Examination method, and examination device

Abstract

To provide an examination method and an examination device that can improve examination accuracy and through-put.SOLUTION: An examination method according the present embodiment comprises: a segment step of segmenting a stripe area SA into an autofocus area AF and a non-focus area NF in an examination area 85 on a sample 80; and a scan step of, when causing an image-capturing position of the sample 80 to scan, causing the image-capturing position to scan while causing focus-on processing in the autofocus area AF, and causing the focus-on processing to limit in the non-focus area NF. The examination method further comprises: a focus information acquisition step of acquiring focus information in a specific stripe area SA1; and a trajectory generation step of generating a movement trajectory of the non-focus area NF on the acquired focus information. The scan step is configured to move a position of an objective lens 131 on the basis of the movement trajectory to thereby cause the focus-on processing to limit from a position to be determined by the movement trajectory.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an inspection method and an inspection apparatus. [Background technology]

[0002] Patent Document 1 discloses a technology for dividing an area into areas where focusing is performed and areas where focusing is not performed according to attributes of an inspection surface of a sample to be inspected, such as a photomask, and performing focusing on the areas where focusing is performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-078164 A Summary of the Invention [Problem to be solved by the invention]

[0004] Depending on the movement trajectory when moving through the non-focused area, smooth focus tracking may not be possible when switching from the non-focused area to the area where focusing is required. Therefore, in order to achieve both inspection accuracy and throughput, it is important to appropriately determine the movement trajectory of the non-focused area.

[0005] The present disclosure has been made in consideration of such problems, and provides an inspection method and an inspection apparatus capable of improving inspection accuracy and throughput. [Means for solving the problem]

[0006] An inspection method according to one aspect of the present embodiment includes a division step of dividing an inspection area including a plurality of stripe areas extending in one direction on a sample into an autofocus area and an out-of-focus area, and a scanning step of scanning an imaging position of the sample imaged by an imaging unit including an objective lens facing the sample along the stripe area, in the autofocus area, a focusing process is performed to adjust the focus by changing a relative position between the objective lens and the sample along an optical axis direction of the objective lens based on focus state information output from a focusing unit that detects a focus state of the objective lens, and in the out-of-focus area, the focusing process is restricted and the out-of-focus area is scanned, The method further includes a focus information acquisition step in which the imaging position scans at least two of the autofocus regions that sandwich the out-of-focus region in a specific stripe region to perform the focusing process, thereby acquiring focus information including position information of the objective lens that focuses on the sample, and a trajectory generation step in which a movement trajectory of the out-of-focus region in the specific stripe region is generated based on the focus information acquired in the focus information acquisition step, wherein in the scanning step, the position of the objective lens is changed in the optical axis direction of the objective lens in the out-of-focus region in the stripe region based on the movement trajectory generated in the trajectory generation step, and the focusing process is limited from the position determined by the movement trajectory.

[0007] In the above inspection method, the focus information acquisition step may acquire the focus information of the specific stripe region by scanning the imaging position over the specific stripe region and performing the focusing process, and the division step may divide the specific stripe region into the autofocus region and the out-of-focus region based on the focus information of the specific stripe region acquired in the focus information acquisition step.

[0008] In the above inspection method, the trajectory generation step may generate the movement trajectory of the out-of-focus area in the specific stripe area by performing interpolation data processing on the focus information of the two autofocus areas that sandwich the out-of-focus area acquired in the focus information acquisition step.

[0009] In the above inspection method, the division step divides adjacent stripe regions along adjacent stripes adjacent to a specific stripe into the autofocus region and the out-of-focus region corresponding to the division for the specific stripe region, and the scanning step may limit the focusing process while scanning the out-of-focus region in the adjacent stripe region in a direction opposite to the scanning of the specific stripe region in the one direction based on the movement trajectory of the out-of-focus region in the specific stripe region generated in the trajectory generation step.

[0010] In the above inspection method, the division step divides a third stripe region along a third stripe that is not adjacent to the specific stripe and is adjacent to the adjacent stripe, into the autofocus region and the out-of-focus region corresponding to the division for the specific stripe region, and the trajectory generation step generates the movement trajectory for the out-of-focus region in the adjacent stripe region based on the focus information acquired in the scanning step for the adjacent stripe region, which is focus information for two autofocus regions that sandwich the out-of-focus region in the adjacent stripe region, and the scanning step may limit the focusing process while scanning the out-of-focus region in the third stripe region based on the movement trajectory generated for the adjacent stripe.

[0011] In the above inspection method, the division step may divide the stripe regions other than a specific stripe region into the autofocus region and the out-of-focus region corresponding to the division for the specific stripe region, and the scanning step may scan the stripe region along the (i+2n)th stripe in the same direction as the scanning of the specific stripe region in the one direction, and scan the stripe region along the (i+2n+1)th stripe in an opposite direction to the scanning of the specific stripe region in the one direction, where the specific stripe is an i-th stripe, and limit the focusing process while scanning the out-of-focus region in the (i+2n)th stripe region in the same direction based on the movement trajectory of the out-of-focus region in the specific stripe region generated in the trajectory generating step, and limit the focusing process while scanning the out-of-focus region in the (i+2n+1)th stripe region in the opposite direction based on the movement trajectory of the out-of-focus region in the specific stripe region generated in the trajectory generating step.

[0012] In the above inspection method, the focus information may include brightness at the imaging position focused on the sample.

[0013] In the above inspection method, the focusing process includes an auxiliary focusing process that keeps the amount of change in the relative position between the objective lens and the sample along the optical axis direction of the objective lens within a predetermined range caused by vibration of the sample, and a main focusing process that does not keep the amount of change within the predetermined range, and the scanning step may restrict the focusing process from a position determined by the movement orbit by prohibiting at least the main focusing process in the out-of-focus region in the stripe region.

[0014] The above inspection method includes a determination step of determining a type of the out-of-focus region, and the scanning step may, when the type of the out-of-focus region in the stripe region is a predetermined first type, prohibit the auxiliary focusing process and prohibit the main focusing process, thereby restricting the focusing process from a position determined by the movement trajectory, and when the type of the out-of-focus region is not the first type, allow the auxiliary focusing process and prohibit the main focusing process, thereby restricting the focusing process from a position determined by the movement trajectory.

[0015] In the above inspection method, the determination step may include determining, when the out-of-focus region includes a groove-shaped black border surrounding multiple dies formed on the sample and a scribe between the dies formed on the sample, the black border to be the first type and determining the scribe to be a predetermined type different from the first type; determining, when the out-of-focus region includes the black border and a unique part formed on the sample that shows a larger change in position than the change in actual position, the black border to be the first type and determining the unique part to be the predetermined type different from the first type; and determining, when the out-of-focus region includes the black border, the scribe, and the unique part, the black border to be the first type and determining at least one of the scribe and the unique part to be the predetermined type different from the first type.

[0016] An inspection apparatus according to one aspect of the present embodiment includes an imaging section including an objective lens facing a sample, the imaging section imaging the sample, a scanning section causing the imaging section to scan an imaging position of the sample imaged by the imaging section, a focusing section detecting a focus state of the objective lens and outputting detected focus state information, and outputting focus information including position information of the objective lens focused on the sample, the focusing section performing a focusing process to adjust the focus by changing a relative position of the objective lens and the sample along an optical axis direction of the objective lens, and a control section for controlling the imaging section, the scanning section, and the focusing section, the control section dividing an inspection area including a plurality of stripe areas extending in one direction on the sample into an autofocus area and an out-of-focus area, and controlling the imaging section to scan the imaging position of the sample imaged by the imaging section along the stripe areas. When performing the focusing, in the autofocus region, the focus unit performs the focusing process by changing the relative position in the optical axis direction of the objective lens based on the focus state information, and in the out-of-focus region, the focusing process is restricted and the scanning unit is caused to scan, and the imaging position scans at least two of the autofocus regions that sandwich the out-of-focus region in a specific stripe region among the multiple stripe regions to perform the focusing process, thereby acquiring the focus information, generating a movement trajectory for the out-of-focus region in the specific stripe region based on the acquired focus information, and in the out-of-focus region in the stripe region, the position of the objective lens is changed in the optical axis direction of the objective lens based on the generated movement trajectory, and the focusing process is restricted from the position determined by the movement trajectory.

[0017] In the above-mentioned inspection device, the control unit may scan the specific stripe region at the imaging position and perform the focusing process to obtain focus information for the specific stripe region, and divide the specific stripe region into the autofocus region and the out-of-focus region based on the focus information of the specific stripe region.

[0018] In the above inspection device, the control unit may generate the movement trajectory of the out-of-focus area in the specific stripe area by performing interpolation data processing on the focus information of the two autofocus areas that sandwich the acquired out-of-focus area.

[0019] In the above-mentioned inspection device, the control unit may divide an adjacent stripe region along an adjacent stripe adjacent to a specific stripe into the autofocus region and the out-of-focus region corresponding to the division for the specific stripe region, and limit the focusing process while scanning the out-of-focus region in the adjacent stripe region in a direction opposite to the scanning of the specific stripe region in the one direction based on the generated movement trajectory of the out-of-focus region in the specific stripe region.

[0020] In the above inspection device, the control unit may divide a third stripe region along a third stripe that is not adjacent to the specific stripe and is adjacent to the adjacent stripe, into the autofocus region and the out-of-focus region corresponding to the division for the specific stripe region, generate the movement trajectory for the out-of-focus region in the adjacent stripe region based on the focus information acquired in the adjacent stripe region, which is the focus information for the two autofocus regions that sandwich the out-of-focus region in the adjacent stripe region, and limit the focusing process while scanning the out-of-focus region in the third stripe region based on the movement trajectory generated for the adjacent stripe region.

