JP4466647B2 - Exposure apparatus, liquid processing method, exposure method, and device manufacturing method - Google Patents

Description

The present invention relates to an immersion type exposure apparatus that irradiates a substrate with exposure light through a liquid, a liquid processing method for processing a liquid used in the immersion type exposure apparatus, an exposure method using the liquid processing method, and The present invention relates to a device manufacturing method using the exposure apparatus.
This application claims priority with respect to Japanese Patent Application No. 2004-44804 for which it applied on February 20, 2004, and uses the content here.

  Devices such as semiconductor elements, liquid crystal display elements, imaging devices (CCD (charge coupled device)), thin film magnetic heads, etc., have a pattern formed on a mask on a photosensitive substrate (such as a semiconductor wafer or glass plate coated with a resist). It is manufactured by a so-called photography technique. An exposure apparatus used in this photolithography process has a mask stage for supporting a mask and a substrate stage for supporting a photosensitive substrate, and a projection optical system for projecting a mask pattern while sequentially moving the mask stage and the substrate stage. Via the substrate.

  In recent years, in order to cope with higher integration of patterns formed on devices, it is desired to further increase the resolution of the projection optical system. The resolution of the projection optical system becomes higher as the wavelength of the exposure light used becomes shorter and the numerical aperture of the projection optical system becomes larger. For this reason, the wavelength of the exposure light used in the exposure apparatus has become shorter year by year, and the numerical aperture of the projection optical system has also increased. Currently, the mainstream exposure apparatus includes a KrF excimer laser (wavelength 248 nm) as a light source, but an exposure apparatus including a shorter wavelength ArF excimer laser (wavelength 193 nm) is also being put into practical use.

Also, when performing exposure, the depth of focus (DOF) is important as well as the resolution. The resolution R and the depth of focus δ are expressed by the following equations (1) and (2), respectively.
R = k ₁ · λ / NA (1)
δ = ± k ₂ · λ / NA ² (2) where λ is the wavelength of exposure light, NA is the numerical aperture of the projection optical system, and k ₁ and k ₂ are process coefficients.

  From the above formulas (1) and (2), it can be seen that if the wavelength λ of the exposure light is shortened to increase the numerical aperture NA in order to increase the resolution R, the depth of focus δ becomes narrower. If the depth of focus δ becomes too narrow, it becomes difficult to match the substrate surface with the image plane of the projection optical system, and the margin during the exposure operation may be insufficient. Therefore, as a method for substantially shortening the exposure wavelength and increasing the depth of focus, for example, an immersion type exposure apparatus disclosed in the following Patent Document 1 has been proposed.

In this immersion type exposure apparatus, the space between the lower surface of the projection optical system and the substrate surface is filled with a liquid such as water or an organic solvent, and the wavelength of exposure light in the liquid is 1 / n (n is n in the air). The resolution is improved by utilizing the fact that the refractive index of the liquid is usually about 1.2 to 1.6), and the depth of focus is expanded about n times.
International Publication No. 99/49504 Pamphlet

  The immersion exposure apparatus includes, for example, a liquid supply / recovery device that recovers the supplied liquid at the same time as supplying the liquid onto the substrate to be exposed. By this liquid supply and recovery device, at least a part of the substrate can be immersed in a predetermined amount of liquid whose temperature is controlled to be constant. The liquid recovered by the liquid supply / recovery device is temporarily stored in the recovery unit (recovery tank) and further discharged from the recovery tank.

  However, if the liquid is discharged from the recovery tank, vibration may occur as the liquid is discharged. If such vibrations occur during exposure operations or operations that require highly accurate alignment such as substrate mark measurement, the final exposure accuracy (resolution, transfer fidelity, overlay accuracy, etc.) ) May be reduced. In addition, for example, the liquid supplied onto the substrate to be exposed is sucked and collected by a vacuum pump with a predetermined recovery force (negative pressure). However, when the liquid is discharged from the recovery tank, the recovery force is disturbed. May occur. If the recovery force is disturbed, the amount of liquid recovered fluctuates, causing a fluctuation in the amount of liquid supplied on the substrate to be exposed, which may also reduce the exposure accuracy.

In addition, since the amount of liquid that can be temporarily stored in the recovery tank is limited, if the amount of liquid increases, the liquid overflows from the recovery tank. Conversely, when the amount of liquid stored in the recovery tank falls below a predetermined amount, both liquid and air are discharged from the recovery tank, or only air is discharged from the recovery tank. The discharge system (pump, etc.) is adversely affected and may be damaged in some cases.

The present invention has been made in view of the above circumstances, and uses an exposure apparatus capable of appropriately discharging the collected liquid, an exposure method liquid processing method, an exposure method using the liquid processing method, and the exposure apparatus. An object of the present invention is to provide a device manufacturing method.

In order to solve the above problems, an exposure apparatus according to a first aspect of the present invention is an exposure apparatus (EX) that exposes a substrate (P) through a projection optical system (PL) and a liquid (w). A liquid recovery device (CW) for recovering the liquid supplied to the image plane side of the projection optical system to the recovery portions (41, 42, 61) via the recovery ports (36, 36a, 36b, 36a ′, 36b ′); And a control device (CS) for controlling the discharge operation of the liquid recovered by the recovery unit from the recovery unit in synchronization with the operation of the exposure apparatus (EX).
According to this invention, the liquid collected in the collection unit is discharged from the collection unit in synchronization with the operation of the exposure apparatus.
An exposure apparatus according to a second aspect of the present invention provides an image plane of the projection optical system in the exposure apparatus (EX) that exposes the substrate (P) through the projection optical system (PL) and the liquid (w). A liquid recovery apparatus (CW) for recovering the liquid supplied to the side to the recovery section (41, 42, 61) via the recovery ports (36, 36a, 36b, 36a ′, 36b ′); A control device (CS) for controlling the operation, wherein the liquid recovery device has a plurality of recovery units, and the control device controls switching of the recovery unit connected to the recovery port. .
According to the present invention, the plurality of collecting units provided are switched by the control unit, and the liquid supplied to the image plane side of the projection optical system is collected by the collecting unit connected to the collecting unit by the control device.
An exposure apparatus according to a third aspect of the present invention provides an image plane of the projection optical system in the exposure apparatus (EX) that exposes the substrate (P) through the projection optical system (PL) and the liquid (w). A liquid supply device (SW) for supplying a liquid to the side, a liquid recovery device (CW) for recovering the liquid supplied to the image plane side of the projection optical system to a recovery unit (41, 42, 61), and the recovery A liquid level detection system (51, 52, 62) for detecting the surface position of the liquid collected in the unit, and a control device for controlling the liquid supply from the liquid supply apparatus based on the detection result of the liquid level detection system ( CS).
According to the present invention, the surface position of the liquid recovered in the recovery unit provided in the liquid recovery apparatus is detected by the liquid level detection system, and the liquid supply from the liquid supply apparatus is controlled based on the detection result.

The device manufacturing method of the present invention is characterized by using any of the exposure apparatuses described above. In order to solve the above problems, a liquid processing method according to a first aspect of the present invention is a liquid processing method in an exposure apparatus (EX) that exposes a substrate (P) through a liquid (w), and is supplied. A recovery step of recovering the collected liquid in the recovery unit, and a discharge step of discharging the liquid recovered in the recovery unit from the recovery unit in synchronization with the operation of the exposure apparatus.
According to this invention, the liquid collected in the collection unit is discharged from the collection unit in synchronization with the operation of the exposure apparatus.
A liquid processing method according to the second aspect of the present invention is a liquid processing method in an exposure apparatus (EX) that exposes a substrate (P) through a liquid (w), in order to recover the supplied liquid. The recovery port (36, 36a, 36b, 36a ', 36b') and the first recovery part (41), and recovers the supplied liquid to the first recovery part; A second recovery step of connecting the mouth and a second recovery part (42) different from the first recovery part, and recovering the supplied liquid to the second recovery part; and not connected to the recovery port And a discharge step of discharging the liquid recovered by the first recovery part from the first recovery part.

According to the present invention, after the first recovery unit and the recovery port are connected and the liquid supplied onto the substrate is recovered by the first recovery unit, the second recovery unit and the recovery port different from the first recovery unit are collected. And the liquid supplied onto the substrate is recovered, and the liquid is discharged from the first recovery unit that is not connected to the recovery port.
Furthermore, the liquid processing method of the present invention is a liquid processing method in an exposure apparatus (EX) that exposes a substrate (P) through a liquid (w), the supplying step supplied onto the substrate, and the substrate The recovery step of recovering the liquid supplied above to the recovery part (41, 42, 61), and the liquid when the surface of the liquid recovered by the recovery part reaches a predetermined position (WL1, WL11) And a stop step for stopping the supply of. According to the present invention, the supply of the liquid is stopped when the surface of the liquid recovered by the recovery unit reaches a predetermined position.

The exposure method of the present invention is characterized by using any of the liquid processing methods described above.

According to the present invention, there is no adverse effect such as vibration on an operation that requires high accuracy such as pattern transfer, and thus the collected liquid can be discharged without deteriorating exposure accuracy. is there.
Further, according to the present invention, since the recovery unit communicating with the recovery port is switched, even when an operation requiring high accuracy is performed, for example, the liquid is discharged from the recovery unit not communicating with the recovery port. As a result, the collected liquid can be discharged without deteriorating the exposure accuracy.
Further, according to the present invention, since the liquid supply from the liquid supply device is controlled based on the detection result of the position of the liquid surface collected in the collection unit, for example, it is possible to prevent the liquid from overflowing from the collection unit. it can.
Furthermore, according to the present invention, it is possible to prevent deterioration in exposure accuracy caused by the discharge operation of the liquid collected in the collection unit, etc. Since the exposure apparatus that can prevent the exposure apparatus is used, a device having a desired performance with a high yield can be manufactured at a low cost.

1 is a schematic block diagram of an exposure apparatus according to a first embodiment of the present invention. It is a top view which shows an example of positional relationship with liquid projection mechanism PR of liquid supply mechanism SW and liquid collection | recovery mechanism CW, and projection optical system PL. It is a figure for demonstrating the alarm threshold value and stop threshold value which are set with respect to the collection tank 41. FIG. It is a figure which shows the structure of liquid supply mechanism SW by 2nd Embodiment of this invention, liquid collection | recovery mechanism CW, and projection optical system PL front-end | tip part vicinity. It is a figure for demonstrating the threshold value set with respect to the collection | recovery tank provided in the exposure apparatus by 2nd Embodiment of this invention. It is a flowchart which shows an example of the manufacturing process of a microdevice. It is a figure which shows an example of the detailed flow of step S13 of FIG. 6 in the case of a semiconductor device.

