Optical device and drawing device

Abstract

To cool a digital micro mirror device while suppressing condensation.SOLUTION: A light modulation part 44 of an optical device comprises a digital micro mirror device (DMD) 6 and a cooling part 7 which cools DMD 6. The cooling part 7 comprises a first ejection channel 764 and a first supply channel 765. The first ejection channel 764 ejects gas from the first ejection port 763, and cools DMD 6 by forming an air flow along a principal surface 631 on a (-Z) side of a DMD cover part 63. The first supply channel 765 connects a gas supply source and the first ejection channel 764, and leads compressed air sent from the gas supply source to the first ejection channel 764. A channel cross-section area of the first supply channel 765 is smaller than a channel cross-section area of the first ejection channel 764. This makes it possible to cool DMD 6 while suppressing condensation.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an optical device that irradiates an object with modulated light, and a drawing apparatus that includes the optical device and irradiates a substrate with light to 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 directly draws a pattern by irradiating a photosensitive material formed on the board with modulated light and scanning the irradiated area of ​​the light.

[0003] In such a drawing device, a digital micromirror device (DMD) is used as one of the optical modulators that modulates light in the drawing head that emits light toward the substrate. When the drawing device is in operation, the temperature of the DMD rises due to heat generated by the operation of the DMD and heat from the light irradiated onto the mirror part of the DMD. If the temperature of the DMD falls outside the range of the specified operating temperature conditions, the quality of the DMD may deteriorate early, so the drawing device may cool the DMD.

[0004] For example, the device of Patent Document 1 is provided with an air-cooling assembly that blows air toward the underside of the DMD chip to cool it. Specifically, as shown in Fig. 3 and Fig. 8, an air flow path is provided inside a mount 9 that supports the DMD assembly 5 from below, and air is blown from the nozzle of the air flow path located on the right side in Fig. 8 toward the underside of the DMD chip placed in the through hole of the mount 9. A guide plate 11 is provided near the nozzle of the air flow path, and the flow path cross-sectional area of ​​the air flow path becomes smaller as it approaches the nozzle. Therefore, the air flowing through the air flow path is sprayed from the nozzle while being accelerated, and is blown onto the underside of the DMD chip. The air blown onto the underside of the DMD chip is discharged from the air flow path located on the left side in Fig. 8. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] China Utility Model Publication No. 216671613 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the device of Patent Document 1, moisture in the air may condense due to adiabatic expansion of the air ejected from the ejection port, and water droplets may adhere to the cover glass surface of the DMD chip. In the above-mentioned drawing device, if water droplets adhere to the cover glass surface of the DMD chip and stain it, the amount of light irradiated to the substrate decreases.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has an object to cool a digital micromirror device while suppressing condensation. [Means for solving the problem]

[0008] A first aspect of the present invention is an optical device for irradiating an object with modulated light, the optical device comprising: an illumination optical system into which light emitted from a light source is incident; an optical modulation section for modulating the light guided by the illumination optical system; and a projection optical system for guiding the light modulated by the optical modulation section to the object. The optical modulation section comprises a digital micromirror device and a cooling section for cooling the digital micromirror device. The digital micromirror device comprises a DMD base section, a DMD mirror section including a plurality of movable micromirrors arranged in a matrix on one side in the thickness direction of the DMD base section, and a DMD cover section for covering the DMD mirror section from the one side in the thickness direction. The cooling section comprises an ejection flow path for ejecting gas from an ejection port to form an airflow along the main surface on the one side in the thickness direction of the DMD cover section to cool the digital micromirror device, and a supply flow path for connecting a gas supply source and the ejection flow path to guide the compressed gas sent from the gas supply source to the ejection flow path and having a flow path cross-sectional area smaller than that of the ejection flow path.

[0009] A second aspect of the present invention is the optical device of the first aspect, wherein the optical modulation section further includes a device holding section for holding the digital micromirror device. The device holding section includes a cover accommodating recess that opens to the one side in the thickness direction and has the DMD cover section disposed therein. The ejection flow path includes at least a portion of a through flow path that penetrates the device holding section from the inner peripheral surface of the cover accommodating recess. A connection portion between the supply flow path and the ejection flow path is located at an end of the through flow path opposite the cover accommodating recess, or midway through the through flow path.

[0010] A third aspect of the present invention is the optical device of the first aspect (which may be either the first or second aspect), wherein the size of the nozzle in a direction perpendicular to the thickness direction is greater than the size of the nozzle in the thickness direction.

[0011] A fourth aspect of the present invention is the optical device of the first aspect (which may be any one of the first to third aspects), wherein the cross-sectional area of ​​the ejection flow path is 2.25 times or more the cross-sectional area of ​​the supply flow path.

[0012] Aspect 5 of the present invention is an optical device of aspect 1 (which may be any one of aspects 1 to 4), wherein the flow direction of the air flow formed by the cooling section is parallel to the main surface on one side of the thickness direction of the DMD cover section.

[0013] A sixth aspect of the present invention is the optical device of the first aspect (which may be any one of the first to fifth aspects), in which the direction of incidence of light on the digital micromirror device is inclined in a lateral direction perpendicular to the thickness direction with respect to the thickness direction, and the flow direction of the airflow formed by the cooling unit is parallel to the lateral direction.

[0014] A seventh aspect of the present invention is the optical device of the first aspect (which may be any one of the first to sixth aspects), in which the cooling section further includes another ejection flow path for ejecting gas from another ejection port to form another airflow along the main surface of the one side in the thickness direction of the DMD cover section to cool the digital micromirror device, and another supply flow path for connecting a gas supply source and the other ejection flow path to guide compressed gas discharged from the gas supply source to the other ejection flow path and having a smaller flow path cross-sectional area than the other ejection flow path. The airflow caused by the gas ejected from the ejection port flows from one side to the other side in the horizontal direction perpendicular to the thickness direction. The other airflow caused by the gas ejected from the other ejection port flows from the other side to the one side in the horizontal direction.

[0015] Aspect 8 of the present invention is the optical device of aspect 7, wherein the positions of the jet outlet and the other jet outlet in the direction perpendicular to the thickness direction and the lateral direction are different from each other.

[0016] A ninth aspect of the present invention is a drawing apparatus that draws a pattern by irradiating light onto a substrate, and includes a stage that holds the substrate, an optical device of any one of aspects 1 to 8 that irradiates modulated light onto the substrate, and a scanning mechanism that moves the stage relative to the optical device in a scanning direction parallel to a main surface of the substrate. Effect of the Invention

[0017] According to the present invention, it is possible to cool the digital micromirror device while suppressing condensation. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a drawing device according to an embodiment; [Diagram 2] FIG. [Diagram 3] FIG. 4 is a side view of the optical modulation unit. [Figure 4] FIG. 2 is a perspective view of a light modulation unit. [Diagram 5]FIG. 4 is a bottom view of the optical modulation unit. [Figure 6] FIG. 4 is a perspective view showing a first ejection port. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 1 is a perspective view showing a drawing apparatus 1 according to one embodiment of the present invention. The drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating a photosensitive material on a substrate 9 with spatially modulated light in a substantially beam shape and scanning the irradiated area of ​​the light on the substrate 9. In FIG. 1, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in FIG. 1, the X direction and the Y direction are horizontal directions perpendicular to each other, and the Z direction is a vertical direction (i.e., an up-down direction). The same applies to other figures.

[0020] The substrate 9 is, for example, a printed circuit board having a substantially rectangular flat plate shape. On the (+Z) main surface (hereinafter also referred to as "upper surface 91") of the substrate 9, a resist film formed of a photosensitive material is provided on a copper layer. In the drawing device 1, a circuit pattern is drawn (i.e., formed) on the resist film of the substrate 9. The type, shape, etc. of the substrate 9 may be changed in various ways.

[0021] The imaging apparatus 1 is placed in a clean room (not shown) The temperature in the clean room is, for example, 20° C. to 23° C., and the relative humidity in the clean room is, for example, 33% to 48%.

[0022] The drawing apparatus 1 includes a stage 21, a stage moving mechanism 22, an alignment unit 3, and a drawing unit 4. The stage 21 is a substantially rectangular flat member disposed below the alignment unit 3 and the drawing unit 4 (i.e., on the (-Z) side). The stage 21 includes a substrate holding unit 25 that holds the substrate 9 in a horizontal state from below. The substrate holding unit 25 is, for example, a vacuum chuck that adsorbs and holds the lower surface of the substrate 9. The substrate holding unit 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 holding unit 25 is substantially perpendicular to the Z direction and substantially parallel to the X direction and the Y direction.

[0023] The stage moving mechanism 22 is a moving mechanism that moves the stage 21 relatively to the alignment unit 3 and the drawing unit 4 in a horizontal direction (i.e., a direction approximately parallel to the upper surface 91 of the substrate 9). The stage moving mechanism 22 is attached on the upper surface of the base 11 and is supported from below by the base 11. The stage moving mechanism 22 includes a first moving mechanism 23 and a second moving mechanism 24. The second moving mechanism 24 supports the stage 21 from below and linearly moves the stage 21 in the X direction along the guide rail. The first moving mechanism 23 supports the second moving mechanism 24 from below and linearly moves the stage 21 together with the second moving mechanism 24 in the Y direction along the guide rail. The driving sources of the first moving mechanism 23 and the second moving mechanism 24 are, for example, linear servo motors or motors attached to ball screws. The structures of the first moving mechanism 23 and the second moving mechanism 24 may be variously modified.

