JP2023046888A - Light irradiation apparatus and drawing apparatus - Google Patents

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

The present invention relates to a light irradiation device and a drawing device.

2. Description of the Related Art Conventionally, a semiconductor laser (LD) has been used as a light source for a drawing apparatus. For example, in the light irradiation device of Patent Document 1, a light source unit that emits laser light from a plurality of LDs toward a predetermined position, and a laser light emitted from the light source unit that is disposed at the predetermined position is irradiated along the optical axis. Illumination optics are provided for directing to. In the irradiation optical system, light incident from a plurality of LDs is divided into a plurality of light beams by a plurality of element lenses arranged in one direction perpendicular to the optical axis, and the plurality of light beams are divided by the condenser lens section. The illuminated areas are superimposed on the illuminated surface. This makes it possible to irradiate the irradiation surface with high-intensity light having a uniform intensity distribution. Further, in the apparatus of Patent Document 1, a spatial light modulator is arranged on the irradiation surface. The substrate is irradiated with light spatially modulated by the spatial light modulator to draw a pattern. Incidentally, Patent Documents 2 to 4 disclose methods of changing the intensity of laser light using a variable attenuator.

JP 2015-192080 A JP 2009-123888 A Japanese Patent Application Laid-Open No. 2005-33007 JP 2015-118225 A

A substrate on which a pattern is drawn is coated or laminated with a photosensitive material. Since the sensitivity of the photosensitive material varies depending on the optical characteristics such as the wavelength of light, a function to change the intensity of light is required. Become. 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 drive current value of the LD. are shifted, and the light intensity distribution on the irradiation surface may become non-uniform. Therefore, as in Patent Documents 2 to 4, it is conceivable to use a variable attenuator to change the light intensity while keeping the driving current value and the heat generation state of the LD constant. However, since the variable attenuator is usually arranged at a position where the light is parallel light, it is necessary to add a lens for forming parallel light in the optical system, and if the size of the light irradiation device is increased. There is

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to appropriately irradiate an irradiation surface with light of a desired intensity while avoiding an increase in the size of a light irradiation device.

The invention according to claim 1 is a light irradiation device, comprising: a light source unit that emits light toward a predetermined position; an optical system, wherein the irradiation optical system is arranged at a position where the light is divergent light or convergent light when viewed along one direction perpendicular to the optical axis; a variable attenuator that changes the intensity of the light by changing the angle of a transparent plate, which is a flat plate whose line is perpendicular to the one direction, with respect to the optical axis; and a variable attenuator arranged between the variable attenuator and the irradiation surface and a focus lens mechanism for arranging the condensing position of the light on the irradiation surface when viewed along the one direction by moving the lens along the optical axis.

The invention according to claim 2 is the light irradiation device according to claim 1, wherein the angle of the transparent plate with respect to the optical axis and the condensing position of the light are arranged on the irradiation surface. A focus control unit that controls the focus lens mechanism using information indicating the relationship with the amount of movement of the lens is further provided.

The invention according to claim 3 is the light irradiation device according to 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 another light-transmitting plate are arranged along the optical axis, and when viewed along the one direction, the light-transmitting plate and the another light-transmitting plate , is a symmetrical posture with respect to a line perpendicular to the optical axis assumed between them.

The invention according to claim 4 is the light irradiation device according to any one of claims 1 to 3, wherein the irradiation optical system has a plurality of element lenses arranged in the one direction. a splitting lens unit for splitting the light into a plurality of light beams by the plurality of element lenses; and a splitting lens unit disposed between the splitting lens unit and the irradiation surface to divide the irradiation area of the plurality of light beams on the irradiation surface. and an overlapping condensing section, wherein the light is condensed inside or near the split lens section when viewed along the one direction, and between the split lens section and the lens of the focus lens mechanism. , the transparent plate of the variable attenuator is arranged.

According to a fifth aspect of the present invention, there is provided a drawing apparatus comprising: the light irradiation device according to any one of the first to fourth aspects; and a spatial light modulator arranged on the irradiation surface of the light irradiation device. a projection optical system for guiding the light spatially modulated by the spatial light modulator onto an object; a moving mechanism for moving the irradiation position of the spatially modulated light on the object; and the irradiation by the moving mechanism. and a control unit for controlling the spatial light modulator in synchronization with the movement of the position.

