JP2011023467A - Foreign matter information detecting method, foreign matter information detecting device, optical system, exposure device, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device detecting foreign matter information on foreign matters adhering to an optical member, and also to provide an optical system, an exposure device, and a device manufacturing method. <P>SOLUTION: A relay-use mirror 20 is equipped with: a plane of incidence 20a upon which exposure light EL is incident; and a reflection layer 27 emitting photoelectrons with incidence of the exposure light EL upon the plane of incidence 20a. The plane of incidence 20a of the relay-use mirror 20 is irradiated with a band-narrowed beam NL1 of a wavelength band narrower than that of the exposure light EL and the amount of photoelectrons emitted from the reflection layer 27 by irradiation of the band-narrowed beam NL1 with the relay-use mirror 20 is detected. Then, the foreign matter information on the foreign matters adhering to the relay-use mirror 20 is detected based on the detected amount of emitted photoelectrons. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a foreign matter information detection method and foreign matter information detection apparatus for detecting information about foreign matter attached to an optical member such as a mirror. The present invention also relates to an optical system including a foreign matter information detection apparatus, an exposure apparatus including the optical system, and a device manufacturing method using the exposure apparatus.

  In general, an exposure apparatus for manufacturing a microdevice such as a semiconductor integrated circuit includes an illumination optical system that illuminates exposure light onto a mask such as a reticle on which a predetermined pattern is formed, and exposure light that illuminates the mask. A projection optical system for projecting a pattern image onto a substrate such as a wafer or a glass plate coated with a photosensitive material. In such an exposure apparatus, a higher resolution of the projection optical system is demanded in order to achieve higher integration of the semiconductor integrated circuit and finer pattern images associated with the higher integration. Therefore, the wavelength of exposure light used in the exposure apparatus has been shortened. In recent years, exposure apparatuses that use EUV (Extreme Ultraviolet) light as exposure light have been developed.

  By the way, the lithography process using EUV light as exposure light is performed in a chamber whose interior is set to a vacuum state. However, the inside of the chamber is not actually in a completely vacuum state. For example, a gas containing hydrocarbons due to a photosensitive material applied to the substrate and components (such as a coating material of an electric cable) inside the apparatus may remain in the chamber. When exposure light is incident on an optical member (such as a reflection mirror) on which the gas is adsorbed on the surface, hydrocarbons are decomposed by a photochemical reaction, and the optical member contains carbon contamination (ie, carbon contamination). (Stains mainly composed of carbon) may be attached. Further, when oxygen or water vapor remains in the chamber, the surface of the optical member on which exposure light is incident may be oxidized due to the decomposition of oxygen or water vapor due to the photochemical reaction.

  When foreign matter such as carbon contamination or oxide film adheres to the optical member in this way, a part of the exposure light incident on the optical member is absorbed by the foreign matter attached to the optical member, and the amount of exposure light emitted from the optical member is , The amount of exposure light absorbed by the foreign matter is reduced. That is, the amount of exposure light that irradiates the substrate (also referred to as substrate irradiation amount) is reduced. If the lithography process is performed in a state where the substrate irradiation amount is small, exposure may be insufficient, and thus it is necessary to set an exposure time according to the substrate irradiation amount. Therefore, for example, an exposure apparatus described in Patent Document 1 has been proposed as an exposure apparatus including a measurement device capable of measuring the amount of exposure light incident on the optical member.

  In this exposure apparatus, the optical member (reflection mirror) constituting each optical system has a configuration in which a reflection film is formed on the surface of a mirror body made of an insulating material (for example, low thermal expansion glass). As a reflective film that reflects EUV light, a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately stacked is generally used. When exposure light enters such an optical member, photoelectrons corresponding to the amount of exposure light actually incident on the reflection film are emitted from the reflection film. Here, if foreign matter such as carbon contamination adheres to the optical member, the amount of exposure light that actually enters the reflective film is reduced by the amount of exposure light that is partially absorbed by the foreign matter. Therefore, the amount of photoelectrons emitted from the optical member changes according to the amount of foreign matter attached to the optical member.

  Therefore, the measurement device provided in the exposure apparatus includes a photoelectron detection unit that detects photoelectrons emitted from the optical member. And the measuring device has detected the light quantity of the exposure light which actually injects into the reflective film of an optical member based on the emitted amount of the photoelectron detected by the photoelectron detection part.

JP 2006-173365 A

  Incidentally, a laser excitation type plasma light source or a discharge type plasma light source is used as a light source device that supplies EUV light as exposure light to the exposure device. Therefore, the exposure light supplied from the light source device is not composed of a single wavelength but is composed of light of a plurality of wavelengths because of the characteristics of the light source. Photoelectrons based on light of each wavelength constituting the incident exposure light are emitted from the optical member on which the exposure light is incident. That is, the measuring device can detect only the sum of photoelectron emission amounts based on light of each wavelength. Moreover, the amount of photoelectrons emitted from the optical member also depends on the wavelength of exposure light incident on the reflective film. For this reason, even if foreign matter adheres to the optical member or the amount of foreign matter attached increases, the amount of photoelectrons emitted from the optical member does not necessarily decrease. Therefore, even if the photoelectrons emitted from the optical member are detected, the amount of foreign matter attached to the optical member cannot always be detected appropriately.

  The present invention has been made in view of such circumstances, and an object thereof is to manufacture a foreign matter information detection method, a foreign matter information detection device, an optical system, an exposure device, and a device that can detect foreign matter information related to foreign matter in an optical member. It is to provide a method.

In order to solve the above-described problems, the present invention adopts the following configuration corresponding to FIGS. 1 to 10 shown in the embodiment.
The foreign matter information detection method of the present invention is a foreign matter information detection method for detecting foreign matter information attached to an optical member (20, 22 to 25, 32 to 37) on which a radiation beam (EL) is incident. 20, 22 to 25, and 32 to 37), the incident surface (20 a) on which the radiation beam (EL) is incident, and photoelectrons are emitted as the radiation beam (EL) is incident on the incident surface (20 a). A photoelectron emitting section (27), and irradiating the optical members (20, 22 to 25, 32-37) with narrow-band beams (NL1, NL2) having a narrower wavelength band than the radiation beam (EL). The amount of photoelectrons emitted from the photoelectron emission section (27) by the irradiation step and the irradiation of the optical member (20, 22-25, 32-37) with the narrow-band beam (NL1, NL2). detection And a foreign matter information detecting step for detecting foreign matter information attached to the optical member (20, 22 to 25, 32 to 37) based on the emission amount of the photoelectron detected in the photoelectron detection step. This is the gist.

  In addition, the foreign matter information detection device of the present invention is a foreign matter information detection device (40, 40A, 40B) that detects foreign matter information adhering to the optical member (20, 22-25, 32-37) on which the radiation beam (EL) is incident. The optical member (20, 22-25, 32-37) includes an incident surface (20a) on which the radiation beam (EL) is incident, and the radiation beam (EL on the incident surface (20a)). ) And a photoelectron emission section (27) that emits photoelectrons upon incidence of light, and is disposed in the optical path of the radiation beam (EL) and has a narrower wavelength band than the wavelength band of the radiation beam (EL) Narrow-band optical system (41, 41A, 41B) that emits the normalized beam (NL1, NL2), a photoelectron detector (46) that detects photoelectrons emitted from the photoelectron emitter (27), and the photoelectron detection Department ( And a foreign matter detection unit (42) for detecting foreign matter information attached to the optical member (20, 22 to 25, 32 to 37) based on the emission amount of the photoelectrons detected by 6). .

  According to the above configuration, when detecting foreign matter information, the incident surface (20a) of the optical member (20, 22 to 25, 32 to 37) has a narrow wavelength band narrower than that of the radiation beam (EL). Banded beams (NL1, NL2) are incident. Therefore, the amount of photoelectrons emitted from the photoelectron emission part (27) of the optical member (20, 22 to 25, 32 to 37) is the same as that of the optical member (20, 22 to 25, 32 to 37). Unlike the conventional case in which the light beam is incident on the optical member (20), a uniform change is shown according to a change in the actual incident amount on the optical member (20, 22-25, 32-37). Therefore, it is possible to improve the detection accuracy of the foreign substance information in the optical member (20, 22 to 25, 32 to 37) based on the acquired emission amount of photoelectrons.

