WO2017094751A1

WO2017094751A1 - Inspection device

Info

Publication number: WO2017094751A1
Application number: PCT/JP2016/085484
Authority: WO
Inventors: 米澤　良
Original assignee: 株式会社ブイ・テクノロジー
Priority date: 2015-12-04
Filing date: 2016-11-30
Publication date: 2017-06-08
Also published as: TW201727253A; JP6669481B2; KR20180090992A; CN108351312A; TWI700504B; CN108351312B; JP2017102074A; KR102644488B1

Abstract

An inspection device in which a photomask is supported in the vertical direction, wherein the center-of-gravity position of the device can be lowered even when an anti-vibration stage is provided below a surface plate. A substantially cube-shaped recess 10b is formed at each of the four corners of the lower surface 10a of the surface plate 10. The bottom surfaces of the recesses 10b are supported by an anti-vibration stage 51, which is higher than the recess is deep.

Description

Inspection device

The present invention relates to an inspection apparatus.

Patent Document 1 discloses a pattern inspection apparatus that supports a photomask in a vertical direction and inspects a pattern formed on the photomask.

JP 2010-181296 A

In the invention described in Patent Document 1, since the photomask is supported in the vertical direction, the position of the center of gravity of the apparatus becomes higher than that of the apparatus that instructs the photomask in the horizontal direction. As a result, there is a problem that the apparatus is not stable.

Further, in the invention described in Patent Document 1, since the stage is placed directly on the installation surface (for example, the floor), there is a problem that even if vibration occurs when the apparatus is driven, the vibration cannot be suppressed. . In order to suppress the vibration of the apparatus, a vibration isolation table may be provided under the stage. In this case, the position of the center of gravity of the apparatus is further increased.

The present invention has been made in view of such circumstances. In an inspection apparatus that supports a photomask in the vertical direction, the center of gravity of the apparatus can be lowered while providing a vibration isolation table under the surface plate. An object is to provide an inspection device.

In order to solve the above problems, an inspection apparatus according to the present invention is, for example, a mask inspection apparatus that inspects a mask to be inspected supported in a vertical direction, and a lower surface, an upper surface parallel to the lower surface, A surface plate formed such that a distance between the lower surface and the upper surface is shorter than a short side of the upper surface, a column provided on the surface plate so as to protrude upward from the upper surface, An imaging unit provided on a column; and a vibration isolation table placed on an installation surface, and the lower surface is formed with substantially cubic recesses at four corners, and the vibration isolation table includes the recesses The height is higher than the depth, and the bottom surfaces of the recesses are respectively supported by the vibration isolation table.

According to the inspection apparatus of the present invention, substantially cubic concave portions are formed at the four corners on the lower surface of the surface plate, and the bottom surface of the concave portion is supported by the vibration isolation table placed on the installation surface. A board is placed on the installation surface. Thereby, in the inspection apparatus that supports the photomask in the vertical direction, the center of gravity of the apparatus can be lowered while providing the vibration isolation table under the surface plate.

Here, a mask support portion that supports the mask in the vertical direction is provided, and a groove is formed on the upper surface along the longitudinal direction of the surface plate at a position that does not overlap the concave portion in plan view. The support portion may move inside the groove. Thereby, a gravity center position can be made low, maintaining the intensity | strength of a surface plate.

Here, the depth of the recess may be formed to be 0.3 to 0.5 times the distance between the lower surface and the upper surface. Thereby, the strength of the surface plate can be maintained.

Here, the imaging unit is provided movably along the pillar, and the groove is a lower end surface of an opening formed in the mask support unit when the imaging unit abuts on the surface plate. May be formed at such a depth that substantially matches the height of the optical axis of the imaging unit. Thereby, the gravity center position can be made the lowest.

Here, the concave portion includes four first concave portions provided at the four corners of the lower surface, and two second concave portions respectively provided along the long sides of the lower surface, and the second One of the recesses may be formed at a position where a part thereof overlaps a part of the pillar in plan view. Thereby, a 2nd recessed part can be provided in the position nearer to the center of gravity, and as a result, the less distorted second recessed part can support the stone surface plate with less distortion.

Here, the mask support portion has a guide member that moves inside the groove, and the guide member has a bottom air pad that discharges air toward the bottom surface of the groove, and air toward the side surface of the groove. And a guide member main body provided with the bottom surface air pad and the side surface air pad. Thereby, an air layer is formed between the guide member and the groove (side surface and bottom surface). Therefore, the guide member can be easily moved.

Here, the side air pad is a first side air pad fixed to the first side surface of the guide member body, and a second side air pad provided in a hole formed in the second side surface opposite to the first side surface. A second side air pad that is movably provided with respect to the guide member body, the guide member body includes a through-hole formed in the first side air pad, and the second side air pad. A formed through-hole and a flow path for supplying air to the space between the hole and the second side air pad are formed, and the second side air pad is formed between the hole and the second side air pad. The guide member main body may be moved by air supplied to the space. Thereby, the space | interval of the 1st side surface of a groove | channel and the front end surface of a 1st side surface air pad and the space | interval of the 2nd side surface of a groove | channel and the front end surface of a 2nd side surface air pad can be adjusted automatically.