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.

It is a figure which shows the structure of a drawing device. It is a figure which shows the structure of a light irradiation apparatus. It is a figure which shows the structure of a light irradiation apparatus. It is a figure which shows the intensity distribution of the light on an irradiation surface. It is a figure which shows the optical system using two parallel plates. It is a figure which shows the result of the ray tracing in an optical system. It is a figure which shows the result of the ray tracing in an optical system. It is a figure which shows the result of the ray tracing in an optical system. It is a figure which shows the result of the ray tracing in an optical system. It is a figure for demonstrating the optical path at the time of inserting a parallel plate. 4 is a diagram showing the relationship between the attenuation rate of the variable attenuator, the rotation angle of the variable attenuator, and the amount of movement of the focus lens mechanism; FIG. It is a figure which shows the result of the ray tracing in an optical system. It is a figure which shows the result of the ray tracing in an optical system.

FIG. 1 is a diagram showing the configuration of a drawing apparatus 1 according to one embodiment of the present invention. The drawing device 1 is a direct drawing device that draws a pattern by irradiating a light beam onto the surface of a substrate 9 such as a semiconductor substrate, a resin substrate, a glass substrate, etc., on which a photosensitive material is applied. , flat panel display (FPD) 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 controller 11 . A 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.

The light irradiation device 31 irradiates the spatial light modulator 32 with linear light through the mirror 39 . Details of the light irradiation device 31 will be described later. The spatial light modulator 32 is, for example, a diffraction grating type and reflection type diffraction grating whose depth can be changed. The spatial light modulator 32 is manufactured using semiconductor device manufacturing technology. The diffraction grating type optical 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 emits 1st-order diffracted light and 0th-order diffracted light (0th-order light). Transition. In this manner, spatially modulated light is emitted from the spatial light modulator 32 .

The projection optical system 33 includes a light blocking plate 331 , a lens 332 , a lens 333 , an aperture plate 334 and a focusing lens 335 . The light shielding plate 331 shields part of the ghost light and high-order diffracted light and allows the light from the spatial light modulator 32 to pass through. Lenses 332 and 333 constitute a zoom section. The aperture plate 334 blocks the (±1)th order diffracted light (and higher order diffracted lights) and allows the 0th order diffracted light to pass. Light passing 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 .

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 configurations. The control unit 11 is implemented by, for example, a computer including a CPU, memory, and the like. All or part of the functions of the control unit 11 may be realized by an electric circuit. In the drawing apparatus 1 , the moving mechanism 22 moves the stage 21 to move the irradiation position of the light from the spatial light modulator 32 on the substrate 9 . Also, the control unit 11 controls the spatial light modulator 32 in synchronization with the movement of the irradiation position by the moving mechanism 22 . A desired pattern is thus drawn on the photosensitive material on the substrate 9 .

2 and 3 are diagrams showing the configuration of the light irradiation device 31. FIG. 2 and 3, the direction parallel to the optical axis J1 of the irradiation optical system 5, which will be described later, is shown as the Z direction, and the directions perpendicular to the Z direction and perpendicular to each other are shown as the X direction and the Y direction (hereinafter as well). 2 shows the configuration of the light irradiation device 31 viewed along the Y direction, and FIG. 3 shows the configuration of the light irradiation device 31 viewed along the X direction.

The light irradiation device 31 shown in FIGS. 2 and 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 , each light source section 4 having 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 units 4 are arranged approximately in the X direction on a plane parallel to the ZX plane (hereinafter referred to as "light source arrangement plane"). A laser beam emitted from each light source 41 is collimated by a 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, the positions on the irradiation optical system 5 irradiated with the laser beams from the plurality of light source units 4 can be approximately matched. In this way, in the light source unit 40, the plurality of light source units 4 arranged on the light source arrangement surface illuminate the same position (divided lens unit 62 described later) on the irradiation optical system 5 from mutually different directions along the light source arrangement surface. A laser beam is emitted toward.

