Appearance inspection device and method for controlling appearance inspection device

Abstract

Provided is an appearance inspection device capable of adsorbing and fixing a wafer to a table even when the wafer is warped.　Specifically, this appearance inspection device 100 includes: a table 30 for adsorbing a semiconductor wafer W on a mounting surface of the semiconductor wafer W for mounting the semiconductor wafer W and fixing the semiconductor wafer W; and an air blowing part 40 for blowing compressed air onto the semiconductor wafer W. The air blowing part 40 can change a position relative to the table 30, and is configured to blow compressed air so as to press the semiconductor wafer W mounted on the surface of the table 30 against the surface of the table 30 in order to assist in fixing the wafer to the table when the semiconductor wafer W is adsorbed on the mounting surface.

Description

Visual inspection device and visual inspection device control method

[0001] The present invention relates to an appearance inspection apparatus and a control method for the appearance inspection apparatus, and more particularly to an appearance inspection apparatus and a control method for the appearance inspection apparatus for detecting defects on a wafer based on an appearance image.

[0002] 2. Description of the Related Art Conventionally, there has been known an appearance inspection apparatus for detecting defects in a wafer based on an appearance image (see, for example, Japanese Patent Application Laid-Open No. 2003-144998).

[0003] The above-mentioned Patent Document 1 discloses a defect inspection device that inspects the presence or absence of defects on a wafer based on an image of the wafer as an object. In the defect inspection device of the above-mentioned Patent Document 1, the wafer is placed on a table on a stage configured by a combination of an XY stage, a Z stage, etc., and the stage is moved so that repeating pattern portions on a chip can be imaged using a camera.

[0004] JP 2011-149869 A

[0005] Although not explicitly stated in Patent Document 1, in order to move the stage while the wafer is still on the table, the wafer mounting surface on the table is provided with, for example, a negative pressure suction means that generates a suction force to secure the wafer to the table. However, as wafers become thinner, flat-ground thin wafers can develop significant warpage when subjected to processing such as plating. For this reason, when attempting to secure a wafer with a large degree of warpage to the table, it may be impossible to secure the wafer by suction to the table due to a gap between the wafer mounting surface of the table and the wafer. Therefore, there is a need for an appearance inspection device and an appearance inspection method that can secure a wafer by suction to the table even when the wafer is warped.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an appearance inspection apparatus and an appearance inspection method that are capable of adsorbing and fixing a wafer to a table even if the wafer is warped.

[0007] In order to achieve the above object, the appearance inspection device according to this first aspect comprises an imaging unit that captures an appearance image of the wafer, a table that adsorbs the wafer on the wafer placement surface in order to place and fix the wafer, a defect detection unit that detects defects in the wafer based on the appearance image, and an air blowing unit that blows air onto the wafer, the air blowing unit being capable of changing its position relative to the table and being configured to blow air at the wafer placed on the surface of the table to press it against the surface of the table in order to assist in fixing the wafer to the table when adsorbing the wafer on the placement surface.

[0008] As described above, the visual inspection apparatus according to the first aspect is configured to blow air onto the wafer placed on the table surface to press the wafer against the table surface when the wafer is vacuum-sucked on the mounting surface, in order to assist in securing the wafer to the table. Thus, even if the wafer is warped and cannot be vacuum-sucked onto the surface of the vacuum-sucking table, the air blown onto the table surface to press the wafer corrects the warpage. This prevents a gap from forming between the table and the wafer, and allows the wafer to be vacuum-sucked and secured to the stage even if the wafer is warped. Here, because the state of warpage varies depending on the wafer processing step, it may be difficult to vacuum-suck and secure the wafer to the table simply by blowing air from a fixed position. Therefore, in the visual inspection apparatus according to the first aspect, the air blowing unit is configured to be positionally adjustable relative to the table, thereby enabling adaptation to various states of wafer warpage.

[0009] In the visual inspection apparatus according to the first aspect, the air blowing unit is preferably configured to include a compressed air blowing unit that blows compressed air as the air. With this configuration, even if the wafer has a large warp, the blowing of compressed air can press the wafer onto the surface of the table with a stronger force than blowing uncompressed air. As a result, even if the wafer has a relatively large warp, the wafer can be appropriately adsorbed and fixed to the stage.

[0010] The visual inspection apparatus according to the first aspect preferably further includes an elevating mechanism for moving the air blowing unit in the vertical direction so as to change its position relative to the table. With this configuration, by moving the air blowing unit in the upward direction, air can be blown over a wide area of ​​the wafer. As a result, when a relatively small amount of warpage occurs overall, the wafer can be properly corrected and the wafer can be vacuum-fixed to the stage. Furthermore, by moving the air blowing unit in the downward direction, air can be blown strongly onto a portion of the wafer. As a result, when a relatively large amount of warpage occurs in a portion of the wafer, the wafer can be properly corrected and the wafer can be vacuum-fixed to the stage. As a result, by changing the air blowing method depending on the state of the wafer warpage, it is possible to correct various types of wafer warpage, and therefore the wafer can be properly vacuum-fixed to the stage.

