JP2013077683A - Reticle support mechanism and inspection apparatus for reticle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reticle support mechanism in which deformation of a reticle can be suppressed to a minimum, and an inspection apparatus for the reticle.SOLUTION: A reticle support mechanism 1 supporting a reticle 104 is configured by comprising a reticle support stage 102 and an intermediate member 103 placed on the reticle support stage 102, such that the reticle support stage 102 supports the reticle 104 via the intermediate member 103. The reticle support stage 102 supports the reticle 104 at two points using neighboring two corners of the reticle 104, and supports the intermediate member 103 at one point. The intermediate member 103 supports the reticle 104 using two corners different from the two corners of the reticle 104. By using the reticle support mechanism 1, an inspection apparatus 100 is configured.

Description

  The present invention relates to a reticle support mechanism and an inspection apparatus.

  Conventionally, as an inspection method performed when manufacturing a photomask or a reticle (in the present specification, simply referred to as a reticle) used in a photolithography process of semiconductor manufacturing, a reticle is placed on a stage, for example, A method is known in which illumination light is collected and irradiated from the normal direction to inspect the presence or absence of a reticle defect (see, for example, Patent Document 1). In this inspection method, the illumination light transmitted through the reticle or the illumination light reflected by the reticle is imaged on the photodetector through the objective lens, and the presence or absence of pattern defects or foreign matter on the reticle is inspected based on the obtained optical image.

  At this time, a pellicle can be attached to the reticle in order to prevent foreign matter from adhering to the mask. The pellicle is configured by attaching a transparent film to a square frame, and the frame is fixed to the periphery of the pattern on the pattern forming surface of the reticle by bonding or the like.

  In an inspection apparatus that implements the above-described inspection method for a reticle on which such a pellicle is installed, the reticle to be inspected is usually supported using a pattern forming surface on which the pellicle is installed.

JP 2007-322482 A

  In the conventional inspection apparatus, when inspecting a reticle on which a pellicle is installed, it is necessary to use a reticle support base or the like to support the reticle at a portion not covered by the pellicle. Here, the reticle usually has a square or rectangular shape. In such a case, the portions not covered by the pellicle are the four corners of the pattern formation surface of the reticle. Therefore, the four corners are used to support the reticle where the pellicle is installed.

  Incidentally, in order to minimize the deformation of the reticle, it is preferable to support the reticle at three points. However, as described above, in the conventional inspection apparatus, four-point support using the four corners of the pattern forming surface is performed by the reticle support base. In the case of four-point support, a highly accurate height adjustment is required for the support member, and if the height adjustment is insufficient, there is a problem that the reticle is deformed.

  The present invention has been made in view of these problems. That is, an object of the present invention is to provide a reticle support mechanism that can minimize the deformation of the reticle during inspection or the like.

  Another object of the present invention is to provide an inspection apparatus having a reticle support mechanism capable of minimizing the deformation of the reticle during inspection or the like.

  Other objects and advantages of the present invention will become apparent from the following description.

A first aspect of the present invention has a reticle support base that supports a reticle via an intermediate member,
The reticle support base is related to a reticle support mechanism configured to be in contact with the reticle at two points and at one point with the intermediate member.

In the first aspect of the present invention, the reticle support base is in contact with the reticle at two non-diagonal corners among the four corners of the reticle,
The intermediate member is preferably in contact with the reticle at two corners that are diagonally opposite to the two corners where the reticle support member and the reticle are in contact.

  In the first aspect of the present invention, it is preferable that the reticle support base is in contact with the reticle and the intermediate member via ball points.

  In the first aspect of the present invention, an elastic body is preferably provided between the intermediate member and the reticle support.

A second aspect of the present invention is an inspection apparatus having a reticle support mechanism for supporting a reticle to be inspected,
The reticle support mechanism has a reticle support base that supports the reticle via an intermediate member,
The reticle support base is related to an inspection apparatus configured to come into contact with the reticle at two points and with the intermediate member at one point.

  According to the first aspect of the present invention, it is possible to provide a reticle support mechanism that can minimize deformation of the reticle.

  In addition, according to the second aspect of the present invention, it is possible to provide an inspection apparatus having a reticle support mechanism that can minimize deformation of the reticle.