[0024] The drawing apparatus 1 may be provided with a stage rotation mechanism that rotates the stage 21 about a rotation axis extending in the Z direction. The drawing apparatus 1 may also be provided with a stage lifting mechanism that moves the stage 21 in the Z direction. For example, a servo motor can be used as the stage rotation mechanism. For example, a linear servo motor can be used as the stage lifting mechanism. The structures of the stage rotation mechanism and the stage lifting mechanism may be modified in various ways.

[0025] The alignment unit 3 includes a plurality of alignment cameras 31. In the example shown in FIG. 1, two alignment cameras 31 are arranged in the X direction, but only the alignment camera 31 on the (+X) side is shown. Each alignment camera 31 is supported above the stage 21 and the stage movement mechanism 22 by a support 27 that is provided across the stage 21 and the stage movement mechanism 22. The support 27 is, for example, a single metal member provided at one position in the Y direction. In the example shown in FIG. 1, the support 27 is a gate-shaped member (a so-called gantry) that is provided across the stage 21 and the stage movement mechanism 22, and is erected on the upper surface of the base 11.

[0026] 1, the two alignment cameras 31 are attached to the (+Y) side surface of the support unit 27. Of the two alignment cameras 31, for example, one alignment camera 31 is fixed to the support unit 27, and the other alignment camera 31 is movable in the X direction on the support unit 27. This makes it possible to change the distance in the X direction between the two alignment cameras 31. Note that the number of alignment cameras 31 in the alignment unit 3 may be one, or three or more.

[0027] Each alignment camera 31 captures an image of an alignment mark (not shown) provided in advance on the upper surface 91 of the substrate 9. In the drawing device 1, alignment of the substrate 9 (i.e., correction of the relative position of the substrate 9 with respect to the drawing head 41) is performed based on the image of the alignment mark acquired by the alignment camera 31.

[0028] The drawing unit 4 includes a plurality of drawing heads 41 (six in the example shown in FIG. 1) arranged in the X direction. The plurality of drawing heads 41 have approximately the same structure. Each drawing head 41 includes an optical modulator that irradiates modulated (i.e., spatially modulated) light downward. Each drawing head 41 is supported above the stage 21 and the stage moving mechanism 22 by the above-mentioned support unit 27. In the example shown in FIG. 1, the six drawing heads 41 are attached to the (-Y) side surface of the support unit 27. Note that the above-mentioned alignment camera 31 may be supported by a support unit different from the support unit 27 to which the drawing heads 41 are attached.

[0029] 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. The multiple drawing heads 41 do not necessarily need to be arranged in a straight line, and may be arranged, for example, in a staggered manner. When the drawing heads 41 are arranged in a staggered manner, for example, the multiple drawing heads 41 are arranged substantially parallel to the X direction at a first position in the Y direction, and at a second position adjacent to the (-Y) side of the first position, a drawing head 41 is arranged between each of the multiple drawing heads 41 in the X direction. Moreover, the number of drawing heads 41 in the drawing unit 4 may be one or more than two.

[0030] In the drawing device 1, pattern drawing on the substrate 9 is performed by a so-called multi-pass method. Specifically, while modulated light from the multiple drawing heads 41 of the drawing unit 4 is irradiated onto the upper surface 91 of the substrate 9, the first moving mechanism 23 of the stage moving mechanism 22 moves the substrate 9 in the Y direction to pass under the drawing heads 41. As a result, the irradiation area of ​​the light from the multiple drawing heads 41 is scanned in the Y direction on the substrate 9, and drawing on the substrate 9 is performed. Next, the second moving mechanism 24 moves the substrate 9 stepwise by a predetermined distance in the X direction. Then, the first moving mechanism 23 moves the substrate 9 in the Y direction, and the drawing heads 41 irradiate the substrate 9 with light in parallel with the movement again, thereby performing drawing on the substrate 9. In the drawing device 1, the irradiation of light on the substrate 9 moving in the Y direction and the step movement of the substrate 9 in the X direction are alternately performed, thereby performing drawing on the substrate 9.

[0031] In the following description, the Y direction is also referred to as the "main scanning direction" or "scanning direction", and the X direction is also referred to as the "sub-scanning direction". The main scanning direction and the sub-scanning direction are directions that are approximately parallel to the upper surface 91 of the substrate 9. In the stage movement mechanism 22, the first movement mechanism 23 is a main scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the main scanning direction. The second movement mechanism 24 is a sub-scanning mechanism that moves the stage 21 relatively to the drawing head 41 in the sub-scanning direction.

[0032] In the drawing apparatus 1, drawing on the substrate 9 may be performed by a single pass method (also called a one-pass method) in which drawing of a pattern on the substrate 9 is completed by moving the substrate 9 relatively to the drawing head 41 only once in the Y direction. In this case, sub-scanning of the substrate 9 by the second moving mechanism 24 (i.e., step movement in the X direction) is not performed when drawing the pattern. In other words, the stage moving mechanism 22 is a scanning mechanism that moves the stage 21 at least in the scanning direction relative to the drawing head 41.

[0033] 2 is an enlarged side view of one drawing head 41 viewed from the (+X) side. The drawing head 41 includes a light source unit 42, an illumination optical system 43, a light modulation unit 44, a projection optical system 45, and a drawing head cover 46. The light source unit 42, the illumination optical system 43, the light modulation unit 44, and the projection optical system 45 are housed inside the drawing head cover 46. In FIG. 2, in order to facilitate understanding of the drawing, the drawing head cover 46 is shown in cross section, and the internal structure of the drawing head cover 46 is shown by solid lines. In addition, FIG. 2 also shows the support unit 27.

[0034] In the example shown in FIG. 2, the drawing head cover 46 is a substantially L-shaped member in a side view. The light source unit 42 is disposed inside the drawing head cover 46 at the (+Y) end of the upper part of the drawing head 41. The illumination optical system 43 is disposed inside the drawing head cover 46 at the (-Y) side of the light source unit 42 at the upper part of the drawing head 41. The illumination optical system 43 extends substantially parallel to the Y direction. The light modulation unit 44 is disposed inside the drawing head cover 46 at the (-Y) end of the upper part of the drawing head 41. The light modulation unit 44 is located on the (-Y) side of the illumination optical system 43.

[0035] The projection optical system 45 is disposed inside the drawing head cover 46 at the end on the (-Y) side of the drawing head 41, on the (-Z) side (i.e., below) of the light modulation unit 44. The projection optical system 45 extends approximately parallel to the Z direction. In the example shown in Fig. 2, the lower end of the drawing head cover 46 is open, and the lower end of the projection optical system 45 protrudes downward from the lower end opening of the drawing head cover 46. A focus sensor or the like used for focus adjustment of the drawing head 41 may be provided near the lower end of the projection optical system 45.

[0036] The shape of the drawing head cover 46 may be changed in various ways, and for example, the drawing head cover 46 may be a member extending approximately parallel to the Z direction. In this case, the illumination optical system 43 and the light source unit 42 are disposed on the (+Z) side of the light modulation unit 44, for example.

[0037] The light emitted from the light source unit 42 enters the illumination optical system 43 along a predetermined optical axis J1 of the drawing head 41, and is guided to the light modulation unit 44 via the illumination optical system 43 and mirrors 471, 472, etc. In FIG. 2, the optical axis J1 is depicted by a dashed line. The light modulation unit 44 guides the light from the light source unit 42 to the projection optical system 45 while modulating it. The light modulated by the light modulation unit 44 is guided by the projection optical system 45 to the upper surface 91 (see FIG. 1) of the substrate 9, which is an object located below the drawing head 41 (i.e., in the (-Z) direction).

[0038] The light source unit 42 includes a light source 421 such as an LED (Light Emitting Diode) or an LD (Laser Diode). The illumination optical system 43 includes optical elements such as a plurality of lenses arranged substantially parallel to the Y direction. The light modulation unit 44 includes a digital micromirror device 6 (hereinafter also referred to as "DMD6") which is a spatial light modulator. The projection optical system 45 includes optical elements such as a plurality of lenses arranged substantially parallel to the Z direction.

[0039] 2, one light source 421 is depicted in the light source section 42, but the number of light sources 421 provided in the light source section 42 may be multiple. For example, multiple light sources 421 emitting light of different wavelengths may be provided in the light source section 42. In this case, when drawing a pattern on the substrate 9, one or more light sources 421 are selected and used from the multiple light sources 421 according to the type of photosensitive material on the substrate 9, etc. The light source 421 provided in the light source section 42 is not limited to an LED and an LD, and various types of light sources can be used.