[0011] In the visual inspection apparatus according to the first aspect, the air blowing unit is preferably configured so that its position relative to the table can be changed, and at least one of the air blowing pressure and the air blowing time can be changed. With this configuration, the air blowing pressure or the air blowing time can be changed in addition to the relative position between the air blowing unit and the table, depending on the state of wafer warpage. As a result, by blowing air onto the wafer in accordance with the state of wafer warpage, it is possible to correct the warpage in accordance with the state of wafer warpage, which varies depending on the type of wafer processing and cannot be addressed by simply changing the air blowing position, and therefore the wafer can be more appropriately adsorbed and fixed to the stage.

[0012] The visual inspection apparatus according to the first aspect preferably further comprises a negative pressure measuring unit that measures negative pressure as the suction force of the wafer to the table when the table suctions the wafer, and a blowing control unit that controls the air blowing unit to blow air when the magnitude of the negative pressure measured by the negative pressure measuring unit does not exceed a predetermined threshold value. With this configuration, air can be blown appropriately only when the wafer is not sufficiently suctioned to the table, and therefore air blowing can be prevented even when air blowing is not necessary.

[0013] The visual inspection apparatus according to the first aspect is preferably configured to further include a horizontal movement mechanism for moving the air blowing unit in the horizontal direction so as to change the position of the air blowing unit relative to the table. With this configuration, air can be blown onto the wafer at any position in the horizontal direction depending on the state of warpage of the wafer, so that the wafer can be appropriately adsorbed and fixed to the table.

[0014] In this case, the air blowing unit is preferably configured to be movable horizontally by a horizontal movement mechanism while blowing air, which allows the change of the blowing position and the blowing of air to be performed simultaneously, thereby efficiently correcting the warpage of the wafer and efficiently shortening the time required for the process of sucking and fixing the wafer to the table.

[0015] In this case, the air blowing unit is preferably configured to blow air onto the wafer placed on the surface of the table while moving the air blowing unit horizontally along a predetermined trajectory using a horizontal movement mechanism. With this configuration, air can be appropriately blown onto the wafer by setting the trajectory according to the state of warpage of the wafer, which differs depending on the type of wafer processing.

[0016] In the visual inspection apparatus according to the first aspect, preferably, a plurality of air blowing units are provided, and the plurality of air blowing units are configured to blow air to different locations on the wafer placed on the surface of the table. With this configuration, even if it is difficult to correct the warpage of the wafer by blowing air from only one location depending on the state of the warpage of the wafer, it is possible to deal with various types of warpage of the wafer by blowing air to multiple locations on the wafer using the plurality of air blowing units.

[0017] The control method for an appearance inspection device according to this second aspect includes the steps of placing a wafer, sucking the wafer to fix it to the mounting surface, blowing air onto the wafer so as to press it against the mounting surface when sucking the wafer to assist in fixing the wafer to the mounting surface, and changing the position at which the air is blown onto the wafer.

[0018] As described above, the control method for a visual inspection apparatus according to the second aspect includes a step of blowing air onto the wafer mounting surface when sucking the wafer to assist in fixing the wafer to the mounting surface. As a result, even if the wafer is warped, the air blown onto the wafer mounting surface corrects the warpage, eliminating any gap between the table and the wafer. Therefore, even if the wafer is warped, the wafer can be sucked and fixed to the table. Here, because the state of warpage varies depending on the wafer processing step, it may be difficult to suck and fix the wafer to the table simply by blowing air from a fixed position. Therefore, by changing the position from which air is blown onto the wafer, a control method for a visual inspection apparatus can be provided that can accommodate various states of wafer warpage.

[0019] According to the present invention, as described above, it is possible to provide an appearance inspection apparatus and a method for controlling an appearance inspection apparatus that are capable of fixing a wafer to a table by suction even when the wafer is warped.

