JP2007240264A - Observation device and flaw inspection device of edge face - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an observation device which exerts no effect on the edge face part of a substrate because the observation device is not brought into contact with the edge face part of the substrate and enables the observation adapted even to the surface deflection or the like caused by the shape such as warpage or the like of a wafer, and a flaw inspection device of the edge face of the substrate. <P>SOLUTION: The observation device includes an imaging device for imaging the edge face part of the substrate, a rotatable holding part for holding the substrate, a displacement detection part for detecting the fluctuation quantity of the position of the edge face part of the substrate, a display part for displaying the captured image and a control part for performing control so that the image of the edge face of the substrate, which is captured by the imaging part, is observed on the display part at a definite position on the basis of the signal from the displacement detection part. The edge face flaw inspection device is also disclosed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an observation apparatus and a defect inspection apparatus for imaging and inspecting an end face portion such as an end face or a chamfered portion of a substrate such as a wafer.

  In general, a silicon wafer, a glass wafer, or the like is used as a substrate of a semiconductor device. The substrate surface of these substrates is observed with a microscope or the like during the manufacturing process, and the presence or absence of chips and cracks, adhesion of foreign matters, and the like are inspected.

  Due to recent advances in semiconductor manufacturing technology, the size of a wafer has been increased and the diameter has increased to 300 mm while satisfying the high integration and multi-functionality of semiconductor devices. Along with this, wafer management has become more important. This is because the number of chips produced per wafer has increased considerably, so that the completed wafer becomes expensive, and even if one wafer is cracked, great damage occurs.

  In addition, the semiconductor manufacturing apparatus is automatically transported and automatically processed by computer management, and many processes are performed in vacuum. Therefore, when a wafer crack occurs, it takes time to remove the broken wafer, and it takes time to recover and restart the wafer. Furthermore, the production line may stop depending on the location (apparatus) where the wafer crack occurred. In particular, when wafer cracking occurs in a clean room, powdery wafer pieces become particles, enter into other production lines, and adhere to products in the middle of production, thus adversely affecting them.

  This wafer cracking is caused by temperature stress or heat treatment caused by heat treatment in the manufacturing process when a wafer edge surface portion or an edge portion of the wafer called an outer peripheral edge portion is caused by a collision with another object during transportation. The cause is considered to be mechanical stress applied by back grinding.

There is known a technique that specially detects defects such as chips, cracks, scratches, and the like on the end surface of the wafer and unnecessary portions of the resist, and foreign matter adhesion defects. For example, Patent Document 1 discloses a plurality of cameras that image different portions in the thickness direction of the peripheral edge of the wafer and a plurality of cameras that image different portions in the thickness direction of the notch in order to image the peripheral edge of the wafer. An inspection apparatus including the above is disclosed. Further, Patent Document 2 includes a plurality of optical systems with an autofocus mechanism for observing the stage and the wafer in order to accurately and easily perform observation of at least one of the peripheral portion, side surface, and lower portion of the wafer. An observation device is disclosed.
JP 2003-243465 A Japanese Patent Laid-Open No. 2001-221749

  However, there are concerns about the following in the conventional technology described above. The inspection apparatus according to Patent Document 1 has a plurality of support portions for supporting the peripheral edge of the wafer on a circumference centering on the central axis of rotation, in the support portion that rotatably supports the disk-shaped wafer, As a result, the wafer to be inspected is supported. This indicates that the peripheral edge of the wafer is in contact with the support portion. This may also cause defects such as adhesion of foreign matter and scratches at the peripheral edge. Furthermore, there is a problem that it takes time because it is necessary to pick up the part to be inspected.