Explanation of symbols

  36 Recovery nozzle (recovery port) 41, 42, 61 Recovery tank (recovery unit) 51, 52, 62 Water level sensor (water level detection means) CS Main control system (control device) CW Liquid recovery mechanism (liquid recovery device) SW Liquid supply Mechanism (liquid supply device) WL1 Stop threshold (first water level) WL2 Alarm threshold (second water level) WL11 Water level (first water level) WL12 Water level (second water level) WL13 Water level (third water level) WL14 Water level (fourth water level)

  Hereinafter, an exposure apparatus, a liquid processing method, and a device manufacturing method according to embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
Hereinafter, although embodiment concerning the present invention is described, the present invention is not limited to this.
FIG. 1 is a schematic block diagram of an exposure apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the exposure apparatus EX of the present embodiment illuminates the mask stage MST holding the mask M, the substrate stage PST holding the substrate P, and the mask M held on the mask stage MST with the exposure light EL. Illumination optical system IS, projection optical system PL that projects and exposes the pattern image of the mask M illuminated by the exposure light EL onto the substrate P supported by the substrate stage PST, and a main control system that controls the overall operation of the exposure apparatus EX Consists of CS.

  In addition, the exposure apparatus EX of the present embodiment is an immersion type exposure apparatus to which an immersion method is applied in order to improve the resolution by substantially shortening the exposure wavelength and substantially increase the depth of focus. The liquid supply mechanism SW for supplying the liquid w onto the substrate P and the liquid recovery mechanism CW for recovering the liquid w on the substrate P are provided. The exposure apparatus EX performs at least one exposure on the substrate P including the projection region PR of the projection optical system PL by the liquid w supplied from the liquid supply mechanism SW during the exposure operation for transferring the pattern of the mask M onto the substrate P. A liquid immersion region WR is formed in the part. Specifically, the exposure apparatus EX fills the space between the optical element 1 at the front end (end portion) of the projection optical system PL and the surface of the substrate P with the liquid w, and masks the projection optical system PL and the liquid w through the mask. The pattern image of M is projected onto the substrate P to expose the substrate P.

  The exposure apparatus EX shown in FIG. 1 is a scanning exposure apparatus (transferring a pattern formed on the mask M onto the substrate P while moving the mask M and the substrate P in different directions (reverse directions) in the scanning direction. This is a so-called scanning stepper. In the following description, an XYZ orthogonal coordinate system is set in the drawing as needed, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The direction that coincides with the optical axis AX of the projection optical system PL is the Z-axis direction, and the synchronous movement direction (scanning direction) between the mask M and the substrate P in the plane perpendicular to the Z-axis direction is the X-axis direction, Z-axis direction, and X A direction perpendicular to the axial direction (non-scanning direction) is set as the Y-axis direction. Further, the rotation (inclination) directions around the X, Y, and Z axes are set to the θX, θY, and θZ directions, respectively. Here, the “substrate” includes a semiconductor wafer coated with a photoresist, which is a photosensitive material, and the “mask” includes a reticle on which a device pattern to be reduced and projected is formed on the substrate.

  The exposure apparatus EX includes a main column 2 that supports the mask stage MST and the projection optical system PL. The main column 2 is installed on a base plate 3 placed horizontally on the floor surface. The main column 2 is formed with an upper step 2a and a lower step 2b that protrude inward. The illumination optical system IS is supported by a support column 4 fixed to the upper part of the main column 2. The illumination optical system IS illuminates the mask M supported by the mask stage MST with the exposure light EL, and the exposure light source and the optical integrator and optical integrator for uniformizing the illuminance of the light beam emitted from the exposure light source A condenser lens that collects the exposure light EL from the light source, a relay lens system, and a variable field stop that sets the illumination area on the mask M by the exposure light EL in a slit shape. A predetermined illumination area on the mask M is illuminated with the exposure light EL having a uniform illuminance distribution by the illumination optical system IS.

  In this embodiment, it is assumed that an ArF excimer laser (wavelength 193 nm) is provided as an exposure light source. Further, as the liquid w supplied between the projection optical system PL and the substrate P, pure water that absorbs less ArF excimer laser light is used.

  The mask stage MST holds the mask M, and an opening 5a through which the pattern image of the mask M passes is formed at the center thereof. A mask surface plate 7 is supported on the upper step 2 a of the main column 2 via a vibration isolation unit 6. An opening 5 b that allows the pattern image of the mask M to pass through is also formed at the center of the mask surface plate 7. A plurality of gas bearings (air bearings) 8 which are non-contact bearings are provided on the lower surface of the mask stage MST.

  The mask stage MST is supported in a non-contact manner on the upper surface (guide surface) 7a of the mask surface plate 7 by the air bearing 8, and is perpendicular to the optical axis AX of the projection optical system PL by a mask stage driving mechanism such as a linear motor. It can move two-dimensionally in the plane, that is, the XY plane, and can rotate in the θZ direction. A movable mirror 9 is provided on the mask stage MST. A laser interferometer 10 is provided at a position facing the movable mirror 9. The position of the mask M on the mask stage MST in the two-dimensional direction and the rotation angle in the θZ direction (including rotation angles in the θX and θY directions in some cases) are measured in real time by the laser interferometer 10, and the measurement result is the main control. It is output to the system CS. The main control system CS controls the position of the mask M supported by the mask stage MST by driving the mask stage driving mechanism based on the measurement result of the laser interferometer 10.

The projection optical system PL projects the pattern image of the mask M onto the substrate P at a predetermined projection magnification β, and includes a plurality of optical elements including an optical element (lens) 1 provided at the front end portion on the substrate P side. The element is configured to be supported by a lens barrel PK. In the present embodiment, the projection optical system PL is a reduction system having a projection magnification β of, for example, 1/4, 1/5, or 1/8. Note that the projection optical system PL may be either an equal magnification system or an enlargement system. The projection optical system PL may be any of a refraction system that does not include a reflection element, a reflection system that does not include a refraction element, and a catadioptric system that includes a refraction element and a reflection element.
A flange portion FLG is provided on the outer peripheral portion of the lens barrel PK. A lens barrel surface plate 12 is supported on the lower step 2 b of the main column 2 via a vibration isolation unit 11. The projection optical system PL is supported on the lens barrel base plate 12 by engaging the flange portion FLG of the projection optical system PL with the lens barrel base plate 12.

  The optical element 1 provided at the tip of the projection optical system PL is detachably attached to the lens barrel PK. The optical element 1 with which the liquid w in the immersion area WR comes into contact is formed of meteorite. Since meteorite has high affinity with water, the liquid w can be brought into close contact with almost the entire liquid contact surface of the optical element 1. Thereby, the optical path of the exposure light EL between the optical element 1 and the substrate P can be reliably filled with the liquid w. The optical element 1 may be quartz having high affinity with pure water. Further, the liquid contact surface of the optical element 1 may be subjected to a hydrophilization (lyophilic treatment) to further increase the affinity with the liquid w.

A plate member 13 is provided around the optical element 1 so as to surround the optical element 1.
The plate member 13 is provided in order to satisfactorily form the liquid immersion region WR over a wide range, and the surface (that is, the lower surface) facing the substrate P is a flat surface. The lower surface (liquid contact surface) of the optical element 1 provided at the distal end portion of the projection optical system PL is also a flat surface, and is arranged so that the lower surface of the plate member 13 and the lower surface of the optical element 1 are substantially flush. . Similar to the optical element 1, the lower surface of the plate member 13 can be subjected to surface treatment (lyophilic treatment).

  The substrate stage PST is configured to be movable by sucking and holding the substrate P via the substrate holder 14, and a plurality of gas bearings (air bearings) 15 which are non-contact bearings are provided on the lower surface thereof. A substrate surface plate 17 is supported on the base plate 3 via a vibration isolation unit 16. The air bearing 15 is an air outlet that blows gas (air) toward the upper surface (guide surface) 17a of the substrate surface plate 17, and intake air that sucks gas between the lower surface (bearing surface) of the substrate stage PST and the guide surface 17a. And a constant gap is maintained between the lower surface of the substrate stage PST and the guide surface 17a due to the balance between the repulsive force caused by the blowing of gas from the blower outlet and the suction force caused by the intake port.

  That is, the substrate stage PST is supported by the air bearing 15 in a non-contact manner with respect to the upper surface (guide surface) 17a of the substrate surface plate (base member) 17, and the substrate stage driving mechanism such as a linear motor is used for the projection optical system PL. It can move two-dimensionally in a plane perpendicular to the optical axis AX, that is, in the XY plane, and can be rotated slightly in the θZ direction. Further, the substrate holder 14 is provided so as to be movable in the Z-axis direction, the θX direction, and the θY direction with respect to the substrate stage PST. The substrate stage drive mechanism is controlled by the main control system CS. That is, the main control system CS controls the substrate holder 14 via the substrate stage drive mechanism, and controls the focus position (Z position) and the tilt angle of the substrate P so that the surface of the substrate P is image plane of the projection optical system PL. To fit.

  A movable mirror 18 is provided on the substrate stage PST (substrate holder 14), and a laser interferometer 19 is provided at a position facing the movable mirror 18. The two-dimensional position and rotation angle of the substrate P on the substrate stage PST are measured in real time by the laser interferometer 19, and the measurement result is output to the main control system CS. The main control system CS positions the substrate P supported by the substrate stage PST by driving a substrate stage driving mechanism including a linear motor based on the measurement result of the laser interferometer 19.

  An auxiliary plate 20 is provided on the substrate stage PST (substrate holder 14) so as to surround the substrate P. The auxiliary plate 20 has a flat surface almost the same height as the surface of the substrate P held by the substrate holder 14. By providing this auxiliary plate 20, even when the edge region of the substrate P is exposed, the liquid w is held under the projection optical system PL by the auxiliary plate 20 and the substrate P. In addition, a recovery port 21 connected to a recovery device (not shown) that recovers the liquid w that has flowed out of the substrate P is provided outside the auxiliary plate 20 on the upper surface of the substrate holder 14. The recovery port 21 is an annular groove formed so as to surround the auxiliary plate 20, and a liquid absorbing member made of a sponge-like member, a porous body, or the like is disposed therein.

