed to the side surface of the bearing block 523 on the (-Y) side. Therefore, a moment in the counterclockwise direction in FIG. 5 due to the weight of the second lens group 452 and the lens support portion 524 (hereinafter, also referred to as "weight moment") acts on the contact portion of the guide rail 522 with the bearing block 523. The weight moment due to the second lens group 452 and the lens support portion 524 is reduced by the auxiliary moment due to the auxiliary support portion 53. Therefore, when the lens support portion 524 and the second lens group 452 move in the vertical direction, friction at the contact portion between the bearing block 523 and the guide rail 522 is reduced. As a result, when the second lens group 452 moves up and down, the occurrence of micro-vibrations in the bearing block 523, the second lens group 452, and the like is further suppressed, and the second lens group 452 moves up and down even more smoothly.

[0060] As described above, the drawing device 1, which draws a pattern by irradiating light onto the substrate 9, includes the stage 21, the drawing head 41, and the stage moving mechanism 22. The stage 21 holds the substrate 9. The drawing head 41 irradiates the substrate 9 with modulated light. The stage moving mechanism 22 moves the stage 21 relative to the drawing head 41 in a direction parallel to the upper surface 91 of the substrate 9. The drawing head 41 includes an illumination optical system 43, a light modulation unit 44, a projection optical system 45, and an autofocus mechanism 5. The illumination optical system 43 receives light emitted from the light source unit 42. The light modulation unit 44 modulates the light guided by the illumination optical system 43. The projection optical system 45 guides the light modulated by the light modulation unit 44 to the substrate 9. The autofocus mechanism 5 adjusts the focus position of the light emitted from the drawing head 41 in accordance with a change in the distance between the projection optical system 45 and the substrate 9.

[0061] The projection optical system 45 includes a first lens group 451 and a second lens group 452. The first lens group 451 receives light modulated by the light modulation unit 44. The second lens group 452 guides the light guided by the first lens group 451 to the substrate 9. The autofocus mechanism 5 includes a sensor unit 51, a lens movement mechanism 52, and an auxiliary support unit 53. The sensor unit 51 measures the vertical distance (i.e., the projection distance) between the second lens group 452 and the substrate 9. The lens movement mechanism 52 supports the second lens group 452. The lens movement mechanism 52 adjusts the focal position of the light emitted from the drawing head 41 by moving the second lens group 452 in the vertical direction (Z direction in the above example) based on the output from the sensor unit 51. The auxiliary support unit 53 continuously exerts an upward force on the second lens group 452 to assist the lens movement mechanism 52 in supporting the second lens group 452.

[0062] This, as described above, makes it possible to reduce the drive load generated in the lens moving mechanism 52 when the second lens group 452 is raised and lowered. As a result, it is possible to suppress micro-vibrations when the second lens group 452 is raised and lowered, and to suppress deterioration in drawing accuracy caused by the micro-vibrations.

[0063] As described above, it is preferable that the imaging head 41 further includes the frame 47 that supports the lens moving mechanism 52. It is also preferable that the auxiliary support part 53 includes an elastic member that connects the frame 47 and the second lens group 452 in an elastically deformed state. This allows the structure of the auxiliary support part 53 to be simplified. That is, in the imaging device 1, the driving load acting on the lens moving mechanism 52 can be reduced with a simple structure.

[0064] As described above, the elastic member is preferably the coil spring 533 extending in the vertical direction. Moreover, the coil spring 533 preferably connects the frame 47 and the second lens group 452 in a state of being stretched in the vertical direction. This allows the structure of the auxiliary support part 53 to be further simplified. That is, the driving load acting on the lens moving mechanism 52 can be reduced with an even simpler structure.