[0020] 1 is a schematic diagram showing a visual inspection apparatus according to a first embodiment; FIG. 2 is a block diagram for explaining the configuration of control by a control unit according to the first embodiment; FIG. 3 is a diagram for explaining a method of fixing a semiconductor wafer to a table according to the first embodiment; FIG. 4 is a diagram for explaining the state of warpage of a semiconductor wafer according to the first embodiment; (a) A diagram of upwardly convex warpage of a semiconductor wafer; (b) A diagram of upwardly concave warpage of a semiconductor wafer; FIG. 5 is a diagram for explaining the state of actual warpage of a semiconductor wafer according to the first embodiment; (a) A diagram of upwardly convex warpage of a semiconductor wafer; (b) A diagram of upwardly concave warpage of a semiconductor wafer; FIG. 6 is a diagram for explaining the state of actual warpage of a semiconductor wafer according to the first embodiment; (b) A diagram for explaining the transport of a semiconductor wafer onto lift pins by a robot arm according to the first embodiment; (c) A diagram for explaining the placement of a semiconductor wafer on lift pins according to the first embodiment; (d) A diagram for explaining the placement of a semiconductor wafer on a table according to the first embodiment; (e) A diagram for explaining the blowing of compressed air to a semiconductor wafer according to the first embodiment; (f) A diagram for explaining the blowing of compressed air to a semiconductor wafer when an air blowing unit is raised according to the first embodiment; (g) A diagram for explaining the blowing of compressed air to a semiconductor wafer when an air blowing unit is lowered according to the first embodiment. 1 is a flowchart for explaining the placement of a semiconductor wafer on a table according to a first embodiment. FIG. 2 is a block diagram for explaining the configuration of control by a control unit according to a second embodiment. FIG. 3 is a diagram for explaining the blowing of compressed air to a semiconductor wafer before moving an air blowing unit in a horizontal direction according to a second embodiment. FIG. 4 is a diagram for explaining the blowing of compressed air to a semiconductor wafer after moving an air blowing unit in a horizontal direction according to a second embodiment. FIG. 5 is a plan view for explaining a predetermined trajectory according to a second embodiment. FIG. 6 is a diagram at the start of air blowing when an air blowing unit blows air to a semiconductor wafer along a predetermined trajectory according to a second embodiment. FIG. 7 is a diagram at the completion of air blowing when an air blowing unit blows air to a semiconductor wafer along a predetermined trajectory according to a third embodiment. FIG. 8 is a diagram showing a visual inspection apparatus equipped with a plurality of air blowing units according to a third embodiment. FIG. 9 is a diagram showing a visual inspection apparatus according to a modified example in which five air blowing units are arranged in a cross shape. FIG. 10 is a perspective view of a visual inspection apparatus of a modified example.10B is a plan view showing the arrangement of the air blowing unit of the appearance inspection device of the modified example. FIG.

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] First Embodiment The configuration of a visual inspection apparatus 100 according to a first embodiment will be described with reference to FIG.

[0023] (Configuration of Visual Inspection Apparatus) As shown in Fig. 1, in the visual inspection apparatus 100, a table 30 on which a semiconductor wafer W is placed is moved horizontally (X direction and Y direction in Fig. 1) by a stage 10, and an image of the semiconductor wafer W is captured by an imaging unit 20 disposed above the stage 10 (Z1 side in Fig. 1). Then, based on the captured image, a defect detection unit 50 detects defects in the semiconductor wafer W. In Fig. 1, in order to capture an image of the semiconductor wafer W, the table 30 on which the semiconductor wafer W is placed is moved in the X1 direction by the stage 10, and is positioned below the imaging unit 20 (Z2 direction).

[0024] As shown in FIG. 1, the visual inspection device 100 includes a stage 10, an imaging unit 20, a table 30, a negative pressure measurement unit 33 (see FIG. 2), an air blowing unit 40, an air blowing unit lifting mechanism 41 (see FIG. 2), a defect detection unit 50, and a control unit 60.

[0025] The stage 10 moves the table 30 in the X and Y directions in FIG. 1 . The stage 10 includes an X-stage 11 and a Y-stage 12. The X-stage 11 is configured to move the Y-stage 12, which is arranged above it, in the left-right direction (X direction) in FIG. 1 . The Y-stage 12 is also configured to move the table 30, which is arranged above it, in the depth direction (Y direction) in FIG. 1 . In the following description, one side of the X direction is referred to as the X1 direction, and the other side as the X2 direction. The back side of the Y direction in FIG. 1 is referred to as the Y1 direction, and the front side is referred to as the Y2 direction. The height direction in FIG. 1 is referred to as the Z direction, and the upward direction in the Z direction is referred to as the Z1 direction, and the downward direction is referred to as the Z2 direction.

[0026] The table 30 adsorbs the semiconductor wafer W on the mounting surface of the semiconductor wafer W in order to mount and fix the semiconductor wafer W. As shown in Fig. 6, when the semiconductor wafer W is mounted on the table 30, the table 30 is moved to the X2 side by the stage 10, and the table 30 is positioned below the air blowing unit 40 (on the Z2 side).

