JP2004163366A - Measuring method, method and apparatus for holding substrate, and aligner - Google Patents

Measuring method, method and apparatus for holding substrate, and aligner Download PDF

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Publication number
JP2004163366A
JP2004163366A JP2002332185A JP2002332185A JP2004163366A JP 2004163366 A JP2004163366 A JP 2004163366A JP 2002332185 A JP2002332185 A JP 2002332185A JP 2002332185 A JP2002332185 A JP 2002332185A JP 2004163366 A JP2004163366 A JP 2004163366A
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Japan
Prior art keywords
substrate
surface
holding
light
holding surface
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Withdrawn
Application number
JP2002332185A
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Japanese (ja)
Inventor
Keikai Harada
継介 原田
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Nikon Corp
株式会社ニコン
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Priority to JP2002332185A priority Critical patent/JP2004163366A/en
Publication of JP2004163366A publication Critical patent/JP2004163366A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate holding apparatus capable of easily acquiring with precision the information regarding a substrate and the shape (planarity) of a holding surface that holds the substrate. <P>SOLUTION: A substrate holder PH holds a photosensitized substrate P, by placing it on a holding surface 1 that holds it. The substrate holder PH comprises a light-transmitting system 67, which is movable relative to a surface PS of the photosensitized substrate P and makes measurement light B irradiated, a light-receiving system 68 which detects a reflected light BB reflected on a rear surface PB facing the surface PS of the photosensitized substrate P, and a controller CONT that detects a contact information between the photosensitized substrate P and the holding surface 1, based on the light quantity of the reflected light BB received by the light-receiving system 68. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a measurement method for measuring a surface state of a substrate, a substrate holding method for holding a substrate, a substrate holding device for holding a substrate, and an exposure apparatus.
[0002]
[Prior art]
A liquid crystal display device or a semiconductor device is manufactured by a so-called photolithography technique of transferring a pattern formed on a mask onto a photosensitive substrate. The exposure apparatus used in this photolithography process has a mask stage that supports a mask and a substrate stage that supports a substrate, and sequentially moves the mask stage and the substrate stage to project a pattern of the mask through a projection optical system. This is to be transferred to a substrate. Among these, when manufacturing a liquid crystal display device, a large glass substrate is used as a substrate, and the mask pattern is continuously scanned while the mask stage and the substrate stage are synchronously scanned due to a demand for a large display area. A scanning type exposure apparatus that transfers data to the upper side is mainly used. In an exposure apparatus, it is necessary to perform exposure processing while keeping the surface (exposed surface) of the glass substrate within the depth of focus of the projection optical system. Therefore, conventionally, when performing the exposure process on the large-sized glass substrate, a plurality of matrix-shaped glass substrate surfaces mounted on the substrate holder of the substrate stage using an oblique incidence reflection type autofocus detection system. A position in the Z-axis direction at the point is detected in advance, surface shape data of the glass substrate is obtained based on the detection result, and the surface position of the glass substrate is within the focal depth of the projection optical system based on the obtained surface shape data. Scanning exposure processing is performed while adjusting the posture of a substrate stage that supports a glass substrate so as to fit.
[0003]
Incidentally, the surface shape of the glass substrate is affected by the shape of the holding surface of the substrate holder that holds the glass substrate. Therefore, it is effective to determine the shape (flatness) of the holding surface of the substrate holder in advance in order to efficiently position the surface of the glass substrate within the above-mentioned depth of focus. Patent Document 1 below discloses a technique for detecting a shape of a holding surface of a substrate holder by detecting light reflected on a back surface of a substrate. Further, Japanese Patent Application Laid-Open No. H11-163873 discloses a technique capable of detecting a front surface position in a wide dynamic range even when reflected light from the back surface is generated when detecting the front surface position of a transparent substrate.
[0004]
[Patent Document 1]
JP 2001-235320 A
[Patent Document 2]
JP-A-5-283316
[0005]
[Problems to be solved by the invention]
The above prior art is a technique in which the shape data of the glass substrate is used as the holding surface shape data of the substrate holder, but the following problems occur.
In other words, the glass substrate tends to undulate (warp or wavy irregularities) as the size increases, but if the glass substrate undulates, the shape of the glass substrate is substituted for the shape of the holding surface of the substrate holder. With this method, an accurate holding surface shape cannot be obtained. Further, the substrate holder has a configuration in which the glass substrate is sucked and held through a large number of suction holes. However, unevenness of the suction causes the glass substrate to undulate, causing the same problem as described above.
[0006]
Further, the substrate holder may be deformed with the passage of time, and when the size of the substrate holder is increased with an increase in the size of the glass substrate, the amount of shape change with the passage of time becomes significant. Therefore, it is necessary to periodically measure the shape of the holding surface of the substrate holder. The measurement of the holding surface shape of the substrate holder may be performed using different glass substrates or in different substrate holding states.If the occurrence of undulation differs between individual glass substrates, or the substrate holding state differs. Good measurement reproducibility cannot be obtained, and the holding surface shape cannot be measured accurately.
[0007]
It is conceivable that the shape of the holding surface of the substrate holder is directly measured by the autofocus detection system without using the shape data of the glass substrate, but as described above, the holding surface of the substrate holder includes many suction holes. Since it has a hole and is subjected to low reflection processing, it is difficult to directly measure the shape of the holding surface of the substrate holder.
[0008]
The present invention has been made in view of such circumstances, and a measurement method, a substrate holding method, and a substrate holding device that can easily and accurately obtain information on the shape (flatness) of a substrate and a holding surface that holds the substrate. And an exposure apparatus.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention employs the following configuration corresponding to FIGS.
The measuring method according to the present invention is directed to a measuring method for placing a substrate (P) on a holding surface (1) holding a substrate (P) and measuring a surface state of the substrate (P). (PS) is irradiated with measurement light (B) relatively movable toward (PS), and based on the amount of reflected light (BB) reflected on the back surface (PB) facing the front surface (PS) of the substrate (P). , A contact state between the substrate (P) and the holding surface (1) is detected.
Further, in the substrate holding method of the present invention, the substrate (P) is placed on a holding surface (1) holding the substrate (P), and the substrate holding method holds the substrate (P). The measurement light (B), which is relatively movable toward the front surface (PS), is irradiated, and based on the amount of reflected light (BB) reflected on the back surface (PB) facing the front surface (PS) of the substrate (P). Thus, the state of contact between the substrate (P) and the holding surface (1) is detected.
A substrate holding device (PH) according to the present invention includes a substrate (P) placed on a holding surface (1) holding a substrate (P), and the substrate holding device (PH) holding the substrate (P). An irradiation section (67) for irradiating the measurement light (B) relatively movable with respect to the front surface (PS) of the substrate, and reflected light reflected on the back surface (PB) opposite to the front surface (PS) of the substrate (P) A light receiving unit (68) for detecting (BB), and a detection for detecting contact information between the substrate (P) and the holding surface (1) based on the amount of reflected light (BB) received by the light receiving unit (68). (CONT).
An exposure apparatus (EX) of the present invention is an exposure apparatus that exposes a pattern on a substrate (P), and includes the above-described substrate holding device (PH) that holds the substrate (P).
