JP2011254027A - Exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure device in which defects such as a foreign material, a flaw, or uneven coating of resist can be detected quickly by observing the entire exposure region every time when light exposure is performed.SOLUTION: The exposure device 1 comprises a DMD element 3, i.e. a pattern generation unit that generates pattern information required for generating a desired exposure pattern, projection optical systems 4 and 40 which project an exposure pattern generated from the DMD element 3 onto a substrate 7, an observation illumination optical system 70 which illuminates the entire projection region with a non-exposure light, an observation optical system 80 which observes the exposure region, and a defect analysis unit 14 which determines whether there is a defect in the exposure region or not based on an observation image from the observation optical system 80.

Description

  The present invention relates to an exposure apparatus.

  Conventionally, an exposure apparatus has been proposed in which an exposure pattern is projected onto a substrate using a spatial light modulation element such as a DMD (Digital Mirror Device), and the projection magnification is variable (for example, Patent Documents). 1).

International Publication No. WO2002 / 039189

  However, in the prior art, even if the exposure substrate has defects such as foreign matter, scratches, and resist coating unevenness, since the exposure is performed without performing the detection process, the above-described defects are noticed after exposure and development. As a result, generation of defective products and waste of work time occurred.

  The present invention has been made in view of such problems, and an exposure apparatus capable of quickly detecting defects such as foreign matter, scratches, and resist coating unevenness by observing the entire exposure region for each exposure. The purpose is to provide.

  In order to solve the above-mentioned problems, an exposure apparatus according to the first aspect of the present invention is an exposure apparatus that projects a desired exposure pattern on a substrate and exposes the substrate, and generates a desired exposure pattern. A generation unit, an exposure illumination optical system for illuminating the pattern generation unit, a projection optical system for projecting the exposure pattern generated by the pattern generation unit onto the substrate, and an exposure area formed on the substrate with non-exposure light An observation illumination optical system, an observation optical system that observes an exposure area illuminated by the observation illumination optical system, and a determination unit that determines the presence or absence of a defect in the exposure area based on an observation result by the observation optical system. It is characterized by having.

  In such an exposure apparatus, it is preferable that the observation illumination optical system has a wavelength selection unit capable of selecting a plurality of wavelengths.

  In such an exposure apparatus, the observation optical system preferably has a filter or a dichroic mirror that cuts exposure light.

  Such an exposure apparatus further includes a pattern generation unit, an exposure light source that constitutes the exposure illumination optical system, and a control unit that controls the operation of the observation light source that constitutes the observation illumination optical system. Before the exposure pattern generated by the pattern generation unit is projected onto the substrate by the exposure illumination optical system and exposed, the exposure area illuminated by the observation illumination optical system is observed by the observation optical system and the presence or absence of a defect is determined by the determination unit. It is preferable to be configured as described above.

  Alternatively, such an exposure apparatus further includes a pattern generation unit, an exposure light source that constitutes the exposure illumination optical system, and a control unit that controls the operation of the observation light source that constitutes the observation illumination optical system. The exposure pattern generated by the pattern generator is projected onto the substrate by the exposure illumination optical system and exposed. At the same time, the exposure area illuminated by the observation illumination optical system is observed by the observation optical system, and the presence or absence of a defect is determined by the determination unit. It is preferable to be configured to do so.

  An exposure apparatus according to a second aspect of the present invention is an exposure apparatus that projects a desired exposure pattern on a substrate and exposes the substrate, and includes a pattern generation unit that generates a desired exposure pattern, and a pattern generation An exposure illumination optical system that illuminates the part, a projection optical system that projects the exposure pattern generated by the pattern generation unit onto the substrate, and an observation optical that observes the exposure area on the substrate on which the exposure pattern is projected by the projection optical system And a determination unit that compares the exposure pattern observed by the observation optical system with the desired exposure pattern generated by the pattern generation unit to determine the presence or absence of a defect in the exposure region. .

  In such an exposure apparatus, the projection optical system is preferably configured so that the projection magnification can be switched, and further includes a magnification control unit that controls switching of the projection magnification of the projection optical system.

