JP2011108912A - Exposure device, exposure method, and method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten an operation time by shortening a movement distance of a wafer stage. <P>SOLUTION: A mask stage 14 has a mask stage reference mark 15, and supports a mask 30. A wafer stage 16 is disposed with a certain interval at the mask stage 14 in the optical axis direction of exposure light, and supports a wafer 40. A nano-imprint system 24 can form an alignment mark 44 on the wafer 40. An on-axis camera 20 simultaneously images the mask stage reference mark 15 and alignment mark 44 through a projection optical system 12. A position adjusting device 26 can adjust the position of the wafer stage 16 relative to the mask stage 14, and adjusts the position of the wafer stage 16 based upon image data obtained by imaging the mask stage reference mark 15 and alignment mark 44 by the on-axis camera 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The technology disclosed in this specification relates to an exposure apparatus and an exposure method for projecting a pattern formed on a mask (also referred to as a photomask or a reticle) onto a wafer in a semiconductor manufacturing process.

  For example, Patent Document 1 discloses an exposure apparatus that projects a pattern formed on a mask onto a wafer having a photosensitive film formed on the surface. This type of exposure apparatus includes a mask stage that supports a mask, a wafer stage that supports a wafer, and a projection optical system that reduces light incident through the mask and projects it onto the wafer. The mask stage is provided with a mask stage reference mark, and the wafer stage is provided with a wafer stage reference mark. In this exposure apparatus, the mask stage and the wafer stage are aligned based on the mask stage reference mark and the wafer stage reference mark, and then the pattern is projected onto the wafer.

JP-A-8-279457

  In the above exposure apparatus, in order to acquire information for aligning the wafer stage with respect to the mask stage, a mask stage reference mark formed on the mask stage and a wafer stage reference mark formed on the wafer stage are used. That is, while the mask stage reference mark and the wafer stage reference mark are simultaneously imaged via the projection optical system by the on-axis camera, the position of the wafer stage relative to the mask stage is adjusted so that the two reference marks have a predetermined positional relationship. Then, alignment information of the wafer stage with respect to the mask stage is acquired. Since this on-axis camera uses light of a wavelength that causes the photosensitive film formed on the wafer surface to react, if a wafer stage reference mark is provided on the wafer, the wafer surface photosensitive mark is exposed when the wafer stage reference mark is photographed. Sex membranes react. For this reason, in the conventional exposure apparatus, the wafer stage reference mark is provided outside the portion of the wafer stage where the wafer is supported. As a result, in order to take an image of the wafer stage reference mark, it is necessary to move the wafer stage a long distance with respect to the mask stage, resulting in a problem that the work time is increased accordingly.

  In the present specification, a technique for shortening the working time by shortening the moving distance of the wafer stage relative to the mask stage when aligning the mask stage and the wafer stage is disclosed.

  The technology disclosed in this specification is an exposure apparatus that projects exposure light onto a mask on which a photosensitive film is formed via a projection optical system by irradiating a mask on which the pattern is formed with exposure light. Is embodied as The exposure apparatus includes a mask stage, a wafer stage, a mark forming device, an on-axis camera, a position adjusting device, and a control device. The mask stage includes a mask stage reference mark and supports the mask. The wafer stage is arranged at an interval in the optical axis direction of the exposure light with respect to the mask stage, and supports the wafer. The mark forming apparatus forms alignment marks on the outer peripheral portion of the wafer surface supported by the wafer stage where the semiconductor device is not formed. The on-axis camera is capable of simultaneously imaging the mask stage reference mark and the alignment mark via the projection optical system using light that reacts with the photosensitive film. The position adjusting device can adjust the position of the wafer stage relative to the mask stage. The controller acquires the wafer stage alignment information with respect to the mask stage by adjusting the position of the wafer stage with respect to the mask stage by the position adjustment device while imaging the mask stage reference mark and alignment mark with the on-axis camera.

