Light irradiation device and drawing device

Abstract

To appropriately irradiate an irradiation surface with light of desired intensity while avoiding enlarging of a light irradiation apparatus.SOLUTION: A light irradiation apparatus 31 comprises: a light source part 4 which emits light to a prescribed position; and an irradiation optical system 5 which is arranged at the prescribed position, and leads the light to an irradiation surface 320 along an optical axis J1. The irradiation optical system 5 comprises: a variable attenuator 66 which is arranged at a position at which light is divergent light or convergent light when seen along one direction perpendicular to the optical axis J1, and varies the intensity of the light by changing an angle for translucent plates 661, 662 with respect to the optical axis J1, the translucent plates being a flat plate, in which normal lines of both principal planes are perpendicular to the one direction; and a focus lens mechanism 67 which arranges a light condensing position on the irradiation surface 320 when seen along the one direction by moving a lens 671 arranged between the variable attenuator 66 and the irradiation surface 320 along the optical axis J1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a light irradiation device and a drawing device. [Background technology]

[0002] Conventionally, a semiconductor laser (LD) is used as a light source of a drawing device. For example, the light irradiation device of Patent Document 1 includes a light source unit that emits laser light from multiple LDs toward a predetermined position, and an irradiation optical system that is arranged at the predetermined position and guides the laser light from the light source unit along the optical axis to an irradiation surface. In the irradiation optical system, the light incident from the multiple LDs is divided into multiple light beams by multiple element lenses arranged in one direction perpendicular to the optical axis, and the irradiation areas of the multiple light beams are overlapped on the irradiation surface by a condenser lens unit. This makes it possible to irradiate the irradiation surface with high-intensity light having a uniform intensity distribution. In addition, in the device of Patent Document 1, a spatial light modulator is arranged on the irradiation surface. The light spatially modulated by the spatial light modulator is irradiated onto the substrate, and a pattern is drawn. Patent Documents 2 to 4 disclose a method of changing the intensity of the laser light by a variable attenuator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-192080 A [Patent Document 2] JP 2009-123888 A [Patent Document 3] JP 2005-33007 A [Patent Document 4] JP 2015-118225 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a photosensitive material is applied or laminated to a substrate on which a pattern is drawn, and the sensitivity of the photosensitive material varies depending on optical characteristics such as the light wavelength, so a function for changing the light intensity is required. When an LD is used as a light source as in Patent Document 1, it is possible to change the light intensity by controlling the driving current value of the LD, but the position of the light emitting point may shift due to a change in the heat generation state of the LD, and the light intensity distribution on the irradiation surface may become uneven. Therefore, as in Patent Documents 2 to 4, it is possible to change the light intensity while keeping the driving current value and heat generation state of the LD constant by using a variable attenuator. However, since the variable attenuator is usually placed at a position where the light is parallel, it is necessary to add a lens to form parallel light in the optical system, which may increase the size of the light irradiation device.

[0005] The present invention has been made in consideration of the above problems, and has an object to appropriately irradiate an irradiation surface with light of a desired intensity while avoiding an increase in the size of a light irradiation device. [Means for solving the problem]

[0006] The invention described in claim 1 is a light irradiation device comprising: a light source unit that emits light toward a predetermined position; and an irradiation optical system that is arranged at the predetermined position and guides the light to an irradiation surface along an optical axis, the irradiation optical system being arranged at a position where the light is diverging or converging when viewed along a certain direction perpendicular to the optical axis, the variable attenuator that changes the intensity of the light by changing the angle of a light-transmitting plate that is a flat plate whose normals to both main surfaces are perpendicular to the certain direction, relative to the optical axis, and a focus lens mechanism that moves a lens that is arranged between the variable attenuator and the irradiation surface along the optical axis, thereby positioning a focusing position of the light on the irradiation surface when viewed along the certain direction.

[0007] The invention described in claim 2 is the light irradiation device described in claim 1, further comprising a focus control unit that controls the focus lens mechanism using information indicating the relationship between the angle of the light-transmitting plate with respect to the optical axis and the amount of movement of the lens to position the focusing position of the light on the irradiation surface.

[0008] The invention described in claim 3 is the light irradiation device described in claim 1 or 2, wherein the variable attenuator has another light-transmitting plate having a structure similar to that of the light-transmitting plate, and in the variable attenuator, the light-transmitting plate and the other light-transmitting plate are aligned along the optical axis, and when viewed along the one direction, the light-transmitting plate and the other light-transmitting plate are in a symmetrical position with respect to a line perpendicular to the optical axis assumed between them.

[0009] The invention described in claim 4 is a light irradiation device described in any one of claims 1 to 3, wherein the irradiation optical system has a plurality of element lenses arranged in the one direction, and comprises a splitting lens section that splits the light into a plurality of light beams by the plurality of element lenses, and a focusing section that is arranged between the splitting lens section and the irradiation surface and overlaps the irradiation areas of the plurality of light beams on the irradiation surface, wherein the light is focused inside or near the splitting lens section when viewed along the one direction, and the light-transmitting plate of the variable attenuator is arranged between the splitting lens section and the lens of the focus lens mechanism.