  Moreover, it is preferable that such an exposure apparatus further includes a display unit that displays defect information acquired by the determination unit.

  When the exposure apparatus according to the present invention is configured as described above, it is possible to quickly detect defects such as foreign matter, scratches, and resist coating unevenness by observing the entire exposure area for each exposure. It is possible to quickly determine whether to stop, to prevent the generation of defective products, and to improve the exposure work efficiency.

It is the schematic which shows the structure of the exposure apparatus which concerns on 1st, 3rd embodiment. It is the schematic which represented the observation area | region and the exposure area | region which produced the foreign material, the crack, the resist application nonuniformity, etc. with the image. It is a flowchart for demonstrating the specific method of the analysis of the pattern by a defect analysis part. It is the schematic which shows the structure of the exposure apparatus which concerns on 2nd Embodiment.

(First embodiment)
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification, the surface direction on the exposure side of the substrate is referred to as “front side” through the substrate, and the surface direction opposite to the exposure side is referred to as “back side”. First, the configuration of the exposure apparatus 1 according to the first embodiment will be described with reference to FIG. The exposure apparatus 1 is a maskless exposure apparatus that projects and exposes an image from the DMD element 3 onto, for example, a substrate (wafer) 7 coated with a photoresist. As shown in FIG. A control unit 10 that controls illumination, an exposure illumination optical system 2 that irradiates illumination light, and illumination light from the exposure illumination optical system 2 is spatially modulated to produce a plurality of images (hereinafter referred to as “exposure patterns”). DMD element 3 as a pattern generation unit for generating the projection pattern, projection optical system 4 for projecting an exposure pattern from DMD element 3 onto substrate 7, and second projection optics having a different projection magnification from projection optical system 4 The system 40, the magnification controller 11 that controls a switching mechanism (not shown) that switches between the projection optical system 4 and the second projection optical system 40, and information that serves as a basis for generating a desired exposure pattern. Get "pattern information" For the pattern acquisition unit 12 and the exposure area formed on the substrate 7 exposed by the projection optical systems 4 and 40, the light having a desired wavelength that does not sensitize the photoresist coated on the substrate 7 (non-lighting). Observation illumination optical system 70 for illuminating with exposure light), wavelength selection unit 13 for selecting the wavelength of illumination light emitted from the observation illumination optical system 70, and the illumination illuminated by the observation illumination optical system 70 An observation optical system 80 for acquiring and observing an image of the exposure area (hereinafter referred to as “observation image”), and the presence or absence of a defect in the exposure area based on the observation image acquired by the observation optical system 80 A defect analysis unit (determination unit) 14 for determining the presence, a display unit 15 for displaying various information such as an observation image and the presence / absence of a defect, and a stage 9 having a holder 8 for placing the substrate 7 thereon. Configured . The stage 9 is controlled by the control unit 10, and the stage 9 is moved in the vertical direction (the optical axis direction of the projection optical systems 4 and 40) and in the horizontal direction (in the plane orthogonal to the optical axis of the projection optical systems 4 and 40). ) Is provided. Further, the magnification control unit 11, the pattern acquisition unit 12, the wavelength selection unit 13, the defect analysis unit 14, and the like are controlled by the control unit 10. Further, the control unit 10, the magnification control unit 11, the pattern acquisition unit 12, the wavelength selection unit 13, and the defect analysis unit 14 are a computer including a processing unit such as a CPU, a ROM, and a RAM, and a storage unit such as a hard disk. It can be implemented as a program executed by the CPU.

  In addition, the exposure apparatus 1 of the present embodiment is incorporated in the projection optical systems 4 and 40, and an autofocus detection optical system 5 for adjusting the exposure pattern image from the DMD element 3 to focus on the surface of the substrate 7. And a back surface position detection optical system 6 for detecting an alignment mark formed on the back surface side of the substrate 7. In addition, a storage unit (not shown) that stores various data and programs is also provided. The operations of these units are also controlled by the control unit 10.