  In order to explain the present invention in an easy-to-understand manner, it has been described in association with the reference numerals of the drawings showing the embodiments, but it goes without saying that the present invention is not limited to the embodiments.

  According to the present invention, it is possible to detect foreign matter information related to foreign matter attached to an optical member.

1 is a schematic block diagram that shows an exposure apparatus according to a first embodiment. The graph which shows the spectrum distribution of exposure light. The schematic block diagram which shows the foreign material information detection apparatus in 1st Embodiment. The graph which shows the spectrum distribution of a narrow-band beam. The graph which shows a mode that a photoelectron spectrum changes according to the adhesion amount of a foreign material. The schematic block diagram which shows the principal part of the foreign material information detection apparatus in 2nd Embodiment. The graph which shows the spectrum distribution of the 1st and 2nd narrow-band beam, respectively. The schematic block diagram which shows the principal part of the foreign material information detection apparatus in 3rd Embodiment. The flowchart of the manufacture example of a device. The detailed flowchart regarding the board | substrate process in the case of a semiconductor device.

(First embodiment)
Below, 1st Embodiment which actualized this invention is described based on FIGS. In this embodiment, the direction parallel to the optical axis of the projection optical system is the Z-axis direction, and the scanning direction of the reticle R and wafer W during scanning exposure in a plane perpendicular to the Z-axis direction is the Y-axis direction. The non-scanning direction orthogonal to the scanning direction will be described as the X-axis direction. The rotation directions around the X, Y, and Z axes are also referred to as the θx direction, the θy direction, and the θz direction.

  As shown in FIG. 1, an exposure apparatus 11 according to this embodiment uses extreme ultraviolet light, ie, EUV (Extreme Ultraviolet) light, which is a soft X-ray region having a wavelength of about 100 nm or less, emitted from a light source device 12 as exposure light. It is an EUV exposure apparatus used as an EL. Such an exposure apparatus 11 includes a chamber 13 (a portion surrounded by a two-dot chain line in FIG. 1) whose inside is set to a vacuum atmosphere lower in pressure than the atmosphere. In the chamber 13, an illumination optical system 14 that illuminates a reflective reticle R on which a predetermined pattern is formed with the exposure light EL supplied from the light source device 12 into the chamber 13, and an irradiation target on which the pattern is formed. A reticle stage 15 that holds the reticle R is provided so that the surface Ra is positioned on the −Z direction side (lower side in FIG. 1). Further, in the chamber 13, the projection optical system 16 that irradiates the wafer W coated with a photosensitive material such as a resist by the exposure light EL through the reticle R, and the irradiated surface Wa are on the + Z direction side (in FIG. 1). A wafer stage 17 for holding the wafer W is provided so as to be positioned on the upper side.

  The light source device 12 is a device that outputs EUV light having a wavelength of 5 to 20 nm as exposure light EL, and includes a laser excitation plasma light source (not shown). In this laser-excited plasma light source, plasma is generated by irradiating a high-density EUV light generating substance (target) with a high-power laser such as a YAG laser or excimer laser using semiconductor laser excitation, and EUV light is emitted from the plasma. Is emitted as exposure light EL. Such exposure light EL is condensed by a condensing optical system (not shown) and output into the chamber 13.

In the present embodiment, a tin compound (for example, tin oxide (SnO ₂ )) is used as the EUV light generating material. As shown in FIG. 2, the exposure light EL output from the light source device 12 has a plurality of peaks in the vicinity of 13.5 nm, and its wavelength band has a width exceeding 0.4 nm. .

  As shown in FIG. 1, the illumination optical system 14 includes a casing 18 (a portion surrounded by an alternate long and short dash line in FIG. 1) whose interior is set to a vacuum atmosphere, as in the interior of the chamber 13. A collimating mirror 19 for condensing the exposure light EL emitted from the light source device 12 is provided in the casing 18, and the collimation mirror 19 converts the incident exposure light EL into a substantially parallel shape. And is emitted toward the relay mirror 20. The exposure light EL that passes through the relay mirror 20 is maintained in a substantially parallel state and is incident on a fly-eye optical system 21 (a portion surrounded by a broken line in FIG. 1) that is a type of optical integrator. The fly-eye optical system 21 includes a pair of fly-eye mirrors 22 and 23, and the incident-side fly-eye mirror 22 disposed on the incident side of the fly-eye mirrors 22 and 23 is irradiated with the reticle R. The surface Ra is disposed at a position optically conjugate with the surface Ra. The exposure light EL reflected by the incident side fly-eye mirror 22 is incident on the emission side fly-eye mirror 23 arranged on the emission side.

  In addition, the illumination optical system 14 is provided with a condenser mirror 24 that emits the exposure light EL emitted from the emission side fly-eye mirror 23 to the outside of the housing 18. Then, the exposure light EL emitted from the condenser mirror 24 is guided to the reticle R held on the reticle stage 15 by a reflection mirror 25 for folding, which is installed in a lens barrel 31 described later.

  In addition, reflection mirrors 19, 20, 24, and 25 other than the fly-eye mirrors 22 and 23 among the reflection mirrors 19, 20, and 22 to 25 constituting the illumination optical system 14 are low thermal expansion glass as shown in FIG. Each of the mirror body 26 has a substantially rectangular plate shape made of an insulating material, and a reflection layer 27 formed on the surface of the mirror body 26. Each of the reflective layer 27 and the reflective layer provided on the reflective surface side of each fly-eye mirror 22, 23 has a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately laminated.

  The reticle stage 15 is disposed on the object plane side of the projection optical system 16 and includes a first electrostatic chucking holding device 29 for electrostatically chucking the reticle R. The first electrostatic attraction / holding device 29 includes a base body 30 made of a dielectric material and having an attracting surface 30a, and a plurality of electrode portions (not shown) arranged in the base body 30. When a voltage is applied to each electrode unit from a voltage application unit (not shown), the reticle R is electrostatically adsorbed on the adsorption surface 30 a by the Coulomb force generated from the base body 30.

  The reticle stage 15 is movable in the Y-axis direction (left and right direction in FIG. 1) by driving a reticle stage drive unit (not shown). That is, the reticle stage drive unit moves the reticle R held by the first electrostatic chucking holding device 29 in the Y-axis direction with a predetermined stroke. The reticle stage drive unit can also move the reticle R in the X-axis direction (direction orthogonal to the paper surface in FIG. 1) and the θz direction. Note that, when the exposure light EL is illuminated on the irradiated surface Ra of the reticle R, a substantially arc-shaped illumination region extending in the X-axis direction is formed on a part of the irradiated surface Ra.

  The projection optical system 16 is an optical system that reduces an image of a pattern formed by illuminating the irradiated surface Ra of the reticle R with exposure light EL to a predetermined reduction magnification (for example, 1/4 times). Similarly to the inside of the lens 13, a lens barrel 31 whose inside is set to a vacuum atmosphere is provided. A plurality of (six in this embodiment) reflective mirrors 32, 33, 34, 35, 36, and 37 are accommodated in the barrel 31. Each of these mirrors 32 to 37 is held by the lens barrel 31 via a mirror holding device (not shown). Then, the exposure light EL guided from the reticle R side which is the object surface side is in the order of the first mirror 32, the second mirror 33, the third mirror 34, the fourth mirror 35, the fifth mirror 36, and the sixth mirror 37. The light is reflected and guided to the irradiated surface Wa of the wafer W held on the wafer stage 17. A reflective layer having a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately laminated is formed on the reflective surface side of each mirror 32 to 37 constituting the projection optical system 16. Reflective surfaces of the mirrors 32 to 37 are formed by the reflective layer.

  The wafer stage 17 includes a second electrostatic adsorption holding device 38 for electrostatically adsorbing the wafer W, and the second electrostatic adsorption holding device 38 is made of a dielectric material and has a adsorption surface 39a. And a plurality of electrode portions (not shown) arranged in the base 39. When a voltage is applied to each electrode unit from a voltage application unit (not shown), the wafer W is electrostatically adsorbed on the adsorption surface 39 a by the Coulomb force generated from the base 39. The wafer stage 17 includes a wafer holder (not shown) that holds the second electrostatic chucking holding device 38, and a Z leveling (not shown) that adjusts the position of the wafer holder in the Z-axis direction and the tilt angles around the X-axis and the Y-axis. And built-in mechanism.