[0010]
According to the present invention, for example, when the substrate or the holding surface is deformed such as undulation, a portion where the holding surface is in contact with the substrate (a contact portion) and a portion where the holding surface is not in contact (a non-contact portion) are generated. However, the amount of light reflected from the back surface of the substrate at the contact portion is different from the amount of light reflected from the back surface of the substrate at the non-contact portion. Therefore, the contact state between the substrate and the holding surface is measured by irradiating the surface of the substrate with measurement light while moving the substrate relatively to the substrate, and measuring the amount of reflected light that has passed through the substrate and reflected on the back surface. Can be detected. Then, based on the irradiation position information of the measurement light with respect to the substrate and the detected contact state, the occurrence position information of each of the contact portion and the non-contact portion can be obtained. Based on the obtained occurrence position information, the position of the substrate with respect to the holding surface is determined. Information on the floating state and the shape of the holding surface can be obtained with high accuracy. Specifically, based on the detected contact state and the measured value of the position of the reflected light on the substrate surface corresponding to the contact portion between the substrate back surface and the holding surface, the floating state of the substrate with respect to the holding surface and the holding surface Can be accurately measured.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a substrate holding device and an exposure device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an embodiment of an exposure apparatus provided with the substrate holding device of the present invention, and FIG. 2 is a schematic configuration diagram.
1 and 2, an exposure apparatus EX includes a mask stage MST that supports a mask M on which a pattern is formed, a substrate stage PST that supports a photosensitive substrate P via a substrate holder (substrate holding device) PH, and a mask. An illumination optical system IL that illuminates the mask M supported by the stage MST with the exposure light EL, and a projection that projects an image of the pattern of the mask M illuminated by the exposure light EL onto a photosensitive substrate P supported by the substrate stage PST. The optical system includes an optical system PL, a control device CONT for performing operation control relating to exposure processing, and a storage device MRY connected to the control device CONT. In the present embodiment, the projection optical system PL has a plurality (seven) of projection optical systems PLa to PLg, and the illumination optical system IL also has a plurality (seven) of projection optical systems corresponding to the number and arrangement of the projection optical systems. It has an illumination system module. The photosensitive substrate P is obtained by applying a photosensitive agent (photoresist) to a glass substrate.
[0012]
Here, the exposure apparatus EX according to the present embodiment is a scanning type exposure apparatus that performs scanning exposure by synchronously moving the mask M and the photosensitive substrate P with respect to the exposure light EL, and is a so-called multi-lens scanning type exposure apparatus. Make up. In the following description, the optical axis direction of the projection optical system PL is the Z-axis direction, the direction perpendicular to the Z-axis direction is the synchronous movement direction of the mask M and the photosensitive substrate P, and the X-axis direction (first direction, scanning direction). A direction orthogonal to the Z-axis direction and the X-axis direction is defined as a Y-axis direction (second direction, non-scanning direction). The directions around the X-axis, Y-axis, and Z-axis are defined as θX, θY, and θZ directions.
[0013]
Although not shown, the illumination optical system IL includes a plurality of light sources, a light guide that once collects light beams emitted from the plurality of light sources and then uniformly distributes the light beams, and a uniform illuminance distribution of the light beams from the light guides. An optical integrator for converting the exposure light from the optical integrator into a slit shape, and a condenser lens for imaging the exposure light passing through the blind onto a mask M And Exposure light from the condenser lens illuminates the mask M with a plurality of slit-shaped illumination regions. A mercury lamp is used as a light source in the present embodiment, and g-line (436 nm), h-line (405 nm), and i-line (365 nm), which are wavelengths required for exposure, are exposed by a wavelength selection filter (not shown). Are used.
[0014]
The mask stage MST that supports the mask M is provided so as to be movable, and can perform a long stroke in the X-axis direction for performing one-dimensional scanning exposure and a stroke of a predetermined distance in the Y-axis direction orthogonal to the scanning direction. Have. As shown in FIG. 2, a mask stage driving unit MSTD is connected to the mask stage MST, and the mask stage MST is movable in the X-axis direction and the Y-axis direction by driving the mask stage driving unit MSTD. The mask stage driving section MSTD is controlled by the control device CONT.
[0015]
As shown in FIG. 1, the exposure apparatus EX includes an X laser interferometer 10x that detects a position in the X axis direction of a mask stage MST that supports the mask M, and a Y laser that detects the position in the Y axis direction of the mask stage MST. And an interferometer 10y. An X-moving mirror 11x extending in the Y-axis direction is provided at an end on the −X side of the mask stage MST, and extends in the X-axis direction orthogonal to the X-moving mirror 11x at an end on the −Y side. A movable Y mirror 11y is provided. An X laser interferometer 10x is arranged to face the X movable mirror 11x, and a Y laser interferometer 10y is arranged to face the Y movable mirror 11y. The X laser interferometer 10x irradiates a laser beam to the X movable mirror 11x and detects a distance from the X movable mirror 11x. The Y laser interferometer 10y irradiates a laser beam to the Y moving mirror 11y and detects a distance from the Y moving mirror 11y. The detection results of the laser interferometers 10x and 10y are output to the control unit CONT, and the control unit CONT based on the detection results of the laser interferometers 10x and 10y in the X-axis and Y-axis directions of the mask stage MST (hence, the mask M). Find the position. In addition, by providing a plurality of X laser interferometers (or Y laser interferometers), the amount of rotation of mask stage MST in the θZ direction can be obtained. The control device CONT monitors the position (posture) of the mask stage MST from the outputs of the laser interferometers 10x and 10y, and sets the mask stage MST to a desired position (posture) by controlling the mask stage driving unit MSTD.
[0016]
The exposure light EL transmitted through the mask M is incident on each of the projection optical systems PLa to PLg. The projection optical systems PLa to PLg project and expose a pattern image present in the illumination area of the mask M to the photosensitive substrate P, and are provided corresponding to each illumination system module. As shown in FIG. 1, among the plurality of projection optical systems PLa to PLg, the projection optical systems PLa, PLc, PLe, PLg and the projection optical systems PLb, PLd, PLf are arranged in a staggered manner in two rows. Each of the projection optical systems PLa to PLg transmits a plurality of exposure lights EL emitted from the illumination system module and transmitted through the mask M, and is transmitted to the surface (surface to be exposed) PS of the photosensitive substrate P mounted on the substrate stage PST. The pattern image of the mask M is projected.
[0017]
The substrate stage PST supporting the photosensitive substrate P has a substrate holder PH, and holds the photosensitive substrate P via the substrate holder PH. The substrate stage PST, like the mask stage MST, has a long stroke in the X-axis direction for performing one-dimensional scanning exposure and a long stroke for stepwise movement in the Y-axis direction orthogonal to the scanning direction. As shown in FIG. 2, a substrate stage driving unit PSTD that moves the substrate stage PST in the X-axis direction and the Y-axis direction is provided. The substrate stage driving unit PSTD is controlled by the control device CONT. Further, the substrate stage PST is also movable in the Z-axis direction and in the θX, θY, and θZ directions.
[0018]
As shown in FIG. 1, the exposure apparatus EX includes an X laser interferometer 20x for detecting a position in the X-axis direction of a substrate stage PST supporting the photosensitive substrate P, and a Y for detecting a position in the Y-axis direction of the substrate stage PST. A laser interferometer 20y. An X-moving mirror 21x extending in the Y-axis direction is provided at an end on the -X side of the substrate stage PST, and extends in the X-axis direction orthogonal to the X-moving mirror 21x at an end on the -Y side. A movable Y mirror 21y is provided. An X laser interferometer 20x is arranged facing the X moving mirror 21x, and a Y laser interferometer 20y is arranged facing the Y moving mirror 21y. The X laser interferometer 20x irradiates a laser beam to the X movable mirror 21x and detects a distance from the X movable mirror 21x. The Y laser interferometer 20y irradiates a laser beam to the Y movable mirror 21y and detects a distance from the Y movable mirror 21y. The detection results of the laser interferometers 20x and 20y are output to the control unit CONT, and the control unit CONT based on the detection results of the laser interferometers 20x and 20y, in the X-axis and Y-axis directions of the substrate stage PST (therefore, the photosensitive substrate P). Find the position at. Further, by providing a plurality of X laser interferometers (or Y laser interferometers), the rotation amount of the substrate stage PST in the θZ direction can be obtained. The control device CONT monitors the position (posture) of the substrate stage PST from the outputs of the laser interferometers 20x and 20y, and sets the substrate stage PST to a desired position (posture) by controlling the substrate stage driving unit PSTD.
