Drawing device, correction information generating device, drawing method, and correction information generating method

Abstract

This improves drawing accuracy by suppressing optical axis deviation that occurs when adjusting the projection magnification. [Solution] A first optical element group 51 adjusts the projection magnification of a projection optical system 45 by displacing it along an optical axis J1. A second optical element group 52 displaces it to displace the optical axis J1 in a direction perpendicular to the optical axis J1. A storage unit stores correction information indicating the relationship between the projection magnification and the displacement of the second optical element group 52 required to offset the optical axis misalignment. The optical axis misalignment is the deviation of the optical axis J1 from a reference optical axis that occurs when the first optical element group 51 is displaced during adjustment of the projection magnification. A drawing control unit displaces the second optical element group 52 based on the projection magnification of the projection optical system 45 and the correction information to offset the optical axis misalignment during adjustment of the projection magnification. This suppresses the optical axis misalignment that occurs during adjustment of the projection magnification of the projection optical system 45, thereby improving drawing accuracy.

Description

[Technical Field]

[0001] The present invention relates to a technique for generating correction information for a projection optical system that guides light to an object and projects an image, and a technique for using the correction information to irradiate a substrate with light and draw a pattern. [Background technology]

[0002] Conventionally, when drawing a pattern on a printed circuit board, a semiconductor board, or the like (hereinafter referred to as a "board"), a drawing device has been used that irradiates a photosensitive material formed on the board with modulated light and scans the irradiated area of ​​the light to directly draw the pattern.

[0003] In such drawing devices, the optical axis of the optical system may deviate from the reference optical axis during drawing due to beam fluctuations caused by temperature or current fluctuations in the laser diode, which is the light source, or refractive index changes or thermal expansion caused by the optical elements absorbing laser light and generating heat (the so-called thermal lens effect).

[0004] Patent Document 1 proposes a method for detecting and suppressing such fluctuations in the optical axis during drawing. Specifically, a beam splitter and a parallel plate are provided on the optical path of a direct drawing device, and a position detection sensor is also provided to receive light split by the beam splitter. When the position detection sensor detects fluctuations in the optical axis during drawing in the direct drawing device, the parallel plate is rotated and tilted to cancel out the fluctuations in the optical axis. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-128162 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the above-described drawing apparatus is usually provided with a magnification adjustment unit (so-called zoom mechanism) that changes the projection magnification of the projection optical system to accommodate shrinkage of the substrate due to pre-processing, etc. When the magnification adjustment unit adjusts the projection magnification, a lens included in the projection optical system is moved in a movement direction parallel to the reference optical axis (i.e., the design optical axis) of the projection optical system. However, it is not easy to make the movement direction of the lens strictly parallel to the reference optical axis of the projection optical system, considering the limits of the processing accuracy of the components that make up the projection optical system. If the movement direction of the lens is deviated from a direction parallel to the reference optical axis of the projection optical system, the optical axis of the projection optical system may deviate from the reference optical axis when the magnification is adjusted, which may result in a deviation of the drawing position on the substrate (i.e., the beam irradiation position).

[0007] In recent years, with the trend toward higher resolution patterns drawn on substrates, there has been a demand for improved positional accuracy in drawing. Therefore, there is a need to suppress the optical axis deviation that accompanies the adjustment of the projection magnification as described above. However, if an attempt is made to detect and suppress the optical axis deviation during drawing, as in Patent Document 1, it is necessary to provide a beam splitter and a position detection sensor in the optical system of the drawing device, which may complicate the optical system.

[0008] The present invention has been made in view of the above-mentioned problems, and has as its object to improve drawing accuracy by suppressing optical axis deviation that occurs when adjusting the projection magnification. [Means for solving the problem]

[0009] A first aspect of the present invention is a drawing apparatus that draws a pattern by irradiating a substrate with light, the drawing apparatus comprising: a stage that holds the substrate; a drawing head that irradiates the substrate with modulated light; a stage movement mechanism that moves the stage relative to the drawing head in a scanning direction parallel to the top surface of the substrate; a drawing control unit that controls the drawing head; and a memory unit. The drawing head comprises a light modulation unit that modulates light emitted from a light source unit; and a projection optical system that guides the light modulated by the light modulation unit to the substrate. The projection optical system comprises a first optical element group for magnification adjustment that adjusts the projection magnification of the projection optical system by displacing it along an optical axis; and a second optical element group for optical axis position adjustment that displaces the optical axis in a direction perpendicular to the optical axis by displacing it. The memory unit stores correction information indicating the relationship between the projection magnification and the displacement of the second optical element group required to offset the optical axis shift, which is the deviation of the optical axis from a reference optical axis that occurs due to the displacement of the first optical element group when adjusting the projection magnification. The imaging control unit displaces the second optical element group based on the projection magnification of the projection optical system and the correction information, and offsets the optical axis deviation when adjusting the projection magnification.

[0010] Aspect 2 of the present invention is a drawing device of aspect 1, wherein the second optical element group includes a first parallel plate that displaces the optical axis in a first direction perpendicular to the optical axis, and a second parallel plate that displaces the optical axis in a second direction perpendicular to the optical axis and the first direction.

[0011] A third aspect of the present invention is the drawing device of the first or second aspect, further comprising an imaging unit that captures an image of a mark on the substrate, and a deformation acquisition unit that acquires deformation of the substrate based on the image captured by the imaging unit. The drawing control unit displaces the second optical element group based on the deformation of the substrate acquired by the deformation acquisition unit, thereby displacing the optical axis in response to the displacement of the drawing position due to the deformation of the substrate.

[0012] A fourth aspect of the present invention is a drawing device according to the third aspect, wherein the drawing control unit displaces the second optical element group to displace the optical axis based on the projection magnification of the projection optical system and the correction information, even when adjusting the projection magnification, which becomes necessary by displacing the optical axis in accordance with deformation of the substrate.

[0013] A fifth aspect of the present invention is a drawing device according to the third aspect (which may be either the third or fourth aspect), wherein the drawing control unit corrects the drawing data used to draw a pattern when the deformation of the substrate acquired by the deformation acquisition unit is greater than or equal to a predetermined upper deformation limit.

[0014] A sixth aspect of the present invention is the imaging device of the first or second aspect (or any one of the first to fifth aspects), further comprising: another imaging head having the same structure as the imaging head; and an irradiation position measurement unit that measures the irradiation positions of light from the imaging head and the other imaging head. The storage unit further stores the correction information related to the other imaging head. The imaging control unit also cancels out the optical axis misalignment that occurs when adjusting the projection magnification of the other imaging head. The imaging control unit calculates an irradiation position interval, which is the distance between the irradiation position of the imaging head and the irradiation position of the other imaging head, based on the measurement result by the irradiation position measurement unit, and displaces the second optical element group of the imaging head to displace the optical axis of the imaging head so that the irradiation position interval becomes a desired interval.

[0015] A seventh aspect of the present invention provides a correction information generation device that generates correction information for a projection optical system that guides light to an object and projects an image, the correction information generation device comprising: a correction jig that is inserted onto the optical axis of the projection optical system and receives a portion of the light guided by the projection optical system; and a correction information generation unit that generates correction information for the projection optical system based on a light-receiving position on the correction jig. The projection optical system comprises a first optical element group for magnification adjustment that adjusts the projection magnification of the projection optical system by displacing the first optical element group along the optical axis, and a second optical element group for optical axis position adjustment that displaces the optical axis in a direction perpendicular to the optical axis by displacing the second optical element group. The correction information generation unit obtains an optical axis shift, which is a deviation of the optical axis from a reference optical axis that occurs as the first optical element group displaces when adjusting the projection magnification, based on the light-receiving position on the correction jig, and generates the correction information indicating the relationship between the displacement of the second optical element group required to offset the optical axis shift and the projection magnification, based on the relationship between the optical axis shift and the projection magnification.

[0016] An eighth aspect of the present invention is a drawing method for drawing a pattern by irradiating modulated light onto a substrate from a drawing head, the drawing head including a light modulation unit that modulates light emitted from a light source unit and a projection optical system that guides the light modulated by the light modulation unit to the substrate. The projection optical system includes a first optical element group for magnification adjustment that adjusts the projection magnification of the projection optical system by displacing it along an optical axis, and a second optical element group for optical axis position adjustment that displaces the optical axis in a direction perpendicular to the optical axis by displacing it. The drawing method includes the steps of: (a) storing in advance correction information indicating a relationship between the projection magnification and a displacement of the second optical element group required to offset an optical axis shift, which is a deviation of the optical axis from a reference optical axis that occurs as the first optical element group is displaced when the projection magnification is adjusted; and (b) displacing the second optical element group based on the projection magnification of the projection optical system and the correction information, thereby offsetting the optical axis shift when the projection magnification is adjusted.