[0021] In the above inspection apparatus, the control unit may divide the stripe regions other than a specific stripe region into the autofocus region and the out-of-focus region corresponding to the division for the specific stripe region, and when the specific stripe is the i-th stripe, scan the stripe region along the (i+2n)-th stripe in the same direction as the scanning of the specific stripe region in the one direction, scan the stripe region along the (i+2n+1)-th stripe in an opposite direction to the scanning of the specific stripe region in the one direction, and limit the focusing process while scanning the out-of-focus region in the (i+2n)-th stripe region in the same direction based on the movement trajectory of the out-of-focus region in the generated specific stripe region, and limit the focusing process while scanning the out-of-focus region in the (i+2n+1)-th stripe region in the opposite direction based on the movement trajectory of the out-of-focus region in the generated specific stripe region.

[0022] In the above inspection apparatus, the focus information may include brightness at the imaging position focused on the sample.

[0023] In the above-mentioned inspection apparatus, the focusing process includes an auxiliary focusing process that keeps the amount of change in the relative position between the objective lens and the sample along the optical axis direction of the objective lens within a predetermined range caused by vibration of the sample, and a main focusing process that does not keep the amount of change within the predetermined range, and the control unit may restrict the focusing process from a position determined by the movement orbit by prohibiting at least the main focusing process in the out-of-focus region in the stripe region.

[0024] In the above inspection device, the control unit may determine the type of the out-of-focus area, and if the type of the out-of-focus area in the stripe area is a predetermined first type, prohibit the auxiliary focusing process and prohibit the main focusing process, thereby restricting the focusing process from a position determined by the movement trajectory, and if the type of the out-of-focus area is not the first type, allow the auxiliary focusing process and prohibit the main focusing process, thereby restricting the focusing process from a position determined by the movement trajectory.

[0025] In the above inspection apparatus, when the out-of-focus region includes a groove-shaped black border surrounding multiple dies formed on the sample and a scribe between the dies formed on the sample, the control unit determines the black border to be the first type and determines the scribe to be a predetermined type different from the first type; when the out-of-focus region includes the black border and a unique portion formed on the sample that shows a larger change in position than the actual change in position, the control unit determines the black border to be the first type and determines the unique portion to be the predetermined type different from the first type; when the out-of-focus region includes the black border, the scribe, and the unique portion, the control unit determines the black border to be the first type and determines at least one of the scribe and the unique portion to be the predetermined type different from the first type. Effect of the Invention

[0026] According to the present disclosure, it is possible to provide an inspection method and an inspection device that can improve inspection accuracy and throughput. [Brief description of the drawings]

[0027] [Figure 1] 1 is a configuration diagram illustrating an inspection device according to a first embodiment. [Diagram 2]2 is a plan view illustrating a sample in the inspection device according to the first embodiment. FIG. [Diagram 3] 1 is a cross-sectional view illustrating a sample in the inspection device according to the first embodiment. [Figure 4] 1 is a graph illustrating the Z-axis position of the objective lens and the brightness at the imaging position when focusing is performed on the entire area of ​​a specific stripe region in the inspection device of embodiment 1, where the horizontal axis indicates the Y-axis position and the vertical axis indicates the Z-axis position of the objective lens and the brightness at the imaging position. [Diagram 5] 1 is a graph illustrating the Z-axis position of the objective lens and the brightness at the imaging position when focusing is performed over the entire area of ​​a specific stripe region in the inspection device of embodiment 1, where the horizontal axis indicates the Y-axis position and the vertical axis indicates the Z-axis position and brightness. [Figure 6] 1 is a graph illustrating the Z-axis position of the objective lens and the brightness at the imaging position when focusing is performed over the entire area of ​​a specific stripe region in the inspection device of embodiment 1, where the horizontal axis indicates the Y-axis position and the vertical axis indicates the Z-axis position and brightness. [Figure 7] 1 is a graph illustrating a moving trajectory generated for the entire area of ​​a specific stripe region and the brightness of the imaging position in the inspection device of embodiment 1, where the horizontal axis indicates the position in the Y-axis direction and the vertical axis indicates the position and brightness in the Z-axis direction. [Figure 8] 2 is a plan view illustrating a sample in the inspection device according to the first embodiment. FIG. [Figure 9] FIG. 2 is a flow chart illustrating an inspection method according to the first embodiment. [Figure 10] FIG. 2 is a flow chart illustrating an inspection method according to the first embodiment. [Figure 11] FIG. 2 is a flow chart illustrating an inspection method according to the first embodiment. [Figure 12] FIG. 11 is a configuration diagram illustrating an inspection device according to a second embodiment. [Figure 13] FIG. 11 is a configuration diagram illustrating an inspection device according to a fourth embodiment. [Figure 14]FIG. 11 is a configuration diagram illustrating an inspection device according to a fourth embodiment. [Figure 15] 13 is a diagram illustrating an example of a movement mode of a light spot formed on a photodetector in the inspection device according to the fourth embodiment. FIG. [Figure 16] 13 is a diagram illustrating an example of a movement mode of a light spot formed on a photodetector in the inspection device according to the fourth embodiment. FIG. [Figure 17] 13 is a diagram illustrating an example of a movement mode of a light spot formed on a photodetector in the inspection device according to the fourth embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The following description shows a preferred embodiment of the present disclosure, and the scope of the present disclosure is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same contents.

[0029] (Embodiment 1) An inspection device and an inspection method according to the first embodiment will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating an inspection device according to the first embodiment. As shown in FIG. 1, the inspection device 1 according to this embodiment includes a stage 110, an illumination optical system 120, an imaging unit 130, a scanning unit 140, a focusing unit 150, and a control unit 160. For example, the inspection device 1 is an inspection device that detects defects present in a sample 80 such as a photomask.

[0030] <Stage> The stage 110 supports the sample 80 to be inspected. Here, for convenience in explaining the inspection apparatus 1, an XYZ Cartesian coordinate system is introduced. One direction, for example, the vertical direction, is defined as the Z-axis direction. A plane perpendicular to one direction, for example, the horizontal plane, is defined as the XY plane. Furthermore, the upper side is defined as the +Z-axis direction side, and the lower side is defined as the -Z-axis direction side. Note that the vertical direction, upper side, lower side, etc. are for convenience in explaining the inspection apparatus 1, and do not indicate the directions in which the actual inspection apparatus 1 is placed.

[0031] The stage 110 may be configured as an XY stage that can be moved in the X-axis direction and the Y-axis direction by the scanning unit 140. The stage 110 moves in the X-axis direction and the Y-axis direction to scan the imaging position of the sample 80 imaged by the imaging unit 130. Note that, as will be described later, the scanning unit 140 may scan the imaging position of the sample 80 imaged by the imaging unit 130 by moving the imaging unit 130 instead of moving the sample 80 on the stage 110.

[0032] <Sample> In this embodiment, a photomask such as an EUV mask will be used as an example of the sample 80 to be inspected. The sample 80 may include various substrates such as mask blanks, semiconductor substrates, and glass substrates in addition to the photomask. The sample 80 is placed on a stage 110. FIG. 2 is a plan view illustrating the sample 80 in the inspection device 1 according to the embodiment 1. FIG. 3 is a cross-sectional view illustrating the sample 80 in the inspection device 1 according to the embodiment 1.

[0033] 2, the sample 80 includes an inspection area 85 when viewed from the +Z axis direction. The inspection area 85 is, for example, rectangular. The inspection area 85 may also be a quadrangle having sides extending in the X axis direction and the Y axis direction. Note that the shape of the inspection area 85 when viewed from the +Z axis direction is not limited to a quadrangle.

[0034] As shown in FIGS. 2 and 3, the inspection region 85 includes a first region 81, a second region 82, a third region 83, and a fourth region 84. The first region 81 includes, for example, a region in which a plurality of dies are formed. The second region 82 includes a groove-shaped black border that surrounds the plurality of dies formed on the sample 80. The black border includes a frame portion that surrounds the plurality of dies. The second region 82 is formed in a rectangular frame shape that is spaced apart from the four sides of the inspection region 85. The first region 81 includes a central portion surrounded by the second region 82, and portions between the four sides of the inspection region 85 and the second region 82.

[0035] The third region 83 includes scribes between dies formed on the sample 80. The fourth region 84 includes a unique portion that exhibits a change in position that is larger than the change in actual position formed on the sample 80. The unique portion includes, for example, an absorber of a mask formed at a higher density than a predetermined density.

[0036] A plurality of stripes STR are set in the inspection area 85. The plurality of stripes STR are set so as to extend in the Y-axis direction, for example. Each stripe STR extends from an end of the inspection area 85 on the +Y-axis direction side to an end on the -Y-axis direction side. Each stripe STR functions as a line that scans an imaging position on the sample 80 imaged by the imaging section 130. The interval between adjacent stripes STR may be, for example, several hundreds of μm, or may be smaller or larger than that. The plurality of stripes STR may include a first (1st) stripe STR, a second (2nd) stripe STR, and a third (3rd) stripe STR.

[0037] The first stripe STR is represented by an arrow extending in the -Y-axis direction. The first stripe STR may be referred to as a specific stripe STR1. The second stripe STR is represented by an arrow extending in the +Y-axis direction. The second stripe STR may be referred to as an adjacent stripe STR2. The adjacent stripe STR2 is adjacent to the specific stripe STR1. The third stripe STR is represented by an arrow extending in the -Y-axis direction. The third stripe STR may be referred to as a third stripe STR3. The third stripe STR3 is not adjacent to the specific stripe STR1 but is adjacent to the adjacent stripe STR2.