[0010] The invention described in claim 5 is a drawing device comprising: a light irradiation device described in any one of claims 1 to 4; a spatial light modulator arranged on the irradiation surface of the light irradiation device; a projection optical system that guides light spatially modulated by the spatial light modulator onto an object; a moving mechanism that moves an irradiation position on the object of the spatially modulated light; and a control unit that controls the spatial light modulator in synchronization with movement of the irradiation position by the moving mechanism. Effect of the Invention

[0011] According to the present invention, it is possible to appropriately irradiate an irradiation surface with light of a desired intensity while avoiding an increase in the size of the light irradiation device. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 illustrates a configuration of a drawing device. [Diagram 2] FIG. 2 is a diagram showing a configuration of a light irradiation device. [Diagram 3] FIG. 2 is a diagram showing a configuration of a light irradiation device. [Figure 4] FIG. 2 is a diagram showing the light intensity distribution on an irradiation surface. [Diagram 5] FIG. 1 is a diagram showing an optical system using two parallel plates. [Figure 6A] FIG. 1 is a diagram showing the results of ray tracing in an optical system. [Figure 6B] FIG. 1 is a diagram showing the results of ray tracing in an optical system. [Figure 7A] FIG. 1 is a diagram showing the results of ray tracing in an optical system. [Figure 7B] FIG. 1 is a diagram showing the results of ray tracing in an optical system. [Figure 8] FIG. 13 is a diagram for explaining an optical path when a parallel plate is inserted. [Figure 9] 5 is a diagram showing the relationship between the attenuation rate of a variable attenuator, the rotation angle of the variable attenuator, and the movement amount of a focus lens mechanism. [Figure 10A] FIG. 1 is a diagram showing the results of ray tracing in an optical system. [Figure 10B] FIG. 1 is a diagram showing the results of ray tracing in an optical system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] FIG. 1 is a diagram showing a configuration of a drawing apparatus 1 according to an embodiment of the present invention. The drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating a light beam onto a surface of a substrate 9, such as a semiconductor substrate, a resin substrate, or a glass substrate, on which a photosensitive material is applied, and is used in the manufacture of semiconductor devices, printed wiring boards, flat panel displays (FPDs), and the like. The drawing apparatus 1 includes a stage 21, a moving mechanism 22, a light irradiation device 31, a spatial light modulator 32, a projection optical system 33, and a control unit 11. The stage 21 holds the substrate 9. The moving mechanism 22 has a motor or the like, and moves the stage 21 along the main surface of the substrate 9. The moving mechanism 22 may rotate the substrate 9 about an axis perpendicular to the main surface.

[0014] The light irradiation device 31 irradiates the spatial light modulator 32 with a line-shaped light via a mirror 39. The light irradiation device 31 will be described in detail later. The spatial light modulator 32 is, for example, a diffraction grating type and a reflective type, and is a diffraction grating whose grating depth can be changed. The spatial light modulator 32 is manufactured using a semiconductor device manufacturing technology. The diffraction grating type light modulator used in this embodiment is, for example, a GLV (Grating Light Valve) (registered trademark). The spatial light modulator 32 has a plurality of grating elements arranged in a row, and each grating element transitions between a state in which a first-order diffracted light is emitted and a state in which a zeroth-order diffracted light (zeroth-order light) is emitted. In this way, spatially modulated light is emitted from the spatial light modulator 32.

[0015] The projection optical system 33 includes a light shielding plate 331, a lens 332, a lens 333, an aperture plate 334, and a focusing lens 335. The light shielding plate 331 blocks ghost light and a part of high-order diffracted light, and passes light from the spatial light modulator 32. The lenses 332 and 333 form a zoom section. The aperture plate 334 blocks (±1)-order diffracted light (and high-order diffracted light), and passes 0-order diffracted light. The light that has passed through the aperture plate 334 is guided onto the main surface of the substrate 9 by the focusing lens 335. In this way, the light spatially modulated by the spatial light modulator 32 is guided onto the substrate 9 by the projection optical system 33.

[0016] The control unit 11 is connected to the light irradiation device 31, the spatial light modulator 32, and the moving mechanism 22, and controls these components. The control unit 11 is realized, for example, by a computer equipped with a CPU, a memory, etc. All or part of the functions of the control unit 11 may be realized by an electric circuit. In the drawing device 1, the moving mechanism 22 moves the stage 21, thereby moving the irradiation position on the substrate 9 of the light from the spatial light modulator 32. Furthermore, the control unit 11 controls the spatial light modulator 32 in synchronization with the movement of the irradiation position by the moving mechanism 22. As a result, a desired pattern is drawn on the photosensitive material on the substrate 9.

[0017] Fig. 2 and Fig. 3 are diagrams showing the configuration of the light irradiation device 31. In Fig. 2 and Fig. 3, a direction parallel to an optical axis J1 of an irradiation optical system 5 described later is shown as the Z direction, and directions perpendicular to the Z direction and perpendicular to each other are shown as the X direction and the Y direction (same below). Fig. 2 shows the configuration of the light irradiation device 31 seen along the Y direction, and Fig. 3 shows the configuration of the light irradiation device 31 seen along the X direction.

[0018] The light irradiation device 31 shown in FIG. 2 and FIG. 3 includes a light source unit 40 and an irradiation optical system 5. The light source unit 40 has a plurality of light source sections 4, and each light source section 4 has one light source 41 and one collimator lens 42. The light source 41 in this embodiment is a semiconductor laser (LD). The light sources 41 of the plurality of light source sections 4 are arranged in approximately the X direction on a plane parallel to the ZX plane (hereinafter referred to as the "light source arrangement plane"). The laser light emitted from each light source 41 is collimated by the collimator lens 42 and enters the irradiation optical system 5. The light source unit 40 is provided with a mechanism (not shown) for adjusting the emission direction of the laser light emitted from the light source section 4. By adjusting the mechanism, it is possible to approximately match the positions on the irradiation optical system 5 where the laser light from the plurality of light source sections 4 is irradiated. In this way, in the light source unit 40, laser light is emitted from multiple light source sections 4 arranged on the light source array surface toward the same position on the irradiation optical system 5 (the split lens section 62 described later) from different directions along the light source array surface.