  In this exposure apparatus, the alignment information between the mask stage and the wafer stage is acquired by using the mask stage reference mark and the alignment mark formed on the wafer surface. Since the alignment mark is formed on the wafer surface, when moving the alignment mark to a position where it can be imaged with an on-axis camera, the wafer stage movement distance relative to the mask stage is set to ON by the conventional exposure apparatus. This is shorter than the moving distance when moving to a position where the image can be captured by the axis camera. As a result, work time can be shortened. Further, the alignment mark is formed on the outer peripheral portion of the wafer surface where the semiconductor device is not formed. For this reason, even if the alignment mark is imaged by the on-axis camera, the photosensitive film in the portion where the semiconductor device is formed is not affected. Furthermore, the alignment mark is formed in a state where the wafer is supported on the wafer stage. For this reason, it is not necessary to form alignment marks on the surface of the wafer before placing the wafer on the wafer stage.

  The exposure apparatus may further include an off-axis camera that can capture an image of the wafer without using a projection optical system using light that does not react with the photosensitive film. In this case, the wafer can be provided with a wafer reference mark on the inner peripheral portion where the semiconductor device is formed, and the mark forming device can be fixed to an off-axis camera. The mark forming apparatus may form the alignment mark when the off-axis camera is aligned with the wafer reference mark.

  According to this configuration, the alignment mark can be formed on the wafer at a position where the off-axis camera is aligned with the wafer reference mark. For this reason, the positional relationship between the wafer reference mark and the alignment mark is the same as the positional relationship between the off-axis camera and the mark forming apparatus. Therefore, it is possible to eliminate the process of aligning the alignment mark while imaging with the off-axis camera. Work time can be shortened.

  In the above exposure apparatus, the controller further adjusts the position of the wafer stage relative to the mask stage with the position adjustment device while imaging the wafer reference mark with the off-axis camera, thereby aligning the wafer reference mark with the off-axis camera. In addition, the alignment mark is formed on the wafer surface at the aligned position, and the position adjustment device uses the wafer stage alignment information with respect to the mask stage and the mark formation device position information with respect to the off-axis camera. The pattern of the mask may be projected onto the wafer by adjusting the position of the wafer stage relative to the mask stage.

  According to this configuration, the mask stage and the wafer stage are aligned based on the alignment information of the wafer stage with respect to the mask stage and the positional relationship between the off-axis camera and the mark forming apparatus, and the mask pattern is aligned with the desired position of the wafer. Can be projected. A wafer on which a desired pattern is projected can be accurately formed.

  Another technique disclosed in this specification is to project the pattern onto a wafer having a photosensitive film formed on the surface via a projection optical system by irradiating a mask on which the pattern is formed with exposure light. Exposure method. In this exposure method, an alignment mark is formed on the outer peripheral portion of the wafer surface supported by the wafer stage where the semiconductor device is not formed, and an on-axis camera is used to adjust the position of the wafer stage while adjusting the position of the wafer stage relative to the mask stage. And a step of aligning the mask stage and the wafer stage by imaging the mask stage reference mark and the alignment mark.

  According to this method, the movement distance of the wafer stage relative to the mask stage when aligning the wafer stage with respect to the mask stage can be made shorter than before, and the working time can be shortened.

  Also, a method for manufacturing a semiconductor device having an exposure process by the above exposure method is novel and useful.

FIG. 1 illustrates a configuration of an exposure apparatus and an exposure method (1). FIG. 2 illustrates an exposure method (2). FIG. 3 illustrates an exposure method. FIG. 4 illustrates an exposure method (4). FIG. 5 illustrates an exposure method (5).

The technical features of the embodiments described below are listed.
(Mode 1) A nanoimprint apparatus is used as a mark forming apparatus.
(Mode 2) The on-axis camera irradiates the imaging target with exposure light of λ = 365 nm.
(Mode 3) The off-axis camera irradiates the imaging target with halogen lamp light of λ = 590 ± 60 nm.
(Mode 4) The alignment mark is formed on a photoresist film applied to the wafer surface. For this reason, the time from when the exposure light is irradiated by the on-axis camera to when the reading becomes possible can be shortened.
(Mode 5) The alignment mark is formed on the outer peripheral portion of the wafer surface where the pattern is not projected. Therefore, even if the photoresist around the alignment mark is exposed by irradiating the exposure light with the on-axis camera, the projection of the pattern is not affected.
(Mode 6) The mask includes a mask reference mark. The mask and the mask stage are aligned by aligning the mask reference mark and the mask stage reference mark.