The irradiation optical system 5 is arranged at the irradiation position of the laser light from the light source unit 40 . The irradiation optical system 5 irradiates the laser light along the optical axis J1 on the surface of the spatial light modulator 32 (indicated by the solid line with reference numeral 320 in FIGS. 2 and 3). leads to the surface of the lattice element of As described above, the light from the light irradiation device 31 is irradiated onto the spatial light modulator 32 via the mirror 39. Therefore, the light irradiation device 31 actually includes the mirror 39 as a component, but is shown in FIG. 2 and 3, the mirror 39 is omitted for convenience of illustration (the same applies hereinafter).

The irradiation optical system 5 includes a cylinder lens 611 , a division lens section 62 , an optical path length difference generation section 63 , a cylinder lens 641 , a condensing section 65 and a focus lens mechanism 67 . In the irradiation optical system 5 , from the light source unit 40 toward the irradiation surface 320 , the cylinder lens 611 , the split lens section 62 , the optical path length difference generation section 63 , the cylinder lens 641 , the condensing section 65 , and the focus lens mechanism 67 are arranged in this order. is arranged along the optical axis J1.

Cylinder lens 611 has positive power only in the Y direction. The divided lens unit 62 includes a plurality of lenses 620 (hereinafter referred to as (referred to as “element lens 620”). The divided lens portion 62 is a so-called fly-eye lens. Each element lens 620 has a substantially block shape, and has a first lens surface which is a surface located on the (−Z) side (cylinder lens 611 side) and a surface located on the (+Z) side (optical path length difference generation unit 63 side). and a second lens surface that is a surface that faces the lens. 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 located at the focal point of the second lens surface, and the second lens surface is located 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 plurality of element lenses 620 stacked in the X direction may be formed as a continuous member, or the plurality of individually formed element lenses 620 may be joined together.

The optical path length difference generator 63 includes a plurality of translucent parts 630 densely arranged at a constant pitch in a direction (X direction) perpendicular to the optical axis J1 and along the light source arrangement surface. In the example of FIG. 2, the number of translucent portions 630 in the optical path length difference generating portion 63 is less than the number of element lenses 620 in the divided lens portion 62 by one. Also, the arrangement pitch of the translucent portions 630 is equal to the arrangement pitch of the element lenses 620 . Each translucent portion 630 is block-shaped and has surfaces perpendicular to the X, Y, and Z directions. The plurality of translucent portions 630 aligned in the X direction have the same length in the X direction and the Y direction, but different lengths in the Z direction, that is, in the optical axis J1 direction. As such, the plurality of translucent portions 630 have different optical path lengths.

In the example of FIG. 2, among the plurality of light transmitting portions 630, the light transmitting portion 630 located on the (+X) side has a smaller length in the optical axis J1 direction. The lengths of the plurality of translucent portions 630 in the direction of the optical axis J1 do not necessarily have to be successively longer (or shorter) along the X direction, and may have any uneven shape. In the present embodiment, the plurality of translucent portions 630 in the optical path length difference generating portion 63 are made of the same material and formed as a continuous member. In the optical path length difference generating section 63, a plurality of individually formed translucent sections 630 may be joined together.

Cylinder lens 641 has negative power only in the Y direction. The condensing section 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 . Details of the variable attenuator 66 will be described later. The focus lens mechanism 67 has a cylinder lens 671 and a lens moving mechanism 672 . Cylinder lens 671 has 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.

When viewed along the Y direction as shown in FIG. 2, the collimated laser beams from the plurality of light source units 4 pass through the cylinder lens 611 and enter the split lens unit 62 in a state of parallel light. Light from the light source unit 40 is divided in the X direction by the plurality of element lenses 620 . At this time, the parallel light from each light source unit 4 is incident on the first lens surface of each element lens 620 and condensed on or near the second lens surface. The light (plurality of light beams) split by the plurality of element lenses 620 is emitted from the second lens surface such that the principal ray is parallel to the optical axis J1. The light flux emitted from each element lens 620 enters the optical path length difference generator 63 while diverging.

The divided lens portion 62 and the optical path length difference generating portion 63 are arranged close to each other in the Z direction, and in the X direction, a plurality of element lenses 620 and a plurality of translucent portions 630 except for the element lens 620 closest to the (+X) side. are placed at the same position. Therefore, a plurality of light beams that have passed through these element lenses 620 are transmitted through a plurality of translucent portions 630 respectively. Note that the luminous flux that has passed through the element lens 620 closest to the (+X) side does not pass through any of the translucent portions 630 . In the optical path length difference generating section 63 , the same number of light transmitting sections 630 as the number of element lenses 620 in the divided lens section 62 may be provided. In this case, light that has passed through the plurality (all) of the element lenses 620 is incident on the plurality of translucent portions 630 .