  The substrate stage PST is supported by the X guide stage 22 so as to be movable in the X-axis direction. The substrate stage PST is movable with a predetermined stroke in the X-axis direction by the X linear motor 23 while being guided by the X guide stage 22. At both ends in the longitudinal direction of the X guide stage 22, a pair of Y linear motors 24 that can move the X guide stage 22 along with the substrate stage PST in the Y axis direction are provided. A gas bearing (air bearing) 28 that is a non-contact bearing is interposed between the stator of the Y linear motor 24 and the flat portion of the guide portion 25, and the stator of the Y linear motor 24 is guided by the air bearing 28. Non-contact support is performed on the flat portion of the portion 25.

  Further, on both sides of the substrate surface plate 17 in the X-axis direction, guide portions 25 that are formed in an L shape in front view and guide the movement of the X guide stage 22 in the Y-axis direction are provided. The guide portion 25 is supported on the base plate 3. On the other hand, a concave guided member 26 is provided at each of both longitudinal ends of the lower surface of the X guide stage 22. The guide portion 25 engages with the guided member 26 and is provided so that the upper surface (guide surface) of the guide portion 25 and the inner surface of the guided member 26 face each other. A gas bearing (air bearing) 27, which is a non-contact bearing, is provided on the guide surface of the guide portion 25, and the X guide stage 22 is supported in a non-contact manner with respect to the guide surface.

Next, the liquid supply mechanism SW and the liquid recovery mechanism CW will be described. In the following description, the liquid w is supplied mainly on the substrate P arranged to face the projection optical system PL, but another object (for example, the auxiliary plate 20) is connected to the projection optical system PL. The same applies to the case where they face each other.
The liquid supply mechanism SW supplies the liquid w between the projection optical system PL and the substrate P, and includes an ultrapure water production apparatus 30, a temperature adjustment apparatus 31, and a supply nozzle 32. The ultrapure water production apparatus 30 is an apparatus that produces ultrapure water with high purity. The temperature control device 31 includes a temperature control unit that controls the temperature of the ultrapure water produced by the ultrapure water production device 30 at a constant level, a deaeration unit that degass the ultrapure water, and temperature control and deaerated ultrapure water And a pressure pump for delivering ultrapure water. The supply nozzle 32 is arranged close to the surface of the substrate P and is connected to the temperature adjustment device 31 via the supply pipe 33, and the ultrapure water delivered from the temperature adjustment device 31 is projected as the liquid w. It is supplied between the optical system PL and the substrate P. Note that the ultrapure water production apparatus 30 and the temperature control apparatus 31 do not necessarily have to be provided in the liquid supply mechanism SW of the exposure apparatus EX, and use equipment such as a factory in which the exposure apparatus EX is set instead of at least one of them. May be.

  In the middle of the supply pipe 33, a flow meter 34 for measuring the amount of liquid w (liquid supply amount per unit time) supplied from the temperature control device 31 onto the substrate P is provided. The flow meter 34 monitors the amount of the liquid w supplied onto the substrate P and outputs the measurement result to the main control system CS. The main control system CS controls the liquid supply operation of the temperature adjustment device 31 according to the monitoring result of the flow meter 34, and controls the supply amount of the liquid w per unit time supplied between the projection optical system PL and the substrate P. To do. Further, a valve 35 that opens and closes the flow path of the supply pipe 33 is provided between the flow meter 34 and the supply nozzle 32 in the supply pipe 33. The opening / closing operation of the valve 35 is controlled by the main control system CS. The valve 35 in the present embodiment is a so-called normal-off method that mechanically closes the flow path of the supply pipe 33 when the power supply of the exposure apparatus EX (main control system CS) is shut off due to, for example, a power failure. Yes.

  The liquid recovery mechanism CW recovers the liquid w on the substrate P supplied by the liquid supply mechanism SW, and includes a recovery nozzle 36, vacuum systems 38 and 39, a flow meter 40, recovery tanks 41 and 42, and the like. Consists of including. The collection nozzle 36 is disposed in the vicinity of the surface of the substrate P and is connected to the collection tanks 41 and 42 via the collection pipe 43. The vacuum systems 38 and 39 include a vacuum pump, and the operation is controlled by the main control system CS. By driving the vacuum systems 38 and 39, the liquid w on the substrate P is recovered through the recovery nozzle 36. In the present embodiment, the recovery nozzle 36 is configured to recover only the liquid w. However, the liquid w may be recovered together with the surrounding gas (air). In that case, it is desirable to provide a separator for separating the recovered liquid w and gas in the liquid recovery mechanism CW so that only the gas is sucked into the vacuum systems 38 and 39. Further, as the vacuum systems 38 and 39, a vacuum system in a factory where the exposure apparatus EX is disposed may be used without providing a vacuum pump in the exposure apparatus.

The liquid w recovered by the recovery nozzle 36 is guided to the second recovery pipe 44 through the recovery pipe 43.
The second collection pipe 44 is branched into two collection pipes 44 a and 44 b, one collection pipe 44 a is connected to the collection tank 41, and the other collection pipe 44 b is connected to the collection tank 42. In the middle of the second recovery pipe 44, a flow meter 40 for measuring the amount of the recovered liquid w (the amount of liquid recovered per unit time) is provided. The flow meter 40 monitors the amount of the liquid w collected from the substrate P through the collection nozzle 36 and outputs the measurement result to the main control system CS.

  The main control system CS controls the operation of the vacuum system 38 or the vacuum system 39 in accordance with the monitoring result of the flow meter 40, and the liquid w recovered from the projection optical system PL and the substrate P through the recovery nozzle 36. Control the amount collected per unit time. Each of the collection pipes 44a and 44b is provided with valves 45 and 46 for opening and closing the flow paths of the collection pipes 44a and 44b, respectively. The opening and closing operations of the valves 45 and 46 are controlled by the main control system CS. The recovery tanks 41 and 42 temporarily store the liquid w recovered via the recovery nozzle 36, and discharge pipes 47 and 48 for discharging the stored liquid w are provided at the bottoms thereof. Each of the discharge pipes 47 and 48 is provided with valves 49 and 50 for opening and closing the flow paths of the discharge pipes 47 and 48, respectively. The discharge operation (discharge amount) of the valves 49 and 50 is controlled by the main control system CS so that the liquid amount (water level) in the recovery tanks 41 and 42 is suppressed to a certain level (for example, 30% of the total amount of the tank) or less. It has become. The liquid w discharged from the discharge pipes 47 and 48 is discarded or cleaned, for example, and returned to the ultrapure water production apparatus 30 or the like for reuse.

  Here, the configuration of the liquid supply mechanism SW and the liquid recovery mechanism CW will be described in detail. FIG. 2 is a plan view showing an example of the positional relationship between the liquid supply mechanism SW and the liquid recovery mechanism CW and the projection region PR of the projection optical system PL. As shown in FIG. 2, the projection region PR of the projection optical system PL has a rectangular shape (slit shape) elongated in the Y-axis direction, and three supplies are provided on the + X side so as to sandwich the projection region PR in the X-axis direction. Nozzles 32a to 32c are arranged, and two recovery nozzles 36a and 36b are arranged on the −X side. The supply nozzles 32 a to 32 c are connected to the temperature control device 31 via the supply pipe 33, and the recovery nozzles 36 a and 36 b are connected to the flow meter 40 via the recovery pipe 43.

Further, supply nozzles 32a 'to 32c' are arranged at positions symmetrical to the supply nozzles 32a to 32c with respect to the projection area PR, and collection nozzles 36a 'and 36b' are arranged at positions symmetrical to the collection nozzles 36a and 36b with respect to the projection area PR. Has been. The supply nozzles 32a to 32c and the collection nozzles 36a 'and 36b' are alternately arranged in the Y axis direction, and the supply nozzles 32a 'to 32c' and the collection nozzles 36a and 36b are arranged alternately in the Y axis direction. The supply nozzles 32 a ′ to 32 c ′ are connected to the temperature control device 31 via a supply pipe 33 ′, and the recovery nozzles 36 a ′ and 36 b ′ are connected to the flow meter 40 via a recovery pipe 43. In the middle of the supply pipe 33 ′, a flow meter 34 ′ and a valve 35 ′ are provided in the same manner as the supply pipe 33.
The configuration and arrangement of the supply nozzle and the recovery nozzle are not limited to those described above, and any configuration is possible as long as the optical path space on the image plane side of the projection optical system PL can be filled with liquid. May be. The configuration for filling the optical path space on the image plane side of the projection optical system PL with a liquid is disclosed in, for example, a mechanism disclosed in International Publication No. 2004/053955 pamphlet or European Patent Publication No. 1420298. To the extent permitted by national legislation in the designated country (or selected selected country) designated in the international application, the disclosure of each of the above publications and corresponding US patents or US patent application publications is incorporated herein by reference. Part of the description.

  Returning to FIG. 1, the recovery tanks 41, 42 are provided with water level sensors 51, 52 that detect the water level of the liquid w stored inside (the surface position of the liquid w). The water level sensors 51 and 52 constantly monitor the water level of the liquid w stored in the recovery tanks 41 and 42, respectively, and output the detection result to the main control system CS. In the main control system CS, an alarm threshold value for issuing an alarm when the water level in the recovery tanks 41 and 42 is equal to or higher than a predetermined water level, and the overflow of the liquid w from the recovery tanks 41 and 42 are prevented. A stop threshold value for stopping the supply of the liquid w is stored in advance.

  FIG. 3 is a diagram for explaining an alarm threshold value and a stop threshold value set for the collection tank 41. Here, the recovery tank 41 is described as an example, but the alarm threshold and the stop threshold are similarly set for the recovery tank 42 as well. In FIG. 3, the imaginary line with the symbol WL1 indicates the water level corresponding to the stop threshold, and the imaginary line with the symbol WL2 indicates the water level corresponding to the alarm threshold. As shown in FIG. 3, the water level WL1 corresponding to the stop threshold is set to be higher than the water level WL2 corresponding to the alarm threshold. That is, the stop threshold is set to a value larger than the alarm threshold.