[0019] The irradiation optical system 5 is disposed at a position where the laser light is irradiated by the light source unit 40. The irradiation optical system 5 guides the laser light along the optical axis J1 to the surface of the spatial light modulator 32, which is the irradiation surface (indicated by a solid line with reference numeral 320 in Figs. 2 and 3), i.e., the surfaces of the multiple grating elements. As described above, the light from the light irradiation device 31 is irradiated to the spatial light modulator 32 via the mirror 39, and therefore the light irradiation device 31 actually includes the mirror 39 as a component, but in Figs. 2 and 3, the mirror 39 is omitted for convenience of illustration (the same applies below).

[0020] The irradiation optical system 5 includes a cylinder lens 611, a divided lens section 62, an optical path length difference generating section 63, a cylinder lens 641, a condensing section 65, and a focus lens mechanism 67. In the irradiation optical system 5, these components are arranged along the optical axis J1 in the following order from the light source unit 40 toward the irradiation surface 320: the cylinder lens 611, the divided lens section 62, the optical path length difference generating section 63, the cylinder lens 641, the condensing section 65, and the focus lens mechanism 67.

[0021] The cylinder lens 611 has a positive power only in the Y direction. The divided lens section 62 includes a plurality of lenses 620 (hereinafter referred to as "element lenses 620") that are densely arranged at a constant pitch in a direction perpendicular to the optical axis J1 of the irradiation optical system 5 and along the light source array surface (here, the X direction). The divided lens section 62 is a so-called fly-eye lens. Each element lens 620 is substantially block-shaped, and has a first lens surface that is a surface located on the (-Z) side (the cylinder lens 611 side) and a second lens surface that is a surface located on the (+Z) side (the optical path length difference generating section 63 side). The first lens surface and the second lens surface are symmetrical with respect to a plane perpendicular to the optical axis J1. For example, the first lens surface is disposed at the focal point of the second lens surface, and the second lens surface is disposed at the focal point of the first lens surface. That is, the focal lengths of the first lens surface and the second lens surface are the same. The lens elements 620 stacked in the X direction may be formed as a continuous member, or the lens elements 620 may be individually formed and bonded to each other.

[0022] The optical path length difference generating unit 63 includes a plurality of light transmitting portions 630 densely arranged at a constant pitch in a direction (X direction) perpendicular to the optical axis J1 and along the light source array surface. In the example of FIG. 2, the number of light transmitting portions 630 in the optical path length difference generating unit 63 is one less than the number of element lenses 620 in the divided lens unit 62. The arrangement pitch of the light transmitting portions 630 is equal to the arrangement pitch of the element lenses 620. Each light transmitting portion 630 is in the shape of a block having a surface perpendicular to the X direction, the Y direction, and the Z direction. The light transmitting portions 630 arranged in a line in the X direction have the same length in the X direction and the Y direction, and the lengths in the Z direction, i.e., in the optical axis J1 direction, are different from each other. In this way, the light transmitting portions 630 have different optical path lengths from each other.

[0023] In the example of FIG. 2, the length of the plurality of light transmitting portions 630 in the optical axis J1 direction is smaller as the light transmitting portions 630 are located closer to the (+X) side. The lengths of the plurality of light transmitting portions 630 in the optical axis J1 direction do not necessarily need to be successively longer (or shorter) along the X direction, and may have any concave-convex shape. In this embodiment, the plurality of light transmitting portions 630 in the optical path length difference generating portion 63 are formed as a continuous member using the same material. In the optical path length difference generating portion 63, the plurality of light transmitting portions 630 formed individually may be joined together.

[0024] The cylinder lens 641 has a negative power only in the Y direction. The light collecting unit 65 has a first imaging lens 651 and a second imaging lens 652. The first imaging lens 651 and the second imaging lens 652 are arranged in order along the optical axis J1, and both have positive power. A first light-transmitting plate 661 and a second light-transmitting plate 662 of the variable attenuator 66 are provided between the first imaging lens 651 and the second imaging lens 652. The variable attenuator 66 will be described in detail later. The focus lens mechanism 67 includes a cylinder lens 671 and a lens moving mechanism 672. The cylinder lens 671 has a positive power only in the Y direction. The lens moving mechanism 672 has a motor or the like, and moves the cylinder lens 671 along the optical axis J1.

[0025] When viewed along the Y direction as shown in FIG. 2, collimated laser light from the multiple light source units 4 passes through the cylindrical lens 611 and enters the divided lens unit 62 in the form of parallel light. In the multiple element lenses 620, the light from the light source unit 40 is divided in the X direction. At this time, parallel light from each light source unit 4 enters a first lens surface of each element lens 620 and is collected on or near a second lens surface. The light (multiple light beams) divided by the multiple element lenses 620 are emitted from the second lens surface so that the main ray is parallel to the optical axis J1. The light beams emitted from each element lens 620 enter the optical path length difference generating unit 63 while diverging.

[0026] The divided lens section 62 and the optical path length difference generating section 63 are disposed close to each other in the Z direction, and the lens elements 620, excluding the lens element 620 on the (+X) side, and the light-transmitting sections 630 are disposed at the same positions in the X direction. Therefore, the light beams passing through these lens elements 620 are transmitted through the light-transmitting sections 630. The light beams passing through the lens element 620 on the (+X) side do not pass through any of the light-transmitting sections 630. The optical path length difference generating section 63 may be provided with the same number of light-transmitting sections 630 as the lens element 620 in the divided lens section 62. In this case, the light beams passing through the lens element 620 (all of them) enter the light-transmitting sections 630.