[0027] The air blowing unit 40 also blows air onto the semiconductor wafer W. In the first embodiment, the position of the air blowing unit 40 relative to the table 30 is changeable. That is, the relative position in the vertical direction (Z direction) is changeable. The air blowing unit 40 is also configured to blow air so as to press the semiconductor wafer W placed on the surface of the table 30 against the surface of the table 30 in order to assist in fixing the semiconductor wafer W to the table 30 when the semiconductor wafer W is sucked onto the mounting surface.

[0028] The air blowing unit 40 is configured to blow compressed air. For example, an air source (positive pressure source) (not shown) is connected to the air blowing unit 40, and compressed air from the air source is supplied to the air blowing unit 40. For example, the air blowing unit 40 is an air blower connected to a compressor via an electro-pneumatic regulator that controls air pressure with an electric signal.

[0029] Furthermore, the air blowing unit lifting mechanism 41 moves the air blowing unit 40 in the Z direction. This allows the air blowing unit 40 to change its position relative to the table 30. For example, the air blowing unit lifting mechanism 41 moves the air blowing unit 40 up and down (in the Z direction) using the driving force of a motor. The air blowing unit lifting mechanism 41 is an example of the "lifting mechanism" in the claims.

[0030] Furthermore, the air blowing unit 40 is configured to be able to change at least one of the air blowing pressure and the compressed air blowing time, in addition to being able to change its position relative to the table 30. In the first embodiment, the air blowing unit 40 is configured to be able to change both the air blowing pressure and the compressed air blowing time.

[0031] The table 30 also has, at the center of the mounting surface on which the semiconductor wafer W is placed, a plurality of lift pins 31 (see FIG. 6) for placing the semiconductor wafer W transferred by the robot arm 70. A fine hole 30a (see FIG. 3) is formed in the mounting surface of the table 30 on which the semiconductor wafer W is placed. The fine hole 30a is connected to a negative pressure source 32 such as a vacuum pump. A negative pressure measuring unit 33 (see FIGS. 2 and 3) is also provided for measuring the negative pressure as the suction force between the table 30 and the semiconductor wafer W.

[0032] The imaging unit 20 captures an image of the appearance of the semiconductor wafer W. The imaging unit 20 is, for example, a two-dimensional camera.

[0033] The defect detection unit 50 detects defects in the semiconductor wafer W based on the appearance image captured by the imaging unit 20. The defect detection unit 50 detects defects in the semiconductor wafer W, for example, by comparing an image of a non-defective semiconductor wafer W without defects with the appearance image captured by the imaging unit 20.

[0034] 2 , the control unit 60 controls the stage 10, the negative pressure source 32, the air blowing unit 40, and the air blowing unit lifting / lowering mechanism 41. For example, the control unit 60 is a computer that includes a processor such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a GPU (Graphics Processing Unit), and enables control processing of the equipment. Note that, because detection of the semiconductor wafer W by the defect detection unit 50 is also a process that can be performed by a computer, the defect detection unit 50 may be configured to be included in the control unit 60.

[0035] In the visual inspection apparatus 100, in order to move the table 30 horizontally by the stage 10 while the semiconductor wafer W remains on the mounting surface of the table 30, it is necessary to fix the semiconductor wafer W to the mounting surface of the table 30. As shown in Fig. 3, the semiconductor wafer W is fixed to the mounting surface of the table 30 by creating a negative pressure in the fine holes 30a connected to the negative pressure source 32, thereby generating a suction force between the semiconductor wafer W and the mounting surface of the table 30.

[0036] Here, as shown in FIG. 4 , a semiconductor wafer W may develop warpage C during processing. For example, the warpage C of the semiconductor wafer W may be a convex warpage C in the upward direction (Z1 direction) as shown in FIG. 4( a ) or a concave warpage C in the upward direction (Z1 direction) as shown in FIG. 4( b ). The presence of warpage C may create a gap D between the semiconductor wafer W and the mounting surface of the table 30, making it impossible to fix the semiconductor wafer W using the negative pressure source 32. In reality, the warpage C of the semiconductor wafer W does not occur in one direction across the entire semiconductor wafer W as shown in FIG. 4( a ) or 4( b ). Instead, as shown in FIG. 5 , there are portions where the convex warpage C occurs and portions where the concave warpage C occurs. Fixing a semiconductor wafer W having warpage C to the mounting surface of the table 30 will be described below.

[0037] (Method of Fixing Semiconductor Wafer to Table) Next, a method of fixing the semiconductor wafer W to the table 30 in the first embodiment will be described with reference to FIGS.

[0038] In step S1 shown in Fig. 12, the control unit 60 raises the lift pins 31 on the table 30 as shown in Fig. 6. Then, the process proceeds to step S2.