  The wafer stage 17 can be moved in the Y-axis direction by a wafer stage driving unit (not shown). That is, the wafer stage drive unit moves the wafer W held by the second electrostatic chuck holding device 38 in the Y-axis direction with a predetermined stroke. Further, the wafer stage driving unit is configured to be able to move the wafer W held by the second electrostatic chuck holding device 38 in the X-axis direction and the Z-axis direction.

  When a pattern of the reticle R is formed on one shot area of the wafer W, the reticle R is driven in the Y-axis direction (by the reticle stage driving unit in a state where the illumination area is formed on the reticle R by the illumination optical system 14 ( For example, the projection optical system 16 is reduced with respect to the movement of the reticle R along the Y-axis direction by driving the wafer stage driving unit while moving the wafer W from the + Y direction side to the −Y direction side). It is moved in synchronization with the Y-axis direction (for example, from the −Y direction side to the + Y direction side) at a speed ratio according to the magnification. When the pattern formation on one shot area is completed, the pattern formation on the other shot areas of the wafer W is continuously performed.

  Here, in the chamber 13, a gas containing hydrocarbons caused by a photosensitive material applied to the wafer W and parts inside the apparatus (such as a coating material of an electric cable) remains, and the gas is reflected on the reflection mirror. May stick to the reflective surface. When the exposure light EL is incident on the reflection mirror on which the gas is adsorbed, hydrocarbons are decomposed by a photochemical reaction, and carbon contamination containing carbon as a main component (hereinafter abbreviated as carbon contamination) adheres to the reflection mirror. There is a risk. Further, when oxygen or water vapor remaining in the chamber 13 is adsorbed by the reflection mirror, oxygen or water vapor may be decomposed by a photochemical reaction, and the reflection surface of the reflection mirror may be oxidized. When foreign matter such as carbon contamination or oxide film adheres to the reflection mirror, the foreign matter absorbs part of the exposure light EL, so that the reflection efficiency of the exposure light EL of the reflection mirror is reduced, and the wafer W is irradiated with the exposure light EL. There is a possibility that the amount of exposure at the time of doing will decrease. Therefore, the illumination optical system 14 of the present embodiment detects foreign matter information for detecting information on foreign matter in the relay mirror 20 (hereinafter referred to as foreign matter information) among the reflecting mirrors 19, 20, and 22-25. A device 40 is provided.

The foreign matter information includes information on whether or not foreign matter is attached to the reflecting surface of the relay mirror 20, information on the amount of foreign matter attached, and the like.
Next, the foreign matter information detection apparatus 40 of the present embodiment will be described with reference to FIGS.

  As shown in FIGS. 1 and 3, the foreign matter information detection apparatus 40 includes a narrow-band optical system 41 that emits a narrow-band beam NL1 having a wavelength band narrower than the wavelength band of the exposure light EL. The band-narrowing optical system 41 has a measurement position (shown in the figure) preset in the optical path between the collimating mirror 19 and the relay mirror 20 by an optical system moving mechanism 43 that is driven based on a control command from the control device 42. 3) and a retracted position (position shown in FIG. 1) outside the optical path.

  Further, the foreign matter information detection device 40 includes a light receiving unit 44 having a light receiving surface 44a that receives the narrow band beam NL1 emitted from the narrow band optical system 41 arranged at the measurement position. The detection signal (electric signal) corresponding to the amount of light received by the narrow-band beam NL1 on the light receiving surface 44a is output to the control device 42. Further, the light receiving unit 44 is an optical path between the collimating mirror 19 and the relay mirror 20 by a light receiving unit moving mechanism 45 that is driven based on a control command from the control device 42, and is a relay mirror rather than a measurement position. It can move back and forth between a light receiving position preset on the 20 side (a position indicated by a broken line in FIG. 3) and a retracted position outside the optical path (a position indicated by a solid line in FIG. 3). That is, the light receiving unit 44 is disposed on the side of the emission source of the narrow band beam NL1 (that is, the narrow band optical system 41).

  Further, the foreign matter information detection device 40 includes a photoelectron detection unit 46 for detecting photoelectrons emitted from the reflection layer 27 when the narrow-band beam NL1 is incident on the incident surface 20a of the relay mirror 20. Yes. The photoelectron detector 46 has an ammeter 47 that is electrically connected to the reflection layer 27 of the relay mirror 20 via an electric wiring. The ammeter 47 includes a reflection layer of the relay mirror 20. When photoelectrons are emitted from the photoelectric conversion device 27, a minute current flows so as to supplement the emitted photoelectrons. The ammeter 47 outputs a current signal corresponding to the magnitude of a minute current flowing through the ammeter 47 to the control device 42. The control device 42 reflects the reflection layer of the relay mirror 20 based on the current signal from the ammeter 47. The amount of photoelectrons emitted from 27 is calculated.

  The amount of photoelectrons emitted from the reflective layer 27 of the relay mirror 20 depends on the amount of light actually incident on the reflective layer 27 (hereinafter referred to as actual incident light) and the wavelength of the actual incident light. Release amount. In the following description, “photoelectrons are emitted from the reflective layer 27 of the relay mirror 20” is simply referred to as “photoelectrons are emitted from the relay mirror 20”.

  The band-narrowing optical system 41 includes a plurality (four in this embodiment) of reflective optical members 48, 49, 50, and 51. That is, among the reflective optical members 48 to 51, the first reflective optical member 48 is disposed at a position where the exposure light EL emitted from the collimating mirror 19 can enter, and the second reflective optical member 49 is The reflected light RL1 reflected by the first reflective optical member 48 is disposed at a position where it can enter. The third reflective optical member 50 is disposed at a position where the reflected light RL2 reflected by the second reflective optical member 49 can enter, and the fourth reflective optical member 51 is the third reflective optical member 50. The reflected light RL3 reflected is disposed at a position where it can be incident. Then, the reflected light RL4 reflected by the fourth reflective optical member 51 is emitted to the relay mirror 20 side as a narrow-band beam NL1. The incident area where the narrow-band beam NL1 is incident on the relay mirror 20 is substantially the same as the incident area where the exposure light EL is incident on the relay mirror 20 during the exposure process.

Each of these reflective optical members 48 to 51 has a member body 52 having a substantially rectangular plate shape, and a reflection layer 53 formed on the surface of the member body 52. The reflective layer 53 of each reflective optical member 48 to 51 has a multilayer film in which molybdenum silicide (MoSi _x ) and silicon (Si) are alternately laminated. , Reflected lights RL1 to RL4 having a narrower wavelength band than incident light incident thereon are emitted.

  As shown in FIG. 4, the reflective layers 53 of the first and second reflective optical members 48 and 49 are respectively designed such that the peak wavelengths of the reflected lights RL1 and RL2 emitted from them are 13.15 nm. ing. Further, each of the reflective layers 53 of the third and fourth reflective optical members 50 and 51 has a peak wavelength of 13.25 nm of the reflected light RL3 and RL4 emitted from them, and the wavelength of the reflected light RL3 and RL4. Each band is designed so as to overlap a part of the wavelength band of the reflected light RL1, RL2. As a result, the narrowband optical system 41 emits a narrowband beam NL1 having a peak wavelength of 13.2 nm and a half width of 0.094 nm. However, the light intensity of the narrow band beam NL1 is about 4% of the light intensity of the exposure light EL incident on the narrow band optical system 41. In addition, the half value width of narrow-band beam NL1 becomes narrow, so that the zone | band which overlaps with the wavelength zone | band of reflected light RL3, RL4 among the wavelength bands of reflected light RL1, RL2.

  As shown in FIG. 3, the control device 42 includes a digital computer (not shown) constructed from a CPU, a ROM, a RAM, and the like, a driver circuit (not shown) for driving the moving mechanisms 43 and 45, And an input circuit (not shown) to which various electrical signals from the unit 44 and the ammeter 47 are input. In addition, the control device 42 is provided with a storage device 42 a that stores information on the amount of photoelectrons emitted from the relay mirror 20.

Next, a method for detecting foreign matter information in the relay mirror 20 will be described.
Now, when the optical system moving mechanism 43 is driven at a timing when the wafer W is not held on the wafer stage 17, the narrow-band optical system 41 moves from the retracted position to the measuring position (see FIG. 3). When the exposure light EL is output from the light source device 12 in this state, the narrow-band optical system 41 emits a narrow-band beam NL1 whose wavelength band is narrower than the exposure light EL toward the relay mirror 20. . That is, the incident surface 20a of the relay mirror 20 is irradiated with the narrow-band beam NL1 (irradiation step). Then, the photoelectrons corresponding to the incident narrow-band beam NL1 are emitted from the relay mirror 20, and the ammeter 47 has a current having a magnitude corresponding to the amount of photoelectrons emitted from the relay mirror 20. Flowing. Then, the control device 42 calculates the amount of photoelectrons emitted from the relay mirror 20, and the calculation result is temporarily stored in a RAM (not shown) of the control device 42 (photoelectron detection step).