A plurality of light beams that have passed through the optical path length difference generator 63 (including light beams that do not pass through any of the light transmitting portions 630 ) pass through the cylinder lens 641 , the first imaging lens 651 , the variable attenuator 66 and the second imaging lens 652 . pass in order. When viewed along the Y direction, the plurality of light beams emitted from the second imaging lens 652 are converted into substantially parallel rays by the action of the condensing section 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 plurality of light fluxes emitted from the plurality of element lenses 620 are wholly overlapped on the irradiation surface 320 . As described, spatial light modulators 32 are positioned in illuminated surface 320 . In FIGS. 2 and 3, the irradiation area 50 is indicated by a thick solid line.

The irradiation area 50 has a constant width in the X direction. As described above, the plurality of light beams emitted from the plurality of element lenses 620 pass through the light transmitting portions 630 different from each other. length difference occurs. Therefore, it is possible to suppress (or prevent) the occurrence of interference fringes on the irradiation surface 320 due to the interference of the light split by the plurality of element lenses 620 . As a result, as shown in the upper part of FIG. 4, the light intensity distribution in the X direction on the irradiation surface 320 becomes uniform. In each combination of two light-transmitting portions 630 out of the plurality of light-transmitting portions 630, the difference in the optical path length of the light flux passing through the two light-transmitting portions 630 is the coherence of the laser light emitted from the light source portion 4. It is preferable that the distance is greater than or equal to the distance.

When viewed along the X direction as shown in FIG. 3 , the parallel light from the light source unit 40 is converged by the cylinder lens 611 and enters the split lens section 62 . The light is condensed on or near the first lens surface of the element lens 620 (either inside or outside the element lens 620) and emitted as parallel light from the second lens surface. The light passing through the optical path length difference generator 63 becomes 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 order. The light emitted from the second imaging lens 652 becomes 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. .

Light emitted from the cylinder lens 671 is condensed on the irradiation surface 320 . Therefore, on the irradiation surface 320, the irradiation area 50 of the light from each element lens 620 has a line shape extending in the X direction. As a result, line illumination light is obtained, which is a collection of light that has passed through the plurality of element lenses 620, and whose cross section on the irradiation surface 320 (that is, the light beam cross section perpendicular to the optical axis J1) extends in the X direction. be done. 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, ten and several μm, and the width in the X direction is, for example, several tens of mm.

Next, 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 normals to both principal surfaces are perpendicular to the X direction. For example, the main surfaces of the transparent plates 661 and 662 are coated with a dielectric multilayer film or the like whose transmittance changes depending on the incident angle.

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 to each of the transparent plates 661 and 662 and the optical axis J1 when viewed along the X direction is referred to as the "rotational angle". At the initial positions of the transparent plates 661 and 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 non-backlash gear or the like, and rotate at the same angle in different rotating directions. rotate only. Therefore, the first light-transmitting plate 661 and the second light-transmitting plate 662 form a line K1 perpendicular to the optical axis J1 (indicated by a chain double-dashed line in FIG. 3) assumed to be in the center between them in the direction of the optical axis J1. ), the posture is always symmetrical. The intensity of light passing through the variable attenuator 66 can be changed by changing the angle (that is, rotation angle) of the first light-transmitting plate 661 and the second light-transmitting plate 662 with respect to the optical axis J1.

As described above, the variable attenuator 66 is arranged at a position where the light is 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 condensing position in the vicinity of the irradiation surface 320 along the X direction changes to the optical axis J1. move in a direction (shift). A phenomenon in which the condensing position shifts in the direction of the optical axis J1 due to the rotation of the transparent plates 661 and 662 will be described below.