Here, the mask support portion includes a frame that holds the mask, and an adjustment mechanism that is provided on the lower side of the frame and adjusts the height of the frame, and the guide The member main body is provided with a pin penetrating in the vertical direction and having an upper end surface that is substantially hemispherical. The lower end of the pin is provided on the bottom surface air pad, and the upper end is contacted with the bottom surface of the adjustment mechanism. You may touch. Thereby, a heavy mask support part is supported by a highly rigid groove, and an undesired uneven load on the air pad can be avoided.

According to the present invention, in the inspection apparatus that supports the photomask in the vertical direction, the position of the center of gravity of the apparatus can be lowered while providing the vibration isolation table under the surface plate.

It is a front view showing the outline of inspection device 1 concerning a 1st embodiment. 1 is a plan view showing an outline of an inspection apparatus 1. FIG. 1 is a perspective view showing an outline of an inspection apparatus 1. FIG. It is the schematic for demonstrating the guide member 33, and is the top view which expanded the inspection apparatus 1 partially. FIG. 5 is a schematic diagram for explaining a guide member 33, and is a cross-sectional view taken along the line AA in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a front view showing an outline of an inspection apparatus 1 according to the first embodiment. FIG. 2 is a plan view showing an outline of the inspection apparatus 1. FIG. 3 is a perspective view showing an outline of the inspection apparatus 1. In this specification, a direction perpendicular to the paper surface in FIG. 1 is defined as an x direction, a vertical direction on the paper surface is defined as a y direction (vertical direction), and a direction orthogonal to the x direction and the y direction is defined as a z direction. 2 and 3, illustration of a part of the configuration is omitted.

The inspection apparatus 1 is, for example, an inspection apparatus that supports a photomask M to be inspected in a substantially vertical direction, and inspects a pattern or the like formed on the photomask M by moving a camera or the like in the vertical direction.

The photomask M to be inspected in this embodiment is an exposure mask used for manufacturing a substrate for a display device of a liquid crystal display device, for example. The photomask M is obtained by forming one or a plurality of image device transfer patterns on a large, substantially rectangular substrate having a side exceeding, for example, 1 m.

The inspection apparatus 1 mainly includes a surface plate 10, an imaging unit 20, a mask support unit 30, and a vibration isolation table 50 (including vibration isolation tables 51 and 52, see FIG. 3).

The surface plate 10 is configured as a stage and is supported on vibration isolation tables 51 and 52 installed at a plurality of locations (six locations) on the installation surface F.

The surface plate 10 is a substantially rectangular parallelepiped (thick plate) stone member having a width W of about 1200 mm and a thickness T of about 400 mm. In other words, the surface plate 10 has a lower surface 10a and an upper surface 10e parallel to the lower surface 10a, and the distance between the lower surface 10a and the upper surface 10e is shorter than the short side of the upper surface 10e.

On the lower surface 10 a of the surface plate 10,

concave portions

10 b and 10 c having a substantially cubic shape are formed. The recess 10b is formed at one place at each of the four corners of the lower surface 10a. The recessed part 10c is formed in two places, one each along the long side of the lower surface 10a. Thus, the

recesses

10b and 10c are formed in a total of six places. Distortion of the stone surface plate 10 can be reduced by providing the recess 10c in addition to the recess 10b.

Of the two recesses 10c, the recess 10c formed on the + z side is formed at a position overlapping with a part of the column 21 (detailed later) in plan view (when viewed from above (+ y direction)). . Thereby, the recessed part 10c can be provided in the position nearer to the center of gravity, and the distortion of the stone surface plate 10 can be reduced. In addition, the two concave portions 10c are formed at positions that are point-symmetric with respect to the gravity center position G of the inspection apparatus 1 in plan view (see FIG. 2). The recess 10c has a larger lateral dimension (dimension in the x direction) than the recess 10b for maintenance of the vibration isolation table 52 and the like.

In addition, although the recessed part 10c is not essential, in order to provide as many vibration isolation stands 50 as possible, it is desirable to form at least two recessed parts 10c. As in the present embodiment, by forming the recesses 10c one by one along the long side of the lower surface 10a, the stone platen 10 with less distortion can be supported with fewer recesses 10c. Moreover, the recessed part 10c is not limited to the position shown in figure, For example, the position of the x direction of the two recessed parts 10c may differ. However, considering the control of the vibration isolation table 50 and the like, it is desirable that the positions of the two concave portions 10c in the x direction be the same.