[0038] The inspection area 85 includes a plurality of stripe areas SA. The stripe areas SA include an area on the sample 80 along the stripe STR. Thus, the stripe areas SA extend in one direction. The stripe areas SA include an imaging position where the imaging unit 130 images the sample. The width of the stripe areas SA, i.e., the length of the stripe areas SA in the X-axis direction, may be, for example, several hundreds of μm, or may be smaller or larger than that. Thus, the inspection area 85 includes a plurality of stripe areas SA along the plurality of stripes STR extending in one direction on the sample 80. Each stripe area SA may include a first area 81, a second area 82, a third area 83, and a fourth area 84. The area on the sample 80 along the specific stripe STR1 is called a specific stripe area SA1. Also, the area on the sample 80 along the adjacent stripe STR2 is called an adjacent stripe area SA2. Furthermore, the area on the sample 80 along the third stripe STR3 is called a third stripe area SA3. The stripe areas SA are areas scanned by the imaging unit 130, and are sometimes called scan areas or scan lines.

[0039] <Illumination optical system> The illumination optical system 120 illuminates the sample 80 with illumination light L101. In Fig. 1, the illumination light L101 is diagrammatically indicated by an arrow. The illumination optical system 120 includes an illumination light source 121, a field stop 122, and a non-polarizing beam splitter 123. The illumination optical system 120 may include optical members other than those described above.

[0040] The illumination light source 121 generates illumination light L101 for inspection. In this embodiment, the illumination light L101 includes linearly polarized S-polarized light. The illumination light L101 is incident on a field stop 122.

[0041] The field stop 122 has CAF slits 122a, slits 122b, and slits 122c. A λ / 2 plate is attached to the slit 122c. The illumination light L101 that passes through the CAF slit 122a is called beam B101. The illumination light L101 that passes through the slit 122b is called beam B102. The illumination light L101 that passes through the slit 122c is called beam B103. The beam B101 becomes the illumination light L101 for autofocus. The beams B102 and B103 become the illumination light L101 for inspection. The illumination light L101 emitted from the field stop 122 includes beams B101, B102, and B103. Both the beams B101 and B102 include S-polarized light. On the other hand, the beam B103 includes P-polarized light.

[0042] When inspecting a sample 80 such as an EUV mask, illumination light L101 including S-polarized light and P-polarized light is used. This improves the detection sensitivity of minute patterns along the vertical and horizontal directions on the pattern surface of the EUV mask. In order to reflect both S-polarized light and P-polarized light, illumination light L101 is reflected by a non-polarizing beam splitter 123.

[0043] Non-polarizing beam splitter 123 reflects a portion of the S-polarized light and a portion of the P-polarized light, while transmitting a portion of the S-polarized light and a portion of the P-polarized light. Illumination light L101 reflected by non-polarizing beam splitter 123 is incident on objective lens 131 in imaging section 130.

[0044] <Imaging unit> The imaging section 130 captures an image of the sample 80. The imaging section 130 includes an objective lens 131, a mirror 132, a half mirror 133, a lens 134, an image sensor 135, an amplifier 136, and a signal processing device 137. The imaging section 130 may include members other than those described above. The objective lens 131 faces the sample 80.

[0045] The illumination light L101 incident on the objective lens 131 is condensed by the objective lens 131 and illuminates the sample 80. The illumination light L101 is reflected by the sample 80 and becomes reflected light R101, which passes through the objective lens 131.

[0046] The reflected light R101 reflected by the sample 80 includes S-polarized beams B101 and B102, and P-polarized beam B103. That is, the reflected light R101 includes the autofocus beam B101, and the inspection beams B102 and B103. A part of the reflected light R101 that has passed through the objective lens 131 passes through the non-polarizing beam splitter 123. The reflected light R101 that has passed through the non-polarizing beam splitter 123 is reflected by the mirror 132. The reflected light R101 that has been reflected by the mirror 132 enters the half mirror 133.

[0047] The half mirror 133 reflects a part of the reflected light R101 to a half mirror 151 of the focusing unit 150, and transmits a part of the reflected light R101 to a lens 134 of the imaging unit 130. The reflected light R101 transmitted through the lens 134 includes the inspection beam B102 and beam B103. The reflected light R101 is collected by the lens 134 and an image is formed by the imaging element 135.

[0048] Specifically, the imaging element 135 includes a detector such as a TDI (Time Delay Integration) sensor or a CMOS sensor. An image signal output from the imaging element 135 is amplified by an amplifier 136 and supplied to a signal processing device 137. The signal processing device 137 forms an image of the sample 80 using the image signal output from the imaging element 135. The signal processing device 137 detects defects present in the sample 80 by, for example, die-to-die comparison. It is also possible to use a die-to-database method as a method for detecting defects.

[0049] <Scanning section> The scanning unit 140 scans the imaging position of the sample 80 imaged by the imaging unit 130. In the inspection device 1 of this embodiment, the imaging unit 130 is fixed, and the stage 110 holding the sample 80 is moved in the X-axis direction and the Y-axis direction by the scanning unit 140. In this way, the inspection device 1 scans the imaging position of the sample 80 imaged by the imaging unit 130. The imaging position may be detected by the position sensor 141. The detected imaging position is output to the control unit 160. Note that the inspection device 1 may fix the stage 110 holding the sample 80, and move the imaging unit 130 in the X-axis direction and the Y-axis direction by the scanning unit 140, thereby scanning the imaging position. The scanning unit 140 includes, for example, a member having a driving function such as an actuator. The scanning unit 140 scans the imaging position along a plurality of linear stripes STR extending in the Y-axis direction.

[0050] <Focus section> The focusing unit 150 detects the focus state of the objective lens 131. Then, the focusing unit 150 outputs focus state information including the detected focus state of the objective lens 131 to the control unit 160. The focusing unit 150 also outputs focus information including position information of the objective lens 131 focused on the sample 80 to the control unit 160. The focusing unit 150 performs a focusing process to adjust the focus of the objective lens 131 by changing the relative position of the objective lens 131 and the sample 80 along the optical axis direction of the objective lens 131. The objective lens 131 is supported so as to be movable along its optical axis direction.

[0051] Instead of the objective lens 131 being supported so as to be movable along its optical axis, the stage 110 holding the sample 80 may be made movable along the optical axis of the objective lens 131. In this case, a driving unit 155 of the focusing unit 150 moves the stage 110. The focusing unit 150 has a half mirror 151, a light receiving unit 152, a light receiving unit 153, a processing device 154, a driving unit 155, and a position sensor 156.

[0052] The reflected light R101 incident on the half mirror 151 includes a beam B101 for autofocus. The reflected light R101 incident on the half mirror 151 is transmitted or reflected by the half mirror 151. The light receiving unit 152 is disposed at a position that serves as a front focus of an image formed by the beam B101. The light receiving unit 152 receives the beam B101 that has transmitted through the half mirror 151. The light receiving unit 152 outputs information on the received beam B101 to a processing device 154. On the other hand, the light receiving unit 153 is disposed at a position that serves as a back focus of an image formed by the beam B101. The light receiving unit 153 receives the beam B101 reflected by the half mirror 151. The light receiving unit 153 outputs information on the received beam B101 to the processing device 154.

[0053] The processing device 154 applies feedback control to move the objective lens 131 or the sample 80 so that the intensities of the beam B101 received by the light receiving unit 152 and the light receiving unit 153 become equal. This allows autofocusing and focus adjustment.

[0054] The driving unit 155 is attached to the objective lens 131. The driving unit 155 includes a member having a driving function, such as an actuator. Specifically, the driving unit 155 may use an actuator including a piezoelectric element. The amount of displacement of the objective lens 131 in the optical axis direction is controlled by a driving voltage signal applied to the piezoelectric element. In this way, the driving unit 155 moves the position of the objective lens 131 along the optical axis direction. The driving unit 155 may be attached to the stage 110 that holds the sample 80. Then, the driving unit 155 may move the stage 110 along the optical axis direction of the objective lens 131. In this way, the driving unit 155 can change the relative positions of the objective lens 131 and the sample 80.

[0055] The position sensor 156 is attached to the objective lens 131. The position sensor 156 detects the position of the objective lens 131 in the optical axis direction. In this embodiment, the position sensor 156 uses, for example, a combination of a Z-axis scale and a linear encoder. The position sensor 156 detects the height of the objective lens 131 in the optical axis direction by using an output signal from the linear encoder. The control unit 160 acquires the relative position between the objective lens 131 and the sample 80 based on position information output from at least one of the position sensor 156 and the position sensor 141.

[0056] <Control Unit> The control unit 160 controls the stage 110, the illumination optical system 120, the imaging unit 130, the scanning unit 140, and the focusing unit 150. The control unit 160 may include an information processing device such as a PC (Personal Computer) or a server. The control unit 160 controls the division of the stripe region SA and the scanning of the stripe region SA. The control unit 160 also controls the acquisition of focus information for each stripe region SA such as the specific stripe region SA1, the adjacent stripe region SA2, and the third stripe region SA3, and the generation of the movement trajectory of each stripe region SA. In the following, each operation of the control unit 160 will be described as <division>, <acquisition of focus information>, <trajectory generation>, and <scanning>. Thereafter, the operation of the control unit 160 in the stripe region SA other than the adjacent stripe region SA2, the third stripe region SA3, and the specific stripe region SA1 will be described as <adjacent stripe region>, <third stripe region>, and <stripe region other than the specific stripe region>.

[0057] <Category> The control unit 160 divides the stripe regions SA in an inspection region 85 including a plurality of stripe regions SA extending in one direction on the sample 80 into an autofocus region and an out-of-focus region. For example, the control unit 160 may divide the first region 81 into the autofocus region and the second region 82 into the out-of-focus region. The control unit 160 may divide at least one of the second region 82, the third region 83, and the fourth region 84 into the out-of-focus region. Specifically, the following three methods can be mentioned as a method for dividing the stripe region SA into the autofocus region AF and the out-of-focus region NF.

[0058] One method is as follows: First, the control unit 160 performs focusing on the entire area of ​​a predetermined stripe area SA. This is called a pre-scan. The pre-scan may be performed on a specific stripe area SA1.