  The DMD element 3 includes a plurality of micromirrors (not shown) that can change the reflection angle. Each micromirror of the DMD element 3 is driven by the control unit 10 to arbitrarily select whether or not to guide the reflected light to the projection optical systems 4 and 40 by changing the reflection angle of the reflection surface. It is possible to generate exposure patterns of various shapes.

  The exposure illumination optical system 2 condenses the illumination light from the exposure light source 21 that emits a wavelength for exposing the photoresist coated on the substrate 7 made of a mercury lamp, LED, etc., and condenses the illumination light from the exposure light source 21 to the DMD element 3. It is comprised from the condenser lens 22 to irradiate. The projection optical system 4 also includes a second objective lens 41 that converts the exposure pattern light (exposure light) generated by the DMD element 3 into substantially parallel light, and a first that projects the substantially parallel light onto the substrate 7. And an objective lens 42. Here, the meaning of substantially parallel means that light emitted from one point on the DMD element 3 becomes substantially parallel, and light emitted from another point on the DMD element 3 also becomes substantially parallel. However, the angle of light of both is different.

  Further, like the projection optical system 4, the second projection optical system 40 includes a second objective lens 43 and a first objective lens 44. The projection magnification between the DMD element 3 and the substrate 7 can be changed by switching the projection optical system 4 to the second projection optical system 40 under the control of the magnification control unit 11.

  In the following description, the case of using the exposure apparatus 1 configured to perform exposure using the two projection optical systems 4 and 40 having different magnifications will be described. However, three or more different magnifications or the magnification may be changed continuously. It can also be used in an exposure apparatus that can Hereinafter, the projection optical systems 4 and 40 having a plurality of magnifications may be collectively referred to as “projection optical system 4”. Furthermore, the plurality of first objective lenses 42 and 44 may be collectively referred to as a “first objective lens 42”, and the plurality of second objective lenses 41 and 43 may be collectively referred to as a “second objective lens 41”.

  The observation illumination optical system 70 includes an observation light source 71 (including a white light source, an LED, a halogen lamp, a fiber light source, or the like) that emits observation illumination light, and observation illumination light from the observation light source 71. Are arranged on the optical path of the projection optical system 4 and the illumination light for observation is arranged on the substrate 7, the aperture stop 73, the field stop 74, the first relay lens 75 and the second relay lens 76. A half mirror 77 reflecting in the direction is shared, and the first objective lens 42 or 44 of the projection optical system 4 or 40 is shared. The observation illumination optical system 70 illuminates the substrate 7 with observation illumination light having a wavelength that does not expose the photoresist on the substrate 7. Therefore, in this embodiment, although the details will be described later, a filter 78 for cutting the exposure wavelength band is disposed between the observation light source 71 and the condenser lens 72. Further, the observation illumination light emitted from the observation light source 71 during illumination is configured to be freely selected by the wavelength selection unit 13, and is switched to observation illumination light having a different wavelength to observe defects on the substrate 7. be able to.

  The observation optical system 80 is disposed on the optical path of the observation illumination optical system 70, reflects the observation light reflected from the substrate 7 by irradiation of the observation illumination light, and the first mirror reflected by the half mirror 83. An imaging lens 82 that forms an image of the observation light condensed by the objective lenses 42 and 44 and a two-dimensional imaging device 81 that detects this image are formed. The first objective lens 42 or 44 and the imaging lens 82 Are configured to conjugate the surface of the substrate 7 and the two-dimensional imaging device 81 in a conjugate manner to observe the surface of the substrate 7. In the two-dimensional image sensor 81, the surface image of the substrate 7 is photoelectrically converted, and an image of the exposure region (hereinafter referred to as “observation image”) is observed by substrate image processing. As shown in FIG. 2, the range that can be observed with the observation optical system 80, that is, the observation region 100 shown in FIG. 2 has a range that can include the exposure region 110.