  The stop threshold value is set to a value that can recover all remaining liquid w when the liquid supply operation of the temperature control device 31 is stopped and the supply of the liquid w is stopped by closing the valve 35 (35 ′). Is done. That is, the stop threshold for the recovery tank 41 is the liquid w in the flow path from the valve 35 to the supply nozzles 32a to 32c, the liquid w in the flow path from the valve 35 'to the supply nozzles 32a' to 32c ', and the substrate P. The upper liquid w and the liquid w in the flow path from the recovery nozzles 36a, 36b, 36a ′, 36b ′ to the recovery tank 41 are set to values that can be recovered in the recovery tank 41. The size of the recovery tank may be determined so that the stop threshold value can be set to about 80% of the recoverable amount of the recovery tank 41.

  Returning to FIG. 1, the main control system CS always determines whether or not the detection result of the water level sensors 51 and 52 exceeds the alarm threshold value or the stop threshold value, and the liquid supply operation of the temperature adjustment device 31 according to the determination result. It controls the opening and closing of the valves 35 and 35 ', the operation of the vacuum systems 38 and 39, the opening and closing of the valves 49 and 50, and the signal output to the alarm device KD. Here, the warning device KD is a device that issues a warning in response to a signal output from the main control system CS, and is, for example, a warning light, an alarm sound, a display, or the like. When an alarm is issued by the alarm device KD, for example, the operator can know that an abnormality has occurred in the recovery tanks 41 and 42 before the liquid w overflows from the recovery tanks 41 and 42.

  Further, the main control system CS performs control to switch between opening and closing of the valves 45 and 46 provided in the collection tubes 44a and 44b in synchronization with the operation of the exposure apparatus EX. That is, when recovering the liquid w in the recovery tank 41, the valve 45 is opened and the valve 46 is closed to connect the recovery tank 41 to the recovery nozzle 36, and when recovering the liquid w in the recovery tank 42. The valve 46 is opened and the valve 45 is closed.

  The two recovery tanks 41 and 42 are provided, and the above switching control is performed for the following reason. That is, when the liquid w stored in the recovery tank connected to the recovery nozzle 36 (36a, 36b, 36a ', 36b') is discharged, vibration is generated as the liquid w is discharged, or the vacuum system Since the recovery force (negative pressure) of 38 (or 39) is disturbed, the amount of liquid on the image plane side of the projection optical system PL may fluctuate, which may cause shortage of liquid w, leakage of liquid w, and the like. It is. Transfer of the pattern formed on the mask M onto the substrate P (exposure of the substrate P), or detection of the position of the surface of the substrate P using a focus detection system described later, or the mark formed on the substrate P using an alignment sensor If vibration occurs or fluctuations in the amount of the liquid w occur during position measurement or the like, the final exposure accuracy (resolution, transfer fidelity, overlay accuracy, etc.) may be reduced. . In the present embodiment, from the viewpoint of preventing this, it is configured to have two recovery tanks, and a recovery tank that recovers the liquid w without discharging the liquid stored in the interior is connected to the recovery nozzle 36, and the inside Control is performed to separate the recovery tank that discharges the stored liquid from the recovery nozzle 36, that is, to close the flow path to the recovery tank that discharges the liquid.

The exposure apparatus EX also includes a focus detection system that detects the position of the surface of the substrate P supported by the substrate stage PST. The focus detection system includes a light projecting unit that projects a detection light beam on the substrate P from an oblique direction via the liquid w, and a light receiving unit that receives the reflected light of the detection light beam reflected by the substrate P. . The light reception result of the focus detection system (light receiving unit) is output to the main control system CS. The main control system CS can detect the position information of the surface of the substrate P in the Z-axis direction and the tilt information of the substrate P in the θX and θY directions based on the detection result of the focus detection system.
As the configuration of the focus detection system, for example, the one disclosed in JP-A-8-37147 can be applied. The focus detection system may project the detection light beam onto the substrate P without using the liquid w.

  Further, the exposure apparatus EX includes an off-axis type alignment sensor on the side of the projection optical system PL. This alignment sensor is an FIA (Field Image Alignment) type alignment sensor, and is obtained from the substrate P by, for example, irradiating a mark formed on the substrate P with a broadband light beam emitted from a halogen lamp as a detection beam. The reflected light is imaged by an image sensor such as a CCD (Charge Coupled Device), and the captured image signal is supplied to the main control system CS. The main control system CS performs image processing on the image signal and calculates position information of the captured mark. As this alignment sensor, for example, one disclosed in JP-A-4-65603 can be applied.

  As shown in the partial sectional view of FIG. 1, the liquid supply mechanism SW and the liquid recovery mechanism CW are separated and supported with respect to the lens barrel surface plate 12. Thereby, the vibration generated by the liquid supply mechanism SW and the liquid recovery mechanism CW is not transmitted to the projection optical system PL via the lens barrel surface plate 12.

  Next, a procedure for transferring the pattern of the mask M onto the substrate P using the exposure apparatus EX configured as described above will be described. When the exposure sequence is started, the mask M is loaded on the mask stage MST and the substrate P is loaded on the substrate stage PST. Next, the position information of the marks formed on the substrate P loaded on the substrate stage PST is measured using the alignment sensor, and the main control system CS performs EGA (Enhanced Global Alignment) calculation based on the measurement result. Then, the regularity of the arrangement of all shot areas set on the substrate P is determined. Here, the EGA calculation refers to position information of marks (alignment marks) formed on each of a part of typical (3 to 9) shot areas preset on the substrate P, An arithmetic method that determines the regularity of the arrangement of all shot regions set on the substrate P based on the design information by a statistical method.

  Next, the main control system CS controls the opening and closing of the valves 45 and 46 provided in the recovery pipes 44a and 44b. Here, it is assumed that the valve 45 is opened and the valve 46 is closed, and only the collection tank 41 communicates with the collection nozzle 36 (collection nozzles 36a, 36b, 36a ′, 36b ′). When the control of the valves 45 and 46 is finished, the main control system CS outputs a control signal to the temperature control device 31 provided in the liquid supply mechanism SW, and the ultrapure water produced by the ultrapure water production device 30. While keeping the temperature constant, ultrapure water with a constant temperature is sent at a rate of a predetermined amount per unit time. The ultrapure water delivered from the temperature control device 31 is connected to the optical element 1 at the tip of the projection optical system PL via the supply pipe 33 (33 ') and the supply nozzle 32 (32a to 32c, 32a' to 32c '). A liquid w is supplied between the substrate P and the substrate P.

  The main control system CS drives the vacuum system 38 of the liquid recovery mechanism CW in accordance with the supply of the liquid w by the liquid supply mechanism SW, the recovery nozzle 36 (36a, 36b, 36a ′, 36b ′), and the recovery pipe 43. A predetermined amount of liquid w per unit time is recovered in the recovery tank 41 through the second recovery pipe 44 and the recovery pipe 44a. Thereby, an immersion region WR of the liquid w is formed between the optical element 1 at the tip of the projection optical system PL and the substrate P. Here, in order to form the liquid immersion region WR, the main control system CS, for example, sets the liquid supply mechanism SW so that the liquid supply amount on the substrate P and the liquid recovery amount from the substrate P are substantially the same. And the liquid recovery mechanism CW.

  In a state where a fixed amount of liquid w is constantly supplied between the projection optical system PL and the substrate P (the optical path space on the image plane side of the projection optical system PL is filled with the liquid w), the main control system CS emits exposure light EL from illumination optical system IS to illuminate mask M, and projects an image of the pattern of mask M onto substrate P via projection optical system PL and liquid w. During the scanning exposure, a part of the pattern image of the mask M is projected onto the projection region PR, and in synchronization with the movement of the mask M in the −X direction (or + X direction) at the speed V with respect to the projection optical system PL. The substrate P moves in the + X direction (or -X direction) at a speed β · V (β is the projection magnification). When the scanning exposure for one shot area is completed, the main control system CS moves the substrate stage PST by stepping to move the next shot area to the scanning start position. Similarly, the step-and-scan method applies to each shot area. Exposure processing is performed sequentially.

In the present embodiment, the liquid w is set to flow in the same direction as the movement direction of the substrate P.
That is, when scanning exposure is performed by moving the substrate P in the scanning direction SD1 (−X direction) in FIG. 2, the supply pipe 33, the supply nozzles 32a to 32c, the collection nozzles 36a and 36b, and the collection pipe 43 are provided. The liquid w is supplied and recovered by the liquid supply mechanism SW and the liquid recovery mechanism CW. That is, when the substrate P moves in the −X direction, the liquid w is supplied from the supply nozzle 32 (32a to 32c) between the projection optical system PL and the substrate P, and the liquid w on the substrate P is The liquid w is collected from the collection nozzle 36 together with the surrounding gas, and the liquid w flows in the −X direction so as to fill between the optical element 1 and the substrate P at the tip of the projection optical system PL.

  On the other hand, when scanning exposure is performed by moving the substrate P in the scanning direction SD2 (+ X direction) in FIG. 2, the supply pipe 33 ′, the supply nozzles 32a ′ to 32c ′, the recovery nozzles 36a ′, 36b ′, The liquid w is supplied and recovered by the liquid supply mechanism SW and the liquid recovery mechanism CW using the recovery pipe 43. That is, when the substrate P moves in the + X direction, the liquid w is supplied between the projection optical system PL and the substrate P from the supply nozzle 32 '(32a' to 32c '), and the liquid on the substrate P is also supplied. The w is recovered from the recovery nozzle 36 together with the surrounding gas, whereby the liquid w flows in the + X direction so as to fill the space between the optical element 1 at the tip of the projection optical system PL and the substrate P.

  By supplying the liquid w using the above method, for example, the liquid w supplied via the supply nozzles 32a to 32c is moved between the optical element 1 and the substrate P as the substrate P moves in the −X direction. Therefore, even if the supply energy of the liquid supply mechanism SW (temperature control device 31) is small, the liquid w can be easily supplied between the optical element 1 and the substrate P. By switching the direction (supply nozzle) in which the liquid w flows according to the scanning direction, the substrate 1 is sufficiently spaced between the optical element 1 and the substrate P when scanning the substrate P in either the + X direction or the −X direction. Can be filled with liquid w.

