JP2005175176A - Exposure method and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an immersion exposure method having a highly precise wafer Z position measuring method and a Z position control method, and to provide a device manufacturing technology to manufacture a high performance device by using the exposure technology. <P>SOLUTION: The measuring electrode of an electric capacity type position detecting device is arranged in a projection optical system or its neighborhood, the electric capacity of the capacity formed between the measuring electrode and the wafer is measured, and the focus control of a substrate to be exposed is executed based on this. A conductive thin film is formed on the surface of the substrate to be exposed so that the electric capacity can be limited to the electric capacity of the capacity formed between the measuring electrode and the conductive thin film, and that the fluctuation of the electric capacity accompanied with the structure of the substrate to be exposed can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection exposure technique used in a lithography process for manufacturing various devices such as a semiconductor integrated circuit (LSI or the like), an image sensor, or a liquid crystal display, and more specifically, in the exposure, the exposure is performed. The present invention relates to a so-called immersion projection exposure technique in which a liquid is filled between a projection optical system to be used and a substrate for forming the various devices. The present invention also relates to a device manufacturing technique using the exposure technique.

  When forming a fine pattern of an electronic device such as a semiconductor integrated circuit or a liquid crystal display, a pattern of a reticle (or a photomask, etc.) as a mask drawn by enlarging the pattern to be formed approximately 4 to 5 times is projected. A method of reducing and exposing to a photosensitive film (photoresist) on a wafer (or glass plate or the like) as an exposed substrate through an optical system is used. For the exposure transfer, a stationary exposure type projection exposure apparatus such as a stepper and a scanning exposure type projection exposure apparatus such as a scanning stepper are used. The resolution of the projection optical system is proportional to the value obtained by dividing the exposure wavelength by the numerical aperture (NA) of the projection optical system. The numerical aperture (NA) of the projection optical system is obtained by multiplying the sine of the maximum incident angle of the illumination light for exposure to the wafer by the refractive index of the medium through which the light beam passes.

  Therefore, in order to cope with miniaturization of semiconductor integrated circuits and the like, the exposure wavelength of the projection exposure apparatus has been made shorter. At present, the main exposure wavelength is 248 nm of the KrF excimer laser, but the 193 nm of the shorter wavelength ArF excimer laser is also entering the practical stage. Further, there has been proposed a projection exposure apparatus using a so-called vacuum ultraviolet light source such as an F2 laser having a shorter wavelength of 157 nm and an Ar2 laser having a wavelength of 126 nm.

  However, in order to shorten the exposure wavelength, it is necessary to develop a lens material that transmits the exposure wavelength satisfactorily and a photoresist that exhibits good performance at the exposure wavelength. As a result, shortening the exposure wavelength requires a long development period.

  In addition to shortening the wavelength, it is possible to increase the resolution by increasing the numerical aperture (increasing NA) of the projection optical system. Therefore, development has been made to further increase the NA of the projection optical system. The NA of the current state-of-the-art projection optical system is about 0.8. However, as long as the optical path of the exposure light between the projection optical system and the wafer is filled with a gas having a refractive index of approximately 1, the theoretical upper limit is 1, and the current NA is close to the theoretical upper limit.

Therefore, an immersion exposure method has been proposed in which exposure is performed by filling a liquid having a predetermined refractive index in the optical path space between the projection optical system and the wafer (see, for example, Patent Document 1 and Non-Patent Document 1). As described above, the NA of the projection optical system is obtained by multiplying the sine of the maximum incident angle on the wafer by the refractive index of the medium through which the light beam passes, so that the immersion exposure method is performed between the projection optical system and the wafer. By filling the optical path space with a liquid having a predetermined refractive index, the NA of the projection optical system is increased by the refractive index multiple, thereby improving the resolution.
International Publication No. WO99 / 49504 BJ Lin: "Semiconductor Foundry Lithography, and Partners", SPIE (USA) Vol.4688, PP 11-24 (2002)

  In these exposure methods, the depth of focus at which a good projection image of the pattern on the reticle can be obtained is extremely narrow, for example, about 0.5 μm or less, so that the wafer accurately matches the focal position of the projection optical system during exposure. Focus control is necessary to make it happen. Conventionally, this focus control is performed based on a measurement value of a wafer surface position (more precisely, a position of a photoresist surface formed on the wafer) using an oblique incidence optical position sensor.

  This is because the position detection light is irradiated at an oblique incidence onto the wafer surface via the optical path space between the projection optical system and the wafer, and the return light is detected via the optical path space between the projection optical system and the wafer. Then, the position of the wafer surface or the like in the optical axis direction of the projection optical system (hereinafter referred to as “Z position”) is detected.

In order to construct the oblique incidence optical position sensor as described above, it is necessary that the distance between the projection optical system and the wafer be relatively long in order to secure the optical path of the irradiation light and the return light. .
However, in the above immersion exposure method, it is difficult to increase the distance between the projection optical system and the wafer.

  For example, even for exposure light with a wavelength of 193 nm emitted from an ArF laser, there is no liquid that does not absorb this, and fluctuations in temperature or density that occur in the liquid that fills the optical path of the exposure light are caused by the exposure light flux. This is because the optical path length of the exposure light in the liquid is desirably as short as possible because wavefront aberration is given.

  As a result, in the immersion exposure method, it is difficult to construct a conventional oblique incidence optical position sensor, and an alternative method for measuring the Z position of the wafer is required.

  The present invention has been made in view of such problems, and a first object thereof is to provide an immersion exposure method having a highly accurate wafer Z position measurement method and Z position control method.

  Another object of the present invention is to provide a device manufacturing technique capable of manufacturing a high-performance device using the above exposure technique.

  The first exposure method of the present invention is an exposure method for exposing the pattern on the first object (R) to the photosensitive film (53) on the second object (W) via the projection optical system (7). And forming at least one thin film including the photosensitive film on the second object, and an optical path space (31) between the thin film on the second object and the projection optical system with a liquid. Electricity formed between the filling step, the measurement electrode (30a, 30b) attached to or near the projection optical system, and the second object on which at least one thin film is formed A step of measuring a capacitance (capacitance) in a state where the liquid is filled, and a focus relationship between the first object and the second object via the projection optical system based on the measured value of the electric capacity A focus control step to control the second object In a state where the liquid is filled between the film and the projection optical system, the first object is irradiated with exposure light, and the pattern on the first object is exposed to the photosensitive film on the second object. And at least one of the at least one thin film including the photosensitive film is a conductive thin film (53, 54, 55).

  In the present invention, the capacitance formed by the measurement electrode and the second object on which the at least one thin film is formed changes depending on the distance between the two, and the capacitance is obtained. And controlling the Z position of the second object with respect to the projection optical system, or controlling the Z position of the first object with respect to the projection optical system, so that the projected image of the pattern on the first object is It is possible to project onto the photosensitive film formed on the second object at or near the focal position.