[0059] Figure 4 is a graph illustrating the Z-axis position of the objective lens 31 and the brightness at the imaging position when focusing is performed on the entire area of ​​the specific stripe region SA1 in the inspection device 1 of embodiment 1, where the horizontal axis indicates the Y-axis position and the vertical axis indicates the Z-axis position of the objective lens 31 and the brightness at the imaging position.

[0060] As shown in FIG. 4, the control unit 160 scans the imaging position over the specific stripe region SA1 and performs a focusing process. As a result, the control unit 160 acquires focus information over the entire specific stripe region SA. The focus information may include the luminance at the imaging position in addition to the Z-axis position of the objective lens 131 focused on the sample 80. The Z-axis position of the objective lens 131 and the luminance value at the imaging position are significantly different from other values ​​in the second region 82. The Z-axis position of the objective lens 131 in the second region 82 and the luminance value at the imaging position show a change larger than a predetermined change threshold. Therefore, the control unit 160 classifies the second region 82 showing such a large change in the inspection region 85 as an out-of-focus region NF, and the first region 81 showing no large change as an autofocus region AF. The control unit 160 may classify only by the change in the Z-axis position of the objective lens 131 or only by the change in luminance at the imaging position. Furthermore, the control unit 160 may classify, as an autofocus area NF, an area in which the position of the objective lens 131 in the Z axis direction is outside a range of a predetermined threshold and an area in which the brightness of the imaging position is outside a predetermined threshold.

[0061] For the sake of simplicity, the inspection region 85 includes the first region 81 and the second region 82, and excludes the third region 83 and the fourth region 84. When the third region 83 and the fourth region 84 are included, the third region 83 and the fourth region 84 may be classified as an out-of-focus region NF, similar to the second region 82. In addition, the threshold value of the predetermined change in the third region 83 and the fourth region 84 may be a value different from that in the second region 82, or the third region 83 and the fourth region 84 may be classified separately from the second region 82. For example, in the inspection device of the second embodiment described later, the second region 82, the third region 83, and the fourth region 84 may be distinguished when performing auxiliary focusing by the auxiliary focusing unit.

[0062] In this manner, the control unit 160 may divide the specific stripe region SA1 into an autofocus region AF and an out-of-focus region NF based on the focus information of the specific stripe region SA1.

[0063] Another method is to divide the stripe area SA into an autofocus area AF and an out-of-focus area NF based on design data. Specifically, the control unit 160 divides the first area 81 into an autofocus area AF and the second area 82 into an out-of-focus area NF based on previously obtained design data.

[0064] Furthermore, another method is to scan the imaging position in the stripe region SA and divide the region while processing the data. That is, in scanning, when the change in the Z-axis direction position of the objective lens 131 and the change in brightness at the imaging position are equal to or smaller than a predetermined threshold, the control unit 160 divides the region into an autofocus region AF. On the other hand, when the change in the Z-axis direction position of the objective lens 131 and the change in brightness at the imaging position are larger than a predetermined threshold, the control unit 160 divides the region into an out-of-focus region NF.

[0065] The method of dividing the stripe area SA into the autofocus area AF and the out-of-focus area NF is not limited to the above-mentioned method.

[0066] <Get focus information> The control unit 160 causes the imaging position to scan two autofocus areas AF sandwiching at least an out-of-focus area NF in the stripe area SA, and causes a focusing process to be performed, thereby acquiring focus information. The control unit 160 may also cause the imaging position to scan two autofocus areas AF sandwiching at least an out-of-focus area NF in a specific stripe area SA1 among the multiple stripe areas SA, and acquire focus information. Furthermore, when acquiring focus information, the control unit 160 may cause a focusing process to be performed for the entire area of ​​the specific stripe area SA1.

[0067] <Trajectory generation> The control unit 160 generates a movement trajectory of the out-of-focus area NF in the stripe area SA based on the acquired focus information in two autofocus areas AF that sandwich the out-of-focus area NF.

[0068] 5 and 6 are graphs illustrating the Z-axis position of the objective lens 131 and the brightness at the imaging position when focusing is performed over the entire specific stripe region SA1 in the inspection device 1 according to the first embodiment, where the horizontal axis indicates the Y-axis position and the vertical axis indicates the Z-axis position and brightness. Fig. 5 shows the autofocus region AF and the out-of-focus region NF divided by the control unit 160. Fig. 6 shows the movement trajectory generated by the control unit 160.

[0069] As shown in Fig. 5, for example, the control unit 160 first removes the data portion of the out-of-focus area NF. Next, as shown in Fig. 6, the control unit 160 performs curve fitting on the data of the position of the objective lens 131 in the autofocus area AF in the Z-axis direction. The curve fitting may be performed using an appropriate fitting method such as the least squares method. In this way, the control unit 160 generates a movement trajectory for the entire area of ​​the specific stripe area SA1.

[0070] The movement trajectory includes the movement trajectory of the out-of-focus area NF, which is a portion from which data has been removed. That is, when generating the movement trajectory, the control unit 160 performs interpolation data processing on the focus information of the two autofocus areas AF that sandwich the acquired out-of-focus area NF. In this way, the control unit 160 generates the movement trajectory of the out-of-focus area NF in the specific stripe area SA1. The interpolation data processing may use a moving average, or may use a gradient and least squares method.

[0071] <Scan> When the control unit 160 causes the scanning unit 140 to scan the imaging position in the stripe region SA along the stripe region SA, the control unit 160 causes the focusing unit 150 to perform focusing processing in the autofocus region AF by changing the relative position between the objective lens 131 and the sample 80 along the optical axis direction of the objective lens 131 based on the focus state information output from the focusing unit 150. On the other hand, in the out-of-focus region NF, the control unit 160 causes the scanning unit 140 to scan while restricting the focusing processing.

[0072] Figure 7 is a graph illustrating the movement trajectory generated for the entire area of ​​a specific stripe region SA1 in the inspection device 1 of embodiment 1, and the brightness of the imaging position, where the horizontal axis indicates the position in the Y-axis direction and the vertical axis indicates the position and brightness in the Z-axis direction.

[0073] As shown in Fig. 7, when the control unit 160 causes the scanning unit 140 to scan the imaging position in the stripe area SA, in the out-of-focus area NF, the control unit 160 changes the position of the objective lens 131 along the optical axis direction of the objective lens 131 based on the generated movement trajectory, thereby restricting the focusing process. That is, in the autofocus area AF, the control unit 160 moves the objective lens 131 without using the movement trajectory while causing the focusing unit 150 to perform the focusing process of the objective lens 131 as needed, and in the out-of-focus area NF, the control unit 160 moves the position of the objective lens 131, for example, based on the movement trajectory, and restricts the focusing process from the position determined by the movement trajectory. Note that the control unit 160 may use the movement trajectory in the autofocus area AF as an initial position for focusing, and move the objective lens 131 while performing the focusing process as needed.

[0074] Therefore, it is possible to suppress a sudden change in the position of the objective lens 131 at the boundary between the autofocus area AF such as the first area 81 and the out-of-focus area NF such as the second area 82. This makes it possible to improve the inspection accuracy and throughput. The out-of-focus area NF may include not only the second area 82 but also at least one of the third area 83 and the fourth area 84.

[0075] <adjacent stripes> The control unit 160 may perform scanning of the adjacent stripe region SA2 in the opposite direction to that of the specific stripe region SA1 while regarding the adjacent stripe region SA2 as having the same configuration as the specific stripe region SA1. If it is acceptable to add a movement to return the imaging position, scanning may be performed in the same manner as the specific stripe region SA1. This is because, in the inspection region 85, when the second region 82 extends in the X-axis direction, the adjacent stripe region SA2 along the adjacent stripe STR2 adjacent to the specific stripe STR1 in the X-axis direction can be considered to have the same configuration as the specific stripe region SA1.

[0076] First, the control unit 160 divides the adjacent stripe region SA2 along the adjacent stripe STR2 adjacent to the specific stripe STR1 into an autofocus region AF and an out-of-focus region NF in correspondence with the division for the specific stripe region SA1. That is, the adjacent stripe region SA2 included in the Y coordinate range equivalent to the Y coordinate range divided into the autofocus region AF in the specific stripe region SA1 is divided into the autofocus region AF in the adjacent stripe region SA2, and the adjacent stripe region SA2 included in the Y coordinate range equivalent to the Y coordinate range divided into the out-of-focus region NF in the specific stripe region SA1 is divided into the out-of-focus region NF in the adjacent stripe region SA2. In this way, for two or more related stripe regions SA, the autofocus region AF and the out-of-focus region NF in the other stripe region SA can be divided in correspondence with the division for one stripe region SA. In the following description, the same processing is performed, so the description is omitted.

[0077] The control unit 160 restricts the focusing process while scanning the out-of-focus area NF in the adjacent stripe area SA2 in the opposite direction to the scanning of the specific stripe area SA1 based on the movement trajectory of the out-of-focus area NF in the generated specific stripe area SA1. That is, the control unit 160 changes the position of the objective lens 131 with respect to the sample 80 in the optical axis direction of the objective lens 131 based on the movement trajectory, and restricts the focusing process from the position determined by the movement trajectory.

[0078] <Third Stripe> The control unit 160 may regard the third stripe region SA3 as having the same configuration as the specific stripe region SA1 and may perform scanning in the same manner as the specific stripe region SA1. If it is acceptable to add a movement to return the imaging position, scanning may be performed in a direction opposite to that of the specific stripe region SA1. This is because, when the second region 82 in the inspection region 85 extends in the X-axis direction, the third stripe region SA3 along the third stripe STR3 adjacent to the adjacent stripe STR2 in the X-axis direction can be regarded as having the same configuration as the specific stripe region SA1 and the adjacent stripe region SA2.