A vibration isolation table 51 placed on the installation surface F is provided inside the recess 10b (see FIG. 3). An anti-vibration table 52 placed on the installation surface F is provided inside the recess 10c (see FIG. 3). The bottom surfaces of the

recesses

10b and 10c are support surfaces 10d supported by the vibration isolation tables 51 and 52.

As shown in FIG. 1, the vibration isolation tables 51 and 52 are higher than the depth D1 of the

recesses

10b and 10c. Accordingly, the

vibration isolating bases

51 and 52 support the support surface 10 d, so that the surface plate 10 is placed on the installation surface F via the

vibration isolating bases

51 and 52. The stability of the inspection apparatus 1 is based on the position of the support surface 10d.

In this way, the

concave portions

10b and 10c are formed in the thick surface plate 10, and the vibration isolation tables 51 and 52 are provided inside the

concave portions

10b and 10c, whereby the center of gravity position of the inspection apparatus 1 when the support surface 10d is used as a reference. G becomes lower. The center-of-gravity position G can be lowered by increasing the thickness T of the surface plate 10 or increasing the depth of the

recesses

10b and 10c.

However, the depth D1 of the

recesses

10b and 10c is 0.3 to 0.5 times the thickness T of the surface plate 10 in order to maintain the strength of the surface plate 10.

Further, the depth D1 of the

recesses

10b and 10c, that is, the height of the support surface 10d is set so that the angle θ (see FIG. 1) looking up the center of gravity G of the entire inspection apparatus 1 from the support surface 10d is 60 degrees or less. Is done.

However, it is desirable that the angle at which the center of gravity position G is looked up from the support surface 10d is smaller. In the present embodiment, the

recesses

10b and 10c are formed so that the angle θ at which the center of gravity position G is looked up from the support surface 10d is about 45 degrees.

Further, in the present embodiment, due to the stability of the inspection apparatus 1 and the convenience during transportation and installation, the

recesses

10b and 10c are formed such that the height H1 of the lower surface 10a is about 100 mm.

A groove 10 f is formed on the upper surface 10 e of the surface plate 10. The groove 10f is formed along the longitudinal direction (x direction) of the surface plate 10 at a position that does not overlap with the

recesses

10b and 10c in plan view (see FIG. 2). Thus, by shifting the position of the groove 10f in the horizontal direction and the position of the

recesses

10b and 10c in the horizontal direction, the thickness of the portion below the groove 10f of the surface plate 10 is increased, and the strength of the surface plate 10 is increased. Can be high.

The depth D2 of the groove 10f is sufficiently smaller than the thickness T of the surface plate 10. In the present embodiment, the depth D2 of the groove 10f is about 60 mm, and the thickness of the portion below the groove 10f is about 340 mm. Therefore, even if the groove 10f is formed, the rigidity of the surface plate 10 can be made sufficiently high.

The groove 10f supports the mask support 30 so as to be movable in the x direction. By using the groove 10f as a guide when moving the mask support part 30, the height of the imaging part 20 and the mask support part 30 can be lowered, and thereby the gravity center position G can be lowered.

The depth D2 of the groove 10f is the lower end of the photomask M in which the optical axis ax of the camera 22 when the camera 22a (detailed later) contacts the upper surface 10e is supported by the mask support 30 (detailed later). Is set to match. This state is a state where the gravity center position G is lowest. In the present embodiment, the depth D2 of the groove 10f is about 60 mm, and the height (pass line) H2 of the lower end of the photomask M at this time is about 680 mm.

The imaging unit 20 mainly includes a column 21 provided so as to protrude upward from the surface plate 10, a camera 22 provided on the column 21, and a support unit 23 that supports the mask support unit 30 at the inspection position ( (See FIG. 1).

The pillar 21 is attached to the upper surface 10e so as to protrude upward (+ y direction) from the upper surface 10e. The column 21 is made of ceramic or the like. In order to lower the gravity center position G, the column 21 is preferably hollow.

The camera 22 is a TDI camera which is a CCD camera or a special CCD camera, for example, and has two

cameras

22a and 22b. Two

cameras

22a and 22b are provided adjacent to each other along the y direction. A moving part (not shown) including an air pad (not shown) is provided between the camera 22 and the column 21. The camera 22 is provided in a moving unit (not shown) so that its optical axis ax is parallel to the z-axis.

When the moving unit moves in the vertical direction (y direction), the camera 22 moves in the vertical direction (y direction). The moving unit includes two

cameras

22a and 22b, an initial position where the camera 22a contacts the upper surface 10e of the surface plate 10, and an upper end position where the camera 22b is positioned near the upper end of the column 21 (see the two-dot chain line in FIG. 1). Are moved along the column 21. By adopting a configuration in which the camera 22a can be brought into contact with the upper surface 10e, the gravity center position G can be lowered.