[0017] A ninth aspect of the present invention is a correction information generation method for generating correction information for a projection optical system that guides light to an object and projects an image, the method comprising: (a) inserting a correction jig onto the optical axis of the projection optical system and extracting and receiving a portion of the light guided by the projection optical system; and (b) generating correction information for the projection optical system based on a light-receiving position on the correction jig. The projection optical system includes a first optical element group for magnification adjustment that adjusts the projection magnification of the projection optical system by displacing it along the optical axis, and a second optical element group for optical axis position adjustment that displaces the optical axis in a direction perpendicular to the optical axis by displacing it. The b) step further comprises: (c) acquiring, based on the light-receiving position on the correction jig, an optical axis shift that is a deviation of the optical axis from a reference optical axis that occurs as the first optical element group displaces when adjusting the projection magnification; and (d) generating the correction information indicating the relationship between the displacement of the second optical element group required to offset the optical axis shift and the projection magnification, based on the relationship between the optical axis shift and the projection magnification. [Effects of the Invention]

[0018] In the present invention, it is possible to improve the drawing accuracy by suppressing the optical axis deviation that occurs when the projection magnification is adjusted. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view showing a drawing device according to an embodiment; [Figure 2] FIG. 2 is a diagram showing the internal structure of a drawing head. [Figure 3] FIG. 4 is an enlarged perspective view showing a second optical element group. [Figure 4] FIG. 1 illustrates the configuration of a computer. [Figure 5] FIG. 2 is a block diagram showing the functions of a control unit. [Figure 6] 1A to 1C are diagrams showing a flow of pattern writing on a substrate. [Figure 7] FIG. 10 is a diagram showing a part of the flow of pattern drawing. [Figure 8] FIG. 10 is a diagram showing a part of the flow of pattern drawing. [Figure 9] FIG. 10 is a diagram showing a part of the flow of pattern drawing. [Figure 10] FIG. 2 is a side view showing the correction information generating device. [Figure 11] FIG. 10 is a diagram showing a flow of generating correction information. [Figure 12] FIG. 10 is a diagram showing a part of the flow of generating correction information. DETAILED DESCRIPTION OF THE INVENTION

[0020] FIG. 1 is a perspective view showing a drawing apparatus 1 according to one embodiment of the present invention. The drawing apparatus 1 is one of substrate processing apparatuses that perform a predetermined process on a substrate 9. Specifically, the drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating a photosensitive material on the substrate 9 with spatially modulated, approximately beam-like light and scanning the irradiated area of ​​the light over the substrate 9. In FIG. 1, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in FIG. 1, the X direction and the Y direction are horizontal directions that are perpendicular to each other, and the Z direction is a vertical direction (i.e., an up-down direction). The same applies to other figures.

[0021] The substrate 9 is, for example, a printed circuit board having a substantially rectangular flat plate shape. On the (+Z) side main surface (hereinafter also referred to as "top surface 91") of the substrate 9, a resist film formed of a photosensitive material is provided on a copper layer. In the drawing device 1, a circuit pattern is drawn (i.e., formed) on the resist film of the substrate 9. The type and shape of the substrate 9 may be variously changed.

[0022] The imaging device 1 includes a stage 21, a stage moving mechanism 22, an imaging unit 3, an imaging unit 4, a base 61, and a control unit 8. The stage 21, the stage moving mechanism 22, the imaging unit 3, the imaging unit 4, and the base 61 are housed inside a housing (not shown). The control unit 8 is disposed outside the housing and controls the stage moving mechanism 22, the imaging unit 3, the imaging unit 4, etc.

[0023] The stage 21 is a substantially rectangular, flat member located below the imaging unit 3 and the imaging unit 4 (i.e., on the (-Z) side). The stage 21 includes a substrate holder 25 that holds the horizontal substrate 9 from below. The substrate holder 25 is, for example, a vacuum chuck that holds the lower surface of the substrate 9 by suction. The substrate holder 25 may have a structure other than a vacuum chuck, and may be, for example, a mechanical chuck. The upper surface 91 of the substrate 9 placed on the substrate holder 25 is substantially perpendicular to the Z direction and substantially parallel to the X and Y directions.

[0024] The stage moving mechanism 22 is a moving mechanism that moves the stage 21 relatively in the horizontal direction (i.e., in a direction approximately parallel to the upper surface 91 of the substrate 9) with respect to the imaging unit 3 and the drawing unit 4. The stage moving mechanism 22 is attached to the upper surface of the base 61 and is supported from below by the base 61. The base 61 has, for example, an approximately rectangular parallelepiped shape with a length in the Y direction longer than its length in the X direction.

[0025] The stage movement mechanism 22 includes a first movement mechanism 23 and a second movement mechanism 24. The second movement mechanism 24 supports the stage 21 from below and moves the stage 21 linearly in the X direction along the guide rails. The first movement mechanism 23 supports the second movement mechanism 24 from below and moves the stage 21 together with the second movement mechanism 24 linearly in the Y direction along the guide rails.

[0026] The drive sources of the first moving mechanism 23 and the second moving mechanism 24 are, for example, linear servo motors or motors attached to ball screws. The motors or the like that serve as the drive sources of the first moving mechanism 23 and the second moving mechanism 24 move, for example, together with the stage 21. The structures of the first moving mechanism 23 and the second moving mechanism 24 may be modified in various ways.

[0027] The drawing apparatus 1 may be provided with a stage rotation mechanism that rotates the stage 21 around a rotation axis extending in the Z direction. The drawing apparatus 1 may also be provided with a stage lifting mechanism that moves the stage 21 in the Z direction. For example, a servo motor can be used as the stage rotation mechanism. For example, a linear servo motor can be used as the stage lifting mechanism. The structures of the stage rotation mechanism and the stage lifting mechanism may be modified in various ways.

[0028] The imaging unit 3 includes a plurality of imaging heads 31 (two in the example shown in FIG. 1) arranged in the X direction. Each imaging head 31 is supported above the stage 21 and the stage movement mechanism 22 by a support unit 40 that straddles the stage 21 and the stage movement mechanism 22. The support unit 40 is, for example, a single member that is provided at one position in the Y direction. In the example shown in FIG. 1, the support unit 40 is a gate-shaped member (a so-called gantry) when viewed parallel to the Y direction, and is provided upright on the upper surface of a base 61.

[0029] 1, the two imaging heads 31 are attached to the (+Y) side surface of the support part 40. Of the two imaging heads 31, for example, one imaging head 31 is fixed to the support part 40, and the other imaging head 31 is movable in the X direction on the support part 40. This makes it possible to change the distance in the X direction between the two imaging heads 31. Note that the number of imaging heads 31 in the imaging unit 3 may be one, or three or more.

[0030] In the drawing device 1, the imaging heads 31 of the imaging unit 3 capture images of multiple marks on the substrate 9, and alignment of the substrate 9 (i.e., correction of the relative position of the substrate 9 with respect to the drawing heads 41, which will be described later) is performed based on the acquired images of the multiple marks. The marks are, for example, alignment marks. The marks may be, for example, part of a pattern provided on the substrate 9, an edge of the substrate 9, or edges of multiple divided regions set on the substrate 9.

[0031] The imaging unit 4 includes a plurality of imaging heads 41 arranged in the X direction. The plurality of imaging heads 41 (six in the example shown in FIG. 1) have substantially the same structure. Each imaging head 41 includes a spatial light modulator that irradiates modulated (i.e., spatially modulated) light downward. Each imaging head 41 is supported above the stage 21 and the stage movement mechanism 22 by the support unit 40 described above. In the example shown in FIG. 1, the six imaging heads 41 are attached to the (-Y) side of the support unit 40. In other words, the six imaging heads 41 are arranged on the opposite side of the support unit 40 from the two imaging heads 31 described above in the Y direction.

[0032] FIG. 2 is a diagram showing the internal structure of one drawing head 41. In the drawing unit 4, the internal structures of the other drawing heads 41 are substantially the same as that shown in FIG. 2. The drawing head 41 includes a light modulation unit 44, a projection optical system 45, and a frame 47. The light modulation unit 44, the projection optical system 45, and the frame 47 are housed inside a drawing head cover 48. In FIG. 2, to make the drawing easier to understand, a cross section of the drawing head cover 48 is shown by a dashed line, and the internal structure of the drawing head cover 48 is shown by a solid line.

[0033] The frame 47 is a generally columnar member extending generally parallel to the Z direction. The frame 47 is, for example, directly fixed to the support unit 40. Alternatively, the frame 47 is indirectly fixed to the support unit 40 via a drawing head cover 48. The frame 47 supports the light modulation unit 44 and the projection optical system 45.

[0034] The drawing unit 4 further includes a light source unit 42 and an illumination optical system 43. In the example shown in FIG. 2, the light source unit 42 and the illumination optical system 43 are disposed outside the drawing head cover 48. The light source unit 42 includes a light source such as an LED (Light Emitting Diode) or an LD (Laser Diode). Light emitted from the light source unit 42 is guided into the drawing head cover 48 by the illumination optical system 43, which includes optical elements such as multiple lenses. In FIG. 2, the multiple lenses and the like of the illumination optical system 43 are not shown, and the illumination optical system 43 is illustrated as a single rectangle. The light guided into the drawing head cover 48 by the illumination optical system 43 enters the light modulation unit 44 via a mirror 431.