  In the defect analysis unit 14, based on the observation image detected by the observation optical system 80, it is determined whether foreign matter is mixed in the photoresist on the substrate 7 or the photoresist on the substrate 7, or whether there are scratches or uneven coating, for example, an image Analyze by processing. If there is a defect as a result of this analysis, in the present embodiment, the observation image and the fact that there is a defect are displayed on the display unit 15, and the control unit 10 and the operator are notified that there is a defect. Moreover, you may make it emit a warning sound. A specific analysis method in the defect analysis unit 14 will be described later.

  The autofocus detection optical system 5 emits a point light source 51 that emits focus detection light having a wavelength that does not expose the photoresist coated on the substrate 7 (hereinafter, referred to as “focus detection light”), and the point light source 51. A collimator lens 52 for converting the focus detection light from the light into a substantially parallel light, a light-shielding stop 53 that blocks half of the pupil of the focus detection light transmitted through the collimator lens 52, and the substantially parallel focus detection light transmitted. The half mirror 54 that further reflects the reflected light reflected by the substrate 7 and the dichroic mirror 55 that is disposed on the optical path of the projection optical system 4 and reflects the focus detection light and the reflected light and transmits the exposure light. An imaging lens 56 that forms an image of the reflected light reflected by the dichroic mirror 55 and the half mirror 54, and a linear sensor that receives this image. And a support 57.

  Here, the operation of the autofocus detection optical system 5 will be described. First, focus detection light emitted from the point light source 51 is converted into substantially parallel light by the collimator lens 52. As described above, the substantially parallel focus detection light is narrowed down by blocking about half of the pupil by the light-shielding diaphragm 53, then passes through the half mirror 54, and enters the dichroic mirror 55. The dichroic mirror 55 Thus, the light is reflected in the direction of the substrate 7 and irradiated onto the substrate 7 through the first objective lens 42 of the projection optical system 4. Then, the reflected light reflected by the substrate 7 is condensed again by the first objective lens 42 of the projection optical system 4, then reflected by the dichroic mirror 55 and guided to the autofocus detection optical system 5. The reflected light is further reflected by the half mirror 54 and imaged on the linear sensor 57 by the imaging lens 56. Thus, the autofocus detection optical system 5 is a so-called pupil half-hidden focus detection optical system. Then, based on the image obtained by the linear sensor 57, the vertical displacement of the substrate 7 with respect to the in-focus position of the projection optical system 4 is detected, and the control unit 10 passes the stage drive unit 16 based on the signal. The stage 9 is moved in the optical axis direction (vertical direction) to focus the exposure pattern from the DMD element 3 on the surface of the substrate 7.

  The back surface position detection optical system 6 is disposed on the side facing the projection optical system 4 with the holder 8 interposed therebetween, that is, below the holder 8. The back surface position detection optical system 6 includes a position detection light source 61 that emits position detection light (hereinafter referred to as “position detection light”), and a condenser that collects the position detection light from the position detection light source 61. The lens 62, the half mirror 63 that reflects the position detection light collected by the condenser lens 62 toward the substrate 7, and the position detection light reflected by the half mirror 63 is condensed to illuminate the back surface of the substrate 7. An objective lens 64, an imaging lens 65 that forms an image of reflected light that is reflected from the back surface of the substrate 7, reflected by the objective lens 64, and transmitted through the half mirror 63, and an image sensor 66 that detects this image. It is configured.

  In the present embodiment and the following embodiments, the back surface position detection optical system 6 as described above is used as the alignment means of the substrate 7, but the present application is not limited to this, and from the front surface side. Alignment may be performed, and any conventionally known means other than these may be used.

  The holder 8 on which the substrate 7 is placed has a through-hole 8a penetrating in the vertical direction (the optical axis direction of the projection optical system 4 and the back surface position detection optical system 6; hereinafter, this vertical direction is referred to as “Z-axis”). Is formed. This through hole 8 a is an opening for observing the alignment mark formed on the back surface of the substrate 7. For example, three or more alignment marks such as cross marks are formed on the back surface of the substrate 7, and these alignment marks are passed through a plurality of through holes 8 a formed corresponding to each alignment mark. Then, the back surface position detection optical system 6 detects. At this time, the stage 9 is moved in the horizontal direction and the vertical direction (vertical direction) by the stage driving unit 16 controlled by the control unit 10 in order to detect the alignment mark by the back surface position detection optical system 6. Note that a position measuring unit 17 including an interferometer or a linear encoder is attached to the stage 9, and the position (coordinates) of the holder 8 is monitored by the control unit 10.