  The observation apparatus according to Patent Document 2 has an alignment mechanism, and the center of the wafer is positioned approximately at the rotation center of the drive mechanism by this alignment mechanism. It is disclosed that an operation capable of always measuring a predetermined distance from the outer periphery of the wafer is performed in conjunction with the driving mechanism. However, the wafer is not necessarily a perfect plane, and the outer peripheral portion moves up and down in the normal direction of the wafer surface due to warpage of the wafer. That is, even if it can cope with the eccentricity of the end face part due to rotation, it cannot cope with the vertical movement of the end face part due to rotation in the normal direction (hereinafter referred to as surface runout). For this reason, particularly when the end surface of the wafer is imaged from the side perpendicular to the normal direction of the wafer, the image of the end surface displayed on the display unit moves up and down and is difficult to observe. In the imaging using, even if the focus is achieved by the automatic focusing mechanism, the observation site may come off from the screen of the display unit, which may hinder the observation and inspection of defects.

  Accordingly, the present invention provides an observation apparatus and an end face defect inspection that do not affect the end face portion of the substrate and that do not affect the end face portion, and that can be applied to surface deflection due to the shape of the wafer warp or the like. An object is to provide an apparatus.

  In order to achieve the above-mentioned object, the present invention provides an imaging device that images the end surface portion of a substrate, a holding portion that holds the substrate and is rotatable about the normal line of the substrate, and a rotation of the holding portion. A displacement detection unit that detects a change in the position of the end face of the substrate that occurs, a display unit that displays an image captured by the imaging device, and an image that is captured by the imaging device based on a signal from the displacement detection unit There is provided an observation device and an end surface defect detection device, comprising: a control unit configured to control an image of the end surface portion of the substrate that is observed at a certain position on the display unit.

  The observation apparatus having the above configuration images the end surface portion of the substrate mounted on the holding unit with the imaging device, and displays the imaged end surface portion of the substrate on the display unit. At this time, the position of the end surface displayed on the display unit is observed at a fixed position based on the signal from the displacement detection unit that detects the change in the position of the end surface of the substrate caused by the rotation of the holding unit. The imaging is performed while being controlled by the control unit.

  According to the present invention, an observation device and an end surface defect inspection device that do not affect the end surface portion of the substrate and that do not affect the end surface portion and can perform observation adapted to surface fluctuations due to the shape of the wafer and the like. Can be provided.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.
FIG. 1 is a diagram showing a schematic configuration of an observation apparatus according to a first embodiment of the present invention viewed from the normal direction of a substrate. FIG. 2 is a side view of the observation apparatus of the present embodiment as viewed from a direction orthogonal to the normal direction of the main surface of the wafer 2.

  In addition, the end surface portion described below means that the end surface (side surface) of the substrate and the front and back surface portions and chamfers around the end surface are chamfered portions, the front and back surfaces around the end surface, and unnecessary resist at the peripheral portion after resist application. It is assumed that the portion removed with a rinse liquid also includes an edge cut portion or a portion called a rinse cut portion. This observation apparatus includes an imaging optical system 1 and an imaging unit 3 that photoelectrically converts an image of an end surface portion of a wafer 2 (substrate) imaged by the imaging optical system 1 to generate an image signal. The imaging optical system 1 and the imaging unit 3 constitute an optical module 14 (imaging device). An image processing unit 4 that generates image data from the generated image signal and a display unit 5 that displays the image data generated by the image processing unit 4 are provided. Then, the optical module 14 is installed, and a moving mechanism 6 (a moving mechanism or an imaging device moving mechanism) that moves around the end surface portion around a certain point on the end surface portion of the wafer 2 or moves in the front-rear direction along the optical axis. ) And a moving mechanism control unit 7 for driving and controlling the moving mechanism 6. Furthermore, a rotary table 12 that can be rotated with the wafer 2 mounted thereon, and a position sensor 8 (displacement detector) that detects the amount of eccentricity in the direction of the optical axis when the end surface portion of the wafer 2 placed on the rotary table 12 is rotated. ), A position sensor 9 (displacement detection unit) for detecting the surface shake of the end surface portion of the rotating wafer 2, a base 10 on which the moving mechanism 6 and the optical module 14 are installed, and the entire components of the apparatus are controlled. It is comprised with the control part 11. FIG.