It is a typical side view explaining the structure of the reticle support mechanism of this Embodiment. It is a typical top view explaining the structure of the reticle support stand of the reticle support mechanism of this Embodiment. It is a typical top view explaining the structure of the intermediate member of the reticle support mechanism of this Embodiment. It is explanatory drawing which shows the inspection apparatus of this Embodiment.

<Embodiment 1>
FIG. 1 is a schematic side view for explaining the configuration of the reticle support mechanism of the present embodiment.

  As shown in FIG. 1, the reticle support mechanism 1 according to the present embodiment includes a reticle support base 102 and an intermediate member 103 placed on the reticle support base 102. In the reticle support mechanism 1, the reticle support base 102 supports the reticle 104 to be inspected or the like from below via the intermediate member 103 and holds the reticle 104. A pattern forming surface (not shown) of the reticle 104 is a lower surface in FIG. 1, and a pellicle (not shown) is provided on the pattern forming surface. Therefore, the reticle support mechanism 1 is configured to support and hold the reticle using the pattern forming surface of the reticle 104 on which the pellicle is installed.

  The reticle support base 102 has a frame shape with an opening at the center so that, for example, illumination light for inspection reaches the pattern forming surface of the reticle 104. In addition, reticle support base 102 preferably has a square or rectangular frame shape so as to correspond to the shape of reticle 104 to be supported. The intermediate member 103 is also configured by selecting a shape that does not prevent the illumination light from reaching the pattern formation surface of the reticle 104 when placed on the reticle support 102.

  The reticle support base 102 is not particularly limited as long as it can realize rigidity capable of supporting the reticle 104, and the material used is not particularly limited. For example, it can be configured using stainless steel, titanium metal, aluminum metal, or the like.

  FIG. 2 is a schematic plan view for explaining the structure of the reticle support base of the reticle support mechanism according to the present embodiment.

  As shown in FIG. 1, the reticle support base 102 has a support member 111. The support member 111 can be constituted by, for example, a ball point having a spherical head surface.

  As shown in FIGS. 1 and 2, the reticle support base 102 includes three support members 111- so that the intermediate member 103 and the reticle 104 placed thereon are supported at three points to determine the installation position. 1, 111-2, 111-3 are provided. Of the three support members 111-1 to 111-3 of the reticle support base 102, the two support members 111-1 and 111-2 use two non-diagonal corners among the four corners of the reticle 104. In contact with the reticle 104. Support members 111-1 and 111-2 directly support reticle 104.

  The remaining one support member 111-3 on the reticle support base 102 does not directly support the reticle 104. The support member 111-3 contacts the intermediate member 103 placed on the reticle support base 102, and is configured to support the intermediate member 103 at one location.

  That is, of the three support members 111 of the reticle support base 102, the two support members 111-1 and 111-2 are not opposite to each other among the four corners of the reticle 104, but are adjacent to the reticle 104. To support the reticle 104. Therefore, the two support members 111-1 and 111-2 are disposed on the reticle support base 102 at positions facing the two corners of the reticle 104. That is, the support members 111-1 and 111-2 are arranged at two corners adjacent to each other, not diagonally on the reticle support base 102. The two support members 111-1 and 111-2 may be respectively disposed at two corners positioned at both ends of the side extending in the short direction of the reticle support base 102 that is a rectangular frame-shaped body. preferable. The reticle support base 102 does not support the two corners at the diagonal positions of the reticle 104 by the support member 111.

  The remaining one support member 111-3 of the three support members 111 of the reticle support base 102 is between the two corners of the reticle support base 102 where the support members 111-1 and 111-2 are not arranged. Disposed in the region. That is, the support member 111-3 is, for example, one of two sides extending in the short direction of the reticle support base 102 that is a rectangular frame-like body, and the support members 111-1 and 111-2 are provided at both ends. Is disposed in the region of the central portion of the side opposite to the side on which is disposed.

  The reticle support base 102 is configured to contact the intermediate member 103 with one support member 111-3 and support the intermediate member 103 at one location. As will be described later, the intermediate member 103 is configured to support the two corners of the reticle 104 that are not supported by the support members 111-1 and 111-2. That is, the intermediate member 103 is configured to contact the reticle 104 at two corners that are diagonal to the two corners of the reticle 104 that are in contact with the support members 111-1 and 111-2 of the reticle support base 102, respectively. .