  Subsequently, when the light receiving unit moving mechanism 45 is driven, the light receiving unit 44 moves from the retracted position to the light receiving position. Then, the narrow-band beam NL1 is incident on the light-receiving surface 44a of the light-receiving unit 44 from the narrow-band optical system 41, and an electric signal corresponding to the received light amount of the narrow-band beam NL1 is transmitted from the light receiving unit 44 to the control device. 42 (light receiving step). Then, the control device 42 calculates the light amount of the narrow-band beam NL1.

  Then, the control device 42 divides the emission amount temporarily stored in the RAM by the light amount of the narrow-band beam NL1, thereby calculating a normalized photoelectron emission amount (hereinafter referred to as a normalized emission amount). The Then, based on the magnitude of the normalized release amount, it is determined whether or not foreign matter is attached to the relay mirror 20. Further, when foreign matter is attached to the relay mirror 20, the amount of foreign matter attached is estimated (foreign matter information detection step). The normalized release amount is stored in the storage device 42a (storage step).

  The detected foreign matter information is transmitted to an overall control device (not shown) that controls the exposure apparatus 11 in an integrated manner, and adjusts the amount of exposure light EL output from the light source device 12 and drives the reticle stage during exposure. Adjustment of the driving speed of the wafer section and the wafer stage driving section is performed. Further, when the exposure device 11 is provided with a removal device (not shown) for removing the foreign matter adhering to the relay mirror 20, the drive mode of the removal device is controlled.

  Here, the foreign substance information detection step will be described in detail based on the graph shown in FIG. FIG. 5 shows the relationship between the amount of carbon contamination deposited on the relay mirror 20 and the normalized release amount as an example of foreign matter.

  As shown in FIG. 5, the normalized emission amount based on the emission amount of the photoelectrons emitted from the relay mirror 20 changes according to the amount of carbon contamination attached to the relay mirror 20. However, as is apparent from the figure, the normalized emission amount of photoelectrons also changes depending on the wavelength of light incident on the relay mirror 20.

  The first line 60a in FIG. 5 represents a photoelectron indicating the relationship between the wavelength of light and the normalized emission amount when the amount of carbon contamination on the relay mirror 20 is the first amount of attachment (= 0 (zero)). The spectrum is shown. The second line 60b is a photoelectron spectrum indicating the relationship between the wavelength of light and the normalized emission amount when the amount of carbon contamination on the relay mirror 20 is the second amount of attachment larger than the first amount of attachment. Is shown. The third line 60c is a photoelectron spectrum indicating the relationship between the wavelength of light and the normalized emission amount when the amount of carbon contamination on the relay mirror 20 is the third amount of attachment larger than the second amount of attachment. Is shown. The fourth line 60d is a photoelectron spectrum showing the relationship between the wavelength of light and the normalized emission amount when the amount of carbon contamination on the relay mirror 20 is the fourth amount of attachment larger than the third amount of attachment. Is shown.

  In the present embodiment, a narrow-band beam NL1 whose wavelength band is sufficiently narrower than the exposure light EL is incident on the relay mirror 20. Moreover, the peak wavelength of the narrow-band beam NL1 is 13.2 nm. At this peak wavelength, as shown in FIG. 5, as the amount of carbon contamination attached to the relay mirror 20 increases, the amount of photoelectrons emitted tends to decrease. Therefore, unlike the conventional case where the exposure light EL is made incident on the relay mirror 20 and the amount of photoelectrons emitted at that time is detected, the normalized emission amount is determined by adhesion of foreign matters such as carbon contamination to the relay mirror 20. It changes uniformly with respect to fluctuations in quantity. Therefore, in the present embodiment, when the normalized release amount and the calculated normalized release amount when the carbon contamination adhesion amount is the first attachment amount are substantially equal, foreign matters such as carbon contamination are used for relays. It can be determined that the mirror 20 is not attached. In addition, when the calculated normalized release amount is smaller than the normalized release amount when the carbon contour attachment amount is the first attachment amount, the calculated release amount to the relay mirror 20 is based on the calculated release amount. The amount of foreign matter such as carbon contamination is estimated. Further, the standardized release amount calculated in the previous foreign matter information detection step is read from the storage device 42a, the previous standardized release amount read out, and the current normalized release amount calculated in the current foreign matter information detection step, Is detected, the amount of change (that is, the amount of increase) in the amount of foreign matter such as carbon contamination on the relay mirror 20 is detected.

Therefore, in this embodiment, the following effects can be obtained.
(1) When detecting foreign matter information in the reflective layer 27 of the relay mirror 20, a narrow-band beam NL1 having a narrower wavelength band than the exposure light EL is incident on the incident surface 20a of the relay mirror 20. The Therefore, unlike the conventional case where the exposure light EL is incident on the relay mirror 20, the amount of photoelectrons emitted from the relay mirror 20 is uniform according to the change in the actual amount of incidence on the relay mirror 20. Change. Therefore, the detection accuracy of foreign matter information in the relay mirror 20 based on the acquired amount of released photoelectrons can be improved.

  (2) In the present embodiment, the narrow-band beam NL1 emitted from the narrow-band optical system 41 is received by the light receiving unit 44, and the emission amount of photoelectrons is normalized using the light reception result. The foreign matter information in the relay mirror 20 is detected based on the normalized emission amount thus calculated. Therefore, foreign matter information in the relay mirror 20 can be accurately detected regardless of fluctuations in the amount of exposure light EL emitted from the light source device 12.

  (3) Further, the normalized release amount calculated in the foreign matter information detection step is stored in the storage device 42a. Therefore, the previous normalized release amount calculated in the previous foreign matter information detection step can be compared with the current normalized release amount calculated in the current foreign matter information detection step. Therefore, it is possible to detect the degree of increase or decrease in the amount of foreign matter attached to the relay mirror 20.

  (4) Furthermore, the peak wavelength of the narrowband beam NL1 emitted from the narrowband optical system 41 is a wavelength at which the amount of emitted photoelectrons is uniformly increased or decreased according to the amount of foreign matter such as carbon contamination. Therefore, increase / decrease in the amount of adhering foreign matter on the relay mirror 20 can be reliably detected.

  (5) Each of the reflective optical members 48 to 51 constituting the narrowband optical system 41 is a narrowband optical member capable of emitting reflected light RL1 to RL4 having a narrower wavelength band than incident light. Therefore, the wavelength band of light can be made narrow by reflecting light in order by each reflective optical member 48-51. Accordingly, the wavelength band of the narrowband beam NL1 can be narrowed compared to the case where only some of the reflective optical members 48 to 51 are narrowband optical members.

  (6) Moreover, each of the reflective optical members 48 to 51 has a part of the wavelength band of the first and second reflective optical members 48 and 49 and the wavelength band of the third and fourth reflective optical members 50 and 51. Each part is designed to overlap. Therefore, compared with the case where the wavelength bands of the reflective optical members 48 to 51 are all the same, it is possible to further contribute to narrowing the wavelength band of the narrowband beam NL1.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the second embodiment is different from the first embodiment in that the foreign matter information detection apparatus includes a plurality of narrow-band optical systems. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  As shown in FIG. 6, the foreign matter information detection apparatus 40A of the present embodiment includes a plurality (two in the present embodiment) of narrow-band optical systems 41 and 41A. Further, the foreign matter information detection apparatus 40A includes an optical system moving mechanism 43 (not shown in FIG. 6) for moving the first narrow-band optical system 41 forward and backward between the measurement position and the retracted position, and a second An optical system moving mechanism (not shown) for moving the narrow-band optical system 41A forward and backward between the measurement position and the retracted position is provided. That is, in the present embodiment, it is possible to alternately arrange the narrow-band optical systems 41 and 41A at the measurement positions.

  As shown in FIG. 7, the first band-narrowing optical system 41 is the same as the band-narrowing optical system of the first embodiment. When arranged at the measurement position, the first narrow-band optical system 41 emits the first narrow-band beam NL1 having a peak wavelength of 13.2 nm to the relay mirror 20 side.