  In the exposure process or the like, while the liquid w is supplied from the supply nozzle 32 of the liquid supply mechanism SW, the measurement result of the flow meter 34 (34 ′) provided in the liquid supply mechanism SW and the liquid recovery mechanism CW. The measurement result of the flow meter 40 provided in is output to the main control system CS. The main control system CS measures the measurement result of the flow meter 34 (34 '), that is, the amount of liquid supplied onto the substrate P via the supply nozzle 32 of the liquid supply mechanism SW, and the measurement result of the flow meter 40, that is, liquid. The amount of liquid recovered from the substrate P through the recovery nozzle 36 of the recovery mechanism CW is compared, and the valve 35 (35 ′) of the liquid supply mechanism SW is controlled based on the comparison result.

  Specifically, the main control system CS determines the liquid supply amount (measurement result of the flow meter 34 (34 ′)) on the substrate P and the liquid recovery amount (measurement result of the flow meter 40) from the substrate P. A difference is obtained, and the valve 35 (35 ') is controlled based on whether or not the obtained difference exceeds a preset allowable value (threshold value). In the present embodiment, as described above, the main control system CS allows the liquid supply mechanism SW and the liquid recovery mechanism CW so that the liquid supply amount on the substrate P and the liquid recovery amount from the substrate P are substantially the same. Therefore, if the liquid supply operation by the liquid supply mechanism SW and the liquid recovery operation by the liquid recovery mechanism CW are normally performed, the difference obtained as described above is almost zero.

When the calculated difference is greater than or equal to the allowable value, that is, when the liquid recovery amount is extremely small compared to the liquid supply amount, the main control system CS generates an abnormality in the recovery operation of the liquid recovery mechanism CW and sufficiently supplies the liquid w. Judge that it is not collected. At this time, the main control system CS determines that an abnormality such as a failure has occurred in the vacuum system 38 (39) of the liquid recovery mechanism CW, for example, and the liquid w caused by the liquid recovery mechanism CW being unable to recover the liquid w normally. In order to prevent leakage of the liquid, the valve 35 (35 ′) of the liquid supply mechanism SW is operated to shut off the flow path of the supply pipe 33 (33 ′), and the liquid w is supplied onto the substrate P by the liquid supply mechanism SW. To stop. As described above, the main control system CS compares the amount of the liquid w supplied onto the substrate P from the liquid supply mechanism SW with the amount of the liquid w recovered by the liquid recovery mechanism CW, and based on the comparison result. Then, an abnormality in the recovery operation of the liquid recovery mechanism CW is detected, and the supply of the liquid w onto the substrate P is stopped when the supply of the liquid w becomes excessive and an abnormality is detected. Thereby, the leakage of the liquid w to the outside of the substrate P and the substrate stage PST, the penetration of the liquid w into an undesired location, or the spread of damage due to such leakage or penetration can be prevented.
When the liquid supply amount is extremely small compared to the liquid recovery amount, it is determined that an abnormality has occurred in the supply operation of the liquid supply mechanism SW, and the supply pipe 33 is operated by operating the valve 35 (35 ′) of the liquid supply mechanism SW. The channel (33 ′) may be blocked.

  The liquid w guided from the recovery pipe 43 to the second recovery pipe 44 is temporarily stored in the recovery tank 41 via the recovery pipe 44a. When the exposure process for all the shot areas set on the substrate P is completed, the main control system CS stops the liquid supply operation of the temperature adjustment device 31 and performs only the recovery operation of the liquid w by the liquid recovery mechanism CW. Then, the liquid w on the substrate P and the liquid w between the recovery nozzle 36 and the recovery tank 41 are recovered in the recovery tank 41.

  When the recovery operation ends, the main control system CS performs control to switch between opening and closing of the valves 45 and 46 after stopping the liquid recovery operation of the liquid recovery mechanism CW. That is, the valve 45 is closed and the valve 46 is opened. As a result, only the recovery tank 42 communicates with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′). During the switching of the valves 45 and 46, the substrate P on the substrate stage PST is unloaded and a new substrate P is loaded on the substrate stage PST. When a new substrate P is loaded, the main control system CS restarts the liquid supply operation by the liquid supply mechanism SW and the liquid recovery operation by the liquid recovery mechanism CW, and starts the exposure process in the same procedure as described above. .

  When the switching control of the valves 45 and 46 is completed, the main control system CS opens the valve 49 in parallel with the exposure process and opens the collection nozzle 36 (collection nozzles 36a, 36b, 36a ′, 36b ′). The liquid w stored in the collection tank 41 that is not in communication is discharged. In this case, since the valve 45 provided in the recovery pipe 44a connected to the recovery tank 41 is closed, the vibration accompanying the discharge of the liquid w and the recovery force (negative pressure) of the vacuum system 39 are not disturbed. Thereby, the deterioration of the exposure accuracy resulting from the vibration or the change in the liquid amount of the liquid w can be suppressed.

  When the operation of discharging the liquid w from the recovery tank 41 is completed and the exposure processing for all shot regions set on the substrate P on the substrate stage PST is completed, the main control system CS again performs the liquid supply operation of the temperature adjustment device 31. And the liquid w remaining on the substrate P and the like are recovered and the liquid recovery operation of the liquid recovery mechanism CW is stopped. Thereafter, the valves 45 and 46 are opened and closed to control the valve 45 to be opened and the valve 46 closed, and only the recovery tank 41 communicates with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′). To the state. Further, during the switching of the valves 45 and 46, the substrate P is unloaded and a new substrate P is loaded. Further, in parallel with the exposure operation of the exposure apparatus EX, the valve 50 is opened to discharge the liquid w stored in the recovery tank 42 not communicating with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′). Let When the above operation is completed, the exposure process for the substrate P on the substrate stage PST is performed again, and the above-described operation is repeated for the exposure process for a plurality of substrates P.

The detection results of the water level sensors 51 and 52 provided in the recovery tanks 41 and 42 are always output to the main control system CS. The main control system CS compares the detection results of the water level sensors 51 and 52 with preset alarm threshold values and stop threshold values, and determines whether each detection result exceeds the alarm threshold value or the stop threshold value. . For example, when it is determined that the water level of the recovery tank 42 communicating with the recovery nozzle 36 exceeds the alarm threshold during the exposure of the substrate P, the main control system CS outputs a signal to switch the alarm device KD. To drive. When a signal is output from the main control system CS, an alarm is issued from the alarm device KD by a warning light, alarm sound, display, or the like. Thereby, it is possible to notify an operator or the like that there is a possibility that the liquid w may overflow from the recovery tanks 41 and 42, or that an abnormality has occurred in the liquid supply mechanism SW or the liquid recovery mechanism CW of the exposure apparatus EX.

  For example, when the water level in the recovery tank 42 reaches the alarm threshold, the main control system CS continues the exposure process until the exposure process for the shot area being exposed, the wafer being exposed, or the lot being exposed is completed. Thereafter, the valve 50 is opened, the exposure process is interrupted, and the stored liquid w is discharged from the recovery tank 42. Note that at what point the exposure process is continued and interrupted depends on the size of the recovery tanks 41 and 42 (recovery capability), the set value of the alarm threshold, the recovery amount of the liquid w per unit time, and the like. You only have to set it.

  Further, during the exposure of the substrate P, for example, when the water level of the recovery tank 42 communicating with the recovery nozzle 36 reaches the stop threshold, the main control system CS immediately interrupts the exposure operation, and the temperature adjustment device 31. The liquid supply operation is stopped and the valve 35 (35 ') is closed to stop the supply of the liquid w, and the substrate stage PST is stopped under the projection optical system PL. Then, the liquid w on the substrate P and the liquid w between the recovery nozzle 36 and the recovery tank 42 are recovered, and the valve 50 is opened to discharge the liquid w from the recovery tank 42. In this case, it goes without saying that the discharge of the liquid w from the recovery tank 41 may be performed in parallel. As described above, since the stop threshold value is set to a value that allows recovery of the remaining liquid w or more, from the time when it is determined that the water level of any of the recovery tanks 41 and 42 exceeds the stop threshold value. Even if the above liquid w is collected, the liquid w does not overflow from the collection tanks 41 and 42.

  As described above, in the present embodiment, by switching the valves 45 and 46, the recovery tanks 41 and 42 communicating with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′) are switched, and the recovery nozzle 36 is switched. Since the liquid w is discharged from a recovery tank that does not communicate with the (recovery nozzles 36a, 36b, 36a ′, 36b ′), that is, a recovery tank that does not recover the liquid w, vibration and vacuum accompanying the discharge of the liquid w Variations in the recovery force (negative pressure) of the system 38 or 39 can be suppressed. Therefore, for example, the vibration associated with the discharge of the liquid w does not affect an operation that requires a high alignment accuracy such as measurement of mark position information by the alignment sensor or transfer of the pattern of the mask M. The fluctuation of the liquid w supplied on the substrate P (change in refractive index due to vibration, change in liquid amount) is not caused, and exposure accuracy is not deteriorated.

  Further, the water level of the liquid accumulated in the recovery tank (41 or 42) communicating with the recovery nozzle 36 is monitored, and the liquid supply from the liquid supply mechanism SW is stopped and the recovery is performed when a predetermined threshold value is reached. Since the liquid discharging operation of the recovery tank communicating with the nozzle 36 is performed, it is possible to prevent the liquid from overflowing from the recovery tank (41 or 42). When the water level of the recovery tank (41 or 42) communicating with the recovery nozzle 36 reaches the stop threshold, the valve (45 or 46) is immediately closed to stop the recovery of the liquid w on the substrate P. The liquid discharging operation of the recovery tank that has been in communication with the recovery nozzle 36 may be performed.