FIG. 5 is a diagram showing an optical system 81 using two parallel plates 811. As shown in FIG. In the optical system 81 of FIG. 5, the light from the object plane 810 is guided to the image plane 819 by the lens 812, and the position between the lens 812 and the image plane 819, that is, the position where the light becomes converging light, Two parallel plates 811 are arranged. The two parallel plates 811 correspond to the first transparent plate 661 and the second transparent plate 662 of the variable attenuator 66 . The focal length of the lens 812 is f=60 mm. In FIG. 5, the horizontal direction is the Z direction, the vertical direction is the Y direction, and the direction perpendicular to the paper surface is the X direction.

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

7A and 7B are diagrams showing the results of ray tracing in the optical system 81 when two parallel plates 811 are rotated in different rotation directions and the rotation angle is 30°. Figures 7A and 7B correspond to Figures 6A and 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 with FIG. 7B, the ray group thickness at reference plane 818 in FIG. 7B is greater than the ray group thickness at image plane 819 in FIG. 6B. That is, in FIG. 7B, the focal point is shifted to the (+Z) side with respect to the reference plane 818 corresponding to the image plane 819 in FIG. 6B. In the examples of FIGS. 6B and 7B, the position of the best focus point (or best image plane) has moved from 77.268 mm to 77.837 mm.

In the case of FIGS. 7A and 7B, in order to return the focal point to the original position (the position of the reference surface 818) without changing the object-image distance, the lens 812 must be moved to the object side ((-Z) side). ) must be moved. In this case, the NA on the imaging side changes, the magnification changes, and the imaging position (Y direction) of the off-axis object also changes.

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

(Number 1)
PP′=(1−1/n)・d
Assuming that the lateral magnification of the imaging system in FIG. 8 ^is M, the longitudinal magnification is ^M2 . The image plane can be moved to the in-focus position when the parallel plate 821 is not present. In the case of FIGS. 7A and 7B, the thickness of one parallel plate 811 is assumed to be D, and the rotation of the parallel plate 811 by the rotation angle .theta. Z-direction length above) changes from 2D to 2D/cos(θ), and the imaging position changes accordingly. As for the effect of inserting the parallel plate 811 into the optical path, spherical aberration, coma aberration, curvature of field, astigmatism, distortion aberration, etc. are affected. It is preferable to take design measures so as to reduce practical effects.

In the optical system 81, the structure in which the object side and the imaging side are interchanged becomes the structure used for the irradiation optical system 5 in FIGS. 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. In addition, when viewed along the X direction as shown in FIG. When the substantial thickness d in Equation 1 changes due to the rotation of the light-transmitting plates 661 and 662 in the variable attenuator 66, in FIG. The state of substantially parallel light on the (+Z) side from the 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 uniformity of the intensity of the line illumination light on the illumination surface 320 is less affected. In practice, the width of the line illumination light in the X direction changes, but by designing to illuminate a wider range than the modulatable region on the surface of the spatial light modulator 32, no practical problem occurs.

On the other hand, in FIG. 3 viewed along the X direction, the condensing position shifts in the direction of the optical axis J1 due to the change in the substantial thickness d of the transparent plates 661 and 662 . In order to ensure the accuracy of pattern drawing in the drawing apparatus 1 , it is necessary to arrange the condensing position on the surface of the spatial light modulator 32 . Therefore, in the irradiation optical system 5, the cylinder lens 671 of the focus lens mechanism 67 is moved back and forth along the optical axis J1 to arrange the light collection position on the irradiation surface 320 in order to eliminate the deviation of the light collection position. An operation, that is, an operation of focusing on the surface of the spatial light modulator 32 is performed. 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 is true when they are arranged at positions where the light is converging.

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

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 amount of movement of the focus lens mechanism 67. As shown in FIG. 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 angles of the transparent plates 661 and 662 . The amount of movement of the focus lens mechanism 67 is the amount of movement of the cylinder lens 671 in the Z direction from a predetermined reference position in order to arrange the light condensing position on the irradiation surface 320 when viewed along the X direction. indicates A 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 a line L2 indicates the relationship between the attenuation rate of the variable attenuator 66 and the movement amount of the focus lens mechanism 67. show. These relationships can be obtained through experiments, calculations, and the like. Note that the values on the left and right vertical axes in FIG. 9 indicate values related to the number of pulses of the motor. 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.

In the light irradiation device 31 of FIG. 1, the 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 the focus control unit 52 in advance. The rotation angle-movement amount information 521 can be derived from FIG. 9, for example. The rotation angle-movement amount information 521 may be an approximate expression or a table.