Moreover, the imaging unit 20 includes a transmission illumination light source and a reflection illumination light source (not shown). The transmitted illumination light source is provided on the back side (−z side) of the photomask M, and irradiates so-called g-line (for example, light having a wavelength of 435.84 [nm]). The reflected illumination light source is provided on the surface side (+ z side) of the photomask M and irradiates so-called e-line (for example, light having a wavelength of 546.07 [nm]). The camera 22 simultaneously receives and images the g-line irradiated from the transmitted illumination light source and the e-line irradiated from the reflected illumination light source.

Next, the configuration of the camera 22 will be described. Each of the

cameras

22a and 22b includes an objective lens that converts g-line and e-line into parallel light, and an optical member that separates g-line and e-line that have passed through the objective lens (for example, a polarizing beam splitter and a dichroic filter). Member having both functions), two sets of imaging lenses that respectively image g-line and e-line separated by the optical member, and g-line and e-line imaged by the two sets of imaging lenses, respectively. An imaging device. As described above, the

cameras

22a and 22b can simultaneously image the transmitted light and the reflected light. The

cameras

22a and 22b can use known techniques and will not be described in detail.

However, it is desirable that the camera 22 has two

cameras

22a and 22b provided adjacent to each other in the y direction in case one of the

cameras

22a and 22b breaks down.

The support unit 23 supports the mask support unit 30 so that the mask support unit 30 does not tilt in the horizontal direction when the mask support unit 30 is moved to the inspection position. In addition, since the well-known technique can be used for the support part 23, detailed description is abbreviate | omitted.

The mask support unit 30 supports the photomask M. The mask support unit 30 includes a frame 31, an adjustment mechanism 32, and a guide member 33.

The frame 31 is formed in a frame shape so as to surround the outer periphery of the photomask M supported vertically. The frame 31 supports the photomask M so that the surface (the surface on which the pattern is formed) of the photomask M is parallel to the xy plane.

The adjustment mechanism 32 is provided below the frame 31. The adjustment mechanism 32 changes the position of the lower side of the photomask M in the height direction (y direction). Since the adjustment mechanism 32 is already known, a detailed description thereof will be omitted.

The guide member 33 is a member that moves inside the groove 10f. As shown in FIG. 3, the guide member 33 mainly includes a guide member main body 331,

side air pads

332 and 333, a lower surface air pad 334, and a pin 335.

The guide member main body 331 is a rod-like member on which the frame 31 and the adjustment mechanism 32 are provided. The guide member main body 331 is provided with

side air pads

332 and 333 and pins 335. The guide member main body 331 is provided with a bottom surface air pad 334 via a pin 335.

FIG. 4 is a schematic view for explaining the guide member 33 and is a plan view in which the inspection apparatus 1 is partially enlarged. In FIG. 4, the flow of air is indicated by thick broken line arrows.

Side air pads

332 and 333 are substantially cylindrical members (see FIG. 3). The side air pad 332 is provided on the side surface 331a of the guide member main body 331, and the side air pad 333 is provided on the side surface 331b opposite to the side surface 331a. The front end surface 332a of the side air pad 332 faces the side surface 10g of the groove 10f, and the front end surface 333a of the side air pad 333 faces the side surface 10h of the groove 10f.

The side surface 10g facing the tip surface 332a is a reference surface, and is formed with high accuracy (for example, the surface accuracy is about 2 μm, and the surface accuracy of the side surface 10h that is not the reference surface is about 5 μm). Therefore, the position of the guide member main body 331 in the z direction and the angle with respect to the xz plane are determined by the tip surface 332a facing the side surface 10g with the thin air layer interposed therebetween.

The side surface air pad 332 has a substantially cylindrical coupling portion 332b and a substantially cylindrical air pad portion 332c. The diameter of the coupling portion 332b is smaller than the diameter of the air pad portion 332c. The coupling portion 332b is provided inside a hole 331c formed in the guide member main body 331. An elastic member (for example, an O-ring) 341 is provided between the outer peripheral surface of the coupling portion 332b and the inner peripheral surface of the hole 331c. Further, since the diameter of the coupling portion 332b is smaller than the diameter of the air pad portion 332c, the state where the front end surface of the coupling portion 332b is in contact with the bottom surface of the hole 331c is maintained. Thereby, the angle of the side air pad 332 with respect to the guide member main body 331 is maintained in a constant state.

The side surface air pad 333 includes a substantially circular cylindrical sliding portion 333b and a substantially circular cylindrical air pad portion 333c. The diameter of the sliding part 333b is smaller than the diameter of the air pad part 333c. The sliding portion 333b is provided in a hole 331d having a diameter larger than the diameter of the sliding portion 333b so as to be movable with respect to the guide member body 331 (details will be described later). An elastic member 342 is provided between the outer peripheral surface of the sliding portion 333b and the inner peripheral surface of the hole 331d so that the supplied air does not escape (detailed later).