In the above-described embodiment, the switching control of the valves 45 and 46 is performed every time the exposure process on the substrate P is completed in synchronization with the operation of the exposure apparatus EX. However, the valve is controlled according to the exposure process sequence and the recovery tank capacity. It is desirable to change the switching control to 45 and 46. For example, when the number of shots set on the substrate P is large, the switching control of the valves 45 and 46 is performed every time exposure processing for a predetermined number of shots is completed, and the number of shots set on one substrate P is determined. When the number is small, the switching control of the valves 45 and 46 may be performed every time a plurality of sheets or lots are exposed.
In the above-described embodiment, the second recovery pipe 44 is branched into the recovery pipe 44a and the recovery pipe 44b, and each is connected to the recovery tanks 41 and 42 via valves 45 and 46, respectively. However, the recovery pipe that forms the flow path from the recovery nozzles 36a and 36b to the recovery tank 41 and the recovery pipe that forms the flow path from the recovery nozzles 36a 'and 36b' to the recovery tank 42 are arranged separately. For example, when the substrate P moves in the −X direction, the liquid w collected from the collection nozzles 36a and 36b is caused to flow to the collection tank 41. When the substrate P moves in the + X direction, the liquid collected from the collection nozzles 36a ′ and 36b ′. You may make it flow w to the collection tank 42. In this case, the liquid w can be discharged from the collection tank 41 when the substrate P moves in the + X direction, and the liquid w can be discharged from the collection tank 42 when the substrate P moves in the −X direction.

  The liquid discharging operation from the recovery tank (41 or 42) not communicating with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ', 36b') is performed by measuring the mark on the substrate P using the alignment sensor and masking. It goes without saying that it is preferable to avoid as much as possible while performing an operation that requires high accuracy, such as during transfer of the M pattern. That is, the discharge operation of the liquid w from the collection tank (41 or 42) not communicating with the collection nozzle 36 is performed when, for example, the mark measurement of the substrate P using the alignment sensor is not performed, or the pattern of the mask M is transferred. More specifically, when loading or unloading the substrate P (during replacement of the substrate P), the EGA calculation is started after the alignment mark is detected and the pattern transfer of the mask M is started. It is desirable to perform in synchronization with the operation of the exposure apparatus during the period of time or at a timing such as a processing preparation period of a lot consisting of a plurality of substrates P. By discharging the liquid w from the collection tank at such timing, it is possible to more reliably prevent adverse effects on operations that require high accuracy such as pattern transfer. In the above-described embodiment, two recovery tanks are switched and used. However, three or more recovery tanks may be provided and switched as appropriate.

[Second Embodiment]
Next, an exposure apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is an excerpt of the main part from the exposure apparatus EX of FIG. The exposure apparatus of the present embodiment is substantially the same in overall configuration as the exposure apparatus according to the first embodiment of the present invention described above, but has one collection tank and the water level set for the collection tank. The threshold is different. That is, in the second embodiment, the vacuum system 39, the recovery tank 42, the recovery pipe 44b, the discharge pipe 48, the valve 50, the water level sensor 52, and the connection between these and the main control system CS are omitted. Further, in the present embodiment, one recovery tank 61 is provided instead of the recovery tank 41 shown in FIG. Other configurations are the same as those in FIG.

  FIG. 5 is a view for explaining thresholds set for the collection tank 61 provided in the exposure apparatus according to the second embodiment of the present invention. The configuration of the recovery tank 61 shown in FIG. 5 is almost the same as that of the recovery tank 41 shown in FIG. That is, a water level sensor 62 is provided inside the recovery tank 61, and the detection result of the water level sensor 62 is output to the main control system CS. A discharge pipe 63 for discharging the liquid w stored in the recovery tank 61 is provided at the bottom, and a valve 64 for opening and closing the flow path of the discharge pipe 63 is provided in the discharge pipe 63. The opening / closing operation of the valve 64 is controlled by the main control system CS. The liquid w discharged from the discharge pipe 63 is discarded or cleaned, for example, and returned to the ultrapure water production apparatus 30 or the like for reuse.

  In the present embodiment, four threshold values of first to fourth threshold values are set for the water level detected by the water level sensor 62 in the main control system CS. In FIG. 5, the imaginary line with the reference WL11 corresponds to the water level corresponding to the first threshold, the imaginary line with the reference WL12 corresponds to the water level corresponding to the second threshold, and the imaginary line with the reference WL13 corresponds to the third threshold. The imaginary line with the water level and the symbol WL14 is the water level corresponding to the fourth threshold value. The water level WL11 is the same as the water level set for the stop threshold shown in FIG. 3, and the water level WL12 is the same as the water level set for the alarm threshold shown in FIG. In other words, when the water level of the recovery tank 61 is higher than the water level WL12, a signal is output from the main control system CS to the alarm device KD and an alarm is issued from the alarm device KD, and when the water level is higher than the water level WL11, the liquid w from the liquid supply mechanism SW The supply is stopped and the liquid w is collected. Note that the water level WL11 can recover all of the liquid w and the like remaining on the substrate P in the recovery tank 61 after the supply of the liquid w is stopped, similarly to WL1 set in the first embodiment. The water level is set. Preferably, the water level WL11 is set to about 80% of the recovery capacity of the recovery tank 61.

  The water level WL13 is set to a lower water level than the water level WL12, and the water level WL14 is set to a lower water level than the water level WL13. The third threshold value set for the water level WL13 is a threshold value used for performing control so that a predetermined amount or more of the liquid w is stored in the recovery tank 61. That is, the main control system CS controls the valve 64 so that the water level of the liquid w stored in the recovery tank 61 is maintained between the water level WL12 and the water level WL13 as much as possible. The fourth threshold value set for the water level WL14 is a threshold value that determines the minimum amount of the liquid w stored in the recovery tank 61. If the liquid w in the recovery tank 61 falls below a predetermined amount, gas is discharged from the recovery tank 61 together with the liquid w, or only the gas is discharged, which may adversely affect the discharge system. Thus, even if the water level of the liquid w in the recovery tank 61 is lower than the water level WL13 corresponding to the third threshold value, the fourth threshold value is set to ensure the minimum amount of water.

  In the above configuration, the transfer of the pattern of the mask M to the substrate P is performed in the same procedure as in the first embodiment described above. That is, the mask M is loaded on the mask stage MST and the substrate P is loaded on the substrate stage PST, and the position information of the marks formed on the substrate P is measured using the alignment sensor, and the EGA calculation is performed. The regularity of the arrangement of shot areas on the substrate P is determined. Next, the valve 45 provided in the recovery pipe 44a is opened, and the recovery tank 61 is communicated with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′). In the present embodiment, the valve 45 may be left open, that is, the recovery nozzle 36 and the recovery tank 61 may be kept in communication.

  Next, the optical element 1 and the substrate P provided at the tip of the projection optical system PL through the supply pipes 33 and 33 'and the supply nozzles 32 (32a to 32c, 32a' to 32c ') by driving the liquid supply mechanism SW. And the liquid supply mechanism SW is driven to supply the liquid w supplied onto the substrate P via the recovery nozzle 36 (36a, 36b, 36a ′, 36b ′) to the recovery tank 61. To be recovered. The mask stage MST and the substrate stage PST are scanned while the fixed amount of liquid w is constantly supplied between the projection optical system PL and the substrate P, the mask M is illuminated by the exposure light EL, and the mask An image of the M pattern is projected onto the substrate P via the projection optical system PL and the liquid w. Thereafter, similarly, exposure processing for each shot area is sequentially performed by the step-and-scan method.

  When the exposure of all the shot areas of the substrate P is completed, the liquid w supplied onto the substrate P passes through the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′) as in the first embodiment. Thus, the fuel is recovered in the recovery tank 61 that communicates with the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ′, 36b ′).

  When the recovery of the liquid w on the substrate P is completed, the substrate P is replaced, that is, the exposed substrate is unloaded and the next exposed substrate is loaded. In synchronization with the operation of the exposure apparatus EX, the liquid w is discharged from the collection tank 61 during the replacement of the substrate. That is, the main control system CS opens the valve 64 and discharges the liquid w until the detection result of the water level sensor 62 indicates the water level WL13. When the detection result of the water level sensor 62 becomes the water level WL13, the main control system CS closes the valve 64 and ends the operation of discharging the liquid w from the recovery tank 61. When the substrate replacement operation and the liquid discharge operation of the collection tank 61 are finished, the main control system CS starts supplying the liquid w onto the substrate P, and in the same manner as described above, the main control system CS applies to a plurality of shot areas on the substrate P. The exposure process is sequentially executed. In the same manner, immersion exposure processing is performed on a plurality of substrates, and during the substrate replacement operation, the liquid discharge operation of the recovery tank 61 is performed in parallel with the operation.

  The detection result of the water level sensor 62 provided in the recovery tank 61 is always output to the main control system CS, and the main control system CS includes the detection result of the water level sensor 62 and preset first to fourth threshold values. To determine whether the detection result exceeds the first to fourth thresholds. If it is determined that the water level in the recovery tank 61 exceeds the second threshold value, the main control system CS outputs a signal to drive the alarm device KD as in the first embodiment. Thereby, a warning is emitted from the warning device KD by a warning light, an alarm sound, a display or the like.

  When an alarm is issued, the exposure process is continued until the exposure process for the shot area being exposed, the wafer being exposed, or the lot being exposed is completed, and then the exposure process is interrupted and the recovery tank 61 is stopped. The stored liquid w is discharged. The discharge of the liquid w is controlled so that the water level of the liquid w in the recovery tank 61 does not fall below the water level WL13 corresponding to the third threshold value. In this way, the water level of the liquid w in the recovery tank 61 is maintained between the water level WL12 and the water level WL13. Note that the point at which the exposure process is continued and interrupted is set according to the size of the recovery tank 61 (recovery capability), the set value of the second threshold, the recovery amount of the liquid w per unit time, and the like. do it.

  When it is determined that the water level in the recovery tank 61 has exceeded the water level WL12 and has reached the water level WL11 corresponding to the first threshold, the main control system CS immediately stops the liquid supply operation of the temperature adjustment device 31. The valves 35 and 35 'are closed to stop the supply of the liquid w, and the substrate stage PST is stopped under the projection optical system PL. Then, the liquid w remaining on the substrate P is transferred to the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ', 36b') via the recovery nozzle 36 (recovery nozzles 36a, 36b, 36a ', 36b'). The liquid is recovered from the recovery tank 61 until it is recovered in the communication recovery tank 61 and the valve 64 is opened and the detection result of the water level sensor becomes the water level WL13. Since the first threshold value is set to a value that can recover more liquid w remaining, the liquid w remaining on the substrate P is all recovered from the time when the supply of the liquid w is stopped. However, the liquid w does not overflow from the recovery tank 61. When the water level of the recovery tank 61 reaches the stop threshold, the valve 45 may be immediately closed and the valve 64 may be opened to start discharging the liquid from the recovery tank 61. Further, when the water level of the recovery tank 61 reaches the stop threshold value, it is considered that the alarm device KD that should be issued when the water level of the recovery tank 61 reaches the alarm threshold value is broken. An alarm device (a warning light, an alarm sound, a display, etc.) different from the above may be provided so as to issue an alarm when the stop threshold of the water level of the recovery tank 61 is reached.