  Embodiments will be described with reference to the drawings. FIG. 1 shows an outline of the configuration of the exposure apparatus 2 of the present embodiment. The exposure apparatus 2 is used as an apparatus for manufacturing a semiconductor device. A pattern (circuit pattern, element pattern, wiring pattern, etc.) formed on the mask 30 is reduced by the projection optical system 12, and the reduced pattern is formed on the wafer 40. Project. The exposure apparatus 2 of the present embodiment is a projection exposure apparatus (stepper) that projects the pattern of the mask 30 onto a plurality of locations on the wafer 40 while fixing the mask 30 and moving the wafer 40 intermittently. The exposure apparatus 2 includes a light source 10, a projection optical system 12, a mask stage 14, a wafer stage 16, a control unit 18, an on-axis camera 20, an off-axis camera 22, a nanoimprint apparatus 24, and a position adjustment apparatus. 26. A mask 30 is supported on the mask stage 14. A wafer 40 is supported on the wafer stage 16.

  The light source 10 irradiates light having a wavelength with which a photoresist (photosensitive agent) applied to the surface of the wafer 40 reacts. As the light source 10, for example, a high-pressure mercury lamp, an excimer laser, other laser devices, or the like can be used. The exposure light 100 emitted from the light source 10 is reflected by the reflection mirrors 11a and 11b provided in the vicinity of the light source 10, and is applied to the mask 30 supported by the mask stage 14 (see FIG. 5). The exposure light 100 applied to the mask 30 is applied to the wafer 40 via the projection optical system 12 (see FIG. 5).

  The mask stage 14 is disposed between the light source 10 and the projection optical system 12. The mask stage 14 has an opening at the center thereof, and supports the peripheral edge of the mask 30 at the peripheral edge of the opening. The exposure light 100 irradiated to the mask 30 from the light source 10 enters the projection optical system 12 through the opening of the mask stage 14 (see FIG. 5). A mask stage reference mark 15 is formed on the mask stage 14 as a reference for adjusting the position of the mask stage 14 and the mask 30 and adjusting the position of the mask stage 14 and the wafer stage 16. The mask stage reference mark 15 can be imaged by the on-axis camera 20 described above. The mask stage 14 is fixed to a frame (not shown) so that the positional relationship with the light source 10 and the projection optical system 12 does not fluctuate.

  The mask 30 is supported on the mask stage 14 described above (see FIGS. 4 and 5). The mask 30 is usually formed of a glass plate. A circuit pattern or the like according to a desired semiconductor device is formed on the mask 30, and a mask reference mark 32 for adjusting the position of the mask 30 and the mask stage 14 is formed. The mask reference mark 32 can also be imaged by the on-axis camera 20 described above. When the exposure light 100 is irradiated onto the mask 30, the pattern formed on the mask 30 is projected onto the surface of the wafer 40 via the projection optical system 12.

  A mask adjustment mechanism 34 that adjusts the position of the mask 30 on the mask stage 14 is provided in the vicinity of the mask stage 14. For the mask adjustment mechanism 34, for example, an arm robot or the like is used.

  The projection optical system 12 is disposed below the mask stage 14 (in the Z-axis direction in FIG. 1). The Z-axis direction in this embodiment refers to a direction (vertical direction) parallel to the optical axis 100a of the exposure light 100 (see FIG. 5) projected from the mask 30 onto the wafer 40, as shown in FIG. Further, the X-axis direction and the Y-axis direction indicate directions (horizontal directions) orthogonal to each other in a plane perpendicular to the Z-axis direction, and the rotation axis direction indicates a rotation direction around the Z axis. The projection optical system 12 is composed of a plurality of lenses 50, and projects the light incident through the mask 30 on the wafer 40 by reducing it. For example, the projection optical system 12 includes a plurality of lenses 50 so that a circuit pattern formed on the mask 30 is reduced to 1/4 times, 1/5 times, or 1/10 times and projected onto the wafer 40. It is arranged.

