JP2008300683A - Cleaning apparatus and method, and exposure apparatus having cleaning apparatus - Google Patents

Abstract

A cleaning apparatus and method for increasing the removal rate of fine particles, maintaining the throughput of an exposure apparatus, and reducing damage to a surface to be cleaned, and an exposure apparatus having the cleaning apparatus.
A reticle is exposed to a pattern on a reticle disposed in a vacuum environment via a projection optical system, and the reticle is cleaned by irradiating the reticle with a laser beam in a vacuum environment. In the exposure apparatus 100 having a cleaning apparatus, the cleaning apparatus includes an irradiation unit that irradiates the laser beam L with respect to the pattern surface 2a of the reticle 2 at an angle in a range of 1 ° to 45 °, and the irradiation unit includes: Exposure in which the laser beam L is incident from a plurality of incident directions having different incident directions around the normal line of the pattern surface 2a while maintaining the incident angle of the laser beam L with respect to the pattern surface 2a within the above range. An apparatus 100 is provided.
[Selection] Figure 1

Description

  The present invention relates to a cleaning apparatus and method, and an exposure apparatus having the cleaning apparatus.

  2. Description of the Related Art Projection exposure apparatuses that expose an original (mask or reticle, hereinafter referred to as “reticle”) pattern onto a substrate (wafer) by a projection optical system have been used in the past, and high-resolution exposure apparatuses are increasingly required. It is effective to shorten the wavelength of the exposure light as one means to meet such a demand. Therefore, in recent years, an EUV exposure apparatus using extreme ultraviolet (EUV) light having a wavelength of about 10 nm to 20 nm, which is shorter than ultraviolet light, has been proposed.

  The EUV exposure apparatus generally uses a reflective optical system that does not use a refractive member because the light absorption rate by the substance is high in the EUV light wavelength region. For this reason, the pellicle used for the refractive optical system cannot be mounted on the reticle, and the reticle pattern surface is exposed. Here, the “pellicle” is a thin film having a high transmittance covering the reticle pattern surface, and prevents fine particles (particles) from adhering to the pattern surface. The fine particles come from a driving unit that drives the reticle and a residual gas. If fine particles adhere to the reticle pattern surface, transfer defects (defects) are caused. Therefore, it is necessary to remove the fine particles from the reticle pattern surface.

  Therefore, Patent Documents 1 and 2 propose a method of removing fine particles by irradiating pulsed laser light.

There exists patent document 3 as another prior art.
JP 2000-088999 A (paragraphs 0041, 0044, 0045) JP 2003-224667 A (paragraphs 0038, 0050, 0051) JP 2006-114650 A

  However, Patent Document 2 irradiates the surface to be cleaned with a laser beam irradiation angle equal to or less than the Brewster angle. However, at an incident angle near the vertical to the surface to be cleaned, the reflectivity of the metal surface generally decreases and the absorption of the laser beam increases, so that the surface to be cleaned becomes more damaged. For this reason, it is conceivable to introduce oblique incident light into the surface to be cleaned. However, since the reticle pattern has irregularities, the laser beam may be blocked by the convex portions of the reticle pattern and may not reach the fine particles in the concave portions. . In particular, in Patent Document 2, since the incident angle of laser light changes from place to place, such a problem is remarkable.

  Further, Patent Documents 1 and 2 propose introducing gas into the vacuum chamber during cleaning. However, when the pressure is increased by introducing gas, the fine particles detached from the reticle surface are decelerated by the fluid resistance due to the gas and reattached to the reticle surface, so that the removal rate decreases. If gas is introduced, the vacuum environment of the vacuum chamber of the EUV exposure apparatus is destroyed and the throughput of the exposure apparatus is reduced.

  Further, there are cases where the fineness adheres to the reticle chuck that holds the reticle on the reticle stage and the wafer chuck that holds the wafer on the wafer stage, thereby reducing the flatness when holding the reticle or wafer. Although these chucks do not have a pattern like a reticle, problems due to gas introduction and normal incidence still exist.

  The present invention relates to a cleaning apparatus and method for increasing the removal rate of fine particles, maintaining the throughput of an exposure apparatus, and reducing damage to a surface to be cleaned, and an exposure apparatus having the cleaning apparatus.

  An exposure apparatus according to one aspect of the present invention exposes a pattern of an original placed in a vacuum environment onto a substrate through a projection optical system and irradiates the original with a laser beam in a vacuum environment. In the exposure apparatus having a cleaning device for cleaning the substrate, the cleaning device has irradiation means for irradiating the laser beam at an angle in the range of 1 ° to 45 ° with respect to the surface on which the pattern of the original plate is formed. In the state where the irradiation means maintains the incident angle of the laser beam with respect to the surface on which the pattern is formed within the range, the laser beam is incident on a plurality of incident directions having different incident directions around the normal of the pattern surface. It is made to enter from a direction.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, it is possible to provide a cleaning apparatus and method that increase the removal rate of fine particles, maintain the throughput of the exposure apparatus, and reduce damage to the surface to be cleaned, and an exposure apparatus having the cleaning apparatus.

  Hereinafter, the EUV exposure apparatus 100 will be described with reference to FIG. Here, FIG. 1 is a schematic block diagram of the exposure apparatus 100. The exposure apparatus 100 is a projection exposure apparatus that exposes the pattern of the reticle 2 onto the wafer 1 using EUV light in a step-and-scan manner. The exposure apparatus 100 includes an illumination device (not shown), a reticle stage 3, a projection optical system 5, and a wafer stage 27 in a vacuum chamber (4a-4c). The exposure apparatus 100 further includes a cleaning device as will be described later.

  The EUV light has a wavelength of 5 nm to 20 nm (for example, a wavelength of 13.4 nm). Since EUV light has low transmittance to the atmosphere and generates contamination due to reaction with the remaining polymer organic gas, at least in the optical path through which EUV light passes (that is, the entire optical system) is a vacuum environment (10E− 5 to -7 Pa).

  The illumination device illuminates the reticle 2 with arcuate EUV light with respect to the arcuate field of view of the projection optical system 5, and has an EUV light source unit and an illumination optical system. The EUV light source unit uses a laser plasma light source or a discharge plasma light source. The illumination optical system includes a condenser mirror, an optical integrator, and an aperture.

  The reticle 2 is a reflective reticle, and is supported by the reticle stage 3 and driven in the scanning direction (first direction). The diffracted light emitted from the reticle 2 is reflected by the projection optical system 5 and projected onto the wafer 1. The reticle 2 and the wafer 1 are arranged in an optically conjugate relationship. Since the exposure apparatus 100 is a step-and-scan exposure apparatus, the reticle 2 and the wafer 1 are synchronously scanned to project a reticle pattern onto the wafer 1 in a reduced scale.