[0035] The light modulation unit 44 is fixed to the upper end (i.e., the end on the (+Z) side) of the frame 47. The light modulation unit 44 includes a spatial light modulator that modulates the light emitted from the light source unit 42. The spatial light modulator is, for example, a DMD (Digital Micromirror Device) in which a plurality of micromirrors are arranged two-dimensionally. Note that the light modulation unit 44 may also include a spatial light modulator other than a DMD (for example, a diffraction grating spatial light modulation element). The light modulation unit 44 modulates the light guided by the illumination optical system 43 and guides the light to the projection optical system 45.

[0036] The projection optical system 45 is disposed on the (-Z) side (i.e., below) of the light modulation unit 44. The projection optical system 45 guides light modulated by the light modulation unit 44 to an upper surface 91 (see FIG. 1) of the substrate 9. The projection optical system 45 includes a plurality of optical elements arranged along an optical axis J1 extending substantially parallel to the Z direction. The plurality of optical elements includes a first optical element group 51 for adjusting magnification, a second optical element group 52 for adjusting the optical axis position, and a third optical element group 53 for autofocus. In the projection optical system 45, the light modulated by the light modulation unit 44 passes through the second optical element group 52, the first optical element group 51, and the third optical element group 53 in this order, and is irradiated onto the upper surface 91 of the substrate 9.

[0037] 2, the plurality of optical elements constituting the projection optical system 45 includes optical elements other than the first optical element group 51, the second optical element group 52, and the third optical element group 53. In addition, in the example shown in Fig. 2, the second optical element group 52 is located closest to the (+Z) side (i.e., the side closest to the light modulation unit 44 in the direction along the optical axis J1) among the plurality of optical elements constituting the projection optical system 45.

[0038] In the example shown in FIG. 2, the first optical element group 51 includes two optical elements 511 and 512 arranged substantially parallel to the Z direction. The optical element 511 is disposed on the (+Z) side of the optical element 512. The optical elements 511 and 512 are each a lens. The optical elements 511 and 512 are each attached to the frame 47 so as to be movable in a movement direction substantially parallel to the Z direction. Element moving mechanisms 513 and 514 that move the optical elements 511 and 512 in the movement direction are provided, for example, inside the frame 47. The element moving mechanisms 513 and 514 are, for example, linear servo motors or motors attached to ball screws. The optical elements 511 and 512 are movable independently of each other.

[0039] In the projection optical system 45, the projection magnification of the projection optical system 45 is adjusted by changing the Z-direction positions of the two optical elements 511, 512 of the first optical element group 51 by the element moving mechanisms 513, 514. That is, the projection magnification of the projection optical system 45 is adjusted by displacing the first optical element group 51 along the optical axis J1. The optical elements 511, 512 of the first optical element group 51 and the element moving mechanisms 513, 514 constitute a magnification adjustment unit 510 (i.e., a zoom mechanism) that adjusts the projection magnification of the projection optical system 45. The number of optical elements included in the first optical element group 51 may be one, or may be three or more.

[0040] The second optical element group 52 is disposed on the (+Z) side of the first optical element group 51. In other words, the second optical element group 52 is disposed between the first optical element group 51 and the light modulation unit 44 in the direction along the optical axis J1. The second optical element group 52 includes one optical element or two or more optical elements. In FIG. 2, the second optical element group 52 is illustrated as a single rectangle. In the projection optical system 45, as the second optical element group 52 is displaced, the optical axis J1 is displaced in a direction perpendicular to the optical axis J1 (i.e., shifted approximately horizontally) while remaining substantially parallel to the Z direction.

[0041] FIG. 3 is an enlarged perspective view of the second optical element group 52. In the example shown in FIG. 3, the second optical element group 52 includes two optical elements 521 and 522 arranged substantially parallel to the Z direction. The optical element 521 is disposed on the (+Z) side of the optical element 522. Each of the optical elements 521 and 522 is a parallel plate (also called a parallel plate substrate), which is a flat optical element with both main surfaces parallel to each other. In a parallel plate, light is incident on one main surface and is emitted from the other main surface. When the parallel plate is disposed perpendicular to the optical axis, the optical axis does not shift between before and after entering and passing through the parallel plate (i.e., it does not displace in a direction perpendicular to the optical axis). On the other hand, when the parallel plate is rotated around a predetermined rotation axis and tilted with respect to the optical axis, the optical axis after passing through the parallel plate shifts from the optical axis before incidence in a direction perpendicular to the rotation axis.

[0042] In the example shown in FIG. 3, both principal surfaces of the optical elements 521 and 522 are planes extending approximately perpendicular to the Z direction. An element rotation mechanism 523 is connected to the (+Y) side of the optical element 521. The element rotation mechanism 523 is, for example, a servo motor. The element rotation mechanism 523 rotates the optical element 521 around a rotation axis 525 extending approximately parallel to the Y direction. When the optical element 521 is inclined with respect to the Z direction, light incident on the optical element 521 is shifted in the X direction as it passes through the optical element 521. In the imaging device 1, the relationship between the rotation amount of the optical element 521 and the shift amount in the X direction is acquired in advance and stored in a storage unit 801 (see FIG. 5), which will be described later.

[0043] An element rotation mechanism 524 is connected to the (+X) side of the optical element 522. The element rotation mechanism 524 is, for example, a servo motor. The element rotation mechanism 524 rotates the optical element 522 around a rotation axis 526 extending substantially parallel to the X direction. When the optical element 522 is tilted with respect to the Z direction, light incident on the optical element 522 is shifted in the Y direction as it passes through the optical element 522. In the imaging device 1, the relationship between the rotation amount of the optical element 522 and the shift amount in the Y direction is acquired in advance and stored in the storage unit 801.

[0044] If the optical elements 521 and 522 of the second optical element group 52 are referred to as the "first parallel plate" and the "second parallel plate," respectively, the first parallel plate displaces the optical axis J1 in a first direction (e.g., the X direction) substantially perpendicular to the optical axis J1 while maintaining the optical axis J1 substantially parallel to the Z direction. The second parallel plate displaces the optical axis J1 in a second direction (e.g., the Y direction) substantially perpendicular to the optical axis J1 and the first direction while maintaining the optical axis J1 substantially parallel to the Z direction.

[0045] The optical elements 521 and 522 of the second optical element group 52 and the element rotation mechanisms 523 and 524 constitute an optical axis displacement unit 520 that displaces the optical axis J1 in a direction substantially perpendicular to the optical axis J1 (i.e., shifts it substantially horizontally) while maintaining the optical axis J1 substantially parallel to the Z direction. In the optical axis displacement unit 520, the rotation of the optical element 521 and / or the optical element 522 is referred to as "displacement of the second optical element group 52." Note that the optical elements included in the second optical element group 52 do not necessarily have to be parallel plates and may be other optical elements. Furthermore, the number of optical elements included in the second optical element group 52 may be one, or may be three or more.

[0046] The third optical element group 53 shown in FIG. 2 is disposed on the (-Z) side (i.e., lower) than the first optical element group 51. In other words, the third optical element group 53 is disposed between the first optical element group 51 and the substrate 9 in the direction along the optical axis J1. The third optical element group 53 includes one or more optical elements such as lenses. In FIG. 2, the third optical element group 53 is shown as a single rectangle. In the example shown in FIG. 2, the third optical element group 53 is an objective lens located closest to the substrate 9 in the direction along the optical axis J1. The third optical element group 53 is attached to the frame 47 so as to be movable in the Z direction. A movement mechanism (not shown) that moves the third optical element group 53 in the Z direction is provided, for example, inside the frame 47.

[0047] In the imaging head 41, a distance sensor (not shown) measures the distance in the Z direction from the substrate 9. Then, based on the measurement result by the distance sensor, the third optical element group 53 is displaced in the Z direction, thereby adjusting the focal position of light emitted from the imaging head 41 toward the substrate 9 (i.e., the position where the image of the micromirror of the DMD of the light modulation unit 44 is formed) in the Z direction so that it is located on the upper surface 91 of the substrate 9. The third optical element group 53, the above-mentioned movement mechanism that displaces the third optical element group 53, and the above-mentioned distance sensor constitute an autofocus mechanism that adjusts the focal position in accordance with fluctuations in the distance between the projection optical system 45 and the substrate 9.

[0048] In the example shown in FIG. 1, the six drawing heads 41 are arranged in a substantially straight line substantially parallel to the X direction. The positions of the six drawing heads 41 in the Y direction and the Z direction are substantially the same. Note that the multiple drawing heads 41 do not necessarily need to be arranged in a straight line, and may be arranged, for example, in a staggered pattern. When the drawing heads 41 are arranged in a staggered pattern, multiple drawing head rows each composed of multiple drawing heads 41 arranged in the X direction are arranged in the Y direction with their positions in the X direction shifted. Furthermore, the drawing unit 4 may have one drawing head 41 or two or more drawing heads 41.