[0019]
FIG. 3 is a plan view of the substrate holder PH. As shown in FIG. 3, the substrate holder PH has a holding surface 1 for holding the photosensitive substrate P. The photosensitive substrate P is mounted on the holding surface 1. The holding surface 1 is provided with a plurality of suction holes 2 as a chuck mechanism. A plurality of suction holes 2 are uniformly provided on the holding surface 1, and each of the suction holes 2 is connected to a vacuum device (vacuum pump) 3 via a flow path. When the vacuum device 3 is driven, the photosensitive substrate P placed on the holding surface 1 is suction-held by the suction holes 2.
[0020]
The plurality of suction holes 2 are divided into a plurality of areas. In the present embodiment, the plurality of suction holes 2 are divided into four areas AR1 to AR4. A plurality (four) of vacuum devices 3 are provided corresponding to the suction holes 2 provided in each of these areas AR1 to AR4. The number of areas to be divided is not limited to four, but may be any number. The suction operation of each of the plurality of vacuum devices 3 is individually controlled by the control device CONT. The substrate holder PH divides the back surface PB of the photosensitive substrate P into a plurality of parts by the suction holes 2 (vacuum device 3) divided into the plurality of areas AR1 to AR4 and chucks them. The control device CONT can individually control the suction force, the suction speed (the amount of gas sucked per unit time) by each of the vacuum devices 3 (the suction holes 2 for each area), and the timing for starting the suction operation. Therefore, when the photosensitive substrate P is placed on the holding surface 1, the back surface PB of the photosensitive substrate P is suction-held in a different suction state in each of the plurality of areas AR1 to AR4.
[0021]
Further, the substrate holder PH includes lift pins (elevating units) 4 that elevate and lower the photosensitive substrate P with respect to the holding surface 1. The lift pins 4 are provided so as to be able to protrude and retract with respect to the holding surface 1, and are provided so as to be able to ascend and descend while supporting the back (lower) surface PB of the photosensitive substrate P. The lift pins 4 can be arranged in holes 4 </ b> A provided in the holding surface 1. In the present embodiment, the lift pins 4 and the corresponding holes 4A are provided at four positions.
[0022]
FIG. 4 is a schematic view showing the operation of lifting and lowering the lift pins 4. As shown in FIG. 4A, when the lift pins 4 rise above the holding surface 1 while supporting the lower surface of the photosensitive substrate P, the photosensitive substrate P rises above the holding surface 1. On the other hand, as shown in FIG. 4B, the photosensitive substrate P supported by the lift pins 4 is placed on the holding surface 1 by the lift pins 4 being lowered from the holding surface 1 and being arranged in the holes 4A. You.
[0023]
The loading and unloading of the photosensitive substrate P to and from the substrate holder PH are performed via the lift pins 4. When loading the photosensitive substrate P on the substrate holder PH, first, the lift pins 4 are lifted from the substrate holder PH, and a transfer device (not shown) capable of holding and transporting the photosensitive substrate P is provided on the holding surface 1 of the substrate holder PH. The photosensitive substrate P is placed on the tip of the lift pin 4 that has risen higher. Next, the transfer device is retracted from the substrate holder PH. When the lift pins 4 move down, the photosensitive substrate P is held on the holding surface 1 of the substrate holder PH. Here, a suction portion (vacuum suction hole) is provided at the tip of the lift pin 4, and the lift pin 4 suction-holds the lower surface of the photosensitive substrate P. Then, the photosensitive substrate P placed on the holding surface 1 is sucked and held in the suction holes 2. On the other hand, when the photosensitive substrate P is unloaded from the substrate holder PH, the suction to the photosensitive substrate P by the suction holes 2 is released, and the lift pins 4 rise to move the photosensitive substrate P and the holding surface 1 of the substrate holder PH. Separate. Then, the transport device accesses the photosensitive substrate P separated from the substrate holder PH, and moves in the horizontal direction while supporting the lower surface of the photosensitive substrate P, whereby the photosensitive substrate P is unloaded from the substrate holder PH.
[0024]
The holding surface 1 of the substrate holder PH is subjected to a low reflection surface treatment. Specifically, the holding surface 1 is provided with a material layer (film) having low reflectivity, such as black alumite. The low-reflection surface treatment is not limited to black alumite, and a coating made of a black material having low reflectivity or a colored material other than black may be provided. The low-reflection surface treatment may be, for example, a treatment for roughening the holding surface 1 other than providing a film made of a material having low reflectivity. Irradiated light is scattered by forming a rough surface, whereby a low-reflection processing surface composed of a rough surface has lower reflectivity than portions other than the low-reflection processing surface. In the present embodiment, the number of the lift pins 4 and the number of the holes 4A are four, but they can be arbitrarily set as long as the photosensitive substrate P can be moved up and down.
[0025]
Returning to FIGS. 1 and 2, between the projection optical systems PLa, PLc, PLe, PLg and the projection optical systems PLb, PLd, PLf, which are arranged in two rows, face the photosensitive substrate P. A substrate-side autofocus detection system (AF detection system) 60 that detects the position of the photosensitive substrate P in the Z-axis direction; and a mask-side autofocus detection system that faces the mask M and detects the position of the mask M in the Z-axis direction. 70 are provided. A plurality of substrate-side AF detection systems 60 and mask-side AF detection systems 70 are arranged in a plurality in the Y-axis direction. Here, the plurality of substrate-side AF detection systems 60 and the mask-side AF detection systems 70 are unitized by being supported by the housing H as shown in FIG. In the following description, the AF detection systems 60 and 70 and the alignment system AL supported by the housing H will be appropriately referred to as “autofocus unit (AF unit)”.
[0026]
FIG. 5 is a perspective view of the AF unit U. As shown in FIG. 5, a plurality of substrate-side AF detection systems 60 (60a to 60g) are provided in the Y-axis direction which is a non-scanning direction, and in this embodiment, seven are provided side by side. Each of the substrate-side AF detection systems 60a to 60d is arranged at equal intervals in the Y-axis direction. The seven substrate-side AF detection systems 60a to 60g are provided between the projection optical systems PLa, PLc, PLe, and PLg arranged in two rows and the projection optical systems PLb, PLd, and PLf. They are arranged along the direction in which the projection areas of PLg are arranged. The substrate-side AF detection systems 60a to 60g are provided at positions facing the photosensitive substrate P supported by the substrate stage PST, and detect positions in a direction orthogonal to the exposure surface of the photosensitive substrate P, that is, positions in the Z-axis direction. I do.
[0027]
The respective detection results of the substrate-side AF detection systems 60a to 60g are output to the control device CONT, and the control device CONT determines the position of the photosensitive substrate P in the Z-axis direction based on the detection results of the substrate-side AF detection systems 60a to 60g. Ask. Furthermore, since the substrate-side AF detection systems 60a to 60g are two-dimensionally arranged in the Y-axis direction, the control device CONT determines the photosensitive substrate P based on the detection results of the plurality of substrate-side AF detection systems 60a to 60g. The posture in the θX direction can be obtained. By arranging the plurality of substrate-side AF detection systems 60a to 60g so as to be shifted in the X-axis direction, the control device CONT can also obtain the attitude of the photosensitive substrate P in the θY direction. The control device CONT drives the substrate stage driving unit PSTD based on the obtained position in the Z-axis direction and the attitude in the θX (θY) direction, adjusts the position of the photosensitive substrate P in the Z-axis direction, and sets θX (θY (2) Adjust the posture in the direction, that is, perform leveling adjustment.