  The reticle stage 3 supports the reticle 2 via a reticle chuck (original chuck) 7 and is connected to a drive unit 84 described later. The reticle stage 3 is configured to be movable at least in the scanning direction (Y direction) by the drive unit 84. However, in another embodiment, it is configured to be further movable in other directions (X direction, rotation direction around the Z axis, etc.).

  The reticle chuck 7 is an electrostatic chuck for flattening, and attracts and holds the reticle 2 by electrostatic attraction force. The reticle chuck 7 is installed on the reticle stage 3 (provided integrally or supported). The reticle 2 is held by the reticle chuck 7 so that the pattern surface 2a on which the pattern is formed in the pattern region 30 is on the lower side or the projection optical system 5 side in FIG.

  The projection optical system 5 uses a plurality of multilayer mirrors to reduce and project an image of the reticle pattern onto the wafer 1 on the image plane. The number of the plurality of mirrors is about 4 to 6. In order to realize a wide exposure area with a small number of mirrors, the reticle 2 and the wafer 1 are simultaneously scanned using only a thin arc-shaped area (ring field) separated from the optical axis by a certain distance. Transcript.

  In another embodiment, the wafer 1 widely includes a liquid crystal substrate and other substrates (objects to be exposed). A photoresist is applied to the wafer 1. The wafer stage 27 supports the wafer 1 via a wafer chuck (substrate chuck) 6 and drives it in six axial directions. The wafer chuck 6 is an electrostatic chuck, and attracts and holds the wafer 1 by electrostatic attraction force.

  The xy positions of reticle stage 3 and wafer stage 27 are monitored by a laser interferometer (not shown). The scanning speed of the reticle stage 3 and the wafer stage 27 is synchronously controlled so that the relationship Vr / Vw = β is established. Here, the reduction magnification of the projection optical system 5 is 1 / β, the scanning speed of the reticle stage is Vr, and the scanning speed of the wafer stage 27 is Vw.

  The vacuum chamber (vacuum chamber) includes a reticle stage space 4a, a projection optical system space 4b, and a wafer stage space 4c. In the present application, the vacuum chamber may refer to one or more of these spaces.

The reticle stage space 4 a houses the reticle 2, reticle stage 3, and reticle chuck 7. In the reticle stage space 4a, an evacuation device 10a and a measurement device 70a are provided. The vacuum exhaust apparatus 10a can independently exhaust the reticle stage space 4a to a vacuum degree of 10 ⁻⁵ Pa to 10 ⁻⁷ Pa necessary for exposure. The measuring device 70a measures the degree of vacuum in the reticle stage space 4a. The range of the degree of vacuum measured by the measuring device 70a is in the range of 10 ⁻⁷ Pa to 100 Pa, and can be configured by combining a vacuum gauge and a pressure gauge. The reason why the measurement of 100 Pa is necessary is that it is used in the cleaning apparatus of this embodiment as will be described later. However, in another embodiment, it is sufficient that the measuring device 70a can measure at least 10 ⁻⁵ Pa to 10 ⁻⁷ Pa necessary for exposure. This is because the removal rate of the fine particles is high even if washing is performed within this range.

The projection optical system space 4b accommodates the projection optical system 5. In the projection optical system space 4b, an evacuation device 10b and a measurement device 70b are provided. In the projection optical system space 4b, an evacuation device 10b and a measurement device 70b are provided. The vacuum exhaust device 10b independently exhausts the projection optical system space 4b. The measuring device 70b measures the degree of vacuum in the projection optical system space 4b. The range of the degree of vacuum measured by the measuring device 70b may be the same as that of the measuring device 70a, but it is sufficient if at least 10 ⁻⁵ Pa to 10 ⁻⁷ Pa necessary for exposure can be measured.

The wafer stage space 4 c accommodates the wafer 1, the wafer chuck 6, and the wafer stage 27. The wafer stage space 4c is provided with an evacuation device 10c and a measurement device 70c. The vacuum exhaust device 10c independently exhausts the wafer stage space 4c. The measuring device 70c measures the degree of vacuum in the wafer stage space 4c. The range of the degree of vacuum measured by the measuring device 70a is in the range of 10 ⁻⁷ Pa to 100 Pa, and can be configured by combining a vacuum gauge and a pressure gauge. The reason why the measurement of 100 Pa is necessary is that it is used in the cleaning apparatus of this embodiment as will be described later. However, in another embodiment, the measuring device 70c only needs to measure at least 10 ⁻⁵ Pa to 10 ⁻⁷ Pa necessary for exposure. This is because the removal rate of the fine particles is high even if washing is performed within this range.

  The reticle stage space 4a and the projection optical system space 4b are partitioned by a gate valve 16a, and the projection optical system space 4b and the wafer stage space 4c are partitioned by a gate valve 16b.

  Reference numeral 15 denotes a wafer load lock chamber, and 8 denotes a transfer hand for loading and unloading the wafer 1 between the wafer load lock chamber 15 and the wafer stage space 4c. Reference numeral 10 e denotes an evacuation device for the wafer load lock chamber 15. 11a is a gate valve on the exposure apparatus 100 side provided in the wafer load lock chamber 15, and 11b is a gate valve on the wafer exchange chamber 14 side provided in the wafer load lock chamber 15. Reference numeral 14 denotes a wafer exchange chamber for temporarily storing the wafer 1 under atmospheric pressure, and reference numeral 13 denotes a transfer hand for loading and unloading the wafer 1 between the wafer exchange chamber 14 and the wafer load lock chamber 15.

  Reference numeral 26 denotes a reticle load lock chamber, and reference numeral 22 denotes a transfer hand for loading and unloading the reticle 2 between the reticle load lock chamber 26 and the reticle stage space 4a. Reference numeral 10 d denotes an evacuation device for the reticle load lock chamber 26. Reference numeral 12 a denotes an exposure apparatus 100 side gate valve provided in the reticle load lock chamber 26, and reference numeral 12 b denotes a reticle exchange chamber 19 side gate valve provided in the reticle load lock chamber 26. Reference numeral 19 denotes a reticle exchange chamber for temporarily storing the reticle under atmospheric pressure, and reference numeral 18 denotes a transfer hand for carrying in and out the reticle between the reticle exchange chamber 19 and the reticle load lock chamber 26.

  The cleaning device cleans the reticle 2 in the vacuum chamber (reticle stage space 4a) without introducing gas into the vacuum chamber (reticle stage space 4a). The cleaning apparatus includes an irradiation unit, a scanning unit, an attenuator 42 or a mirror 24, a changing unit (a part of the irradiation unit), measuring devices 70a to 70c, and a control unit 60. However, the measuring devices 70a to 70c and the control unit 60 can be diverted from those provided in the exposure apparatus 100. FIG. 2 is a partial enlarged cross-sectional view of the cleaning apparatus shown in FIG.

  The irradiating means irradiates the reticle 2 at an angle (within an angle range) of 1 ° to 45 ° with respect to the reticle 2 of the laser beam L for cleaning the reticle 2. The irradiation means includes a pulse laser 21, a beam shaping system (not shown), a laser beam introduction window 20, and an oblique incident illumination means.