[0039] 12, the control unit 60 places the semiconductor wafer W on the lift pins 31 on the table 30 by the robot arm 70, as shown in Figures 7 and 8. Thereafter, the process proceeds to step S3.

[0040] 12, the control unit 60 lowers the lift pins 31 on the table 30, and starts suction of the semiconductor wafer W to the table 30 by the negative pressure source 32, as shown in FIG. 8. Then, the process proceeds to step S4.

[0041] 12, the control unit 60, as shown in Fig. 3, measures the negative pressure as the suction force between the semiconductor wafer W and the mounting surface of the table 30 for the semiconductor wafer W using the negative pressure measurement unit 33. For example, the negative pressure measurement unit 33 measures the suction force between the semiconductor wafer W and the mounting surface of the table 30 by measuring the negative pressure in the fine hole 30a.

[0042] 12, if the magnitude of the negative pressure measured in step S4 exceeds a predetermined threshold value, the process flow for placing the semiconductor wafer W on the table 30 is terminated, and imaging by the imaging unit 20 is started to inspect the appearance of the semiconductor wafer W. If the magnitude of the negative pressure measured in step S4 does not exceed a predetermined threshold value, the process proceeds to step S6. Note that even when the process flow for placing the semiconductor wafer W on the table 30 is terminated, the semiconductor wafer W continues to be fixed by the negative pressure source 32 until inspection of the semiconductor wafer W is completed.

[0043] Next, in step S6 shown in Fig. 12, the control unit 60 controls the air blowing unit 40 to blow air when the magnitude of the negative pressure measured by the negative pressure measuring unit 33 does not exceed a predetermined threshold value, as shown in Fig. 9. That is, compressed air is blown by the air blowing unit 40. The control unit 60 is an example of a "blow control unit" in the claims. Then, the process proceeds to step S7.

[0044] In step S7 shown in FIG. 12, the control unit 60 causes the negative pressure measurement unit 33 to measure the negative pressure as the suction force between the semiconductor wafer W and the surface of the table 30 on which the semiconductor wafer W is placed.

[0045] 12, if the magnitude of the negative pressure measured in step S7 exceeds the previously acquired threshold value, the process flow for placing the semiconductor wafer W on the table 30 is terminated, the stage 10 moves the table 30 below the imaging unit 20 (in the Z2 direction), and imaging by the imaging unit 20 is started. If the magnitude of the negative pressure measured in step S7 does not exceed the previously acquired threshold value, the process proceeds to step S9. Note that even when the process flow for placing the semiconductor wafer W on the table 30 is terminated, the semiconductor wafer W continues to be fixed by the negative pressure source 32 until inspection of the semiconductor wafer W is completed.

[0046] 12, the control unit 60 controls the air blowing position, air blowing pressure, and air blowing time of the air blowing unit lifting / lowering mechanism 41, as shown in Figures 9 to 11, and then returns to the processing of step S6. For example, the air blowing position can be changed within a range of 65 mm to 85 mm from the surface of the table 30, the air blowing pressure can be changed among 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, and 0.45 MPa, and the air blowing time can be changed within a range of 0.1 s to 30 s.

[0047] 9 to 11, the air blowing range on the semiconductor wafer W can be changed by changing the air blowing position in the Z direction. With the air blowing position in FIG. 9 as the intermediate position, FIG. 10 shows the state in which the air blowing unit 40 has been moved upward (in the Z1 direction), and FIG. 11 shows the state in which the air blowing unit 40 has been moved downward (in the Z2 direction). R1 ​​represents the size of the air blowing range at the intermediate position, R2 represents the size of the air blowing range during upward movement, and R3 represents the size of the air blowing range during downward movement. R1 is smaller than R2 and larger than R3. In other words, the greater the distance between the air blowing unit 40 and the semiconductor wafer W, the larger the air blowing range. In FIGS. 9 to 11, the arrows extending from the air blowing unit 40 to the semiconductor wafer W represent compressed air, and the dashed circles represent the compressed air blowing range.

[0048] The operations from steps S6 to S9 are repeated until the magnitude of the negative pressure exceeds a preset threshold, whereby the visual inspection apparatus 100 fixes the semiconductor wafer W by suction onto the table 30.

[0049] (Effects of First Embodiment) In the first embodiment, the following effects can be obtained.