  The imaging optical system 1 includes an optical lens such as an objective lens and an imaging lens, a half mirror for guiding illumination light to a wafer, and the like. The observation image in the imaging optical system 1 does not need a magnification at the level of a stereomicroscope, and has a magnification equivalent to 5x (NA: 0.15), 10x (NA: 0.3), and 20x (NA: 0.35). Can be adopted.

  The imaging unit 3 is provided with an imaging element 28 that generates an image signal of an image of the end surface portion of the wafer 2 by photoelectric conversion. A solid-state image sensor such as a CCD is employed as the image sensor 28. The image sensor may be an area sensor arranged two-dimensionally in the vertical and horizontal directions, or may be a line sensor arranged one-dimensionally. In the case of a line sensor, the one-dimensional longitudinal direction coincides with a rotating surface described later.

  The optical module 14 (imaging device) is composed of the imaging optical system 1 and the imaging unit 3 and performs imaging of the end face part. The optical module 14 may have an autofocus function and a zooming function as necessary. The image processing unit 4 performs various image processing based on preset application software to generate desired image data. The display unit 5 is a monitor and displays an image captured by the optical module 14. A touch panel is provided on the screen of the display unit 5, and an instruction or the like can be input by touching a displayed instruction button image.

  The position sensor 8 and the position sensor 9 are disposed at a position close to the wafer 2 to be placed below the XY table 12 shown in FIG. Specifically, the position sensors 8 and 9 are support members installed on the gantry so that the outer peripheral end of the main surface of the wafer 2 and the main surface slightly inside from the outer peripheral end become detection points. Is arranged. However, as long as the position sensor 8 can detect the amount of eccentricity of the wafer 2 and the position sensor 9 can detect the amount of surface deflection of the wafer 2, they may be arranged side by side at the peripheral edge.

  The position sensor 8 is a known transmission type detector for detecting the amount of eccentricity of the wafer 2, and includes a light emitting element and a light receiving element facing each other across the wafer end surface. Light is irradiated to the end surface portion of the wafer 2 rotated by the rotating shaft 13 of the turntable 12, and the amount of light received without being blocked from the end surface portion is detected.

The position sensor 8 may be a reflective detector in which the light receiving unit and the light transmitting unit are integrated and the wear is disposed on the same side of the end surface. In addition, if an autofocus function is installed, it is possible to cope with a focus shift due to eccentricity.
The position sensor 9 is a well-known optical length measurement sensor, and detects the amount of surface deflection (variation in the distance from the position sensor 9 to the main surface of the wafer 2) in the rotating wafer 2.

  The moving mechanism 6 (moving mechanism or imaging device moving mechanism) is equipped with an optical module 14. A drive mechanism is provided that moves to correct based on the amount of eccentricity and the amount of surface deflection detected by the position sensor 8 and the position sensor 9. In other words, the first drive mechanism that moves the optical module 14 in the optical axis direction at a high speed in a minute direction and the optical module 14 at a high speed in the longitudinal direction (normal direction of the substrate) perpendicular to the main surface of the wafer 2. A second drive mechanism that moves minutely. Note that the moving mechanism for correcting the eccentricity and the surface runout may be separate from the moving mechanism 6.

  The turntable 12 is a circular stage that holds the back surface of the wafer 2 by suction. A wall portion is formed along the outer periphery of the wafer mounting portion, and the wall portion contacts the back surface of the wafer 2. A large number of pins are arranged on the inner diameter side, and the diameter of the rotary table 12 that supports the back surface of the wafer to be flat is smaller than the diameter of the substrate, so that the end surface portion of the back surface of the wafer can be observed. It is desirable that the diameter of the wafer is as large as possible so that the end face of the back surface can be observed at a minimum. In particular, if the table diameter is 90% or more of the wafer diameter and the entire surface of the table can be sucked, it is possible to prevent the observation position from being displaced due to the warpage of the wafer. In order to deliver the wafer by the robot arm, a mechanism for raising and lowering a plurality of pins and the table may be provided at the center of the table.