[0040] In the drawing apparatus 1, the above-mentioned illumination optical system 43, light modulation unit 44, and projection optical system 45 constitute an optical device 10 that irradiates an object (i.e., substrate 9) with modulated light. Note that the optical device 10 may also include other components such as a light source unit 42 and a drawing head cover 46.

[0041] FIG. 3 is an enlarged side view of the light modulation section 44. FIG. 4 is a perspective view of the light modulation section 44 seen obliquely from below. FIG. 5 is a bottom view of a portion of the light modulation section 44 near the DMD 6 seen from the (-Z) side. The light modulation section 44 includes the above-mentioned DMD 6, a support substrate 60, a cooling section 7, and a housing member 8. The housing member 8 is a cover member provided on the (+Z) side of the support substrate 60 and covers the cooling section 7 and the like. To facilitate understanding of the figures, the housing member 8 is shown in cross section in FIG. 3, and is shown by a dashed line in FIG. 4.

[0042] The support substrate 60 is a substantially flat plate-like member extending substantially perpendicularly to the Z direction, and supports the DMD 6 and the cooling unit 7. The shape of the support substrate 60 in a plan view (i.e., the shape when viewed parallel to the Z direction from the (+Z) side) is, for example, substantially rectangular. The support substrate 60 is provided with a through hole 601 penetrating the support substrate 60 in the Z direction. The shape of the through hole 601 in a plan view is, for example, substantially circular. In the example shown in FIGS. 3 to 5, the portion of the support substrate 60 surrounding the through hole 601 has a greater thickness in the Z direction than other portions of the support substrate 60 (for example, the end on the (+Y) side and the end on the (-Y) side, etc.).

[0043] The DMD 6 is a member having a substantially rectangular shape in a plan view. The DMD 6 is attached from above to a through-hole 601 provided in the support substrate 60. In other words, the DMD 6 is attached to the upper surface (i.e., the main surface on the (+Z) side) of the support substrate 60 so as to overlap with the through-hole 601 in a plan view. In other words, the support substrate 60 is a device holder that holds the DMD 6.

[0044] The DMD 6 includes a DMD base section 61, a DMD mirror section 62, and a DMD cover section 63. The DMD base section 61 is a substantially flat plate-shaped member that extends substantially perpendicularly to the Z direction. That is, the Z direction is the thickness direction of the DMD base section 61 and also the thickness direction of the DMD 6. The shape of the DMD base section 61 in a plan view is, for example, substantially rectangular. The DMD base section 61 directly or indirectly contacts the upper surface of the support substrate 60 and is supported from below by the support substrate 60. The DMD base section 61 is provided with a receiving section that receives a drive signal input from outside the DMD 6, a drive section that drives the DMD mirror section 62 based on the drive signal, and the like.

[0045] The DMD mirror section 62 is provided on the main surface on the (-Z) side of the DMD base section 61. The shape of the DMD mirror section 62 in a plan view is, for example, approximately rectangular. The size of the DMD mirror section 62 in a plan view is smaller than the size of the DMD base section 61 in a plan view. The entire DMD mirror section 62 is covered by the DMD base section 61 from the (+Z) side.

[0046] The DMD mirror section 62 includes a plurality of movable micromirrors (not shown) arranged in a matrix. The plurality of micromirrors are driven independently of one another by the driving section provided in the DMD base section 61, and can be switched between an ON state and an OFF state. The plurality of micromirrors are arranged in a substantially planar manner at substantially the same position in the Z direction. The plurality of micromirrors are arranged, for example, substantially parallel to the X direction and the Y direction. The DMD mirror section 62 is arranged inside the through-hole 601 of the support substrate 60. The lower surface of the DMD mirror section 62 is located below the upper surface of the support substrate 60 around the through-hole 601 and above the lower surface of the support substrate 60 around the through-hole 601.

[0047] In the light modulation section 44, the light guided to the DMD 6 is incident on the DMD 6 from the (-Z) side of the DMD 6, reflected by the DMD mirror section 62, and guided to the (-Z) side of the DMD 6. That is, the (-Z) side of the DMD 6 (i.e., one side in the thickness direction) is the incident side (i.e., the front side) on which the light is incident, and the (+Z) side of the DMD 6 (i.e., the other side in the thickness direction) is the rear side located opposite to the incident side of the light. The main surface 612 on the (+Z) side of the DMD base section 61 is also the main surface on the (+Z) side of the DMD 6, and will be referred to as the "rear surface 612 of the DMD 6" in the following description. The main surface 612 on the (+Z) side of the DMD base section 61 is a substantially flat surface that is substantially perpendicular to the Z direction.

[0048] The DMD cover section 63 is a light-transmitting member, and covers the multiple micromirrors of the DMD mirror section 62 from below. The DMD cover section 63 is, for example, a substantially rectangular parallelepiped or substantially flat member with an opening on the (+Z) side. The DMD cover section 63 is attached to the main surface on the (-Z) side of the DMD base section 61. The DMD cover section 63 is, for example, a cover glass made of transparent quartz glass. Light incident on the DMD 6 passes through the DMD cover section 63 and enters the DMD mirror section 62. Light reflected by the DMD mirror section 62 passes through the DMD cover section 63 and is guided to the outside of the DMD 6.

[0049] The DMD cover part 63 is disposed inside the through-hole 601 of the support substrate 60. A main surface 631 (i.e., the lower surface) on the (-Z) side of the DMD cover part 63 is located lower than the upper surface of the support substrate 60 around the through-hole 601 and higher than the lower surface of the support substrate 60 around the through-hole 601. The main surface 631 on the (-Z) side of the DMD cover part 63 is a substantially flat surface that is substantially perpendicular to the Z direction. The through-hole 601 of the support substrate 60 opens to the (-Z) side and is a cover accommodating recess in which the cover part 63 is disposed.

[0050] The cooling unit 7 is a mechanism for cooling the DMD 6. The cooling unit 7 includes a rear cooling unit 71 and a front cooling unit 74. The rear cooling unit 71 is arranged on the (+Z) side of the DMD 6 (i.e., the opposite side to the substrate 9 shown in FIG. 1) at a position overlapping with the DMD 6 in a plan view. The rear cooling unit 71 contacts the (+Z) side main surface 612 (i.e., the upper surface) of the DMD base unit 61 and cools the DMD 6 from the DMD base unit 61 side by thermal conduction. The front cooling unit 74 is arranged on the (-Z) side of the DMD 6 and forms an airflow that flows along the (-Z) side main surface 631 (i.e., the lower surface) of the DMD cover unit 63 to cool the DMD 6 from the DMD cover unit 63 side. The (-Z) side main surface 631 of the DMD cover unit 63 is also the (-Z) side main surface of the DMD 6, and will be referred to as the "front surface 631 of the DMD 6" in the following description.

[0051] The back surface cooling part 71 is a substantially rectangular parallelepiped member having a flow path therein, and is a cooling jacket in which a fluid refrigerant flows through the flow path. The refrigerant is, for example, a liquid such as water. The refrigerant may be a liquid other than water, a gas, or a two-phase fluid in which a liquid and a gas are mixed. In this embodiment, the back surface cooling part 71 is a water-cooled jacket in which water flows through the flow path.

[0052] The back surface cooling section 71 has a protrusion at its lower end that protrudes downward from approximately the center in the X direction (i.e., toward the back surface 612 of the DMD 6). The lower end surface of the protrusion indirectly contacts the main surface 612 on the (+Z) side of the DMD base section 61 via a sheet-like heat transfer member 711. The heat transfer member 711 is a heat dissipation sheet with relatively high thermal conductivity. The shape of the back surface cooling section 71 may be modified in various ways. The back surface cooling section 71 may also be in direct contact with the main surface 612 on the (+Z) side of the DMD base section 61 without using the heat transfer member 711 or the like.

[0053] The rear surface cooling section 71 is urged against the main surface 612 on the (+Z) side of the DMD base section 61 (i.e., the rear surface 612 of the DMD 6) by the urging section 72 connected to the support substrate 60. This effectively suppresses a rise in temperature of the DMD base section 61. In other words, the rear surface cooling section 71 effectively cools the DMD 6 from the DMD base section 61 side.

[0054] The force with which the back surface cooling part 71 is urged against the main surface 612 on the (+Z) side of the DMD base part 61 (hereinafter also referred to as the "back surface urging force") has an upper limit set in relation to the structure of the DMD 6, etc. The structure of the urging part 72 is selected so that the back surface urging force does not exceed the upper limit. The thermal conductivity, thickness, etc. of the above-mentioned heat transfer member 711 are also set so that a sufficient heat transfer effect (i.e., heat dissipation effect) is obtained with the back surface urging force.