  When the second narrowband optical system 41A is arranged at the measurement position, the second narrowband optical system 41A has a peak wavelength of 13.8 nm and has a wavelength band different from the wavelength band of the first narrowband beam NL1. The narrow-band beam NL2 is emitted to the relay mirror 20 side. Specifically, as shown in FIG. 6, the second narrow-band optical system 41A has a plurality (four in this embodiment) of reflective optical members 70, 71, 72, 73. When the exposure light EL from the collimating mirror is reflected in the order of the first reflective optical member 70, the second reflective optical member 71, the third reflective optical member 72, and the fourth reflective optical member 73, the fourth reflective From the mold optical member 73, the second narrow-band beam NL2 is emitted.

Each of the reflective optical members 70 to 73 includes a member main body 52 having a substantially rectangular plate shape, and a reflective layer 53A formed on the surface of the member main body 52. Each reflective layer 53A is silicified. Each has a multilayer film in which molybdenum (MoSi _x ) and silicon (Si) are alternately stacked. Specifically, the reflective layers 53A of the first and second reflective optical members 70 and 71 are designed so that the peak wavelengths of the reflected lights RL1A and RL2A emitted from them are 13.75 nm. In addition, the reflective layer 53A of the third and fourth reflective optical members 72 and 73 has the peak wavelength of the reflected light RL3A and RL4A emitted from them of 13.85 nm and the wavelength band of the reflected light RL3A and RL4A. Are designed so as to overlap a part of the wavelength band of the reflected light RL1A, RL2A. As a result, the second narrow-band optical system 41A emits a second narrow-band beam NL2 having a peak wavelength of 13.8 nm and a half-value width of 0.094 nm as shown in FIG. Is done. However, the light intensity of the second narrowband beam NL2 is about 4% of the light intensity of the exposure light EL incident on the second narrowband optical system 41A.

Next, a method for detecting foreign matter information in the relay mirror 20 of the present embodiment will be described.
Now, when the first narrow-band optical system 41 is arranged at the measurement position at the timing when the wafer W is not held on the wafer stage 17, the first narrow-band beam from the first narrow-band optical system 41. NL1 enters the relay mirror 20 (first irradiation step). Then, the photoelectrons corresponding to the incident first narrow-band beam NL1 are emitted from the relay mirror 20, and the ammeter 47 (not shown in FIG. 6) emits the photoelectrons emitted from the relay mirror 20. A current corresponding to the amount flows. Then, the control device 42 calculates a first emission amount of photoelectrons emitted from the relay mirror 20, and the calculation result is temporarily stored in a RAM (not shown) of the control device 42 (first photoelectron detection step).

  Subsequently, when the light receiving unit 44 (not shown in FIG. 6) is disposed at the light receiving position, the first narrow-band beam NL1 is incident on the light receiving surface 44a of the light receiving unit 44, and the light receiving unit 44 An electrical signal corresponding to the amount of light received by the banded beam NL1 is output to the control device 42 (light receiving step). Then, the control device 42 calculates the first light amount of the narrow-band beam NL1. Further, a first emission amount of normalized photoelectrons (hereinafter referred to as a first normalized emission amount) is calculated by dividing the first emission amount temporarily stored in the RAM by the first light amount.

  Then, after the first narrowband optical system 41 has moved to the retracted position, the second narrowband optical system 41A is driven by driving the optical system moving mechanism for the second narrowband optical system 41A. Arranged at the measurement position. That is, in the present embodiment, the band-narrowing optical systems 41 and 41A arranged at the measurement position are selectively switched (arrangement step). When the exposure light EL is output from the light source device 12 in this state, the second narrow-band optical system 41A emits the second narrow-band beam NL2 toward the light receiving unit 44 disposed at the light receiving position. Is done. Then, the second narrow-band beam NL2 is incident on the light-receiving surface 44a of the light-receiving unit 44, and an electric signal corresponding to the amount of light received by the second narrow-band beam NL2 is transmitted from the light-receiving unit 44 to the control device 42. (Light receiving step). Then, the control device 42 calculates the second light amount of the second narrow-band beam NL2, and the calculation result is temporarily stored in a RAM (not shown) of the control device 42.

  Subsequently, when the light receiver 44 is moved to the retracted position, the relay mirror 20 is irradiated with the second narrow-band beam NL2 (second irradiation step). Then, photoelectrons corresponding to the incident second narrow-band beam NL2 are emitted from the relay mirror 20, and the ammeter 47 has a magnitude corresponding to the amount of photoelectrons emitted from the relay mirror 20. Current flows. Then, the control device 42 calculates a second emission amount of photoelectrons emitted from the reflective layer 27 of the relay mirror 20 (second photoelectron detection step).

  Then, the control device 42 divides the second emission amount by the second light amount temporarily stored in the RAM, thereby obtaining a standardized second emission amount of photoelectrons (hereinafter referred to as a second normalized emission amount). Calculated. Then, based on the magnitudes of the first and second normalized release amounts, it is determined whether or not foreign matter is attached to the relay mirror 20. Further, when foreign matter is attached to the relay mirror 20, the amount of foreign matter attached is estimated (foreign matter information detection step). The first and second normalized release amounts are respectively stored in the storage device 42a (storage step).

  In the foreign matter information detection step of this embodiment, unlike the case of the first embodiment, foreign matter information in the relay mirror 20 is detected based on a plurality of (two in this embodiment) normalized release amounts. That is, the peak wavelength (13.2 nm) of the first narrow-band beam NL1 is the first emission amount of photoelectrons from the relay mirror 20 as the amount of carbon contamination attached to the relay mirror 20 increases. Is a wavelength that gradually decreases (see FIG. 5). The peak wavelength (13.8 nm) of the second narrow-band beam NL2 is the second emission amount of photoelectrons from the relay mirror 20 as the amount of carbon contamination attached to the relay mirror 20 increases. Is a wavelength that gradually increases (see FIG. 5). Based on the first and second normalized emission amounts using the first and second narrow-band beams NL1 and NL2, the amount of carbon contamination attached to the relay mirror 20 is estimated. For example, when the current first normalized release amount decreases from the previous first normalized release amount and the current second normalized release amount increases from the previous second normalized release amount, It is determined that the amount of carbon contamination that adheres to the relay mirror 20 has increased. It is also possible to detect an increase in carbon contamination.

Therefore, in this embodiment, in addition to the effects (1) to (6) in the first embodiment, the following effects can be further obtained.
(7) In this embodiment, the narrowband beams NL1 and NL2 having different wavelength bands are respectively incident on the relay mirror 20, and based on the first and second emission amounts of photoelectrons, the relay mirror 20 Increase / decrease in the amount of adhering foreign matter at is detected. Therefore, the detection accuracy can be improved as compared with the case where detection is performed with one kind of narrow-band beam.

  (8) Moreover, the peak wavelength of the first narrow-band beam NL1 is a wavelength at which the first emission amount of photoelectrons gradually decreases as the adhesion amount of foreign matters such as carbon contamination increases. The peak wavelength of the narrow-band beam NL2 is a wavelength at which the second emission amount of photoelectrons gradually increases as the adhesion amount of foreign matters such as carbon contamination increases. Therefore, by acquiring the amount of change in the first and second standard release amounts, it is possible to reliably detect an increase or decrease in the amount of foreign matter attached to the relay mirror 20.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is different from the first and second embodiments in the types of optical members constituting the foreign substance information detection apparatus. Therefore, in the following description, parts different from the first and second embodiments will be mainly described, and the same reference numerals are given to the same or corresponding member configurations as those of the first and second embodiments. A duplicate description will be omitted.

  As shown in FIG. 8, the foreign matter information detection apparatus 40B of the present embodiment includes a narrow-band optical system 41B that can change the wavelength band of the emitted narrow-band beam NL1. The narrow-band optical system 41B includes a first reflective optical member 80 on which the exposure light EL emitted from the collimating mirror 19 is incident, and a diffraction grating on which the reflected light RL1B from the first reflective optical member 80 is incident. (Also referred to as a grating) 81. The diffraction grating 81 is an optical member that changes the exit angle of the emitted light depending on the wavelength of incident light, and extends in a direction substantially orthogonal to the traveling direction of the reflected light RL1B (in FIG. 8, the direction orthogonal to the paper surface). It can be rotated around the center. The foreign matter information detection apparatus 40B includes a second reflective optical member 82 on which reflected light RL2B having a predetermined wavelength (for example, 13.2 nm) out of the reflected light reflected by the diffraction grating 81 is incident, and the second reflective type A third reflective optical member 83 on which the reflected light RL3B from the optical member 82 is incident is further provided. Then, the reflected light RL4B from the third reflective optical member 83 is incident on the relay mirror 20 as a narrow-band beam NL1. The first to third reflective optical members 80, 82, 83 have a multilayer film in which molybdenum (Mo) and silicon (Si) are alternately laminated on the surface of a member body 52 having a substantially rectangular plate shape. In this configuration, the layer 53B is formed.