  When performing exposure of the substrate 7 using the exposure apparatus 1 having the above-described configuration, first, the substrate 7 is aligned by the alignment mark formed on the back surface of the substrate 7 by the back surface position detection optical system 6. Do. In the back surface position detection optical system 6, the position detection light emitted from the position detection light source 61 is incident on the half mirror 63 via the condenser lens 62, reflected by the half mirror 63, and then collected by the objective lens 64. The back surface of the substrate 7 is illuminated through the through hole 8 a provided in the holder 8. As described above, three or more alignment marks are formed on the back surface of the substrate 7. The position detection light reflected by the back surface of the substrate 7 is condensed again by the objective lens 64 to become substantially parallel light, passes through the half mirror 63, and then forms an image on the image sensor 66 by the imaging lens 65. In this image sensor 66, the back image of the substrate 7 is photoelectrically converted, and the alignment mark is recognized by image processing.

  The stage 9 is moved under the control of the control unit 10 so that the centers of the three or more alignment marks recognized by the image sensor 66 are sequentially matched. And the control part 10 calculates the position in the horizontal surface on the coordinate in the stage 9 of the board | substrate 7, and the rotation amount in a horizontal surface by reading the coordinate of the stage 9 in that case. Based on the position and rotation amount of the substrate 7 calculated in this way, the stage 9 is moved to move the substrate 7 to a predetermined exposure position, thereby positioning the exposure.

  Then, the exposure area 110 is observed by the observation illumination optical system 70 and the observation optical system 80, and the defect analysis unit 14 determines the presence or absence of a defect. For this purpose, first, the wavelength selecting unit 13 selects non-exposure light and observation illumination light having a desired wavelength. In the observation illumination optical system 70, observation illumination light having a wavelength corresponding to the selection by the wavelength selection unit 13 is emitted from the observation light source 71. The observation illumination light is condensed by the condenser lens 72, passes through the aperture stop 73 and the field stop 74, relayed by the first relay lens 75 and the second relay lens 76, and directed toward the substrate 7 by the half mirror 77. Reflected. The reflected observation illumination light is irradiated onto the substrate 7 by the first objective lens 42 of the projection optical system 4. The observation light reflected from the substrate 7 is converted into substantially parallel light by the first objective lens 42, reflected by the half mirror 83 of the observation optical system 80 in the direction of the imaging lens 82, and then by the imaging lens 82. An image is formed and an observation image is detected by the two-dimensional image sensor 81. Since the projection optical system 4 and the observation optical system 80 share the first objective lens 42, even if the magnification is changed by switching the first objective lens 42 or zooming, the exposure area 110 and the observation area 100 are changed. The relative size is kept constant.

  Based on the observation image thus detected, the defect analysis unit 14 determines the presence or absence of a defect. As shown in FIG. 2, when a defect such as foreign matter a, scratch b, or resist coating unevenness c is found in the exposure area 110, the defect analysis unit 14 provides information on the presence of the defect and its degree. Be notified. With this notification, the control unit 10 displays an observation image or a defect on the display unit 15 and waits for an instruction from the operator. At this time, a warning sound or the like may be emitted to alert the operator. Then, according to an instruction from the operator, the control unit 10 determines whether to continue or stop the exposure, or to skip this exposure and move to the next exposure position by moving the stage 9. Follow the action.

  In each of the above embodiments, the control unit 10 determines whether to continue or stop the exposure, or to skip the exposure and move to the next exposure position according to an instruction from the operator, Although it is configured to perform subsequent operations, the present application is not limited to this, and as another different embodiment, a predetermined waiting time is determined in advance, and even if this waiting time has passed, the operator's If not instructed, the exposure may be continued. Further, without waiting for the operator's instruction, the control unit 10 may automatically determine whether or not to continue the exposure according to the degree of the defect, and may perform the next operation.