  Furthermore, in the present invention, since at least one of the at least one thin film including the photosensitive film formed on the second object is a conductive thin film, the measured electric capacitance In accordance with the distance between the conductive thin film on the second object and the measurement electrode. That is, it can be made independent of the structure of the second object or the like below the conductive thin film. As a result, the Z position measurement accuracy and the Z position measurement accuracy of the second object can be increased.

In this case, the conductive thin film can be a film made of an organic material.
Further, as an example, the conductive thin film can be a lower layer thin film formed in a lower layer (side closer to the second object) than the photosensitive film. In this case, the lower layer thin film may be an antireflection film that prevents reflection of exposure light used for the exposure.

  Alternatively, as an example, the conductive thin film may be an upper thin film formed in an upper layer than the photosensitive film. In this case, the upper layer thin film may be an antireflection film that prevents reflection of the exposure light.

These antireflection films can further improve the resolution and depth of focus of the exposure method of the present invention.
As an example, the measurement of the capacitance can be performed in a state where a conductive member that is electrically connected to at least a part of the exposure apparatus is in contact with the conductive thin film on the second object.

  Further, the focus control step can be performed based on the correction value determined from the configuration of the thin film in addition to the measured value of the capacitance. Therefore, as described above, when the conductive thin film is different from the photosensitive film, the correction value obtained from the distance between the conductive thin film and the photosensitive film and the dielectric constant of each material is taken into consideration. Thus, the focus control can be performed.

Thereby, focus control (Z position control) with higher accuracy can be performed.
As an example, the distance between the measurement electrode and the second object is preferably 3 mm or less. Thereby, the measurement accuracy of the electric capacity can be improved.

  As an example, the measurement electrode may be one provided on a part of a transmissive optical member that constitutes the projection optical system. Further, the measurement electrode is a thin film formed on the surface of the transmissive optical member that is disposed closest to the second object among the transmissive optical members constituting the projection optical system, on the second object side surface. Electrodes can also be used.

  Moreover, what is transparent with respect to the exposure light can also be used for the thin film electrode provided in the transparent optical member. In that case, as an example, the exposure light is ultraviolet light having a wavelength of 193 nm, and the thin film electrode can be a thin film mainly composed of magnesium oxide or aluminum oxide.

The liquid can also be water.
The focus control step can include a step of adjusting the position and angle of the second object with respect to the projection optical system.

Further, the exposure step can include an exposure step by scanning exposure performed while relatively scanning the first object and the second object with respect to the projection optical system.
Next, the device manufacturing method of the present invention is a device manufacturing method including a lithography process, and the pattern image on the mask as the first object is the second object by using the exposure method of the present invention. Based on an exposure process for exposing the photosensitive film on the substrate to be processed, a developing process for developing the photosensitive film after the exposure process, and a pattern comprising the photosensitive film formed through the exposure process and the developing process. A device manufacturing method including a processing step of forming a pattern corresponding to the image of the pattern on the mask on the substrate to be processed.

  As a result, it is possible to achieve good focus controllability even with the immersion exposure method, and it is possible to manufacture finer and higher performance devices without impairing the high resolution of the immersion exposure method. Become.

  Moreover, the process of removing the electroconductive thin film can be included in the image development process or the processing process as needed. Thereby, unnecessary electrical conductivity in the manufactured device can be removed, and a highly reliable device can be manufactured.

  According to the present invention, in the immersion exposure method, the Z positional relationship between the projection optical system and a second object (wafer) formed with a predetermined photosensitive film is attached to the projection optical system, or Since the calculation is based on the measured value of the capacitance formed between the measurement electrode provided in the vicinity and the conductive thin film provided on the second object, the wafer Z position can be measured with high accuracy.

  Therefore, highly accurate focus controllability can be realized even in the immersion exposure method in which the configuration of the conventional oblique incidence optical position sensor is difficult. As a result, it is possible to provide a high-resolution exposure method that can fully exhibit the high resolution of the immersion exposure method.

  In addition, by using the exposure method of the present invention in the lithography process, a device manufacturing method capable of manufacturing a high-performance device having a finer pattern can be provided.

  Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings. In this example, as disclosed in Patent Document 1, a liquid is locally supplied to an optical path space between a projection optical system and a second object, such as a wafer, to realize an immersion exposure method. The present invention is applied to the case where immersion exposure is performed by a local immersion type immersion exposure apparatus. Further, the exposure apparatus used in this example is a scanning exposure type projection exposure apparatus (scanning stepper) having a step-and-scan method.

FIG. 1 is a partially cutaway view showing a schematic configuration of an exposure apparatus suitable for use in the exposure method of this example. The projection exposure apparatus includes a light source 1, an illumination optical system 2, a projection optical system 7, and the like. It has.
The illumination optical system 2 shapes the illumination light (exposure light) from the light source 1 and equalizes the illuminance, and irradiates the reticle R (also referred to as a photomask or simply a mask). Here, a pattern to be exposed and transferred is formed on the lower surface of the reticle R in the drawing.

  The projection optical system 7 reduces an image obtained by reducing the pattern in the illumination field of the reticle R illuminated with the exposure light with a projection magnification M (M is a reduction magnification such as 1/4, 1/5, etc.) Projection is performed on an exposure region on one shot region on a photosensitive thin film (not shown) formed on a workpiece substrate (wafer) W such as a glass plate. Reticle R and wafer W can also be regarded as a first object and a second object, respectively.

  The projection exposure apparatus of this example is a local immersion type immersion exposure apparatus, and the optical path space between the projection optical system 7 and the wafer W is covered with a local immersion mechanism 8, and the interior is filled with a predetermined liquid. It is. For example, the liquid supplied from the utility supply facility of the semiconductor factory to the exposure apparatus is adjusted to a predetermined temperature by the liquid supply mechanism 9 and supplied to the local liquid immersion mechanism 8 through the supply pipe 10. Further, the liquid used for filling the exposure optical path space in the local liquid immersion mechanism 8 is recovered by the recovery mechanism 12 via the recovery tube 11 and discarded outside the exposure apparatus.

  The reticle R is held by the reticle stage 3 by means such as suction. Since the projection exposure apparatus of this example is a scanning stepper, the reticle stage 3 can be scanned in the Y direction on the reticle base 5 and can also be moved by a minute distance in the X direction. Accordingly, the reticle R can also be scanned in the Y direction, and can also be moved by a minute distance in the X direction.

  On the other hand, the wafer W is held on the wafer stage 14 by means such as suction. The wafer stage 14 can also be scanned in the Y direction on the wafer base 17 and can also be moved in the X direction (stepping operation). Therefore, the wafer W can also be scanned in the Y direction and in the X direction. Is also movable. The wafer stage 14 also has a Z fine movement mechanism that can move the wafer W in a small amount in the Z direction, and a tilt mechanism that can finely adjust the angle (tilt angle) formed by the surface of the wafer W with respect to the XY plane. Have. Details thereof will be described later.

  The exposure of the photosensitive thin film on the wafer W is performed by scanning the reticle R and the wafer W in the Y direction with the reticle stage 3 and the wafer stage 14 via the projection optical system 7 while maintaining the imaging relationship. 1 and the illumination optical system 2 irradiate the reticle R with illumination light.