[0027] The multiple light beams that have passed through the optical path length difference generating unit 63 (including the light beams that have not passed through any of the light transmitting units 630) pass through the cylinder lens 641, the first imaging lens 651, the variable attenuator 66, and the second imaging lens 652 in this order. When viewed along the Y direction, the multiple light beams emitted from the second imaging lens 652 become substantially parallel light due to the action of the light collecting unit 65 (the first imaging lens 651 and the second imaging lens 652), pass through the cylinder lens 671, and are superimposed on the irradiation surface 320. That is, the irradiation areas 50 of the multiple light beams emitted from the multiple element lenses 620 are entirely superimposed on the irradiation surface 320. As described above, the spatial light modulator 32 is disposed on the irradiation surface 320. In FIG. 2 and FIG. 3, the irradiation area 50 is indicated by a thick solid line.

[0028] The irradiation area 50 has a certain width in the X direction. As described above, since the multiple light beams emitted from the multiple element lenses 620 pass through different light-transmitting sections 630, a difference in optical path length occurs between the divided lens section 62 and the irradiation surface 320. Therefore, the occurrence of interference fringes on the irradiation surface 320 due to the interference of the light split by the multiple element lenses 620 is suppressed (or prevented). As a result, as shown in the upper part of FIG. 4, the intensity distribution of light in the X direction on the irradiation surface 320 becomes uniform. In each combination of two light-transmitting sections 630 among the multiple light-transmitting sections 630, it is preferable that the difference in optical path length of the light beams passing through the two light-transmitting sections 630 is equal to or greater than the coherence length of the laser light emitted from the light source section 4.

[0029] When viewed along the X direction as shown in FIG. 3, parallel light from the light source unit 40 is converged by the cylinder lens 611 and enters the divided lens section 62. The light is condensed at or near the first lens surface of the element lens 620 (which may be inside or outside the element lens 620) and is emitted as parallel light from the second lens surface. The light that has passed through the optical path length difference generating section 63 is made into divergent light by the cylinder lens 641 and passes through the first imaging lens 651, the variable attenuator 66, and the second imaging lens 652 in this order. The light that is emitted from the second imaging lens 652 is made into parallel light by the action of the condensing section 65 (the first imaging lens 651 and the second imaging lens 652) and enters the cylinder lens 671 of the focus lens mechanism 67.

[0030] The light emitted from the cylindrical lens 671 is focused on the irradiation surface 320. Therefore, on the irradiation surface 320, the irradiation area 50 of the light from each element lens 620 is linear extending in the X direction. This results in line illumination light, which is a collection of light that has passed through the multiple element lenses 620 and whose cross section on the irradiation surface 320 (i.e., the light flux cross section perpendicular to the optical axis J1) is linear extending in the X direction. The lower part of FIG. 4 shows the intensity distribution of the line illumination light in the Y direction. The width of the line illumination light in the Y direction is, for example, several tens of μm, and the width in the X direction is, for example, several tens of mm.

[0031] Next, the variable attenuator 66 will be described. As shown in Fig. 3, the variable attenuator 66 includes a first light-transmitting plate 661, a second light-transmitting plate 662, and a light-transmitting plate rotating mechanism 663. The first light-transmitting plate 661 and the second light-transmitting plate 662 are arranged along the optical axis J1 between the first imaging lens 651 and the second imaging lens 652. Each of the first light-transmitting plate 661 and the second light-transmitting plate 662 is a flat plate whose normal lines of both main surfaces are perpendicular to the X direction. For example, the main surfaces of the light-transmitting plates 661 and 662 are coated with a dielectric multilayer film or the like whose transmittance changes depending on the angle of incidence.

[0032] The light-transmitting plate rotating mechanism 663 rotates each of the first light-transmitting plate 661 and the second light-transmitting plate 662 about an axis parallel to the X direction. In the following description, the angle between the normal of each light-transmitting plate 661, 662 and the optical axis J1 when viewed along the X direction is referred to as the "rotation angle". In the initial positions of the light-transmitting plates 661, 662, the rotation angle is 0°. In the light-transmitting plate rotating mechanism 663, the first light-transmitting plate 661 and the second light-transmitting plate 662 are connected to one motor via, for example, a no-backlash gear or the like, and rotate by the same angle in different rotation directions. Therefore, the first light-transmitting plate 661 and the second light-transmitting plate 662 are always in a symmetrical position with respect to a line K1 (shown by a two-dot chain line in FIG. 3) perpendicular to the optical axis J1, which is assumed to be at the center between them in the optical axis J1 direction. By changing the angles (ie, rotation angles) of the first light-transmitting plate 661 and the second light-transmitting plate 662 with respect to the optical axis J1, it is possible to change the intensity of the light passing through the variable attenuator 66.

[0033] As described above, the variable attenuator 66 is disposed at a position where the light becomes divergent when viewed along the X direction. In this case, when the angles of the first light-transmitting plate 661 and the second light-transmitting plate 662 with respect to the optical axis J1 are changed, the light collecting position of the light viewed along the X direction in the vicinity of the irradiation surface 320 moves (shifts) in the direction of the optical axis J1. Hereinafter, the phenomenon in which the light collecting position shifts in the direction of the optical axis J1 due to the rotation of the light-transmitting plates 661 and 662 will be described.