  And the rotating shaft 13 rotates with the motor which is not shown in figure, and a mounting part rotates. Further, an encoder for detecting the rotation angle may be mounted so that the angle can be detected and transmitted to the control unit. The rotary table 12 may be the same as the rotary XY stage of a micro inspection unit using a microscope of a known visual inspection apparatus.

The base 10 is a plate-like member installed on a gantry portion (not shown), and a guide rail is disposed on the plane. And the movement mechanism 6 is rotatably installed through a guide rail.
The control unit 11 controls the entire observation apparatus such as correcting the eccentricity and the positional deviation due to the surface deviation caused by the wafer rotation and the eccentricity when the wafer is rotated, and performing the rotation operation so that an appropriate angle can be observed. Do. The moving mechanism control unit 7 and the image processing unit 4 are integrally included, and they may be composed of a personal computer. The control unit 11 is registered with a pre-measured data table or the like for detecting the amount of eccentricity or notch position when the wafer 2 is rotated.

  Next, the rotational movement of the moving mechanism 6 will be described. As shown in FIG. 2, the base 10 is provided with arc-shaped guide rails 18. The moving mechanism 6 is configured to rotate on the guide rail 18 by driving a motor such as a linear motor. That is, the moving mechanism 6 includes a rotation moving mechanism as a third drive mechanism. Here, the rotation axis passes through the point O and is perpendicular to a plane including the rotation axis of the rotary table 12 and the optical axis of the imaging optical system. That is, an arm mechanism that swings (rotates and moves) like a wiper may be provided, and the moving mechanism 6 may be disposed on the arm mechanism.

  In addition, if the optical axis of the imaging optical system 1 rotates around the point O in a plane including the central axis of rotation of the turntable 12 and the optical axis of the optical module 14, it can be rotated by various mechanisms. Can be realized.

  Further, the position of the rotation axis is a position where the optical axis of the imaging optical system 1 is slightly inside the wafer from the position where the optical axis of the imaging optical system 1 reaches the end surface of the wafer 2. As shown in FIG. 2B, the position of the rotation axis is such that the optical axis of the imaging optical system 1 when rotated about this rotation axis is orthogonal to the chamfered portions on the end surface, front surface, and back surface. The distance from the point O (rotation axis) is set to be equal. Accordingly, even if the rotational movement is performed, the distance between the end surface portion and the imaging optical system 1 can be kept substantially constant by setting the focusing position of the imaging optical system 1 to the end surface or the chamfered portion.

  Depending on the shape of the chamfer, the distance between the end face and the imaging optical system 1 may not be substantially constant, and if the distance from the depth of field of the optical module is deviated, the focusing distance may be adjusted by an autofocus mechanism. .

  Further, the moving mechanism 6 rotates and moves at a rotation swing angle desired or based on the design in an axial direction orthogonal to the main surface of the wafer. The rotation angle range is desirably about 90 ° to 180 °. In particular, in order to observe the rinse cut amount on the wafer surface, it is desirable that the angle range is observable from the direction perpendicular to the main surface.

  As described above, the optical axis of the imaging optical system 1 moves from the surface of the wafer 2 through the end surface to the back surface, or from the back surface through the end surface to the surface. Thereby, the optical module 14 of the observation apparatus according to the present embodiment continuously places the end surface of the wafer 2 and the front and back surfaces connected to the end surface into the observation field of view of the imaging optical system 1 around the rotation axis passing through the point O. be able to.

  Next, a configuration example of the optical module 14 will be shown and described. FIG. 3 is a view of the optical module 14 viewed from the normal direction of the main surface of the wafer 2. The optical module 14 is configured by mounting the imaging optical system 1 and the imaging unit 3 on a lens mount body 21. The imaging optical system 1 and the imaging unit 3 are both attached to the lens mount body 21 so as to be easily detachable using a mount screw or the like. Further, the lens mount main body 21 is mounted on the moving mechanism 6.

