JP4002429B2 - Exposure apparatus having foreign substance inspection function and foreign substance inspection method in the apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure apparatus such as a proximity exposure apparatus or a contact exposure apparatus that forms a minute gap between a mask for pattern formation and an exposure target substrate and transfers the pattern onto the substrate surface of the exposure target substrate. In particular, the present invention relates to an exposure apparatus having a foreign matter inspection function capable of inspecting the presence or absence of foreign matter on a pattern surface of a mask or an exposure surface of an exposure target substrate, and a foreign matter inspection method in the apparatus.
[0002]
[Prior art]
The proximity exposure apparatus is applied to an exposure process for forming a pattern on a substrate surface of an exposure target substrate such as a glass substrate or a color filter in a manufacturing process of a flat panel display such as a liquid crystal display or a plasma display. In recent years, the size of glass substrates has been increased with the increase in size of liquid crystal displays, and the size of photomasks has also been increasing accordingly. In the proximity exposure apparatus, when the size of the photomask and the glass substrate is substantially the same, a batch exposure method is used in which the pattern is exposed on the glass substrate surface in a lump, and the glass substrate is larger than the size of the photomask. When the size is large, for example, a step exposure method is adopted in which the glass substrate is stepped in the horizontal direction with respect to the photomask, and the pattern is divided and exposed on the glass substrate surface.
[0003]
In the above-described proximity exposure apparatus, when forming a pattern on the substrate surface of the glass substrate, positioning control of the glass substrate so that the distance between the photomask and the glass substrate becomes a small gap (separation gap), so-called proximity gap control. It is carried out. As an example, the gap between the photomask held by the mask holder and the glass substrate held by the exposure chuck is detected by a plurality of gap detection sensors, and the exposure chuck is set to Z by the tilting stage so that the detection values of each sensor are all equal. Tilt in the direction to form a certain small gap between the photomask and the glass substrate. This minute gap is formed between the pattern surface of the photomask (the surface on which the mask pattern is formed) and the exposure surface of the glass substrate (the surface on which the photoresist film is formed). For example, the size of the photomask or the glass substrate The gap value is set to about several tens to several hundreds of microns according to the above. In addition, alignment is performed so that the photomask and the glass substrate are aligned with high accuracy while a minute gap is secured. As an example, an alignment mark provided opposite to the photomask and the glass substrate is detected by an image sensor such as a CCD, and the amount of deviation between the photomask and the glass substrate is obtained from the detection result, and the amount of correction of the amount of deviation is corrected. Only by moving the exposure chuck in the X direction or Y direction on the alignment stage, the photomask and the glass substrate are aligned.
[0004]
[Problems to be solved by the invention]
In the proximity exposure apparatus, for example, if there is a relatively large foreign object on the exposure surface of the glass substrate, the foreign object may come into contact with the pattern surface during the proximity gap control. That is, in the glass substrate, in the photosensitive solution coating step before the exposure step, an exposure surface is formed by coating a photoresist with a certain thickness on the surface to be exposed. When the photoresist is applied, the photoresist is applied. May be scattered and scattered on the exposure surface. Further, in the photomask, as the size of the photomask increases, there is a tendency that the gap between the central portion and the exposure surface is reduced due to its own weight due to its own weight. In this case, if there is a scattered resist in a portion where the gap interval is narrow on the exposure surface, there arises a problem that the scattered resist comes into contact with the pattern surface and damages the pattern. Also, in alignment, the glass substrate is moved relative to the photomask while ensuring a small gap, so that there is a problem that the resist film and the pattern are rubbed and scratched by the scattered resist as the glass substrate moves. Occur. Further, when the glass substrate descends together with the exposure chuck, the scattered resist may adhere to the pattern surface away from the exposure surface.
[0005]
Usually, in the batch exposure method, since the same pattern is formed on a plurality of glass substrates using a single photomask, the glass on which the pattern is exposed due to damage to the pattern or adhesion of scattered resist to the pattern surface. Since the repeated baking failure of the pattern occurs on all the substrates, the yield decreases. Such a problem occurs not only in the batch exposure method but also in the step exposure method. In particular, in the step exposure method, the same pattern may be exposed on a plurality of glass substrates using one photomask, so that the yield is further reduced as compared with the batch exposure method.
[0006]
One way to avoid this problem is to observe the transfer pattern transferred to the exposed surface of the glass substrate using a review station or a scanning electron microscope, and if the transfer pattern is damaged, It is conceivable to replace the corresponding photomask with a new one. However, this method has a problem that it takes time to observe the transfer pattern, and it is necessary to prepare a plurality of replacement photoresists, which increases the running cost.
[0007]
The present invention relates to an exposure apparatus having a foreign matter inspection function capable of inspecting the pattern surface and exposure surface for the presence of foreign matter before bringing the pattern surface of the mask close to the exposure surface of the exposure target substrate, and foreign matter in the device. It is intended to provide an inspection method.
[0008]
[Means for Solving the Problems]
An exposure apparatus according to the present invention is an exposure apparatus that performs exposure by bringing a pattern surface of a mask held by a mask holder and an exposure surface of an exposure target substrate held by an exposure chuck close to each other. prior to approximate the exposure surface of the target substrate, a driving means for driving at least one of the mask holders and the exposure chuck for relative movement between the exposure target substrate and the mask, said by the drive means while driving the mask holder at least one of the exposure chuck relative movement between the exposure target substrate and the mask, respectively simultaneously optically detecting the state of the exposure surface and the state of the pattern surface And detecting the presence or absence of foreign matter on the pattern surface based on the output of the detection unit corresponding to the pattern surface and responding to the exposure surface. And is obtained and control means for performing processing for determining foreign object presence or absence of the exposure plane based on an output of said detecting means.
The foreign matter inspection method according to the present invention provides an exposure apparatus that performs exposure by bringing a pattern surface of a mask held by a mask holder and an exposure surface of an exposure target substrate held by an exposure chuck close to each other. A foreign matter inspection method for inspecting the presence or absence of foreign matter on an exposure surface, wherein the mask and the exposure target substrate are relatively moved before the pattern surface of the mask and the exposure surface of the exposure target substrate are brought close to each other. relatively moving a step of driving at least one of the mask holders and the exposure chuck, and the mask by driving at least one of the exposure chuck and the mask holder by the step and the exposure target substrate as during that, the step of detecting the status of said exposure surface of said patterned surface simultaneously optically respectively, detected in accordance with the pattern surface Together determine the foreign matter whether the pattern surface on the basis of the over data comprises a step of determining a foreign object presence or absence of the exposure surface based on the detection data corresponding to the exposure surface.
According to the exposure apparatus and particle inspection method, in a state before approximating the pattern surface and the exposure surface of the exposure target substrate mask, because at the same time to detect the foreign object presence on the pattern surface and the exposure surface, the pattern surface and Inspection of the presence or absence of foreign matter can be efficiently performed on the exposed surface. In addition, by performing this detection in a state before the pattern surface of the mask and the exposure surface of the exposure target substrate are brought close to each other, the detection is performed in a state where the distance between both surfaces is sufficiently open. It is possible to detect simultaneously without damaging. Furthermore, while performing two types of detection, that is, a pattern surface and an exposure surface, an increase in tact time due to the detection process does not occur. In addition, after the exposure of one substrate is completed, before the exposure to another substrate is started, the inspection of the pattern surface of the mask according to the present invention and the exposure surface of the substrate to be exposed is performed at the same time. Even when foreign matter or the like adheres to the pattern surface of the mask, this can be reliably and efficiently detected.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an exposure apparatus according to the present invention will be described with reference to the accompanying drawings.
In the present embodiment, as an exposure apparatus, for example, a proximity exposure apparatus applied to an exposure process for forming a pattern on a substrate surface of a glass substrate in a manufacturing process of a flat panel display such as a liquid crystal display or a plasma display will be described. To do. FIG. 1 shows a schematic configuration of the proximity exposure apparatus.
[0010]
In FIG. 1, a proximity exposure apparatus includes a mask holder 1, an exposure chuck 2, a tilting stage 3, an alignment stage 4, a stage guide 5, a foreign substance detection system 6 for a glass substrate, and a photomask. A foreign matter detection system 7, a stage driving device D for moving an exposure chuck, an exposure unit (not shown) for irradiating exposure light, and the like are provided. An alignment stage 4 is movably mounted on the stage guide 5. An exposure chuck 2 is attached to the alignment stage 4 via a tilting stage 3. The stage driving device D is for moving the exposure chuck 2 along the stage guide 5 in the X-axis direction indicated by XYZ coordinates in the drawing. As the stage driving device D, for example, an appropriate driving device such as a linear motor can be used. In this case, the driving device is disposed in the stage guide 5, and the exposure chuck 2 is moved along the stage guide 5 in the X-axis direction via the alignment stage 4 with the driving device. The tilting stage 3 includes, for example, three tilting drive motors that tilt the exposure chuck 2 in the Z-axis direction indicated by the XYZ coordinates. The alignment stage 4 includes, for example, an X-axis table 4a and a Y-axis table 4b that move the exposure chuck 2 independently in the X-axis direction and the Y-axis direction indicated by the same XYZ coordinates.
[0011]
The mask holder 1 is fixed above the stage guide 5 to a mask base 8 provided on the glass substrate delivery position side described later. The mask holder 1 is formed in a frame shape having a lower opening window 1a for exposure light incidence in the center, and the upper surface peripheral portion of the photomask M conveyed by an automask changer (not shown) at the lower peripheral portion. Adsorb and hold. The lower surface of the photomask M is a pattern surface Ma on which a mask pattern is formed.
[0012]
The exposure chuck 2 holds the glass substrate P at the glass substrate delivery position indicated by a solid line in the drawing. That is, the lower surface of the glass substrate P transported by a transport arm (not shown) is sucked and held at the glass substrate delivery position. The upper surface of the glass substrate P is an exposure surface Pa made of a photoresist film. At the glass substrate delivery position, the glass substrate P is in a position not facing the photomask M. The exposure chuck 2 holding the glass substrate P has a stage driving device D before the proximity gap control for forming a minute gap between the exposure surface Pa of the glass substrate P and the mask surface Ma of the photomask M is performed. By moving the alignment stage 4 in the X-axis direction indicated by the arrow in the figure, the alignment stage 4 is moved from the glass substrate delivery position to the exposure start position indicated by the alternate long and short dash line in the figure. The glass substrate P faces the photomask M at the exposure start position.
[0013]
The foreign matter detection system 6 for the glass substrate includes a light irradiation system 6a, a fiber condensing system 6b, a detector 6c such as a photomultiplier (see FIG. 4), and the like. The light irradiation system 6a and the fiber condensing system 6b are attached to the outer surface of the mask base 8 on the glass substrate delivery position side. As shown in FIG. 2, the light irradiation system 6a includes a projector 6a1, a light receiver 6a2, and the like. The light projector 6a1 and the light receiver 6a2 are respectively disposed on the glass substrate P so as to face the outside of one end and the other end in the direction intersecting the moving direction of the exposure chuck 2 (that is, the Y-axis direction shown in FIG. 1). . While the exposure chuck 2 moves from the glass substrate delivery position to the exposure start position, the projector 6a1 emits the irradiation light L1 that irradiates the exposure surface Pa of the glass substrate P toward the light receiver 6a2. In this case, since the glass substrate P moves with respect to the irradiation light L1, the entire exposure surface Pa is irradiated with the irradiation light L1 as the glass substrate P moves. When the exposure surface Pa is irradiated with the irradiation light L1, scattered light AL1 is generated from foreign matter (for example, scattering resist on the exposure surface Pa) A existing on the exposure surface Pa. Specifically, if there is a foreign matter A on the smooth surface of the exposure surface Pa, the irradiation light L1 is irregularly reflected and scattered by the unevenness of the foreign matter A on the smooth surface. The scattered light AL1 diffusely reflected by the foreign matter A is output to the detector 6c through the fiber condensing system 6b. Note that when the irradiation light L1 is collimated light having an elliptical cross-sectional shape, the set position of the projector 6a1 can be easily set. This is because in the collimated light, the projector 6a1 can be set so as to irradiate the exposure surface Pa on the long diameter side or the short diameter side.
[0014]
The foreign matter detection system 7 for the photomask includes a light irradiation system 7a, a fiber condensing system 7b, a detector 7c such as a photomultiplier (see FIG. 4), and the like. The light irradiation system 7 a and the fiber condensing system 7 b are attached to the outer surface of the alignment stage 4 on the photomask M side via the stage base 9. As shown in FIG. 3, the light irradiation system 7a includes a projector 7a1, a light receiver 7a2, and the like. The light projector 7a1 and the light receiver 7a2 are respectively disposed on the photomask M so as to be opposed to the outside of one end and the other end in a direction intersecting the moving direction of the exposure chuck 2 (ie, the Y-axis direction shown in FIG. 1). . The light projector 7a1 emits irradiation light L2 for irradiating the pattern surface Ma of the photomask M toward the light receiver 7a2 while the exposure chuck 2 moves from the glass substrate delivery position to the exposure start position. In this case, since the photomask M moves with respect to the irradiation light L2, the entire pattern surface Ma is irradiated with the irradiation light L2 as the photomask M moves. When the pattern surface Ma is irradiated with the irradiation light L2, scattered light BL2 is generated from a foreign substance B (for example, a scattered resist attached to the pattern surface Ma away from the exposure surface Pa) B existing on the pattern surface Ma. Specifically, when the foreign matter B is present on the smooth surface of the pattern surface Ma, the irradiation light L2 is irregularly reflected and scattered by the unevenness of the foreign matter B on the smooth surface. The scattered light BL2 diffusely reflected by the foreign matter B is output to the detector 7c via the fiber condensing system 7b. Also in this case, if the irradiation light L2 is collimated light having an elliptical cross section, the set position of the projector 7a1 can be easily set. This is because in the collimated light, the projector 7a1 can be set so as to irradiate the pattern surface Ma on the long diameter side or the short diameter side.
[0015]
In FIG. 4, each detector 6c, 7c receives scattered light AL1, BL2 from the fiber condensing systems 6b, 7b, and detects signals (luminance levels) corresponding to the received light levels (luminance levels) of the scattered lights AL1, BL2. For example, current values SA and SB corresponding to the luminance level are output to the control unit 10 . The control unit 10 includes a microcomputer including an interface 10a, an MPU 10b, a memory 10c including a ROM and a RAM, and the like. The memory 10c stores various programs necessary for driving the device, reference data (setting data) for foreign matter determination, and the like. The MPU 10b executes a predetermined program stored in the memory 10c to determine the presence or absence of a foreign object. Although not shown in FIG. 4, the tilting stage 3, the alignment stage 4, the stage driving device D, and the like are driven and controlled.
[0016]
FIG. 5 shows an example of a foreign matter presence / absence determination process performed by the control unit 10.
In FIG. 5, in step S1, detection signals SA and SB obtained from the detectors 6c and 7c are fetched, the detection signals SA and SB are appropriately processed, and detection data DA and SB corresponding to the detection signals SA and SB are obtained. Find the DB.
In step S2, the presence / absence of foreign matter is determined based on the detection data DA and DB. That is, the detection data DA and DB are respectively compared with the foreign matter determination reference data Ds. If the detection data DA and DA are less than the reference data Ds (DA <Ds, DB <Ds), the process proceeds to step S3. If the detection data DA, DB is equal to or greater than the reference data Ds (DA ≧ Ds, DB ≧ Ds), the process proceeds to step S5.
In step S3, it is determined that “no foreign matter” and the process proceeds to step S4. In step S4, the operation of the apparatus is continued.
In step S5, it is determined that “foreign matter exists”, and the process proceeds to step S6. In step S6, an arbitrary alarm generation device 11 shown in FIG. 4 is driven to output an alarm, and the drive system 12 of the device is driven to stop the operation.
[0017]
As described above, in the exposure apparatus according to the present embodiment, before performing proximity gap control for forming a minute gap between the exposure surface Pa of the glass substrate P and the pattern Ma of the photomask M, the glass substrate Since the presence / absence of foreign matter is determined for the exposure surface Pa of P and the pattern surface Ma of the photomask M, the presence / absence of foreign matter A and B can be inspected for the exposure surface Pa and the pattern surface Ma. If it is determined that there is a foreign matter, the operation of the apparatus is stopped, so that damage to the pattern and resist film due to the foreign matter A on the exposure surface Pa that occurs when proximity gap control is performed can be prevented. In addition, since it is possible to prevent repeated pattern burn-in defects caused by pattern damage or foreign matter B adhering to the pattern surface Ma, the yield can be improved.
[0018]
In the exposure apparatus according to the present embodiment, when it is determined that “a foreign object is present” for glass substrate P or photomask M, a command for collecting glass substrate P or photomask M is output to control unit 10. An operation unit (not shown) is provided. This operation unit is operated by an operator. For example, when a glass substrate collection command signal is output to the control unit 10, the control unit 10 drives and controls a carry-out arm (not shown) so as to collect the glass substrate P from the exposure chuck 2. When a photomask recovery command signal is output to the control unit 10, the control unit 10 drives and controls the automask changer so that the photomask M is replaced with a new photomask. In the proximity exposure apparatus shown in this embodiment, proximity gap control and alignment are performed on the glass substrate P and the photomask M without foreign matter after the foreign matter inspection described above. Since it is the same as an apparatus, the description is abbreviate | omitted.
[0019]
The proximity exposure apparatus shown in the present embodiment is configured such that the exposure chuck 2 is driven by the stage driving apparatus D and the glass substrate P is moved relative to the photomask M, but is not limited thereto. For example, the mask holder 1 may be driven by an appropriate driving device (not shown) to move the photomask M relative to the glass substrate P. Further, the exposure chuck 2 may be driven by the stage driving device D, the mask holder 1 may be driven by the driving device, and the glass substrate P and the photomask M may be moved relative to each other. Further, as the projectors 6a1 and 7a1 of the light irradiation systems 6a and 7a, white light, two-wavelength lasers, etc. are used as the irradiation light L in order to avoid the influence of the photoresist film forming the exposure surface Pa of the glass substrate P. What emits irradiation light is used suitably.
[0020]
The exposure apparatus according to the present invention can be applied to all proximity exposure apparatuses that employ a batch exposure system, a step exposure system, a scan exposure system, and the like. The exposure apparatus according to the present invention can be applied to a contact exposure apparatus that performs exposure with a photomask and an exposure target substrate in close contact with each other. When the exposure apparatus according to the present invention is applied to a contact exposure apparatus, before the photomask and the exposure target substrate are brought close to each other, as described above, the photomask and the exposure target substrate are relatively moved, and the mask surface is moved. And the exposed surface can be inspected for the presence of foreign matter.
[0021]
【The invention's effect】
As described above, according to the exposure apparatus and the foreign matter inspection method of the present invention, before the pattern surface of the mask and the exposure surface of the exposure target substrate are brought close to each other, the presence or absence of foreign matter is determined on the pattern surface and the exposure surface. Since this is performed, it is possible to inspect the presence of foreign matter on the pattern surface and the exposure surface.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram that shows one embodiment of an exposure apparatus according to the present invention.
FIG. 2 is a view showing an example of detecting foreign matter on an exposure surface by a foreign matter detection system for a glass substrate.
FIG. 3 is a diagram showing an example of detecting foreign matter on a pattern surface by a foreign matter detection system for a photomask.
4 is a block diagram showing an example of a foreign matter determination control system shown in FIG.
FIG. 5 is a flowchart showing an example of foreign object determination processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mask holder 2 Exposure chuck 6 Foreign substance detection system for glass substrate 7 Foreign substance detection system for photomask 10 Control part D Stage drive device M Photomask Ma Pattern surface P Glass substrate Pa Exposure surface

Claims (2)

In an exposure apparatus that performs exposure by bringing the pattern surface of the mask held by the mask holder close to the exposure surface of the exposure target substrate held by the exposure chuck,
Driving means for driving at least one of a mask holder and an exposure chuck so as to relatively move the mask and the exposure target substrate before bringing the pattern surface of the mask close to the exposure surface of the exposure target substrate; ,
While by the drive means and the at least one of the mask holders and the exposure chuck driven relative movement between the exposure target substrate and the mask, respectively the status of said exposure surface of the pattern surface Detection means for optically detecting at the same time ;
Control for determining the presence or absence of foreign matter on the pattern surface based on the output of the detection means corresponding to the pattern surface, and determining the presence or absence of foreign matter on the exposure surface based on the output of the detection means corresponding to the exposure surface And an exposure apparatus having a foreign matter inspection function. In an exposure apparatus that performs exposure by bringing the pattern surface of the mask held by the mask holder close to the exposure surface of the exposure target substrate held by the exposure chuck, the pattern surface and the exposure surface are inspected for foreign matter. A foreign matter inspection method for
Driving at least one of a mask holder and an exposure chuck so as to relatively move the mask and the exposure target substrate before bringing the pattern surface of the mask close to the exposure surface of the exposure target substrate;
While the step by relatively moving the said exposure target substrate and the mask by driving at least one of the exposure chuck and said mask holder, at the same time the state of the state and the exposure surface of the pattern surface, respectively An optical detection step;
A foreign matter inspection method comprising: determining the presence or absence of foreign matter on the pattern surface based on detection data corresponding to the pattern surface, and determining the presence or absence of foreign matter on the exposure surface based on detection data corresponding to the exposure surface.

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