[0034] FIG. 5 is a diagram showing an optical system 81 using two parallel plates 811. In the optical system 81 of FIG. 5, light from an object plane 810 is guided to an image plane 819 by a lens 812, and the two parallel plates 811 are disposed at a position between the lens 812 and the image plane 819, that is, a position where the light becomes a convergent light. The two parallel plates 811 correspond to the first light-transmitting plate 661 and the second light-transmitting plate 662 of the variable attenuator 66. The focal length of the lens 812 is f=60 mm. In FIG. 5, the left-right direction is the Z direction, the up-down direction is the Y direction, and the direction perpendicular to the paper surface is the X direction.

[0035] 6A and 6B are diagrams showing the results of ray tracing in optical system 81 when the rotation angle of each parallel plate 811 is 0°. Fig. 6A shows light rays in the vicinity of lens 812 and two parallel plates 811, and Fig. 6B shows light rays in the vicinity of image plane 819. In Fig. 6A and 6B, the position of image plane 819 in the Z direction is 77.268 mm based on the optical axis exit of parallel plate 811 on the (+Z) side.

[0036] 7A and 7B are diagrams showing the results of ray tracing in the optical system 81 when the two parallel plates 811 are rotated in different rotation directions and the rotation angle is 30°. FIG. 7A and FIG. 7B correspond to FIG. 6A and FIG. 6B, respectively. FIG. 7B also shows a reference plane 818 at the same position in the Z direction as the image plane 819 in FIG. 6B. Comparing FIG. 6B and FIG. 7B, the thickness of the light beam group at the reference plane 818 in FIG. 7B is larger than the thickness of the light beam group at the image plane 819 in FIG. 6B. That is, in FIG. 7B, the light condensing point is shifted toward the (+Z) side from the reference plane 818 corresponding to the image plane 819 in FIG. 6B. In the examples of FIG. 6B and FIG. 7B, the position of the best light condensing point (or the best image plane) has moved from 77.268 mm to 77.837 mm.

[0037] 7A and 7B, in order to return the focal point to its original position (the position of the reference surface 818) without changing the object-to-image distance, it is necessary to move the lens 812 to the object side ((-Z) side). In this case, the NA on the image side changes, and the magnification and the imaging position (Y direction) of the off-axis object also change.

[0038] As shown in FIG. 8, when a parallel plate 821 with a refractive index n and a thickness d is inserted, in paraxial calculation, the distance PP' by which the image plane moves backward is obtained by Equation 1.

[0039] (Number 1) PP'=(1-1 / n)·d If the horizontal magnification of the imaging system in Figure 8 is M, then the vertical magnification is M 2 Therefore, the lens (not shown) is rotated in the optical axis direction (Z direction) to (PP' / M 2), the image plane can be moved to the focal position where the parallel plate 821 would be absent. In the case of Fig. 7A and Fig. 7B, the thickness of one parallel plate 811 is D, and the effective thickness d (length in the Z direction on a cross section perpendicular to the Y direction) in Equation 1 changes from 2D to 2D / cos(θ) by rotating the parallel plate 811 by a rotation angle θ, and the image formation position changes accordingly. Note that the insertion of the parallel plate 811 into the optical path affects the image formation by influencing spherical aberration, coma aberration, curvature of field, astigmatism, distortion aberration, and the like, so it is preferable to design the lens so that the practical effect is small with respect to the amount of movement of the lens.

[0040] In the optical system 81, a structure in which the object side and the image forming side are interchanged is used for the irradiation optical system 5 in FIG. 2 and FIG. 3. When viewed along the Y direction as shown in FIG. 2, the exit of the divided lens section 62 corresponds to the image point of the optical system 81. When viewed along the X direction as shown in FIG. 3, the entrance of the divided lens section 62 corresponds to the image point of the optical system 81. When the effective thickness d in Equation 1 changes due to the rotation of the light-transmitting plates 661, 662 in the variable attenuator 66, in FIG. 2 viewed along the Y direction, the state of the approximately parallel light on the (+Z) side from the light-condensing section 65 (the first imaging lens 651 and the second imaging lens 652) is broken, and the light reaches the irradiation surface 320, that is, the surface of the spatial light modulator 32. However, even in this case, the effect on the uniformity of the intensity of the line illumination light on the irradiation surface 320 is small. In reality, the width of the linear illumination light in the X direction changes, but by designing it to illuminate an area wider than the modulatable area on the surface of the spatial light modulator 32, no practical problem occurs.

[0041] On the other hand, in FIG. 3 viewed along the X direction, the light-collecting position is shifted in the direction of the optical axis J1 due to a change in the substantial thickness d of the light-transmitting plates 661 and 662. In order to ensure the accuracy of pattern drawing in the drawing device 1, it is necessary to arrange the light-collecting position on the surface of the spatial light modulator 32. In order to eliminate the shift in the light-collecting position, the irradiation optical system 5 moves the cylinder lens 671 of the focus lens mechanism 67 back and forth along the optical axis J1 to arrange the light-collecting position on the irradiation surface 320, that is, to focus on the surface of the spatial light modulator 32. In the example of FIG. 3, the light-transmitting plates 661 and 662 are arranged at positions where the light is diverging, but the same applies when they are arranged at positions where the light is converging.

[0042] 3, the irradiation optical system 5 further includes an attenuator control unit 51 and a focus control unit 52. The attenuator control unit 51 and the focus control unit 52 may be part of the control unit 11 in FIG. 1. The attenuator control unit 51 controls a variable attenuator 66. The focus control unit 52 controls a focus lens mechanism 67.