[0079] First, the control unit 160 divides the third stripe region SA3 along the third stripe STR3, which is not adjacent to the specific stripe STR1 and is adjacent to the adjacent stripe STR2, into an autofocus region AF and an out-of-focus region NF in correspondence with the division for the specific stripe region SA1.

[0080] Next, the control unit 160 generates a movement trajectory of the out-of-focus area NF in the adjacent striped region SA2 based on the focus information acquired in the adjacent striped region SA2, which is the focus information of two autofocus areas AF sandwiching the out-of-focus area NF in the adjacent striped region SA2. Then, the control unit 160 restricts the focusing process while scanning the out-of-focus area NF in the third striped region SA3 based on the movement trajectory generated for the adjacent striped region SA2. That is, the control unit 160 changes the position of the objective lens 131 with respect to the sample 80 in the optical axis direction of the objective lens 131 based on the movement trajectory, and restricts the focusing process from the position determined by the movement trajectory.

[0081] <Stripes other than specific stripes> 8 is a plan view illustrating a sample 80 in the inspection device 1 according to the first embodiment. As shown in FIG. 8, the control unit 160 may perform scanning of the stripe regions SA along the stripes STR other than the specific stripe STR1 in the same manner as the specific stripe region SA1, or may perform scanning in the opposite direction to that of the specific stripe region SA1. This is because, in the inspection region 85, when the second region 82 extends in the X-axis direction, the stripe regions SA along the stripes STR other than the specific stripe STR1 can be considered to have the same configuration as the specific stripe region SA1.

[0082] First, the control unit 160 divides the stripe areas SA other than the specific stripe area SA1 into an autofocus area AF and an out-of-focus area NF in correspondence with the division of the specific stripe area SA1.

[0083] Next, when the specific stripe STR1 is the i-th stripe STR, the control unit 160 scans the stripe region SA along the (i+2n)-th stripe STR in the same direction as the scanning of the specific stripe region SA1 in one direction. Also, the control unit 160 scans the stripe region SA along the (i+2n+1)-th stripe STR in the opposite direction to the scanning of the specific stripe region SA1 in one direction.

[0084] At the same time, the control unit 160 limits the focusing process while scanning the out-of-focus area NF in the (i+2n)th stripe area SA in the same direction as the scanning of the specific stripe area SA1 based on the movement trajectory of the out-of-focus area NF in the generated specific stripe area SA1.

[0085] Furthermore, the control unit 160 restricts the focusing process while scanning the out-of-focus region NF in the (i+2n+1)th stripe region SA in the opposite direction to the scanning of the specific stripe region SA1 based on the movement trajectory of the out-of-focus region NF in the generated specific stripe region SA1. That is, the control unit 160 changes the position of the objective lens 131 with respect to the sample 80 in the optical axis direction of the objective lens 131 based on the movement trajectory, and restricts the focusing process from the position determined by the trajectory.

[0086] <Testing method> Next, an inspection method using the inspection device 1 of this embodiment will be described. Fig. 9 and Fig. 10 are flow charts illustrating an inspection method using the inspection device 1 according to embodiment 1. As shown in Fig. 9, the inspection method of this embodiment includes a division step S11 and a scanning step S12. Also, as shown in Fig. 10, the inspection method of this embodiment further includes a focus information acquisition step S21 and a trajectory generation step S22.

[0087] In the division step S11, in an inspection area 85 including a plurality of stripe areas SA extending in one direction on a sample 80, the stripe areas SA are divided into autofocus areas AF and out-of-focus areas NF. In the division step S11, as described above, the division may be performed based on focus information or design data. The division may also be performed while processing data obtained during scanning. A method for dividing the stripe areas SA into autofocus areas AF and out-of-focus areas NF using focus information acquired by a pre-scan will be described below.

[0088] Fig. 11 is a flow chart illustrating an inspection method using the inspection apparatus 1 according to embodiment 1. As shown in Fig. 11, the inspection method further includes a pre-scan step S10 in addition to the flow of Fig. 9. The pre-scan step S10 corresponds to the case where focus information for the entire specific stripe region SA1 is acquired in the focus information acquisition step S21 shown in Fig. 10.

[0089] That is, in the prescan step S10, the imaging position scans the entire specific stripe region SA1 and performs focusing to obtain focus information for the entire specific stripe region SA1. Then, in the division step S11, based on the obtained focus information for the specific stripe region SA1, the specific stripe region is divided into an autofocus region AF and an out-of-focus region NF.

[0090] In addition, when dividing the stripe area SA into an autofocus area AF and an out-of-focus area NF based on design data, and when dividing the area while processing data during scanning, it is not necessary to use the pre-scan step S10, as shown in FIG. 9.

[0091] In the scanning step S12, when the imaging position of the sample 80 is scanned along the stripe region SA, in the autofocus region AF, a focusing process is performed by changing the relative position between the objective lens 131 and the sample 80 along the optical axis direction of the objective lens 131 based on the focus state information, and in the out-of-focus region NF, the focusing process is restricted and scanning is performed.

[0092] Here, the out-of-focus area NF is scanned with limited focusing, specifically, the out-of-focus area NF is scanned based on a moving trajectory without performing a focusing process. Therefore, as shown in Fig. 10, a moving trajectory is generated by a focus information acquisition step S21 and an activation generation step S22.

[0093] In the focus information acquisition step S21, the imaging position scans at least two autofocus areas AF sandwiching an out-of-focus area NF in the stripe area SA, and performs a focusing process to acquire focus information. In the focus information acquisition step S21, focus information of a specific stripe area SA1 among the multiple stripe areas SA may be acquired. Also, in addition to the autofocus area AF in the specific stripe area SA1, the out-of-focus area NF may also be subjected to a focusing process. In other words, the focusing process may be performed over the entire area of ​​the specific stripe area SA1.

[0094] The trajectory generating step S22 generates a movement trajectory of the out-of-focus area NF in the stripe area SA based on the focus information acquired in the focus information acquiring step S21. For example, the trajectory generating step S22 may generate the movement trajectory of the out-of-focus area NF in the stripe area SA by performing an interpolation data process on the focus information of the two autofocus areas AF that sandwich the out-of-focus area NF acquired in the focus information acquiring step S21. In this manner, a movement trajectory including the out-of-focus area NF is generated.

[0095] In the scanning step S12, the position of the objective lens 131 is moved in the optical axis direction of the objective lens 131 based on the movement trajectory generated in the trajectory generating step S13 in the out-of-focus region NF in the stripe region SA, and the focusing process is limited from the position determined by the movement trajectory. In this manner, the sample 80 can be inspected.

[0096] The division step S11 may divide the adjacent stripe region SA2 into an autofocus region AF and an out-of-focus region NF in correspondence with the division for the specific stripe region SA1. In that case, the scanning step S12 may limit the focusing process while scanning the out-of-focus region NF in the adjacent stripe region SA2 in a direction opposite to the scanning of the specific stripe region SA1 in one direction based on the movement trajectory of the out-of-focus region NF in the specific stripe region SA1 generated in the trajectory generating step S22. That is, based on the movement trajectory, the position of the objective lens 131 with respect to the sample 80 is changed in the optical axis direction of the objective lens 131, and the focusing process from the position determined by the movement trajectory is limited.

[0097] Also, the division step S11 may divide the third stripe region SA3 into an autofocus region AF and an out-of-focus region NF in correspondence with the division for the specific stripe region SA1. In that case, the trajectory generation step S22 generates a movement trajectory of the out-of-focus region NF in the adjacent stripe region SA2 based on the focus information acquired in the scanning step S12 for the adjacent stripe STR2, which is the focus information of the two autofocus regions AF sandwiching the out-of-focus region AF in the adjacent stripe region SA2. The scanning step S12 scans the out-of-focus region NF in the third stripe region SA3 in the same direction as the scanning of the specific stripe region SA1 in one direction based on the movement trajectory of the out-of-focus region NF in the adjacent stripe region SA2 generated in the trajectory generation step S22 for the adjacent stripe region SA2, while restricting the focusing process. That is, based on the movement trajectory, the position of the objective lens 131 with respect to the sample 80 is changed in the optical axis direction of the objective lens 131, and the focusing process from the position determined by the trajectory is restricted.

[0098] Furthermore, the division step S11 may divide the stripe regions SA other than the specific stripe region SA1 into an autofocus region AF and an out-of-focus region NF in correspondence with the division for the specific stripe region SA1. In that case, the scanning step S12 scans the stripe region SA along the (i+2n)th stripe STR in the same direction as the scanning of the specific stripe region SA1 in one direction, assuming that the specific stripe STR1 is the i-th stripe STR. The scanning step S12 scans the stripe region SA along the (i+2n+1)th stripe STR in the opposite direction to the scanning of the specific stripe region SA1 in one direction. In addition, the out-of-focus region NF in the (i+2n)th stripe region SA is scanned in the same direction as the scanning of the specific stripe region SA1 based on the movement trajectory of the out-of-focus region NF in the specific stripe region SA1 generated in the trajectory generation step S22, while limiting the focusing process. Also, the out-of-focus area NF in the (i+2n+1)th stripe area SA is scanned in the opposite direction to the scanning of the specific stripe area SA1 based on the movement trajectory of the out-of-focus area NF in the specific stripe area SA1 generated in the trajectory generating step S22, while limiting the focusing process. That is, based on the movement trajectory, the position of the objective lens 131 with respect to the sample 80 is changed in the optical axis direction of the objective lens 131, and the focusing process from the position determined by the trajectory is limited.

[0099] Next, the effect of this embodiment will be described. In this embodiment, in the autofocus area AF, focusing is performed based on focus information, and in the out-of-focus area NF, focusing is restricted and scanning is performed. Therefore, it is possible to suppress a sudden change in the position of the objective lens 131 at the boundary between the autofocus area AF and the out-of-focus area NF.