  In the present invention, when the surface to be cleaned is irradiated with the laser beam, the incident angle of the laser, or the irradiation angle, is an angle formed by the laser beam and the surface to be cleaned (reticle pattern surface, pattern-formed surface). It is defined as The incident angle of the laser beam with respect to the pattern surface is 1 degree or more and 45 degrees or less, preferably 5 degrees (10 degrees) or more and 35 degrees (25 degrees) or less. Here, the angle between the normal of the pattern surface of the original and the incident laser beam may be referred to as an incident angle (incident angle). However, since the range of the incident angle in this case is opposite to the above range, it is in the range of 45 degrees to 89 degrees, more preferably 55 degrees (65 degrees) to 85 degrees (80 degrees).

  The incident direction of the laser beam is the direction in the rotation direction of the normal line of the surface to be cleaned (the direction around the normal line, the rotation direction around the normal line), that is, the laser when viewed from the normal direction of the reticle. Is defined as the direction of incidence. In other words, the direction of the incident light may be the direction of the optical path of the laser light when the optical path of the laser light is projected in the normal direction of the surface to be cleaned (reticle surface). Here, it is the most important point of the present embodiment that two laser beams having different incident directions are incident on the pattern simultaneously or at different timings. By configuring in this way, the pattern surface can be cleaned more cleanly. The first incident direction among the plurality of different incident directions at this time is parallel to the scanning direction (first direction) of the scanning exposure apparatus, and the second incident direction is the scanning direction. Desirably perpendicular to the direction. More specifically, the first incident direction among the plurality of different incident directions is parallel to the first plane including the normal of the pattern surface and the scanning direction. The second incident direction among the plurality of different incident directions is parallel to the second plane that includes the normal line of the pattern surface and is perpendicular to the first plane. Of course, in addition to this, a third incident direction and a fourth incident direction (rotation direction around the normal line) that are not parallel to the first and second incident directions are provided, and laser light can be incident from each direction. good.

  As the pulse laser 21, ArF laser (wavelength 193 nm), KrF laser (wavelength 248 nm), YAG laser (wavelength 266 nm, etc.), femtosecond laser (wavelength 266 nm, etc.), etc. can be used. . However, the present invention does not prevent the use of EUV light as exposure light.

  The beam shaping system shapes the beam shape of the laser light L.

  The laser beam introduction window 20 is provided in a partition wall of the vacuum chamber (reticle stage space 4a) and is made of a light transmitting material that has little absorption with respect to an incident wavelength, such as glass or quartz that transmits the laser beam L.

  The oblique incidence illumination means is a means for guiding the laser light L to the reticle 2 at an incident angle in the range of 1 ° to 45 °. That is, the incident angle θ of the laser beam L with respect to the pattern surface 2a of the reticle 2 satisfies 1 ° ≦ θ ≦ 45 °.

  The oblique incidence illumination means may be configured by setting the optical axis of the pulse laser 21 within the above range with respect to the pattern surface 2 a of the reticle 2.

  However, in this embodiment, the optical axis of the laser beam L emitted from the pulse laser 21 is set parallel to the pattern surface 2a of the reticle 2, and the angle of deflection for deflecting the laser beam L that has passed through the laser beam introduction window 20 is variable. A bending mirror 23 is provided. The folding mirror 23 extends in the X direction orthogonal to the paper surface of FIG. 1 and has a reflection region sufficient to cover the length of the pattern surface 2a of the reticle 2 in the X direction of FIG. The bending mirror 23 deflects the laser light L from the lower side of FIG. The bending mirror 23 is driven in the six-axis direction by the driving unit 82, and the inclination angle around the X axis can be controlled by the control unit 60 that controls the driving unit 82.

  The scanning unit scans the laser beam L over the entire pattern surface 2 a of the reticle 2. The scanning unit may be configured to scan the laser beam L as a line extending in the X direction and scan one-dimensionally in the Y direction, or may scan a spot of the laser beam L on the pattern surface 2a two-dimensionally. Good.

  The scanning means of this embodiment has an X direction scanning means for scanning in the X direction and a Y direction scanning means.

  The X direction scanning unit includes a polygon mirror 40 and an fθ lens 41. The polygon mirror 40 scans the laser light L emitted from the pulse laser 21 in the X direction, and the polygon mirror 40 is rotationally driven by the drive unit 80 on the XY plane. Note that a galvanometer mirror may be used instead of the polygon mirror 40. The fθ lens 41 has an image height Y proportional to the incident angle θ, and when the focal length is f, Y = fθ. In particular, in the present invention, since the irradiation angle of the laser with respect to the reticle needs to be constant, the laser light emitted from the fθ lens 41 is a telecentric fθ lens that maintains parallel light even if the incident angle θ changes. desirable.

  The Y direction scanning unit has a reticle stage 3 that moves in the Y direction (scanning direction). As described above, reticle stage 3 is driven in the six-axis direction by drive unit 84.

  Unlike the present embodiment, a scanning mechanism in which the pulse laser 21 scans the reticle pattern surface 2a two-dimensionally with the laser beam L may be provided.

  The attenuator 42 is a laser light output attenuator that attenuates the laser light L reflected by the reticle 2. Thereby, it is possible to prevent the laser light L reflected by the reticle 2 from being irradiated to other members of the exposure apparatus 100. In this embodiment, the incident part of the laser light L of the attenuator 42 is covered with a glass window so that the fine particles generated in the attenuator 42 are not scattered. Further, although the attenuator 42 of the present embodiment is provided in the vacuum chamber (reticle stage space 4a), the attenuator 42 may be provided outside the vacuum chamber (reticle stage space 4a). In this case, the laser light L is led out of the vacuum chamber through a transmission window (not shown) and attenuated there.

  The folding mirror 24 may be inserted instead of the attenuator 42. In this case, the folding mirror 24 is connected to a driving unit (not shown) so as to be driven, and the driving unit is controlled by the control unit 60.

FIG. 3 is a schematic cross-sectional view showing a modification of FIG. In FIG. 3, the solid line indicates the laser beam L ₁ introduced from the pulse laser 21 into the vacuum chamber (reticle stage space 4 a), reflected by the pattern surface 2 a of the reticle 2, and reaching the folding mirror 24. Dashed lines, is reflected by the folding mirror 24, again, it illustrates the laser beam L ₂ incident on the pattern surface 2a of the reticle 2.