  At this time, the image formation relationship between the reticle R and the wafer W via the projection optical system 7 is maintained by the main control system 19, a reticle stage drive mechanism and reticle stage control system 20 (not shown), and a wafer stage (not shown). This is performed by the drive mechanism and the wafer stage control system 21.

  Among these, the positional relationship in the X direction and the Y direction is controlled by the reticle laser interferometer 6, the position information of the reticle stage 3 and the reticle R held by the reticle stage 3, and the wafer laser interferometer. 16 is performed based on the wafer stage 14 measured via the wafer fixing mirror 15 and the positional information of the wafer W held by the wafer stage 14.

  That is, the measurement value of the reticle laser interferometer 6 is transmitted to the reticle stage control system 20, and the difference from the specified value sent from the main control system 19 is compared and examined, so that the reticle stage 3 is brought closer to the specified value. A command is transmitted to the drive mechanism. On the other hand, the measurement value of the wafer laser interferometer 16 is transmitted to the wafer stage control system 21 and the difference from the specified value sent from the main control system 19 is compared and examined, and the wafer stage is driven so that the wafer stage 14 is closer to the specified value. A command is transmitted to the mechanism.

  After the exposure to one shot area on the wafer W is completed by the above scanning exposure, the wafer stage is moved by a predetermined amount in the X direction or the Y direction to perform exposure to each shot area on the wafer W. The operation is repeated to complete exposure to all shot areas on the wafer W.

  Since FIG. 1 is a cross-sectional view, both the reticle interferometer 6 and the wafer interferometer 16 display only an interferometer that performs position measurement in the Y direction, and no interferometer that performs position measurement in the X direction is displayed. It goes without saying that both the reticle interferometer 6 and the wafer interferometer 16 also include an interferometer that measures the position in the X direction.

  By the way, when an existing pattern exists on the wafer W, it is necessary to expose the pattern to be exposed and transferred in the main exposure step while maintaining a predetermined positional relationship with the existing pattern. Therefore, prior to exposure, the position of an existing pattern on the wafer W is detected by a position sensor 13 provided in the vicinity of the projection optical system 7, while a position sensor (not shown) is also used for the position of the pattern on the reticle R. It is preferable to perform exposure by aligning the projected image of the pattern on the reticle R at a position having a predetermined relationship with respect to the existing pattern existing on the wafer W based on the positional information. .

  Further, with respect to the positional relationship (focus relationship) in the Z direction, this control (focus control) is performed based on the information regarding the Z direction position of the wafer W output from the capacitance type position measurement mechanism control unit 18. That is, the main control system calculates the correction amount of the position of the wafer W in the Z direction and the correction amount of the tilt angle necessary for maintaining the imaging relationship based on the output signal from the capacitive position measurement mechanism control unit 18. This is transmitted to the wafer stage control system 21. Then, the wafer stage control system 21 drives the Z fine movement mechanism and the tilt mechanism in the wafer stage 14 based on the transmitted correction amount to set the surface of the wafer W at a predetermined Z position and a predetermined inclination angle. To do. Thereby, a predetermined focus relationship between the reticle R and the wafer W is maintained.

  Hereinafter, a first embodiment of the local liquid immersion mechanism 8 used in the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a first embodiment of the local liquid immersion mechanism. The local liquid immersion mechanism of this example includes inner walls 24a and 24b arranged so as to surround the exposure optical path space 31, a lower end surface 29a, 29b is a main component.

  Since FIG. 2 is a sectional view, the inner walls 24a and 24b and the lower end surfaces 29a and 29b are divided and displayed. However, the actual shape is an exposure optical path space such as a cylindrical shape or an annular shape. It has an integral shape surrounding 31. Openings AP are provided in the lower end surfaces 29a and 29b to transmit exposure light.

  The supply pipe 10 is connected to one of the inner walls 24a and 24b, and the temperature-adjusted liquid is supplied from the liquid supply mechanism 9 into the upstream spare chamber 25. Then, the exposure optical path space 31 between the transparent optical member 40 and the wafer W disposed closest to the wafer W among the transparent optical members such as lenses constituting the projection optical system 7 passes through the upstream rectifying member 22. Filled.

  If the exposure light is a light beam having a wavelength of 193 nm emitted from an ArF laser, it is desirable to use water that is relatively transparent and inexpensive for this wavelength. It is also desirable to use water when the exposure light has a longer wavelength. On the other hand, when the exposure light has a shorter wavelength than this, since the absorbability for the exposure light is increased, it is desirable to use another liquid such as a fluorinated oil.

On the other hand, the recovery pipe 11 is connected to the other inner wall 24 b and connected to the recovery mechanism 12.
Then, the liquid in the exposure optical path space 31 is sucked into the downstream preliminary chamber 26 via the downstream rectifying member 23 and sucked into the recovery mechanism 12 via the recovery pipe 11 by the vacuum suction by the recovery mechanism 12.

Here, the upstream rectifying member 22 and the downstream rectifying member 23 are porous objects made of, for example, ceramic or metal, and are used to allow liquid to pass through each porous hole.
Or what consists of meshes, such as a metal, can also be used as the upstream rectification member 22 and the downstream rectification member 23. FIG.

  Part of the liquid that has reached the wafer W through the openings AP of the lower end surfaces 29a and 29b leaks to the surroundings through the gaps 32a and 32b formed between the lower end surfaces 29a and 29b and the wafer W. There is a possibility to put out. Therefore, for example, cylindrical outer walls 27a and 27b are provided outside the inner walls 24a and b having a cylindrical shape to form exhaust spaces 33a and 33b, and suction pipes 28a and 28b are provided in a part of the gaps 32a and 27b. The liquid that leaks out to the surroundings through 32b may be sucked and discarded by the suction action of the suction pipes 28a and 28b.

  In order to completely prevent the liquid from leaking out, the flange members 34a and 34b may be provided on the outer side (the side farther from the optical path space 31) than the outer walls 27a and 27b. Further, the suction pipes 28a and 28b can be connected to the recovery mechanism 12 in FIG. 1, and the vacuum exhaust equipment of a semiconductor factory where the exposure apparatus is installed without using the mechanism provided in the exposure apparatus. You can also connect directly.

Further, the transparent optical member 40 is held by the airtight holding mechanisms 41a and 41b, whereby the liquid can be prevented from flowing into the projection optical system 7.
In the first embodiment, the measurement electrodes 30a and 30b, which are features of the present invention, are installed on the lower end surfaces 29a and 29b of the local liquid immersion mechanism. The measurement electrodes 30a and 30b form a capacitor between the measurement electrode 30a and the wafer W disposed opposite to the measurement electrode 30a and b, thereby forming an electric capacitance (capacitance). The electric capacity of the capacitor formed by each of the measurement electrodes 30a and 30b is proportional to the area of the measurement electrodes 30a and 30b and the dielectric constant of the liquid filling the gaps 32a and 32b between the measurement electrodes 30a and 30b and the wafer W. It is inversely proportional to the distance between the measurement electrodes 30a, 30b and the wafer W.