[0043] FIG. 9 is a diagram showing the relationship between the attenuation rate of the variable attenuator 66, the rotation angle of the variable attenuator 66, and the movement amount of the focus lens mechanism 67. The attenuation rate of the variable attenuator 66 indicates the attenuation rate of light by the variable attenuator 66. The rotation angle of the variable attenuator 66 indicates the rotation angle of the light-transmitting plates 661 and 662. The movement amount of the focus lens mechanism 67 indicates the movement amount of the cylinder lens 671 in the Z direction from a predetermined reference position in order to arrange the light collection position on the irradiation surface 320 when viewed along the X direction. Line L1 in FIG. 9 indicates the relationship between the attenuation rate of the variable attenuator 66 and the rotation angle of the variable attenuator 66, and line L2 indicates the relationship between the attenuation rate of the variable attenuator 66 and the movement amount of the focus lens mechanism 67. These relationships can be obtained by experiments, calculations, etc. The values ​​on the vertical axis on the left and right sides of FIG. 9 indicate values ​​related to the number of motor pulses. However, 0 on the left vertical axis indicates that the rotation angle is 0°, and 0 on the right vertical axis indicates that the movement amount is 0.

[0044] In the light irradiation device 31 in Fig. 1, rotation angle-movement amount information 521 indicating the relationship between the rotation angle of the variable attenuator 66 and the movement amount of the focus lens mechanism 67 is stored in advance in the focus control unit 52. The rotation angle-movement amount information 521 can be derived, for example, from Fig. 9. The rotation angle-movement amount information 521 may be an approximation formula or a table.

[0045] When a pattern is drawn in the drawing device 1, the driving current value of each light source (LD) 41 is kept constant, and a constant heat generation state is maintained. In the control unit 11 of FIG. 1, the exposure dose according to the sensitivity of the photosensitive material on the substrate 9 is set. In addition, the moving speed of the substrate 9 by the moving mechanism 22 is also set. From the set value of the exposure dose and the set value of the moving speed, the attenuation factor required in the variable attenuator 66 is obtained, and the set value of the rotation angle of the variable attenuator 66 is determined. Note that the relationship between the exposure dose for the substrate 9, the moving speed of the substrate 9, and the rotation angle of the variable attenuator 66 may be obtained in advance, and the set value of the rotation angle of the variable attenuator 66 may be determined from the set value of the exposure dose and the set value of the moving speed.

[0046] When the set value of the rotation angle of the variable attenuator 66 is determined, the set value of the movement amount of the focus lens mechanism 67 corresponding to the set value of the rotation angle is specified from the rotation angle-movement amount information 521. After that, the attenuator control unit 51 controls the variable attenuator 66, and the rotation angle of the light-transmitting plates 661, 662 is adjusted to the set value. In addition, the focus control unit 52 controls the focus lens mechanism 67, and the cylinder lens 671 is moved in the Z direction from the reference position by the set value of the movement amount. As a result, the light collecting position viewed along the X direction is positioned on the irradiation surface 320. When actually drawing a pattern, the spatial light modulator 32 is controlled while the substrate 9 is continuously moved at the set value of the movement speed, and the pattern is drawn on the substrate 9.

[0047] When fine patterning or alignment is required, it is preferable to detect an optical image of the light beam by an imaging unit or the like provided on the stage 21 after the rotation of the light-transmitting plates 661, 662 and the movement of the cylindrical lens 671. In this case, by adjusting the control timing of the multiple grating elements in the spatial light modulator 32 based on the optical image, it is possible to correct the width and irradiation position of the irradiation area on the stage 21, the influence of the inclination of the line illumination light on the irradiation surface 320, and the like.

[0048] Here, a light irradiation device of a comparative example is assumed, which uses a variable attenuator to irradiate light of a desired intensity onto an irradiation surface. The variable attenuator is usually placed at a position where the light is parallel, so a lens for forming parallel light is added in the light irradiation device of the comparative example. In this case, the total length of the irradiation optical system becomes long, and the size becomes large. In addition, in the light irradiation device of the comparative example, when the variable attenuator is placed at a position where the light is divergent, as described with reference to Figs. 6B and 7B, the rotation angle of the light-transmitting plate is changed, and the light-focusing position of the light that has passed through the light-transmitting plate changes. As a result, the light cannot be appropriately focused on the irradiation surface.

[0049] 2 and 3, the irradiation optical system 5 includes a variable attenuator 66 and a focus lens mechanism 67. The variable attenuator 66 is disposed at a position where the light is divergent when viewed along a direction perpendicular to the optical axis J1, and changes the intensity of the light by changing the angle of the light-transmitting plates 661 and 662, which are flat plates whose normals to both main surfaces are perpendicular to the direction, relative to the optical axis J1. The focus lens mechanism 67 moves a cylinder lens 671 disposed between the variable attenuator 66 and the irradiation surface 320 along the optical axis J1, thereby positioning the condensed position of the light on the irradiation surface 320 when viewed along the direction.

[0050] In this way, by arranging the variable attenuator 66 at a position where the light is not parallel, the degree of freedom of optical design is increased, and a design in which the total length of the irradiation optical system 5 is long can be avoided, that is, the size of the light irradiation device 31 can be avoided. This allows the light irradiation device 31 to be lightweight and compact. In addition, the focus lens mechanism 67 moves the cylindrical lens 671 in accordance with the rotation angle of the light-transmitting plates 661 and 662, so that the light collection position can be located on the irradiation surface 320. As a result, light of a desired intensity can be appropriately irradiated onto the irradiation surface 320. In the drawing device 1 having the light irradiation device 31, a pattern can be drawn with high precision, and good exposure quality can be achieved.