  In reticle support base 102, it is preferable to provide at least one elastic body 112 in the vicinity of support member 111-3 so that the attitude of intermediate member 103 can be maintained when reticle 104 is not placed. That is, in the reticle support mechanism 1, the elastic body 112 is provided between the intermediate member 103 and the reticle support base 102 to maintain the posture of the intermediate member 103. The position where the elastic body 112 is provided is preferably in the vicinity of the support member 111-3 and within a range that does not cause deformation such as the intermediate member 103 holding the posture. The elastic body 112 can be configured using, for example, a coil spring.

  Two elastic bodies 112 can be provided on the reticle support base 102 in the vicinity of the support member 111-3 so as to sandwich the support member 111-3. It is also possible to provide three or more elastic bodies 112 on the reticle support base 102 in the vicinity of the support member 111-3 and around the support member 111-3. As shown in FIG. 2, three elastic bodies 112 may be provided around the supporting member 111-3 so that the deformation of the reticle 104 can be minimized and the posture can be maintained. preferable.

  FIG. 3 is a schematic plan view for explaining the structure of the intermediate member of the reticle support mechanism of the present embodiment.

  The intermediate member 103 is not particularly limited as long as the intermediate member 103 can realize the rigidity capable of supporting the reticle 104 and the material used. The intermediate member 103 can be configured using, for example, stainless steel, titanium metal, aluminum, or the like. The same material as that of reticle support 102 can be used.

  The intermediate member 103 preferably has a shape that supports the reticle 104 by contacting the reticle 104 using two corners of the reticle 104 that are not supported by the support members 111-1 and 111-2. FIG. 3 shows an example of a preferable shape of the intermediate member 103.

  For example, the intermediate member 103 can be a rectangular plate having a length in the longitudinal direction corresponding to the width of the reticle 104. Further, as shown in FIG. 3, the intermediate member 103 is a reticle having a plate-like body having a length in the longitudinal direction corresponding to the width of the reticle 104, and projecting in the lateral direction at both ends thereof. A planar U-shape having a support portion 113 for supporting 104 can be used.

  The intermediate member 103 has a shape that supports the reticle 104 by using two adjacent corners of the reticle 104 that are not supported by the support members 111-1 and 111-2 of the reticle support base 102. As shown in FIGS. 1 and 3, the intermediate member 103 has a support member 114 for supporting the reticle 104 in a region facing the two corners of the reticle 104. The support member 114 is in contact with the reticle 104 using two adjacent corners that are not diagonal to the reticle 104 and supports the reticle 104. The support member 114 can be configured by a ball point having a spherical head surface, for example, as with the support member 111 described above.

  Further, for example, when the intermediate member 103 is a rectangular plate-like body as described above, the support member 114 is disposed at each of both ends thereof. In addition, as shown in FIG. 3, when the intermediate member 103 has a structure having the support portions 113 at both ends, the intermediate members 103 are disposed on the respective support portions 113.

  As shown in FIG. 3, the intermediate member 103 has three support members 114-1, 114-2, 114-3, and has three support members 114-1, 114-2, 114-3. It is preferable that the reticle 104 be in contact with the reticle 104 to support the reticle 104 at three points. In that case, for example, when the intermediate member 103 is a rectangular plate-like body, one support member 114-1 is disposed at one end thereof, and two support members 114 are disposed at the other end. -2 and 114-3 are preferably disposed. Further, when the intermediate member 103 has the structure having the support portion 113, one support member 114-1 is disposed on one of the support portions 113, and two support members are disposed on the other. 114-2 and 114-3 are preferably disposed.

  At this time, in any of the above-described cases, the support members 114-1, 114-2, and 114-3 can be configured by the above-described ball points. Further, only one of the two support members 114-2 and 114-3 provided on one end or one support portion 113 is constituted by a ball point, and the other two support members are vacuum chucks. It is also possible to adopt a structure that is fixed with

  In this way, the intermediate member 103 has a configuration that supports the reticle 104 at three points, and can support the reticle 104 while minimizing deformation of the reticle 104.

  Reticle support mechanism 1 of the present embodiment has the above-described structure, so that the pattern forming surface of reticle 104 is used and intermediate member 103 and reticle 104 are supported by three-point support by reticle support base 102. Is possible. That is, the reticle 104 is directly supported at two points by the reticle support base 102 of the reticle support mechanism 1 and is supported at one point via the intermediate member 103, thereby realizing support at a total of three points. Become. As a result, the reticle support mechanism 1 according to the present embodiment can support the reticle 104 and hold the state while minimizing deformation of the reticle 104.