[0049] In the drawing apparatus 1, pattern drawing on the substrate 9 is performed by a so-called multi-pass method. Specifically, while modulated light from the multiple drawing heads 41 of the drawing unit 4 is irradiated onto the upper surface 91 of the substrate 9, the first moving mechanism 23 of the stage moving mechanism 22 moves the substrate 9 in the Y direction to pass below the drawing heads 41. As a result, the irradiation area of ​​the light from the multiple drawing heads 41 is scanned in the Y direction on the substrate 9, and drawing on the substrate 9 is performed.

[0050] Next, the second movement mechanism 24 moves the substrate 9 stepwise by a predetermined distance in the X direction. Then, the first movement mechanism 23 moves the substrate 9 in the Y direction, and the drawing head 41 again irradiates the substrate 9 with light in parallel with this movement, thereby drawing on the substrate 9. In the drawing device 1, the irradiation of light onto the substrate 9 moving in the Y direction and the step movement of the substrate 9 in the X direction are alternately performed, thereby drawing a pattern on the substrate 9.

[0051] In the following description, the Y direction will also be referred to as the "main scanning direction" or "scanning direction," and the X direction will also be referred to as the "sub-scanning direction" or "width direction." The main scanning direction and the sub-scanning direction are directions that are approximately parallel to the upper surface 91 of the substrate 9. In the stage movement mechanism 22, the first movement mechanism 23 is a main scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the main scanning direction. The second movement mechanism 24 is a sub-scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the sub-scanning direction.

[0052] In the drawing apparatus 1, drawing on the substrate 9 may be performed by a single-pass method (also called a one-pass method), in which drawing of a pattern on the substrate 9 is completed by moving the substrate 9 relative to the drawing head 41 only once in the Y direction. In this case, when drawing the pattern, the second moving mechanism 24 does not perform sub-scanning of the substrate 9 (i.e., step movement in the X direction). In other words, the stage moving mechanism 22 is a scanning mechanism that moves the stage 21 relative to the drawing head 41 at least in the scanning direction.

[0053] The stage 21 is provided with a calibration unit 26 located on the (+Y) side of the substrate holding unit 25. The calibration unit 26 includes a scale unit 261, a calibration camera 262, and a camera movement mechanism (not shown). The scale unit 261 is a substantially flat plate-shaped member substantially perpendicular to the Z direction and is provided at substantially the same height as the upper surface of the stage 21. The scale unit 261 is, for example, a substantially rectangular strip-shaped member extending substantially parallel to the X direction and is translucent. A large number of scales indicating the position in the X direction on the upper surface are provided on the upper surface of the scale unit 261. In other words, the scale unit 261 is a translucent scale member. The scale unit 261 is, for example, a substantially transparent glass scale. The scale of the scale unit 261 is, for example, a cross pattern or a pattern of another shape. The scale unit 261 may also be a translucent member.

[0054] The calibration camera 262 is disposed substantially vertically below the scale section 261, facing upward. The calibration camera 262 is, for example, a digital camera having a CCD or CMOS as an imaging element. The type and performance of the calibration camera 262 may be set as appropriate. The camera movement mechanism is a movement mechanism that moves the calibration camera 262 linearly in the X direction along a guide rail (not shown). The drive source of the camera movement mechanism is, for example, a linear servo motor or a motor attached to a ball screw. The structure of the camera movement mechanism may be modified in various ways.

[0055] In the drawing device 1, the calibration camera 262 is moved by the camera movement mechanism, and with the calibration camera 262 positioned below one of the drawing heads 41, the drawing head 41 projects a predetermined calibration pattern onto the scale section 261. The calibration pattern is, for example, a cross-shaped pattern. The shape of the calibration pattern may be changed in various ways. The calibration camera 262 captures an image of the area on the scale section 261 that is irradiated with light from the drawing head 41 (i.e., the calibration pattern), along with the scale, from below. The image acquired by the calibration camera 262 (hereinafter also referred to as an "inspection image") is sent to the control unit 8 and used for calibrating the drawing head 41, which will be described later. The calibration unit 26 similarly acquires inspection images for the other drawing heads 41 and sends them to the control unit 8.

[0056] 4 is a diagram showing the configuration of a computer 800 that functions as the control unit 8. The computer 800 has the configuration of a typical computer system including a CPU 81, a ROM 82, a RAM 83, a fixed disk 84, a display 85, an input unit 86, a reading device 87, a communication unit 88, a GPU 89, and a bus 80. The CPU 81 performs various types of arithmetic processing. The GPU 89 performs various types of arithmetic processing related to image processing. The ROM 82 stores basic programs. The RAM 83 stores various types of information. The fixed disk 84 stores information. The display 85 is a display unit that displays various types of information such as images.

[0057] The input unit 86 includes a keyboard 86a and a mouse 86b that accept input from an operator. The reading device 87 reads information from a computer-readable recording medium 871, such as an optical disk, a magnetic disk, a magneto-optical disk, or a memory card. The display 85, the keyboard 86a, the mouse 86b, and the reading device 87 are connected to the bus 80 via an interface I / F. The communication unit 88 transmits and receives signals to and from devices external to the computer 800. The bus 80 is a signal circuit that connects the CPU 81, the GPU 89, the ROM 82, the RAM 83, the fixed disk 84, the display 85, the input unit 86, the reading device 87, and the communication unit 88.

[0058] In computer 800, program 872 is read in advance from recording medium 871 via reader 87 and stored on fixed disk 84. Program 872 may be stored on fixed disk 84 via a network. CPU 81 and GPU 89 execute arithmetic processing using RAM 83 and fixed disk 84 in accordance with program 872. CPU 81 and GPU 89 function as arithmetic units in computer 800. Other components functioning as arithmetic units may be employed in addition to CPU 81 and GPU 89.

[0059] FIG. 5 is a block diagram showing the functions of the control unit 8 realized by the computer 800 shown in FIG. 5. Components other than the control unit 8 are also shown in FIG. The control unit 8 includes a memory unit 801, an irradiation position acquisition unit 802, a position detection unit 803, a drawing control unit 804, and a deformation acquisition unit 805. The memory unit 801 is realized by the RAM 83, the fixed disk 84, and the like. The memory unit 801 stores in advance various information such as data of a pattern to be drawn on the substrate 9 (i.e., drawing data). The irradiation position acquisition unit 802, the position detection unit 803, the drawing control unit 804, and the deformation acquisition unit 805 are realized by the CPU 81, the GPU 89, the ROM 82, the RAM 83, the fixed disk 84, and their peripheral components.

[0060] Next, drawing of a pattern by the drawing apparatus 1 will be described with reference to FIG. 6. FIG. 6 is a diagram showing an example of the flow of drawing a pattern on a substrate 9. In the drawing apparatus 1 shown in FIG. 1, the projection magnification of the projection optical system 45 (see FIG. 2) of each drawing head 41 is determined in advance according to the type of substrate 9 on which drawing is to be performed and the type of pattern to be drawn, and is stored in a storage unit 801 (see FIG. 5). The projection magnifications of the multiple drawing heads 41 may be the same or different. In addition, correction information, which will be described later, is stored in advance in the storage unit 801 (step S10).

[0061] In the imaging device 1, before imaging on the substrate 9 is started, first, the imaging control unit 804 (see FIG. 5) controls the magnification adjustment unit 510 shown in FIG. 2 to displace the first optical element group 51 so that the projection magnification of the projection optical system 45 of each imaging head 41 becomes the set projection magnification. Specifically, the element moving mechanism 513 and / or the element moving mechanism 514 is driven to displace the optical elements 511 and / or the optical elements 512 of the first optical element group 51 in a movement direction substantially parallel to the Z direction, thereby adjusting the projection magnification of the projection optical system 45 (step S11).

[0062] At this time, the movement direction of the optical elements 511 and 512 is approximately parallel to the reference optical axis (i.e., the design optical axis) of the projection optical system 45. However, due to limitations in the processing accuracy of the components that make up the projection optical system 45, the movement direction of the optical elements 511 and 512 may not be strictly parallel to the reference optical axis. If the movement direction of the optical elements 511 and 512 and the reference optical axis of the projection optical system 45 are not parallel, the displacement of the optical elements 511 and 512 may cause the optical axis J1 of the projection optical system 45 to move horizontally while remaining approximately parallel to the Z direction (i.e., shift in the X direction and / or Y direction), potentially resulting in deviation from the reference optical axis. In the following description, deviation of the optical axis J1 of the projection optical system 45 from the reference optical axis is also referred to as "optical axis deviation." The magnitude of the optical axis deviation varies depending on the positions of the optical elements 511 and 512 (i.e., the projection magnification of the projection optical system 45).

[0063] In the imaging device 1, in each imaging head 41, the optical axis shift that occurs due to the displacement of the first optical element group 51 in step S11 (i.e., the displacement of the optical elements 511 and 512) is offset by displacing the second optical element group 52. When offsetting the optical axis shift, first, the amount of displacement of the second optical element group 52 required to offset the optical axis shift is calculated (step S12). In step S12, the amount of displacement of the second optical element group 52 is calculated based on correction information that is pre-stored in the storage unit 801. The correction information is information that indicates the relationship between the projection magnification of the projection optical system 45 and the displacement of the second optical element group 52 required to offset the optical axis shift corresponding to the projection magnification. A method for acquiring the correction information will be described later.