  The wafer stage 16 is disposed below the projection optical system 12 (in the Z-axis direction in FIG. 1) and faces the mask stage 14 with the projection optical system 12 interposed therebetween. The wafer stage 16 supports the wafer 40 on its upper surface. The exposure light 100 applied to the mask 30 is projected onto the wafer 40 supported by the wafer stage 16 through the mask 30 and the projection optical system 12 (see FIG. 5). The wafer stage 16 is connected to a position adjusting device 26. The position adjusting device 26 is connected to the control unit 18, and moves the wafer stage 16 in the X axis direction, the Y axis direction, the Z axis direction, and the rotation axis direction (around the Z axis) in accordance with a drive control command from the control unit 18. To drive. Driving information of the wafer stage 16 by the position adjusting device 26 (position information (rotation angle of a motor or the like)) is input to the control unit 18. The control unit 18 can calculate the position of the wafer stage 16 based on the drive information from the position adjustment device 26.

  The wafer 40 supported on the wafer stage 16 described above is a substrate onto which the pattern of the mask 30 is projected. A wafer reference mark 42 for specifying the positional relationship between the wafer 40 and the wafer stage 16 is formed on the wafer 40. In this embodiment, the wafer reference mark 42 is imaged by the off-axis camera 22 described above. Photoresist is applied to the surface of the wafer 40 to form a photoresist film. The wafer reference mark 42 is formed in a portion of the wafer 40 where the pattern of the mask 30 is projected by the exposure light 100. The wafer reference mark 42 is formed under the photoresist film. Various photoresists used in the semiconductor manufacturing process can be used as the above-described photoresist, and the physical properties are changed by projecting the exposure light 100, and the surface of the material is protected from subsequent processing such as etching. Have. In the present embodiment, the properties of the photoresist (positive type or negative type) are not limited.

  The on-axis camera 20 includes an unillustrated light source and an imaging device, and is an apparatus that obtains an image by irradiating the imaging target with light and receiving light reflected from the imaging target. As shown in FIG. 3, the on-axis camera 20 captures an imaging target via the projection optical system 12. Therefore, a light source that can emit light having the same wavelength as the light source 10 for exposure is used as the light source of the on-axis camera 20. In this embodiment, a laser device such as a high-pressure mercury lamp is used as the light source of the on-axis camera 20. The on-axis camera 20 of the present embodiment can irradiate the imaging target with exposure light (i-line) of λ = 365 nm. Moreover, as an imaging device of the on-axis camera 20, for example, a photoelectric conversion element such as a CCD element can be used. In the present embodiment, the on-axis camera 20 is disposed above the mask stage 14. As shown in FIG. 3, the optical axis 20 a of the irradiation light of the on-axis camera 20 is irradiated to the peripheral portion of each lens 50 of the projection optical system 12, so that it is refracted by passing through each lens 50. The on-axis camera 20 can simultaneously image an alignment mark 44 (described later) formed on the wafer 40 and a mask stage reference mark 15 via the projection optical system 12 (see FIG. 3). Further, the on-axis camera 20 can simultaneously capture the mask reference mark 32 and the mask stage reference mark 15 (see FIG. 4). In this case, the on-axis camera 20 images the mask reference mark 32 and the mask stage reference mark 15 without using the projection optical system 12. An image captured by the on-axis camera 20 is output to the control unit 18.

  Similarly to the on-axis camera 20, the off-axis camera 22 includes an unillustrated light source and an imaging device, and irradiates the imaging target with light and receives light reflected from the imaging target to obtain an image. is there. As shown in FIG. 1, the off-axis camera 22 captures an imaging target without using the projection optical system 12. Therefore, the light source of the off-axis camera 22 may be one that can emit light of any wavelength that does not react with the photoresist (photosensitive agent) on the surface of the wafer 40. In the present embodiment, for example, a halogen lamp is used as the light source of the off-axis camera 22. For this reason, the off-axis camera 22 can irradiate halogen lamp light of λ = 590 ± 60 nm. As the imaging device of the off-axis camera 22, for example, a photoelectric conversion element such as a CCD element can be used. In this embodiment, the off-axis camera 22 is disposed on the side of the projection optical system 12, that is, at a position deviated from the optical axis 100 a of the exposure light 100 and above the wafer stage 16. In this embodiment, the off-axis camera 22 can image the wafer reference mark 42 formed on the wafer 40 without using the projection optical system 12. An image captured by the off-axis camera 22 is output to the control unit 18.