<Embodiment 2>
FIG. 4 is an explanatory view showing the inspection apparatus of the present embodiment.

  The inspection apparatus 100 of the present embodiment shown in FIG. 4 has the reticle support mechanism 1 of the present embodiment shown in FIG.

  As shown in detail in FIG. 1, the reticle support mechanism 1 includes a reticle support base 102 and an intermediate member 103 placed on the reticle support base 102. As shown in FIGS. 1 and 2, the reticle support base 102 is configured to be in contact with the reticle 104 at two points and at one point with the intermediate member 103. The reticle support mechanism 1 has a structure in which a reticle support base 102 supports a reticle 104 to be inspected or the like via an intermediate member 103. Then, the inspection apparatus 100 inspects the reticle 104 supported by the reticle support mechanism 1. The inspection apparatus 100 can inspect the reticle 104 with a pellicle attached to the pattern formation surface.

The inspection apparatus 100 includes a stage 10 on which the reticle support mechanism 1 that holds the reticle 104 is placed, a movement control unit 20 that controls the movement of the stage 10, and illumination light from the normal direction to the reticle 104 on the reticle support mechanism 1. and illumination means 30 which irradiates an imaging means 40 for imaging the illumination light reflected by the illumination light and the reticle 104 that has passed through the reticle 104 to the optical detector 42 _1, 42 ₂ through the objective lens 41, a photodetector And a processing unit 50 that performs a process for inspecting the reticle 104 for defects and foreign matter based on the optical images obtained by 42 ₁ and 42 ₂ , and an autofocus unit 60 that focuses the objective lens 41 on the reticle 104. ing.

  The stage 10 is moved by motors 11X and 11Y in the X and Y directions, which are two horizontal directions orthogonal to each other, and is rotated by a motor 11θ around a vertical θ axis. Further, a laser length meter 12 for measuring the position of the stage 10 in the X direction and the Y direction is provided. Note that a window hole (not shown) is formed in a portion of the stage 10 where the reticle support mechanism 1 that holds the reticle 104 is placed. Then, the reticle 104 is supported by the reticle support mechanism 1 so that the mounting surface of the pellicle (not shown) faces down, and the reticle support mechanism 1 holding the reticle 104 is placed on the stage 10.

  The movement control means 20 is configured so that the scanning range setting unit 21 connected to the control computer 70 via a bus line and the stage 10 is moved within a scanning range set as will be described later by the scanning range setting unit 21. The motor controller 22 controls the motors 11X, 11Y, and 11θ.

  The illumination means 30 expands the diameter of illumination light such as laser light emitted from the light source 31 to a parallel light flux via lenses 32 and 33, and then supports the illumination light via a mirror 34 and a condenser lens 35 to support a reticle. A transmission illumination system that condenses and irradiates the reticle 104 on the mechanism 1 from above in the vertical direction, which is the normal direction, and illumination light reflected by the half mirror 36 disposed between the lens 33 and the mirror 34. A reflection illumination system that condenses and irradiates the reticle 104 from below in the vertical direction via the half mirror 38 and the objective lens 41.

The imaging means 40 illuminates light (transmitted light) that has been irradiated onto the reticle 104 on the reticle support mechanism 1 from above and transmitted through the reticle 104, and illumination light (reflected light) that has been irradiated onto the reticle 104 from below and reflected by the reticle 104. ) and was incident on the separation mirror 43 through the objective lens 41 and the half mirror 38, the transmitted light with focusing from the separation mirror 43 to the first photodetector 42 ₁ via the lens 44, separating the mirror reflected light An image is formed on the _second photodetector 422 from 43 through the lens 45. As the photodetectors 42 ₁ and 42 ₂ , a TDI sensor, a CCD sensor, a CMOS sensor, or the like can be used. Further, the optical detector ₄₂ 1, 42 ₂ is formed in a rectangular. Then, the photodetector 42 _1, 42 ₂ is the longitudinal direction is arranged along the sub-scanning direction to be described later, so that take wide sub-scanning direction of the scan pitch.