FIG. 4 is a schematic cross-sectional view of the vicinity of one fine particle P adhering to the pattern surface 2 a of the reticle 2. Incident angle .theta.1 of the laser beam L ₁ is satisfied 1 ° ≦ θ1 ≦ 45 °, the incident angle .theta.2 of the laser beam L ₂ is to adjust the angle of the mirror 24 so as to satisfy the 1 ° ≦ θ2 ≦ 45 ° . In this way, the folding mirror (reflection mirror) 24 returns the laser light L reflected at the irradiation position of the reticle 2 to the irradiation surface and the pattern surface in the vicinity thereof. At this time, the returned laser light is incident so as to form an angle (absolute value) of 1 ° to 45 ° with respect to the pattern surface. At this time, the folding mirror (reflection mirror) 24 desirably returns the laser light to the original irradiation position. However, the present invention is not limited to this, and the laser light may be returned to a position slightly different from the irradiation position.

Referring to FIG. 5, the timing of the laser light L ₁ and L ₂ is irradiated to the pattern surface 2a of the reticle 2 will be described. Here, FIG. 5 is a graph for explaining the timing of the laser beam L ₁ and L _2. In FIG. 5, the horizontal axis represents time, and the vertical axis represents the irradiation intensity of laser light. The solid line represents the profile of the laser beam L ₁ that is first irradiated on the pattern surface 2a of the reticle 2, the broken line represents the profile of the laser beam L ₂ to be re-irradiated to the reticle 2 is reflected by the folding mirror 24 Yes.

When the pulse laser 21 uses a Q-switched YAG laser, the pulse time width Δτ is about 7 ns. The irradiation intensity of the laser beam L ₂ is weak due to absorption of the reticle 2 and the surface of the mirror 24. However, the pulse time width Δτ remains constant. The timing difference Δτ ′ between the laser beams L ₁ and L ₂ is about 3 ns, assuming that the optical path length difference is 1 m.

The folding mirror 24 can irradiate the fine particles P adhering to the pattern surface 2a with laser light having a time difference of ns order from two directions different by 180 °. For this reason, even with the laser light L ₁ alone, even particles that could not be completely removed can be removed with the laser light L _2, so that the removal rate is improved.

  The changing means is a laser in a state where the incident angle of the laser beam L with respect to the pattern surface 2a of the reticle 2 is maintained within the range of 1 ° or more and 45 ° or less (in this embodiment, the incident angle is kept the same). The incident direction of the light L is changed. The changing means can employ various configurations as will be described below.

  In one embodiment, the changing means is constituted by a reticle stage 3 that can rotate the reticle 2 in a plane. 6 is a top view showing a state in which the reticle stage 3 is in the initial position, and a lower view in FIG. 6 is a top view showing a state in which the reticle stage 3 is rotated by 90 ° from the position shown in the upper view of FIG. is there. As described above, the reticle stage 3 is configured to be driven in the Y-axis and rotation axis directions by the drive unit 84, and the control unit 60 controls the rotation of the reticle stage 3 by the drive unit 84.

  In another embodiment, the changing means includes a robot hand 22 that takes out the reticle 2 from the reticle stage 3 and mounts it on the reticle stage 3 in different postures, as shown in FIG. Here, FIG. 7 is a top view showing the robot hand 22. The robot hand 22 of this embodiment is mounted on the reticle chuck 7 in a posture in which the reticle 2 is rotated by 90 °. In FIG. 7, 46 is a reticle changer for exchanging the reticle 2 in the reticle stage space 4a, and 47 is a reticle rotating stage.

  The reticle rotation stage 47 is configured to be capable of rotating by 90 ° on the XY plane as indicated by the arrow in FIG. The robot hand 22 includes a grip portion 22a, arm portions 22b and 22c, and a base portion 22d of the reticle 2. In the robot hand 22, the expansion and contraction of the arm portions 22 b and 22 c and the rotation around the base portion 22 d of the arm portions 22 b and 22 c are driven by the driving unit 90, and the driving is controlled by the control unit 60.

  Using the robot hand 22, the reticle 2 removed from the reticle stage 3 can be placed on the reticle rotation stage 47 and rotated by an arbitrary angle (90 ° in this embodiment). The robot hand 22 is configured such that the reticle 2 can be conveyed between these four units, that is, the reticle load lock chamber 26, the reticle changer 46, the reticle stage 3, and the reticle rotation stage 47. According to the present embodiment, the reticle stage 3 has the advantage that it is not necessary to provide a rotation axis of θ, and the configuration of the reticle stage 3 can be simplified.

  In yet another embodiment, the changing means is configured to be inserted into and removed from the optical path of the laser beam L, and includes a routing optical system including a deflection element that deflects the laser beam. Reference numeral 45 in FIG. 8 denotes a mirror (which may be replaced with an optical element that bends the optical path, such as a deflecting element, a prism, or a diffraction grating). Here, FIG. 8 is a schematic top view of the changing means having the switching mirror (deflection element) 45. The switching mirror (deflection element) 45 is configured to be inserted into and withdrawn from the optical path of the laser light L emitted from the pulse laser 21 by the driving unit 86. The driving by the driving unit 86 is controlled by the control unit 60.

  Note that the switching mirror 45 may be a beam splitter or a half mirror. In this case, the laser beam is divided into a plurality of laser beams (partial laser beams) by the beam splitter and the half mirror, and each is incident on the reticle from different incident directions. Preferably, the partial laser light is incident on the reticle from a plurality of incident directions including an incident direction parallel to the direction in which the reticle is driven (scanning direction) and an incident direction perpendicular thereto. Of course, in this case, there is no need to switch the optical path in terms of time. While the reticle stage 3 is fixed, the entire surface of the reticle can be laser-scanned from different directions. This can be achieved by simultaneously using the scanning optical systems 40a and 41a, the driving unit 80a, the scanning optical systems 40b and 41b, and the driving unit 80b.

  In FIG. 8, the oblique incident illuminating means before the incident direction is changed is composed of the folding mirror 23a, and the oblique incident illuminating means after the incident direction is changed is composed of the folding mirror 23b. In this case, the bending mirrors 23a and 23b are driven by the drive units 82a and 82b, respectively. The scanning means before the incident direction is changed is composed of a polygon mirror 40a and an fθ lens 41a, and the scanning means after the incident direction is changed is composed of a polygon mirror 40b and an fθ lens 41b.

  In still another embodiment, as shown in FIG. 9, the optical system includes a routing optical system including a beam splitter 48 that splits the laser light L. Here, FIG. 9 is a schematic top view having the beam splitter 48. In this case, the changing means is not necessary, and the laser beam L is irradiated simultaneously from different orthogonal directions. The oblique incidence illumination means becomes the bending mirrors 23a and 23b, and is simultaneously driven by the drive units 82a and 82b. As a means for scanning the entire surface of the reticle, a biaxial movement mechanism in the X and Y directions of the reticle stage 3 or a cleaning stage 28 described later is used.

  The control unit 60 acquires various types of information including the open / closed states of the gate valves 11a, 11b, 12a, 12b, 16a, and 16b, the measurement results of the measuring apparatuses 70a to 70c, and the operating state of the exposure apparatus 100. Based on such information, the control unit 60 controls (allows) the evacuation by the vacuum evacuation devices 10a to 10e, the irradiation by the pulse laser 21, and the driving by the driving units 80 to 90. Although “drive units 80 to 90” are used, it goes without saying that the drive unit corresponding to the changing means is selected.