[0065] As described above, the drawing head 41 preferably further includes a frame 47 that supports the lens moving mechanism 52. The lens moving mechanism 52 preferably includes a guide rail 522 and a bearing block 523. The guide rail 522 is fixed to the frame 47 on one lateral side (the (+Y) side in the above example) of the second lens group 452 and extends in the vertical direction. The guide rail 522 guides the vertical movement of the second lens group 452. The bearing block 523 is fixed to the second lens group 452 and moves along the guide rail 522 while contacting the guide rail 522. Preferably, the force acting on the second lens group 452 from the auxiliary support portion 53 is directed upward and toward the one lateral side. Thereby, as described above, the weight moment acting on the guide rail 522 due to the weight of the second lens group 452 and the like can be reduced by the auxiliary moment from the auxiliary support portion 53. As a result, micro-vibrations occurring when the second lens group 452 is raised and lowered can be further suppressed, and deterioration in drawing accuracy caused by the micro-vibrations can be further suppressed.

[0066] As described above, it is preferable that the auxiliary support portion 53 is disposed on the one side in the horizontal direction from the second lens group 452 and overlaps with the guide rail 522 in the direction perpendicular to the up-down direction and the horizontal direction (the X direction in the above example). This makes it possible to increase the auxiliary moment by the auxiliary support portion 53, and further reduce the weight moment acting on the guide rail 522 due to the weight of the second lens group 452 and the like. As a result, it is possible to further suppress the micro-vibrations occurring when the second lens group 452 is raised and lowered, and further suppress the deterioration of the drawing accuracy caused by the micro-vibrations. In addition, it is also possible to miniaturize the autofocus mechanism 5, and thus the drawing head 41 and the drawing device 1.

[0067] The above-described drawing device 1 can be modified in various ways.

[0068] For example, the position of the coil spring 533 of the auxiliary support portion 53 is not limited to the above example and may be changed in various ways. For example, the coil spring 533 does not necessarily have to overlap the guide rail 522 in a side view, and may be disposed on the (-Y) side of the guide rail 522. In addition, the coil spring 533 does not necessarily have to be disposed so as to extend substantially parallel to the Z direction, and may be disposed so as to be inclined with respect to the Z direction.

[0069] In the above example, the lower end of coil spring 533 is connected to the upper end of first portion 525 of lens support portion 524, but may be connected to another position on lens support portion 524. In addition, the lower end of coil spring 533 does not necessarily need to be indirectly connected to second lens group 452 via lens support portion 524, and may be directly connected to second lens group 452.

[0070] The force acting from the auxiliary support part 53 to the second lens group 452 does not necessarily have to be directed toward the (+Z) side and the (+Y) side, and may be changed in various ways. For example, the force acting from the auxiliary support part 53 to the second lens group 452 may be directed toward the (+Z) side substantially parallel to the Z direction.

[0071] In the auxiliary support portion 53, instead of the coil spring 533, other elastic members such as leaf springs or flat rubber may be connected in a stretched state to the frame 47 and the second lens group 452. The material of the elastic member may be metal or a material other than metal (for example, resin, etc.).

[0072] The elastic member provided in auxiliary support portion 53 does not necessarily need to be connected to second lens group 452 in a tensile state to pull up second lens group 452, but may be connected to second lens group 452 in a compressed state to push up second lens group 452. For example, inside frame 47, a coil spring compressed in the vertical direction may be connected between the lower end of frame 47 and third portion 527 of lens support portion 524, and third portion 527 may be pushed up by the coil spring, thereby assisting support of second lens group 452 by drive portion 521.

[0073] The bearing block 523 does not necessarily have to be indirectly fixed to the second lens group 452 via the lens support portion 524, and may be directly fixed to the second lens group 452. In the drawing head 41, the lens support portion 524 may be omitted.

[0074] The shape of the drawing head cover 46 may be changed in various ways, and for example, the drawing head cover 46 may be a member extending approximately parallel to the Z direction. In this case, the illumination optical system 43 and the light source unit 42 are disposed on the (+Z) side of the light modulation unit 44, for example.