In the

side air pads

332 and 333, through

holes

332d and 333d are formed, respectively. In the through

holes

332d and 333d,

orifices

332e and 333e are formed. The through

holes

332d and 333d are connected to a tubular hole 331e formed in the guide member main body 331. The hole 331e is a passage for air supplied from a pump (not shown), one end is covered with a plug 343, and the other end is connected to a pipe 351 connected to the pump or the like. As a result, air is supplied to the space between the hole 331d and the sliding portion 333b and the through

holes

332d and 333d via the pipe 351.

The air supplied to the through-hole 332d passes through the orifice 332e and is discharged toward the side surface 10g from the opening on the tip surface 332a side of the through-hole 332d (see the thick broken line arrow in FIG. 4). The air supplied to the through-hole 333d passes through the orifice 333e and is discharged from the opening on the distal end surface 333a side of the through-hole 333d toward the side surface 10h (see thick broken line arrow in FIG. 4). Thereby, a thin air layer is formed between the side surface 10 g and the front end surface 332 a of the side air pad 332 and between the side surface 10 h and the front end surface 333 a of the side air pad 333.

The air supplied to the space between the sliding portion 333b and the hole 331d presses the distal end surface 333f of the sliding portion 333b, and moves the sliding portion 333b in the normal direction (z direction) of the side surface 331b. . As the sliding portion 333b moves in the z direction, the distance between the side surface 10g and the tip surface 332a and the distance between the side surface 10h and the tip surface 333a are automatically adjusted. For example, when the width of the groove 10f is wide, the side surface air pad 333 is moved in the direction in which the side surface air pad 333 protrudes from the guide member main body 331 (−z direction), and the front end surface 333a of the side surface air pad 333 is brought closer to the side surface 10h.

City area of _{S PI} of the distal end surface 333f, through holes 332d, when the pressure of the air discharged with _{P PI} from 333d, the sliding portion 333b, i.e. the force f exerted on the side air pad _333, and _{S PI} and _{P PI} Product (f = S _PI × P _PI ). In order to move the side air pad 333 to the width of the groove 10f is a side air pads 333, i.e., it is necessary to reduce the area _{S PI} of the front end surface 333f than the area _{S Pd} of the distal end surface 333a. In the present embodiment, the area _SPI is about 0.5 to 0.8 times the area _SPd .

Area of the side surface air pads 332, i.e. the distal end surface 332a is the same area _{S Pd} as the area of the distal end surface 333a, the guide member body 331 is automatically positioned in the groove 10f is maintained.

At this time, since the diameter of the sliding portion 333b is smaller than the diameter of the hole 331d, the central axis of the sliding portion 333b is the central axis of the hole 331d (the normal direction of the side surface where the hole 331d of the guide member main body 331 is formed). Can be tilted against. Therefore, even when the side surface 10g and the side surface 10h are not parallel, the side surface 10g and the front end surface 332a can be made parallel, and the side surface 10h and the front end surface 333a can be made parallel.

The side

surface air pads

332 and 333 spread the side surface of the groove 10f through the thin air layer formed between the side surface 10g and the front end surface 332a and between the side surface 10h and the front end surface 333a. Since the groove 10f is made of stone and does not change in size, the

side air pads

332 and 333, that is, the guide member 33 are guided by the groove 10f.

In the form shown in FIG. 4, since air is supplied from the hole 331e to the space between the sliding portion 333b and the hole 331d and the through hole 333d, the pressure of the air that presses the distal end surface 333f, and the through hole Although the pressure of the air supplied to 333d is the same, the pressure of the air applied to the distal end surface 333f may be different from the pressure of the air supplied to the through hole 333d. For example, the air flow path supplied from the hole 331e in the space between the sliding portion 333b and the hole 331d is partially different from the air flow path supplied from the hole 331e to the through-hole 333d, and Different regulators may be provided in different portions.

The lower surface air pad 334 is a substantially rectangular member in plan view (viewed from the top (+ y direction)), and is provided on the lower side (−y side) of the guide member main body 331 via a pin 335 (see FIGS. 3 and 5). Provided. The lower surface air pad 334 has a tubular through hole 334a formed therein. The through hole 334a is a passage for air supplied from a pump or the like (not shown). One end of the through hole 334a opens to the lower surface 334c (see FIG. 5), and the other end opens to the side surface 334d. An opening portion opened to the side surface 334d of the through hole 334a is connected to a pipe 352 connected to a pump or the like. As a result, air is supplied to the through hole 334a through the pipe 352.

FIG. 5 is a schematic diagram for explaining the guide member 33, and is a cross-sectional view taken along the line AA in FIG. In FIG. 5, the air flow is indicated by thick dashed arrows.