  As described above, since the wavelength of the observation illumination light emitted from the observation light source 71 can be freely selected by the wavelength selection unit 13, the observation image is displayed multiple times by switching the wavelength of the observation illumination light. It is preferable to obtain. In other words, since defects such as foreign matter, scratches, and resist coating unevenness look different depending on the wavelength, the defects can be efficiently observed by sequentially observing with observation illumination lights having different wavelengths as in this embodiment. Can be found, and the accuracy of defect detection can be improved. In particular, when the resist coating unevenness is observed with monochromatic light, defects are easily detected due to the thin film interference effect. In addition, since the wavelength which is easy to observe changes with film thicknesses, it is preferable to select an appropriate wavelength corresponding to the film thickness.

  Further, as described above, it is preferable to appropriately select and arrange the filter 78 in the observation illumination optical system 70 for the observation optical system 80. As an example of the filter 78, for example, when a white light source is used as the observation light source 71, a filter 78 that cuts an exposure wavelength band from the white light source can be used. Alternatively, a plurality of wavelength selection filters 78 for extracting a specific wavelength other than the exposure wavelength band from the white light source may be prepared and replaced according to a necessary wavelength. In this embodiment, as shown in FIG. 1, the filter 78 is disposed between the observation light source 71 and the condenser lens 72. However, the present application is not limited to this, and the observation illumination optical system is not limited thereto. It may be placed elsewhere in the system 70. Further, it may be arranged not on the observation illumination optical system 70 but on the light receiving side of the observation optical system 80. The exposure wavelength incident on the observation side is cut to observe the observation image with higher accuracy. it can. When the filter 78 is arranged on the observation optical system 80 side, it is preferable to always arrange a filter for cutting the exposure wavelength band in the observation illumination optical system 70 in order not to expose the resist.

  Now, an example of a specific method of defect analysis in the defect analysis unit 14 will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 3, an observation image detected by the two-dimensional image sensor 81 of the observation optical system 80 is acquired via the control unit 10 (step S100). Next, the acquired observation image is processed with a differential filter and converted into a differential image (step S110). As the differential filter, a gradient (primary differentiation) filter or a Laplacian (secondary differentiation) filter can be used. Next, based on this differential image, it is determined whether there is a pixel that exceeds a predetermined threshold (step S120). When it is determined that there is a pixel that exceeds the threshold (that is, when it is determined that the luminance change between adjacent pixels or pixels in a predetermined area is large), foreign matter a, scratch b, resist coating unevenness If a defect such as c is detected, information indicating the presence of the defect and its degree are reported to the control unit 10 (step S130), and the process is terminated. On the other hand, when the values of all the pixels are smaller than the threshold value (that is, when the luminance change is small), it is determined that there is no defect, and the process ends. In addition, the above process is performed, for example, every time the observation illumination is changed in wavelength as described above.

  As described above, when a defect is not detected by the defect analysis unit 14 or when exposure is continued according to an instruction from an operator or the control unit 10 even if a defect is detected, the pattern acquisition unit 12 first has the substrate 7. Pattern information (image data) for generating an exposure pattern to be projected onto the photoresist applied thereon is acquired. This pattern information is, for example, information obtained by digitally converting an electronic circuit pattern. Information input by a keyboard, read by a scanner, or created by CAD is stored in a storage unit or memory (not shown). Has been. The pattern acquisition unit 12 reads pattern information from these input devices and storage devices and passes the pattern information to the control unit 10. In this case, in the exposure apparatus 1, illumination light (exposure light) emitted from the exposure light source 21 of the exposure illumination optical system 2 is applied to the DMD element 3 through the condenser lens 22. At this time, the control unit 10 controls the reflection angles of all the micromirrors corresponding to the pixels of the DMD element 3 in response to a signal of a pattern generator (not shown) built in the control unit 10. With this control, each micromirror of the DMD element 3 can select whether or not to guide the illumination light to the projection optical system 4, and a desired exposure pattern can be generated. The exposure pattern generated by the DMD element 3 is projected onto the substrate 7 by the projection optical system 4. At this time, based on the focus signal from the autofocus detection optical system 5 incorporated in the projection optical system 4, the stage 9 is moved up and down via the stage drive unit 13 under the control of the control unit 10, The exposure pattern is projected so as to be focused on the surface of the substrate 7. Then, exposure of the substrate 7 is performed by projection of the exposure pattern.