[0075] In the example shown in FIG. 4, one light source 421 is drawn in the light source unit 42, but the number of light sources 421 provided in the light source unit 42 may be multiple. For example, multiple light sources 421 emitting light of different wavelengths may be provided in the light source unit 42. In this case, when drawing a pattern on the substrate 9, one or more light sources 421 are selected and used from the multiple light sources 421 according to the type of photosensitive material on the substrate 9, etc. Note that the light source 421 provided in the light source unit 42 is not limited to an LED and an LD, and various types can be used. In addition, the light source unit 42 may be provided outside the drawing head 41. In this case, the light emitted from the light source unit 42 is guided to the drawing head 41 via an optical fiber or the like.

[0076] The stage moving mechanism 22 does not necessarily need to move the stage 21, but may move the multiple drawing heads 41 in a direction parallel to the upper surface 91 of the substrate 9 above the fixed stage 21, for example.

[0077] The substrate 9 on which drawing is performed by the drawing apparatus 1 is not necessarily limited to a printed wiring board. The drawing apparatus 1 may draw a circuit pattern on, for example, a semiconductor substrate, a glass substrate for a flat panel display device such as a liquid crystal display device or a plasma display device, a glass substrate for a photomask, a substrate for a solar panel, or the like.

[0078] The configurations in the above-described embodiment and each of the modified examples may be combined as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0079] 1 Drawing device 5 Autofocus mechanism 9 Substrate 21 Stage 22 Stage movement mechanism 41 Drawing head 43 Illumination optical system 44 Optical modulation section 45 Projection optical system 47 Frames 51 Sensor section 52 Lens movement mechanism 53 Auxiliary support part 91 (Platform) Top 421 Light source 451 First lens group 452 Second lens group 522 Guide Rail 523 Bearing Block 533 Coil Spring

Claims

1. A drawing apparatus that draws a pattern by irradiating a substrate with light, A stage for holding the substrate; a drawing head that irradiates the substrate with modulated light; a stage moving mechanism that moves the stage relative to the drawing head in a direction parallel to an upper surface of the substrate; Equipped with The imaging head includes: an illumination optical system into which light emitted from a light source is incident; a light modulation unit that modulates the light guided by the illumination optical system; a projection optical system that guides the light modulated by the light modulation unit to a substrate; an autofocus mechanism for adjusting a focal position of light emitted from the drawing head in accordance with a change in the distance between the projection optical system and the substrate; Equipped with The projection optical system includes: a first lens group onto which the light modulated by the light modulation unit is incident; a second lens group that guides the light guided by the first lens group to the substrate; Equipped with The autofocus mechanism includes: a sensor unit for measuring a distance between the second lens group and the substrate in a vertical direction; a lens moving mechanism that supports the second lens group and moves the second lens group in a vertical direction based on an output from the sensor unit to adjust the focal position of the light emitted from the imaging head; an auxiliary support portion that continuously applies an upward force to the second lens group to assist the lens moving mechanism in supporting the second lens group; A drawing device comprising:

2. The drawing device according to claim 1 , The imaging head further includes a frame supporting the lens moving mechanism, The auxiliary support portion includes an elastic member that connects the frame and the second lens group in an elastically deformed state.

3. The drawing device according to claim 2, The elastic member is a coil spring extending in the up-down direction, The coil spring connects the frame and the second lens group in a vertically stretched state.

4. 4. The drawing device according to claim 1, The imaging head further includes a frame supporting the lens moving mechanism, The lens moving mechanism includes: a guide rail fixed to the frame on one lateral side of the second lens group, extending in a vertical direction and guiding a vertical movement of the second lens group; a bearing block fixed to the second lens group and moving along the guide rail while being in contact with the guide rail; Equipped with An imaging apparatus in which the force acting on the second lens group from the auxiliary support portion is directed upward and laterally toward the one side.

5. The drawing device according to claim 4, the auxiliary support portion is disposed on the one side of the second lens group in the lateral direction and overlaps with the guide rail in a direction perpendicular to the up-down and lateral directions.

Images