When a pattern is drawn by the drawing apparatus 1, the drive current value of each light source (LD) 41 is kept constant, and a constant heat generation state is maintained. The control unit 11 in FIG. 1 sets the exposure amount according to the sensitivity of the photosensitive material on the substrate 9 . Also, the moving speed of the substrate 9 by the moving mechanism 22 is set. An attenuation rate required in the variable attenuator 66 is obtained from the set value of the exposure amount and the set value of the movement speed, and the set value of the rotation angle of the variable attenuator 66 is determined accordingly. Note that the relationship between the exposure amount to the substrate 9, the moving speed of the substrate 9, and the rotation angle of the variable attenuator 66 is obtained in advance, and the setting value of the exposure amount and the moving speed setting value of the variable attenuator 66 are obtained. A setting value for the rotation angle may be determined.

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 variable attenuator 66 is controlled by the attenuator control section 51, and the rotation angles of the transparent plates 661 and 662 are adjusted to the set values. Further, 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 condensing position of the light viewed along the X direction is arranged on the irradiation surface 320 . When actually drawing a pattern, the pattern is drawn on the substrate 9 by controlling the spatial light modulator 32 while continuously moving the substrate 9 at the set value of the moving speed.

When fine patterning or alignment is required, after the light transmitting plates 661 and 662 are rotated and the cylinder lens 671 is moved, an imaging unit or the like provided on the stage 21 detects the light beam optically. Images are preferably detected. In this case, by adjusting the control timing of the plurality of grating elements in the spatial light modulator 32 based on the optical image, the width and irradiation position of the irradiation area on the stage 21, and the line illumination light on the irradiation surface 320 It is possible to correct the influence of the inclination of

Here, a light irradiation device of a comparative example is assumed which uses a variable attenuator to irradiate an irradiation surface with light of desired intensity. Since the variable attenuator is usually arranged at a position where light is parallel light, 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 is long, and the size is increased. Further, in the light irradiation device of the comparative example, when the variable attenuator is arranged at a position where the light is divergent light, as described with reference to FIGS. 6B and 7B, the rotation angle of the transparent plate By changing , the condensing position of the light that has passed through the translucent plate changes. As a result, the light cannot be properly collected on the irradiation surface.

On the other hand, in the light irradiation device 31 of FIGS. 2 and 3, the irradiation optical system 5 includes a variable attenuator 66 and a focus lens mechanism 67 . The variable attenuator 66 is arranged at a position where light diverges when viewed along one direction perpendicular to the optical axis J1, and is a flat plate whose normals to both principal surfaces are perpendicular to the one direction. By changing the angle of the transparent plates 661 and 662 with respect to the optical axis J1, the intensity of the light is changed. Further, the focus lens mechanism 67 moves the cylinder lens 671 arranged between the variable attenuator 66 and the irradiation surface 320 along the optical axis J1, so that when viewed along the one direction, the A light condensing position is arranged on the irradiation surface 320 .

Thus, by arranging the variable attenuator 66 at a position where the light is not collimated, the degree of freedom in optical design increases, and a design that increases the overall length of the irradiation optical system 5 is avoided. 31 can be avoided. Thereby, the light irradiation device 31 can be made lightweight and compact. In addition, the focus lens mechanism 67 moves the cylinder lens 671 in accordance with the rotation angle of the light transmitting plates 661 and 662, so that the condensing position can be arranged on the irradiation surface 320. FIG. As a result, the irradiation surface 320 can be appropriately irradiated with light of desired intensity. The drawing apparatus 1 having the light irradiation device 31 described above can draw a pattern with high precision and achieve good exposure quality.

Preferably, the light irradiation device 31 further includes a focus control section 52 . The focus control unit 52 receives information (the above processing In the example, the rotation angle-movement amount information 521) is used to control the focus lens mechanism 67. FIG. This makes it possible to easily arrange the condensing position of the light whose intensity has been changed to the desired intensity on the irradiation surface 320 .