  Hereinafter, the operation of the exposure apparatus 100 will be described with reference to FIGS. Here, FIG. 10 is a flowchart for explaining the operation of the exposure apparatus 100.

  First, as a pre-exposure process, the pattern surface 2a of the reticle 2 is cleaned (step 1100), the reticle chuck 7 is cleaned (step 1200), and the wafer chuck 6 is cleaned (step 1300). Thereafter, exposure is performed (step 1400). Further, the control unit 60 determines whether or not maintenance is necessary, for example, based on whether or not the exposure of a predetermined number of wafers 1 has been completed (step 1500). When it is determined that maintenance is necessary, the control unit 60 returns to Step 1100, and when it is determined that maintenance is not necessary, the control unit 60 continues Step 1400.

Hereinafter, the details of step 1100 will be described with reference to FIG. Here, FIG. 11 is a flowchart for explaining details of step 1100 shown in FIG. First, the control unit 60 acquires the measurement result of the vacuum chamber (space 4a to 4c) by the measuring device 70a, and determines whether or not the degree of vacuum of the reticle stage space 4a is 100 Pa or less (step 1104). Usually, the reticle stage space 4a (or the space for cleaning the reticle) is a pressure region of 10 ⁻⁵ Pa to 10 ⁻⁷ Pa, and desirably 100 Pa or less at the highest. If the air pressure in the space for cleaning the reticle (or a reticle stage space is acceptable) is higher than 100 Pa, it is determined that the apparatus is abnormal. In that case, the cleaning operation is forcibly terminated (step 1102). In this embodiment, when the reticle is cleaned, it is assumed that the reticle is placed in a vacuum environment (atmospheric pressure 100 Pa or less). Of course, it is desirable that the reticle be in a vacuum environment (100 Pa or less) even when exposed. Similarly, a substrate such as a wafer (exposed body, substrate to be exposed) is preferably placed in a vacuum environment (100 Pa or less). If the substrate is not placed in a vacuum environment, an exposure apparatus is used. Means for stopping may be provided. When the controller 60 determines that the degree of vacuum of the reticle stage space 4a is 100 Pa or less (step 1104), the control unit 60 transports the reticle 2 to the reticle stage space 4a and mounts it on the reticle stage 3 via the reticle chuck 7. (Step 1106).

  Next, the control unit 60 starts the irradiation of the laser beam L by the pulse laser 21 (step 1108). Further, the control unit 60 drives the reticle stage 3 through the drive unit 80 (or 80a) and the polygon mirror 40 (or 40a) and the drive unit 84, and the pattern surface 2a of the reticle 2 is moved by the laser light L. Scan (step 1110).

  In scanning, the polygon mirror 40 is rotated on the XY plane to deflect the laser light L in the X direction, and the reticle stage 3 is moved in the Y direction at a constant speed. Thereby, the entire pattern surface 2a of the reticle 2 can be cleaned. FIG. 14 is a schematic plan view showing this state. A pattern region 30 of the reticle 2 is a region to be cleaned. Reference numeral 50 denotes an irradiation region of the laser beam L, and in this embodiment, has a square shape with one side W. Scanning is started from the irradiation region 50, one scanning is completed at 51, the next scanning is started, and this is repeated. In this embodiment, the movement of the reticle stage 3 and the scanning of the laser beam L are performed in synchronization, and the reticle 2 always moves at a constant speed, but may move stepwise for each scanning. For example, the settings disclosed in Patent Document 3 can be used for the scanning speed of the laser beam L, the irradiation region 50, the oscillation frequency, the number of irradiation pulses necessary for cleaning, and the like.

  The present inventors have experimented that when removing the fine particles P adhering to the surface to be cleaned with the laser light L, it is possible to efficiently remove the fine particles P when the laser light L is obliquely incident rather than perpendicularly incident on the surface to be cleaned. Discovered. FIG. 15A is a schematic cross-sectional view showing a state where the laser light L is perpendicularly incident on the fine particles P on the pattern surface 2a of the reticle 2 which is the surface to be cleaned. FIG. 15B is a schematic cross-sectional view showing a state in which the laser light L is perpendicularly incident on the fine particles P on the pattern surface 2 a of the reticle 2.

  Although the mechanism of particle removal by the laser beam L is not clear, (1) instantaneous thermal expansion between the particle P and the substrate to be cleaned during pulse irradiation, (2) light pressure action, and (3) photochemical It is expected to be a combination of action. In particular, in the case of the inorganic fine particles P, the influence of the factors (1) and (2) is large.

  Accordingly, in the case of vertically incident light, due to thermal expansion, a force acts in the direction in which the fine particles P separate from the surface to be cleaned, but at the same time, a force acts in a direction in which the fine particles P are pressed against the surface to be cleaned. Therefore, the separation force of the fine particles P does not act 100% effectively.

  On the other hand, in the case of obliquely incident light, the direct light incident on the fine particle P and the reflected light that reflects the surface to be cleaned are combined to irradiate the fine particle P with the laser light L. Accordingly, the force with which the fine particles P are separated from the surface to be cleaned due to thermal expansion is larger than that at the time of normal incidence. Moreover, the light pressure in that case is not a direction in which the fine particles P are pressed against the surface to be cleaned, but a force in the tangential direction acts largely. With the above mechanism, the removal rate of the fine particles P is higher in the oblique incident light.

  As a result of experiments, the inventors of the present invention have improved the removal rate as the laser incident angle is gradually decreased from the state of normal incidence (θ = 90 °) with respect to the surface. It has been found that the removal rate is particularly effectively improved by the following. Therefore, in this embodiment, the incident angle θ of the laser beam is set in a range of 1 ° to 45 °.

  Further, the energy E applied to the surface to be cleaned of obliquely incident light has a relationship of E = E0 / sin θ with respect to the energy E0 of vertically incident light. As θ decreases, the energy per unit area reaching the surface to be cleaned decreases, so that the surface to be cleaned is less damaged. Thus, by making the incident angle of the laser light L smaller than the vertical incidence (θ = 90 °), the removal rate of the fine particles P can be improved without damaging the surface to be cleaned.

  Next, the inventors experimentally show that when removing the fine particles P from the surface to be cleaned with laser light, it is more efficient to remove the fine particles P in a vacuum environment than to remove the fine particles P in an atmospheric pressure environment. discovered.

  In the atmospheric pressure, even if the fine particles P are once separated from the surface to be cleaned by laser light, the kinetic energy is lost instantly due to the fluid resistance of the gas molecules, and van der Waals force or static electricity is charged if the fine particles P are charged. Reattaches by force.