  Here, since the area of the measurement electrodes 30a and 30b and the dielectric constant of the liquid are constant, the distance between the measurement electrodes 30a and 30b and the wafer W is measured by measuring the capacitance of the capacitor formed by the measurement electrodes 30a and 30b. Can be measured.

The measurement electrodes 30a and 30b are connected to the capacitance type position measurement mechanism control unit 18 in FIG.
The capacitance type position measurement mechanism control unit 18 measures a resonance frequency of, for example, an LC circuit including the capacitor (an electric circuit having a predetermined inductance and including the capacitor) for measuring the capacitance of the capacitor. Or an electric circuit that inputs an electric signal having a predetermined frequency and phase to the capacitor and detects a difference in phase relationship between a voltage and a current constituting the signal.

  Note that the electric circuit included in the capacitance type position measurement mechanism control unit 18 is not limited to this, and may be of any other type. The information output from the capacitance type position measurement mechanism control unit 18 to the main control system 19 may also be information on the distance (length) between the wafer W and the measurement electrode, which is simply the capacitance or resonance frequency. Alternatively, it may be phase difference information between a voltage signal and a current signal. If the output is other than the interval information, the main control system 19 may convert the information into interval information.

  As described above, the main control system 19 drives the Z fine movement mechanism and the tilt mechanism in the wafer stage 14 on the basis of the information from the capacitance type position measurement mechanism control unit 18, thereby moving the surface of the wafer W to a predetermined Z. Set the position and the predetermined tilt angle. As a result, a predetermined focus relationship between the reticle R and the wafer W is maintained.

  In the first embodiment, the measurement electrodes 30a and 30b are not disposed on the projection optical system 7 itself, but on the lower end surfaces 29a and 29b of the local liquid immersion mechanism in the vicinity of the projection optical system 7. The distance measured by the measurement electrodes 30a and 30b does not necessarily represent the distance between the projection optical system 7 and the wafer W.

  However, for example, by fixing the local liquid immersion mechanism 8 including the lower end surfaces 29a and 29b firmly to the projection optical system 7, by eliminating the relative position fluctuation between the projection optical system 7 and the measurement electrodes 30a and 30b, Although having a fixed offset value, the distance between the projection optical system 7 and the wafer W can be substantially measured.

  In addition, the measurement electrodes 30a and 30b are not limited to the lower end surfaces 29a and 29b of the above-described local liquid immersion mechanism, as long as the relationship with the projection optical system 7 is fixed in this way. Needless to say, it can also be set. Therefore, for example, when the projection optical system 7 is covered with a constant temperature mechanism (not shown) for adjusting the temperature, the positional relationship between the constant temperature mechanism and the projection optical system 7 is at least within a predetermined time. If it is fixed, the measuring electrodes 30a and 30b can be provided in the thermostatic mechanism or the like.

Here, the predetermined time is, for example, the time required for exposure of one lot (processing unit) of the wafer W.
The measurement electrodes 30a and 30b used in this example can be flat plates made of metal or the like. Since the measurement electrodes 30a and 30b are exposed to a liquid that fills the exposure optical path space 31, it is desirable to use a substance that is not corroded by the liquid. Specifically, for example, platinum or gold is preferably used.

  Next, a second embodiment of the local liquid immersion mechanism 8 used in the present invention will be described with reference to FIG. Since many members constituting the second embodiment are common to the members constituting the first embodiment, the same reference numerals are assigned to the same members, and descriptions thereof are omitted.

  In the second embodiment, the transparent optical member 40 disposed closest to the wafer W among the transparent optical members such as lenses constituting the projection optical system 7 is disposed close to the wafer W. . As a result, there is no room for the upstream rectifying member 22 to be disposed in the same manner as in the first embodiment. Therefore, in this example, the upstream rectifying member 22 and the downstream rectifying member 23 are arranged on the wafer W as shown in FIG. They are arranged in parallel orientation.

  Accordingly, the liquid filling the exposure optical path space 31 passes downward from the upstream preliminary chamber 25 through the upstream rectifying member 22 to the upstream gap 32a, and flows from there to the right in the figure to fill the exposure optical path space 31. Further, it flows in the right direction in the figure, passes through the downstream gap 32 b, is sucked upward by the downstream rectifying member 23, and reaches the downstream preliminary chamber 26.

  In the second embodiment, the measurement electrodes 30 a and 30 b are formed on the wafer-side surface 40 a of the transparent optical member 40. An example of the measurement electrodes 30a and 30b arranged on the surface 40a will be described with reference to FIG. FIG. 4 is a view of the transparent optical member 40 as viewed from below in FIG. 3, and 5 along the X direction at a position a predetermined distance in the + Y direction from the optical axis AX of the projection optical system 7 that is the center. The measurement electrodes 30g, 30i, 30a, 30c, and 30e are arranged side by side, and the five measurement electrodes 30h, 30j, 30b, and the like along the X direction are positioned at a predetermined distance from the optical axis AX in the -Y direction. This represents a state in which 30d and 30f are arranged side by side.

  Further, the measurement electrodes 30a to 30j are formed with conductive wires 35g, 35i, 35a, 35c, 35e and 35h, 35j, 35b, 35d, 35f that transmit electric signals to the electrodes. The conducting wires 35a to 35j are connected to the capacitance type position measurement mechanism control unit 18 by wiring members (not shown).

  Here, a portion indicated by a broken line is the exposure field 43 of the projection optical system 7 on the wafer W, and a hatched portion within a predetermined distance from the exposure optical field 43 is exposed to the exposure field 43 on the surface 40a. The exposure light transmission region 42 is transmitted.

  In this example, all of the measurement electrodes 30a to 30j are arranged other than the exposure light transmission region 42 on the surface 40a. Therefore, there is an advantage that as the measurement electrodes 30a to 30j, electrodes that are opaque to exposure light and have strong corrosion resistance against liquids such as platinum and gold can be used.

  On the other hand, since the measurement electrode that is opaque to the exposure light cannot be disposed at a position immediately above the exposure field 43 on the wafer W, the distance between the wafer W and the projection optical system 7 in the exposure field 43 (Z position). ) Cannot be measured.

  However, since the exposure apparatus of the present embodiment is a scanning exposure type projection exposure apparatus, the exposure field is aligned along the scanning direction (Y direction) of the wafer stage 14 before the wafer W is placed in the exposure field 43. It is arranged on the + Y side or the −Y side from 43. Therefore, the shot area to be exposed on the wafer W is located at a position facing the measurement electrodes 30g, 30i, 30a, 30c, and 30e disposed on the + Y side of the exposure field 43 or on the −Y side of the exposure field 43. The Z position is measured and stored when it is arranged at a position facing the measurement electrodes 30h, 30j, 30b, 30d, and 30f arranged on the surface, and the shot area moves to the exposure field 43 of the projection optical system 7 by scanning. In this case, the Z fine movement mechanism and tilt mechanism in the wafer stage are driven based on the stored Z position measurement value, and the surface of the shot area of the wafer W is set to a predetermined Z position and a predetermined inclination angle. It ’s fine.