[0100] In contrast, when the out-of-focus area NF of the stripe area SA is moved randomly, a sudden change in the position of the objective lens 131 occurs at the boundary between the autofocus area AF and the out-of-focus area NF. When such a change occurs, it takes longer for the focus unit 150 to return the objective lens 131 to the focus position. In this embodiment, such a sudden change is suppressed, and therefore the throughput can be improved.

[0101] In addition, in this embodiment, focusing is limited in the out-of-focus area NF based on the generated movement trajectory. The movement trajectory is generated based on focus information in two autofocus areas AF that sandwich the out-of-focus area NF. Therefore, the movement trajectory and the autofocus area AF can be smoothly connected, and the throughput of the inspection can be improved.

[0102] In addition, in this embodiment, the imaging position in the stripe region SA is scanned alternately in the +Y-axis direction and the -Y-axis direction, which can minimize movement to adjacent stripe regions SA and improve the throughput of the inspection.

[0103] The out-of-focus area NF may include at least one of a black border, a scribe, a unique portion, etc. Since a movement trajectory can be generated for these out-of-focus areas NF as well, the connection between the movement trajectory and the autofocus area AF can be made smooth, and the throughput of the inspection can be improved.

[0104] (Embodiment 2) Next, an inspection device and an inspection method according to a second embodiment will be described. The inspection device and the inspection method according to this embodiment have a function of performing auxiliary autofocus. FIG. 12 is a configuration diagram illustrating an inspection device 2 according to the second embodiment. As shown in FIG. 12, the inspection device 2 further includes an auxiliary focus unit 170.

[0105] The auxiliary focusing unit 170 detects focus deviation caused by vibration of the sample 80. The auxiliary focusing unit 170 also outputs auxiliary focus information including the position of the objective lens 131 focused on the sample 80 to the control unit 160. The auxiliary focusing unit 170 also performs auxiliary focusing by moving the position of the objective lens 131 in the optical axis direction of the objective lens 131. In the figure, the auxiliary focusing unit 170 is shown in a simplified schematic configuration. However, the auxiliary focusing unit 170 may have the same configuration as the focusing unit 150 while being independent from the focusing unit 150. The function of the auxiliary focusing unit 170 may also be incorporated into the focusing unit 150.

[0106] At least in the autofocus area AF, the control unit 160 causes the auxiliary focus unit 170 to perform auxiliary focusing by moving the position of the objective lens 131 in the optical axis direction of the objective lens 131 based on the auxiliary focus information. The control unit 160 may also cause the auxiliary focus unit 170 to perform auxiliary focusing in the out-of-focus area NF.

[0107] The out-of-focus region NF may include at least one of a second region 82 such as a black border, a third region 83 such as a scribe, and a fourth region 84 such as a unique portion. The control unit 160 may cause the auxiliary focusing unit 170 to perform auxiliary focusing on at least one of the black border, the scribe, and the unique portion in the out-of-focus region NF based on the auxiliary focus information.

[0108] The frequency at which the objective lens 131 is moved in the optical axis direction of the objective lens 131 during auxiliary focusing is greater than the frequency at which the objective lens 131 is moved in the optical axis direction of the objective lens 131 during focusing.

[0109] In the inspection method of this embodiment, the scanning step S12 performs auxiliary focusing at least in the autofocus area AF by moving the position of the objective lens 131 in the optical axis direction of the objective lens 131 based on the auxiliary focus information.

[0110] According to this embodiment, since the focus deviation caused by the vibration of the sample 80 can be corrected, the inspection accuracy can be further improved. In addition, by scanning the movement trajectory in a portion where the focus state is different from the actual state, such as a singular point, a sudden change can be suppressed. Therefore, the throughput of the inspection can be improved.

[0111] (Embodiment 3) Next, a third embodiment will be described. The configuration of the inspection apparatus of this embodiment may be the configuration of the first embodiment or the second embodiment, or may include necessary configurations added to these configurations as appropriate. In this embodiment, the focusing process includes an auxiliary focusing process and a main focusing process. In the auxiliary focusing process, the amount of change in the relative position between the objective lens 131 and the sample 80 along the optical axis direction of the objective lens 31 is kept within a predetermined range caused by the vibration of the sample 80, that is, the amount of change in the relative position is limited within a predetermined range, and the focusing process is performed. In the main focusing process, the amount of change in the relative position between the objective lens 131 and the sample 80 along the optical axis direction of the objective lens 131 is not kept within a predetermined range caused by the vibration of the sample 80, that is, even if the amount of change in the relative position exceeds the predetermined range, the focusing process is performed. The control unit 160 restricts the focusing process from a position determined by the movement orbit by at least prohibiting the main focusing process in the out-of-focus area NF in the stripe area SA. In other words, the control unit 160 prohibits the auxiliary focusing process and prohibits the main focusing process, thereby not performing the focusing process from the position determined by the movement trajectory in the first place (restricting the focusing process), or allows the auxiliary focusing process and prohibits the main focusing process, thereby limiting the amount of change in the relative position between the objective lens 131 and the sample 80 along the optical axis direction of the objective lens 131 from the position determined by the movement trajectory to within a predetermined range caused by vibration of the sample 80, thereby restricting the focusing process.

[0112] The control unit 160 first determines the type of the out-of-focus area NF. The control unit 160 determines the type of the out-of-focus area NF based on, for example, the design data of the sample 80, based on the focus information being a predetermined value or a change in value, or based on both. Then, when the type of the out-of-focus area NF in the stripe area SA is a predetermined first type, the control unit 160 prohibits the auxiliary focusing process and prohibits the main focusing process, thereby restricting the focusing process from the position determined by the movement trajectory. On the other hand, when the type of the out-of-focus area NF in the stripe area SA is not the first type, the control unit 160 allows the auxiliary focusing process and prohibits the main focusing process, thereby restricting the focusing process from the position determined by the movement trajectory. This makes it possible to restrict the focusing process according to the type of the out-of-focus area NF.

[0113] Here, the control unit 160 determines the type of the out-of-focus area NF as follows. That is, the control unit 160 may determine the black border as the first type and the scribe as the second type as the type of the out-of-focus area NF. The control unit 160 may also determine the black border as the first type and the unique portion as the second type as the type of the out-of-focus area NF. The control unit 160 may also determine the black border as the first type and the scribe and unique portion as the second type as the type of the out-of-focus area NF.

[0114] Furthermore, the control unit 160 may determine the type of the out-of-focus area NF as a first type, the scribe as a second type, and the unique portion as a third type. Furthermore, the control unit 160 may determine the type of the out-of-focus area NF as a first type, the black border and the scribe as a first type, and the unique portion as a second type. Furthermore, the control unit 160 may determine the type of the out-of-focus area NF as a first type, the black border and the unique portion as a first type, and the scribe as a second type.

[0115] In this way, when the out-of-focus area NF includes a black border and a scribe, the control unit 160 determines the black border to be of the first type and the scribe to be of a predetermined type different from the first type. When the out-of-focus area NF includes a black border and a unique portion, the control unit 160 determines the black border to be of the first type and the unique portion to be of a predetermined type different from the first type. When the out-of-focus area NF includes a black border, a scribe, and a unique portion, the control unit 160 determines the black border to be of the first type and determines at least one of the scribe and the unique portion to be of a predetermined type different from the first type.

[0116] In the inspection method of this embodiment, the scanning step S12 restricts the focusing process from a position determined by the movement track by prohibiting at least the main focusing process in the out-of-focus area NF in the stripe area SA. The inspection method of this embodiment may also include a determination step of determining the type of the out-of-focus area NF. In that case, the scanning step S12 restricts the focusing process from a position determined by the movement track by prohibiting the auxiliary focusing process and the main focusing process when the type of the out-of-focus area NF in the stripe area SA is a predetermined first type. When the type of the out-of-focus area is not the first type, the scanning step S12 permits the auxiliary focusing process and prohibits the main focusing process, thereby restricting the focusing process from a position determined by the movement track. Furthermore, the focusing process is restricted according to the types of the black border, scribe, and unique part included in the out-of-focus area NF.

[0117] According to this embodiment, it is possible to further improve the inspection accuracy since it is possible to correct the focus deviation caused by factors other than the vibration of the sample 80. Also, since the focusing process is limited according to the type of the out-of-focus area NF such as a black border, a scribe, and a unique part, it is possible to improve the inspection throughput.

[0118] (Embodiment 4) An inspection device and an inspection method according to the fourth embodiment will be described with reference to the drawings. FIGS. 13 and 14 are configuration diagrams illustrating an inspection device according to the fourth embodiment. As shown in FIG. 13, the inspection device 4 according to this embodiment includes a stage 10, an illumination optical system 20, an imaging unit 30, a scanning unit 40, a focusing unit 50, and a control unit 60. For example, the inspection device 1 is a transmission type inspection device that detects defects present in a sample 80 such as a photomask by transmitted light. As shown in FIG. 14, the inspection device 4a may be a reflection type inspection device that detects defects using reflected light from the sample 80, and an inspection device that detects defects based on a composite image in which a transmission image and a reflection image are combined.

[0119] The configurations of the stage 10 and the scanning unit 40 are similar to the configurations of the stage 110 and the scanning unit 140 in the first to third embodiments.

[0120] The illumination optical system 20 illuminates the sample 80 with illumination light L1. In Figs. 13 and 14, only the optical axis of the illumination light L1 is shown. The illumination optical system 20 includes an illumination light source 21, a mirror 22, and a condenser lens 23. In the inspection device 4a, the objective lens 31 also serves as the condenser lens 23. The illumination optical system 20 may include optical members other than those described above. The illumination light source 21 generates illumination light L1 for inspection. The illumination light L1 emitted from the illumination light source 21 is reflected by the mirror 22, and is collected by the condenser lens 23 and enters the sample 80. The transmitted light L2 transmitted through the sample 80 enters the objective lens 31 in the imaging unit 30. As shown in Fig. 14, when the inspection device 4a is a reflection type, the reflected light L2a reflected by the sample 80 enters the objective lens 31.