The pin 335 is a rod-like member having a substantially hemispherical surface in the vertical direction. The pin 335 penetrates the guide member main body 331 in the vertical direction (y direction). In the present embodiment, a male screw (not shown) is formed on the outer peripheral surface of the pin 335, and this male screw is a female screw (not shown) formed in a hole 331f penetrating the guide member main body 331 in the y direction. ). Thereby, the pin 335 is fixed to the guide member main body 331.

The lower end of the pin 335 is provided in a hole 334e formed in the upper surface of the lower air pad 334. The bottom surface of the hole 334e is substantially hemispherical, and the bottom surface of the hole 334e and the substantially hemispherical surface at the lower end of the pin 335 are in contact with each other.

The upper end of the pin 335 is an end surface 335a which is a substantially hemispherical surface. The end surface 335 a contacts the bottom surface 32 a of the adjustment mechanism 32. In the present embodiment, the end surface 335a abuts on the recess 32b formed on the bottom surface 32a. Since the end surface 335a is substantially hemispherical, even if the adjustment mechanism 32 is inclined with respect to the pin 335, the position of the adjustment mechanism 32 can be determined with respect to the position of the end surface 335a, and is inconvenient for the

air pads

332 and 334. Uneven load can be avoided. The recess 32b is not essential, and the shape of the recess 32b is not limited to this.

The pin 335 is provided for each lower surface air pad 334. Therefore, the frame 31 and the adjustment mechanism 32 are supported by the two lower surface air pads 334 via the two pins 335.

An orifice 334b is formed inside the through hole 334a. The air supplied from the pipe 352 (see FIG. 4) to the through hole 334a passes through the orifice 334b and is discharged from the opening on the lower surface 334c side of the lower surface air pad 334 toward the bottom surface 10i of the groove 10f. As a result, a thin air layer is formed between the bottom surface 10i and the bottom surface 334c by the air discharged from the through hole 334a (see the broken line arrow in FIG. 5). Accordingly, the lower surface air pad 334, that is, the guide member 33 is lifted from the bottom surface of the groove 10f against the weight of the frame 31, the adjustment mechanism 32, the photomask M, and the like. Thus, the heavy frame 31 and the adjustment mechanism 32 can be supported by the highly rigid groove 10f.

Return to the explanation of Figs. As shown in FIG. 3, the vibration isolation table 50 includes a vibration isolation table 51 that is an active vibration isolation table, and a vibration isolation table 52 that is a passive vibration isolation table supported by weight.

The vibration isolation table 52 has a passive spring element that can move in the z direction. The anti-vibration table 51 is provided on the anti-vibration table 52 with

actuators

51a and 51b movable in the x-direction and y-direction, respectively, and sensors provided in the

actuators

51a and 51b for controlling the

actuators

51a and 51b ( (Not shown) and a control circuit (not shown) for controlling the

actuators

51a and 51b so as to suppress vibrations input from the outside based on a signal from a sensor (not shown) are added. Since the vibration isolation tables 51 and 52 are already known, a detailed description thereof will be omitted.

As shown in FIG. 1, since the vibration isolation tables 51 and 52 support the support surface 10d, the height of the vibration isolation tables 51 and 52 is higher than the depth D1 of the

recesses

10b and 10c. The diameter of the vibration isolation tables 51 and 52 is equal to or less than the length of the side of the support surface 10d. As a result, the vibration isolation bases 51 and 52 are accommodated in the

recesses

10b and 10c, so that space can be saved. However, the diameter of the vibration isolation tables 51 and 52 may not be less than or equal to the length of the sides of the

recesses

10b and 10c.

Next, the operation of the inspection apparatus 1 will be described. First, the photomask M is attached to the frame 31, and the position of the lower side of the photomask M in the height direction (y direction) is adjusted by the adjusting mechanism 32. At this time, the mask support portion 30 is located at an attachment position near the end of the surface plate 10 in the + direction.

Next, the guide member 33 is moved in the −x direction along the groove 10f, and the photomask M is moved from the mounting position to the inspection position.

Specifically, air is supplied to the

side air pads

332 and 333 from a pump (not shown) of the guide member 33 and the air is discharged from the through

holes

332d and 333d. Further, air is supplied to the lower surface air pad 334 from a pump or the like (not shown) of the guide member 33, and the air is discharged from the through hole 334a.

Then, a force in the −x direction is applied to the guide member main body 331 by a drive mechanism (for example, a linear motor) (not shown) of the guide member 33. Since air layers are formed between the

side air pads

332 and 333 and the side surfaces 10g and 10h of the groove 10f and between the lower surface air pad 334 and the bottom surface 10i of the groove 10f, a force is applied to the guide member main body 331. As a result, the guide member 33 can be easily moved.

When the photomask M moves to the inspection position, the image mask 20 inspects the photomask M. In the present embodiment, g-line is simultaneously emitted from the transmitted illumination light source and e-line is emitted from the reflected illumination light source, and these are simultaneously received and imaged by the

cameras

22a and 22b. Then, the difference between the two images is obtained by subtracting the image captured by the camera 22a from the image captured by the camera 22b, thereby finding a pattern defect or the like. However, the method of finding a pattern defect or the like is not limited to this. For example, a pattern defect or the like may be found by comparing each of the image captured by the camera 22a and the image captured by the camera 22b with an image generated based on the design data.