Preferably, the irradiation optical system 5 includes a split lens section 62 and a condensing section 65 . The split lens section 62 has a plurality of element lenses 620 arranged in the one direction, and splits the light into a plurality of light fluxes by the plurality of element lenses 620 . The condensing part 65 is arranged between the split lens part 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 portion 62, and between the split lens portion 62 and the cylinder lens 671 of the focus lens mechanism 67, the variable attenuator 66 Translucent plates 661 and 662 are arranged.

Thus, by arranging the light transmitting plates 661 and 662 of the variable attenuator 66 at the position where the light diverges after passing through the split lens portion 62, the light becomes parallel light like the light irradiation device of the comparative example. Compared to a design in which a position is provided and a variable attenuator is arranged at that position, the size of the light irradiation device 31 can be greatly reduced. The position inside or near the split lens portion 62 where the light is condensed when viewed along the one direction is, for example, when the light passing through the split lens portion 62 crosses the edge of the split lens portion 62. Any position that does not pass (cannot be kicked) is acceptable.

As described above, even when the light-transmitting plates 661 and 662 are arranged at a position where the light converges when viewed along the X direction, the rotation of the light-transmitting plates 661 and 662 converges the light. The position is shifted in the direction of the optical axis J1. Therefore, when the light-transmitting plates 661 and 662 are arranged at positions where the light is diverging or converging when viewed along the X direction, the light condensing position is arranged on the irradiation surface 320. A focus lens mechanism 67 is required. From the viewpoint of reducing the deviation of the condensing position due to the rotation of the light-transmitting plates 661 and 662, the thickness of each of the light-transmitting plates 661 and 662 is preferably as thin as possible, for example, less than 5 mm.

Next, a case where the light condensing position near the irradiation surface 320 shifts 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, the magnification changes, and if the object is displaced from the optical axis, the imaging position in the Y direction also shifts. become. In FIG. 10A, the result of ray tracing for the first object placed on the optical axis J2 in the optical system 81 is denoted by R1, and the first object placed slightly off the optical axis J2 to the (-Y) side. The result of ray tracing for the object No. 2 is labeled R2. Also, FIG. 10B shows the case where the lens 812 is slightly shifted to the (-Y) side in accordance with the deviation of the second object from the optical axis J2. In FIG. 10B, the ray tracing result for the first object placed on the optical axis J2 is denoted by R3, and the second object placed slightly shifted to the (−Y) side from the optical axis J2 The result of ray tracing is labeled R4. 10A and 10B, the rotation angle of the parallel plate 811 is fixed at 0°.

As is clear from FIGS. 10A and 10B, the movement of the lens 812 moves the light converging position with respect to the second object downward. In the irradiation optical system 5 of FIG. 3, even if the imaging position shifts in the Y direction due to the rotation of the transparent plates 661 and 662, the imaging position can be adjusted by moving the cylinder lens 671 in the focus lens mechanism 67 in the Y direction. can be modified. Therefore, in the preferred focus lens mechanism 67, the cylinder lens 671 can also be moved in the Y direction by the lens moving mechanism 672. FIG. Further, when the condensing position at the entrance of the split lens section 62 is shifted in the Y direction, the condensing position is also shifted in the Y direction with respect to the optical axis J1 on the surface (irradiation surface 320) of the spatial light modulator 32. It will be. In this case also, the deviation can be corrected by moving the cylinder lens 671 in the Y direction. Since the optical performance deteriorates due to the movement of the cylinder lens 671 in the Y direction, this method is used as a correction function within a practically acceptable range.

By the way, 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 emitting point of the LD moves, and the concentration on the surface of the spatial light modulator 32 changes. Light position may change. Also, the movement of the LD emission point can occur in any of the X, Y and Z directions. Therefore, if the lens of the focus lens mechanism 67 has power not only in the Y direction but also in the X direction, the above method of moving the lens can also be applied in the X direction. In this way, as a correction method when the light emitting point of the LD is moved, it is possible to use a method of moving the lens of the focus lens mechanism 67 in the X, Y and Z directions.

Various modifications are possible for the light irradiation device 31 and the drawing device 1 described above.