  The imaging optical system 1 includes an objective lens 22, a half mirror 23, and an imaging lens 24. The optical axis of the objective lens 22 is deflected by 90 ° by the half mirror 23 so that it goes toward the imaging lens 24. Be placed. As the objective lens 22, one objective lens is used when observing the end surface of the wafer 2 and the front and back surfaces from an oblique direction. If necessary, a plurality of objective lenses having different magnifications may be used.

  In addition, a lens 25 for condensing illumination light and a light emitting diode (LED) 26 for emitting illumination light are detachably attached to the lens mount body 21 behind the half mirror 23 as viewed from the objective lens 22. Yes. The LED 26 has a light quantity and directivity capable of capturing an image of the end surface of the wafer 2 with sufficient brightness.

  Further, a light shielding cover 27 for preventing wetting to the outside is provided as appropriate so as to cover the LED 26 so that the illumination light emitted from the LED 26 does not adversely affect the inspection. Furthermore, the illumination is provided with a plurality of LED illuminations 29 at the periphery of the mirror of the objective lens 2. In addition, a ring illumination 19 is provided around the LED 26 so that an illumination that is easy to observe can be selected as appropriate. In other words, individual observation or observation under a plurality of combined illuminations is performed using coaxial down-angle illumination by the LED 26, oblique illumination from the side of the observation optical system by the LED illumination 29, and dark field illumination by the ring illumination 19. You can also.

  Next, the operation of the observation apparatus configured as described above will be described. First, the illumination light emitted from the LED 26 is collected by the lens 25. Then, the light passes through the half mirror 23 and is further irradiated as a parallel light flux from the objective lens 22 onto the wafer 2 to be observed. The light reflected by the wafer 2 enters the objective lens 22. The light beam from the objective lens 22 is deflected by the half mirror 23 and travels toward the imaging lens 24. The imaging lens 24 forms an image of the light flux on the light receiving surface of the image sensor (CCD) 28 in the imaging unit 3. The image sensor 28 generates an image signal of the end surface portion of the wafer 2 by photoelectric conversion. The image processing unit 4 performs various image processing on the generated image signal based on preset application software to generate image data, and displays the image data on the display unit 5 with a screen configuration described later. .

  A correction operation in the case where the center of the wafer 2 placed on the rotary table 12 is eccentric with respect to the axis of the rotation center and the wafer 2 is warped will be described. Here, as shown by the solid line in FIG. 2, the optical module 14 is arranged so that the optical axis is oriented in a direction perpendicular to the central axis of rotation of the turntable 12 so as to observe the end face.

  First, when the turntable 12 starts to rotate, the position sensor 8 transmits a signal of the detected light amount at that time to the control unit 11 in real time. Since the wafer 2 is eccentric, the amount of light that blocks the position sensor 8 changes. The control unit 11 that controls the sensor obtains the eccentric amount (variation amount) of the wafer 2 from the data table based on the light amount signal received from the position sensor 8. Then, the control unit 11 calculates the movement amount of the first drive mechanism of the movement mechanism for correcting the obtained eccentricity amount and issues an instruction to the movement mechanism control unit 7. The movement mechanism control unit 7 controls the first drive mechanism of the movement mechanism 6 based on the received movement amount signal for correction so that the distance between the wafer end surface and the imaging optical system 1 is always constant. To do. That is, the image of the end face in a state where the focused state is maintained is displayed on the display unit.

  Similarly, the position sensor 9 transmits a signal of the distance between the current position sensor 9 and the wafer end surface (periphery of the main surface) to the control unit 11 in real time. Since the wafer 2 is warped, the distance detected by the position sensor 9 changes. The control unit 11 obtains the distance from the end face of the wafer 2 from the data table based on the distance (surface runout amount, variation amount) signal received from the position sensor 9. The movement amount of the second drive mechanism of the movement mechanism for correcting the obtained change in distance is calculated, and an instruction is issued to the movement mechanism control unit 7. The movement mechanism control unit 7 controls the second driving mechanism of the movement mechanism 6 based on the received movement amount signal for correction, and always controls the position sensor 9 and the wafer end surface portion (periphery portion of the main surface). Make the distance constant. That is, the end face image is displayed at a fixed position on the display unit.