[0028]
Further, the AF unit U is provided with a plurality of mask-side AF detection systems 70 (70a to 70d). In the present embodiment, four mask-side AF detection systems 70a to 70d are provided. The mask-side AF detection systems 70a to 70d are provided at positions facing the mask M supported by the mask stage MST, and detect positions in a direction orthogonal to the pattern formation surface of the mask M, that is, in the Z-axis direction. . Each of the plurality of mask-side AF detection systems 70a to 70d is arranged at equal intervals in the Y-axis direction.
[0029]
FIG. 6 is a schematic configuration diagram showing the substrate-side AF detection system 60a. The other substrate-side AF detection systems 60b to 60g and the mask-side AF detection systems 70a to 70d have the same configuration as the AF detection system 60a.
As shown in FIG. 6, the AF detection system 60a includes an AF light source 61 composed of an LED that emits the AF measurement light B, a light transmission lens system 62 to which the measurement light B emitted from the light source 61 is incident, The mirror 63 guides the light passing through the optical lens system 62 to the photosensitive substrate P (or the mask M) to be measured from an oblique direction, and the light is generated on the photosensitive substrate P based on the measurement light B irradiated via the mirror 63. A mirror 64 for guiding the reflected light to the light receiving lens system 65 and an image pickup device (CCD) 66 for receiving the light passing through the light receiving lens system 65 are provided. The light-sending lens system 62 irradiates the photosensitive substrate P after shaping the measurement light B into, for example, a slit shape. When the position of the photosensitive substrate P to be measured in the Z-axis direction is displaced by ΔZ, the slit-shaped measurement light emitted from an oblique direction displaces the imaging position of the image sensor 66 in the X-axis direction by ΔX. The imaging signal of the imaging device 66 is output to the control device CONT, and the control device CONT calculates the displacement amount ΔZ of the photosensitive substrate P in the Z-axis direction based on the displacement amount ΔX of the imaging position of the imaging device 66 with respect to the reference position. Here, if the magnification from the incident surface to the exit surface side of the light receiving lens system 65 is set to N times, the imaging device 66 can detect the displacement ΔZ of the photosensitive substrate P with N times sensitivity.
[0030]
In the AF detection system 60a, the light source 61, the light transmission lens system 62, and the mirror 63 constitute a light transmission system (irradiation unit) 67 of the AF detection system, and the mirror 64, the light receiving lens system 65, and the imaging device 66 Constitute a light receiving system (light receiving unit) 68 of the AF detection system. The light receiving system 68 (imaging element 66) can detect information on the imaging position of the measurement light (reflected light) and can also detect information on the light amount of the measurement light (reflected light). Then, by the movement of the substrate stage PST, the light transmission system 67 irradiates the measurement light B from an oblique direction of the incident angle α while relatively moving with respect to the surface PS of the photosensitive substrate P. The measurement light B applied to the photosensitive substrate P is reflected by the front surface PS of the photosensitive substrate P and the back surface PB facing the front surface PS. The light receiving system 68 can receive the reflected light BS on the front surface PS of the photosensitive substrate P and the reflected light BB on the back surface PB. The result of light reception by the light receiving system 68 (image sensor 66) is output to the control unit CONT. The control unit CONT as a detection unit detects contact information between the photosensitive substrate P and the holding surface 1 based on the amount of reflected light BB among the light reception results of the light receiving system 68.
[0031]
Here, the front surface reflected light BS and the back surface reflected light BB are generated at the same time, but by determining the position of incidence on the light receiving system 68 in advance, these reflected lights BS and BB can be determined. Further, since the two reflected lights BS and BB have different intensities (light amounts), they can be easily distinguished.
[0032]
The light source 61 may be provided in each of the plurality of AF detection systems 60a to 60g (70a to 70d), or the light emitted from one light source 61 may be split by a plurality of light guides (optical fibers). A configuration may be employed in which a plurality of branched lights are supplied to each of a plurality of AF detection systems. Further, it is desirable that the AF measurement light is also non-photosensitive to the resist on the photosensitive substrate P, and a filter for cutting light of a specific wavelength out of the light emitted from the light source 61 is provided between the light source 61 and the photosensitive substrate P. It is good also as a structure provided on the optical path between P and.
[0033]
FIG. 7 is a schematic diagram showing measurement points on the photosensitive substrate P by a plurality of substrate-side AF detection systems 60a to 60g provided in the Y-axis direction. The control device CONT moves the substrate stage PST (substrate holder PH) that supports the photosensitive substrate P with respect to the AF unit U in the Y-axis direction, while moving the substrate stage PST (substrate holder PH) in the Y-axis direction of the photosensitive substrate P in each of the AF detection systems 60a to 60g. The AF detection operation is performed at a plurality of points in. Thereby, as shown by "+" in FIG. 7, the measurement points on the photosensitive substrate P by the AF detection systems 60a to 60g, that is, the irradiation positions F1 of the measurement light B on the surface PS of the photosensitive substrate P are set, for example, in a matrix. Is done. Here, the XY coordinates of the irradiation position F1 of the measurement light B are specified based on the detection results of the laser interferometer provided on the substrate stage PST and the installation positions of the plurality of aligned AF detection systems 60a to 60g with respect to the reference positions. . In other words, the position of the reflected light BS on the surface PS of the measurement light B on the XY coordinates is measured by the laser interferometer. Then, a measurement value obtained by measuring the position of the reflected light BS by the laser interferometer is output to the control device CONT.
[0034]
Here, the irradiation position F1 of the measurement light B by the light transmission system 67 of the AF detection system 60 (60a to 60g) or the reflection position G1 (that is, the measurement point) of the measurement light B on the back surface PB described later is the position of the substrate holder PH. It is set to a portion other than the hole (a flat portion of the holding surface 1) such as a suction hole 2 provided on the holding surface 1 and a hole 4A where the lift pins 4 are arranged. That is, the control device CONT sets the irradiation position of the measurement light B based on the shape data on the design value of the holding surface 1 so that the measurement light B is not irradiated to the hole. Thus, the reflected light BB reflected on the back surface PB is reflected toward the light receiving system 68 without being affected by the shape of the hole. The irradiation may be performed continuously, and the measured value of the hole may not be adopted.
[0035]
Next, a method of measuring the surface states of the photosensitive substrate P and the substrate holder PH by the exposure apparatus EX having the above-described configuration will be described with reference to the flowchart of FIG.
First, the photosensitive substrate P is loaded on the substrate holder PH, and the holding surface 1 of the substrate holder PH contacts the back surface PB of the photosensitive substrate P. When the photosensitive substrate P is loaded on the substrate holder PH, the controller CONT drives the vacuum device 3 to attract and hold the photosensitive substrate P on the holding surface 1 of the substrate holder PH under a predetermined suction condition (holding condition) (Step S1). ).
Next, the control device CONT moves the substrate holder PH (substrate stage PST) holding the photosensitive substrate P in the Y-axis direction with respect to the AF unit U, and sends the signals from the light transmitting systems 67 of the AF detection systems 60a to 60g. The measurement light B is irradiated on the surface PS of the photosensitive substrate P from an oblique direction (step S2).
The measurement light B irradiated while relatively moving in the Y-axis direction with respect to the front surface PS of the photosensitive substrate P is reflected by the front surface PS of the photosensitive substrate P and is transmitted through the photosensitive substrate P and reflected by the back surface PB. The front surface reflected light BS reflected on the front surface PS and the back surface reflected light BB reflected on the back surface PB are received by the light receiving system 68 (step S3).