Needless to say, such a focusing operation can also be adopted in a scanning exposure type projection exposure apparatus using the local liquid immersion mechanism 8 according to the first embodiment.
In the above embodiment, the center of the exposure field 43 coincides with the optical axis of the projection optical system 7, but these do not necessarily coincide. Particularly when the projection optical system 7 is a catadioptric optical system, the center of the exposure field 43 often does not coincide with the optical axis AX of the projection optical system 7.

  In such a case, as the exposure field 43 is decentered from the optical axis AX of the projection optical system, the center of the exposure light transmission region 42 is also arranged at a position decentered from the optical axis AX of the projection optical system. Accordingly, the measurement electrodes 30a to 30j that are opaque to the exposure light also need to be arranged not symmetrically with respect to the optical axis AX.

  The measurement electrodes 30a to 30j are not limited to materials that are opaque to the exposure light. If a material transparent to the exposure light is used, the measurement electrodes are disposed in the exposure light transmission region 42. It is also possible. It is also possible to dispose the measurement electrode immediately above the exposure field 43.

  When the exposure light is ultraviolet light having a wavelength of 193 nm emitted from an ArF laser, for example, a thin film mainly composed of magnesium oxide as an electrode transparent to the exposure light formed on the surface 40a on the optical member 40 Alternatively, a thin film mainly composed of aluminum oxide can be used. These thin films are transparent to ultraviolet light having a wavelength of 193 nm, and can have sufficient conductivity by mixing an appropriate metal as an impurity. Further, such a thin film can be used as a material for a conductive wire that transmits an electrical signal to the transparent measurement electrode.

  If the thin film that is transparent to the exposure light and has conductivity does not have sufficient corrosion resistance to the liquid that fills the exposure optical path space 31, it constitutes the measurement electrode. A protective layer for protecting the measurement electrode from corrosion may be formed on the surface of the thin film. This protective layer can also be formed on the conducting wire as required.

  This protective layer can also be formed with a predetermined shape and thickness distribution according to the shape of the transparent measurement electrode so as to cancel out the wavefront aberration generated in the exposure light beam by the measurement electrode transparent to the exposure light. It is.

  In the second embodiment, the measurement electrodes 30a to 30j are arranged on the wafer W side surface of the transparent optical member 40 arranged closest to the wafer W among the transparent optical members constituting the projection optical system 7. However, the arrangement of the measurement electrodes 30a to 30j attached to the projection optical system 7 is not limited to this. For example, the measurement electrodes 30a to 30j can be arranged on the hold members 41a and 41b. is there.

In addition, when the transparent optical member closest to the wafer W is inappropriate for the arrangement of the measurement electrodes due to restrictions on the shape and the like, it may be provided on the transparent optical member next to the wafer W.
Next, at least one conductive thin film formed on the wafer W, which is a feature of the present invention, will be described.

  FIG. 5 shows the transparent optical member 40 closest to the wafer W among the transparent members constituting the projection optical system 7 in the vicinity of the local liquid immersion mechanism 8 as shown in FIG. 3 is an enlarged cross-sectional view showing electrodes 30a and 30b and a wafer W. FIG.

  Here, a conductive pattern 51 made of a conductor such as a metal or a semiconductor is formed on the wafer W by a lithography process including a pattern formation process (processing process) such as a previous exposure process and etching. In other portions, a dielectric 50 having electrical insulation is formed. As an example, a dielectric thin film 52 is formed on the upper layer as a film on which a pattern is to be formed by a lithography process including an exposure process using the exposure method of the present invention.

  In the exposure method of the present invention, at least one thin film including a photosensitive film (photoresist) is formed above the dielectric thin film 52 and the like to be patterned, and at least one including the photoresist. At least one of the thin films is a conductive thin film. The conductive thin film is a thin film having electrical conductivity, such as a film made of a conductive organic material, an organic film containing metal fine particles, or a conductive semiconductor thin film.

  The first embodiment of the conductive thin film shown in FIG. 5 is an example in which the photoresist 53 itself applied on the dielectric thin film 52 to be patterned on the wafer W has conductivity. is there. The photoresist having such conductivity is a general resist material for the electron beam exposure technique, and the photoresist 53 used in the present invention also uses the conductive resist for the electron beam exposure technique. It is also possible.

  In the electron beam exposure technique, the conductive resist is mainly used to prevent the resist from being charged due to the electron beam irradiation on the resist and the wafer coated with the resist. In the present invention based on the above, charging due to exposure does not occur, and the purpose of use is naturally different.

  In the present invention, the conductive resist 53 substantially positions the position of the electrode on the wafer W side of the capacitor formed by facing the wafer W and the measurement electrodes 30a, 30c on the conductive resist 53 itself which is a photosensitive film. It is formed to specify.

Hereinafter, this purpose and its effect will be briefly described.
In FIG. 5, if the conductive resist 53 is a normal non-conductive photoresist, the electrode of the capacitor wafer W formed by facing the wafer W and the measurement electrodes 30 a, 30 c is the photoresist 53. Since both the dielectric thin film 52 is a dielectric and has no conductivity, the wafer W itself or the conductive pattern 51, which is a conductive material, is formed.

  As a result, the electrode on the wafer W side of the capacitor formed at the portion where the wafer W and the measurement electrode 30a face each other is substantially a composite of the conductive pattern 51 and the wafer W. The electrode on the wafer W side of the capacitor formed in the portion where the electrode 30c faces is substantially the wafer W, resulting in different electric capacities of both capacitors.

  Therefore, the capacitance of the capacitor formed between the measurement electrode 30a and the like and the wafer W varies depending on the pattern structure formed on the wafer W below the photoresist 53, and the measurement electrode 30a and the like. It is difficult to control (focus control) the photoresist 53 on the wafer W to a predetermined Z position with high accuracy based on the measured capacitance value.

  On the other hand, in the present invention, since the photoresist 53 is the conductive resist 53, the electrode on the wafer W side of the capacitor formed on the portion where the wafer W and the measurement electrode 30a and the measurement electrode 30c face each other is provided. It becomes substantially the surface of the conductive resist 53. The electric capacity of the capacitor is not adversely affected by the pattern structure on the wafer W below the conductive resist 53.

  Therefore, the electric capacities of both capacitors are the areas of the measurement electrode 30a and the measurement electrode 30c, the intervals Da and Dc between the measurement electrode 30a and the measurement electrode 30c and the conductive resist 53, and the portions having the intervals Da and Dc, respectively. It is determined by the dielectric constant of the liquid filled in the exposure optical path space 31 including

  Therefore, in the present invention, by using the conductive resist 53, the conductivity on the wafer W is measured based on the measured values of the capacitance and the like measured by the measurement electrode 30a and the capacitance-type position measurement mechanism control unit 18. It is possible to control the focus resist 53 to a predetermined Z position (focus control) with high accuracy.