  The foreign matter information detection device 40B is provided with a displacement mechanism 84 that is driven to rotate the diffraction grating 81. The displacement mechanism 84 is driven based on a control command from the control device 42.

  Next, a method for detecting foreign matter information in the relay mirror 20 of the present embodiment will be described. The rotational position of the diffraction grating 81 that can emit the first narrow-band beam NL1 with a peak wavelength of 13.2 nm is referred to as a first rotational position, and the second narrow-band with a peak wavelength of 13.8 nm. The rotational position of the diffraction grating 81 that can emit the beam NL2 is referred to as a second rotational position.

  When the narrow-band optical system 41B is arranged at the measurement position at a timing when the wafer W is not held on the wafer stage 17, the rotational position of the diffraction grating 81 is adjusted to the first rotational position by the displacement mechanism 84. . Then, the first narrow-band beam NL1 is emitted toward the relay mirror 20 from the narrow-band optical system 41B. When the first narrow-band beam NL1 is received by the light receiving unit 44 disposed at the light-receiving position, the first light amount of the first narrow-band beam NL1 is calculated. Further, when the incident surface 20a of the relay mirror 20 is irradiated with the first narrow-band beam NL1, the first emission amount of photoelectrons from the relay mirror 20 is calculated. Then, the first normalized emission amount is calculated by dividing the first emission amount by the first light amount.

  Thereafter, when the rotational position of the diffraction grating 81 is adjusted to the second rotational position by driving the displacement mechanism 84, the second narrowband beam NL2 is transmitted from the narrowband optical system 41B to the relay mirror 20. It is injected towards. When the second narrow-band beam NL2 is received by the light receiving unit 44 arranged at the light-receiving position, the second light amount of the second narrow-band beam NL2 is calculated. When the incident surface 20a of the relay mirror 20 is irradiated with the second narrow-band beam NL2, the second emission amount of photoelectrons from the relay mirror 20 is calculated. Then, the second normalized emission amount is calculated by dividing the second emission amount by the second light amount.

  By using each normalized release amount calculated in this way, it is possible to estimate whether foreign matter has adhered to the relay mirror 20 as in the case of the second embodiment. Further, when a foreign substance adheres to the relay mirror 20, the amount of the foreign substance attached can be estimated.

Therefore, in this embodiment, in addition to the effects (1) to (3), (7), and (8) in the first and second embodiments, the following effects can be further obtained.
(9) In this embodiment, the diffraction grating 81 is used as a narrow-band optical member. Therefore, unlike the above-described embodiments, a narrow-band beam having a sufficiently narrow wavelength band can be emitted from the narrow-band optical system 41B without using a plurality of narrow-band optical members.

  (10) Also, by rotating the diffraction grating 81, the peak wavelength of the narrowband beam emitted from the narrowband optical system 41B can be changed. Therefore, the foreign substance information detection apparatus 40B can be downsized as compared with the case where a plurality of narrow-band optical systems are provided.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is different from the third embodiment in the detection method of foreign matter information in the relay mirror 20 using the foreign matter information detection device 40B. Therefore, in the following description, parts different from those of the third embodiment will be mainly described, and the same or corresponding member configurations as those of the third embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  In the storage device 42a of the control device 42 of the present embodiment, a plurality of photoelectron spectra indicating the relationship between the peak wavelength of the narrow-band beam and the amount of photoelectrons emitted are stored in advance (see FIG. 5). That is, the storage device 42a has a photoelectron spectrum when the amount of carbon contamination on the relay mirror 20 is the first amount of attachment (= 0 (zero)), and a photoelectron when the amount of attachment is the second amount of attachment. The spectrum, the photoelectron spectrum when the adhesion amount is the third adhesion amount, and the photoelectron spectrum when the adhesion amount is the fourth adhesion amount are stored. In the present embodiment, four types of photoelectron spectra are stored for convenience of understanding the description, but five or more types of photoelectron spectra may be stored in the storage device 42a.

  At the time of measurement, the narrow-band optical system 41B is disposed at the measurement position, and the light receiving unit 44 is positioned at the light receiving position. In this state, the diffraction grating 81 rotates so that the peak wavelength of the narrowband beam emitted from the narrowband optical system 41B continuously changes between 12.5 nm and 14.5 nm. Then, the narrow-band beams having different peak wavelengths are continuously incident on the light receiving unit 44. Then, the control device 42 calculates the light amount of the narrow-band beam for each peak wavelength.

  Thereafter, the peak wavelength of the narrowband beam emitted from the narrowband optical system 41B is continuously changed between 12.5 nm and 14.5 nm with the light receiving unit 44 retracted to the retracted position. The diffraction grating 81 rotates again. Then, the narrowband beams having different peak wavelengths are continuously incident on the relay mirror 20. At this time, for example, when a narrow-band beam having a peak wavelength of 13.1 nm is incident on the relay mirror 20, photoelectrons corresponding to the peak wavelength and light amount of the narrow-band beam at this time are emitted from the relay mirror 20. The For example, when a narrow-band beam having a peak wavelength of 13.5 nm is incident on the relay mirror 20, photoelectrons corresponding to the peak wavelength and light amount of the narrow-band beam at this time are emitted from the relay mirror 20. . In the control device 42, the amount of photoelectrons emitted from the relay mirror 20 is calculated for each peak wavelength of the narrowband beam based on the current signal from the ammeter 47. By dividing the amount of photoelectron emission corresponding to each peak wavelength by the amount of light corresponding to each peak wavelength, the normalized emission amount at each peak wavelength is calculated. That is, a photoelectron spectrum (hereinafter referred to as an actual photoelectron spectrum) based on the relay mirror 20 at the present time is required.

Then, foreign substance information in the relay mirror 20 is detected by comparing the actual photoelectron spectrum with each photoelectron spectrum stored in the storage device 42a.
Therefore, in this embodiment, in addition to the effects (1) to (3), (9), and (10) in the first to third embodiments, the following effects can be further obtained.

  (11) In this embodiment, the actual photoelectron spectrum is obtained by continuously changing the peak wavelength of the narrow-band beam incident on the relay mirror 20. Foreign substance information is detected based on the shape of the actual photoelectron spectrum. Therefore, the detection accuracy of foreign matter information can be improved as compared with the case where information about foreign matter is acquired using only one or two peak wavelengths.

In addition, you may change each said embodiment into another embodiment as follows.
In each embodiment, the calculated normalized emission amount and the actual photoelectron spectrum may not be stored in the storage device 42a. In this case, the amount of foreign matter adhering to the relay mirror 20 is calculated based on the normalized emission amount and the actual photoelectron spectrum at that time.

In each embodiment, a photoelectron spectrum when an oxide film is formed on the relay mirror 20 may be prepared in advance, and foreign matter information may be detected based on the photoelectron spectrum.
In each embodiment, an ammeter electrically connected to the reflective layer 27 of another mirror may be provided so that photoelectrons emitted from another mirror different from the relay mirror 20 can be detected. Further, ammeters corresponding to the mirrors 32 to 37 constituting the projection optical system 16 may be provided.

Furthermore, a narrow-band optical member may be disposed between all the mirrors or between specific mirrors.
In each embodiment, the light receiving step is performed after the irradiation step, but the irradiation step may be performed after the light receiving step.

In the third embodiment, the rotational position of the diffraction grating 81 may be fixed at a rotational position where a narrow-band beam having a predetermined peak wavelength (for example, 13.8 nm) can be emitted.
In each of the third and fourth embodiments, the narrow-band optical system 41B may have a configuration including a plurality of (for example, two) diffraction gratings. However, when rotating each diffraction grating, it is desirable to rotate in synchronization with each other. With this configuration, it is possible to further contribute to narrowing the band of the narrow band beam.