[0055] The housing member 8 is a covered cylindrical (i.e., box-shaped) member that opens downward. In the example shown in FIG. 4, the outer shape of the housing member 8 is a substantially rectangular parallelepiped shape, and includes a canopy portion 81 and a side wall portion 82. The canopy portion 81 of the housing member 8 is a substantially flat plate-shaped portion that extends substantially perpendicularly in the Z direction. The side wall portion 82 of the housing member 8 is a substantially flat plate-shaped portion that extends downward from the outer periphery of the canopy portion 81 over the entire circumference. The housing member 8 is attached to the upper surface of the support substrate 60, covering the back surface cooling portion 71, the biasing portion 72, etc. As a result, the back surface cooling portion 71, the biasing portion 72, etc. are accommodated in the internal space 80 of the housing member 8. The outer shape of the housing member 8 is not necessarily limited to a substantially rectangular parallelepiped shape, and may be another shape (for example, a substantially cylindrical shape, a substantially polygonal prism shape, a dome shape, etc.).

[0056] An air inlet 83 to which a duct extending from a dry gas supply source (not shown) is connected is provided in a side wall 82 of the storage member 8. A dry gas having a lower dew point than the atmosphere around the storage member 8 (i.e., the space outside the storage member 8) is supplied to the internal space 80 of the storage member 8 through the air inlet 83. This suppresses condensation on the surface of the back surface cooling section 71, etc., and suppresses moisture from adhering to the DMD 6. The dry gas supplied to the internal space 80 of the storage member 8 is exhausted to the outside of the storage member 8 through an exhaust port (not shown) provided at a distance from the air inlet 83 in the side wall 82 of the storage member 8. The above-mentioned dry gas is, for example, CDA (clean dry air). The dry gas is, for example, nitrogen (N 2 ) may be used.

[0057] The front cooling section 74 includes a first ejection section 76 and a second ejection section 77. The first ejection section 76 and the second ejection section 77 are connected to a gas supply source (not shown) and supply compressed gas to the DMD cover section 63 to suppress temperature rise of the DMD cover section 63 and the DMD mirror section 62. The gas contains, for example, unsaturated water vapor. In this embodiment, compressed air at room temperature (for example, 20°C to 23°C) is supplied from the gas supply source to the first ejection section 76 and the second ejection section 77. The pressure of the compressed air when it is sent out from the gas supply source is, for example, 0.3 MPaG to 0.5 MPaG, and preferably 0.3 MPaG to 0.4 MPaG. The amount of compressed air sent out from the gas supply source is, for example, 25 L / min (liters per minute) to 45 L / min, and preferably 25 L / min to 35 L / min. The compressed air has a pressure dew point of, for example, −40° C. or lower.

[0058] The first ejection section 76 includes a through flow passage 761 that extends from the inner circumferential surface 602 of the through hole 601 in the (-Y) direction inside the support substrate 60 and penetrates the support substrate 60 in the Y direction on the (-Y) side of the DMD cover section 63 and the DMD mirror section 62. An end of the through flow passage 761 on the (-Y) side is connected to the above-mentioned gas supply source via a pipe 762. The pipe 762 is, for example, a flexible pipe having flexibility. The flow passage cross-sectional area of ​​the pipe 762 (i.e., the area of ​​the internal space of the pipe 762 in a cross section perpendicular to the longitudinal direction of the pipe 762) is approximately constant over approximately the entire length of the pipe 762.

[0059] The gas supplied to the through-flow passage 761 from the gas supply source via the pipe 762 is ejected from an end opening on the (+Y) side of the through-flow passage 761 located on the inner circumferential surface 602 of the through-hole 601 into the space inside the through-hole 601 (i.e., the space surrounded by the inner circumferential surface 602 of the through-hole 601). In the following description, the end opening on the (+Y) side of the through-flow passage 761 is also referred to as a "first ejection port 763."

[0060] Fig. 6 is an enlarged perspective view of the first ejection port 763. The first ejection port 763 illustrated in Fig. 6 has a substantially rectangular shape in which the size in the circumferential direction along the inner circumferential surface 602 of the through hole 601 (i.e., the width in the substantially X direction) is larger than the size in the thickness direction of the DMD 6 (i.e., the height in the Z direction). The circumferential direction is a circumferential direction centered on the central axis of the through hole 601 extending in the Z direction (i.e., the up-down direction), and is a direction perpendicular to the Z direction. Note that the shape of the first ejection port 763 is not limited to a rectangle, and may be modified in various ways.

[0061] 3 to 5, the second ejection part 77 includes a through flow passage 771 that extends in the (+Y) direction from the inner circumferential surface 602 of the through hole 601 inside the support substrate 60 and penetrates the support substrate 60 in the Y direction on the (+Y) side of the DMD cover part 63 and the DMD mirror part 62. An end of the through flow passage 771 on the (+Y) side is connected to the above-mentioned gas supply source via a pipe 772. The pipe 772 is, for example, a flexible pipe having flexibility. The flow passage cross-sectional area of ​​the pipe 772 is approximately constant over approximately the entire length of the pipe 772.

[0062] The gas supplied to the through-flow passage 771 from the gas supply source via the pipe 772 is ejected from an end opening on the (-Y) side of the through-flow passage 771 located on the inner circumferential surface 602 of the through-hole 601 into the space inside the through-hole 601. In the following description, the end opening on the (-Y) side of the through-flow passage 771 is also referred to as a "second ejection port 773." The shape of the second ejection port 773 is substantially the same as the shape of the first ejection port 763 illustrated in FIG. 6.

[0063] 5, the first ejection port 763 is disposed near the end on the (-Y) side of the through hole 601, and the second ejection port 773 is disposed near the end on the (+Y) side of the through hole 601. In other words, the first ejection port 763 and the second ejection port 773 are substantially opposed to each other in the Y direction with the cover portion 63 and the DMD mirror portion 62 interposed therebetween. Note that the arrangement of the first ejection port 763 and the second ejection port 773 is not limited to the above example, and may be changed in various ways.

[0064] The first and second ejection ports 763 and 773 eject gas substantially parallel to the Y direction. The flow of gas ejected from the first ejection port 763 (hereinafter also referred to as the "first airflow") flows substantially parallel to the Y direction from the (-Y) side to the (+Y) side along the (-Z) side main surface 631 of the DMD cover section 63 (i.e., the front surface 631 of the DMD 6). The flow of gas ejected from the second ejection port 773 (hereinafter also referred to as the "second airflow") flows substantially parallel to the Y direction from the (+Y) side to the (-Y) side along the (-Z) side main surface 631 of the DMD cover section 63. In this embodiment, the first and second airflows flow substantially parallel to the (-Z) side main surface 631 of the DMD cover section 63. The temperatures of the first and second air currents are lower than the temperatures of DMD cover section 63 and DMD mirror section 62 of DMD 6 during operation, and therefore DMD cover section 63 and DMD mirror section 62 are suitably cooled. Furthermore, the first and second air currents are formed in the space inside through-hole 601, and gas is less likely to diffuse into the surrounding space, and therefore DMD cover section 63 and DMD mirror section 62 are even more suitably cooled.

[0065] 2, the incident direction of light incident on the DMD 6 from the illumination optical system 43 via the mirrors 471 and 472 is an upper right direction in FIG. 2 (i.e., an oblique direction proceeding toward the (+Y) side and the (+Z) side). In other words, the incident direction is inclined toward the (-Y) direction with respect to the Z direction (i.e., the thickness direction of the DMD base portion 61). In further other words, the incident direction is approximately parallel to the YZ plane, and is inclined with respect to both the Y direction and the Z direction within the YZ plane.

[0066] For this reason, while drawing on substrate 9 is being performed by drawing apparatus 1, the amount of light irradiated onto DMD mirror section 62 may become uneven in the Y direction (hereinafter also referred to as the "lateral direction"), which may cause unevenness in the temperature distribution in the Y direction of DMD mirror section 62. In front-side cooling section 74 illustrated in Figures 3 to 5, as described above, the flow direction of the airflow (i.e., the first airflow and the second airflow) formed by front-side cooling section 74 is approximately parallel to the Y direction, so that the temperature difference in the Y direction of DMD 6 caused by the unevenness in the temperature distribution is suppressed.

[0067] 5, the positions of the first and second ejection ports 763 and 773 in the X direction (i.e., the direction perpendicular to the lateral and thickness directions) are different. Specifically, with respect to an imaginary straight line L1 that passes through the center of the through hole 601 in a plan view and extends in the Y direction, the center of the first and second ejection ports 763 in the X direction is slightly shifted to the (+X) side, and the center of the second and second ejection ports 773 in the X direction is slightly shifted to the (-X) side. This prevents the first and second airflows from colliding with each other near the DMD cover section 63 (i.e., near the main surface 631 on the (-Z) side of the DMD cover section 63), and cooling of the DMD cover section 63 and the DMD mirror section 62 is suitably achieved.

[0068] 3 to 5, the through passage 761 of the first ejection part 76 includes a first ejection passage 764 and a first supply passage 765. The first ejection passage 764 is a passage extending in the (-Y) direction from the first ejection port 763, which is the end of the through passage 761 on the (+Y) side, and is connected to the first supply passage 765 at approximately the center of the through passage 761 in the Y direction. The first supply passage 765 is a passage extending in the (-Y) direction from the end of the first ejection passage 764 on the (-Y) side, and extends to the end of the through passage 761 on the (-Y) side to be connected to the above-mentioned piping 762.