[0064] For example, when a combination of one projection magnification and one displacement amount of the second optical element group 52 corresponding to the projection magnification (i.e., the rotation amount of each of the optical elements 521 and 522) is considered as one data element, the correction information is stored in the storage unit 801 as a correction table (i.e., a database) including multiple data elements. Alternatively, the correction information may be stored in the storage unit 801 as a correction formula that expresses the displacement amount of the second optical element group 52 using a function with the projection magnification of the projection optical system 45 as a variable.

[0065] In step S12, for example, the imaging control unit 804 obtains the projection magnification of the projection optical system 45 from the storage unit 801 and searches the above-mentioned correction table using the obtained projection magnification as a search key to obtain the displacement amount of the second optical element group 52. If the correction table does not contain a data element including the projection magnification corresponding to the search key, for example, a data element including the projection magnification closest to the search key is extracted. Alternatively, two data elements including the projection magnification closest to the search key and the second closest projection magnification may be extracted, and the displacement amount of the second optical element group 52 may be obtained by linearly interpolating the two data elements. Alternatively, the imaging control unit 804 may obtain the displacement amount of the second optical element group 52 by substituting the projection magnification of the projection optical system 45 into the above-mentioned correction formula.

[0066] When step S12 is completed, the imaging control unit 804 controls the optical axis displacement unit 520 of each imaging head 41, and the second optical element group 52 is displaced by the displacement amount calculated in step S12 (step S13). Specifically, the imaging control unit 804 drives the element rotation mechanism 523 and / or the element rotation mechanism 524, and the optical element 521 and / or the optical element 522 of the second optical element group 52 is rotated by the rotation amount calculated in step S12. As a result, the optical axis J1 of the projection optical system 45 is shifted in the approximately horizontal direction so as to coincide with the reference optical axis, and the above-mentioned optical axis deviation is canceled out.

[0067] After steps S11 to S13 are completed, the first moving mechanism 23 of the stage moving mechanism 22 moves the stage 21 holding the substrate 9 in the (+Y) direction. The stage 21 passes below the multiple imaging heads 31 of the imaging unit 3, and the alignment marks of the substrate 9 on the stage 21, which is moving at a constant speed, are imaged by the imaging heads 31 (step S14). When the alignment marks are imaged, pulsed illumination light (i.e., flashes of light) is irradiated onto the imaging area of ​​the imaging heads 31 from an illumination light source (not shown) provided in the imaging unit 3. After step S14 is completed, the stage 21 waits at a waiting position, which is a position near the end of the first moving mechanism 23 on the (+Y) side.

[0068] The image including the alignment mark acquired in step S14 (hereinafter also referred to as the "captured image") is sent to the control unit 8 and stored in the memory unit 801 (see FIG. 5). Then, the position detection unit 803 acquires the position of the substrate 9 on the stage 21 (i.e., the relative position of the substrate 9 with respect to the stage 21) based on the captured image stored in the memory unit 801 (step S15). Specifically, the position of the substrate 9 on the substrate holder 25 of the stage 21 is determined based on the position of the alignment mark in the captured image.

[0069] The position of the substrate 9 on the stage 21 detected by the position detection unit 803 is sent to the writing control unit 804. The writing control unit 804 determines the amount of deviation of the position of the substrate 9 on the stage 21 from the design position, and determines the amount of deviation of the relative position of the substrate 9 with respect to the writing head 41 from the design position. Furthermore, the writing control unit 804 determines alignment information for correcting the relative position of the substrate 9 with respect to the writing head 41 so that it coincides with the design position, based on the amount of deviation (step S16). The alignment information is, for example, information for correcting the movement of the substrate 9 by the stage movement mechanism 22 when writing a pattern on the substrate 9. Alternatively, the alignment information may be information for correcting writing data of a pattern to be written on the substrate 9 in accordance with the amount of deviation.

[0070] After the acquisition of the alignment information is completed, the drawing control unit 804 drives the stage moving mechanism 22 and the multiple drawing heads 41 of the drawing unit 4 based on the drawing data stored in the storage unit 801, the alignment information, etc. As a result, the stage 21 positioned at the standby position is moved in the (-Y) direction, and the substrate 9 held by the substrate holding unit 25 passes below the multiple drawing heads 41 of the drawing unit 4. Then, modulated light is irradiated from the multiple drawing heads 41 onto the moving substrate 9, and a pattern is drawn on the upper surface 91 of the substrate 9 (step S17).

[0071] In this embodiment, as described above, pattern drawing on the substrate 9 is performed by the multi-pass method, and therefore the substrate 9 moving back and forth in the Y direction below the drawing head 41 is irradiated with modulated light from the drawing head 41 to draw a pattern. In an actual drawing apparatus 1, steps S14 to S17 are performed sequentially on a plurality of substrates 9 to draw a pattern.

[0072] As described above, in the imaging device 1, optical axis misalignment caused by adjustment of the projection magnification of the projection optical system 45 in each imaging head 41 is suppressed, and therefore the positional accuracy of the light irradiation position by each imaging head 41 on the substrate 9 is improved. As a result, the imaging accuracy on the substrate 9 is improved.

[0073] 7, in the imaging device 1, calibration of each imaging head 41 may be performed using the calibration unit 26 before step S11. The calibration is performed for the purpose of correcting, for example, a shift in the light irradiation position caused by an attachment error when the imaging head 41 is attached to the support unit 40, or a shift in the light irradiation position caused by minute deformation of the support unit 40 due to a temperature change.

[0074] When the imaging head 41 is calibrated, first, the above-mentioned test image is acquired by the calibration camera 262 (see FIG. 1) of the calibration unit 26, and is sent to and stored in the memory unit 801 of the control unit 8. Next, the irradiation position acquisition unit 802 determines the position of the calibration pattern in the test image, and acquires the position of light irradiation by the imaging head 41 (step S21). The irradiation position acquisition unit 802 and the calibration unit 26 constitute an irradiation position measurement unit 260 (see FIG. 1) that measures the position of light irradiation by each imaging head 41.

[0075] The light irradiation positions of each drawing head 41 acquired in step S21 (i.e., the measurement results by the irradiation position measurement unit 260) are sent to the drawing control unit 804. Based on the measurement results by the irradiation position measurement unit 260, the drawing control unit 804 calculates the distance in the X direction between each two irradiation positions adjacent in the X direction (hereinafter also referred to as "irradiation position interval") for the multiple drawing heads 41 of each drawing unit 4 (step S22). Furthermore, based on the measurement results by the irradiation position measurement unit 260, the drawing control unit 804 also calculates the deviation in the X direction of the irradiation positions of the multiple drawing heads 41.

[0076] In the imaging device 1, in order to set the above-mentioned irradiation position interval to a desired interval and to eliminate deviation of the irradiation positions in the X direction, the second optical element group 52 is displaced in each imaging head 41, and the optical axis J1 of the projection optical system 45 is displaced. Specifically, first, based on the above-mentioned irradiation position interval and the deviation of the irradiation positions in the X direction, the imaging control unit 804 calculates the amount of displacement of the optical axis J1 necessary to set the irradiation positions of each imaging head 41 to desired positions. Then, the imaging control unit 804 calculates the amount of displacement of the second optical element group 52 (i.e., the amount of rotation of the optical elements 521 and 522) necessary to realize the displacement of the optical axis J1 (step S23).

[0077] Thereafter, the imaging control unit 804 controls the optical axis displacement unit 520 to rotate the optical elements 521 and 522 (i.e., displace the second optical element group 52), thereby displacing the optical axis J1 of the projection optical system 45 of each imaging head 41, and the interval between the irradiation positions of each two adjacent imaging heads 41 in the X direction is set to a desired interval. Furthermore, the irradiation positions of the multiple imaging heads 41 are, for example, arranged at the same position in the X direction (step S24). This allows imaging on the substrate 9 to be performed with the multiple imaging heads 41 maintaining a desired relative positional relationship. As a result, the imaging accuracy on the substrate 9 is improved. Note that in step S24, the second optical element group 52 of all imaging heads 41 does not necessarily need to be displaced; rather, the second optical element group 52 of at least one imaging head 41 is displaced in order to set the above-mentioned interval between the irradiation positions to a desired interval.

[0078] The above-described steps S21 to S24 may be performed in parallel with, for example, steps S11 to S13. Alternatively, step S24 may be omitted, and the displacement amount of the second optical element group 52 calculated in step S23 may be added to the above-described correction table, so that the displacement of the second optical element group 52 in the calibration may be performed simultaneously with the displacement of the second optical element group 52 for offsetting the optical axis shift accompanying the above-described adjustment of the projection magnification (step S13).