  On the other hand, in a vacuum environment, the behavior of the fine particles P becomes discontinuous collisions with gas molecules. Therefore, when the fine particles P are separated from the surface to be cleaned, the fluid resistance does not act, and thus the fine particles P are released to the open space and removed. It is considered that the removal rate of the fine particles P in vacuum is improved by the action of such a mechanism.

  The present inventors estimated the acceleration at which particles adhering to the van der Waals force are detached from the surface to be cleaned by laser light irradiation. FIG. 16 shows the result of calculation of the distance to be separated from the surface to be cleaned and reach. In FIG. 16, the horizontal axis is the pressure [Pa], and the vertical axis is the normalized distance.

  As described above, when the degree of vacuum is higher than 100 Pa, the separation distance of the fine particles P is 0, that is, the fine particles P are immediately reattached even if they are detached. However, when the degree of vacuum is 100 Pa or less, the separation distance gradually increases. When the degree of vacuum is about 10 Pa, the separation distance completely leaves the surface to be illuminated and is removed without reattachment. For this reason, in this embodiment, in order to effectively remove the fine particles P without reattachment, the environment of the surface to be cleaned is set to a vacuum degree of 100 Pa or less, preferably 10 Pa or less.

Since the pattern surface 2a on which the line and space pattern is formed has the concave portion 2b and the convex portion 2c, it is necessary to consider the position where the fine particles P are present when the pattern surface 2a is illuminated obliquely. FIG. 17 is an enlarged cross-sectional view in the case where fine particles P exist in each of the concave portion 2b and the convex portion 2c of the pattern surface 2a having a line and space pattern. In the figure, the pattern present on the surface (bottom) of the recess 2b and fine particles P _1, are distinguished pattern present on the surface (top) of the projecting portions 2c as fine particles P _2.

The laser light L having an incident angle of 1 ° or more and 45 ° or less reaches the fine particle P ₂ and can be easily removed regardless of the incident direction. However, for particles P _1, may laser beam L by the incident direction of the aspect ratio and the laser beam L of the pattern is not reached, in this case, can not be removed particulates P _1.

FIG. 18 is a schematic plan view showing four typical line and space patterns LS1 to LS4. Usually, the pattern of the pattern surface 2a is composed of a combination of a line and space pattern LS1 extending in the Y direction and a line and space pattern LS2 extending in the X direction. It may reach the particles P ₁ at the bottom of the line-and-space pattern LS1 without the laser beam L, combined the incident direction of the laser beam L is blocked in the Y direction. Further, it is possible to reach the particulate P ₁ on the bottom of the line-and-space pattern LS2 without laser beam L, combined the incident direction of the laser beam L in the X direction is blocked. For this reason, in this embodiment, the fine particles P ₁ and P ₂ are efficiently removed from the pattern surface 2 a having LS 1 and LS 2 by scanning the laser light L in two orthogonal directions (XY directions).

  However, the present invention provides a line and space pattern LS3 in which the pattern surface 2a extends at an angle of 45 ° with respect to the X axis and a line and space pattern LS4 that extends at an angle of 45 ° with respect to the Y axis. Is also applicable. In this case, the laser beam L may be scanned in the direction in which these patterns extend.

  Further, the scanning direction is not limited to the orthogonal direction. For example, if there is only one direction in which the pattern extends, only that direction needs to be scanned. For example, if the pattern surface 2a has only LS1, only the Y direction needs to be scanned. If the pattern surface 2a has only LS1 and LS3, only the direction of 45 ° with respect to the Y direction and the X axis needs to be scanned.

Hereinafter, the case where the laser beam L is scanned in the XY directions will be described. 6 is a schematic plan view of the reticle pattern surface 2a on which the reticle 2 is mounted on the reticle stage 3. FIG. First, the control unit 60 controls the pulse laser 21 to irradiate the pattern region 30 of the pattern surface 2 a of the reticle 2 with the laser light L from the −Y direction. The control unit 60 controls the driving unit 80 to scan the laser light L in the X direction with the polygon mirror 40. In synchronization with this, the control unit 60 controls the drive unit 84 to move the reticle stage 3 in the Y direction, and scans the entire pattern region 30. Thus, to remove the particulates _{P 1} and _{P 2} from the line and space pattern LS1. Fine particles P ₂ attached to the other patterns can also be removed at this time.

When the control unit 60 determines that the scanning is completed (step 1112), the control unit 60 adjusts the incident direction by the changing unit (step 1114). In FIG. 6, the changing means is the reticle stage 3 that can be rotated by 90 °, so that the control unit 60 drives the reticle stage 3 from the upper state of FIG. Rotate. Thereafter, scanning is similarly started. When the control unit 60 determines that the scanning is finished, the cleaning of the reticle 2 is finished (step 1116). Thus, it is possible to remove the fine particles P ₁ from the line and space pattern LS2.

  In step 1114, the change means shown in FIG. That is, the control unit 60 controls the driving unit 90 to take out the reticle 2 from the reticle stage 3 with the robot hand 22 and mount it on the reticle rotation stage 47. Thereafter, the control unit 60 controls the drive unit 88 to rotate the reticle rotation stage 47 by 90 °. Next, the control unit 60 controls the drive unit 90 to take out the reticle 2 from the reticle rotation stage 47 with the robot hand 22 and mount it on the reticle stage 3. In this case, the reticle stage 3 may be configured to be movable only in the Y direction.

In the case of the changing means shown in FIG. That is, the control unit 60 first retracts the deflecting mirror 45 from the optical path of the laser light L as shown in the upper diagram of FIG. Then, the control unit 60 controls the pulse laser 21 to irradiate the pattern region 30 of the pattern surface 2 a of the reticle 2 with the laser light L from the −Y direction. The control unit 60 controls the driving unit 80a to scan the laser light L in the X direction with the polygon mirror 40a. In synchronization with this, the control unit 60 controls the drive unit 84 to move the reticle stage 3 in the Y direction, and scans the entire pattern region 30. Thus, it is possible to remove the fine particles _{P 1} and _{P 2} from the line and space pattern LS1. Fine particles P ₂ attached to the other patterns can also be removed at this time.

Next, when the control unit 60 determines that the scanning is completed (step 1112), the control unit 60 controls the drive unit 86 to insert the deflection mirror 45 into the optical path of the laser beam L as shown in the lower diagram of FIG. Thereby, the incident direction of the laser beam L can be adjusted (step 1114). Thereafter, as shown in the lower diagram of FIG. 8, the control unit 60 controls the pulse laser 21 to irradiate the pattern region 30 of the pattern surface 2 a of the reticle 2 with the laser light L from the + X direction. Further, the control unit 60 controls the driving unit 80b to scan the laser light L in the Y direction with the polygon mirror 40b. In synchronization with this, the control unit 60 controls the drive unit 84 to move the reticle stage 3 in the X direction, thereby scanning the entire surface of the pattern region 30. When the control unit 60 determines that the scanning is finished, the cleaning of the reticle 2 is finished (step 1116). Thus, it is possible to remove the fine particles P ₁ from the line and space pattern LS2.