  The position of the optical module 14 is indicated by the solid line in FIG. 2A. However, for example, when the optical module 14 is in a direction perpendicular to the main surface of the wafer 2, the last of the first drive mechanism and the second drive mechanism. “The image of the end face in a state where the focused state is maintained is displayed on the display unit” and “the image of the end surface part is displayed at a certain position on the display unit” are switched. In addition, when it is in an oblique observation position, an image of the end face in a state where the first drive mechanism and the second drive mechanism act simultaneously to keep the focused state is displayed on the display unit. The image of the end face is displayed at a fixed position on the display unit ”. As described above, the relative position between the end face of the wafer 2 and the imaging optical system is kept constant regardless of the rotation position of the optical module 14, and the relative distance and the angle of the observation optical axis are almost constant. Therefore, the display can be displayed in a focused state with the end face part kept at a certain position on the display screen of the display part.

  Further, since these operations are performed at high speed, they are not recognized as long as the display unit is observed. With respect to the notch portion, the position sensor 8 causes a large change in the amount of light. Therefore, the large change in the amount of light may be recognized as the notch portion and the movement mechanism 6 may not be operated. Further, if the wafer 2 is a slight warp and can be handled by the rotational movement mechanism, the rotational movement may be performed by the rotational movement mechanism instead of the second driving mechanism. In the description of the present embodiment, the position variation is detected and corrected in real time. However, the rotary table 12 is provided with an encoder for detecting a rotation angle, and is rotated 360 ° in advance, that is, once in a notch. After acquiring the position, surface shake amount, and eccentricity data and storing the correction amount, imaging may be performed while correcting the eccentricity and the surface shake for each rotation angle of the rotary table 12.

  In the first embodiment, the moving mechanism 6 on which the optical module 14 is installed is moved in a plane including the rotation axis of the rotary table 12 and the optical axis of the imaging optical system. Can be used as a single end face defect inspection device. Further, by disposing the rotary table 12 of the present observation apparatus in the vicinity of the rotary table of a general rotary table, it can be used as an end face defect inspection apparatus without introducing a dedicated end face defect inspection apparatus. Therefore, it is possible to construct an end face defect detection device easily and inexpensively.

Next, a second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 4 is a diagram showing a schematic configuration of an observation apparatus according to the second embodiment of the present invention viewed from the normal direction of the substrate. The observation apparatus according to the second embodiment will be described on the assumption that the rotatable XY rotation stage provided in the substrate appearance inspection apparatus is shared as the rotary table 12.

  Here, only the configuration different from that of the first embodiment will be described, and the common configuration will be omitted. The changes from the first embodiment are that the first drive mechanism of the moving mechanism 6 is omitted, and the rotating shaft 13 of the rotary table 12 is installed in the XY stage unit 15 (moving mechanism or holding unit moving mechanism). As a result, the rotary table 12 can be moved in the XY plane, and the movement of the XY stage 15 as the moving mechanism in the X direction is observed via the moving mechanism control unit 7 when the end surface portion is observed. It is controlled by.

  This can be considered as the movement of the first drive mechanism of the movement mechanism 6 in the first embodiment replaced with the movement of the XY stage 15 in the X direction.

  In the second embodiment, the moving mechanism can be omitted by additionally mounting the present observation apparatus on an apparatus having an XY rotation stage, and an end face defect inspection apparatus can be constructed at a low cost.

  As a modification, the first and second driving mechanisms of the moving mechanism 6 are omitted, and the moving direction of the XY stage 15 (moving mechanism or holding unit moving mechanism) that is the moving mechanism of the rotary stage 12 is added to the XY plane. A mechanism that can also move in the Z-axis direction may be provided, and the movement may be controlled in the X and Z directions by the control unit 11 via the movement mechanism control unit 7.