[0036]
Here, when the measurement light B is irradiated while moving relative to the surface PS of the photosensitive substrate P in the Y-axis direction, the amount of the surface reflected light BS received by the light receiving system 68 does not change significantly. When deformation such as undulation occurs on P and the holding surface 1 of the substrate holder PH, the amount of back-surface reflected light BB received by the light receiving system 68 changes. That is, as shown in FIG. 9, based on the deformation of the holding surface 1 of the photosensitive substrate P and the substrate holder PH, the contact portion C1 where the holding surface 1 is in contact with the back surface PB of the photosensitive substrate P is contacted. When a non-contact portion C2, which is a non-contact portion, occurs, the back surface reflected light BB2 (see FIG. 9A) on the back surface PB of the photosensitive substrate P at the non-contact portion C2 and the photosensitive substrate P at the contact portion C1. The amount of light received by the light receiving system 68 is different from that of the back surface reflected light BB1 (see FIG. 9B) on the back surface PB. This is because the light reflectance on the back surface PB of the photosensitive substrate P is different between the contact portion C1 and the non-contact portion C2. That is, the light reflectance on the back surface PB of the photosensitive substrate P at the contact portion C1 is based on the material and the surface state of the substrate holder PH, whereas the light reflectance on the back surface PB of the photosensitive substrate P at the non-contact portion C2. Since the reflectance is based on the gas existing between the back surface PB of the photosensitive substrate P and the holding surface 1 of the substrate holder PH, the light reflectance is different. The controller CONT irradiates the measurement light B to the front surface PS of the photosensitive substrate P while moving the AF detection system 60 relative to the photosensitive substrate P, and transmits the photosensitive substrate P and reflects the back surface reflected light BB reflected by the back surface PB. The contact state between the photosensitive substrate P and the holding surface 1 is detected by measuring the amount of light by the light receiving system 68 (step S4).
That is, the control device CONT irradiates the measurement light B while relatively moving with respect to the photosensitive substrate P, and based on the change in the amount of the back surface reflected light BB, the back surface PB of the photosensitive substrate P and the holding surface 1 of the substrate holder PH. Of the contact portion C1 and the non-contact portion C2 are detected.
[0037]
The control device CONT irradiates the measurement light B and detects the height position (in the Z-axis direction) of the surface PS at each of the irradiation positions F1 detected based on the surface reflected light BS reflected at the irradiation position F1 of the surface PS. Is stored in the storage device MRY in association with the XY coordinates based on the measurement value of the laser interferometer.
Further, the control device CONT associates the height position (the position in the Z-axis direction) of the back surface PB detected based on the back surface reflected light BB with the XY coordinate based on the measurement value of the laser interferometer, and stores the storage device MRY. To memorize.
[0038]
The storage device MRY stores in advance information about the light reflectance on the back surface PB of the photosensitive substrate P at the contact portion C1 and the light reflectance on the back surface PB of the photosensitive substrate P at the non-contact portion C2. . The information on the light reflectance can be obtained in advance by an experiment, for example. The control device CONT can determine the contact portion C1 and the non-contact portion C2 based on the light amount detection result of the back surface reflected light BB of the photosensitive substrate P and the information stored in the storage device MRY. On the other hand, information on the light reflectance can be theoretically obtained based on the material and surface condition (surface roughness) of the holding surface 1 or the material of the photosensitive substrate P.
[0039]
Next, based on the contact state between the photosensitive substrate P and the holding surface 1 determined in step S4, the control device CONT determines the contact ratio, which is the ratio of the contact portion C1 per unit area between the photosensitive substrate P and the holding surface 1 Is obtained (step S5).
In this case, the control device CONT obtains the contact ratio for each of the areas AR1 to AR4.
[0040]
Next, the control device CONT compares the calculated contact rate with a preset threshold value and determines whether the calculated contact rate is equal to or greater than the threshold value (Step S6).
Here, the above-mentioned threshold value is a contact ratio in a state where the substrate stage PST moving for scanning exposure and the photosensitive substrate P are sufficiently attracted and held so as not to cause a positional shift, and are obtained experimentally in advance. Have been. Alternatively, the threshold value is set according to the weight or area of the photosensitive substrate P, or the moving speed (acceleration) of the substrate stage PST during scanning exposure. If the determined contact ratio is equal to or higher than the threshold, the photosensitive substrate P is in a state of being sufficiently held on the holding surface 1, while if the determined contact ratio is equal to or lower than the threshold, The photosensitive substrate P is not sufficiently held on the holding surface 1. Information on the threshold value is stored in the storage device MRY in advance, and the control device CONT compares the determined contact rate with the stored threshold value.
[0041]
If it is determined in step S6 that the contact rate is equal to or less than the threshold value, that is, if the contact state is not good, the control device CONT changes the holding state of the substrate holder PH on the photosensitive substrate P on the holding surface 1 (step S6). S7).
For example, as shown in the schematic diagram of FIG. 10A, when the contact ratio between the photosensitive substrate P and the holding surface 1 is low and the photosensitive substrate P is not in contact with a predetermined amount (a threshold value or more), the control device CONT The suction operation by the suction hole 2 serving as the chuck mechanism is executed again. The re-execution of the suction operation is performed under conditions different from the suction conditions in step S1. Specifically, the suction force or the suction speed for the photosensitive substrate P is changed. Alternatively, the suction operation by the suction holes 2 provided in each of the areas AR1 to AR4 may be set to start at a different timing for each area. Alternatively, the photosensitive substrate P is moved up and down from the holding surface 1 by the lift pins 4 described with reference to FIG. 4, and the mounting operation of the substrate holder PH on the holding surface 1 is performed again. It may be executed.
[0042]
Here, since the suction condition of each of the areas AR1 to AR4 can be individually set, by changing the suction condition of each of the areas AR1 to AR4, the control device CONT can contact the holding surface 1 and the entire photosensitive substrate P. The distribution can be adjusted. The threshold value is set for each of the areas AR1 to AR4, and the contact ratio is individually obtained for each of the areas AR1 to AR4. The controller CONT can make the contact distribution between the holding surface 1 and the entire photosensitive substrate P uniform by setting the respective contact rates of AR4 to AR4 to be equal to or greater than the threshold value. For example, as shown in FIG. 10B, when only a part of the photosensitive substrate P corresponding to the area AR1 is not in contact with the predetermined amount, the suction operation of the suction hole 2 located in the non-contacted area AR1. Only the re-execution may be performed. Of course, even in the state shown in FIG. 10B, the suction operation may be performed again for all the areas AR1 to AR4. In this case, the suction conditions for each of the areas AR1 to AR4 are individually set. Thereby, the control device CONT can set the contact distribution between the photosensitive substrate P and the holding surface 1 uniformly.
[0043]
When the state of holding by the substrate holder PH is changed, the process returns to step S2, and the detection of the state of contact between the photosensitive substrate P and the holding surface 1 is performed again. Then, as shown in FIG. 10C, the processing is repeated until the contact ratio between the photosensitive substrate P and the holding surface 1 becomes equal to or greater than the threshold value for each of the areas AR1 to AR4. Here, the optimum suction force and the suction hole to be used for obtaining the contact rate equal to or higher than the threshold value, that is, the optimum suction condition are stored in the storage device MRY.
[0044]
Although the case where the contact ratio between the photosensitive substrate P and the holding surface 1 is obtained has been described here, a configuration for obtaining the contact area may be used. Then, even if the contact ratio is not equal to or higher than the threshold, if there is a contact portion C1 having a sufficiently large contact area, it may be determined that a good contact state is obtained. The control device CONT compares the threshold value of the contact area with the measured contact area, and adjusts the holding state between the photosensitive substrate P and the holding surface 1.
[0045]
The threshold value is a lower limit value set so as to exert a sufficient holding force on the photosensitive substrate P. However, the holding force (adsorptive force) is too strong or the attraction force distribution is biased. However, even if the threshold value is exceeded, the photosensitive substrate P may be bent. Therefore, the upper limit of the contact rate or the contact area is set in advance, the upper limit is compared with the contact rate (contact area), and based on the comparison result, the contact distribution is determined when the contact rate (contact area) is equal to or less than the upper limit. May be changed so as to make the uniformity.