In the case of the changing means shown in FIG. That is, the control unit 60 controls the pulse laser 21 to irradiate the pattern region 30 of the pattern surface 2 a of the reticle 2 with the laser light L from the −Y direction and the + X direction. In this case, it becomes possible to simultaneously irradiate the irradiation region 50 with the laser beam L divided into two. Since the laser beam L is irradiated simultaneously from a plurality of incident directions, step 1114 for changing the incident direction of the laser beam is not necessary. The entire pattern area 30 of the reticle 2 can be cleaned by using the biaxial movement function of the reticle stage 3 or the cleaning stage 28 described later. By making it possible to irradiate laser light simultaneously from different directions in this way, it is possible to remove even if the fine particles P ₁ are attached to the bottom of the line and space pattern extending in the laser light incident direction.

  Returning again to FIG. 10, next, the reticle chuck 7 is cleaned (step 1200). FIG. 12 is a flowchart for explaining details of step 1200 shown in FIG. Since the reticle chuck 7 does not have a pattern, it is not necessary to change the incident direction of the laser beam L in the cleaning. The rest is the same as the cleaning of the reticle 2.

That is, the control unit 60 acquires the measurement result of the measurement apparatus 70a, and determines whether or not the degree of vacuum of the reticle stage space 4a is 100 Pa or less (step 1204). The normal reticle stage space 4a is a pressure region of 10 ⁻⁵ Pa to 10 ⁻⁷ Pa, and if it is 100 Pa or more, it is determined that the apparatus is abnormal and the cleaning operation is forcibly terminated (step 1202). When the controller 60 determines that the degree of vacuum of the reticle stage space 4a is 100 Pa or less (step 1204), the controller 60 starts irradiating the laser beam L with the pulse laser 21 (step 1206). Further, the control unit 60 drives the reticle stage 3 via the driving unit 80 and the polygon mirror 40 and the driving unit 84, and scans the reticle chuck 7 with the laser beam L (step 1208). If the control unit 60 determines that the scanning has ended, the control unit 60 ends the processing (step 1210).

  Returning again to FIG. 10, next, the wafer chuck 6 is cleaned (step 1300). FIG. 13 is a flowchart for explaining details of step 1300 shown in FIG. Since the wafer chuck 6 does not have a pattern, it is not necessary to change the incident direction of the laser beam L in the cleaning. The rest is the same as the cleaning of the reticle 2.

That is, the control unit 60 acquires the measurement result of the measurement apparatus 70c, and determines whether or not the degree of vacuum of the wafer stage space 4c is 100 Pa or less (step 1304). Normally, the wafer stage space 4c is a pressure region of 10 ⁻⁵ Pa to 10 ⁻⁷ Pa, and if it is 100 Pa or more, the apparatus is abnormal and the cleaning operation is forcibly terminated (step 1302).

  When the controller 60 determines that the degree of vacuum of the wafer stage space 4c is 100 Pa or less (step 1304), the controller 60 starts the irradiation of the laser beam L with the pulse laser 21 (step 1306). Further, the control unit 60 drives the reticle stage 3 through the driving unit 80 and the polygon mirror 40 and the driving unit 84, and scans the wafer chuck 6 with the laser beam L (step 1308). If the control unit 60 determines that the scanning has ended, the control unit 60 ends the processing (step 1310).

  FIG. 19 is a schematic sectional view showing the arrangement of the exposure apparatus 100 when cleaning the reticle chuck 7 and the wafer chuck 6. In FIG. 19, the same members as those in FIG.

  In FIG. 19, laser light is applied to each chuck 7 and 6 at an incident angle of 1 ° to 45 °. Reference numeral 20 denotes a laser introduction window, and 23 denotes a bending mirror. Each of those used for cleaning the reticle 2 can be diverted. Similarly, 20a is a laser window, 23a is a deflection mirror, and each is used for cleaning the wafer chuck 6.

  The chucks 7 and 6 have a problem that the fine particles P are caught. For this reason, the chuck surface usually has a pin shape in order to reduce the contact area. When the fine particles P adhere to the tip of the pin, the fine particles P are sandwiched between the reticle 2 or the wafer 1. When the fine particles P adhere to the reticle chuck 7, the object surface is tilted. If the fine particles P adhere to the wafer chuck 6, the depth of focus of the optical system is affected. However, it is not necessary to change the incident direction of the laser beam L because there is no problem even if the fine particles P adhere to the bottom. Japanese Patent Application No. 2006-331585 can also be applied to other components and sequences when performing chuck cleaning.

  FIG. 20 is a schematic cross-sectional view showing the configuration of exposure apparatus 100 that cleans reticle 2 on stage 28 that is different from reticle stage 3. In FIG. 20, the same members as those in FIG. In FIG. 20, the transfer system such as the reticle load lock chamber 26 and the wafer load lock chamber 15 is omitted. The stage 28 is a stage dedicated to cleaning different from the reticle stage 3. The reticle 2 is cleaned on the stage 28. The changing means in this case is the same except that the reticle stage 3 is replaced with the stage 28 in FIGS.

  Although the above-described embodiment has shown the case where laser cleaning is performed on an object to be cleaned in the EUV exposure apparatus 100, the present invention may not be cleaned in the EUV exposure apparatus. For example, a unit completely independent of the EUV exposure apparatus may be used as the cleaning apparatus.

  Next, an example of a device manufacturing method using the exposure apparatus 100 will be described with reference to FIGS. FIG. 21 is a flowchart for explaining how to fabricate semiconductor devices (ie, semiconductor chips such as IC and LSI, or liquid crystal panels, CCDs, etc.). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (reticle fabrication), the reticle 2 on which the designed circuit pattern is formed is fabricated. On the other hand, in step 3 (wafer manufacture), the wafer 1 is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer 1 by lithography using the reticle 2 and the wafer 1. The next step 5 (assembly) is referred to as a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like. including. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 22 is a detailed flowchart of the wafer process in Step 4 of FIG. In step 11 (oxidation), the surface of the wafer 1 is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer 1 by vapor deposition or the like. In step 14 (ion implantation), ions are implanted into the wafer 1. In step 15 (resist process), a photosensitive material is applied to the wafer 1. Step 16 (exposure) uses the exposure apparatus 100 to expose a reticle pattern onto the wafer 1. In step 17 (development), the exposed wafer 1 is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer 1. If the manufacturing method of this embodiment is used, transfer defects are reduced by the cleaning device, so that a higher quality device (semiconductor element, LCD element, imaging element (CCD, etc.), thin film magnetic head, etc.) than the conventional one is manufactured. Can do. In addition, a device manufacturing method using the exposure apparatus 100 and a device as a result (intermediate, final product) also constitute one aspect of the present invention.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