In the above embodiment, two light transmitting plates 661 and 662 are provided in the variable attenuator 66, but depending on the design of the light irradiation device 31, one or three or more light transmitting plates may be provided. On the other hand, in the variable attenuator, by rotating the two light transmitting plates 661 and 662 by the same angle in different rotating directions, the deviation of the optical paths passing through the two light transmitting plates 661 and 662 is reduced. Therefore, the variable attenuator 66 preferably has two transparent plates 661 and 662 of similar construction. In this case, the two light-transmitting plates 661 and 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 and 662 both A symmetrical posture is maintained with respect to a line perpendicular to the optical axis J1 assumed between them. As a result, the shift of the optical path in the variable attenuator 66 can be reduced, and the amount of movement of the cylinder lens 671 of the focus lens mechanism 67 can be reduced. The same applies to the case where two or more light-transmitting plate pairs are provided with the two light-transmitting plates 661 and 662 as a light-transmitting plate pair.

As already mentioned, 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 cylinder lens. Also, the movement amount of the cylinder lens 671 may be specified without using the rotation angle-movement amount information 521 . The position (movement amount) of the cylinder lens 671 in the direction of the optical axis J1 is, for example, an optical It may be determined based on the image.

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

The number of light source units 4 may be one. On the other hand, in the 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 greatly restricted. , it can be said that it is suitable for the light irradiation device 31 having a plurality of light source units 4 . A light source other than a semiconductor laser (LD), such as an LED, may be used in the light source unit 4 .

In the drawing apparatus 1, the spatial light modulator 32 arranged on the irradiation surface 320 of the light irradiation device 31 may be other than a diffraction grating type light modulator. utensils may be used.

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

An object on which drawing is performed by the drawing apparatus 1 may be a substrate other than a semiconductor substrate, a resin substrate, and a glass substrate, or may be other than a substrate. The light irradiation device 31 may be used in addition to the drawing device 1 .

The configurations in the above embodiment and each modified example may be combined as appropriate as long as they do not contradict each other.

REFERENCE SIGNS LIST 1 writing device 4 light source unit 5 irradiation optical system 9 substrate 11 control unit 22 moving mechanism 31 light irradiation device 32 spatial light modulator 33 projection optical system 50 irradiation area 52 focus control unit 62 division lens unit 65 light collecting unit 66 variable attenuator 67 Focus lens mechanism 320 Irradiation surface 521 Rotation angle-movement amount information 620 Element lenses 661, 662 Translucent plate 671 Cylinder lens J1 Optical axis (of irradiation optical system)

Claims (5)

A light irradiation device,
a light source unit that emits light toward a predetermined position;
an irradiation optical system arranged at the predetermined position and guiding the light to an irradiation surface along an optical axis;
with
The irradiation optical system is
The flat plate is arranged at a position where the light is divergent light or convergent light when viewed along one direction perpendicular to the optical axis, and the normals of both principal surfaces are perpendicular to the one direction. a variable attenuator that changes the intensity of the light by changing the angle of the transparent plate with respect to the optical axis;
By moving the lens arranged between the variable attenuator and the irradiation surface along the optical axis, the condensing position of the light is shifted on the irradiation surface when viewed along the one direction. a focus lens mechanism to be placed in the
A light irradiation device comprising: The light irradiation device according to claim 1,
The focus lens mechanism is controlled using information indicating the relationship between the angle of the transparent plate with respect to the optical axis and the amount of movement of the lens for arranging the condensing position of the light on the irradiation surface. A light irradiation device, further comprising a focus control unit. 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,
In the variable attenuator, the light-transmitting plate and the another light-transmitting plate are arranged along the optical axis, and when viewed along the one direction, the light-transmitting plate and the another light-transmitting plate is symmetrical with respect to a line perpendicular to the optical axis assumed between them. The light irradiation device according to any one of claims 1 to 3,
The irradiation optical system is
a split lens unit having a plurality of element lenses arranged in the one direction and splitting the light into a plurality of light fluxes by the plurality of element lenses;
a condensing unit disposed between the divided lens unit and the irradiation surface and overlapping the irradiation areas of the plurality of light beams on the irradiation surface;
with
When viewed along the one direction, the light is condensed inside or near the split lens section, and the transmission of the variable attenuator is provided between the split lens section and the lens of the focus lens mechanism. A light irradiation device comprising a light plate. A drawing device,
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 movement mechanism for moving the irradiation position of the spatially modulated light on the object;
a control unit that controls the spatial light modulator in synchronization with movement of the irradiation position by the moving mechanism;
A rendering device comprising:

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