  As described above, in the exposure apparatus 1 of the present embodiment, it is possible to quickly detect defects such as foreign matter a, scratches b, and resist coating unevenness c by observing the entire exposure region 100 before performing exposure. Thus, it is possible to quickly determine whether to continue or stop the exposure. Therefore, it is possible to perform an efficient exposure operation such as preventing generation of defective products and preventing waste of work.

(Second Embodiment)
Next, an exposure apparatus according to the second embodiment will be described with reference to FIG. As shown in FIG. 4, the exposure apparatus 1 ′ of the second embodiment has basically the same configuration as that of the first embodiment, but does not have an observation illumination optical system 70. Observation is performed by the observation optical system 80 using the exposure light of the projection optical system 4. That is, in the first embodiment, defect detection is performed before exposure, but in the second embodiment, defect detection is performed simultaneously with exposure.

  Therefore, when the substrate 7 is aligned by the back surface position detection optical system 6 before exposure, the projection optical system 4 projects the exposure pattern generated by the DMD element 3 onto the substrate 7 for exposure. At this time, after the observation light reflected from the photoresist on the substrate 7 is converted into substantially parallel light by the first objective lens 42 and reflected by the half mirror 83 of the observation optical system 80 toward the imaging lens 82, An image is formed by the imaging lens 82, and an observation image is detected by the two-dimensional image sensor 81. In the defect analysis unit 14, the pattern acquired by the pattern acquisition unit 12 and the observation image detected by the two-dimensional image sensor 81 of the observation optical system 80 are compared and evaluated by, for example, processing such as pattern recognition. It is detected whether the photoresist is free from defects such as foreign matter, scratches, and film thickness unevenness. In this case as well, as in the first embodiment, it may be determined for each pixel by a differential value.

  In the case of the exposure apparatus according to the second embodiment, the presence or absence of a defect cannot be determined before exposure, but information such as the exposure position where the defect has occurred is stored in a storage unit or the like. By displaying on the display unit 15 or the like, the operator can be notified of which substrate 7 has a defect. Therefore, the operator can quickly respond to the defect, and work efficiency can be improved. Further, since the observation illumination optical system 70 is not used, it is possible to reduce the cost and simplify the apparatus.

(Third embodiment)
Next, an exposure apparatus according to the third embodiment will be described. The exposure apparatus of the third embodiment has basically the same configuration as that of the first embodiment, and performs observation with the observation optical system 80 using exposure light. Further, in the third embodiment, in addition to the configuration of the first embodiment, a filter 84 that cuts the exposure wavelength band is disposed in the observation optical system 80 of FIG. That is, by irradiating the observation illumination light onto the surface of the substrate 7 simultaneously with the exposure, the observation image of the surface of the substrate 7 is obtained by the two-dimensional imaging device 81 of the observation optical system 80 as in the first embodiment. Can be obtained. Then, in the defect analysis unit 14, the observation image detected by the two-dimensional imaging device 81 through the filter 84 is treated with the same method as that in the first embodiment described above. Detects whether there are defects such as unevenness. In FIG. 1, the filter 84 is disposed between the imaging lens 82 and the two-dimensional image sensor 81, but the present application is not limited to this, and other locations in the observation optical system 80. You may arrange in. The filter 84 is not limited, and a dichroic mirror or the like may be used as long as the exposure wavelength can be cut.