  The movement of the first driving mechanism of the moving mechanism 6 of the first embodiment is replaced with the movement of the XY stage 15 in the X direction, and the movement of the second driving mechanism of the moving mechanism 6 is replaced with the movement of the XY stage 15 in the Z direction. It will be. Similar to the second embodiment, if it is additionally attached to an apparatus having an XYZ rotary stage, the moving mechanism can be omitted, and an end face defect inspection apparatus can be realized at low cost.

  FIG. 5 shows a screen configuration example of image data displayed on the display unit in the present invention. As shown in FIG. 5, the processed image data and information related to the image data are displayed separately on the screen 30 of the display unit 5. In this screen configuration, the front oblique surface (main surface surface) image 31, the end surface (side surface) image 32, and the back oblique surface (main surface rear surface) image 33 at the outer peripheral end of the wafer 2 that is the observation object. Each image is displayed side by side at the same time. The multiple simultaneous image display can be easily realized by using, for example, a multi-channel image board. In addition, since the upper and lower portions of the image on the oblique surface of the wafer are out-of-focus images (blurred images), three images are simultaneously displayed on the display unit 5 of the Super Extended Graphic Array (SXGA) class by cutting that portion. Can be displayed.

  Operation images for instructing various operations are displayed beside these image display areas. Examples of the operation image include an illumination switching instruction image (button image) 34, a position display image (position display on the wafer) 35, a rotation start instruction image (button image) 36 of the wafer 2, and an image storage instruction image (button image). 37) and a normal / reverse instruction image (button image) 38 of the image. Of course, the operation is not limited to the instruction operation shown in the figure, and an instruction image of a desired operation can be added and displayed, or unnecessary instruction images can be deleted.

  In this example of the instruction image, the observation image is stored by touching the button image 37 of the image storage instruction image when the image to be stored is displayed. Further, by touching the button image 36 of the rotation start instruction image, the rotation of the wafer 2 placed on the rotary table 12 can be controlled. Furthermore, by touching the button image 38 of the forward / reverse instruction image, the rotation of the rotary table 12 can be rotated forward or backward. With the notch provided on the wafer 2 as a reference position, position information (angle, position) of the outer peripheral edge can be displayed.

  As described above, this observation apparatus can also display an image from a low magnification to a high magnification in real time and store an image if the imaging optical system has a zooming mechanism. Position information based on the notch reference of the wafer can be stored together with image information of detected defects, foreign matters, etc., which is useful for failure analysis. Furthermore, by switching the observation illumination direction, the observation performance can be selected when searching for foreign objects and defects, so it is easy to identify the cause of the foreign objects. In addition, since the position sensor detects a change in the observation object and corrects the position, the observation position in the captured image does not change, and a focused image is obtained, so that observation is easy.

  Note that the observation apparatus of the present invention includes three optical modules, each having an image processing unit, and configured to simultaneously display on the display unit, an observation apparatus or end surface defect inspection capable of simultaneously capturing images from three directions. It can also be a device.

  Further, the image signal captured by the imaging unit 3 may be subjected to image processing so that the position processing of the end surface portion displayed on the display unit is made constant by application software stored in the image processing unit 4 in advance. . For example, when the optical module 14 is arranged at the position of the solid line in FIG. 2, the display position of the end face on the display unit is made constant. Even if the wafer 2 is rotated from the image rotation table 12, the alignment accuracy is high and the image is focused with little eccentricity. However, the position of the end face on the display unit 5 is rotated due to the warpage of the wafer 2. When processing that suppresses only fluctuations such as undulations is also performed, the position may be reconstructed and displayed so that the boundary of luminance due to the end face of the image signal is always constant. Further, the relative position between the optical module 14 and the end face of the wafer 2 is detected based on the signals from the position sensors 8 and 9, and the position on the screen is detected based on the detected data. Image processing may be performed so that the image of the end face portion is displayed at a certain position on the display unit based on the positional relationship. In this way, it is possible to observe an image with no positional deviation in real time.