[0121] <Imaging unit> The imaging unit 30 captures an image of the sample 80. The imaging unit 30 includes an objective lens 31, a half mirror 32, a mirror 33, a lens 34, an image sensor 35, an amplifier 36, and a signal processing device 37. The imaging unit 30 may include other components than those described above. The objective lens 31 faces the sample 80. The objective lens 31 collects transmitted light L2 or reflected light L2a from the sample 80 illuminated with illumination light L1. The transmitted light L2 or reflected light L2a transmitted through the objective lens 31 passes through the half mirror 32 and is reflected by the mirror 33. The transmitted light L2 or reflected light L2a is then collected by the lens 34 and imaged by the image sensor 35.

[0122] The configurations of the image pickup element 35, the amplifier 36, and the signal processing device 37 are similar to the configurations of the image pickup element 135, the amplifier 136, and the signal processing device 137 in the first to third embodiments.

[0123] <Focus section> The focusing unit 50 detects the focus state of the objective lens 31. The focusing unit 50 outputs focus state information including the detected focus state of the objective lens 31 to the control unit 60. The focusing unit 50 also outputs focus information including position information of the objective lens 31 focused on the sample 80 to the control unit 60. The focusing unit 50 performs a focusing process to adjust the focus of the objective lens 31 by changing the relative position of the objective lens 31 and the sample 80 along the optical axis direction of the objective lens 31. The objective lens 31 is supported so as to be movable along its optical axis direction. Instead of the objective lens 31 being supported so as to be movable along its optical axis direction, the stage 10 holding the sample 80 may be made movable along the optical axis direction of the objective lens 31. In this case, the driving unit 55 of the focusing unit 50 moves the stage 10. The focusing unit 50 has a light source 51, a mirror 52, a photodetector 53, a processing device 54, a driving unit 55, and a position sensor 56.

[0124] The light source 51 emits a light beam L3. The light beam L3 emitted from the light source 51 is reflected by the half mirror 32 and enters the sample 80 via the objective lens 31. The reflected beam L4 reflected by the upper surface of the sample 80 passes through the objective lens 31, is reflected by the half mirror 32 and the mirror 52, and enters the photodetector 53. Then, a light spot is formed on the photodetector 53. The photodetector 53 acts as a focus detector that detects the focus state of the objective lens 31 with respect to the upper surface of the sample 80.

[0125] As the focus detector, various types of focus detectors may be used. Also, the photodetector 53 may be configured as a line sensor having a plurality of light receiving elements arranged in the moving direction of the light spot. In this embodiment, as the focus detector, a two-split type photodetector 53 having two photodiodes 53a and 53b and a split line 53c is used.

[0126] 15 to 17 are diagrams illustrating the movement of the light spot L5 formed on the photodetector 53 in the inspection device 4 according to the fourth embodiment. The reflected beam L4 incident on the photodetector 53 forms a substantially circular light spot L5 on the photodetector 53 as shown in FIG. 15. The light spot L5 moves in one direction according to the focus error. Therefore, the two photodiodes 53a and 53b are arranged along the movement direction of the light spot L5. The output signals Ia and Ib from the two photodiodes 53a and 53b of the photodetector 53 are used as focus error signals indicating the amount of displacement in the optical axis direction between the focus of the objective lens 31 and the upper surface of the sample 80, and are supplied to the processing device 54.

[0127] For example, when the upper surface of the sample 80 is displaced in the optical axis direction due to bending or the like formed in the sample 80, the incident point of the autofocus light beam L3 on the sample 80 also displaces. In accordance with this displacement, the light spot L5 formed on the photodetector 53 displaces in one direction.

[0128] When the focal point of the objective lens 31 is located on the upper surface of the sample 80, that is, when the objective lens 31 is focused on the upper surface of the sample 80, the center of the light spot L5 is located on the division line 53c, as shown in Fig. 15. In this case, the intensities of the output signals Ia and Ib output from the photodiodes 53a and 53b are equal to each other. The difference between the output signals Ia and Ib is zero.

[0129] On the other hand, when the top surface of the sample 80 is displaced in the optical axis direction or the objective lens 31 is displaced in the optical axis direction, the incident point of the autofocus light beam L3 on the sample 80 is displaced. In accordance with this displacement, the light spot L5 formed on the photodetector 53 is also displaced.

[0130] When the focus of the objective lens 31 is displaced above the top surface of the sample 80, the center of the light spot L5 moves toward the photodiode 53a as shown in Fig. 16. This increases the intensity of the output signal from the photodiode 53a, and decreases the intensity of the output signal from the photodiode 53b. When the focus of the objective lens 31 is displaced below the top surface of the sample 80, the center of the light spot L5 moves toward the photodiode 53b as shown in Fig. 17. This decreases the intensity of the output signal from the photodiode 53a, and increases the intensity of the output signal from the photodiode 53b.

[0131] Therefore, by detecting the difference in intensity between the output signals of the two photodiodes 53a and 53b, it is possible to detect the amount of misalignment in the optical axis direction between the focal point of the objective lens 31 and the upper surface of the sample 80. In this embodiment, the two-part photodiodes 53a and 53b are used as the photodetector 53, but it is also possible to configure it as a line sensor having a plurality of light receiving elements arranged in the displacement direction of the light spot L5.

[0132] The driving unit 55 is attached to the objective lens 31. The driving unit 55 includes a member having a driving function, such as an actuator. Specifically, the driving unit 55 may use an actuator including a piezoelectric element. The amount of displacement of the objective lens 31 in the optical axis direction is controlled by a driving voltage signal applied to the piezoelectric element. In this way, the driving unit 55 moves the position of the objective lens 31 along the optical axis direction. The driving unit 55 may be attached to a stage 10 that holds a sample 80. The driving unit 55 may then move the stage 10 along the optical axis direction of the objective lens 31. In this way, the driving unit 55 can change the relative positions of the objective lens 31 and the sample 80.

[0133] The position sensor 56 is attached to the objective lens 31. The position sensor 56 detects the position of the objective lens 31 in the optical axis direction. In this embodiment, the position sensor 56 uses, for example, a combination of a Z-axis scale and a linear encoder. The position sensor 56 detects the height of the objective lens 31 in the optical axis direction by using an output signal from the linear encoder. The control unit 60 acquires the relative position between the objective lens 31 and the sample 80 based on the position information output from at least one of the position sensor 56 and the position sensor 41.

[0134] <Control Unit> The control unit 60 controls the stage 10, the illumination optical system 20, the imaging unit 30, the scanning unit 40, and the focusing unit 50. The configuration and operation of the control unit 60 are similar to the configuration and operation of the control unit 160 in the first to third embodiments.

[0135] Although the embodiments of the present disclosure have been described above, the present disclosure includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-mentioned embodiments. In addition, combinations of the configurations of the first to fourth embodiments are also within the scope of the technical idea of ​​the present disclosure. [Explanation of symbols]

[0136] 1, 2, 4, 4a Inspection equipment 10 Stages 20 Illumination optical system 21 Lighting source 22. Mirror 23 Condenser Lens 30 Imaging unit 31 Objective Lens 32 Half Mirror 33 Mirror 34 Lens 35 Image sensor 36 Amplifier 37 Signal Processing Device 40 Scanning unit 41 Position Sensor 50 Focus section 51 Light source 52 Mirror 53 Photodetector 53a, 53b Photodiode 53c dividing line 54 Processing equipment 55 Drive unit 56 Position Sensor 60 Control section 80 samples 81 First area 82 Second area 83 Third area 84 4th area 85 Inspection Area 110 Stages 120 Illumination optical system 121 Lighting source 122 Field Aperture 122a CAF Slit 122b, 122c Slit 123 Non-polarizing beam splitter 130 Imaging unit 131 Objective Lens 132 Mirror 133 Half Mirror 134 Lens 135 Image sensor 136 Amplifier 137 Signal Processing Device 140 Scanning unit 141 Position Sensor 150 Focus section 151 Half Mirror 152, 153 Light receiving section 154 Processing equipment 155 Drive unit 156 Position Sensor 160 Control section 170 Auxiliary focus unit B101, B102, B103 Beam L1, L101 illumination light L2 transmitted light L2a reflected light L3 Light Beam L4 Reflected Beam L5 Light Spot R101 Reflected light SA stripe area SA1 Specific stripe area SA2 adjacent stripe area SA3 Third stripe area STR Stripe STR1 Specific Stripe STR2 Adjacency and Life STR3 3rd Stripe

Claims

1. A dividing step of dividing an inspection area including a plurality of stripe areas extending in one direction on a sample into an autofocus area and an out-of-focus area; a scanning step of performing a focusing process in the autofocus region to adjust the focus by changing the relative position between the objective lens and the sample along the optical axis direction of the objective lens based on focus state information output from a focusing unit that detects the focus state of the objective lens when an imaging position of the sample imaged by an imaging unit including an objective lens facing the sample is scanned along the stripe region, and performing scanning while restricting the focusing process in the out-of-focus region; An inspection method comprising: a focus information acquisition step of acquiring focus information including position information of the objective lens focusing on the sample by scanning the imaging position through at least two of the autofocus regions sandwiching the out-of-focus region in a specific stripe region among the plurality of stripe regions and performing the focusing process; a trajectory generating step of generating a movement trajectory of the out-of-focus region in the specific stripe region based on the focus information acquired in the focus information acquiring step; Further equipped with In the scanning step, in the out-of-focus region of the stripe region, a position of the objective lens is changed in an optical axis direction of the objective lens based on the movement trajectory generated in the trajectory generating step, and the focusing process is limited from a position determined by the movement trajectory. Testing method.