[0069] That is, the through passage 761 of the first jetting part 76 is composed of a first jetting passage 764 and a first supply passage 765, and the first jetting passage 764 and the first supply passage 765 each include a part of the through passage 761. Also, a connection portion 766 between the first jetting passage 764 and the first supply passage 765 is located midway through the through passage 761. The connection portion 766 is a portion located at one position (i.e., one point) in the Y direction, and is not a portion that exists over a range of a predetermined length extending in the Y direction.

[0070] The shape of the cross section of the first ejection flow path 764 is substantially the same as the shape of the first ejection port 763, and is a substantially rectangular shape whose size in the X direction is greater than its size in the Z direction. The cross section of the first ejection flow path 764 is substantially constant over substantially the entire length of the first ejection flow path 764. The cross section of the first ejection flow path 764 is, for example, 7.065 mm 2 ~254.3mm 2 The shape of the flow path cross section of the first ejection flow path 764 refers to the shape of the first ejection flow path 764 in a cross section perpendicular to the longitudinal direction of the first ejection flow path 764 (i.e., the Y direction), and the flow path cross-sectional area of ​​the first ejection flow path 764 refers to the area of ​​the first ejection flow path 764 in a cross section perpendicular to the longitudinal direction of the first ejection flow path 764. The same applies to the other flow paths.

[0071] The shape of the flow path cross section of the first supply flow path 765 is a substantially rectangular shape smaller than the flow path cross section of the first ejection flow path 764. For example, the size of the flow path cross section of the first supply flow path 765 in the Z direction is substantially the same as the size of the flow path cross section of the first ejection flow path 764 in the Z direction, and the size of the flow path cross section of the first supply flow path 765 in the X direction is smaller than the size of the flow path cross section of the first ejection flow path 764 in the X direction. Therefore, the flow path cross section area of ​​the first supply flow path 765 is smaller than the flow path cross section area of ​​the first ejection flow path 764. The flow path cross section area of ​​the first supply flow path 765 is substantially constant over substantially the entire length of the first supply flow path 765.

[0072] The first supply flow path 765 indirectly connects the above-mentioned gas supply source and the first ejection flow path 764 via the pipe 762. The first supply flow path 765 guides compressed gas (e.g., compressed air) sent out from the gas supply source to the first ejection flow path 764. The first ejection flow path 764 ejects the gas that has flowed in from the first supply flow path 765 from the first ejection port 763 in the (+Y) direction, forming a first airflow along the main surface 631 on the (-Z) side of the DMD cover part 63. This causes the DMD 6 to be cooled from the DMD cover part 63 side.

[0073] In the first ejection part 76, the flow path cross-sectional area increases suddenly at the connection part 766 between the first supply flow path 765 and the first ejection flow path 764. Therefore, the gas flowing from the first supply flow path 765 to the first ejection flow path 764 may be adiabatically expanded and cooled when passing through the connection part 766. However, the connection part 766 is provided in the middle of the through flow path 761, and the change in the flow path cross-sectional area at the connection part 766 is not very large. For example, the flow path cross-sectional area of ​​the first ejection flow path 764 is 2.25 times or more and 20.25 times or less than the flow path cross-sectional area of ​​the first supply flow path 765. Therefore, the temperature drop of the gas passing through the connection part 766 is not very large, and condensation does not occur in the gas due to the temperature drop. Alternatively, even if condensation occurs in the gas, it immediately evaporates in the first supply flow path 765, and liquid water (i.e., mist, water droplets, etc.) is not substantially ejected from the first ejection port 763 toward the through hole 601.

[0074] In the first ejection part 76, the gas ejected from the first ejection flow path 764 toward the through hole 601 may also be adiabatically expanded and cooled when passing through the first ejection port 763. However, the first ejection flow path 764 is expanded from the first supply flow path 765 at the connection part 766, and has a relatively large flow path cross-sectional area. In addition, the pressure of the gas flowing through the first ejection flow path 764 is lower than the pressure of the gas flowing through the first supply flow path 765. Therefore, the amount of temperature drop of the gas passing through the first ejection port 763 is not very large, and condensation does not occur in the gas due to the temperature drop. Or, even if condensation occurs in the gas, it immediately evaporates. Therefore, liquid water (i.e., mist, water droplets, etc.) is prevented or suppressed from adhering to the main surface 631 on the (-Z) side of the DMD cover part 63.

[0075] On the other hand, if the first ejection passage 764 is not provided in the first ejection part 76 and the first supply passage 765 extends to the inner circumferential surface 602 of the through hole 601, the area of ​​the end opening (i.e., the ejection port corresponding to the above-mentioned first ejection port 763) on the (+Y) side of the first supply passage 765 and the flow path cross-sectional area of ​​the first supply passage 765 in the vicinity of the end opening become relatively small. Therefore, the gas ejected from the first supply passage 765 toward the through hole 601 may be adiabatically expanded and significantly decreased in temperature when passing through the end opening. As a result, the gas may condense due to the temperature decrease, and liquid water (i.e., mist, water droplets, etc.) may adhere to the main surface 631 on the (-Z) side of the DMD cover part 63.

[0076] 3 to 5, as described above, the first supply flow path 765 and the first ejection flow path 764 are provided, so that the DMD 6 can be cooled from the DMD cover part 63 side while suppressing condensation on the DMD cover part 63. From the viewpoint of suitably suppressing condensation on the DMD cover part 63, the flow path cross-sectional area of ​​the first ejection flow path 764 is preferably 2.25 times or more, and more preferably 4 times or more, the flow path cross-sectional area of ​​the first supply flow path 765.

[0077] The structure of the second ejection part 77 is substantially the same as the above-mentioned structure of the first ejection part 76. Specifically, the through passage 771 of the second ejection part 77 includes a second ejection passage 774 and a second supply passage 775. The second ejection passage 774 is a passage extending in the (+Y) direction from the second ejection port 773, which is the end of the through passage 771 on the (-Y) side, and is connected to the second supply passage 775 at substantially the center of the through passage 771 in the Y direction. The second supply passage 775 is a passage extending in the (+Y) direction from the end of the second ejection passage 774 on the (+Y) side, and extends to the end of the through passage 771 on the (+Y) side and is connected to the above-mentioned piping 772.

[0078] That is, the through passage 771 of the second ejection part 77 is composed of a second ejection passage 774 and a second supply passage 775, and the second ejection passage 774 and the second supply passage 775 each include a part of the through passage 771. Also, a connection portion 776 between the second ejection passage 774 and the second supply passage 775 is located midway through the through passage 771. The connection portion 776 is a portion located at one position (i.e., one point) in the Y direction, and is not a portion that exists over a range of a predetermined length extending in the Y direction.

[0079] The shape of the flow passage cross section of the second ejection flow passage 774 is substantially the same as the shape of the second ejection port 773, and is a substantially rectangular shape whose size in the X direction is larger than the size in the Z direction. The flow passage cross section area of ​​the second ejection flow passage 774 is substantially constant over substantially the entire length of the second ejection flow passage 774. The flow passage cross section shape of the second supply flow passage 775 is substantially rectangular and smaller than the flow passage cross section of the second ejection flow passage 774. For example, the size of the flow passage cross section of the second supply flow passage 775 in the Z direction is substantially the same as the size of the flow passage cross section of the second ejection flow passage 774 in the Z direction, and the size of the flow passage cross section of the second supply flow passage 775 in the X direction is smaller than the size of the flow passage cross section of the second ejection flow passage 774 in the X direction. Therefore, the flow passage cross section area of ​​the second supply flow passage 775 is smaller than the flow passage cross section area of ​​the second ejection flow passage 774. The flow passage cross section area of ​​the second supply flow passage 775 is substantially constant over substantially the entire length of the second supply flow passage 775.

[0080] The second supply flow path 775 indirectly connects the above-mentioned gas supply source and the second ejection flow path 774 via the pipe 772. The second supply flow path 775 guides compressed gas (e.g., compressed air) sent out from the gas supply source to the second ejection flow path 774. The second ejection flow path 774 ejects the gas that has flowed in from the second supply flow path 775 from the second ejection port 773 in the (-Y) direction, forming a second airflow along the main surface 631 on the (-Z) side of the DMD cover part 63. This causes the DMD 6 to be cooled from the DMD cover part 63 side.

[0081] In the second ejection part 77, the flow path cross-sectional area increases suddenly at the connection part 776 between the second supply flow path 775 and the second ejection flow path 774. Therefore, the gas flowing from the second supply flow path 775 to the second ejection flow path 774 may be adiabatically expanded and cooled when passing through the connection part 776. However, the connection part 776 is provided in the middle of the through flow path 771, and the change in the flow path cross-sectional area at the connection part 776 is not very large. For example, the flow path cross-sectional area of ​​the second ejection flow path 774 is 2.25 times or more and 20.25 times or less than the flow path cross-sectional area of ​​the second supply flow path 775. Therefore, the temperature drop of the gas passing through the connection part 776 is not very large, and condensation does not occur in the gas due to the temperature drop. Alternatively, even if condensation occurs in the gas, it immediately evaporates in the second supply flow path 775, and liquid water (i.e., mist, water droplets, etc.) is not substantially ejected from the second ejection port 773 toward the through hole 601.