[0079] 8, in the drawing device 1, the deformation of the substrate 9 may be acquired by the deformation acquisition unit 805 based on the captured image acquired in step S14 (step S31). The deformation of the substrate 9 may be acquired by various known methods. In the drawing device 1, when the substrate 9 is deformed, it is necessary to displace the light irradiation position (i.e., the drawing position) of each drawing head 41 on the substrate 9 in accordance with the deformation. For example, when the substrate 9 is enlarged in the X direction from the designed state, the drawing positions of the three drawing heads 41 on the (+X) side of the six drawing heads 41 need to be displaced in the (+X) direction, and the drawing positions of the three drawing heads 41 on the (-X) side need to be displaced in the (-X) direction.

[0080] In the imaging device 1, the imaging position is displaced in accordance with the deformation of the substrate 9 by the optical axis displacement unit 520. Specifically, based on the deformation of the substrate 9 acquired in step S31, the amount of displacement required in the X and Y directions of the imaging position on the substrate 9 by each imaging head 41 (i.e., the amount of displacement required of the optical axis J1) is calculated. Then, the amount of rotation of each of the optical elements 521 and 522 required to achieve the amount of displacement of the optical axis J1 (i.e., the amount of displacement of the second optical element group 52) is calculated (step S32).

[0081] Based on the deformation of the substrate 9 acquired in step S31, the imaging control unit 804 drives the element rotation mechanisms 523 and 524 of the optical axis displacement unit 520 to rotate the optical elements 521 and 522 by the rotation amount calculated in step S32 (step S33). By displacing the second optical element group 52 in this manner, the optical axis J1 of the projection optical system 45 is displaced in accordance with the displacement of the imaging position caused by the deformation of the substrate 9. As a result, deviation of the imaging position due to the deformation of the substrate 9 is suppressed, and the imaging accuracy on the substrate 9 is improved.

[0082] If the deformation of the substrate 9 is uniform in the Y direction, the amount of displacement of the optical axis J1 in response to the deformation of the substrate 9 is also constant regardless of the position in the Y direction, and therefore the displacement of the optical axis J1 (step S33) is performed, for example, before the start of irradiation of the substrate 9 with light (i.e., before step S17) as shown in Fig. 8. On the other hand, if the deformation of the substrate 9 varies depending on the position in the Y direction, the amount of displacement of the optical axis J1 in response to the deformation of the substrate 9 also varies depending on the position in the Y direction, and therefore the displacement of the optical axis J1 (step S33) is performed continuously in parallel with the drawing of the pattern on the substrate 9 (step S17).

[0083] Note that the above steps S31 and S32 are performed, for example, in parallel with steps S15 and S16. Steps S31 and S32 may be performed before or after steps S15 and S16, as long as they are performed between steps S14 and S17.

[0084] In the imaging device 1, the displacement of the second optical element group 52 to offset the optical axis shift accompanying the adjustment of the projection magnification described above (step S13) does not necessarily have to be performed between steps S12 and S14, and may be performed in step S17 together with the displacement of the second optical element group 52 corresponding to the deformation of the substrate 9 described above. In this case, the amount of displacement of the second optical element group 52 corresponding to the deformation of the substrate 9 may be added to the correction table described above. Furthermore, the displacement of the second optical element group 52 in the calibration described above (step S24) may also be performed in step S17 together with the displacement of the second optical element group 52 corresponding to the deformation of the substrate 9 described above.

[0085] In the imaging device 1, as described above, if the substrate 9 is enlarged in the X direction compared to the design state, the width in the X direction of the area to be imaged by one imaging head 41 also increases. As a result, the width in the X direction of the area to be imaged by each imaging head 41 in one main scan also increases. Therefore, in addition to displacing the imaging position of each imaging head 41 in accordance with the enlargement of the substrate 9 (i.e., displacing the optical axis J1 of the projection optical system 45), it may be necessary to enlarge the width in the X direction of the irradiation area of ​​the imaging head 41 on the substrate 9 (hereinafter also referred to as the "imaged width"). When the imaged width of the imaging head 41 is enlarged, the first optical element group 51 is displaced and the projection magnification of the projection optical system 45 is adjusted, in substantially the same manner as in step S11. The same applies when reducing the imaged width of the imaging head 41.

[0086] When the projection magnification is adjusted in accordance with the expansion of the drawing width, the drawing control unit 804 also calculates, in substantially the same manner as in step S12, the displacement amount of the second optical element group 52 necessary to offset the optical axis shift that occurs with the displacement of the first optical element group 51. Then, the drawing control unit 804 displaces the second optical element group 52 by the total displacement amount that is the sum of the displacement amount (i.e., the displacement amount of the second optical element group 52 necessary to offset the optical axis shift that occurs when the projection magnification is adjusted in accordance with the expansion of the drawing width) and the displacement amount of the second optical element group 52 necessary to displace the drawing position in accordance with the expansion of the substrate 9. This makes it possible to perform drawing with high accuracy on the expanded substrate 9 without generating linear undrawn regions due to insufficient drawing width.

[0087] In the drawing device 1, for example, it is possible that the deformation of the substrate 9 acquired in step S31 is so large that the displacement of the optical axis J1 by the optical axis displacement unit 520 cannot follow the deformation of the substrate 9. In this case, the drawing control unit 804 corrects the drawing data used to draw the pattern, rather than the displacement of the optical axis J1 by the optical axis displacement unit 520, to offset the deviation of the drawing position due to the deformation of the substrate 9.

[0088] For example, if the deviation between the coordinates of the alignment mark in the captured image acquired in step S14 and the coordinates of the designed alignment mark is equal to or greater than a predetermined threshold value (e.g., 500 ppm), the writing control unit 804 determines that the deformation of the substrate 9 is equal to or greater than a predetermined upper deformation limit (FIG. 9: step S41), and corrects the writing data in accordance with the deformation of the substrate 9 (step S42). The correction of the writing data in step S42 may be performed by various known correction methods, such as those described in Japanese Patent Application Laid-Open Nos. 2010-204421 and 2012-79739.

[0089] On the other hand, if the deformation of the substrate 9 acquired in step S31 is less than the above-mentioned upper deformation limit, the amount of displacement of the optical axis J1 is found based on the deformation of the substrate 9, as described above, and the amount of rotation of each of the optical elements 521, 522 of the second optical element group 52 (i.e., the amount of displacement of the second optical element group 52) is found (step S32). Then, the optical elements 521, 522 are rotated by the amount of rotation found in step S32, whereby the optical axis J1 of the projection optical system 45 is displaced in accordance with the displacement of the drawing position due to the deformation of the substrate 9 (step S33).

[0090] In the imaging device 1, whether steps S31, S41 to S42 are performed or steps S31 to S33 are performed, deviation of the imaging position due to deformation of the substrate 9 is suppressed, and imaging accuracy on the substrate 9 is improved. Note that in the imaging device 1, for example, when the deformation of the substrate 9 is equal to or greater than the upper deformation limit, both the displacement of the optical axis J1 due to the displacement of the second optical element group 52 and the correction of the imaging data may be performed.

[0091] As described above, the drawing device 1, which draws a pattern by irradiating light onto the substrate 9, includes the stage 21, the drawing head 41, the stage moving mechanism 22, the drawing control unit 804, and the storage unit 801. The stage 21 holds the substrate 9. The drawing head 41 irradiates the substrate 9 with modulated light. The stage moving mechanism 22 moves the stage 21 relative to the drawing head 41 in a scanning direction parallel to the upper surface 91 of the substrate 9 (the Y direction in the above example). The drawing control unit 804 controls the drawing head 41.

[0092] The drawing head 41 includes a light modulation unit 44 and a projection optical system 45. The light modulation unit 44 modulates the light emitted from the light source unit 42. The projection optical system 45 guides the light modulated by the light modulation unit 44 to the substrate 9. The projection optical system 45 includes a first optical element group 51 for adjusting the magnification and a second optical element group 52 for adjusting the optical axis position. The first optical element group 51 adjusts the projection magnification of the projection optical system 45 by displacing along the optical axis J1. The second optical element group 52 displaces the optical axis J1 in a direction perpendicular to the optical axis J1 (in the above example, the horizontal direction).

[0093] The storage unit 801 stores correction information indicating the relationship between the displacement of the second optical element group 52 required to offset the optical axis shift and the projection magnification. The optical axis shift is the shift of the optical axis J1 from the reference optical axis that occurs when the first optical element group 51 is displaced during adjustment of the projection magnification. The imaging control unit 804 displaces the second optical element group 52 based on the projection magnification of the projection optical system 45 and the correction information, thereby offsetting the optical axis shift that occurs during adjustment of the projection magnification. As described above, this makes it possible to suppress the optical axis shift that occurs during adjustment of the projection magnification of the projection optical system 45, thereby improving imaging accuracy.

[0094] As described above, the second optical element group 52 preferably includes a first parallel plate and a second parallel plate. The first parallel plate (i.e., optical element 521) displaces the optical axis J1 in a first direction (X direction in the above example) perpendicular to the optical axis J1. The second parallel plate (i.e., optical element 522) displaces the optical axis J1 in a second direction (Y direction in the above example) perpendicular to the optical axis J1 and the first direction. This makes it possible to achieve displacement of the optical axis J1 of the projection optical system 45 with a simple structure.

