JP2011249657A - Sample absorption retainer and sample absorption determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sample absorption retainer and a sample absorption determination method which can simplify and facilitate the mechanism and control to determine proper absorption of a sample.SOLUTION: A sample absorption retainer 100 comprises: a lift pin 8 to support a sample 6 during carry-in and export; an upthrust pin 10 to thrust up the sample 6 to determine sample absorption; a lift pin driving device 5 to lift the lift pin 8 up and down; and a link mechanism 9 to deliver the lifting driving force of the lift pin 8 to the upthrust pin 10. Further, The link mechanism 9 lifts the upthrust pin 10 to the position where its parietal region thrusts up the sample 6 placed on the top face of a sample stage 4 from the position where it is housed inside the sample stage 4, interlocked with the movement in which the parietal region of the lift pin 8 descends from the position near the top face of the sample stage 4 where it does not protrude to the top face and to the prescribed position of the bottom part of the sample stage 4. After that, the parietal region of the upthrust pin 10 descends to the position where it is housed inside the sample stage 4.

Description

  The present invention relates to a sample adsorption holding device that adsorbs and holds a flat sample such as a semiconductor wafer, and a sample adsorption determination method in the sample adsorption holding device.

  In a process of manufacturing and inspecting a flat substrate such as a semiconductor wafer, a sample adsorption holding device is used to stably hold a substrate to be manufactured and inspected (hereinafter referred to as a sample in this specification). Yes. Sample suction means in the sample suction holding apparatus include an electrostatic chuck using electrostatic attraction and a vacuum suction chuck using a pressure difference of atmospheric pressure.

  The manufacturing / inspection process for semiconductor wafers is highly automated, but if a sample such as a semiconductor wafer to be manufactured / inspected is not normally adsorbed to the sample adsorption / holding device for some reason, the sample is damaged. In addition, there is a risk that the manufacturing / inspection apparatus may be damaged. Therefore, in the sample adsorption holding device, it is indispensable to determine whether or not the sample is normally adsorbed.

  Patent Document 1 discloses a method for detecting a leakage current flowing through an electrode in an electrostatic chuck when a sample is adsorbed as a sample adsorption determination method in a sample adsorption holding device using an electrostatic chuck. According to this method, the sample is placed normally by utilizing the fact that the magnitude of the leakage current differs between when the sample is placed on the electrostatic chuck and when the sample is not placed. It is determined whether or not. This method has an advantage that it is not necessary to add a function in terms of mechanism.

  In Patent Documents 2 and 3, when the sample once placed on the sample adsorption holding device at the time of loading of the sample is lifted by the lift pin used for loading of the sample, the adsorption force and lifting at that time A method is disclosed in which the measured height is measured, and whether or not the sample is normally placed is determined based on the measurement result.

Japanese Patent Laid-Open No. 06-198532 JP 2008-277706 A JP 2005-123422 A

  However, since the leakage current in an electrostatic chuck varies greatly depending on the temperature, the type of sample, the surface state of the electrostatic chuck, etc., whether or not the sample is normally attracted is determined only by the difference in leakage current. Often difficult in practice.

  In the case of a method for measuring the suction force or the height at which the sample is lifted using a lift pin, the lift pin is moved up and down with the sample stably supported when the sample is loaded / unloaded. In addition to the operation described above, it is necessary to add an operation of lifting the sample with a force corresponding to the adsorption force in order to determine the presence or absence of the adsorption force. Since this operation has less overlap with the original operation of the lift pin, a new control mechanism for realizing the operation is required. Therefore, the suction determination method using lift pins has few advantages in terms of simplification of the lift pin control mechanism. The same applies to the case where an adsorption determination pin is provided independently of the lift pin.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, an object of the present invention is to provide a mechanism for determining proper adsorption of a sample, a sample adsorption holding device and a sample adsorption determination method that can simplify and simplify the control thereof. And

  A sample suction holding apparatus according to the present invention includes a lift pin used for loading and unloading a sample, a thrust pin for thrusting a sample for determination of sample suction, a lift pin lifting drive mechanism for lifting and lowering the lift pin up and down, and a lift pin lifting and lowering A link mechanism for transmitting a driving force for raising and lowering the lift pin to the push-up pin, and the link mechanism is configured so that the lift pin raising and lowering drive mechanism projects the lift pin and the top of the sample stage does not protrude from the upper surface of the sample stage. In conjunction with the lowering of the sample stage to a predetermined position below the sample stage, the push-up pin was placed on the upper surface of the sample stage from the position where the top of the pin was stored inside the sample stage. The sample is raised to the position where it is pushed up, and then the top of the sample is lowered to the position where it is stored inside the sample stage. And wherein the are.