  Thus, by cutting the exposure wavelength band with the filter 84, the exposure pattern can be removed when the observation image is detected by the two-dimensional imaging device 81. Since the exposure pattern can be removed in this way, it is easier to determine the defect than in the second embodiment. In addition, since the exposure area is observed simultaneously during exposure, the processing time can be shortened and the exposure work efficiency can be improved.

  Further, in each of the above embodiments, the projection optical system 4 including the first objective lens 42 and the second objective lens 41 is used as the magnification switching mechanism, and the first objective lens 44 and the second objective lens 43 are used as the magnification switching mechanism. However, the present invention is not limited to this, and it is not always necessary to switch the projection optical systems 4 and 40 as a whole. For example, only the first objective lens 42 may be switched to an objective lens having a different focal length (for example, the first objective lens 44), or only the second objective lens 41 may have an objective lens having a different focal length (for example, a second objective lens). It is good also as a structure switched to the objective lens 43). The projection optical systems 4 and 40 may be zoom lenses. However, from the viewpoint of ease of aberration correction, a method of switching the entire projection optical systems 4 and 40 as in the present embodiment is preferable.

DESCRIPTION OF SYMBOLS 1,1 'Exposure apparatus 2 Exposure illumination optical system 3 DMD element (pattern production | generation part) 4,40 Projection optical system 7 Substrate 10 Control part 11 Magnification control part 13 Wavelength selection part 14 Defect analysis part (determination part) 15 Display part 70 Observation illumination optical system 80 Observation optical system 84 Filter

Claims (8)

An exposure apparatus that projects a desired exposure pattern on a substrate to expose the substrate,
A pattern generator for generating the desired exposure pattern;
An exposure illumination optical system for illuminating the pattern generation unit;
A projection optical system that projects the exposure pattern generated by the pattern generation unit onto the substrate;
An observation illumination optical system for illuminating an exposure region formed on the substrate with non-exposure light;
An observation optical system for observing the exposure area illuminated by the observation illumination optical system;
An exposure apparatus comprising: a determination unit that determines presence / absence of a defect in the exposure region based on an observation result by the observation optical system.   The exposure apparatus according to claim 1, wherein the observation illumination optical system includes a wavelength selection unit capable of selecting a plurality of wavelengths.   The exposure apparatus according to claim 1, wherein the observation optical system includes a filter or a dichroic mirror that cuts exposure light. The pattern generation unit, an exposure light source constituting the exposure illumination optical system, and a control unit for controlling the operation of the observation light source constituting the observation illumination optical system;
The control unit projects the exposure area illuminated by the observation illumination optical system by the observation optical system before the exposure pattern generated by the pattern generation unit is projected onto the substrate by the exposure illumination optical system and exposed. The exposure apparatus according to claim 1, wherein the exposure apparatus is configured to observe and determine the presence or absence of the defect by the determination unit. The pattern generation unit, an exposure light source constituting the exposure illumination optical system, and a control unit for controlling the operation of the observation light source constituting the observation illumination optical system;
The control unit projects and exposes the exposure pattern generated by the pattern generation unit onto the substrate by the exposure illumination optical system, and simultaneously observes the exposure region illuminated by the observation illumination optical system by the observation optical system. The exposure apparatus according to claim 1, wherein the determination unit is configured to determine the presence or absence of the defect. An exposure apparatus that projects a desired exposure pattern on a substrate to expose the substrate,
A pattern generator for generating the desired exposure pattern;
An exposure illumination optical system for illuminating the pattern generation unit;
A projection optical system that projects the exposure pattern on the substrate generated by the pattern generation unit onto the substrate;
An observation optical system for observing an exposure region on which the exposure pattern is projected by the projection system;
A determination unit that compares the exposure pattern observed by the observation optical system with the desired exposure pattern generated by the pattern generation unit to determine the presence or absence of a defect in the exposure region;
An exposure apparatus comprising: The projection optical system is configured so that the projection magnification can be switched,
The exposure apparatus according to claim 1, further comprising the magnification control unit that controls switching of a projection magnification of the projection optical system.   The exposure apparatus according to claim 1, further comprising a display unit that displays defect information acquired by the determination unit.

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