[0082] In the second ejection part 77, the gas ejected from the second ejection flow path 774 toward the through hole 601 may also be adiabatically expanded and cooled when passing through the second ejection port 773. However, the second ejection flow path 774 is expanded from the second supply flow path 775 at the connection part 776, and has a relatively large flow path cross-sectional area. In addition, the pressure of the gas flowing through the second ejection flow path 774 is lower than the pressure of the gas flowing through the second supply flow path 775. Therefore, the amount of temperature drop of the gas passing through the second ejection port 773 is not very large, and condensation does not occur in the gas due to the temperature drop. Or, even if condensation occurs in the gas, it immediately evaporates. Therefore, liquid water (i.e., mist, water droplets, etc.) is prevented or suppressed from adhering to the main surface 631 on the (-Z) side of the DMD cover part 63.

[0083] On the other hand, if the second ejection passage 774 is not provided in the second ejection part 77 and the second supply passage 775 extends to the inner circumferential surface 602 of the through hole 601, the area of ​​the end opening (i.e., the ejection port corresponding to the above-mentioned second ejection port 773) on the (-Y) side of the second supply passage 775 and the flow path cross-sectional area of ​​the second supply passage 775 in the vicinity of the end opening become relatively small. Therefore, the gas ejected from the second supply passage 775 toward the through hole 601 may be adiabatically expanded and significantly decreased in temperature when passing through the end opening. As a result, the gas may condense due to the temperature decrease, and liquid water (i.e., mist, water droplets, etc.) may adhere to the main surface 631 on the (-Z) side of the DMD cover part 63.

[0084] 3 to 5, as described above, by providing the second supply flow path 775 and the second ejection flow path 774, it is possible to cool the DMD 6 from the DMD cover part 63 side while suppressing condensation on the DMD cover part 63. From the viewpoint of suitably suppressing condensation on the DMD cover part 63, the flow path cross-sectional area of ​​the second ejection flow path 774 is preferably 2.25 times or more, and more preferably 4 times or more, the flow path cross-sectional area of ​​the second supply flow path 775.

[0085] In the above example, the first ejection flow passage 764 of the first ejection part 76 includes only a part of the through flow passage 761, but is not limited thereto. For example, in the first ejection part 76, the entire through flow passage 761 may be the first ejection flow passage 764. In this case, the flow passage cross-sectional area of ​​the through flow passage 761 (i.e., the flow passage cross-sectional area of ​​the first ejection flow passage 764) is substantially constant over substantially the entire length of the through flow passage 761. In addition, a portion of the pipe 762 near the end connected to the end of the through flow passage 761 on the (-Y) side, or substantially the entire pipe 762, becomes the first supply flow passage 765 having a flow passage cross-sectional area smaller than that of the first ejection flow passage 764. In other words, the connection part 766 between the first supply flow passage 765 and the first ejection flow passage 764 is located at the end of the through flow passage 761 on the opposite side to the through hole 601. The same applies to the second ejection flow passage 774 and the second supply flow passage 775 of the second ejection part 77.

[0086] In the above example, the connection portion 766 between the first ejection flow path 764 and the first supply flow path 765 in the first ejection part 76 is a portion located at one position (i.e., one point) in the Y direction, but is not limited thereto and may be a portion existing over a range of a predetermined length extending in the Y direction. For example, the connection portion 766 may be a portion in which the flow path cross-sectional area gradually increases or intermittently increases from the end of the (+Y) side of the first supply flow path 765 toward the (+Y) direction. In this case, the first ejection flow path 764 is indirectly connected to the first supply flow path 765 via the connection portion 766, and extends from the end of the (+Y) side of the connection portion 766 to the inner circumferential surface 602 of the through hole 601. The same applies to the second ejection flow path 774, the connection portion 776, and the second supply flow path 775 of the second ejection part 77.

[0087] As described above, the optical device 10 that irradiates the object (substrate 9 in the above example) with modulated light includes the illumination optical system 43, the light modulation unit 44, and the projection optical system 45. Light emitted from the light source 421 is incident on the illumination optical system 43. The light modulation unit 44 modulates the light guided by the illumination optical system 43. The projection optical system 45 guides the light modulated by the light modulation unit 44 to the object. The light modulation unit 44 includes a digital micromirror device 6 (i.e., DMD 6) and a cooling unit 7 that cools the DMD 6. The DMD 6 includes a DMD base unit 61, a DMD mirror unit 62, and a DMD cover unit 63. The DMD mirror unit 62 includes a plurality of movable micromirrors arranged in a matrix on one side in the thickness direction of the DMD base unit 61 (the (-Z) side in the above example). The DMD cover unit 63 covers the DMD mirror unit 62 from the one side in the thickness direction.

[0088] The cooling unit 7 includes an ejection flow path (i.e., a first ejection flow path 764) and a supply flow path (i.e., a first supply flow path 765). The first ejection flow path 764 ejects gas from an ejection port (i.e., a first ejection port 763) to form an airflow along the main surface 631 on the one side in the thickness direction of the DMD cover part 63, thereby cooling the DMD 6. The first supply flow path 765 connects a gas supply source and the first ejection flow path 764, and guides compressed gas (e.g., compressed air) delivered from the gas supply source to the first ejection flow path 764. The flow path cross-sectional area of ​​the first supply flow path 765 is smaller than the flow path cross-sectional area of ​​the first ejection flow path 764.

[0089] This allows the DMD 6 to be cooled from the DMD cover section 63 side while suppressing condensation due to adiabatic expansion of gas near the first ejection port 763, as described above. As a result, it is possible to suppress the adhesion of liquid water such as mist or droplets (hereinafter also referred to as "droplets, etc.") to the main surface 631 on the (-Z) side of the DMD cover section 63, which prevents the irradiation of light onto the target object from being hindered. In addition, the first supply flow path 765 and the pipe 762 connecting the first ejection flow path 764 and the gas supply source can be made relatively thin (i.e., the cross-sectional area of ​​the flow path can be made small), which improves the degree of freedom in the arrangement of the first supply flow path 765 and the handling (i.e., installation) of the pipe 762. As a result, the optical device 10 can be made compact.

[0090] As described above, the optical modulation section 44 preferably further includes a device holding section (support substrate 60 in the above example) that holds the DMD 6. The device holding section includes a cover accommodating recess (i.e., through hole 601) that opens to the one side in the thickness direction (the (-Z) side in the above example). The DMD cover section 63 is disposed inside the through hole 601. The first ejection flow path 764 preferably includes at least a part of the through flow path 761 that penetrates the device holding section from the inner circumferential surface 602 of the through hole 601. In addition, the connection section 766 between the first supply flow path 765 and the first ejection flow path 764 is preferably located at the end of the through flow path 761 on the opposite side to the through hole 601, or in the middle of the through flow path 761. This eliminates the need to arrange the first ejection flow path 764, which has a relatively large flow path cross-sectional area, around the device holding section (support substrate 60 in the above example), and therefore the optical device 10 can be further miniaturized.

[0091] As described above, it is preferable that the size of the first ejection port 763 in the direction perpendicular to the thickness direction (X direction in the above example) is larger than the size of the first ejection port 763 in the thickness direction (Z direction in the above example). This makes it possible to form an airflow over a wide range on the main surface 631 on the (-Z) side of the DMD cover section 63. As a result, it is possible to suitably cool the DMD 6 from the DMD cover section 63 side while suppressing the above-mentioned condensation.

[0092] As described above, the flow path cross-sectional area of ​​the first ejection flow path 764 is preferably 2.25 times or more the flow path cross-sectional area of ​​the first supply flow path 765. This makes it possible to preferably suppress the above-mentioned condensation, and therefore to preferably suppress adhesion of water droplets and the like to the main surface 631 on the (-Z) side of the DMD cover part 63.

[0093] As described above, the flow direction of the airflow formed by the cooling unit 7 (specifically, the front cooling unit 74 of the cooling unit 7) is preferably parallel to the main surface 631 on the one side in the thickness direction of the DMD cover unit 63. This makes it possible to suitably suppress the stagnation of the atmosphere in the vicinity of the main surface 631 on the (-Z) side of the DMD cover unit 63, and as a result, it is possible to suitably cool the DMD 6. Even if the airflow contains water droplets or the like, it is possible to suppress the adhesion of water droplets or the like to the main surface 631 of the DMD cover unit 63, compared to the case in which the airflow is blown from the first nozzle 763 toward the main surface 631 on the (-Z) side of the DMD cover unit 63.

[0094] As described above, the direction of incidence of light on the DMD 6 is inclined in the lateral direction (Y direction in the above example) perpendicular to the thickness direction (Z direction in the above example) with respect to the thickness direction. The flow direction of the airflow formed by the cooling unit 7 is preferably parallel to the lateral direction. This makes it possible to suppress the lateral temperature difference in the DMD 6 as described above.

[0095] As described above, it is preferable that the cooling unit 7 further includes another ejection flow path (i.e., the second ejection flow path 774) and another supply flow path (i.e., the second supply flow path 775). The second ejection flow path 774 ejects gas from another ejection port (i.e., the second ejection port 773) to form another air flow along the main surface 631 on the one side in the thickness direction of the DMD cover part 63 (the (-Z) side in the above example), thereby cooling the DMD 6. The second supply flow path 775 connects the gas supply source and the second ejection flow path 774, and guides the compressed gas (e.g., compressed air) sent from the gas supply source to the second ejection flow path 774. The flow path cross-sectional area of ​​the second supply flow path 775 is smaller than the flow path cross-sectional area of ​​the second ejection flow path 774. Preferably, the airflow (i.e., the first airflow) caused by the gas ejected from the first ejection port 763 flows from one side to the other side in the horizontal direction perpendicular to the thickness direction (in the above example, from the (-Y) side to the (+Y) side), and the other airflow (i.e., the second airflow) caused by the gas ejected from the second ejection port 773 flows from the other side to one side in the horizontal direction (in the above example, from the (+Y) side to the (-Y) side). This allows the gas from the cooling unit 7 to be evenly supplied to substantially the entire main surface 631 on the (-Z) side of the DMD cover unit 63. As a result, the DMD 6 can be suitably cooled from the DMD cover unit 63 side, and the temperature difference in the horizontal direction in the DMD 6 can be further suppressed.

[0096] As described above, it is preferable that the positions of the first and second air outlets 763 and 773 in the direction perpendicular to the thickness direction and the lateral direction (the X direction in the above example) are different from each other. This makes it possible to suppress collision of the first and second air currents near the DMD cover part 63, and therefore makes it possible to suitably cool the DMD 6 from the DMD cover part 63 side.

[0097] The above-mentioned drawing apparatus 1 draws a pattern by irradiating light onto the substrate 9. The drawing apparatus 1 includes a stage 21, the above-mentioned optical device 10, and a scanning mechanism (stage moving mechanism 22 in the above-mentioned example). The stage 21 holds the substrate 9. The optical device 10 irradiates the substrate 9 with modulated light. The scanning mechanism moves the stage 21 relative to the optical device 10 in a scanning direction (Y direction in the above-mentioned example) parallel to the main surface (i.e., the upper surface 91) of the substrate 9. As described above, the optical device 10 can prevent water droplets or the like from adhering to the main surface 631 on the (-Z) side of the DMD cover part 63, which would hinder the irradiation of light onto the target object. Therefore, the drawing apparatus 1 can suitably draw a pattern onto the substrate 9.

[0098] Next, the relationship between the ratio of the flow path cross-sectional area of ​​the first ejection flow path 764 to the flow path cross-sectional area of ​​the first supply flow path 765 (hereinafter also referred to as the "flow path cross-sectional area ratio") and the adhesion of water droplets, etc. to the main surface 631 of the DMD cover portion 63 will be explained with reference to Table 1.

[0099] [Table 1]

[0100] Comparative Examples 1 to 6 and Examples 1 to 18 in Table 1 are the results of experiments carried out using an experimental device having a structure substantially similar to that of the above-mentioned optical modulation section 44, in which the rear surface cooling section 71 and the second ejection section 77 are omitted from the cooling section 7. In the experimental device, the cross-sectional shapes of the first ejection flow path 764 and the first supply flow path 765 are substantially circular. The diameter of the cross-sectional shape of the first supply flow path 765 is 2 mm.

[0101] "Nozzle diameter (mm)" in Table 1 is the diameter of first nozzle 763 which is the end opening of first ejection flow path 764, and is the same as the diameter of the flow path cross section of first ejection flow path 764. "Flow path cross-sectional area ratio" in Table 1 is the ratio of the flow path cross-sectional area of ​​first ejection flow path 764 to the flow path cross-sectional area of ​​first supply flow path 765, as described above. "Gas pressure (MPaG)" and "flow rate (L / min)" in Table 1 are the pressure of the compressed air when it is sent out from the above-mentioned gas supply source, and the amount of compressed air sent out from the gas supply source, respectively.

[0102] The "rating" in Table 1 indicates the result of visually checking the adhesion of water droplets, etc., to the main surface 631 of the DMD cover 63. The rating "E" (Excellent) means that no adhesion of water droplets, etc., to the DMD cover 63 was confirmed. The rating "G" (Good) means that adhesion of water droplets, etc., to the DMD cover 63 was confirmed, but the adhesion of the water droplets, etc., was very slight. The adhesion state of water droplets, etc. in the rating "G" is a state in which it is expected that the amount of light reflected from the DMD can be maintained at or above a desired value even if the above-mentioned optical device 10 is operated under the same conditions as in the experiment for a predetermined service life or more. The rating "P" (Poor) means that adhesion of water droplets, etc., to the DMD cover 63 was confirmed over a relatively wide range. The adhesion state of water droplets, etc. in the rating "P" is a state in which it is expected that the amount of light reflected from the DMD will become smaller than a desired value sooner than the predetermined service life when the above-mentioned optical device 10 is operated under the same conditions as in the experiment.

[0103] In Comparative Examples 1 to 6, the nozzle diameter is 2 mm, and the flow path cross-sectional area ratio is 1. In Comparative Examples 1 to 3, the gas pressure is 0.4 MPaG, and in Comparative Examples 4 to 6, the gas pressure is 0.5 MPaG. The flow rates in Comparative Examples 1 to 3 are 25 L / min, 35 L / min, and 45 L / min, respectively. The flow rates in Comparative Examples 4 to 6 are 25 L / min, 35 L / min, and 45 L / min, respectively.

[0104] Comparative Examples 1 to 6 were evaluated as "P." In Comparative Examples 1 to 6, since the flow path cross-sectional area ratio was 1 (i.e., the flow path cross-sectional area of ​​the first ejection flow path 764 was the same as the flow path cross-sectional area of ​​the first supply flow path 765), the compressed air ejected from the first ejection port 763 was significantly cooled due to adiabatic expansion, etc., as described above, and water droplets and the like adhered to the DMD cover portion 63 over a wide area.

[0105] In Examples 1 to 6, the nozzle diameter is 3 mm, and the flow path cross-sectional area ratio is 2.25. In Examples 1 to 3, the gas pressure is 0.4 MPaG, and in Examples 4 to 6, the gas pressure is 0.5 MPaG. The flow rates in Examples 1 to 3 are 25 L / min, 35 L / min, and 45 L / min, respectively. The flow rates in Examples 4 to 6 are 25 L / min, 35 L / min, and 45 L / min, respectively.

[0106] Examples 1 to 6 were evaluated as “E” or “G.” In Examples 1 to 6, the flow path cross-sectional area of ​​the first ejection flow path 764 was larger than the flow path cross-sectional area of ​​the first supply flow path 765, and therefore, as described above, the temperature drop of the compressed air ejected from the first ejection port 763 was suppressed, and adhesion of water droplets and the like to the DMD cover portion 63 was prevented or suppressed.

[0107] In Examples 7 to 12, the nozzle diameter is 4 mm, and the flow path cross-sectional area ratio is 4. In Examples 7 to 9, the gas pressure is 0.4 MPaG, and in Examples 10 to 12, the gas pressure is 0.5 MPaG. The flow rates in Examples 7 to 9 are 25 L / min, 35 L / min, and 45 L / min, respectively. The flow rates in Examples 10 to 12 are 25 L / min, 35 L / min, and 45 L / min, respectively.

[0108] Examples 7 to 12 were evaluated as “E” or “G.” In Examples 7 to 12, the flow path cross-sectional area of ​​the first ejection flow path 764 was larger than the flow path cross-sectional area of ​​the first supply flow path 765, and therefore, as described above, the decrease in temperature of the compressed air ejected from the first ejection port 763 was suppressed, and adhesion of water droplets and the like to the DMD cover portion 63 was prevented or suppressed.

[0109] In Examples 13 to 18, the nozzle diameter is 9 mm, and the flow path cross-sectional area ratio is 20.25. In Examples 13 to 15, the gas pressure is 0.4 MPaG, and in Examples 16 to 18, the gas pressure is 0.5 MPaG. The flow rates in Examples 13 to 15 are 25 L / min, 35 L / min, and 45 L / min, respectively. The flow rates in Examples 16 to 18 are 25 L / min, 35 L / min, and 45 L / min, respectively.

[0110] Examples 13 to 18 were evaluated as "E." In Examples 13 to 18, the flow path cross-sectional area of ​​the first ejection flow path 764 was larger than the flow path cross-sectional area of ​​the first supply flow path 765, and therefore, as described above, the temperature drop of the compressed air ejected from the first ejection port 763 was suppressed, and adhesion of water droplets and the like to the DMD cover portion 63 was prevented.

[0111] The optical device 10 and the imaging device 1 described above can be modified in various ways.