It is a figure which shows schematic structure which looked at the observation apparatus of 1st Embodiment from the normal line direction of the board | substrate. It is the side view which looked at the observation apparatus of 1st Embodiment from the direction orthogonal to the normal line direction of a wafer. It is a figure which shows the structural example of the optical module 14 of the observation apparatus of 1st Embodiment. It is a figure which shows schematic structure which looked at the observation apparatus of 2nd Embodiment from the normal line direction of the board | substrate. It is a figure which shows the example of a screen structure of the image data displayed on a display part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging optical system, 2 ... Observation object (silicon wafer), 3 ... Imaging part, 4 ... Image processing part, 5 ... Display part, 6 ... Movement mechanism, 7 ... Movement mechanism control part, 8, 9 ... Position sensor DESCRIPTION OF SYMBOLS 10 ... Base, 11 ... Control part, 12 ... Rotary table, 13 ... Rotary axis of rotary table, 14 ... Optical module, 21 ... Lens mount main body, 22 ... Objective lens, 23 ... Half mirror, 24 ... Imaging lens, 25: Lens, 26: Light emitting diode (LED), 27: Light shielding cover, 28: Image sensor (CCD).

Claims (11)

An imaging device for imaging the end face of the substrate;
A holding unit that holds the substrate and is rotatable with the normal direction of the substrate as a central axis of rotation;
A displacement detection unit for detecting a variation amount of the position of the end surface portion of the substrate generated by the rotation of the holding unit;
A display unit for displaying an image captured by the imaging device;
A control unit that controls the image of the end face of the substrate imaged by the imaging device based on a signal from the displacement detection unit to be observed at a certain position on the display unit;
An observation apparatus comprising: A moving mechanism for maintaining a constant relative position between the end face of the substrate and the imaging device;
The control unit controls the moving mechanism so as to keep a relative position between the imaging device and the end surface portion of the substrate constant from a detected variation amount of the position of the end surface portion of the substrate. The observation device according to claim 1.   The moving mechanism is an imaging device moving mechanism that allows the imaging device to move in a plane including a central axis of the rotation and an optical axis of the imaging device. The observation apparatus according to claim 2, wherein the image is controlled so that an image of a part is observed at a certain position of the display unit.   The moving mechanism is a holding unit moving mechanism that is movable in a plane including a central axis of the rotation and an optical axis of the imaging load, and the holding unit moving mechanism is configured to image the end face by the control unit. The observation apparatus according to claim 2, wherein the observation device is controlled to be observed at a certain position of the display unit.   The imaging apparatus includes an imaging apparatus moving mechanism that has an optical axis that always passes through a certain point and is rotatable around a certain point in a plane including the rotation axis and the optical axis of the imaging apparatus. The observation device according to any one of claims 1 to 4.   5. The imaging device according to claim 1, wherein a plurality of the imaging devices are provided so that at least two of the end surface of the substrate, the front and back surfaces near the end surface, and the front and back surface removing portions can be observed simultaneously. The observation apparatus according to item.   The observation apparatus according to claim 1, wherein the imaging apparatus includes a moving mechanism of the imaging apparatus that is movable in a direction of the optical axis.   The observation device according to claim 1, wherein the displacement detection unit detects a displacement of an end surface portion of the substrate in a normal direction of the substrate.   The observation apparatus according to claim 1, wherein the displacement detection unit detects a displacement of an end surface portion of the substrate in a direction perpendicular to a normal direction of the substrate.   The control unit detects a relative position between the imaging device and an end surface portion of the substrate based on a signal from the displacement detection unit, and displays an image of the end surface portion at a certain position on the display unit. The observation apparatus according to claim 1, wherein image processing is performed as described above.   An end surface defect inspection apparatus comprising the controller according to claim 1, wherein the control unit has a defect extraction function.

Images