  Here, the configuration of the wafer stage 14 for performing the focus control and the configuration of the wafer table 14T on which the wafer W is placed on the wafer stage 14 will be described with reference to FIG.

  FIG. 6A is a top view of the wafer stage 14 and FIG. 6B is a side view of the wafer stage 14. The wafer W is fixed on a wafer table 14T, which is an upper component of the wafer stage 14, by means such as vacuum suction. A portion of the wafer table 14T on which the wafer W is not placed is provided with a cover member TP so that the liquid can be smoothly supplied and recovered in the local liquid immersion mechanism 8 and the liquid may not be inadvertently discharged. The height is set so as to coincide with the surface of the wafer W. For the same purpose, the wafer moving mirror 15 is also set so that its upper end surface coincides with the surface of the wafer W.

  The wafer table 14T is held by the lower structural member 14B of the wafer stage 14 by the three support members AZ1, AZ2, and AZ3. Here, the support members AZ1 to AZ include a piezo element and a leaf spring structure, for example, and have a structure that can be slightly expanded and contracted in the vertical direction (Z direction). With this structure, the wafer table 14T and the wafer W placed thereon can be moved in the Z direction with respect to the lower structural member 14B, and the surface of the supporting member AZ1 to 3 is independently expanded and contracted to the XY plane. It is also possible to incline by a predetermined angle (tilt).

  The support members AZ1 to AZ3 are connected to the main control system 19 and the wafer stage control which are generated based on the measured values of the capacitance and the like measured by the measurement electrode 30a and the capacitance-type position measurement mechanism control unit 18. Based on the command signal from the system 21, the position of the conductive resist (photoresist) 53 on the wafer W is matched with the focal position of the projection image of the pattern on the reticle R by the projection optical system 7. Control the position (focus control).

  Note that it is also possible to perform focus control by providing such a mechanism on the reticle stage 3 instead of the wafer stage 14 and moving the reticle 3 up and down by a small amount and tilting the reticle 3 by a small amount. The focus control can also be performed by moving or tilting a part of the optical member that constitutes the projection optical system 7.

  Note that the conductive pins GP1, GP2, GP3, GP4 provided on the wafer table 14T are not shown in the drawing on the conductive thin film according to the present invention such as the conductive resist 53 formed on the wafer W and the wafer table 14T. It is an electrical contact terminal for providing electrical continuity between the conductor members. This conductor member (not shown) is connected to the capacitance type position measurement mechanism control unit 18 through the lower structural member 14B and the like.

However, it is not necessary to directly connect a conductor member (not shown) to the capacitance type position measurement mechanism control unit 18 as described above, but to connect it to a structural frame (body frame) or the like constituting the projection exposure apparatus,
On the other hand, the conductor member and the capacitance type position measurement mechanism control unit 18 are substantially electrically connected to the capacitance type position measurement mechanism control unit 18 by wiring the lead wire from the structural frame. You can also.

Next, a second embodiment of the conductive thin film of the present invention will be described with reference to FIG.
In this example, the thin film having the conductive thin film is the lower layer thin film 54 formed between the thin film 52 to be patterned and the photoresist 53. The material of the lower layer thin film 54 can also be a conductive organic material, or can be a film containing metal fine particles or a film made of a semiconductor.

  In this example, similarly to the first embodiment of the conductive thin film shown in FIG. 5, when the wafer W is disposed facing the measurement electrodes 30a and 30c, the measurement electrodes 30a and 30c are arranged. The electrode on the wafer W side of the capacitor formed between the wafer W and the wafer W becomes a conductive lower layer thin film 54. Also in the second embodiment, the structure of the dielectric thin film 52 and the conductive pattern 51 which are the structures on the wafer W below the lower layer thin film 54 has no effect on the capacitance of the capacitor. Therefore, it is possible to accurately measure the Z position of the lower layer thin film 54 on the wafer W with respect to the projection optical system 7 and the like using the measurement electrodes 30a and 30c and the like.

  In the second embodiment, since not only the liquid that fills the exposure optical path space but also the photoresist 53 exists between the measurement electrodes 30a and 30c and the capacitor electrodes formed by the lower layer thin film 54, the measurement is performed. The measurement value of the capacitance measured by the electrode 30a and the like and the capacitance type position measurement mechanism control unit 18 includes a correction amount caused by the dielectric constant and thickness of the photoresist 53.

  However, since the dielectric constant and thickness of the photoresist 53 are constant over the entire surface of the wafer W and at least between wafers of the same lot (processing unit), this correction amount is also constant within the above range. doing. Therefore, for example, at the head of the lot, the correction amount is measured by performing a trial exposure, and the target value of the focus control is corrected based on the result, so that highly accurate focus control can be realized. .

  When the thickness of the photoresist 53 and the numerical value of the dielectric constant are known, the correction amount can be obtained as a theoretical value. Therefore, the target value for focus control is based on the theoretical value without performing the above-described trial or the like. Can also be corrected.

Next, an example of a device manufacturing method in the case where the second embodiment of the conductive thin film is employed will be described with reference to FIGS. 7A, 7B, 7C, and 7D. Will be described.
In FIG. 7A, the lower layer thin film 54 which is a conductive thin film is formed between the thin film 52 to be patterned and the photoresist 53 as described above. The lower layer thin film 54 is formed by, for example, spin coating or spray coating, or CVD (Chemical Vapor Deposition). Further, the photoresist 53 is also formed by, for example, coating by spin coating or spray coating.

  A predetermined pattern is projected onto the photoresist 53 by the exposure process using the exposure method according to the present invention. Then, through the development process, as shown in FIG. 7B, a part of the photoresist 53 is removed, and the resist pattern 53p portion remains. In the subsequent etching step (processing step), the lower layer thin film 54 and the dielectric thin film 52 to be processed are patterned using the resist pattern 53p as an etching mask. A cross section of the wafer W in this state is shown in FIG.

  Further, in the removal step, the resist pattern 53p and the lower layer thin film pattern 54p formed on the lower layer thin film 54 are removed, and the patterning of the pattern 52p on the dielectric thin film 52 to be processed is completed as shown in FIG. To do.

A series of processes including the formation of the conductive thin film 54 and the photoresist 53, the exposure process, the development process, the etching process, and the removal process is generally called a lithography process.
In the second embodiment, since the conductive thin film is the lower layer thin film 54 different from the photoresist 53, the photoresist 53 can be selected with the highest priority on imaging performance such as resolution and sensitivity. There is an advantage that a higher-performance photoresist 53 can be used. It is also possible to add, for example, an organic or inorganic pigment that absorbs exposure light to the lower layer thin film 54 and actively utilize it as an antireflection layer. As a result, the imaging performance such as the resolution and the depth of focus of the exposure method of the present invention can be further improved.

  Moreover, the lower layer thin film 54 can also be used as a so-called hard mask. That is, the etching step includes a step of etching the lower layer thin film 54 using the resist pattern 53p as an etching mask, and a step of etching the dielectric thin film 52 to be processed using the lower layer thin film pattern 54p patterned by this etching as an etching mask. It is also possible to employ different etching gases for both etchings.