The exposure light EL that has passed through the relay mirror 20 is incident on the incident side fly-eye mirror 22 having a plurality of mirror elements. Therefore, the relay mirror 20 may be provided with an incident portion corresponding to each mirror element of the incident-side fly-eye mirror 22 so that the adjacent incident portions are electrically insulated. Each incident portion has a multilayer film in which molybdenum silicide (MoSi _x ) and silicon (Si) are alternately stacked. And you may provide the ammeter corresponding to each incident part individually. In this case, the relay mirror 20 can detect foreign substance information for each position. Moreover, by providing each incident portion of the relay mirror 20 at a position corresponding to each mirror element of the incident-side fly-eye mirror 22, the light amount loss of the exposure light EL can be reduced as much as possible.

  In the first to third embodiments, foreign object information may be detected using three or more (eg, four) narrow-band beams having different wavelength bands. In this case, the peak wavelength of each narrow-band beam is preferably a wavelength at which the amount of emitted photoelectrons uniformly changes as the amount of foreign matter attached to the relay mirror 20 increases.

  In each of the first and second embodiments, the first narrow-band optical system 41 may be composed of reflective optical members 48 to 51 having different wavelength bands. However, it is desirable to set the wavelength bands of the reflective optical members 48 to 51 so that some of them overlap each other. Similarly, the second narrow-band optical system 41A may be composed of reflective optical members 70 to 73 having different wavelength bands.

  In each of the first and second embodiments, the first narrowband optical system 41 may have a configuration in which only some of the reflective optical members 48 to 51 are narrowband optical members. Similarly, the second band-narrowing optical system 41 </ b> A may have a configuration in which only some of the reflective optical members 70 to 73 become band-narrowing optical members. The narrow-band optical member is an optical member that can emit a narrow-band beam having a narrower wavelength band than the incident exposure light EL.

  In each embodiment, the incident area at the relay mirror 20 by the narrow-band beam emitted from the narrow-band optical systems 41, 41A, and 41B is incident on the relay mirror 20 during the exposure process. You may comprise so that it may become larger than an area | region.

  In each embodiment, when there is a function of detecting the light amount of the exposure light EL supplied into the chamber 13 on the light source device 12 side and adjusting the light amount of the exposure light EL based on the detection result, the light receiving unit 44 is provided. It may be omitted.

  -In each embodiment, after adjusting the light quantity of the exposure light EL supplied from the light source device 12 so that the light quantity of the exposure light EL detected based on the light receiving part 44 becomes a predetermined light quantity set in advance, the light receiving part 44 is It may be moved to the retracted position to detect the amount of foreign matter adhering to the relay mirror 20. In this case, since the light amount of the narrow-band beam incident on the relay mirror 20 is restricted every time detection is performed, it is not necessary to standardize the detected emission amount of photoelectrons.

In each embodiment, the photoelectron detection unit 46 may include an amplifier (also referred to as an amplifier) that amplifies an electric signal output from the ammeter 47 to the control device 42.
In each embodiment, another light source device different from the light source device 12 may be provided, and foreign matter information in the relay mirror 20 may be detected using light output from the other light source device. However, the other light source device desirably has a light source capable of emitting a narrow-band beam having a narrower wavelength band than the exposure light EL. Furthermore, it is desirable that the other light source device is disposed outside the optical path of the exposure light EL.

  In each embodiment, the exposure apparatus 11 manufactures a reticle or mask used in not only a microdevice such as a semiconductor element but also a light exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, and an electron beam exposure apparatus. Therefore, an exposure apparatus that transfers a circuit pattern from a mother reticle to a glass substrate or a silicon wafer may be used. The exposure apparatus 11 is used for manufacturing a display including a liquid crystal display element (LCD) and the like, and is used for manufacturing an exposure apparatus that transfers a device pattern onto a glass plate, a thin film magnetic head, and the like. It may be an exposure apparatus that transfers to a wafer or the like, and an exposure apparatus that is used to manufacture an image sensor such as a CCD.

In each embodiment, the light source device 12 includes, for example, g-line (436 nm), i-line (365 nm), KrF excimer laser (248 nm), F ₂ laser (157 nm), Kr ₂ laser (146 nm), Ar ₂ laser (126 nm) Or the like. The light source device 12 amplifies the infrared or visible single wavelength laser light oscillated from the DFB semiconductor laser or fiber laser, for example, with a fiber amplifier doped with erbium (or both erbium and ytterbium). Alternatively, a light source capable of supplying harmonics converted into ultraviolet light using a nonlinear optical crystal may be used.

  Further, when such light is used as the exposure light EL, the narrow band optical member may be a transmissive optical member. For example, an optical member that can change the wavelength of light that is transmitted depending on the rotational position or an optical member that can change the wavelength of light that is transmitted depending on the position may be used as the narrowband optical member.

  In each embodiment, the EUV light generating material used in the light source device 12 may be gaseous tin (Sn), or liquid or solid tin. Xenon (Xe) may be used as the EUV light generating substance.

In each embodiment, the light source device 12 may be a device having a discharge plasma light source.
In each of the first and second embodiments, the exposure apparatus 11 may be an exposure apparatus that uses exposure light EL having an arbitrary wavelength band as long as it has light having a wavelength of 50 nm or less. The band-narrowing optical member in this case is a member having a multilayer film in which molybdenum silicide (MoSi _x ) and silicon (Si) are alternately laminated as a reflective layer, but having a narrower wavelength band than the exposure light EL. A beam can be emitted.

In each embodiment, the exposure apparatus 11 may be embodied as a step-and-repeat apparatus.
Next, an embodiment of a microdevice manufacturing method using the device manufacturing method by the exposure apparatus 11 of the embodiment of the present invention in the lithography process will be described. FIG. 9 is a flowchart illustrating a manufacturing example of a micro device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, or the like).

  First, in step S101 (design step), function / performance design (for example, circuit design of a semiconductor device) of a micro device is performed, and pattern design for realizing the function is performed. Subsequently, in step S102 (mask manufacturing step), a mask (reticle R or the like) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S103 (substrate manufacturing step), a substrate (a wafer W when a silicon material is used) is manufactured using a material such as silicon, glass, or ceramics.

  Next, in step S104 (substrate processing step), using the mask and substrate prepared in steps S101 to S104, an actual circuit or the like is formed on the substrate by lithography or the like, as will be described later. Next, in step S105 (device assembly step), device assembly is performed using the substrate processed in step S104. Step S105 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary. Finally, in step S106 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice manufactured in step S105 are performed. After these steps, the microdevice is completed and shipped.

FIG. 10 is a diagram illustrating an example of a detailed process of step S104 in the case of a semiconductor device.
In step S111 (oxidation step), the surface of the substrate is oxidized. In step S112 (CVD step), an insulating film is formed on the substrate surface. In step S113 (electrode formation step), an electrode is formed on the substrate by vapor deposition. In step S114 (ion implantation step), ions are implanted into the substrate. Each of the above steps S111 to S114 constitutes a pretreatment process at each stage of the substrate processing, and is selected and executed according to a necessary process at each stage.

  When the above-mentioned pretreatment process is completed in each stage of the substrate process, the posttreatment process is executed as follows. Thereafter, in the processing step, first, in step S115 (resist formation step), a photosensitive material is applied to the substrate. Subsequently, in step S116 (exposure step), the circuit pattern of the mask is transferred to the substrate by the lithography system (exposure apparatus 11) described above. Next, in step S117 (development step), the substrate exposed in step S116 is developed to form a mask layer made of a circuit pattern on the surface of the substrate. Subsequently, in step S118 (etching step), the exposed member other than the portion where the resist remains is removed by etching. In step S119 (resist removal step), the photosensitive material that has become unnecessary after the etching is removed. That is, in step S118 and step S119, the surface of the substrate is processed through the mask layer. By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the substrate.

DESCRIPTION OF SYMBOLS 11 ... Exposure apparatus 14, 16 ... Optical system 20, 22-25, 32-37 ... Mirror as an optical member, 20a ... Incident surface, 27 ... Reflection layer as photoelectron emission part, 40, 40A, 40B ... Foreign matter Information detecting device 41, 41A, 41B ... Narrow band optical system, 42 ... Control device as foreign matter detecting unit, light amount detecting unit, 42a ... Storage device, 44 ... Light receiving unit, 45 ... Light receiving unit moving mechanism, 46 ... Photoelectron Detection unit, 48 to 51, 70 to 73: reflection type optical member as a narrow band optical member, 80, 82, 83 ... reflection type optical member, 81: diffraction grating, 81a: axis, diffraction grating as wavelength variable element 84 ... Displacement mechanism, EL ... Exposure light as radiation beam, NL1, NL2 ... Narrow band beam, R ... Reticle as mask, W ... Wafer as substrate.