[0095] As described above, it is preferable that the drawing device 1 further includes the imaging unit 3 and the deformation acquisition unit 805. The imaging unit 3 captures an image of a mark (an alignment mark in the above example) on the substrate 9. The deformation acquisition unit 805 acquires the deformation of the substrate 9 based on the image captured by the imaging unit 3 (i.e., the captured image). The drawing control unit 804 displaces the second optical element group 52 based on the deformation of the substrate 9 acquired by the deformation acquisition unit 805, thereby displacing the optical axis J1 in accordance with the displacement of the drawing position according to the deformation of the substrate 9. This makes it possible to perform suitable drawing that corresponds to the deformation of the substrate 9, even if the substrate 9 is deformed.

[0096] As described above, it is preferable that the imaging control unit 804 displaces the optical axis J1 by displacing the second optical element group 52 based on the projection magnification and correction information of the projection optical system 45, even when adjusting the projection magnification required by displacing the optical axis J1 in accordance with the deformation of the substrate 9. This makes it possible to suppress optical axis misalignment that accompanies the adjustment of the projection magnification, even when adjustment of the projection magnification is required to accommodate the deformation of the substrate 9, thereby enabling suitable imaging that corresponds to the deformation of the substrate 9.

[0097] As described above, it is preferable that the drawing control unit 804 corrects the drawing data used for drawing a pattern when the deformation of the substrate 9 acquired by the deformation acquisition unit 805 is equal to or greater than a predetermined upper deformation limit. This makes it possible to draw a pattern on the substrate 9 with high accuracy even when a large deformation occurs in the substrate 9 that cannot be addressed by the displacement of the optical axis J1 caused by the displacement of the second optical element group 52 alone.

[0098] As described above, the imaging device 1 preferably includes another imaging head 41 having the same structure as the imaging head 41 and an irradiation position measurement unit 260. The irradiation position measurement unit 260 measures the irradiation positions of light from each of the imaging head 41 and the other imaging head 41. The storage unit 801 further stores correction information related to the other imaging head 41. The imaging control unit 804 also offsets optical axis misalignment that occurs when adjusting the projection magnification of the other imaging head 41. Based on the measurement results from the irradiation position measurement unit 260, the imaging control unit 804 calculates an irradiation position interval, which is the distance between the irradiation position of the imaging head 41 and the irradiation position of the other imaging head 41. The imaging control unit 804 displaces the second optical element group 52 of the imaging head 41 and the optical axis J1 of the imaging head 41 so that the irradiation position interval becomes a desired interval. This allows the irradiation positions of the multiple imaging heads 41 to be suitably spaced at a desired interval.

[0099] The above-described drawing method includes a step (step S10) of pre-storing correction information indicating the relationship between the projection magnification and the displacement of the second optical element group 52 required to offset the optical axis shift, which is the deviation of the optical axis J1 from the reference optical axis that occurs with the displacement of the first optical element group 51 when adjusting the projection magnification, and a step (step S13) of displacing the second optical element group 52 based on the projection magnification of the projection optical system 45 and the correction information to offset the optical axis shift that occurs when adjusting the projection magnification. This makes it possible to suppress the optical axis shift that occurs with the adjustment of the projection magnification of the projection optical system 45, and improve drawing accuracy, as described above.

[0100] Next, a method for generating the above-mentioned correction information will be described. FIG. 10 is a side view showing the configuration of a correction information generating device 7 used to generate correction information. FIG. 10 also shows a part of the drawing head 41 for which correction information is generated by the correction information generating device 7. The correction information generating device 7 includes a correction jig 71 and a correction information generating unit 72. In the example shown in FIG. 10, the correction jig 71 is attached to the light modulation unit 44 and the projection optical system 45 fixed to the frame 47. The correction jig 71 does not constitute the drawing head 41 of the drawing apparatus 1, and is detached from the drawing head 41 before the drawing head 41 is attached to the support unit 40.

[0101] The correction jig 71 includes a beam sampler 73, a condenser lens 74, and a light-receiving element 75. The beam sampler 73 is inserted on the optical axis J1 of the projection optical system 45 and extracts a portion of the light passing through the projection optical system 45. In the example shown in FIG. 10 , the beam sampler 73 is disposed between the first optical element group 51 and the third optical element group 53, which is an objective lens. No other optical elements exist between the beam sampler 73 and the third optical element group 53 in the direction along the optical axis J1. In other words, the beam sampler 73 of the correction jig 71 is disposed immediately before the third optical element group 53, which is an objective lens. Note that the insertion position of the beam sampler 73 is not necessarily limited to the position shown in FIG. 10 , and may be variously changed, as long as it is disposed on the optical axis J1 of the projection optical system 45.

[0102] The beam sampler 73 extracts the light guided by the projection optical system 45 in a direction approximately perpendicular to the optical axis J1 and guides it to a condenser lens 74. The condenser lens 74 converges the light guided by the beam sampler 73 and guides it to a light receiving element 75. The light receiving element 75 receives the light guided by the condenser lens 74. The light receiving element 75 is, for example, a CCD or CMOS. The light receiving position on the light receiving element 75 is sent to a correction information generation unit 72. The correction information generation unit 72 is a function realized by a normal computer having approximately the same configuration as the computer 800 shown in FIG. 4.

[0103] 11 and 12 are diagrams showing the flow of generating correction information. When generating correction information, first, the projection optical system 45 is placed on a table (not shown). In the example shown in Fig. 10, the projection optical system 45 is placed on the table while being fixed to a frame 47 together with the light modulation unit 44. For convenience, Fig. 10 depicts the optical axis J1 of the projection optical system 45 as being approximately parallel to the Z direction, but the placement orientation of the projection optical system 45 may be changed in various ways.

[0104] Next, the beam sampler 73 of the correction jig 71 is inserted onto the optical axis J1 of the projection optical system 45. Furthermore, light emitted from a separately prepared light source (e.g., an LED) is guided to the second optical element group 52 of the projection optical system 45, and passes through the second optical element group 52, the first optical element group 51, and the third optical element group 53 in that order. Then, a portion of the light guided by the projection optical system 45 is extracted by the beam sampler 73 and received by the light receiving element 75 (step S51). The light receiving position on the light receiving element 75 is sent to the correction information generation unit 72.

[0105] The correction information generating unit 72 generates correction information for the projection optical system 45 based on the light receiving position on the light receiving element 75 (that is, the light receiving position on the correction jig 71) (step S52).

[0106] Specifically, in step S52, first, the optical elements 511, 512 of the first optical element group 51 are displaced along the optical axis J1 to variously change the projection magnification of the projection optical system 45, and the light-receiving position on the light-receiving element 75 is acquired. As a result, the optical axis deviation during adjustment of the projection magnification (i.e., the deviation of the optical axis J1 from the reference optical axis that occurs as the first optical element group 51 is displaced) is acquired corresponding to each of the multiple projection magnifications (step S521).

[0107] Next, the optical elements 521 and 522 of the second optical element group 52 are each rotated, and the rotation amount of the optical elements 521 and 522 that offsets the optical axis shift is determined for each of a plurality of projection magnifications. Then, the rotation amount of the optical elements 521 and 522 (i.e., the displacement of the second optical element group 52) is associated with the projection magnification, thereby generating the above-mentioned correction information that indicates the relationship between the projection magnification and the displacement of the second optical element group 52 that is necessary to offset the optical axis shift corresponding to the projection magnification (step S522). Note that in step S522, the rotation amount of the optical elements 521 and 522 corresponding to each projection magnification may be determined by optical simulation or the like.

[0108] As described above, the correction information generating device 7, which generates correction information for the projection optical system 45 that guides light to an object and projects an image, includes the correction jig 71 and the correction information generating unit 72. The correction jig 71 is inserted onto the optical axis J1 of the projection optical system 45. The correction jig 71 extracts and receives a portion of the light guided by the projection optical system 45. The correction information generating unit 72 generates correction information for the projection optical system 45 based on the light receiving position on the correction jig 71. The projection optical system 45 includes a first optical element group 51 for adjusting the magnification and a second optical element group 52 for adjusting the optical axis position. The first optical element group 51 adjusts the projection magnification of the projection optical system 45 by displacing along the optical axis J1. The second optical element group 52 displaces the optical axis J1 in a direction perpendicular to the optical axis J1 by displacing.

[0109] The correction information generation unit 72 acquires the optical axis misalignment based on the light receiving position on the correction jig 71. The optical axis misalignment is a deviation of the optical axis J1 from the reference optical axis that occurs with the displacement of the first optical element group 51 when adjusting the projection magnification. The correction information generation unit 72 generates correction information that indicates the relationship between the projection magnification and the displacement of the second optical element group 52 that is required to offset the optical axis misalignment, based on the relationship between the optical axis misalignment and the projection magnification. This makes it possible to obtain correction information that is used to offset the optical axis misalignment that occurs when adjusting the projection magnification.