It is a schematic block diagram of the exposure apparatus of one Example of this invention. 2 is a partial enlarged cross-sectional view of a cleaning device of the exposure apparatus shown in FIG. It is a partial expanded sectional view of the modification of the washing | cleaning apparatus shown in FIG. FIG. 4 is a partial enlarged cross-sectional view of a pattern surface of the reticle shown in FIG. 3. It is a graph for demonstrating the effect of the washing | cleaning apparatus shown in FIG. It is a schematic block diagram of one Example of the change means applicable to the washing | cleaning apparatus shown in FIG. It is a schematic block diagram of the modification of the change means shown in FIG. It is a schematic block diagram of another modification of the change means shown in FIG. It is a schematic block diagram of another modification of the change means shown in FIG. 2 is a flowchart for explaining the operation of the exposure apparatus shown in FIG. It is a flowchart for demonstrating the detail of step 1100 shown in FIG. It is a flowchart for demonstrating the detail of step 1200 shown in FIG. It is a flowchart for demonstrating the detail of step 1300 shown in FIG. It is a schematic plan view for demonstrating the scanning step 1110 shown in FIG. FIGS. 15A and 15B are schematic cross-sectional views for explaining the fine particle removal effect of normal incidence light and oblique incidence light, respectively. It is a graph for demonstrating the effect of removal of a vacuum degree and microparticles | fine-particles. It is a schematic sectional drawing for demonstrating the problem at the time of removing the microparticles | fine-particles formed in the pattern surface by the oblique incident light. FIG. 2 is a schematic plan view showing various line and space patterns that can be formed on the pattern surface of the reticle shown in FIG. 1. It is a schematic block diagram of the modification of the exposure apparatus shown in FIG. It is a schematic block diagram which shows the exposure apparatus of step 1200 and 1300 shown in FIG. It is a flowchart for demonstrating the device manufacturing method using the exposure apparatus shown in FIG. It is a detailed flowchart of step 4 shown in FIG.

Explanation of symbols

1 Wafer (substrate)
2 Reticle (original)
3 Reticle stage 6 Wafer chuck 7 Reticle chuck 27 Wafer stage 23-23b Incident angle variable mirror 24 Beam folding mirror 42 Beam attenuator 20 Pulse laser light source 40-40b Laser scanning unit 41-41b fθ lens 60 Control unit 70a-70c Measuring device 100 exposure equipment

Claims (12)

In an exposure apparatus having a cleaning apparatus that exposes a substrate pattern through a projection optical system to the substrate disposed in a vacuum environment and cleans the original plate by irradiating the original plate with laser light in a vacuum environment.
The cleaning apparatus has irradiation means for irradiating the laser beam at an angle in a range of 1 ° to 45 ° with respect to the surface on which the pattern of the original plate is formed,
In the state where the irradiation means maintains the incident angle of the laser beam with respect to the surface on which the pattern is formed within the range, a plurality of incident directions in which the incident directions around the normal line of the pattern surface are different from each other. An exposure apparatus characterized in that the light is incident on the exposure apparatus. The exposure apparatus exposes the pattern of the original on the substrate while driving the original in the first direction,
Of the plurality of different incident directions, a first incident direction is parallel to the first direction,
2. The exposure apparatus according to claim 1, wherein a second incident direction different from the first incident direction among the plurality of different incident directions is perpendicular to the first direction.   3. An exposure apparatus according to claim 1, wherein an atmospheric pressure for cleaning the original plate is 100 Pa or less. The irradiation means has a robot hand that supports the original plate and can rotate the original plate in a plane, or a robot hand that takes out the original plate from a stage that supports the original plate and mounts the original plate on the stage in different postures,
4. The exposure apparatus according to claim 1, wherein the irradiation unit switches the incident direction by rotating the original plate in a rotation direction with respect to a normal line of a pattern surface of the original plate. 5. . The irradiating means has a deflecting element configured to be inserted into and removed from the optical path of the laser beam,
The exposure according to any one of claims 1 to 3, wherein an incident direction of the laser light with respect to the pattern surface is switched by switching insertion / removal of the deflection element into / from an optical path of the laser light. apparatus. The irradiation means has a beam splitter that divides the laser beam,
4. The exposure apparatus according to claim 1, wherein a plurality of partial laser beams divided by the beam splitter are incident on the pattern surface from different incident directions.   The exposure apparatus according to claim 1, wherein the cleaning apparatus further includes an attenuator that attenuates the laser light reflected by the original.   A reflection mirror that reflects the laser light reflected at the irradiation position of the pattern surface and makes the incident light incident on the pattern surface so as to form an angle of 1 ° to 45 ° with respect to the pattern surface; 8. The exposure apparatus according to claim 1, further comprising: an exposure apparatus. In an exposure apparatus that exposes a substrate pattern to a substrate through a projection optical system in a vacuum environment, and in a cleaning apparatus that cleans the original plate in a vacuum environment,
Irradiating means for irradiating laser light for cleaning the original plate at an angle in the range of 1 ° to 45 ° with respect to the surface on which the pattern of the original plate is formed;
The irradiating means causes the laser light to be incident from a plurality of incident directions having different incident directions around a normal line of the pattern surface while maintaining an incident angle of the laser light with respect to the pattern within the range. Characteristic cleaning device. In an exposure apparatus that exposes a substrate pattern under a vacuum environment onto a substrate via a projection optical system, in the cleaning method for cleaning the original plate in a vacuum environment,
Determining whether the degree of vacuum of the space in which the original plate is arranged is 100 Pa or less;
When the determination step determines that the degree of vacuum is 100 Pa or less, a laser beam for cleaning the original is in a range of 1 ° to 45 ° with respect to the surface on which the pattern of the original is formed. Irradiating at an angle;
Scanning the surface of the original plate on which the pattern is formed with the laser beam;
The step of irradiating the laser light from a plurality of incident directions having different incident directions around a normal line of the pattern surface while maintaining the incident angle of the laser light with respect to the pattern within the range; A cleaning method characterized by comprising: Exposing the substrate using the exposure apparatus according to any one of claims 1 to 8,
Developing the exposed substrate; and
A device manufacturing method comprising: Cleaning that exposes the pattern of the original held by the original chuck in a vacuum environment onto the substrate held by the substrate chuck via a projection optical system and cleans at least one of the original chuck and the substrate chuck in a vacuum environment In an exposure apparatus having an apparatus,
The cleaning device includes:
Irradiating means for irradiating the original with a laser beam for cleaning the original at an angle in the range of 1 ° to 45 ° with respect to the surface on which the pattern of the original is formed;
A measuring device for measuring the degree of vacuum in the space in which the original plate is disposed;
A controller that determines whether or not the degree of vacuum measured by the measuring device is 100 Pa or less, and that allows the irradiation means to irradiate the laser light when the degree of vacuum is determined to be 100 Pa or less; An exposure apparatus comprising: