JP2010139593A - Euv (extreme ultraviolet) mask inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress particles from dropping onto a pattern face during inspection. <P>SOLUTION: An EUV mask inspection device 100 includes a stage 7 where an EUV mask 20 is placed in a state that the pattern face 21 of the EUV mask 20 is made upside, and a planar collar 5 to be disposed in parallel with the pattern face 21 to cover the pattern face 21 during inspecting the EUV mask 20. The collar 5 is attached to the periphery of an objective lens 4 condensing the inspection light onto the pattern face 21 of the EUV mask 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mask inspection apparatus (also referred to as a pattern inspection apparatus) used for detecting defects in a photomask (or also referred to as a reticle, which is also referred to as a mask here) used in a semiconductor manufacturing process. In particular, the present invention relates to an EUV mask pattern inspection apparatus used in EUV lithography.

  In lithography technology for miniaturization of semiconductors, ArF lithography using an ArF excimer laser with a wavelength of 193 nm as an exposure light source is currently in mass production. In addition, an immersion technique that fills the space between the objective lens of the exposure apparatus and the wafer with water to increase the resolution is also used, which is called ArF immersion lithography.

  In order to cope with further miniaturization, practical use of EUV lithography (Extremely Ultraviolet Lithography: EUVL) is expected as the next generation lithography of ArF immersion lithography.

  On the other hand, for mask defect inspection, a comparison inspection method between mask patterns and design data (generally called Die-to-Database comparison method) and a pattern comparison inspection method (generally Die-to-Die comparison) between two chips. Two methods are widely known. In any of these inspection methods, a mask pattern image is detected with a microscope.

  In that case, when using an optical microscope, it is necessary to illuminate the mask pattern with light. As the light source (that is, mask inspection light source), a mask inspection apparatus using a continuous laser beam having a wavelength of 257 nm (this is a second harmonic wave having a wavelength of 514 nm, which is the maximum output line of an argon laser) is commercially available. Regarding this, for example, the following Non-Patent Document 1 or 2 shows.

  In the mask inspection system, the mask pattern surface to be inspected faces upward and the objective lens is placed directly above the mask, and conversely the mask pattern surface faces downward and the objective lens is on the lower side of the mask. There is a thing of the structure to arrange. Regarding the former, the structure around the mask is shown in FIG.

  However, the mask 90 shown in FIG. 9 is used in the case of optical lithography such as ArF lithography, and is provided with a pellicle 92 so as to cover the pattern surface 91. The pellicle film 93 is fixed to the mask 90 via a pellicle frame 94. That is, the pellicle frame 94 is bonded to the mask 90 and the pellicle film 93, and a sealed space 95 is formed on the pattern surface 91.

  Therefore, there is no possibility that particles or the like enter this sealed space 95 from the outside. As described above, since the mask for photolithography is provided with the pellicle 92, there is a feature that particles are prevented from adhering to the pattern surface.

  However, the EUV mask used in EUVL is not provided with a pellicle. This is because there is no thin film that transmits X-rays having a wavelength of 13.5 nm, which is an EUVL light source. As a result, when an EUV mask is inspected with the pattern surface facing upward, particles may fall on the pattern surface during the inspection.

  However, as disclosed in Patent Document 1, in general, in a mask inspection apparatus, a filter is disposed on the upper surface, and the structure is such that purified air flows down inside the apparatus. However, there is no guarantee that the particles are always sufficiently suppressed throughout the mask inspection apparatus, and suddenly large particles may fall on the mask. In that case, in an EUV mask without a pellicle, particles fall on the pattern surface, which causes a defect in the exposure process.

  Patent Documents 2 and 3 describe a removable pellicle that is attached to a case for storing the EUV mask for an EUV mask that cannot be operated by attaching a conventional pellicle. It is said that the mask inspection can be performed with the EUV mask still in the case provided with the removable pellicle.

  However, the removal pellicle is not a universal standard product at this time because its shape depends on the case shape and other standards. In addition, even if the shape of the removable pellicle is standardized, in order to realize a mask inspection device that can perform mask inspection with the case equipped with the removable pellicle, a large structure that can be moved in each case within the inspection device There was a problem that it was necessary to remodel.

  Patent Document 4 discloses an inspection apparatus including a ring disk around an objective lens. However, the ring machine of Patent Document 4 is for irradiating illumination light onto the pattern surface, and has a size substantially equal to the pattern surface of the inspection object. For this reason, when the inspection object is scanned and inspected, the inspection object protrudes from the ring board. For this reason, it is impossible to prevent particles from falling.

Proceedings of SPIE Vol. 5446, pp.265-278, 2004 Toshiba Review, Vol. 58, No. 7, pp. 58-61, 2003 JP 2006-352099 A US Pat. No. 6,492,067 US Pat. No. 6,646,720 JP 2008-153321 A

  An object of the present invention is to provide an EUV mask inspection apparatus capable of suppressing the falling of particles onto a pattern surface being inspected.

  An EUV mask inspection apparatus according to a first aspect of the present invention covers a stage on which an EUV mask is placed with the pattern surface of the EUV mask facing upward, and covers the pattern surface during the inspection of the EUV mask. Thus, a flat plate-shaped protective member arranged in parallel to the pattern surface is provided. Thereby, it is possible to prevent particles from falling on the EUV mask.

  An EUV mask inspection apparatus according to a second aspect of the present invention is the above-described inspection apparatus, further comprising an objective lens that condenses inspection light on a pattern surface of the EUV mask, and the protection member includes the objective lens It is characterized by being a collar attached to the periphery of the. Thereby, it is possible to prevent particles from falling on the EUV mask.

  An EUV mask inspection apparatus according to a third aspect of the present invention is the above-described inspection apparatus, wherein the size of the brim is always equal to the entire surface of the EUV mask even when the EUV mask is scanned and inspected. It is the size covered with the brim. Thereby, even when the objective lens is positioned at the extreme end of the EUV mask, the EUV mask is hidden by the flange when viewed from above the EUV mask, so that it is possible to more reliably prevent particles from falling on the EUV mask.

  An EUV mask inspection apparatus according to a fourth aspect of the present invention is the above-described inspection apparatus, further comprising a filter provided on the collar. Thereby, gas can be flowed on an EUV mask through a filter, and it can suppress that a particle etc. flow from the horizontal direction on the pattern surface of an EUV mask.

  An EUV mask inspection apparatus according to a fifth aspect of the present invention is the above-described inspection apparatus, wherein the protective member is a pellicle that is provided so as to surround the EUV mask and is fixed to the stage. It is what. Thereby, it is possible to prevent particles from falling on the EUV mask.

  An EUV mask inspection apparatus according to a sixth aspect of the present invention is the above-described inspection apparatus, further comprising a gas supply mechanism for flowing gas over the pattern surface of the EUV mask. Thereby, the invasion of particles from the side of the EUV mask can be prevented.

  An EUV mask inspection apparatus according to a seventh aspect of the present invention is the above-described inspection apparatus, further comprising a light source that irradiates ultraviolet light onto the pattern surface of the EUV mask. Thereby, the organic foreign matter adhering to the pattern surface of the EUV mask can be decomposed.

  ADVANTAGE OF THE INVENTION According to this invention, the EUV mask inspection apparatus which can suppress the fall of the particle to the pattern surface under test | inspection can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In addition, in the following description, what attached | subjected the same code | symbol has shown substantially the same content.

Embodiment 1 FIG.
The configuration of the EUV mask inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a configuration of an EUV mask inspection apparatus 100 according to the present embodiment. FIG. 2 is a side view of the periphery of the EUV mask 20 in the EUV mask inspection apparatus 200 according to the present embodiment.

  As shown in FIG. 1, an EUV mask inspection apparatus 100 includes an inspection light source 1, a polarizing beam splitter 2, a λ / 4 wavelength plate 3, an objective lens 4, a flange 5, tubes 6a and 6b, a stage 7, a moving table 8, and a projection. A lens 9 and a two-dimensional optical sensor 10 are provided.

  In the EUV mask inspection apparatus 100, ultraviolet light L1 having a wavelength of 193 nm from the inspection light source 1 is used as illumination light. The ultraviolet light L1 enters the polarization beam splitter 2. The ultraviolet light L1 is an S wave, is reflected by the polarization beam splitter 2, and travels downward like the ultraviolet light L2.

  The ultraviolet light L2 passes through the λ / 4 wavelength plate 3 and becomes circularly polarized ultraviolet light L3. The ultraviolet light L3 passes through the objective lens 4 and illuminates the pattern surface 21 of the EUV mask 20. That is, the λ / 4 wavelength plate 3 focuses the ultraviolet light L3 that is the inspection light on the pattern surface 21 of the EUV mask 20.

  The ultraviolet light of the optical image generated from the illuminated pattern surface 21, that is, the ultraviolet light including the optical information in the spatial intensity distribution passes through the objective lens 4 again. Since the ultraviolet light is circularly polarized in the direction opposite to that of the ultraviolet light L3, it passes through the λ / 4 wavelength plate 3 again to become a P wave. For this reason, the ultraviolet light that has become the P wave passes through the polarization beam splitter 2.

  As a result, the ultraviolet light passes through the projection lens 9 and strikes the two-dimensional photosensor 10. That is, the region observed by the objective lens 4 is enlarged and projected on the two-dimensional optical sensor 10. As the two-dimensional optical sensor 10, a CCD or TDI is suitable.

  The stage 7 is provided with a moving table 8. The EUV mask 20 is placed on the moving table 8 so that the pattern surface 21 is on the upper side. The moving table 8 is provided so as to be movable in the horizontal direction of FIG. 1 and in a direction perpendicular to the paper surface. By moving the moving table 8 with the EUV mask 20 placed thereon, the entire pattern surface 21 of the EUV mask 20 can be moved directly below the objective lens 4 so that the entire pattern surface 21 is inspected. It has become.

  A flange 5 is attached around the tip of the objective lens 4. The flange 5 is a flat plate-shaped protective part that is arranged in parallel to the pattern surface 21 so as to cover the pattern surface 21 during the inspection of the EUV mask 20. The collar 5 is arranged in a horizontal orientation immediately above the pattern surface 21 of the EUV mask 20. With this flange 5, particles falling from above during inspection can be prevented from being placed on the pattern surface 21.

  Further, the collar 5 is provided with a gas supply mechanism for flowing gas on the pattern surface 21 of the EUV mask 20. In the present embodiment, the flange 5 is provided with tubes 6a and 6b. The tubes 6a and 6b are provided in the vicinity of the objective lens 4 at positions facing each other with the objective lens 4 interposed therebetween. CDA (Clean Dry Air) is supplied to the tubes 6a and 6b. By supplying CDA from the tubes 6 a and 6 b, CDA flows out between the flange 5 and the pattern surface 21 of the EUV mask 20. Thereby, intrusion of particles from the side of the pattern surface 21 can be prevented.

  Here, the size of the flange 5 will be described with reference to FIG. FIG. 2A shows a case where the pattern surface 21 of the EUV mask 20 is scanned and inspected, and the rightmost end is inspected. When the right end of the pattern surface 21 is inspected as shown in FIG. 2A, the EUV mask 20 is covered with a flange 5 attached to the left side of the objective lens 4. At this time, CDA is supplied only from the tube 6b, and CDA is not supplied from the tube 6a.

  FIG. 2B shows a case where the pattern surface 21 of the EUV mask 20 is scanned and inspected to inspect the leftmost end. When the left end of the pattern surface 21 is inspected as shown in FIG. 2B, the EUV mask 20 is covered with a flange 5 attached to the right side of the objective lens 4. At this time, CDA is supplied only from the tube 6a, and CDA is not supplied from the tube 6b.

  Thus, even if the EUV mask 20 is scanned and inspected, the size of the flange 5 is such that the entire surface of the EUV mask is always covered with the flange 5 and the EUV mask 20 is hidden by the flange 5. That is, when the apparatus is viewed from above, the flange 5 has a rectangular shape that is twice or more the vertical length and the horizontal length of the EUV mask 20, and the objective lens 4 is provided at substantially the center of the flange 5. It is done.

  In this way, even when any part of the pattern surface 21 of the EUV mask 20 is inspected, the entire EUV mask 20 is covered with the flange 5, and thus particles are prevented from adhering to the EUV mask 20. be able to.

Embodiment 2. FIG.
The configuration of the EUV mask inspection apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a side view of the periphery of the EUV mask 20 in the EUV mask inspection apparatus 200 according to the present embodiment. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 3, in the EUV mask inspection apparatus 200, a flange 5 is provided around the tip of the objective lens 4, as in the first embodiment. As described above, the collar 5 is square when the apparatus is viewed from above, and is always large enough to cover the EUV mask 20 when scanned.

  In EUV mask inspection apparatus 200, unlike Embodiment 1, tubes 6a and 6b for forcibly flowing CDA are not attached to flange 5. Instead, the flange 5 is equipped with filters 11a and 11b.

  Although not shown here, the EUV mask inspection apparatus 200 is provided with a casing surrounding the inspection light source 1, the two-dimensional optical sensor 10, and the like. A fan filter unit (FFU) is provided at the top of the housing. Therefore, in the casing of the EUV mask inspection apparatus 200, the cleaned air falls from the top to the bottom.

  For this reason, in the EUV mask inspection apparatus 200 according to the present embodiment, the purified air that flows down from the top to the inside is used and is used between the collar 5 and the pattern surface 21 of the EUV mask 20. To guide you to. Specifically, the purified air falling from above flows between the flange 5 and the pattern surface 21 via the filters 11 a and 11 b provided on the flange 5. Thereby, it can suppress that a particle etc. flow from the horizontal direction on the pattern surface of an EUV mask.

  Note that the configuration other than the brim 5 of the EUV mask inspection apparatus 200 according to the present embodiment can be the same as that shown in FIG.

Embodiment 3 FIG.
The configuration of the EUV mask inspection apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a side view of the periphery of the EUV mask 20 in the EUV mask inspection apparatus 300 according to the present embodiment. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 4, the EUV mask inspection apparatus 300 is also provided with a flange 5 around the tip of the objective lens 4 as in the first embodiment. As described above, the collar 5 is square when the apparatus is viewed from above, and is always large enough to cover the EUV mask 20 when scanned.

  In the EUV mask inspection apparatus 300, unlike the first and second embodiments, an ultraviolet lamp is attached in the vicinity of the objective lens 4 of the collar 5. As shown in FIG. 4, in the present embodiment, two ultraviolet lamps 12a and 12b are attached. Further, as shown in FIG. 4, a reflector 13 is provided on the upper side so that the ultraviolet light travels only in the lower part where the EUV mask 20 is placed.

  Thereby, during the inspection of the EUV mask 20, the pattern surface 21 can be irradiated with ultraviolet light. For this reason, it is possible to decompose and remove foreign substances, particularly organic substances, attached to the pattern surface 21 of the EUV mask 20.

  As the ultraviolet lamps 12a and 12b, elongated cylindrical mercury lamps are suitable. Each of the ultraviolet lamps 12 a and 12 b is preferably longer than the width of the pattern surface 21 of the EUV mask 20. Thus, when the EUV mask 20 is moved by the moving table 8 and scanned, the entire pattern surface 21 can be irradiated with ultraviolet light.

  In general, it is widely known that organic foreign substances are removed by ultraviolet light, and there are cases where an EUV mask is irradiated with laser light from an ultraviolet laser such as an excimer laser. In contrast to the case where ultraviolet laser light is used in this way, it is considered that using an ultraviolet lamp as in the present invention is inappropriate because the light intensity is lowered.

  However, in the present embodiment, by using the structure in which the flange 5 is attached to the objective lens 4 and the ultraviolet lamps 12a and 12b are attached to the flange 5, it becomes easy to make the ultraviolet lamps 12a and 12b EUV mask 20 close to each other. . Thus, since the ultraviolet lamps 12a and 12b are very close to the EUV mask 20, a sufficiently high light intensity can be obtained, and even an ultraviolet lamp can sufficiently remove organic foreign matters.

  Note that the configuration other than the brim 5 of the EUV mask inspection apparatus 200 according to the present embodiment can be the same as that shown in FIG.

Embodiment 4 FIG.
An EUV mask inspection apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5 is a side view of the periphery of the EUV mask 20 in the EUV mask inspection apparatus 400 according to the present embodiment. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 5, in the present embodiment, the particle countermeasure technique is different from the above-described embodiment. In the EUV mask inspection apparatus 400, a large pellicle 14 that hides the entire EUV mask 20 during inspection is placed on the moving table 8.

  The pellicle 14 includes a pellicle frame 15 and a pellicle film 16. The pellicle 14 has a rectangular shape, and a pellicle frame 15 is provided under the surrounding four sides. The lower surface of the pellicle frame 15 is in contact with the upper surface of the moving table 8, and the pellicle film 16 is attached to the upper surface of the pellicle frame 15.

  The EUV mask 20 is disposed in a space formed by the pellicle 14 and the moving table 8. That is, the pellicle film 16 is a flat plate-shaped protective member disposed in parallel to the pattern surface 21 so as to cover the entire surface of the pattern surface 21. Thereby, the fall of the particle to the pattern surface 21 is prevented.

  In the above-described embodiment, the flange 5 attached to the objective lens 4 is provided. In order to prevent particles from adhering to the pattern surface 21, the area of the flange 5 needs to be larger than that of the EUV mask 20. For this reason, it is necessary to provide a space for retracting the flange 5 around the stage 7. However, this embodiment does not require a collar attached to the objective lens 4 as in the embodiments described above. For this reason, the space around the stage 7 can be reduced.

  The portable method of this embodiment using the pellicle 14 covering the entire EUV mask 20 is largely different from the idea of the removable pellicle disclosed in Patent Documents 2 and 3 described above in the following points. Is different.

  The removal pellicle is a pellicle attached to a case storing the EUV mask for an EUV mask that cannot be operated with a conventional pellicle attached. It is said that the mask inspection can be performed with the EUV mask still in the case.

  However, the removal pellicle is not a universal standard product at this time because its shape depends on the case shape and other standards. In addition, even if the shape of the removable pellicle is standardized, in order to realize a mask inspection device that can perform mask inspection with the case equipped with the removable pellicle, a large structure that can be moved in each case within the inspection device There was a problem that it was necessary to remodel.

  On the other hand, in the present invention, the size of the EUV mask is the same as that of the conventional mask (for example, a square having a side of 6 inches), and inspection can be performed by moving only the bare EUV mask. Further, by covering the EUV mask 20 with the pellicle 14 during the inspection, the adhesion of particles can be prevented.

  By the way, in the case of a mask inspection apparatus in which the objective lens is disposed on the lower side with respect to the EUV mask, if the pellicle as in the present invention is to be disposed in the vicinity of the pattern surface of the EUV mask, the pellicle is It is necessary to hold the whole so as not to fall, and there arises a problem that the holding mechanism of the pellicle becomes complicated.

  However, in the EUV mask inspection apparatus 400 of the present invention, the objective lens 4 is arranged on the upper side with respect to the EUV mask 20. Therefore, the pattern surface 21 of the EUV mask 20 can be easily protected by simply placing the pellicle 14 on the moving table 8.

  In the present embodiment, the pellicle film 16 is disposed between the pattern surface 21 of the EUV mask 20 and the objective lens 4. Further, the inspection of the pattern surface 21 is performed through the pellicle film 16. Therefore, a gap for disposing the pellicle film 16 between the pattern surface 21 and the objective lens 4 is necessary, and at least 2 to 3 mm is substantially required. Therefore, the numerical aperture (NA) is smaller in the objective lens 4 than in the above embodiment.

  However, in the case of a mask for optical lithography, the height of the pellicle to be attached is about 6 mm, and the work distance (the distance between the mask pattern surface and the objective lens) needs to be 7 to 8 mm. Compared to this optical lithography mask, this embodiment can reduce the work distance and increase the NA.

  Moreover, in the EUV mask inspection apparatus 400 according to the present embodiment, the timing of covering the pellicle 14 for particle prevention is preferably immediately after the EUV mask 20 is placed in the EUV mask inspection apparatus 400.

  In general, EUV masks are carried in a dedicated mask cassette having airtightness. However, the EUV mask stored in the mask cassette is opened in the EUV mask inspection apparatus 400, and the mask cassette is opened. Immediately after 20 is taken out, the pellicle 41 of the present invention is put on. As described above, the EUV mask 20 pattern surface 21 is hardly disposed in air with many particles.

  Here, an example of covering the pellicle 14 on the EUV mask 20 will be described in detail with reference to FIGS. FIG. 6 is a diagram showing a state in which the EUV mask 20 is placed on the moving table 8. 6A shows a state viewed from the top surface of the moving table 8, and FIG. 6B shows a state viewed from the side surface. FIG. 7 is a diagram showing a configuration of the pellicle 14 according to the present embodiment. FIG. 8 is a view showing a state where the pellicle 14 is put on the EUV mask 20. Here, a mounting table 17 for placing the EUV mask 20 is provided on the moving table 8.

  As shown in FIG. 6, the EUV mask 20 taken out from the mask cassette is mounted on the mounting table 17 on the moving table 8 and fixed by the fixing arm 18. The fixing arm 18 is provided on the side surface of the EUV mask 20. In the example shown in FIG. 6, two fixing arms 18 are provided per side of the rectangular EUV mask 20. The EUV mask 20 is fixed by pressing the fixing arm 18 against the side surface of the EUV mask 20.

  As shown in FIG. 7, the pellicle frame 15 of the pellicle 14 is provided with a notch 19 at a position corresponding to the fixing arm 18. Immediately after the EUV mask 20 is taken out of the mask cassette and mounted on the mounting table 17, the pellicle 14 is put on as shown in FIG.

  In the present embodiment, a gas supply mechanism that allows gas to flow on the pattern surface of the EUV mask may be provided as in the first embodiment. For example, a gas supply hole can be provided in the pellicle frame 15 of the pellicle 14, and CDA can be supplied from the hole. Further, ultraviolet light may be irradiated onto the pattern surface 21 of the EUV mask 20 from above the pellicle film 16. Thereby, an organic foreign material can be removed.

  As described above, the mask inspection apparatus 400 according to the present invention can prevent particles and the like from adhering to the pattern surface 21 while inspecting the EUV mask 20 without the pellicle 14. In particular, when inspecting in a high-sensitivity mode (specifically, an inspection mode for detecting a foreign object having a small pixel size) that requires a long inspection time, the inspection can be performed with peace of mind.

  The present invention is particularly suitable for an inspection apparatus for a pellicleless mask such as an EUV mask. However, the present invention is not limited to an EUV mask, and can also be applied to an imprint mask inspection without a pellicle, or a patterned wafer inspection apparatus. It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention already described.

It is a figure which shows the structure of the EUV mask inspection apparatus which concerns on Embodiment 1. FIG. It is the figure which looked at the EUV mask periphery in the EUV mask inspection apparatus of FIG. 1 from the side. It is the figure which looked at the EUV mask periphery in the EUV mask inspection apparatus which concerns on Embodiment 2 from the side. It is the figure which looked at the EUV mask periphery in the EUV mask inspection apparatus which concerns on Embodiment 3 from the side. It is the figure which looked at the EUV mask periphery in the EUV mask inspection apparatus which concerns on Embodiment 4 from the side. It is a figure which shows the structure of the pellicle which concerns on this Embodiment 4. FIG. In the EUV mask inspection apparatus which concerns on Embodiment 4, it is a figure which shows the state in which EUV mask is mounted on a movement table. In the EUV mask inspection apparatus which concerns on Embodiment 4, it is a figure which shows the state which covered the pellicle on the EUV mask. It is the figure which looked at the mask periphery in the conventional mask inspection apparatus from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inspection light source 2 Polarization beam splitter 3 (lambda) / 4 wavelength plate 4 Objective lens 5 Head 6a, 6b Tube 7 Stage 8 Moving table 9 Projection lens 10 Two-dimensional optical sensor 11a, 11b Filter 12a, 12b Ultraviolet lamp 13 Reflector 14 Pellicle 15 Pellicle Frame 16 Pellicle film 17 Mounting table 18 Fixing arm 19 Notch 20 EUV mask 21 Pattern surface 100 EUV mask inspection device L1 to L3 Ultraviolet light

Claims (7)

A stage on which the EUV mask is placed with the pattern surface of the EUV mask facing upward;
A flat protective member arranged in parallel to the pattern surface so as to cover the entire surface of the pattern surface during the scan inspection of the EUV mask;
An EUV mask inspection apparatus comprising: An objective lens for focusing the inspection light on the pattern surface of the EUV mask;
The EUV mask inspection apparatus according to claim 1, wherein the protection member is a flange attached around the objective lens.   3. The EUV mask inspection apparatus according to claim 2, wherein the size of the brim is such that the entire EUV mask is always covered with the brim even when the EUV mask is scanned and inspected. 4. .   The EUV mask inspection apparatus according to claim 2, further comprising a filter provided on the collar.   The EUV mask inspection apparatus according to claim 1, wherein the protection member is a pellicle that is provided so as to surround the EUV mask and is fixed to the stage.   The EUV mask inspection apparatus according to any one of claims 1 to 5, further comprising a gas supply mechanism that allows a gas to flow on a pattern surface of the EUV mask.   The EUV mask inspection apparatus according to any one of claims 1 to 6, further comprising a light source that irradiates ultraviolet light onto a pattern surface of the EUV mask.

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