[0050] As described above, the appearance inspection apparatus 100 of the first embodiment includes the imaging unit 20, the table 30 on which the semiconductor wafer W is placed, the stage 10 that moves the table 30 in the X and Y directions in FIG. 1, the air blowing unit 40, the air blowing unit lifting mechanism 41 that raises and lowers the air blowing unit 40 in the Z direction in FIG. 1, the negative pressure source 32 that adsorbs and fixes the semiconductor wafer W to the table 30, and the negative pressure measuring unit 33 that measures the suction force between the semiconductor wafer W placed on the table 30 and the table 30. As a result, even if the semiconductor wafer W cannot be adsorbed and fixed to the table 30 due to a gap D that occurs between the semiconductor wafer W and the table 30 due to the presence of a warp C in the semiconductor wafer W, the air blowing section 40 arranged in the Z1 direction of the table 30 blows compressed air in the Z2 direction, which is the direction that presses the semiconductor wafer W against the table 30, thereby correcting the warp C of the semiconductor wafer W, thereby eliminating the gap D between the semiconductor wafer W and the table 30 and allowing the semiconductor wafer W to be adsorbed and fixed to the table 30.

[0051] Furthermore, in the first embodiment, compressed air is blown by the air blowing unit 40, so that air can be blown with a stronger force than when uncompressed air is blown. Therefore, even when the warpage C of the semiconductor wafer W is large or when the semiconductor wafer W has hardened due to a heat treatment or the like, and blowing uncompressed air is not strong enough to correct the warpage C, the warpage C of the semiconductor wafer W can be corrected, and the semiconductor wafer W can be fixed by suction to the table 30.

[0052] Furthermore, in the first embodiment, the air blowing unit 40 is configured to be movable in the Z direction, which is the up-down direction, by the air blowing unit lifting mechanism 41. As a result, even if it is difficult to correct the warpage C of the semiconductor wafer W by blowing compressed air from a fixed position depending on the state of the warpage C of the semiconductor wafer W, it is possible to deal with various warpages C of the semiconductor wafer W by changing the blowing position of the compressed air by the air blowing unit 40 using the air blowing unit lifting mechanism 41 and blowing compressed air.

[0053] Furthermore, in the first embodiment, in addition to changing the blowing position of the air blowing unit 40 by the air blowing unit lifting mechanism 41, the air blowing unit 40 is configured to be able to change the pressure and blowing time of the compressed air under the control of the control unit 60. As a result, even if it is difficult to correct the warp C of the semiconductor wafer W by simply changing the blowing position depending on the state of the warp C of the semiconductor wafer W, it is possible to deal with various warp C of the semiconductor wafer W by changing the blowing pressure and blowing time of the compressed air.

[0054] Furthermore, in the first embodiment, the negative pressure is measured by the negative pressure measuring unit 33 as the suction force between the semiconductor wafer W and the table 30, and when the magnitude of the negative pressure does not exceed a pre-acquired threshold value, air is blown by the air blowing unit 40. As a result, when the magnitude of the negative pressure does not exceed the pre-acquired threshold value, that is, when the suction between the semiconductor wafer W and the table 30 is insufficient, the air blowing unit 40 blows compressed air, thereby suppressing the blowing of compressed air when it is not necessary.

[0055] Second Embodiment Next, a description will be given of the fixation of a semiconductor wafer W to a table 30 by a visual inspection apparatus 100a according to a second embodiment. As shown in FIG. 13 , the visual inspection apparatus 100a used in the visual inspection method according to the second embodiment has the same configuration as the visual inspection apparatus 100 shown in FIG. 1 , except that it further includes an air blowing unit horizontal movement mechanism 42 that moves the air blowing unit 40 in horizontal directions (X and Y directions) and a control unit 60a that controls the air blowing unit horizontal movement mechanism 42. In the second embodiment, the configuration is the same as in the first embodiment up to step S5 of the first embodiment. In the first embodiment, the positional relationship between the air blowing unit 40 and the table 30 in the horizontal (X and Y) directions remains unchanged. However, in the second embodiment, the control unit 60a is configured to control the air blowing unit 40 and the air blowing unit horizontal movement mechanism 42 so that the air blowing unit 40 moves in the X and Y directions while blowing compressed air (see FIGS. 14 and 15 ). For example, the air blowing unit horizontal movement mechanism 42 moves the air blowing unit 40 in the horizontal direction (X and Y directions) by the driving force of a motor. The air blowing unit horizontal movement mechanism 42 is an example of a "horizontal movement mechanism" in the claims. In Figures 14 and 15, the arrows extending from the air blowing unit 40 to the semiconductor wafer W represent compressed air, and the dashed circle represents the blowing range of the compressed air.