Claims (20)

A foreign matter information detection method for detecting foreign matter information attached to an optical member on which a radiation beam is incident,
The optical member includes an incident surface on which the radiation beam is incident, and a photoelectron emission unit that emits photoelectrons upon incidence of the radiation beam on the incident surface,
An irradiation step of irradiating the optical member with a narrow-band beam having a narrower wavelength band than the radiation beam;
A photoelectron detection step of detecting an emission amount of photoelectrons emitted from the photoelectron emission portion by irradiation of the optical member with the narrow-band beam;
A foreign matter information detection method, comprising: a foreign matter information detection step for detecting foreign matter information adhering to the optical member based on the photoelectron emission amount detected in the photoelectron detection step. The foreign matter information detection method according to claim 1, wherein the irradiation step irradiates the optical member with the narrow-band beam via a narrow-band optical system. A light receiving portion for receiving the narrowband beam is disposed on the emission source side of the narrowband beam, and further includes a light receiving step for receiving the narrowband beam at the light receiving portion;
In the foreign matter information detection step, foreign matter information attached to the optical member is detected based on the light amount of the narrow-band beam received by the light receiving unit in the light receiving step and the photoelectron emission amount detected in the photoelectron detection step. The foreign matter information detection method according to claim 1 or 2, wherein: The irradiating step irradiates the optical member with a first irradiating step of irradiating the optical member with a first narrow-band beam and a second narrow-band beam having a wavelength band different from that of the first narrow-band beam. A second irradiation step,
The photoelectron detection step includes a first photoelectron detection step of detecting a first emission amount of photoelectrons emitted from the photoelectron emission unit by irradiation of the optical member with the first narrowband beam, and the second narrowband. A second photoelectron detection step of detecting a second emission amount of photoelectrons emitted from the photoelectron emission portion by irradiating the optical member with an activation beam,
2. The foreign matter information detection step detects foreign matter information attached to the optical member based on the first and second emission amounts detected in the first and second photoelectron detection steps, respectively. The foreign matter information detection method described in 1. The irradiation step includes: a first narrow-band optical system that emits the first narrow-band beam as the radiation beam is incident; and a second narrow-band beam that is emitted as the radiation beam is incident. 5. The foreign matter information detection method according to claim 4, further comprising an arrangement step of selectively arranging two narrow-band optical systems in the optical path of the radiation beam. The narrowband optical system has a wavelength variable element that changes a peak wavelength of the narrowband beam to be emitted by being displaced with respect to the optical path of the radiation beam,
In the irradiation step, the wavelength variable element is displaced so that a peak wavelength of the narrow-band beam continuously changes,
The photoelectron detection step detects the amount of photoelectrons emitted from the optical member for each peak wavelength of the narrowband beam,
The foreign matter information detection step obtains a photoelectron spectrum indicating each emission amount of the photoelectrons with respect to each peak wavelength based on a detection result in the photoelectron detection step, and obtains foreign matter information attached to the optical member based on the photoelectron spectrum. The foreign matter information detection method according to claim 2, wherein detection is performed. A storage step of storing in a storage device the emission amount of the photoelectrons detected in the photoelectron detection step;
The foreign matter information detection step is based on a comparison result between the photoelectron emission amount detected in the current photoelectron detection step and the photoelectron emission amount detected in the previous photoelectron detection step stored in the storage device. The foreign matter information detection method according to claim 1, wherein the foreign matter information amount attached to the optical member is detected. A foreign matter information detection apparatus for detecting foreign matter information attached to an optical member on which a radiation beam is incident,
The optical member includes an incident surface on which the radiation beam is incident, and a photoelectron emission unit that emits photoelectrons upon incidence of the radiation beam on the incident surface,
A narrow-band optical system that is arranged in the optical path of the radiation beam and emits a narrow-band beam having a wavelength band narrower than the wavelength band of the radiation beam;
A photoelectron detector that detects photoelectrons emitted from the photoelectron emitter;
A foreign matter information detection apparatus comprising: a foreign matter detection unit that detects foreign matter information adhering to the optical member based on an emission amount of the photoelectrons detected by the photoelectron detection unit. A light receiving portion for receiving the radiation beam;
A light receiving unit moving mechanism that supports the light receiving unit and moves between a light receiving position set between the narrow-band optical system and the optical member with respect to the optical path and a retracted position outside the optical path;
A light amount detection unit that detects a light amount of the narrow-band beam based on a light reception result by the light reception unit when the light reception unit is disposed at the light reception position;
9. The foreign matter information detection apparatus according to claim 8, wherein the foreign matter detection unit detects foreign matter information adhering to the optical member based on detection results by the photoelectron detection unit and the light amount detection unit. The narrow-band optical system includes at least one narrow-band optical member that emits a narrow-band beam having a narrower wavelength band than the incident radiation beam. Foreign matter information detection device. The narrow-band optical system has a plurality of reflective optical members,
The foreign matter information detection apparatus according to claim 10, wherein the narrow-band optical member is at least one of the plurality of reflective optical members. The radiation beam is composed of light having a wavelength of 50 nm or less,
The photoelectron emitting portion has a multilayer film of molybdenum (Mo) and silicon (Si),
The said narrow-band optical member has a multilayer film of molybdenum silicide (MoSi _x ) and silicon (Si) provided on the incident surface side on which the radiation beam is incident. The foreign substance information detection apparatus described in 1. The band-narrowing optical system has a plurality of the band-narrowing optical members,
One narrow band optical member of the plurality of narrow band optical members is configured such that a part of the wavelength band of the emitted beam overlaps a part of the wavelength band of the beam emitted from the other narrow band optical member. The foreign matter information detection device according to claim 12, wherein the foreign matter information detection device is configured as described above. The narrow-band optical system includes: a first narrow-band optical system that emits a first narrow-band beam as the radiation beam enters; and the first narrow-band beam as the radiation beam enters. A second narrow-band optical system that emits a second narrow-band beam having a different wavelength band;
The foreign object detection unit includes a first emission amount of photoelectrons detected by the photoelectron detection unit when the first band narrowing optical system is disposed in the optical path, and a second band narrowing optical system. The foreign matter information adhering to the optical member is detected based on a second emission amount of photoelectrons detected by the photoelectron detector when arranged in the optical path. The foreign substance information detection apparatus as described in any one of them. 11. The foreign material according to claim 10, wherein the narrow-band optical member is a wavelength variable element that changes a peak wavelength of the narrow-band beam to be emitted by being displaced with respect to the optical path of the radiation beam. Information detection device. 16. The foreign object according to claim 15, wherein the wavelength tunable element is a diffraction grating, and the diffraction grating is rotatable around an axis extending in a direction intersecting a traveling direction of the incident radiation beam. Information detection device. A displacement mechanism for displacing the wavelength tunable element so that a peak wavelength of the narrow-band beam incident on the optical member changes;
When the wavelength variable element is displaced by the displacement mechanism, the photoelectron detector detects the photoelectrons emitted from the photoelectron emitter for each displacement position of the wavelength variable element,
The foreign matter detection unit obtains a photoelectron spectrum indicating each emission amount of photoelectrons for each peak wavelength based on a detection result by the photoelectron detection unit, and detects foreign matter information attached to the optical member based on the photoelectron spectrum. The foreign matter information detection device according to claim 15 or 16, wherein the foreign matter information detection device is characterized. An optical member having an incident surface on which the radiation beam is incident and a photoelectron emitting portion that emits photoelectrons upon incidence of the radiation beam on the incident surface;
An optical system comprising: the foreign matter information detection device according to any one of claims 8 to 17. An illumination optical system for directing a radiation beam to a mask on which a predetermined pattern is formed;
A projection optical system that irradiates a substrate coated with a photosensitive material with a radiation beam through the mask, and
The exposure apparatus according to claim 18, wherein at least one of the optical systems is the optical system according to claim 18. In a device manufacturing method including a lithography process,
The device manufacturing method according to claim 19, wherein the lithography process uses the exposure apparatus according to claim 19.

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