[0046]
On the other hand, if it is determined in step S6 that the contact ratio is equal to or greater than the threshold, that is, if the contact state is determined to be good, the control device CONT starts measuring the shape of the holding surface 1 of the substrate holder PH. First, the control unit CONT obtains the XY coordinates of the reflection position G1 reflected on the back surface PB of the contact portion C1 when the measurement light B is irradiated on the irradiation position F1 (step S8).
[0047]
FIG. 11 is a diagram showing a positional relationship between the irradiation position F1 of the measurement light B and the reflection position G1 of the contact portion C1 at which the reflected light BB is reflected on the back surface PB.
Here, in the present embodiment, the measurement of the shape of the holding surface of the substrate holder PH is configured to substitute the surface shape of the photosensitive substrate P. However, if it is attempted to obtain the holding surface shape using the height position (position in the Z-axis direction) information of the surface PS corresponding to the non-contact portion C2 (having the same coordinates in the XY coordinates as the non-contact portion C2), the accuracy is high. Satisfactory results cannot be obtained. Therefore, by selectively using only the height position information of the surface PS corresponding to the contact portion C1 (having the same coordinates as the contact portion C1 in the XY coordinates), specifically, having the same XY coordinates as the reflection position G1 The holding surface shape of the substrate holder PH is obtained using the height position information at the position F2 on the surface PS. The control device CONT selectively irradiates the measurement light B only to the surface PS corresponding to the contact portion C1 without irradiating the measurement light B to the surface PS corresponding to the non-contact portion C2, and the surface reflection light BS at this time. The shape of the holding surface is measured based on the result of light reception. The measurement light B may be applied to the surface PS corresponding to the non-contact portion C2, but the height position information obtained at that time may not be stored.
[0048]
The XY coordinates of the irradiation position F1 on the surface PS of the measurement light B irradiated to detect the contact portion C1 are measured by a laser interferometer. In the present embodiment, the measurement light B is applied to the surface PS of the photosensitive substrate P from an oblique direction. The controller CONT obtains the XY coordinates of the contact position G1 between the photosensitive substrate P and the holding surface 1 based on the incident angle of the measurement light B with respect to the surface PS, the thickness of the photosensitive substrate P, and the refractive index of the photosensitive substrate P. Specifically, the control device CONT determines the distance A between the irradiation position F1 of the measurement light B on the front surface PS and the reflection position G1 (that is, the position F2) on the back surface PB, and calculates the distance A from the obtained distance A and the irradiation position F1. The coordinates of the position F2 (G1) are obtained. The distance A is a position where a position F1 where the measurement light B is reflected on the front surface PS and a position G1 where the measurement light B is transmitted through the photosensitive substrate P and reflected on the back surface PB are respectively projected on the holding surface 1 of the substrate holder PH. Relative distance (relative position). And the distance A is
A = t × tan (sin -1 ((Sinα) / n) (1)
Where n is the refractive index of the photosensitive substrate P,
t: thickness of photosensitive substrate P,
α: angle of incidence of measurement light B on photosensitive substrate P,
It is.
The control device CONT corrects the irradiation position F1 of the measurement light B irradiated to obtain the contact portion C1 based on the obtained distance A, and corrects the measurement light B ′ irradiated to measure the shape of the holding surface 1. The irradiation position F2 is obtained.
[0049]
The control device CONT performs the irradiation position correction on each of the plurality of contact portions C1 (reflection positions G1), and sets a plurality of corrected irradiation positions F2. Then, the control device CONT irradiates the measurement light B ′ to each of the plurality of correction irradiation positions F2 which are shifted by the distance A with respect to the irradiation position F1. Specifically, control device CONT moves substrate stage PST stepwise by distance A, and irradiates measurement light B ′. The control device CONT receives the surface reflected light BS of the measurement light B ′ applied to the correction irradiation position F2 by the light receiving system 68, and obtains the height position of each correction irradiation position F2 (step S9).
The controller CONT obtains the position of the reflected light BS at the corrected irradiation position F2 of the surface PS of the measurement light B ′ irradiated at this time in association with the XY coordinates based on the measurement value of the laser interferometer, and performs correction irradiation. Based on the reflected light BS reflected at the position F2, the height position of the surface PS at each of the irradiation positions F2 is stored in the storage device MRY in association with the XY coordinates.
[0050]
The control device CONT determines the contact state at each of the irradiation positions F1 obtained at step S4 and the surface height position at each of the irradiation positions F2 obtained at step S9 among the information stored in the storage device MRY. Based on this, the surface shape of the photosensitive substrate P is determined (Step S10).
The controller CONT obtains the surface shape data by subtracting the inclination component (the inclination of the least square plane) of the obtained shape data, and sets the difference between the obtained maximum value and minimum value as the flatness.
[0051]
Further, the control device CONT determines the surface shape of the photosensitive substrate P based on the surface reflected light BS of the measurement light B radiated to the correction irradiation position F2 measured in step S9, and sets this as the holding surface shape ( Step S11).
That is, the surface shape data derived based on the respective height positions of the correction irradiation position F2 having the same coordinates as the contact portion C1 (reflection position G1) on the surface PS is adopted as the holding surface shape data of the substrate holder PH. Then, the control device CONT obtains holding surface shape data by subtracting the inclination component (inclination of the least square plane) of the obtained shape data, and sets the difference between the obtained maximum value and minimum value as flatness.
[0052]
Further, the control device CONT can determine the floating state of the photosensitive substrate P with respect to the holding surface 1 from the positions of the contact portion C1 and the non-contact portion C2. Alternatively, the control device CONT determines the photosensitivity to the holding surface 1 based on the shape of the holding surface of the substrate holder PH obtained and the height position of the back surface PB obtained in step S4 (or the shape of the substrate surface PS obtained in step S10). The floating state of the substrate P can also be obtained.
[0053]
When the measurement of the surface shape (flatness) of the photosensitive substrate P and the holding surface shape (flatness) of the substrate holder PH is completed, an exposure process is performed while keeping the surface of the photosensitive substrate P within the depth of focus of the projection optical system PL. . Here, when performing the exposure processing while sequentially exchanging the photosensitive substrates P, the holding conditions for the photosensitive substrates P are set based on the optimal suction conditions (optimal holding conditions) set in step S7 and stored in the storage device MRY. Is done. Then, exposure processing is performed in a state where the photosensitive substrate P is held by the substrate holder PH under the optimum holding conditions.
[0054]
When the substrate holder PH is deformed over time, the shape of the holding surface of the photosensitive substrate P is periodically measured. Then, the holding surface shape measurement data acquired periodically is stored in the storage device MRY as holding surface shape history information.
[0055]
As described above, the amount of reflected light BB (BB1) from the back surface PB of the photosensitive substrate P at the contact portion C1, and the amount of reflected light BB (BB2) from the back surface PB of the photosensitive substrate P at the non-contact portion C2 By utilizing this difference, the contact state between the photosensitive substrate P and the holding surface 1 can be detected. Then, the position of the reflected light BS on the surface PS of the measurement light B for detecting the contact state is measured by a laser interferometer, and the coordinates of the contact portion C1 and the non-contact portion C2 are determined based on the measured value. Can be identified. The floating state of the photosensitive substrate P with respect to the holding surface 1 or the shape of the holding surface 1 can be measured based on the contact portion C1 and the non-contact portion C2 whose coordinates are specified.
[0056]
Further, when the holding surface shape of the substrate holder PH is derived using the height position of the substrate surface corresponding to the non-contact portion C2 which is a region floating with respect to the holding surface 1, the holding surface shape cannot be obtained with high accuracy. However, by using the height position of the substrate surface corresponding to the contact portion C1, which is a region held on the holding surface 1, the holding surface shape of the substrate holder PH can be accurately obtained.