Thus, by performing an inspection using an image by transmitted light and an image by reflected light, the inspection can be performed quickly and various defects can be found.

First, this inspection is performed at an initial position where the camera 22a contacts the upper surface 10e of the surface plate 10. The imaging unit 20 irradiates the transmission illumination light source, the reflection illumination light source, and the

cameras

22a and 22b upward (+ y direction) along the column 21 while simultaneously irradiating the transmission illumination light source with g-line and the reflection illumination light source with e-line. Move. In this manner, the pattern formed on the photomask M supported by the mask support unit 30 is sequentially imaged.

Thus, when the images are taken while moving the

cameras

22a and 22b from the initial position to the upper end position, the imaging unit 20 returns the

cameras

22a and 22b to the initial position. Then, the guide member 33, that is, the photomask M is moved in the −x direction by a predetermined distance. Similarly, the imaging unit 20 captures an image while moving the

cameras

22a and 22b.

The entire surface of the photomask M can be inspected by repeating such an operation. The moving speed in the vertical direction of the

cameras

22a and 22b and the moving speed in the horizontal direction of the guide member 33 are adjusted according to the field of view range and performance of the

cameras

22a and 22b.

When the inspection of the entire surface of the photomask M is completed, a force in the + x direction is applied to the guide member main body 331 by a drive mechanism (not shown) of the guide member 33 to move the mask support portion 30 to the mounting position. Then, the photomask M is replaced, and the next photomask M inspection is started.

According to the present embodiment, the

recesses

10b and 10c are formed on the lower surface 10a of the surface plate 10, and the vibration isolation tables 51 and 52 placed on the installation surface F are the bottom surfaces (support surfaces 10d) of the

recesses

10b and 10c. , The gravity center position G of the inspection apparatus 1 when the support surface 10d is used as a reference can be lowered. Since the inspection apparatus 1 supports the photomask M in the vertical direction, the gravity center position G tends to be high. However, by providing the vibration isolation tables 51 and 52 inside the

recesses

10b and 10c, the center of gravity G of the inspection apparatus 1 can be lowered while providing the vibration isolation tables 51 and 52 below the surface plate 10. . Further, since the vibration isolation tables 51 and 52 are provided, the vibration resistance of the inspection apparatus 1 can be increased. Further, by providing the vibration isolation tables 51 and 52 inside the

recesses

10b and 10c, the inspection apparatus 1 can be saved in space.

For example, when the vibration isolation tables 51 and 52 are provided on the lower side of the surface plate where no concave portion is formed, the gravity center position G becomes high. In addition, when the vibration isolation tables 51 and 52 are provided outside the surface plate where no concave portion is formed, the outer shape of the inspection apparatus becomes large. On the other hand, by forming the

recesses

10b and 10c on the thick surface plate 10 and providing the vibration isolation tables 51 and 52 inside the

recesses

10b and 10c, the inspection apparatus 1 can be made smaller while the center of gravity G is lowered. it can.

Further, according to the present embodiment, the groove 10f is formed on the upper surface 10e of the surface plate 10 at a position that does not overlap with the

recesses

10b and 10c in plan view, so that the center of gravity position G is maintained while maintaining the strength of the surface plate 10. Can be lowered. For example, if a rail is formed on the upper surface 10e of the surface plate 10 and a mask support portion is provided thereon, the center of gravity position G is increased. On the other hand, the center of gravity position G can be lowered by providing the mask support 30 in the groove 10f.

Further, according to the present embodiment, in order to form the groove 10f, the air is discharged from the

side air pads

332 and 333 and the lower surface air pad 334, so that the gap between the

side air pads

332 and 333 and the side surfaces 10g and 10h of the groove 10f is obtained. In addition, an air layer can be formed between the lower surface air pad 334 and the bottom surface 10i of the groove 10f. Thereby, the guide member 33 can be lifted from the groove 10f, and the guide member 33 can be easily moved. Such a configuration and effect can be realized only by directly forming the groove 10 f in a hard material called the surface plate 10.

For example, when a ceramic or stone convex rail is formed on the upper surface 10e of the surface plate 10 and a mask support portion is provided on the rail, the rigidity is low and the dimensional accuracy is lowered. There is a problem that the installation position becomes high. On the other hand, when the groove 10f is formed on the surface plate 10, the rigidity is high and the dimensional accuracy is also high. Therefore, the guide member 33 can be moved smoothly with less vibration. Furthermore, since the groove 10f is strong, air can be discharged from the through

holes

332d, 333d, and 334a with high pressure. Therefore, the guide member 33 can be reliably floated from the groove 10f, and the guide member 33 can be moved more smoothly. In addition, by forming the groove 10f in the surface plate 10, the installation position of the mask support portion 30 can be lowered.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included. .