Thereby, the film thickness of the photoresist 53 can also be reduced, and the resolution and depth of focus of the exposure method of the present invention can be further improved.
On the other hand, the method of making the photoresist 53 itself conductive as in the first embodiment has an advantage that the cost for the entire lithography process can be reduced as compared with the second embodiment.

In the second embodiment, the conductive thin film 54 is not disposed on the uppermost layer on the wafer W. However, the contact portions of the conductive pins GP1 to GP4 shown in FIG. 6 on the wafer W are needle-shaped and pressed against the wafer W with a certain pressing force, so that the conductive pins GP1 to 4 are made to be the uppermost photoresist. It is possible to conduct through the conductive film 54 through 53.

Next, a third embodiment of the conductive thin film of the present invention will be described with reference to FIG.
In this example, the thin film having a conductive thin film is an upper layer thin film 55 formed in an upper layer than the photoresist 53. The material of the upper layer thin film 55 can also be a conductive organic material, or can be a film containing metal fine particles or a film made of a semiconductor. For the formation thereof, application by spin coating or spray coating can be employed.

  Also in the third embodiment, the structure of the dielectric thin film 52 and the conductive pattern 51 which are structures on the wafer W lower than the upper thin film 55 does not affect the capacitance of the capacitor. It is possible to accurately measure the Z position of the upper thin film 55 on the wafer W with respect to the projection optical system 7 and the like using the measurement electrodes 30a and 30c and the like.

  Note that the photoresist 53 to be actually exposed is lower than the upper thin film 55 by the thickness of the upper thin film 55 (on the side closer to the wafer W), but since this thickness is known, this thickness is used for the focus control. High-precision focus control can be realized by correcting the amount of control.

Subsequently, with respect to an example of a device manufacturing method in the case where the third embodiment of the conductive thin film is employed, FIG. 8 (A), FIG. 8 (B), FIG. 8 (C), FIG. 8 (D). Will be described.
In FIG. 8A, the upper layer thin film 55 which is a conductive thin film is formed above the photoresist 53 as described above.

  A predetermined pattern is projected and exposed on the photoresist 53 by an exposure process using the exposure method according to the present invention. Then, in the developing process, the upper thin film 55 is dissolved, and as shown in FIG. 8B, a part of the photoresist 53 is removed, and the resist pattern 53p portion remains. In the subsequent etching, the dielectric thin film 52 to be processed is patterned using the resist pattern 53p as an etching mask. A cross section of the wafer W in this state is shown in FIG.

Then, the resist pattern 53p is removed in the removing step, and the patterning of the pattern 52p on the dielectric thin film 52 to be processed is completed as shown in FIG. 8D.
Also in the third embodiment, since the conductive thin film is the upper thin film 55 different from the photoresist 53, the photoresist 53 can be selected with the highest priority on imaging performance such as resolution and sensitivity. There is an advantage that a higher-performance photoresist 53 can be used. In addition, the thickness and refractive index of the upper thin film 55 can be set to a condition that becomes an antireflection film in relation to the refractive index of the liquid filling the upper layer and the refractive index of the photoresist 53.

Thereby, it is possible to further improve the imaging performance such as the resolution and the depth of focus of the exposure method of the present invention.
Further, when the photoresist 53 is a photoresist sensitive to environmental changes such as a chemically amplified resist, the upper layer thin film 55 can prevent the photoresist 53 from coming into direct contact with the liquid, and the photo by contact with the liquid can be prevented. It is also an advantage of this example that deterioration of sensitivity and resolution performance of the resist 53 can be prevented.

  By the way, for the first embodiment of the conductive thin film of the present invention in which the conductive thin film is the photoresist 53 itself, the device manufacturing method using this was not explained, but in the device manufacturing method in this case, After the development process, the process is the same as in the third embodiment. Therefore, a device can be manufactured by a method similar to the method shown in FIGS. 8B, 8C, and 8D.

In the embodiments of the first to third conductive thin films described above, the electrical conductivity of each conductive thin film is preferably as small as possible. However, as one criterion, the sheet resistance value is approximately 200 Ω / cm ^2. The following is desirable. When the resistance value is larger than this, the conductivity is not sufficient, and the electric capacity measured by the measurement electrode 30a or the like may be affected by the structure on the wafer W below the conductive thin film.

  Note that the capacitance formed between the measurement electrode 30a and the like and the wafer W is inversely proportional to the distance between them as described above. Therefore, in order to measure the change in the interval, it is more convenient to set the interval between them as small as possible. This is because the variation in electric capacity with respect to the variation in distance increases.

  Therefore, in the present invention, the distance between the measurement electrode 30a and the like and the wafer W is preferably set to about 3 mm or less, for example. As the distance between the two increases, the capacitance variation with respect to the distance variation decreases as described above, and the measurement resolution decreases. This is because it is easy to receive measurement errors due to.

  A normal device is formed by performing the above lithography process a plurality of times. However, in the device manufacturing method according to the present invention, an exposure process using the exposure method of the present invention is not necessarily adopted in each of the lithography processes. Needless to say, a part of the film may be formed through an exposure process using the exposure method of the present invention.

  In addition to the lithography process, the device manufacturing method according to the present invention includes a film formation process, an ion implantation process, CVD, plating, or sputtering that forms the dielectric film 52 or semiconductor thin film to be processed by CVD or the like. It may include a step of forming a metal wiring.

  According to the device manufacturing method of this example, since the exposure is performed by the projection method of the above embodiment, it is possible to perform exposure with good focus controllability in the exposure process, and the high resolution of the immersion exposure method can be achieved. It is possible to perform exposure transfer of a sufficiently fine pattern. Accordingly, a highly integrated and high performance semiconductor integrated circuit including a fine pattern can be manufactured at a high yield and at a low cost.

  The exposure method of the present invention can be applied not only to a scanning exposure type projection exposure apparatus but also to a batch exposure type projection exposure apparatus such as a stepper. The magnification of the projection optical system used may be not only a reduction magnification but also an equal magnification or an enlargement magnification.

  Further, the means for realizing the immersion exposure method is not limited to the local immersion type exposure apparatus as described in Patent Document 1 described in the embodiment, but is disclosed in Non-Patent Document 1. In addition, the present invention can also be applied to a whole liquid immersion type exposure apparatus in which the entire wafer is loaded in liquid.

  In the exposure method of the present invention, the focus control of the wafer W can also be performed using the oblique incidence optical position sensor employed in the conventional exposure method. For example, an oblique incident optical position sensor is disposed at the position of the position sensor 13 and the like, and the uneven shape is measured and stored over the entire surface of the wafer W by the oblique incident optical position sensor prior to the exposure process. In the exposure process, focus control can be performed using both the stored value and the measured value of the capacitor capacity formed between the measurement electrode 30a and the wafer W.