  When the water level of the liquid w stored in the recovery tank 61 during the discharge operation of the recovery tank 61 exceeds the water level WL13 corresponding to the third threshold and reaches the water level WL14 corresponding to the fourth threshold, the main control is performed. The system CS closes the valve 64 provided in the discharge pipe 63 and stops the discharge of the liquid w. In this way, even when the liquid w is being discharged, even if the water level of the liquid w exceeds the water level WL13 corresponding to the third threshold due to malfunction of the water level sensor 62, malfunction due to external noise, or other causes, recovery is performed. When the water level of the liquid w stored in the tank 61 reaches the water level WL14 corresponding to the fourth threshold, the valve 64 is immediately closed to ensure that a certain amount of liquid w is stored in the recovery tank 61. is doing. By performing such control, it is possible to prevent a situation where gas is discharged from the recovery tank 61 together with the liquid w or only the gas is discharged, and the discharge system is not adversely affected.

  As described above, in this embodiment, the liquid discharge operation of the recovery tank 61 is performed during the substrate replacement operation in synchronization with the operation of the exposure apparatus EX. It is possible to prevent a reduction in exposure accuracy due to fluctuations in the liquid recovery force (negative pressure). Further, in the present embodiment, inconveniences such as the liquid w overflowing from the recovery tank 61 or the discharge system of the recovery tank 61 is damaged due to the liquid w in the recovery tank 61 becoming less than a predetermined amount. Therefore, the operation rate of the exposure apparatus EX does not decrease. In the second embodiment described above, four threshold values are set for the water level of the recovery tank 61. However, the recovery tanks 41 and 42 of the first embodiment also have four threshold values as in the second embodiment. A threshold value may be set.

  Further, in the second embodiment described above, the recovery tank 61 is discharged during the substrate replacement operation in synchronization with the operation of the exposure apparatus EX. Not only during the exchange operation, but avoiding the operation requiring high accuracy such as when exposing a shot area on the substrate P or performing mark measurement using an alignment sensor, for example, EGA From the start of calculation until the exposure of the substrate P is started, during the lot processing preparation period, after the completion of exposure of a certain shot area on the substrate P, until the start of exposure of the next shot area, etc. Alternatively, the liquid discharging operation may be performed.

  In the first and second embodiments described above, the discharge from the collection tanks 41, 42, 61 is performed by controlling the valves 49, 50, 64 provided in the discharge pipes 47, 48, 63. However, a gear pump or the like may be used instead of the valve. Furthermore, a check valve may be disposed between the valve (gear pump) and the recovery tank to prevent backflow. In the above-described embodiment, a drain pan (liquid receiving member) for preventing diffusion of the liquid w overflowing from the recovery tanks 41, 42, 61 is disposed below the recovery tanks 41, 42, 61. Anyway. What is necessary is just to determine the magnitude | size (liquid holding | maintenance capability) of a drain pan according to the magnitude | size of each collection tank. Preferably, a drain pan having a recovery capability of about 110 to 120% of the maximum liquid recovery amount of each recovery tank is disposed. Furthermore, a liquid (water) detection sensor may be disposed inside the drain pan to detect that liquid has overflowed from the recovery tanks 41, 42, 61. In this case, it is desirable that the output of the liquid detection sensor disposed inside the drain pan is also supplied to the main control system CS. When the liquid detection sensor arranged inside the drain pan detects the overflow of the liquid, the main control system CS immediately stops the liquid supply operation of the temperature control device 31 and closes the valve 35 to close the liquid w. It is desirable to stop the supply and stop the substrate stage PST under the projection optical system PL. Thereby, it is possible to prevent the liquid w from further overflowing from the drain pan.

  In the first and second embodiments described above, an embodiment has been described in which one ultrapure water production apparatus 30 and one temperature control apparatus 31 are provided for one exposure apparatus EX. When a plurality of exposure apparatuses EX are provided, a temperature adjustment device 31 is provided for each exposure apparatus, and these temperature adjustment devices 31 are connected to, for example, one ultrapure water production apparatus 30 provided in a factory. It is desirable to adopt a configuration to do so.

  In addition, since the exposure apparatus EX of the first and second embodiments described above uses pure water, it is desirable to use a water level sensor that can be used with pure water such as an optical fiber type as the water level sensor. When the purity of the water collected in 41, 42, 61 is lowered, a water level sensor such as a capacitance method or an electric resistance method can be applied. The water level sensor may be one that can continuously monitor the water level in the recovery tank, or may be provided with a water level sensor that detects the water level corresponding to the first to fourth thresholds as described above.

  In the first and second embodiments described above, the water level sensor is applied to the recovery tanks 41, 42, and 61 that store the liquid w recovered by the recovery nozzle 36 on the image plane side of the projection optical system PL. However, the present invention is not limited to this, and can be applied to other recovery tanks such as a liquid trap (liquid recovery tank) provided in the middle of a vacuum system for adsorbing the substrate P to the substrate stage PST. In the first and second embodiments described above, a case is described in which a collection tank that discharges liquid is used when the exposure apparatus EX is not performing an operation that requires high accuracy. The configuration of the water level sensor and the setting of the threshold value in the first and second embodiments, or the operation of the exposure apparatus EX according to the detection result of the water level sensor (for example, the liquid supply stop when the stop threshold value is reached, the exposure operation stop, etc.) Can also be applied to an exposure apparatus having a recovery tank capable of discharging liquid irrespective of the operation of the exposure apparatus EX.

  In the above embodiment, since the illumination optical system IS includes an ArF excimer laser light source, pure water is used as the liquid w. Pure water can be easily obtained in large quantities at a semiconductor manufacturing factory or the like, and has an advantage that it does not adversely affect the photoresist, optical elements (lenses), etc. on the wafer W. In addition, pure water has no adverse effects on the environment, and since the impurity content is extremely low, it can be expected to clean the surface of the wafer W and the surface of the optical element provided on the front end surface of the projection optical system PL. In addition, since the level of pure water in the factory (pure water level) may be low, the exposure apparatus itself may have an ultrapure water purification mechanism.

  The refractive index n of pure water (water) with respect to exposure light having a wavelength of about 193 nm is said to be approximately 1.44. When ArF excimer laser light (wavelength 193 nm) is used as the light source of exposure light, on the wafer W High resolution is obtained by shortening the wavelength to 1 / n, that is, about 134 nm. Further, since the depth of focus is expanded by about n times, that is, about 1.44 times compared with that in the air, the projection optical system PL can be used when it is sufficient to ensure the same depth of focus as that used in the air. The numerical aperture can be further increased, and the resolution is improved in this respect as well.

Note that a KrF excimer laser light source or an F ₂ laser light source can also be used as the light source 1 used for immersion exposure. When the F ₂ laser light source is used, the liquid for immersion exposure may be a fluorine-based liquid such as fluorine-based oil or perfluorinated polyether (PFPE) that can transmit the F ₂ laser light. In addition, it is also possible to use a material (for example, cedar oil) that is transparent to the exposure light, has a refractive index as high as possible, and is stable to the photoresist applied to the projection optical system PL and the surface of the wafer W. Is possible. In this case, a sensor that can detect the amount of liquid in the recovery tank may be one that can detect the liquid.

  As described above, when the immersion method is used, the numerical aperture NA of the projection optical system may be 0.9 to 1.3. When the numerical aperture NA of the projection optical system becomes large in this way, the image formation characteristic may be deteriorated due to the polarization effect with random polarized light conventionally used as exposure light. desirable. In that case, linearly polarized illumination is performed in accordance with the longitudinal direction of the line pattern of the mask line-and-space pattern, and diffraction of the S-polarized component (polarized direction component along the longitudinal direction of the line pattern) is performed from the mask pattern. It is better to emit a lot of light.

  When the space between the projection optical system and the resist coated on the substrate surface is filled with liquid, compared to when the space between the projection optical system and the resist coated on the substrate surface is filled with air (gas) In addition, since the transmittance of the diffracted light of the S-polarized component contributing to the improvement of the contrast on the resist surface is increased, high imaging performance can be obtained even when the numerical aperture NA of the projection optical system exceeds 1.0. Can do. Further, it is more effective to appropriately combine a phase shift mask and an oblique incidence illumination method (particularly a dipole illumination method) or the like according to the longitudinal direction of the line pattern as disclosed in JP-A-6-188169.

In addition to linearly polarized illumination (S-polarized illumination) matched to the longitudinal direction of the mask line pattern, as disclosed in JP-A-6-53120, a tangent (circumference) of a circle centered on the optical axis. A combination of a polarized illumination method that linearly polarizes in the direction) and a grazing incidence illumination method is also effective.
In particular, when a mask pattern includes not only a line pattern extending in a predetermined direction but also a plurality of line patterns extending in different directions, as disclosed in JP-A-6-53120, By using both the polarization illumination method that linearly polarizes in the tangential direction of the circle centered on the axis and the annular illumination method, high imaging performance can be obtained even when the numerical aperture NA of the projection optical system is large.

  In the above-described embodiment, an immersion exposure apparatus that locally fills the space between the projection optical system PL and the wafer W with a liquid is employed. However, as disclosed in JP-A-6-124873. An immersion exposure apparatus for moving a stage holding a substrate to be exposed in the liquid tank, and a liquid tank having a predetermined depth on the stage as disclosed in JP-A-10-303114, The present invention can also be applied to an immersion exposure apparatus that holds a substrate therein.

Further, the present invention separately mounts a substrate to be processed such as a wafer as disclosed in JP-A-10-163099, JP-A-10-214783, JP-T 2000-505958, and the like. The present invention can also be applied to a twin stage type exposure apparatus having two stages that can move independently in the XY directions.
Note that the present invention can also be applied to an exposure apparatus that includes a measurement stage mounted with a measurement member or sensor and moved on the image plane side of the projection optical system separately from the stage holding the substrate P. An exposure apparatus equipped with a measurement stage is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-164504 (corresponding US Application No. 09 / 593,800), which is designated in the international application (or selected selected country). To the extent permitted by national laws and regulations), the disclosures in the above publications and corresponding US applications are incorporated herein by reference.