[0056] As shown in FIGS. 16 to 18 , in the second embodiment, the control unit 60 a is configured to control the air blowing unit 40 and the air blowing unit horizontal movement mechanism 42 so that the compressed air blown by the air blowing unit 40 onto the semiconductor wafer W placed on the table 30 follows a predetermined trajectory. As shown in FIG. 16 , in the second embodiment, the air is blown along a predetermined trajectory, which is generally in the shape of the letter "e." As shown in FIGS. 17 and 18 , the blowing of compressed air begins from the center of the semiconductor wafer W, and the air is blown onto the semiconductor wafer W along the predetermined trajectory, which is generally in the shape of the letter "e." In FIGS. 17 and 18 , the arrow extending from the air blowing unit 40 to the semiconductor wafer W represents the compressed air, and the dashed circle represents the range of the compressed air blown.

[0057] (Effects of Second Embodiment) In the second embodiment, the following effects can be obtained.

[0058] In the second embodiment, the air blowing unit 40 moves in the horizontal direction (X and Y directions) to blow compressed air to any point in the horizontal direction of the semiconductor wafer W placed on the table 30. This makes it possible to blow compressed air to all of the warpage C even in cases where it is difficult to blow compressed air to all of the warpage C simply by blowing compressed air from a position fixed in the horizontal direction, such as when warpage C occurs over the entire semiconductor wafer W. As a result, even when warpage C occurs over the entire semiconductor wafer W, the semiconductor wafer W can be fixed by suction to the table 30.

[0059] In the second embodiment, the control unit 60a is configured to control the air blowing unit 40 and the air blowing unit horizontal movement mechanism 42 so that the compressed air blown by the air blowing unit 40 onto the semiconductor wafer W placed on the table 30 follows a predetermined trajectory that has been set in advance. Therefore, a predetermined trajectory can be set according to the state of warpage C of the semiconductor wafer W, which differs depending on the type of processing. As a result, semiconductor wafers W with different states of warpage C depending on the processing step can be adsorbed and fixed to the table 30.

[0060] Furthermore, in the second embodiment, the air is blown onto the semiconductor wafer W in a predetermined shape that is approximately an "e" shape. Therefore, the air can be blown along a trajectory that pushes the air between the semiconductor wafer W and the table 30 outward from the center of the semiconductor wafer W, so that the semiconductor wafer W and the table 30 can be efficiently brought into close contact with each other. As a result, the semiconductor wafer W can be efficiently fixed by suction to the table 30.

[0061] The other effects of the second embodiment are the same as those of the first embodiment.

[0062] Third Embodiment Next, the fixing of a semiconductor wafer W to a table 30 by a visual inspection apparatus 100b according to a third embodiment will be described. As shown in Fig. 18, the visual inspection apparatus 100b used in the visual inspection method according to the third embodiment has the same configuration as the visual inspection apparatus 100 shown in Fig. 1, except that it is provided with two air blowing units 40. In Fig. 19, the arrows extending from the air blowing units 40 to the semiconductor wafer W represent compressed air, and the dashed circle represents the blowing range of the compressed air.

[0063] (Effects of the Third Embodiment) In the third embodiment, the following effects can be obtained.

[0064] In the third embodiment, a plurality of air blowing units 40 are provided above the table 30 (in the Z1 direction), and each of the plurality of air blowing units 40 is configured to blow air at a different portion of the semiconductor wafer W placed on the table 30. Therefore, even if it is difficult to correct the warpage C of the semiconductor wafer W by blowing air from only one location depending on the state of the warpage C of the semiconductor wafer W, it is possible to deal with various types of warpage C of the semiconductor wafer W by blowing air at a plurality of locations on the semiconductor wafer W using the plurality of air blowing units 40.

[0065] The other effects of the third embodiment are the same as those of the first embodiment.

[0066] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above-mentioned embodiments, and further includes all modifications (modifications) within the meaning and scope of the claims.

[0067] For example, in the first to third embodiments, an example was shown in which the air blower, which is the air blowing unit 40, blows compressed air, but the present invention is not limited to this. In the present invention, for example, the air blowing unit 40 may be configured by a fan, an air blower, or the like, and the semiconductor wafer W may be pressed against the table 30 by blowing uncompressed air.

[0068] In the first embodiment, the relative positions of the air blowing unit 40 and the table 30 are changed by moving the air blowing unit 40 up and down (Z direction) using the air blowing unit lifting mechanism 41 or by moving the table 30 horizontally (XY direction) using the stage 10, but the present invention is not limited to this. For example, the present invention may be configured such that the air blowing position is changed by the air blowing unit 40 swinging.

[0069] In the first embodiment, the relative position between the table 30 and the air blowing unit 40, the pressure of the compressed air blowing, and the air blowing time are all changed, but the present invention is not limited to this. For example, any one of the relative position between the table 30 and the air blowing unit 40, the pressure of the compressed air blowing, and the air blowing time may be changed. Also, other conditions, such as the rhythm and timing of the air blowing, may be changed.