[0112] For example, the first airflow formed by the gas ejected from the first nozzle 763 only needs to flow along the main surface 631 on the (-Z) side of the DMD cover part 63, and does not necessarily need to flow parallel to the main surface 631. The same applies to the second airflow formed by the gas ejected from the second nozzle 773.

[0113] In the first jetting section 76, the flow path cross-sectional area of ​​the first jetting flow path 764 may be less than 2.25 times the flow path cross-sectional area of ​​the first supply flow path 765. Similarly, in the second jetting section 77, the flow path cross-sectional area of ​​the second jetting flow path 774 may be less than 2.25 times the flow path cross-sectional area of ​​the second supply flow path 775.

[0114] In the first ejection section 76, the flow path cross-sectional area of ​​the first ejection flow path 764 and the flow path cross-sectional area of ​​the first supply flow path 765 do not necessarily need to be constant over the entire length in the longitudinal direction, and may vary in a part in the longitudinal direction. In this case, when determining the ratio of the flow path cross-sectional area of ​​the first ejection flow path 764 to the flow path cross-sectional area of ​​the first supply flow path 765, the representative flow path cross-sectional areas of the first ejection flow path 764 and the first supply flow path 765 are used. The representative flow path cross-sectional area of ​​the first ejection flow path 764 is the flow path cross-sectional area of ​​the first ejection flow path 764 at the first ejection port 763 (i.e., the opening area of ​​the first ejection port 763). The representative flow path cross-sectional area of ​​the first supply flow path 765 is the flow path cross-sectional area of ​​the first supply flow path 765 at the boundary with the connection portion 766. The same applies to the second ejection section 77.

[0115] In the first ejection part 76, a nozzle protruding from the end of the through-flow passage 761 on the through hole 601 side toward the (+Y) side may be provided. In this case, the nozzle is included in the first ejection flow passage 764, and the end of the nozzle on the (+Y) side becomes the first ejection port 763. In addition, when the nozzle is provided, the first ejection flow passage 764 is configured only by the nozzle, and the entire through passage 761 may be the first supply flow passage 765 having a flow passage cross-sectional area smaller than that of the first ejection flow passage 764. The second ejection part 77 is substantially the same.

[0116] In the first jetting part 76, the first jetting flow path 764 and the first supply flow path 765 do not necessarily include a through flow path penetrating the support substrate 60, and may be, for example, a flexible pipe or the like disposed around the support substrate 60. The same applies to the second jetting part 77.

[0117] In the front surface cooling section 74, the positions of the first and second ejection ports 763 and 773 are not limited to the above example and may be changed in various ways. For example, the center in the X direction of the first ejection port 763 and / or the center in the X direction of the second ejection port 773 may be disposed on the above-mentioned imaginary straight line L1 (see FIG. 5). Also, for example, the first ejection port 763 may be disposed near the end of the through hole 601 on the (+X) side, and the second ejection port 773 may be disposed near the end of the through hole 601 on the (-X) side.

[0118] As described above, the shape of the first jetting nozzle 763 may be changed in various ways. For example, the height of the first jetting nozzle 763 in the Z direction may be approximately the same as the width in the X direction, or may be greater than the width. Also, for example, the shape of the first jetting nozzle 763 when viewed parallel to the Y direction may be approximately circular or approximately oval. The same applies to the shape of the second jetting nozzle 773.

[0119] Furthermore, one of the first ejection port 763 and the second ejection port 773 may be omitted from the front surface cooling portion 74. Alternatively, in addition to the first ejection port 763 and the second ejection port 773, another ejection port may be provided.

[0120] In the optical device 10, the shape, structure, type, and the like of the back surface cooling part 71 may be changed in various ways. For example, the shape of the back surface cooling part 71 may be substantially cylindrical or substantially polygonal prism, or may be substantially flat plate-like. The back surface cooling part 71 does not necessarily have to be a water-cooled jacket, and may be a Peltier element or the like. In the optical device 10, the back surface cooling part 71 may be omitted.

[0121] In the imaging device 1, the stage 21 may be moved relatively in the main scanning direction with respect to the imaging head 41 by the first moving mechanism 23. Therefore, for example, the stage 21 may be fixed, and above the stage 21, the imaging head 41 may be moved in the main scanning direction by the first moving mechanism 23. Similarly, the imaging head 41 may be moved in the sub-scanning direction by the second moving mechanism 24.

[0122] The above-mentioned substrate 9 is not necessarily limited to a printed circuit board. The drawing device 1 may draw a pattern on, for example, a semiconductor substrate, a substrate for a semiconductor package, a glass substrate for a flat panel display device such as a liquid crystal display device or a plasma display device, a glass substrate for a photomask, a substrate for a solar panel, or the like.

[0123] The optical device 10 may be used as a device that irradiates modulated light onto a substrate 9 in a drawing device having a structure different from that of the above-described drawing device 1. Alternatively, the optical device 10 may be used to irradiate an object with modulated light in a device other than a drawing device.

[0124] The configurations in the above-described embodiment and each of the modified examples may be combined as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0125] 1 Drawing device 6 DMD (Digital Micromirror Device) 7 Cooling section 9 Substrate 10 Optical equipment 21 Stage 22 Stage movement mechanism 43 Illumination optical system 44 Optical modulation section 45 Projection optical system 60 Support substrate 61 DMD base section 62 DMD mirror section 63 DMD cover part 91 (Platform) Top 421 Light source 601 Through hole 602 Inner surface 612 (DMD base) Main surface 631 (DMD cover) main surface 761 Through passage 763 No.1 spout 764 First jet passage 765 First supply channel 766 Connection 771 Through passage 773 2nd spout 774 Second jet passage 775 Second Supply Channel 776 Connection

Claims

1. An optical device for illuminating an object with modulated light, comprising: an illumination optical system into which light emitted from a light source is incident; a light modulation unit that modulates the light guided by the illumination optical system; a projection optical system that guides the light modulated by the light modulation unit to an object; Equipped with The optical modulation unit includes: A digital micromirror device; a cooling unit that cools the digital micromirror device; Equipped with The digital micromirror device is A DMD base portion; a DMD mirror section including a plurality of movable micromirrors arranged in a matrix on one side of the DMD base section in a thickness direction; a DMD cover portion that covers the DMD mirror portion from the one side in the thickness direction; Equipped with The cooling unit includes: an ejection flow path that ejects gas from an ejection port to form an airflow along the main surface on the one side in the thickness direction of the DMD cover portion, thereby cooling the digital micromirror device; a supply flow path that connects a gas supply source and the ejection flow path to guide compressed gas discharged from the gas supply source to the ejection flow path and has a flow path cross-sectional area smaller than that of the ejection flow path; An optical device comprising:

2. 2. The optical device according to claim 1, the light modulation unit further includes a device holder that holds the digital micromirror device; the device holding portion includes a cover accommodating recess that opens to the one side in the thickness direction and into which the DMD cover is disposed, the ejection passage includes at least a portion of a through passage that penetrates the device holding portion from an inner circumferential surface of the cover accommodating recess, The connection portion between the supply flow passage and the ejection flow passage is an optical device located at an end of the through flow passage opposite to the cover accommodating recess, or midway along the through flow passage.

3. 2. The optical device according to claim 1, An optical device in which the size of the nozzle in a direction perpendicular to the thickness direction is larger than the size of the nozzle in the thickness direction.

4. 2. The optical device according to claim 1, An optical device, wherein a flow passage cross-sectional area of ​​the ejection flow passage is 2.25 times or more larger than a flow passage cross-sectional area of ​​the supply flow passage.

5. 2. The optical device according to claim 1, An optical device, wherein the flow direction of the airflow formed by the cooling section is parallel to the main surface on the one side in the thickness direction of the DMD cover section.

6. 2. The optical device according to claim 1, an incident direction of light on the digital micromirror device is inclined with respect to the thickness direction in a lateral direction perpendicular to the thickness direction; An optical device, wherein the flow direction of the airflow formed by the cooling section is parallel to the lateral direction.

7. 2. The optical device according to claim 1, The cooling unit includes: another ejection flow path for ejecting gas from another ejection port to form another airflow along the main surface on the one side in the thickness direction of the DMD cover portion, thereby cooling the digital micromirror device; another supply flow path that connects a gas supply source and the other ejection flow path to guide compressed gas discharged from the gas supply source to the other ejection flow path and has a flow path cross-sectional area smaller than that of the other ejection flow path; Further equipped with the airflow caused by the gas ejected from the ejection port flows from one side to the other side in a lateral direction perpendicular to the thickness direction, An optical device in which the other air flow caused by the gas ejected from the other ejection port flows from the other side to the one side in the lateral direction.

8. 8. The optical device according to claim 7, An optical device in which the positions of the jet outlet and the other jet outlet in a direction perpendicular to the thickness direction and the lateral direction are different from each other.

9. A drawing apparatus that draws a pattern by irradiating a substrate with light, A stage for holding the substrate; an optical device according to claim 1 for irradiating the substrate with modulated light; a scanning mechanism that moves the stage relative to the optical device in a scanning direction parallel to a main surface of the substrate; A drawing device comprising:

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