  Further, the application of the projection exposure method of the present invention is not limited to the exposure method for manufacturing a semiconductor device using the wafer W described above. For example, a liquid crystal display element or a plasma display formed on a rectangular glass plate The present invention can be widely applied to an exposure method for a display device such as an image pickup device (CCD, etc.), a micromachine, a thin film magnetic head, and various devices such as a DNA chip.

  In addition, this invention is not limited to the above-mentioned embodiment, Of course, a various structure can be taken in the range which does not deviate from the summary of this invention.

  According to the exposure method of the present invention, it is possible to realize a high-resolution exposure method that achieves high-precision focus control even in a so-called immersion exposure method, and sufficiently exhibits the high resolution performance of the immersion exposure method. A projection image of a fine pattern can be projected and exposed on the substrate to be exposed.

  Further, according to the device manufacturing method of this example, since the exposure is performed by the projection exposure method of the above-described embodiment, it is possible to perform exposure with good focus controllability in the exposure process, and the high resolution of the immersion exposure method. It is possible to expose and transfer a fine pattern exhibiting sufficient image properties. Accordingly, a highly integrated and high performance semiconductor integrated circuit including a fine pattern can be manufactured at a high yield and at a low cost.

FIG. 2 is a partially cutaway view showing a schematic configuration of a projection exposure apparatus suitable for use in the exposure method of the present invention. It is an expanded sectional view showing the 1st Example of the local liquid immersion mechanism 8 of the projection exposure apparatus suitable for using for the exposure method of this invention. It is an expanded sectional view showing the 2nd Example of the local liquid immersion mechanism 8 of the projection exposure apparatus suitable for using for the exposure method of this invention. It is a figure showing the measurement electrodes 30a-j formed on the transmission optical member 40 nearest to the wafer W in the projection optical system 7 suitable for use in the exposure method of the present invention. The figure showing the 1st Example (photoresist 53) of the electroconductive thin film on the wafer W by this invention. (A) is a diagram showing a top view of wafer stage 14 of a projection exposure apparatus suitable for use in the exposure method of the present invention, and (B) is a diagram showing a side view of wafer stage 14. (A) is a figure showing the 2nd Example (lower layer thin film 54) of the electroconductive thin film on the wafer W by this invention, (B) is developed in the device manufacturing process using the 2nd Example of the electroconductive thin film. The figure showing the cross section of the wafer W after a process, (C) is the figure showing the cross section of the wafer W after an etching process similarly, (D) is the figure showing the cross section of the wafer W after a removal process. (A) is a figure showing the 3rd example (upper layer thin film 55) of the conductive thin film on wafer W by the present invention, and (B) is developed in the device manufacturing process using the 3rd example of the conductive thin film. The figure showing the cross section of the wafer W after a process, (C) is the figure showing the cross section of the wafer W after an etching process similarly, (D) is the figure showing the cross section of the wafer W after a removal process.

Explanation of symbols

  R ... reticle, W ... wafer, 1 ... light source, 2 ... illumination optical system, 7 ... projection optical system, AX ... optical axis of projection optical system, 8 ... local liquid immersion mechanism, 9 ... liquid supply mechanism, 12 ... recovery mechanism, DESCRIPTION OF SYMBOLS 14 ... Wafer stage, 18 ... Capacitance type position measurement mechanism control part, 19 ... Main control system, 22 ... Upstream rectification member, 23 ... Downstream rectification member, 30a, b ... Measurement electrode, 51 ... Conductive pattern, 52 ... Processing Dielectric film, 53 ... photoresist, 54 ... lower layer thin film, 55 ... upper layer thin film, GP1-4 ... conductive pin

Claims (19)

An exposure method for exposing a pattern on a first object onto a photosensitive film on a second object via a projection optical system,
Forming a thin film of at least one layer including the photosensitive film on the second object;
Filling an optical path space between the thin film on the second object and the projection optical system with a liquid;
The liquid is filled with an electric capacity formed between the measurement electrode attached to or in the vicinity of the projection optical system and the second object on which the at least one thin film is formed. Measuring in the state,
A focus control step of controlling a focus relationship between the first object and the second object via the projection optical system based on the measured value of the capacitance;
In the state where the liquid is filled between the thin film on the second object and the projection optical system, the first object is irradiated with exposure light, and the pattern on the first object is changed to the second object. Including a step of exposing the photosensitive film on the top,
An exposure method, wherein at least one of the at least one thin film including the photosensitive film is a conductive thin film.   The exposure method according to claim 1, wherein the conductive thin film is a film made of an organic material.   The exposure method according to claim 1, wherein the conductive thin film is the photosensitive film.   The exposure method according to claim 1, wherein the conductive thin film is a lower layer thin film formed below the photosensitive film.   The exposure method according to claim 4, wherein the lower layer thin film is an antireflection film that prevents reflection of exposure light used for the exposure.   The exposure method according to claim 1, wherein the conductive thin film is an upper layer thin film formed in an upper layer than the photosensitive film.   The exposure method according to claim 6, wherein the upper thin film is an antireflection film that prevents reflection of the exposure light.   2. The measurement of the capacitance is performed in a state in which a conductive member connected to at least a part of an exposure apparatus used for exposure is in contact with the conductive thin film on the second object. 8. The exposure method according to any one of items 1 to 7.   The exposure method according to claim 1, wherein the focus control step is performed based on the measured value of the electric capacity and a correction amount determined from a configuration of the thin film.   The exposure method according to claim 1, wherein an interval between the measurement electrode and the second object is 3 mm or less.   The exposure method according to claim 1, wherein the measurement electrode is provided on a part of a transmissive optical member constituting the projection optical system.   The measurement electrode is a thin-film electrode formed on the surface of the transmissive optical member that is disposed closest to the second object among the transmissive optical members constituting the projection optical system, on the second object side surface. The exposure method according to claim 11.   The exposure method according to claim 11, wherein the thin film electrode is transparent to the exposure light.   The exposure light according to any one of claims 1 to 13, wherein the exposure light is ultraviolet light having a wavelength of 193 nm, and the thin film electrode is a thin film mainly composed of magnesium oxide or aluminum oxide. Method.   The exposure method according to claim 1, wherein the liquid is water.   The exposure method according to claim 1, wherein the focus control step includes a step of adjusting a position and an angle of the second object with respect to the projection optical system.   17. The exposure process according to claim 1, wherein the exposure step includes a scanning exposure performed while relatively scanning the first object and the second object with respect to the projection optical system. Exposure method. A device manufacturing method including a lithography process,
The exposure which exposes the image of the pattern on the mask as said 1st object to the said photosensitive film | membrane on the to-be-processed substrate which is said 2nd object using the exposure method as described in any one of Claim 1 to 17. Process,
A developing step of developing the photosensitive film after the exposing step;
And a processing step of forming a pattern corresponding to the image of the pattern on the mask on the substrate to be processed based on the pattern made of the photosensitive film formed through the exposure step and the development step. A device manufacturing method. The device manufacturing method according to claim 18, wherein the developing step or the processing step includes a step of removing the conductive thin film.