  The nanoimprint apparatus 24 is an apparatus that creates alignment marks 44 on the photoresist film on the surface of the wafer 40. The nanoimprint apparatus 24 is fixed to the side of the off-axis camera 22 described above. As illustrated in FIG. 2, the nanoimprint apparatus 24 includes a UV light irradiation unit 54 that is a main body, and an original plate 56 that is accommodated in the UV light irradiation unit 54. The UV light irradiation unit 54 includes a light source (not shown) that emits UV light, and can irradiate the original 56 with UV light. When forming the alignment mark 44, the nanoimprint apparatus 24 can advance the original plate 56 from the lower end of the UV light irradiation unit 54 toward the wafer 40 and abut the lower end surface thereof on the surface of the wafer 40. A pattern 58 is formed on the lower end surface of the original 56. As shown in FIG. 2, the lower surface of the original 56 comes into contact with the original 56 by irradiating the original 56 with UV light while the lower surface of the original 56 is in contact with the surface of the wafer 40. The pattern 58 of the original 56 can be transferred to the photoresist. As a result, an alignment mark 44 having a shape corresponding to the pattern 58 is formed on the photoresist film on the surface of the wafer 40. In the nanoimprint apparatus 24, each operation such as advancement and accommodation of the original 56 and irradiation of UV light from the UV light irradiation unit 54 to the original 56 is performed according to a signal from the control unit 18.

  The alignment mark 44 is formed by the nanoimprint apparatus 24 at a position where the off-axis camera 22 is aligned with the wafer reference mark 42 without moving the wafer stage 16 (see FIGS. 1 and 2). Since the nanoimprint apparatus 24 is fixed to the off-axis camera 22, the positional relationship between the nanoimprint apparatus 24 and the off-axis camera 22 is predetermined and known. Therefore, when the alignment mark 44 is formed at the position where the off-axis camera 22 images the wafer reference mark 42, the positional relationship between the wafer reference mark 42 and the alignment mark 44 is the same as the positional relationship between the off-axis camera 22 and the nanoimprint apparatus 24. It becomes. Thus, in this embodiment, the step of aligning the alignment mark 44 with respect to the off-axis camera 22 can be omitted.

  In this embodiment, the alignment mark 44 formed by the nanoimprint apparatus 24 is radially outward from the wafer reference mark 42 when viewed from the center of the wafer 40, and the exposure light 100 (see FIG. 5). Thus, the pattern is formed on a portion where the pattern is not projected. Therefore, even if the photoresist around the alignment mark 44 is exposed by the exposure light of the on-axis camera 20, the projection of the pattern of the mask 30 by the exposure light 100 performed thereafter is not affected. The alignment mark 44 is formed on the photoresist film on the surface of the wafer 40. Therefore, the on-axis camera 20 is compared with the case where an alignment mark is formed in advance on the outer peripheral portion of the wafer 40 (the portion where the pattern is not projected by the exposure light 100) and a photoresist film is formed on the surface of the wafer 40. This shortens the time until the alignment mark can be read. That is, when an alignment mark is formed below the photoresist film, in order to photograph the alignment mark, the photoresist film above the alignment mark must be exposed. For this reason, a certain amount of time is required until the alignment mark can be photographed. However, in this embodiment, since the alignment mark 44 is formed on the surface of the photoresist film, such time is not required.

  The control unit 18 includes a CPU and a storage unit (not shown) and controls the operation of the exposure apparatus 2. The control unit 18 is connected to the light source 10, the position adjustment device 26, the mask position adjustment mechanism 34, the on-axis camera 20, the off-axis camera 22, and the nanoimprint device 24. 1 to 5, illustration of wiring between the control unit 18 and each of the above devices is omitted. The controller 18 receives drive information from the position adjustment device 26 and image data from the on-axis camera 20 and the off-axis camera 22. The control unit 18 controls the light source 10, the position adjustment device 26, the mask position adjustment mechanism 34, the nanoimprint device 24, and the like based on various types of input information.

  The configuration of the exposure apparatus 2 according to the present embodiment has been described in detail above. Hereinafter, an example of a method for adjusting the positions of the mask 30 and the wafer 40 and projecting the pattern of the mask 30 onto the wafer 40 in the exposure apparatus 2 of the present embodiment will be described with reference to FIGS. .

  As shown in FIG. 1, first, the control unit 18 captures the surface of the wafer 40 with the off-axis camera 22 while the wafer reference mark 42 is captured in a predetermined position (for example, an image captured by the off-axis camera 22). The position adjusting device 26 is driven so as to be at the center of the image, and the wafer stage 16 is positioned.

  Next, as illustrated in FIG. 2, the control unit 18 activates the nanoimprint apparatus 24 without moving the wafer stage 16 from the position where the wafer reference mark 42 is aligned with respect to the off-axis camera 22. The nanoimprint apparatus 24 advances the original 56 toward the wafer 40 and brings the lower end surface of the original 56 into contact with the surface of the wafer 40. Next, the UV light irradiation unit 54 irradiates the original 56 with UV light. With this UV light irradiation, the alignment mark 44 corresponding to the pattern 58 formed on the lower end surface of the original 56 is radially outside the wafer reference mark 42 when viewed from the center of the wafer 40 and is exposed. A pattern is formed on the outer peripheral portion where the pattern is not projected by the light 100 (see FIG. 5). The alignment mark 44 is formed on the photoresist film on the surface of the wafer 40. Since the nanoimprint apparatus 24 is fixed to the off-axis camera 22, the positional relationship between the wafer reference mark 42 and the alignment mark 44 is the same as the positional relationship between the off-axis camera 22 and the nanoimprint apparatus 24.

  Next, as shown in FIG. 3, the control unit 18 captures the mask stage reference mark 15 and the alignment mark 44 in the image captured by the on-axis camera 20 while capturing the surface of the wafer 40 with the on-axis camera 20. The position adjustment device 26 is driven so as to achieve the positional relationship (for example, the positional relationship in which both marks overlap), and the wafer stage 16 is positioned. The control unit 18 detects positional information of the wafer stage 16 when the mask stage reference mark 15 and the alignment mark 44 are in a predetermined positional relationship in the image photographed by the on-axis camera 20 (that is, the wafer stage relative to the mask stage 14). 16 position information) is calculated and stored. This position information is calculated based on drive information input from the position adjustment device 26.

  Next, as shown in FIG. 4, the control unit 18 activates the mask adjustment mechanism 34. The mask adjustment mechanism 34 places the mask 30 on the mask stage 14 using an arm (not shown). The controller 18 simultaneously images the mask reference mark 32 of the placed mask 30 and the mask stage reference mark 15 of the mask stage 14 with the on-axis camera 20. Image data captured by the on-axis camera 20 is input to the control unit 18. Based on the image data input from the on-axis camera 20, the control unit 18 drives the mask adjustment mechanism 34 so that the positions of the mask reference mark 32 and the mask stage reference mark 15 in the image data match. The controller 18 stops driving the mask adjustment mechanism 34 at a position where the positions of the mask reference mark 32 and the mask stage reference mark 15 coincide. As a result, the mask 30 and the mask stage 14 are aligned.

  Next, as shown in FIG. 5, the control unit 18 drives the position adjusting device 26 so that the wafer 40 is positioned at a predetermined position while monitoring the rotation angle of the motor built in the position adjusting device 26. . The predetermined position here means the position of the wafer 40 for projecting the pattern formed on the mask by irradiating the exposure light. The predetermined position of the wafer 40 for projection is stored in advance in the control unit 18 as a relative position with respect to the wafer reference mark 42. Here, the positional relationship between the wafer reference mark 42 and the alignment mark 44 has been acquired, and the positional relationship between the alignment mark 44 and the mask stage reference mark 15 has also been acquired. Therefore, the positional relationship between the wafer reference mark 42 and the mask stage reference mark 15 can be specified, and the pattern of the mask 30 can be projected to a desired position based on the specified positional relationship. Note that the wafer 40 of this embodiment has a plurality of areas for projecting patterns, and the control unit 18 stores the relative positions of the respective areas. Based on the positional relationship between the specified wafer reference mark 42 and the mask stage reference mark 15, the control unit 18 calculates a position for positioning the wafer stage 16 for each region. Then, the controller 18 positions the wafer stage 16 at the calculated position, thereby positioning the wafer 40 so that the exposure light 100 for projecting the pattern is in focus at a desired position for projecting the pattern of the mask 30. can do.

  Next, the control unit 18 drives the light source 10 to generate the exposure light 100. As a result, the exposure light 100 is applied to the mask 30 supported by the mask stage 14 via the reflection mirrors 11a and 11b. By irradiating the mask 30 with the exposure light 100, the pattern of the mask 30 is emitted toward the projection optical system 12. The emitted pattern is reduced through the projection optical system 12 and irradiated onto the wafer 40. Thereby, the pattern of the mask 30 is projected onto the wafer 40. Further, the control unit 18 drives the position adjusting device 26 to repeat the positioning of the wafer 40 and the driving of the light source 10, thereby obtaining the wafer 40 on which a desired pattern is projected.

  As is apparent from the above description, the nanoimprint apparatus 24 of this embodiment corresponds to the mark forming apparatus described in the claims. Further, the photoresist film of this example corresponds to the photosensitive film described in the claims.

  According to the exposure apparatus 2 of the present embodiment, the alignment mark 44 formed on the wafer 40 and the mask stage reference mark 15 are imaged by the on-axis camera 20, thereby aligning the mask stage 14 and the wafer stage 16. . Therefore, the movement distance of the wafer stage 16 when the alignment mark 44 is moved to a position where the on-axis camera 20 can image the wafer stage reference mark provided on the wafer stage in the conventional exposure apparatus is imaged by the on-axis camera. This is shorter than the moving distance of the wafer stage when moving to a possible position. Further, the movement distance of the wafer stage 16 when the wafer 40 is moved to a desired pattern projection position after the alignment of the mask stage 14 and the wafer stage 16 can be shortened. Therefore, work time can be shortened.

  Further, according to the exposure apparatus 2 of the present embodiment, the nanoimprint apparatus 24 is fixed to the off-axis camera 22, and thus is formed by the imaging position of the off-axis camera 22 (position of the wafer reference mark 42) and the nanoimprint apparatus 24. The positional relationship with the position where the alignment mark 44 is formed is predetermined and known. Therefore, it is not necessary to re-align the alignment mark 44 formed by the nanoimprint apparatus 24 with the off-axis camera 22 and align the off-axis camera 22 with the alignment mark 44. Work time can be shortened.

The modifications of the above embodiment are listed below.
(1) Although the exposure apparatus 2 of the above embodiment is a projection exposure apparatus (stepper) that fixes the mask 30 and exposes the pattern of the mask 30 onto the wafer 40, the exposure apparatus 2 is not limited to a stepper. Therefore, for example, a projection exposure apparatus (aligner) that fixes the mask stage 14 and the wafer stage 16 and exposes the pattern of the mask 30 onto the wafer 40 may be used. Alternatively, a scanning projection exposure apparatus (scanner) that exposes the pattern of the mask 30 onto the wafer 40 while the mask stage 14 and the wafer stage 16 are moved synchronously with each other may be used.

  (2) In the above embodiment, the projection optical system 12 is composed of a plurality of lenses 50 having a fixed magnification. However, the projection optical system 12 may be composed of a plurality of lenses 50 capable of changing the magnification. Good. Alternatively, a single lens 50 may be used.

  (3) In the above embodiment, the mask stage 14 is fixed, but the mask stage 14 can be driven in the vertical direction, the horizontal direction, and the rotation axis direction (around the Z axis) by a driving device such as a motor. It may be configured.

  (4) Although the alignment mark 44 is formed at the position where the off-axis camera 22 and the wafer reference mark 42 are aligned in the above embodiment, the step of aligning the off-axis camera 22 and the alignment mark 44 is omitted. The technique of the present application is not limited to such a form. The alignment mark 44 may be formed at any position on the outer periphery of the wafer 40. In this case, the off-axis camera 22 and the alignment mark 44 are aligned, and position information of the alignment mark 44 with respect to the off-axis camera 22 is acquired. Thereby, the positional relationship between the wafer reference mark 42 and the alignment mark 44 can be specified.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  Further, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: exposure apparatus, 10: light source, 11a, 11b: reflection mirror, 12: projection optical system, 14: mask stage, 15: mask stage reference mark, 16: wafer stage, 18: control unit, 20: on-axis camera, 22: Off-axis camera, 24: Nanoimprint apparatus, 26: Position adjustment apparatus, 30: Mask, 32: Mask reference mark, 34: Mask adjustment mechanism, 40: Wafer, 42: Wafer reference mark, 44: Alignment mark, 50: Lens, 52: Mask stage reference mark, 54: UV light irradiation part, 56: Original, 58: Pattern, 100: Exposure light

Claims (5)

An exposure apparatus for projecting the pattern onto a wafer having a photosensitive film formed on a surface via a projection optical system by irradiating exposure light onto a mask on which a pattern is formed,
A mask stage, a wafer stage, a mark forming device, an on-axis camera, a position adjusting device, and a control device;
The mask stage includes a mask stage reference mark and supports the mask,
The wafer stage is arranged at an interval in the optical axis direction of exposure light with respect to the mask stage, and supports the wafer,
The mark forming apparatus forms an alignment mark on an outer peripheral portion of the surface of the wafer supported by the wafer stage where a semiconductor device is not formed,
The on-axis camera is capable of simultaneously imaging the mask stage reference mark and the alignment mark via the projection optical system using light that reacts with the photosensitive film.
The position adjustment device is capable of adjusting the position of the wafer stage relative to the mask stage,
The control device adjusts the position of the wafer stage with respect to the mask stage by the position adjustment device while imaging the mask stage reference mark and the alignment mark with the on-axis camera, so that the wafer stage with respect to the mask stage is adjusted. Get alignment information for
An exposure apparatus characterized by that. Using light that does not react with the photosensitive film, further comprising an off-axis camera capable of imaging the wafer without going through the projection optical system;
The wafer includes a wafer reference mark on an inner peripheral portion where a semiconductor device is formed,
The mark forming device is fixed to the off-axis camera,
The mark forming device forms an alignment mark when the off-axis camera is aligned with the wafer reference mark;
The exposure apparatus according to claim 1, wherein: The control device further includes:
While aligning the wafer reference mark with respect to the off-axis camera by adjusting the position of the wafer stage with respect to the mask stage by the position adjustment device while imaging the wafer reference mark with the off-axis camera, Forming the alignment mark on the surface of the wafer at the aligned position;
Based on the alignment information of the wafer stage with respect to the mask stage and the positional information of the mark forming apparatus with respect to the off-axis camera, the position of the wafer stage with respect to the mask stage is adjusted by the position adjusting device. Projecting a pattern onto the wafer;
The exposure apparatus according to claim 2, wherein: An exposure method for projecting the pattern onto a wafer having a photosensitive film formed on a surface via a projection optical system by irradiating exposure light onto a mask on which the pattern is formed,
Forming an alignment mark on an outer peripheral portion of the wafer surface supported by a wafer stage where a semiconductor device is not formed;
Aligning the mask stage and the wafer stage by adjusting the position of the wafer stage relative to the mask stage while imaging the mask stage reference mark and the alignment mark of the mask stage by an on-axis camera;
An exposure method comprising:   A method for manufacturing a semiconductor device, comprising an exposure step according to the exposure method according to claim 4.

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