[0051] Preferably, the light irradiation device 31 further includes a focus control unit 52. The focus control unit 52 controls the focus lens mechanism 67 using information (rotation angle-movement amount information 521 in the above processing example) indicating the relationship between the angle of the light-transmitting plates 661, 662 with respect to the optical axis J1 and the movement amount of the cylindrical lens 671 for arranging the light focusing position on the irradiation surface 320. This makes it possible to easily arrange the light focusing position of the light changed to a desired intensity on the irradiation surface 320.

[0052] Preferably, the irradiation optical system 5 includes a split lens unit 62 and a condenser unit 65. The split lens unit 62 has a plurality of element lenses 620 arranged in the one direction, and splits light into a plurality of light beams by the plurality of element lenses 620. The condenser unit 65 is disposed between the split lens unit 62 and the irradiation surface 320, and overlaps the irradiation areas 50 of the plurality of light beams on the irradiation surface 320. In addition, when viewed along the one direction, the light is condensed inside or near the split lens unit 62, and the light-transmitting plates 661, 662 of the variable attenuator 66 are disposed between the split lens unit 62 and a cylindrical lens 671 of the focus lens mechanism 67.

[0053] In this way, by arranging the light-transmitting plates 661, 662 of the variable attenuator 66 at the position where the light passes through the divided lens section 62 and becomes divergent light, it is possible to significantly reduce the size of the light irradiation device 31 compared to a design in which a position where the light becomes parallel light is provided and a variable attenuator is arranged at that position, as in the light irradiation device of the comparative example. Note that the position inside or near the divided lens section 62 where the light is condensed when viewed along the one direction may be, for example, a position where the light passing through the divided lens section 62 does not pass through (is not eclipsed by) the edge of the divided lens section 62.

[0054] As described above, even when the light-transmitting plates 661, 662 are arranged at positions where the light is convergent when viewed along the X direction, the light-collecting position is shifted in the direction of the optical axis J1 due to the rotation of the light-transmitting plates 661, 662. Therefore, when the light-transmitting plates 661, 662 are arranged at positions where the light is divergent or convergent when viewed along the X direction, a focus lens mechanism 67 is required to position the light-collecting position on the irradiation surface 320. From the viewpoint of reducing the shift in the light-collecting position due to the rotation of the light-transmitting plates 661, 662, it is preferable that the thickness of each of the light-transmitting plates 661, 662 is as thin as possible, for example, less than 5 mm.

[0055] Next, a case where the light collecting position in the vicinity of the irradiation surface 320 is shifted in the Y direction will be described. As described above, in the optical system 81 of FIG. 5, when the parallel plate 811 is rotated, a magnification change occurs, and when the object is arranged to be shifted from the optical axis, the image forming position in the Y direction is also shifted. In FIG. 10A, the result of ray tracing for the first object arranged on the optical axis J2 in the optical system 81 is given the symbol R1, and the result of ray tracing for the second object arranged to be slightly shifted from the optical axis J2 to the (-Y) side is given the symbol R2. Also, FIG. 10B shows a case where the lens 812 is slightly shifted to the (-Y) side in accordance with the shift of the second object from the optical axis J2. In FIG. 10B, the result of ray tracing for the first object arranged on the optical axis J2 is given the symbol R3, and the result of ray tracing for the second object arranged to be slightly shifted from the optical axis J2 to the (-Y) side is given the symbol R4. In addition, in FIGS. 10A and 10B, the rotation angle of the parallel plate 811 is fixed at 0°.

[0056] As is clear from FIG. 10A and FIG. 10B, the movement of the lens 812 causes the focusing position of the light beam with respect to the second object to move downward. In the irradiation optical system 5 of FIG. 3, even if the imaging position is shifted in the Y direction due to the rotation of the light-transmitting plates 661, 662, it is possible to correct the imaging position by moving the cylinder lens 671 in the focus lens mechanism 67 in the Y direction. Therefore, in a preferred focus lens mechanism 67, the cylinder lens 671 can also be moved in the Y direction by the lens movement mechanism 672. Also, if the focusing position at the entrance of the divided lens section 62 is shifted in the Y direction, the focusing position will also shift in the Y direction with respect to the optical axis J1 on the surface (irradiation surface 320) of the spatial light modulator 32. In this case, too, it is possible to correct the shift by moving the cylinder lens 671 in the Y direction. Note that the optical performance is degraded by the movement of the cylinder lens 671 in the Y direction, so this method is used as a correction function within a range that does not cause practical problems.

[0057] However, when the current supplied to the LD, which is the light source 41, changes, or when the temperature of the LD changes due to deterioration or the like, the position of the light emission point of the LD moves, and the light collection position on the surface of the spatial light modulator 32 may change. The movement of the light emission point of the LD may occur in any of the X direction, the Y direction, and the Z direction. Therefore, when the lens of the focus lens mechanism 67 has power in the X direction in addition to the Y direction, the above method of moving the lens can also be applied to the X direction. In this way, as a correction method when the movement of the light emission point of the LD occurs, it is possible to use a method of moving the lens of the focus lens mechanism 67 in the X direction, the Y direction, and the Z direction.

[0058] The light irradiation device 31 and the imaging device 1 can be modified in various ways.

[0059] In the above embodiment, the variable attenuator 66 is provided with two light-transmitting plates 661, 662, but one or three or more light-transmitting plates may be provided depending on the design of the light irradiation device 31. On the other hand, in the variable attenuator, the two light-transmitting plates 661, 662 are rotated by the same angle in different rotation directions, so that the deviation of the optical path passing through the two light-transmitting plates 661, 662 is reduced. Therefore, it is preferable that the variable attenuator 66 has two light-transmitting plates 661, 662 having the same structure. In this case, the two light-transmitting plates 661, 662 are aligned along the optical axis J1, and when viewed along one direction perpendicular to the optical axis J1, the two light-transmitting plates 661, 662 maintain a symmetrical attitude with respect to a line perpendicular to the optical axis J1 assumed between them. This can reduce the deviation of the optical path in the variable attenuator 66, and can reduce the amount of movement of the cylinder lens 671 of the focus lens mechanism 67. The same applies to the case where the above-mentioned two light-transmitting plates 661, 662 are used as a light-transmitting plate pair and two or more light-transmitting plate pairs are provided.