[0110] As described above, the beam sampler 73 of the correction jig 71 is preferably disposed immediately before the third optical element group 53, which is the objective lens. In other words, the beam sampler 73 is preferably disposed at a position between the first optical element group 51 and the third optical element group 53, closest to the third optical element group 53 in the direction along the optical axis J1. In this way, by using the beam sampler 73 to extract the parallel light beam immediately before it enters the third optical element group 53, which is the objective lens, the structure of the correction jig 71 can be simplified.

[0111] The above-described correction information generating method includes a step of inserting a correction jig 71 onto the optical axis J1 of the projection optical system 45 and receiving a portion of the light guided by the projection optical system 45 (step S51), and a step of generating correction information for the projection optical system 45 based on the light-receiving position on the correction jig 71 (step S52). Step S52 includes a step of acquiring, based on the light-receiving position on the correction jig 71, an optical axis shift, which is a deviation of the optical axis J1 from a reference optical axis that occurs with the displacement of the first optical element group 51 when adjusting the projection magnification (step S521), and a step of generating, based on the relationship between the optical axis shift and the projection magnification, correction information that indicates the relationship between the displacement of the second optical element group 52 required to offset the optical axis shift and the projection magnification (step S522). As a result, as described above, correction information used to offset the optical axis shift associated with the adjustment of the projection magnification can be obtained.

[0112] The above-described drawing device 1, correction information generating device 7, drawing method, and correction information generating method can be modified in various ways.

[0113] For example, in the drawing device 1, the displacement of the optical axis J1 based on the measurement results of the irradiation position measurement unit 260 does not necessarily have to be achieved by displacing the second optical element group 52, but may be achieved, for example, by adjusting the mounting position of the drawing head 41 relative to the support unit 40, etc.

[0114] The optical elements 521 and 522 of the second optical element group 52 do not necessarily have to be parallel plates, and may be optical elements other than parallel plates. For example, the second optical element group 52 may be composed of a plurality of wedge prisms.

[0115] In the correction information generating device 7, the structure of the correction jig 71 is not limited to the above example, and may be modified in various ways.

[0116] The above-described correction information may be generated by a device other than the correction information generating device 7. Furthermore, the correction information may be generated by a method other than the above-described correction information generating method.

[0117] The correction information generated by the correction information generating device 7 may be used to offset the optical axis shift that occurs when adjusting the projection magnification of the projection optical system 45 in a device other than the drawing device 1 that draws a pattern by irradiating light onto a substrate 9.

[0118] The configurations in the above-described embodiment and each modification may be combined as appropriate as long as they are not mutually contradictory. [Explanation of symbols]

[0119] 1 Drawing device 3. Imaging unit 7 Correction information generation device 9 Substrate 21 Stages 22 Stage movement mechanism 41 Drawing head 44 Optical modulation section 45 Projection optical system 51 First optical element group 52 Second optical element group 71 Correction jig 72 Correction information generation section 91 (board) top surface 260 Irradiation position measurement section 521,522 Optical elements 801 Storage section 802 Irradiation position acquisition unit 803 Position detection unit 804 Drawing control unit 805 Deformation Acquisition Unit J1 optical axis S10~S17, S21~S24, S31~S33, S41~S42, S51~S52, S521~S522 steps

Claims

1. A drawing apparatus that draws a pattern by irradiating a substrate with light, a stage for holding the substrate; a drawing head that irradiates the substrate with modulated light; a stage moving mechanism that moves the stage relative to the drawing head in a scanning direction parallel to an upper surface of the substrate; a drawing control unit that controls the drawing head; A memory unit; Equipped with The drawing head includes: a light modulation unit that modulates light emitted from the light source unit; a projection optical system that guides the light modulated by the light modulation unit to a substrate; Equipped with The projection optical system includes: a first optical element group for adjusting the magnification, which adjusts the projection magnification of the projection optical system by being displaced along the optical axis; a second optical element group for adjusting the optical axis position, the second optical element group being displaced to displace the optical axis in a direction perpendicular to the optical axis; Equipped with the storage unit stores correction information indicating a relationship between the projection magnification and a displacement of the second optical element group required to offset an optical axis shift, which is a shift of the optical axis from a reference optical axis that occurs with a displacement of the first optical element group when adjusting the projection magnification; The imaging control unit displaces the second optical element group based on the projection magnification of the projection optical system and the correction information, thereby offsetting the optical axis deviation when adjusting the projection magnification.

2. 2. The drawing device according to claim 1, The second optical element group is a first parallel plate that displaces the optical axis in a first direction perpendicular to the optical axis; a second parallel plate that displaces the optical axis in a second direction perpendicular to the optical axis and the first direction; Drawing device including:

3. 3. The drawing device according to claim 1, an imaging unit that images the mark on the substrate; a deformation acquisition unit that acquires deformation of the substrate based on the image captured by the imaging unit; Furthermore, The drawing control unit displaces the second optical element group based on the deformation of the substrate acquired by the deformation acquisition unit, thereby displacing the optical axis in response to the displacement of the drawing position due to the deformation of the substrate.

4. 4. The drawing device according to claim 3, The drawing control unit displaces the optical axis by displacing the second optical element group based on the projection magnification of the projection optical system and the correction information, even when adjusting the projection magnification, which becomes necessary by displacing the optical axis in accordance with deformation of the substrate.

5. 4. The drawing device according to claim 3, The drawing control unit corrects drawing data used for drawing a pattern when the deformation of the substrate acquired by the deformation acquisition unit is equal to or greater than a predetermined upper deformation limit.

6. 3. The drawing device according to claim 1, another drawing head having the same structure as the drawing head; an irradiation position measuring unit that measures irradiation positions of light from the imaging head and the other imaging head; Furthermore, the storage unit further stores the correction information related to the other drawing head; the imaging control unit also offsets the optical axis misalignment when adjusting the projection magnification of the other imaging head, The drawing control unit calculates an irradiation position interval, which is the distance between the irradiation position of the drawing head and the irradiation position of the other drawing head, based on the measurement results of the irradiation position measurement unit, and displaces the second optical element group of the drawing head to displace the optical axis of the drawing head so that the irradiation position interval becomes a desired interval.

7. 1. A correction information generating device that generates correction information for a projection optical system that guides light to an object and projects an image, comprising: a correction jig that is inserted onto the optical axis of the projection optical system and receives a portion of the light guided by the projection optical system; a correction information generating unit that generates correction information for the projection optical system based on the light receiving position on the correction jig; Equipped with The projection optical system includes: a first optical element group for adjusting a magnification, which is displaced along the optical axis to adjust a projection magnification of the projection optical system; a second optical element group for adjusting the optical axis position, the second optical element group being displaced to displace the optical axis in a direction perpendicular to the optical axis; Equipped with The correction information generation unit acquires, based on the light receiving position on the correction jig, an optical axis shift, which is the deviation of the optical axis from a reference optical axis that occurs due to the displacement of the first optical element group when adjusting the projection magnification, and generates, based on the relationship between the optical axis shift and the projection magnification, the correction information generation device that indicates the relationship between the displacement of the second optical element group required to offset the optical axis shift and the projection magnification.

8. A pattern drawing method for drawing a pattern by irradiating a substrate with modulated light from a drawing head, comprising: The drawing head is a light modulation unit that modulates light emitted from the light source unit; a projection optical system that guides the light modulated by the light modulation unit to a substrate; Equipped with The projection optical system includes: a first optical element group for adjusting the magnification, which adjusts the projection magnification of the projection optical system by being displaced along the optical axis; a second optical element group for adjusting the optical axis position, the second optical element group being displaced to displace the optical axis in a direction perpendicular to the optical axis; Equipped with The drawing method includes: a) storing in advance correction information indicating a relationship between the projection magnification and a displacement of the second optical element group required to offset an optical axis shift, which is a shift of the optical axis from a reference optical axis that occurs with a displacement of the first optical element group when adjusting the projection magnification; b) displacing the second optical element group based on the projection magnification of the projection optical system and the correction information to offset the optical axis deviation that occurs when adjusting the projection magnification; A drawing method comprising:

9. 1. A correction information generation method for generating correction information for a projection optical system that guides light to an object and projects an image, comprising: a) inserting a correction jig onto the optical axis of a projection optical system, and extracting and receiving a portion of light guided by the projection optical system; b) generating correction information for the projection optical system based on the light receiving position on the correction jig; Equipped with The projection optical system includes: a first optical element group for adjusting a magnification, which is displaced along the optical axis to adjust a projection magnification of the projection optical system; a second optical element group for adjusting the optical axis position, the second optical element group being displaced to displace the optical axis in a direction perpendicular to the optical axis; Equipped with The step b) comprises: c) acquiring an optical axis deviation, which is a deviation of the optical axis from a reference optical axis that occurs due to a displacement of the first optical element group when adjusting the projection magnification, based on a light receiving position on the correction jig; d) generating the correction information indicating the relationship between the projection magnification and the displacement of the second optical element group required to offset the optical axis shift, based on the relationship between the optical axis shift and the projection magnification; A correction information generating method comprising:

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