Further, in the present invention, “substantially” is a concept that includes not only a case where they are exactly the same but also errors and deformations that do not lose the identity. For example, the substantially cubic shape is not limited to a strictly cubic shape. For example, the surface plate 10 is formed with a recess 10b and the like, but the surface plate 10 as a whole has a substantially cubic shape. Further, for example, in the case where the expression is simply vertical, coincidence, etc., not only strictly vertical, coincidence, but also the case of substantially vertical, substantially coincidence, etc. is included.

Further, in the present invention, the “neighborhood” is a concept indicating that when it is in the vicinity of A, for example, it is near A and may or may not contain A.

1: Inspection apparatus 10: Surface plate 10a:

Lower surface

10b, 10c: Recess 10d: Support surface 10e: Upper surface 10f:

Groove

10g, 10h: Side surface 10i: Bottom surface 20: Imaging unit 21: Pillar 22:

Cameras

22a, 22b: Camera 23 : Support portion 30: mask support portion 31: frame 32: adjustment mechanism 32a: bottom surface 32b: concave portion 33: guide member 50: vibration isolation table 51: vibration isolation table 51a, 51b: actuator 52: vibration isolation table 331: guide member main body 331a: Side 331b: Side 331c: Hole 331d: Hole 331e: Hole 331f: Hole 332: Side air pad 332a: Tip surface 332b: Coupling portion 332c: Air pad portion 332d: Through hole 332e: Orifice 333: Side air pad 3 33a: tip surface 333b: sliding portion 333c: air pad portion 333d: through hole 333e: orifice 333f: tip surface 334: bottom air pad 334a: through hole 334b: orifice 334c: bottom surface 334d: side surface 334e: hole 335: pin 335a: end surface 343: Plugs 341, 342: Elastic members 351, 352: Pipe M: Photomask

Claims

A mask inspection apparatus for inspecting a mask to be inspected supported in a substantially vertical direction,
A platen having a lower surface and an upper surface parallel to the lower surface, the distance between the lower surface and the upper surface being shorter than the short side of the upper surface;
A pillar provided on the upper surface so as to protrude upward from the upper surface;
An imaging unit provided on the pillar;
A vibration isolation table placed on the installation surface;
With
On the lower surface, concave portions each having a substantially cubic shape are formed at the four corners,
The vibration isolation table is higher than the depth of the recess,
The inspection apparatus characterized in that the bottom surfaces of the recesses are each supported by the vibration isolation table.
A mask support part for supporting the mask in a substantially vertical direction;
On the upper surface, a groove along the longitudinal direction of the surface plate is formed at a position that does not overlap the concave portion in plan view,
The inspection apparatus according to claim 1, wherein the mask support part moves inside the groove.
The inspection apparatus according to claim 1 or 2, wherein the depth of the concave portion is formed to be 0.3 to 0.5 times the distance between the lower surface and the upper surface.
The imaging unit is provided to be movable along the pillar,
The groove is configured such that when the imaging unit comes into contact with the surface plate, the height of the lower end surface of the opening formed in the mask support unit substantially matches the height of the optical axis of the imaging unit. The inspection apparatus according to claim 2, wherein the inspection apparatus is formed with a depth.
The recess has four first recesses provided at the four corners of the lower surface, and two second recesses provided respectively along the long side of the lower surface,
5. The inspection apparatus according to claim 1, wherein one of the second recesses is formed at a position where a part thereof overlaps a part of the column in plan view.
The mask support portion has a guide member that moves inside the groove,
The guide member includes a bottom surface air pad that discharges air toward the bottom surface of the groove, a side surface air pad that discharges air toward the side surface of the groove, a guide member body provided with the bottom surface air pad and the side surface air pad, The inspection apparatus according to claim 2, further comprising:
The side air pad is a first side air pad fixed to the first side surface of the guide member main body, and a second side air pad provided in a hole formed in the second side surface opposite to the first side surface, A second side air pad provided movably with respect to the guide member body,
Air is supplied to the guide member body through a through hole formed in the first side air pad, a through hole formed in the second side air pad, and a space between the hole and the second side air pad. A flow path is formed,
The inspection apparatus according to claim 6, wherein the second side air pad is moved relative to the guide member main body by air supplied to a space between the hole and the second side air pad.
The mask support portion includes a frame that holds the mask, and an adjustment mechanism that is provided on the lower side of the frame and adjusts the height of the frame,
The guide member main body is provided with a pin penetrating in the vertical direction, the upper end surface being a substantially hemispherical surface,
The inspection device according to claim 6 or 7, wherein the pin has a lower end provided on the bottom surface air pad and an upper end contacting the bottom surface of the adjustment mechanism.