2. The focus information acquisition step includes: The imaging position scans the specific stripe region, and the focusing process is performed to obtain the focus information of the specific stripe region; The dividing step includes: dividing the specific stripe region into the autofocus region and the out-of-focus region based on the focus information of the specific stripe region acquired in the focus information acquisition step; The inspection method according to claim 1 .

3. The trajectory generating step includes: generating the movement trajectory of the out-of-focus area in the specific stripe area by performing an interpolation data process on the focus information of the two autofocus areas sandwiching the out-of-focus area acquired in the focus information acquisition step; The inspection method according to claim 1 .

4. The dividing step includes: Dividing an adjacent stripe region along an adjacent stripe adjacent to a specific stripe into the autofocus region and the out-of-focus region in correspondence with a division of the specific stripe region; The scanning step includes: limiting the focusing process while scanning the out-of-focus area in the adjacent stripe area in a direction opposite to the scanning of the specific stripe area in the one direction based on the movement trajectory of the out-of-focus area in the specific stripe area generated in the trajectory generating step; The inspection method according to claim 1 .

5. The dividing step includes: A third stripe region along a third stripe that is not adjacent to the specific stripe and is adjacent to the adjacent stripe is divided into the autofocus region and the out-of-focus region in correspondence with the division of the specific stripe region; The trajectory generating step includes: generating the movement trajectory of the out-of-focus region in the adjacent stripe region based on the focus information acquired in the scanning step for the adjacent stripe region, the focus information being on two of the autofocus regions sandwiching the out-of-focus region in the adjacent stripe region; The scanning step includes: limiting the focusing process while scanning the out-of-focus area in the third stripe area based on the movement trajectory generated for the adjacent stripe; The inspection method according to claim 4.

6. The dividing step includes: Dividing the stripe region other than the specific stripe region into the autofocus region and the out-of-focus region corresponding to the division of the specific stripe region; The scanning step includes: When the specific stripe is an i-th stripe, the stripe region along the (i+2n)-th stripe is scanned in the same direction as the scanning of the specific stripe region in the one direction, and the stripe region along the (i+2n+1)-th stripe is scanned in a direction opposite to the scanning of the specific stripe region in the one direction, and, limiting the focusing process while scanning the out-of-focus area in the (i+2n)th stripe area in the same direction based on the movement trajectory of the out-of-focus area in the specific stripe area generated in the trajectory generating step; limiting the focusing process while scanning the out-of-focus area in the (i+2n+1)th stripe area in the reverse direction based on the movement trajectory of the out-of-focus area in the specific stripe area generated in the trajectory generating step; The inspection method according to claim 1 .

7. The focus information includes a luminance at the imaging position focused on the sample. The inspection method according to claim 1 .

8. The focusing process includes: an auxiliary focusing process for confining a change in a relative position between the objective lens and the sample along an optical axis direction of the objective lens within a predetermined range caused by vibration of the sample, and a main focusing process for not confining the change within the predetermined range, the scanning step restricts the focusing process from a position determined by the movement trajectory by prohibiting at least the main focusing process in the out-of-focus region of the stripe region. The inspection method according to claim 1 .

9. A determination step of determining a type of the out-of-focus area, The scanning step includes, in the out-of-focus region of the stripe region, When the type of the out-of-focus area is a predetermined first type, the auxiliary focusing process is prohibited, and the main focusing process is prohibited, thereby restricting the focusing process from a position determined by the movement trajectory; if the type of the out-of-focus area is not the first type, the auxiliary focusing process is permitted and the main focusing process is prohibited, thereby restricting the focusing process from a position determined by the movement trajectory. The inspection method according to claim 8.

10. The determining step includes: When the out-of-focus region includes a groove-shaped black border surrounding a plurality of dies formed on the sample, and a scribe between the dies formed on the sample, the black border is determined to be the first type, and the scribe is determined to be a predetermined type different from the first type; When the out-of-focus region includes the black border and a unique portion formed on the sample and exhibiting a change in position that is greater than a change in actual position, the black border is determined to be of the first type, and the unique portion is determined to be of the predetermined type that is different from the first type; When the out-of-focus area includes the black border, the scribe, and the unique portion, the black border is determined to be the first type, and at least one of the scribe and the unique portion is determined to be the predetermined type different from the first type. The inspection method according to claim 9.

11. an imaging unit including an objective lens facing a sample, the imaging unit imaging the sample; a scanning unit that scans an imaging position of the sample to be imaged by the imaging unit; a focusing unit that detects a focus state of the objective lens, outputs detected focus state information, and outputs focus information including position information of the objective lens focused on the sample, the focusing unit performing a focusing process to adjust the focus by changing a relative position between the objective lens and the sample along an optical axis direction of the objective lens; A control unit that controls the imaging unit, the scanning unit, and the focusing unit; Equipped with The control unit is In an inspection area including a plurality of stripe regions extending in one direction on the sample, the stripe regions are divided into an autofocus area and an out-of-focus area; when the imaging unit scans the imaging position of the sample to be imaged along the stripe region, in the autofocus region, the focus unit performs the focusing process by changing the relative position in the optical axis direction of the objective lens based on the focus state information, and in the out-of-focus region, the scanning unit scans while restricting the focusing process; The imaging position scans at least two of the autofocus regions sandwiching the out-of-focus region in a specific stripe region among the plurality of stripe regions, and performs the focusing process to acquire the focus information; generating a movement trajectory of the out-of-focus area in the specific stripe area based on the acquired focus information; In the out-of-focus region of the stripe region, a position of the objective lens is changed in an optical axis direction of the objective lens based on the generated movement trajectory, and the focusing process is limited from a position determined by the movement trajectory. Inspection equipment.

12. The control unit is The specific stripe region is scanned at the imaging position, and the focusing process is performed to obtain the focus information of the specific stripe region; Dividing the specific stripe region into the autofocus region and the out-of-focus region based on the focus information of the specific stripe region; The inspection apparatus according to claim 11.

13. The control unit is generating the movement trajectory of the out-of-focus area in the specific stripe area by performing an interpolation data process on the focus information of the two autofocus areas sandwiching the acquired out-of-focus area; The inspection apparatus according to claim 11.

14. The control unit is Dividing an adjacent stripe region along an adjacent stripe adjacent to a specific stripe into the autofocus region and the out-of-focus region in correspondence with a division of the specific stripe region; limiting the focusing process while scanning the out-of-focus area in the adjacent stripe area in a direction opposite to the scanning of the specific stripe area in the one direction based on the generated movement trajectory of the out-of-focus area in the specific stripe area; The inspection apparatus according to claim 11.

15. The control unit is A third stripe region along a third stripe that is not adjacent to the specific stripe and is adjacent to the adjacent stripe is divided into the autofocus region and the out-of-focus region in correspondence with the division of the specific stripe region; generating the movement trajectory of the out-of-focus region in the adjacent stripe region based on the focus information acquired in the adjacent stripe region, the focus information being of two autofocus regions sandwiching the out-of-focus region in the adjacent stripe region; limiting the focusing process while scanning the out-of-focus area in the third stripe area based on the movement trajectory generated for the adjacent stripe area; 15. The inspection apparatus according to claim 14.

16. The control unit is Dividing the stripe region other than the specific stripe region into the autofocus region and the out-of-focus region corresponding to the division of the specific stripe region; When the specific stripe is an i-th stripe, the stripe region along the (i+2n)-th stripe is scanned in the same direction as the scanning of the specific stripe region in the one direction, and the stripe region along the (i+2n+1)-th stripe is scanned in a direction opposite to the scanning of the specific stripe region in the one direction, and, limiting the focusing process while scanning the out-of-focus area in the (i+2n)th stripe area in the same direction based on the movement trajectory of the out-of-focus area in the generated specific stripe area; limiting the focusing process while scanning the out-of-focus area in the (i+2n+1)th stripe area in the reverse direction based on the movement trajectory of the out-of-focus area in the generated specific stripe area; The inspection apparatus according to claim 11.

17. The focus information includes a luminance at the imaging position focused on the sample. The inspection apparatus according to claim 11.

18. The focusing process includes: an auxiliary focusing process for confining a change in a relative position between the objective lens and the sample along an optical axis direction of the objective lens within a predetermined range caused by vibration of the sample, and a main focusing process for not confining the change within the predetermined range, the control unit prohibits at least the main focusing process in the out-of-focus region in the stripe region, thereby restricting the focusing process from a position determined by the movement trajectory. The inspection apparatus according to claim 11.

19. The control unit is determining a type of the out-of-focus area; In the out-of-focus region of the stripe region, When the type of the out-of-focus area is a predetermined first type, the auxiliary focusing process is prohibited, and the main focusing process is prohibited, thereby restricting the focusing process from a position determined by the movement trajectory; if the type of the out-of-focus area is not the first type, the auxiliary focusing process is permitted and the main focusing process is prohibited, thereby restricting the focusing process from a position determined by the movement trajectory.

20. The inspection apparatus of claim 18.

20. When the out-of-focus region includes a groove-shaped black border surrounding a plurality of dies formed on the sample, and a scribe between the dies formed on the sample, the control unit determines the black border to be the first type and determines the scribe to be a predetermined type different from the first type, When the out-of-focus region includes the black border and a unique portion formed on the sample and exhibiting a change in position larger than a change in actual position, the control unit determines the black border to be the first type and determines the unique portion to be the predetermined type different from the first type, When the out-of-focus area includes the black border, the scribe, and the unique portion, the control unit determines the black border to be the first type, and determines at least one of the scribe and the unique portion to be the predetermined type different from the first type.

20. The inspection apparatus of claim 19.

Images