The processing unit 50 includes a comparison unit 51 and a reference unit 52. The reference unit 52 reads the design data of the reticle 104 from the magnetic disk 53 through the control computer 70, and creates a mask pattern image (reference image) based on the design data. The comparison unit 51 includes a reference image, an optical image obtained by the photodetectors 42 ₁ and 42 ₂ , and a position detection unit 54 that is connected to the laser length meter 12 and detects the position of the optical image on the reticle 104. Position data is input. Then, the optical image and the reference image are compared according to a predetermined algorithm, and an inspection process for determining whether or not the reticle 104 on the reticle support mechanism 1 is defective is performed. It is also possible to determine the presence or absence of defects by a method of repeatedly comparing patterns (die-to-die method).

  The autofocus unit 60 includes a focus shift detection unit 62 configured by a confocal optical system that receives reflected light via a half mirror 61 disposed between the half mirror 38 and the separation mirror 43, and a focus shift detection unit 62. And a motor 64 that is controlled by the focus control unit 63 to move the objective lens 41 in the vertical direction. Then, the objective lens 41 is displaced in the vertical direction according to the amount of deviation between the reticle 104 detected by the focus deviation detection unit 62 and the focal point of the objective lens 41, so that the focal point of the objective lens 41 is on the reticle support mechanism 1. Align with reticle 104. The stage 10 may be displaced in the vertical direction instead of the objective lens 41.

  When inspecting the reticle 104, one of the x-axis direction and the y-axis direction, which are two coordinate axis directions orthogonal to each other in a coordinate system fixed to the reticle 104 on the reticle support mechanism 1, for example, the x-axis direction is the main scanning direction. The illumination light is scanned by moving the stage 10 with the y-axis direction as the sub-scanning direction. That is, the illumination light is scanned in the x-axis direction by moving the stage 10 in the X direction, and the scanning position is shifted by a predetermined pitch in the y-axis direction by moving the stage 10 in the Y direction.

  The inspection apparatus 100 of the present embodiment shown in FIG. 4 has the above-described structure, and the reticle support mechanism 1 of the present embodiment placed on the stage 10 has the pattern of the reticle 104 as shown in FIG. Using the formation surface, the intermediate member 103 and the reticle 104 are supported by the reticle support base 102 by three-point support. Therefore, the inspection apparatus 100 can inspect the reticle 104 for pattern defects and foreign matter while holding the reticle 104 while minimizing the deformation of the reticle 104. As a result, the inspection apparatus 100 according to the present embodiment can realize inspection of the reticle 104 with high accuracy.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Reticle support mechanism 10 Stage 11X, 11Y, 11 (theta), 64 Motor 12 Laser length meter 20 Movement control means 21 Scan range setting part 22 Motor control part 30 Illumination means 31 Light source 32, 33, 44, 45 Lens 34, 37 Mirror 35 Condenser Lenses 36, 38, 61 Half mirror 40 Image forming means 41 Objective lenses 42 ₁ , 42 ₂ Photo detector 43 Separating mirror 50 Processing means 51 Comparison section 52 Reference section 53 Magnetic disk 54 Position detection section 60 Autofocus means 62 Defocus detection Unit 63 focus control unit 70 control computer 100 inspection device 102 reticle support base 103 intermediate member 104 reticles 111, 111-1, 111-2, 111-3, 114, 114-1, 114-2, 114-3 support member 112 Elastic body 113 support part

Claims (5)

Having a reticle support for supporting the reticle via an intermediate member;
The reticle support mechanism, wherein the reticle support base is configured to be in contact with the reticle at two points and at one point with the intermediate member. The reticle support base is in contact with the reticle at two non-diagonal corners among the four corners of the reticle,
2. The reticle support mechanism according to claim 1, wherein the intermediate member is in contact with the reticle at two corners that are diagonal to the two corners where the reticle support member and the reticle are in contact with each other. 3.   The reticle support mechanism according to claim 1, wherein the reticle support base is in contact with the reticle and the intermediate member via ball points.   The reticle support mechanism according to claim 1, wherein an elastic body is provided between the intermediate member and the reticle support base. An inspection apparatus having a reticle support mechanism for supporting a reticle to be inspected,
The reticle support mechanism includes a reticle support base that supports the reticle via an intermediate member,
2. The inspection apparatus according to claim 1, wherein the reticle support base is configured to be in contact with the reticle at two points and at one point with the intermediate member.

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