[0070] In the first to third embodiments, the negative pressure is measured as the chucking force between the table 30 and the semiconductor wafer W, and compressed air is blown when the magnitude of the negative pressure does not exceed a threshold value, but the present invention is not limited to this. A configuration in which compressed air is blown without measuring the negative pressure is also possible.

[0071] Furthermore, in the third embodiment, an example was shown in which two air blowing units 40 were provided as the multiple air blowing units 40, but the present invention is not limited to this. For example, five air blowing units 40 may be arranged in a cross shape. Specifically, as shown in FIG. 20 , an air blowing unit 40 that blows compressed air to the center of the semiconductor wafer W may be provided in each of the X1 direction, X2 direction, Y1 direction, and Y2 direction. Furthermore, the number of air blowing units 40 may be other than two or five.

[0072] In the third embodiment, an example is shown in which multiple air blowing units 40 blow air onto different portions of the semiconductor wafer W, but the present invention is not limited to this. Multiple air blowing units 40 may blow compressed air onto the same portion of the semiconductor wafer W.

[0073] In the first to third embodiments, the compressed air is blown so that the mounting surface of the semiconductor wafer W and the blowing direction of the compressed air from the air blowing unit 40 are substantially perpendicular to each other, but the present invention is not limited to this. As long as the compressed air can be blown so as to press the semiconductor wafer W against the table 30, the angle between the mounting surface of the semiconductor wafer W and the blowing direction of the compressed air from the air blowing unit 40 may be any angle.

[0074] In the second embodiment, the air blowing unit 40 blows compressed air onto semiconductor wafers W whose state of warpage C varies depending on the processing step while moving the air blowing unit 40 along a predetermined trajectory that has been set in advance. However, the present invention is not limited to this. The state of warpage C of each semiconductor wafer W may be measured in advance for each semiconductor wafer W, and the trajectory along which the air blowing unit 40 moves may be set for each semiconductor wafer W.

[0075] REFERENCE SIGNS LIST 10 Stage 20 Imaging unit 30 Table 30a Fine hole 32 Negative pressure source 33 Negative pressure measuring unit 40 Air blowing unit 41 Air blowing unit lifting mechanism (lifting mechanism) 42 Air blowing unit horizontal movement mechanism (horizontal movement mechanism) 60, 60a Control unit (blow control unit) 100, 100a, 100b Visual inspection device C Warpage W Semiconductor wafer (object)

Claims

1. An appearance inspection device comprising: an imaging unit that captures an appearance image of a wafer; a table that adsorbs the wafer on the wafer placement surface to place and secure the wafer; a defect detection unit that detects defects in the wafer based on the appearance image; and an air blowing unit that blows air onto the wafer, wherein the air blowing unit is capable of changing its position relative to the table and is configured to blow air at the wafer placed on the surface of the table to press the wafer against the surface of the table in order to assist in securing the wafer to the table when adsorbing the wafer on the placement surface.

2. The visual inspection device according to claim 1, wherein the air blowing section includes a compressed air blowing section that blows compressed air as the air.

3. The visual inspection device according to claim 1, further comprising an elevation mechanism for moving the air blowing unit in the vertical direction so as to change the position of the air blowing unit relative to the table.

4. An appearance inspection device as described in claim 1, wherein the air blowing unit is configured so that, in addition to being able to change its position relative to the table, at least one of the air blowing pressure and air blowing time can be changed.

5. An appearance inspection device as described in claim 1, further comprising: a negative pressure measuring unit that measures the negative pressure as the suction force of the wafer to the table when the table suctions the wafer; and a blowing control unit that controls the air blowing unit to blow air when the magnitude of the negative pressure measured by the negative pressure measuring unit does not exceed a predetermined threshold value that has been set in advance.

6. The visual inspection device according to claim 1, further comprising a horizontal movement mechanism for moving the air blowing unit horizontally, as a configuration for changing the position relative to the table.

7. The visual inspection device according to claim 6, wherein the air blowing unit is configured to be movable horizontally by the horizontal movement mechanism while blowing air.

8. An appearance inspection device as described in claim 7, wherein the air blowing unit is configured to be able to blow air onto the wafer placed on the surface of the table while moving the air blowing unit horizontally along a predetermined trajectory using the horizontal movement mechanism.

9. The visual inspection device according to claim 1, wherein a plurality of the air blowing units are provided, and the plurality of air blowing units are configured to blow air to different locations of the wafer placed on the surface of the table.

10. A control method for an appearance inspection device, comprising: a step of placing a wafer; a step of sucking the wafer to fix the wafer to a mounting surface; a step of blowing air onto the wafer to press it against the mounting surface when sucking the wafer to assist in fixing the wafer to the mounting surface; and a step of changing the position at which the air is blown onto the wafer.

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