[0057]
By setting the threshold value and increasing the contact ratio of the contact portion C1, the substrate holding is stabilized, and the irradiation position F2 (the contact portion C1) which is a measurement point when measuring the shape of the holding surface of the substrate holder PH. Can be increased. Therefore, the holding surface shape measurement can be performed with high accuracy.
[0058]
By periodically measuring the holding surface shape of the substrate holder PH and obtaining the holding surface shape history information, it is possible to estimate the amount of deformation and the shape of the substrate holder PH over time. Therefore, when the flatness of the holding surface 1 of the substrate holder PH measured before the exposure processing is largely different from the estimated shape, for example, dust is interposed between the photosensitive substrate P and the holding surface 1. Alternatively, it can be assumed that the substrate holder PH has been greatly deformed by the action of heat or the like, the cause of the flatness not satisfying the depth of focus can be easily specified, and appropriate treatment can be quickly performed.
[0059]
In this embodiment, the correction irradiation position F2 is obtained from the irradiation position F1 by using the equation (1), and the holding surface shape is obtained based on the reflected light BS of the measurement light B irradiated to the correction irradiation position F2. However, the holding surface shape can be obtained based on the back surface reflected light BB from the reflection position G1 (contact portion C1) without irradiating the measurement light B to the corrected irradiation position F2. On the other hand, as in the present embodiment, by measuring the reflected light at each of the reflection position G1 and the correction irradiation position F2, the substrate surface height position and the holding surface height position at the same coordinates can be obtained. Further, the thickness of the substrate can be obtained by obtaining the difference between the obtained height position of the substrate surface and the height position of the holding surface.
[0060]
When the distance A is constant, the first measurement light and the second measurement light whose relative positions are uniquely determined in advance are applied to the positions F1 and F2, respectively. May be. This eliminates the need for a step moving operation for irradiating the position F2 with the measurement light B after irradiating the position F1 with the measurement light B, thereby improving the throughput.
[0061]
In the present embodiment, the suction operation and the placement operation are re-executed based on the detection result of the contact state between the photosensitive substrate P and the holding surface 1 so that the optimum suction condition is obtained. However, for example, when the contact ratio is low but the contact distribution is almost uniform, the suction force is insufficient, but the occurrence of the bending caused by the suction force distribution of the photosensitive substrate P is suppressed. The exposure process can be performed by, for example, reducing the scanning speed (acceleration) of the substrate stage PST in accordance with the detected contact state. Conversely, if the attraction force or contact distribution on the photosensitive substrate P is very good (a sufficiently large value with respect to the threshold value), the scanning speed (acceleration) can be increased to improve the throughput. it can. That is, it is possible to adopt a configuration in which the exposure processing operation is reset according to the detected contact state.
[0062]
Note that a photosensitive agent layer such as a photoresist is formed on the surface of the photosensitive substrate P, and the thickness of the photosensitive agent layer is usually sufficiently thin (for example, about 1/1000) with respect to the glass substrate as the base material. Therefore, the influence of the photosensitive agent layer on the flatness measurement can be ignored. However, in order to perform more strict flatness measurement, the thickness of the photosensitive agent layer and the refractive index are taken into consideration in the above (1). The formula may be corrected.
[0063]
In this embodiment, the measurement light B and the photosensitive substrate P are relatively moved, and the measurement light B is applied to the photosensitive substrate P, and the contact portion C1 is determined based on a change in the amount of reflected light BB reflected on the back surface PB. And the non-contact portion C2 are obtained, and as described above, the contact portion C1 and the non-contact portion C2 are specified based on the information on the light reflectance previously obtained. Therefore, when the light receiving system 68 receives an amount of light based on an abnormal light reflectance with respect to a previously determined light reflectance, foreign matter or dirt exists between the photosensitive substrate P and the substrate holder PH. Can be detected.
[0064]
Although the chuck mechanism in the present embodiment is the suction hole 2, the present invention is applicable to a pin chuck in which a holding surface is formed using a large number of protrusions having a reduced contact area with the photosensitive substrate P. .
[0065]
Although the exposure apparatus EX in the above embodiment is a so-called multi-lens scan type exposure apparatus having a plurality of projection optical systems adjacent to each other, the present invention also applies to a scanning type exposure apparatus having one projection optical system. Can be applied. Further, as the exposure apparatus EX, in addition to a scanning type exposure apparatus that scans and exposes the pattern of the mask M by synchronously moving the mask M and the photosensitive substrate P, the mask M with the mask M and the photosensitive substrate P stationary. Can be applied to a step-and-repeat type exposure apparatus in which the pattern is exposed and the photosensitive substrate P is sequentially moved stepwise.
[0066]
The application of the exposure apparatus EX is not limited to a liquid crystal exposure apparatus that exposes a liquid crystal display element pattern to a square glass plate, but may be, for example, an exposure apparatus for manufacturing a semiconductor or a thin film magnetic head. It can be widely applied to an exposure apparatus.
[0067]
The light source of the exposure apparatus EX of this embodiment is not only g-line (436 nm), h-line (405 nm) and i-line (365 nm), but also a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), and F 2 A laser (157 nm) can be used.
[0068]
The magnification of the projection optical system PL may be not only the same magnification system but also any of a reduction system and an enlargement system. Further, when far ultraviolet rays such as an excimer laser are used as the projection optical system PL, a material that transmits the far ultraviolet rays such as quartz or fluorite is used as the glass material. 2 When a laser is used, a catadioptric or refractive optical system is used.
[0069]
When a linear motor is used for the substrate stage PST and the mask stage MST, any of an air levitation type using an air bearing and a magnetic levitation type using Lorentz force or reactance force may be used. Further, the stage may be of a type that moves along a guide, or may be a guideless type in which a guide is not provided.
[0070]
When a plane motor is used as the stage driving device, one of the magnet unit and the armature unit is connected to the stage, and the other of the magnet unit and the armature unit is provided on the moving surface side (base) of the stage. Good.
[0071]
The reaction force generated by the movement of the substrate stage PST may be mechanically released to the floor (ground) by using a frame member as described in Japanese Patent Application Laid-Open No. 8-166475. The present invention is also applicable to an exposure apparatus having such a structure.
[0072]
The reaction force generated by the movement of the mask stage MST may be mechanically released to the floor (ground) using a frame member as described in JP-A-8-330224. The present invention is also applicable to an exposure apparatus having such a structure.
[0073]
As described above, the exposure apparatus of the embodiment of the present application provides various subsystems including the components listed in the claims of the present application, so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. It is manufactured by assembling. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from the various subsystems includes mechanical connection, wiring connection of an electric circuit, and piping connection of a pneumatic circuit among the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured. It is desirable that the exposure apparatus be manufactured in a clean room in which the temperature, the degree of cleanliness, and the like are controlled.
[0074]
As shown in FIG. 12, in a semiconductor device, a step 201 for designing the function and performance of the device, a step 202 for manufacturing a mask (reticle) based on the design step, a substrate (wafer, glass plate) serving as a base material of the device, as shown in FIG. ), A substrate processing step 204 of exposing the substrate to a reticle pattern by the exposure apparatus of the above-described embodiment, and developing the exposed substrate. Device assembling steps (including a dicing step, a bonding step, and a package step). ) 205, inspection step 206 and the like.
[0075]
【The invention's effect】
According to the present invention, by utilizing that the amount of reflected light from the back surface of the substrate at the contact portion between the photosensitive substrate and the holding surface is different from the amount of reflected light from the back surface of the substrate at the non-contact portion, The contact state between the substrate and the holding surface can be detected, and based on the detected contact state, information about the floating state of the substrate with respect to the holding surface and the shape of the holding surface can be obtained with high accuracy. In addition, since the shape of the holding surface can be easily obtained and managed, it is possible to efficiently carry out the work for keeping the substrate surface within the depth of focus of the projection optical system during the exposure processing, and if the substrate surface is temporarily within the depth of focus. The cause can be easily specified even if a state that cannot be accommodated occurs.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an embodiment of an exposure apparatus provided with a substrate holding device of the present invention.