[0060] As described above, the lens of the focus lens mechanism 67 may have power in both the X and Y directions. That is, the lens of the focus lens mechanism 67 does not necessarily have to be a cylindrical lens. The movement amount of the cylindrical lens 671 may be specified without using the rotation angle-movement amount information 521. The position (movement amount) of the cylindrical lens 671 in the optical axis J1 direction may be determined based on, for example, an optical image obtained by an imaging unit on the stage 21, as long as it is possible to arrange the light focusing position on the irradiation surface 320.

[0061] In the divided lens section 62, the element lenses 620 may be cylindrical lenses having power only in the X direction. The condenser section 65 may be composed of one or three or more lenses, and each lens may be a cylindrical lens having power only in the X direction. In the irradiation optical system 5, the optical path length difference generating section 63 may be omitted. The variable attenuator 66 and the focus lens mechanism 67 may be used in various types of irradiation optical systems that do not have the divided lens section 62 and the condenser section 65.

[0062] The number of light source units 4 may be one. On the other hand, in a configuration in which light from a plurality of light source units 4 is incident on the irradiation optical system 5, the position where the variable attenuator 66 can be arranged is significantly limited, so that the above-mentioned method using the variable attenuator 66 and the focus lens mechanism 67 is suitable for the light irradiation device 31 having a plurality of light source units 4. In the light source unit 4, a light source other than a semiconductor laser (LD), such as an LED, may be used.

[0063] In the imaging device 1, the spatial light modulator 32 arranged on the irradiation surface 320 of the light irradiation device 31 may be a type other than a diffraction grating type light modulator, and for example, a spatial light modulator using a collection of minute mirrors may be used.

[0064] The moving mechanism for moving the light irradiation position on the substrate 9 may be other than the moving mechanism 22 for moving the stage 21, and may be, for example, a moving mechanism for moving a head including the light irradiation device 31, the spatial light modulator 32 and the projection optical system 33 relative to the substrate 9.

[0065] The object on which drawing is performed by the drawing apparatus 1 may be a substrate other than a semiconductor substrate, a resin substrate, or a glass substrate, or may be something other than a substrate. The light irradiation device 31 may be used for something other than the drawing apparatus 1.

[0066] 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]

[0067] 1 Drawing device 4 Light source section 5 Irradiation optical system 9 Substrate 11 Control section 22 Moving mechanism 31 Light irradiation device 32 Spatial Light Modulator 33 Projection optical system 50 irradiation area 52 Focus control section 62 Split lens section 65 Light collecting section 66 Variable Attenuator 67 Focus lens mechanism 320 Irradiation surface 521 Rotation angle - movement amount information 620 element lens 661,662 Translucent plate 671 Cylinder Lens J1 (illumination optical system) optical axis

Claims

1. A light irradiation device, A light source unit that emits light toward a predetermined position; an irradiation optical system that is disposed at the predetermined position and guides the light along an optical axis to an irradiation surface; Equipped with The irradiation optical system includes: a variable attenuator that is arranged at a position where the light is divergent or convergent when viewed along a direction perpendicular to the optical axis, and changes an angle of a light-transmitting plate, which is a flat plate with normals to both main surfaces perpendicular to the direction, with respect to the optical axis, to change an intensity of the light; a focus lens mechanism that moves a lens disposed between the variable attenuator and the irradiation surface along the optical axis to position a focusing position of the light on the irradiation surface when viewed along the one direction; A light irradiation device comprising:

2. The light irradiation device according to claim 1 , A light irradiation device further comprising a focus control unit that controls the focus lens mechanism using information indicating a relationship between an angle of the light-transmitting plate with respect to the optical axis and an amount of movement of the lens to position the focusing position of the light on the irradiation surface.

3. The light irradiation device according to claim 1 or 2, the variable attenuator has another light-transmitting plate having a structure similar to that of the light-transmitting plate, A light irradiation device characterized in that, in the variable attenuator, the light-transmitting plate and the other light-transmitting plate are aligned along the optical axis, and when viewed along the one direction, the light-transmitting plate and the other light-transmitting plate are oriented symmetrically with respect to a line assumed between them that is perpendicular to the optical axis.

4. 4. The light irradiation device according to claim 1, The irradiation optical system includes: a lens division unit having a plurality of lens elements arranged in the one direction and dividing the light into a plurality of light beams by the lens elements; a focusing unit disposed between the split lens unit and the irradiation surface, the focusing unit configuring the irradiation areas of the plurality of light beams to overlap on the irradiation surface; Equipped with A light irradiation device characterized in that, when viewed along the one direction, the light is focused inside or near the split lens portion, and the light-transmitting plate of the variable attenuator is disposed between the split lens portion and the lens of the focus lens mechanism.

5. 1. A drawing device, comprising: A light irradiation device according to any one of claims 1 to 4, a spatial light modulator disposed on the irradiation surface of the light irradiation device; a projection optical system that guides the light spatially modulated by the spatial light modulator onto an object; a moving mechanism for moving an irradiation position on the object of the spatially modulated light; a control unit that controls the spatial light modulator in synchronization with a movement of the irradiation position by the movement mechanism; A drawing device comprising:

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