Furthermore, in the above-described embodiment, the ArF excimer laser light source is described as an example of the light source. However, as the light source other than this, for example, an ultra-light emitting g-line (wavelength 436 nm) or i-line (wavelength 365 nm) is emitted. A high-pressure mercury lamp, a KrF excimer laser (wavelength 248 nm), an F ₂ laser (wavelength 157 nm), a Kr ₂ laser (wavelength 146 nm), a YAG laser high-frequency generator, or a semiconductor laser high-frequency generator can be used.

  Further, a single wavelength laser beam in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser as a light source is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and yttrium), and nonlinear optics You may use the harmonic which wavelength-converted into the ultraviolet light using the crystal | crystallization. For example, if the oscillation wavelength of a single wavelength laser is in the range of 1.51 to 1.59 μm, the generated wavelength is in the range of 189 to 199 nm, the eighth harmonic, or the generated wavelength is in the range of 151 to 159 nm. A 10th harmonic is output.

Further, if the oscillation wavelength is in the range of 1.03 to 1.12 μm, the seventh harmonic whose output wavelength is in the range of 147 to 160 nm is output, and in particular, the oscillation wavelength is in the range of 1.099 to 1.106 μm. If it is inside, the 7th harmonic in the range of 157 to 158 μm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained. In this case, for example, an yttrium-doped fiber laser can be used as the single wavelength oscillation laser.

Further, the glass material of the optical element provided in the illumination optical system IS, as the glass material of refractive members constituting the projection optical system PL in accordance with the wavelength of the exposure light, fluorite (calcium fluoride: CaF ₂₎ or magnesium fluoride It is selected from optical materials that transmit vacuum ultraviolet light such as fluoride crystals such as (MgF ₂ ) or mixed crystals thereof, or quartz glass doped with a substance such as fluorine or hydrogen. In addition, since quartz glass doped with a predetermined substance has a reduced transmittance when the wavelength of exposure light is shorter than about 150 nm, when using vacuum ultraviolet light having a wavelength of about 150 nm or less as exposure light, As an optical material, fluoride crystals such as fluorite (calcium fluoride) and magnesium fluoride or mixed crystals thereof are used.

In the above embodiment, the step-and-scan type exposure apparatus has been described as an example. However, the present invention can also be applied to a step-and-repeat type exposure apparatus. Further, the present invention is not limited to an exposure apparatus used for manufacturing a semiconductor element, but also used for manufacturing a display including a liquid crystal display element (LCD) and the like, and an exposure apparatus for transferring a device pattern onto a glass plate, and a thin film magnetic head. The present invention can also be applied to an exposure apparatus that is used for manufacturing and transfers a device pattern onto a ceramic wafer, and an exposure apparatus that is used to manufacture an image sensor such as a CCD.
Further, the exposure apparatus to which the above-described liquid immersion method is applied is configured to expose the substrate P by filling the optical path space on the light emission side of the optical element 1 at the tip of the projection optical system PL with liquid (pure water). However, as disclosed in International Publication No. 2004/019128, the optical path space on the incident side of the optical element 1 of the projection optical system PL may be filled with liquid (pure water).
It is also possible to use a type of exposure apparatus that does not have a projection optical system, such as a proximity type exposure apparatus or a two-beam interference type exposure apparatus that exposes a wafer by forming interference fringes on the wafer.

  Next, an embodiment of a method of manufacturing a micro device using the exposure apparatus according to the embodiment of the present invention in a lithography process will be described. FIG. 6 is a flowchart showing an example of a manufacturing process of a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 6, first, in step S10 (design step), a function / performance design (for example, circuit design of a semiconductor device) of a micro device is performed, and a pattern design for realizing the function is performed. Subsequently, in step S11 (mask manufacturing step), a mask (reticle) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S12 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

  Next, in step S13 (wafer processing step), as will be described later, an actual circuit or the like is formed on the wafer using lithography and the like using the mask and wafer prepared in steps S10 to S12. Next, in step S14 (device assembly step), device assembly is performed using the wafer processed in step S13. This step S14 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary. Finally, in step S15 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice manufactured in step S14 are performed. After these steps, the microdevice is completed and shipped.

  FIG. 7 is a diagram showing an example of a detailed flow of step S13 in FIG. 6 in the case of a semiconductor device. In FIG. 7, in step S21 (oxidation step), the surface of the wafer is oxidized. In step S22 (CVD step), an insulating film is formed on the wafer surface. In step S23 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step S24 (ion implantation step), ions are implanted into the wafer. Each of the above steps S21 to S24 constitutes a pretreatment process at each stage of the wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above-described pre-processing step is completed, the post-processing step is executed as follows. In this post-processing step, first, in step S25 (resist formation step), a photosensitive agent is applied to the wafer. In step S26 (exposure step), the circuit pattern of the mask is transferred to the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, in step S27 (development step), the exposed wafer is developed, and in step S28 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step S29 (resist removal step), the resist that has become unnecessary after the etching is removed. By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the wafer.

Claims (24)

In an exposure apparatus that exposes a substrate through a projection optical system and a liquid,
A liquid recovery device that recovers the liquid supplied to the image plane side of the projection optical system in a recovery unit via a recovery port;
An exposure apparatus comprising: a control device that controls an operation of discharging the liquid collected by the collection unit from the collection unit in synchronization with the operation of the exposure apparatus.   The exposure apparatus according to claim 1, wherein the controller performs control to discharge the liquid from the recovery unit when the substrate is not exposed. Comprising a measuring device for measuring position information of a mark formed on the substrate;
3. The exposure apparatus according to claim 1, wherein the control device performs control to discharge the liquid from the recovery unit when the measurement of the mark by the measurement device is not performed.   The exposure apparatus according to claim 1, wherein the control device performs control to discharge the liquid from the recovery unit while the substrate is being replaced. A plurality of the recovery units are provided,
2. The exposure apparatus according to claim 1, wherein the control device performs control to switch the collection unit connected to the collection port in synchronization with an operation of the exposure apparatus.   6. The exposure apparatus according to claim 5, wherein the control device performs control to discharge the collected liquid to a collection unit that is not connected to the collection port. The control device, when the exposure processing of the substrate is completed, whenever the exposure processing of the substrate in units of a plurality of sheets is completed, or when the exposure processing of a plurality of partition areas set on the substrate is completed, 6. The exposure apparatus according to claim 5, wherein control is performed to switch the collection unit connected to the collection port. In an exposure apparatus that exposes a substrate through a projection optical system and a liquid,
A liquid recovery device that recovers the liquid supplied to the image plane side of the projection optical system in a recovery unit via a recovery port;
A control device for controlling the operation of the liquid recovery device,
The liquid recovery apparatus has a plurality of recovery units,
The exposure apparatus is characterized in that the control device controls switching of a collection unit connected to the collection port.   9. The exposure apparatus according to claim 8, wherein the controller discharges the liquid recovered from a recovery unit that is not connected to the recovery port. In an exposure apparatus that exposes a substrate through a projection optical system and a liquid,
A liquid supply device for supplying a liquid to the image plane side of the projection optical system;
A liquid recovery apparatus that recovers the liquid supplied to the image plane side of the projection optical system in a recovery unit;
A liquid level detection system for detecting the surface position of the liquid recovered in the recovery unit;
An exposure apparatus comprising: a control device that controls liquid supply from the liquid supply device based on a detection result of the liquid level detection system.   The exposure apparatus according to claim 10, wherein the control device stops the liquid supply from the liquid supply device when the surface position of the liquid recovered by the recovery unit reaches a first position.   The first position is set so that the liquid supplied to the image plane side of the projection optical system can be recovered by the recovery unit after the liquid supply is stopped. 11. The exposure apparatus according to 11.   12. The exposure apparatus according to claim 11, wherein the control device issues a warning when the surface position of the liquid recovered by the recovery unit reaches a second position lower than the first position.   The control device is configured so that the surface position of the liquid recovered by the recovery unit is maintained between a second position lower than the first position and a third position lower than the second position. The exposure apparatus according to claim 11, wherein the liquid collected in the part is discharged. The said control apparatus stops discharge | emission of the liquid from the said collection | recovery part, when the surface position of the liquid collect | recovered by the said collection | recovery part reaches the 4th position lower than the said 3rd position. Item 15. The exposure apparatus according to Item 14.   The apparatus further includes a substrate stage that holds the substrate and is movable on the image plane side of the projection optical system, and the control device is configured such that the surface position of the liquid recovered by the recovery unit reaches the first position. The exposure apparatus according to claim 10, wherein the substrate stage is stopped.   A device manufacturing method using the exposure apparatus according to any one of claims 1, 8, and 10. A liquid processing method in an exposure apparatus that exposes a substrate through a liquid,
A recovery step of recovering the supplied liquid to the recovery unit;
And a discharging step of discharging the liquid recovered by the recovery unit from the recovery unit in synchronization with the operation of the exposure apparatus.   The liquid processing method according to claim 18, wherein the substrate is exposed through a liquid supplied to an image plane side of the projection optical system. A liquid processing method in an exposure apparatus that exposes a substrate through a liquid,
A first recovery step of connecting the recovery port for recovering the supplied liquid and the first recovery unit, and recovering the supplied liquid to the first recovery unit;
A second recovery step of connecting the recovery port and a second recovery unit different from the first recovery unit, and recovering the supplied liquid to the second recovery unit;
And a discharging step of discharging the liquid recovered by the first recovery unit not connected to the recovery port from the first recovery unit. 21. The liquid processing method according to claim 20, wherein the substrate is exposed through a liquid supplied to an image plane side of the projection optical system. A liquid processing method in an exposure apparatus that exposes a substrate through a liquid, comprising: supplying a liquid onto the substrate;
A recovery step of recovering the liquid supplied on the substrate in a recovery unit;
And a stopping step of stopping the supply of the liquid when the surface of the liquid recovered by the recovery unit reaches a predetermined position. The liquid processing method according to claim 22, wherein the substrate is exposed through a liquid supplied to an image plane side of the projection optical system.   An exposure method for exposing a substrate using the liquid processing method according to any one of claims 18, 20, and 22.

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