FIG. 2 is a schematic side view of FIG.
FIG. 3 is a plan view showing an embodiment of the substrate holding device of the present invention.
FIG. 4 is a schematic view showing an operation of a lifting unit provided in the substrate holding device.
FIG. 5 is a schematic diagram of an AF detection system including an irradiation unit and a light receiving unit.
FIG. 6 is a configuration diagram of an AF detection system.
FIG. 7 is a diagram for explaining an irradiation position of measurement light.
FIG. 8 is a flowchart illustrating an embodiment of a measurement method according to the present invention.
FIG. 9 is a schematic sectional view illustrating a contact state between a substrate and a holding surface.
FIG. 10 is a schematic plan view illustrating a contact state between a substrate and a holding surface.
FIG. 11 is a diagram illustrating correction of a measurement light irradiation position.
FIG. 12 is a flowchart illustrating an example of a semiconductor device manufacturing process.
[Explanation of symbols]
1 ... holding surface, 2 ... suction hole (chuck mechanism), 4 ... lift pin (elevating part),
67: light transmission system (irradiation unit), 68: light reception system (light reception unit), B: measurement light,
BB: Backside reflected light, BS: Frontside reflected light, C1: Contact part, C2: Non-contact part,
CONT: control device, detector, EX: exposure device, P: photosensitive substrate (substrate),
PB ... (substrate) back surface, PH ... substrate holder (substrate holding device),
PS ... (substrate) surface

Claims (12)

  1. Place the substrate on a holding surface holding the substrate, in a measurement method for measuring the surface state of the substrate,
    Irradiating relatively movable measurement light toward the surface of the substrate, and detecting the contact state between the substrate and the holding surface based on the amount of light reflected on the back surface facing the surface of the substrate. A measuring method characterized in that:
  2. The floating state of the substrate with respect to the holding surface is measured based on the detected contact state and a measurement value obtained by measuring a position of the reflected light of the measurement light on the surface. The measurement method described.
  3. The measurement method according to claim 1, wherein the shape of the holding surface is measured based on the detected contact state and a measurement value obtained by measuring a position of the measurement light reflected from the surface. .
  4. Irradiating the measurement light obliquely to the surface of the substrate,
    The incident angle of the measurement light with respect to the surface, the thickness of the substrate, and the contact position between the substrate and the holding surface based on the refractive index of the substrate, with respect to the substrate when measuring the shape of the holding surface The measurement method according to claim 3, wherein the irradiation position of the measurement light is corrected.
  5. Place the substrate on a holding surface for holding the substrate, in a substrate holding method for holding the substrate,
    Irradiating relatively movable measurement light toward the surface of the substrate, and detecting the contact state between the substrate and the holding surface based on the amount of light reflected on the back surface facing the surface of the substrate. A substrate holding method.
  6. The substrate holding method according to claim 5, wherein the holding state of the substrate is changed on the holding surface based on the contact state.
  7. A contact rate or a contact area between the substrate and the holding surface is determined based on the contact state, and the obtained result is compared with a preset threshold value. 7. The substrate holding method according to claim 5, wherein the holding state is changed by:
  8. Place the substrate on a holding surface holding the substrate, in a substrate holding device that holds the substrate,
    An irradiation unit that irradiates a measurement light that can move relatively to the surface of the substrate,
    A light receiving unit that detects reflected light reflected on the back surface opposite to the front surface of the substrate,
    A substrate holding device, comprising: a detection unit that detects contact information between the substrate and the holding surface based on the amount of the reflected light received by the light receiving unit.
  9. A chuck mechanism for chucking the substrate on the holding surface,
    9. The substrate holding apparatus according to claim 8, wherein when the substrate and the holding surface are not in contact with each other by a predetermined amount based on the contact information, chucking of the substrate by the chuck mechanism is performed again.
  10. The holding surface has a chuck mechanism for chucking the substrate by dividing the substrate into a plurality of portions,
    When the substrate and the holding surface are not in contact with each other by a predetermined amount from the contact information, chucking the substrate again in a part of the plurality of portions located in the portion not in contact with the predetermined amount. The substrate holding device according to claim 8, wherein
  11. An elevating unit that elevates the substrate with respect to a holding surface,
    9. The substrate holding apparatus according to claim 8, wherein when the substrate and the holding surface are not in contact with each other by a predetermined amount based on the contact information, the substrate is moved up and down from the holding surface by the elevating unit.
  12. In an exposure apparatus that exposes a pattern to a substrate,
    An exposure apparatus comprising the substrate holding device according to any one of claims 8 to 11, which holds the substrate.
JP2002332185A 2002-11-15 2002-11-15 Measuring method, method and apparatus for holding substrate, and aligner Withdrawn JP2004163366A (en)

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JP2008516229A (en) * 2004-10-06 2008-05-15 インテル コーポレイション Measurement of elastic modulus of dielectric thin film using optical measurement system
JP2009054726A (en) * 2007-08-24 2009-03-12 Nikon Corp Mark detecting method and equipment, position controlling method and equipment, exposing method and equipment, and device manufacturing method
JP2011059489A (en) * 2009-09-11 2011-03-24 Nikon Corp Substrate treatment method and substrate treatment apparatus
JP2011146663A (en) * 2009-04-06 2011-07-28 Canon Inc Substrate holding apparatus, lithography apparatus using the same, and device manufacturing method
KR101258868B1 (en) * 2011-06-02 2013-04-29 아페리오(주) Method and apparatus for photolithography of the chip-embedded printed circuit board
JP2016015371A (en) * 2014-07-01 2016-01-28 ウシオ電機株式会社 Thickness measurement apparatus, thickness measurement method and exposure apparatus
JP2017126011A (en) * 2016-01-15 2017-07-20 株式会社東芝 Exposure apparatus
JP2017530410A (en) * 2014-09-28 2017-10-12 シャンハイ マイクロ エレクトロニクス イクイプメント(グループ)カンパニー リミティド Exposure apparatus, and method for correcting out of focus and tilt error

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008516229A (en) * 2004-10-06 2008-05-15 インテル コーポレイション Measurement of elastic modulus of dielectric thin film using optical measurement system
JP2009054726A (en) * 2007-08-24 2009-03-12 Nikon Corp Mark detecting method and equipment, position controlling method and equipment, exposing method and equipment, and device manufacturing method
JP2011146663A (en) * 2009-04-06 2011-07-28 Canon Inc Substrate holding apparatus, lithography apparatus using the same, and device manufacturing method
US9195129B2 (en) 2009-04-06 2015-11-24 Canon Kabushiki Kaisha Substrate holding device, lithography apparatus using same, and device manufacturing method
JP2011059489A (en) * 2009-09-11 2011-03-24 Nikon Corp Substrate treatment method and substrate treatment apparatus
KR101258868B1 (en) * 2011-06-02 2013-04-29 아페리오(주) Method and apparatus for photolithography of the chip-embedded printed circuit board
JP2016015371A (en) * 2014-07-01 2016-01-28 ウシオ電機株式会社 Thickness measurement apparatus, thickness measurement method and exposure apparatus
JP2017530410A (en) * 2014-09-28 2017-10-12 シャンハイ マイクロ エレクトロニクス イクイプメント(グループ)カンパニー リミティド Exposure apparatus, and method for correcting out of focus and tilt error
US10197923B2 (en) 2014-09-28 2019-02-05 Shanghai Micro Electronics Equipment (Group) Co., Ltd. Exposure device and out-of-focus and tilt error compensation method
JP2017126011A (en) * 2016-01-15 2017-07-20 株式会社東芝 Exposure apparatus

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