  Furthermore, the sample adsorption holding device according to the present invention has a sample proper placement detection sensor for detecting that the sample is properly placed on the sample stage, and controls the operation of the lift pin lifting / lowering drive mechanism. Acquires the output signal from the sample proper placement detection sensor at the timing when the top of the push-up pin pushes up the sample placed on the upper surface of the sample stage, and the obtained signal indicates the proper placement of the sample. When the signal is not indicated, it is determined that the sample is not properly adsorbed on the sample stage.

  As described above, in the sample adsorbing and holding apparatus according to the present invention, a link mechanism having a simple configuration is added to the lift pin lifting / lowering driving mechanism for loading and unloading a sample that has been used conventionally without any particular change. Only the raising and lowering of the push-up pin and the push-up of the sample by the raising and lowering are realized. Further, only by adding a sample proper placement detection sensor that detects that the sample is placed horizontally on the upper surface of the sample stage, the control device can be based on a signal acquired from the sample proper placement detection sensor. It can be determined whether or not the sample is properly adsorbed to the sample stage.

  According to the present invention, a mechanism for determining proper adsorption of a sample, a sample adsorption holding device and a sample adsorption determination method capable of simplifying and simplifying the control thereof are provided.

It is the figure which showed typically the example of the structure of the sample adsorption holding apparatus which concerns on embodiment of this invention. It is the figure which showed typically the perspective view of a lift pin, a thrust pin, and a link mechanism. It is the figure which showed the positional relationship of the two rotation pins of a lift pin, a push-up pin, and a link mechanism at the time of reception of the sample by a lift pin. It is the figure which showed the positional relationship of the two rotation pins of a lift pin, a push-up pin, and a link mechanism at the time of mounting the sample on the electrostatic chuck. It is the figure which showed the positional relationship of the two rotation pins of a lift pin, a thrust pin, and a link mechanism at the time of sample adsorption determination. It is the figure which showed the positional relationship of the two rotation pins of a lift pin, a thrust pin, and a link mechanism at the time of sample proper adsorption being completed. It is the figure which showed the outline of the structure of a push-up pin.

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

  FIG. 1 is a diagram schematically showing an example of the configuration of a sample adsorption holding device according to an embodiment of the present invention. In the example of FIG. 1, the sample suction holding apparatus 100 is housed and used in a sample chamber 1 of an electron microscope, and an electrostatic chuck 7 is used as a suction means.

  As shown in FIG. 1, the main part of the sample adsorption holding device 100 is constituted by a sample stage 4 having a horizontal upper surface, and a thin plate-like electrostatic chuck 7 is fixedly arranged on the upper surface of the sample stage 4. It is installed. The electrostatic chuck 7 is made of a dielectric material, and an electrode plate (not shown) for generating static electricity is provided in the electrostatic chuck 7. Accordingly, when a flat sample 6 such as a semiconductor wafer is placed on the upper surface of the electrostatic chuck 7 and a predetermined voltage is applied to the electrode plate by the power source 12, the surface of the electrostatic chuck 7 and the sample 6 are mutually connected. Static charges with different signs are induced. As a result, the sample 6 is attracted to the upper surface of the electrostatic chuck 7 by the electrostatic attraction. In this embodiment, the electrostatic chuck 7 is regarded as a part of the sample stage 4, and hereinafter, the upper surface of the electrostatic chuck 7 is regarded as the upper surface of the sample stage 4.

  Inside the sample stage 4, a lift pin 8, a push-up pin 10, and a link mechanism 9 that transmits a driving force generated by the operation of the lift pin 8 to the push-up pin 10 are disposed. Details of the lift pin 8, the push-up pin 10, and the link mechanism 9 will be sequentially described in this specification.

  On the other hand, outside the sample stage 4, as other components of the sample adsorption holding device 100, the lift pin driving device 5 that drives the lifting and lowering of the lift pins 8 and the sample 6 are in an appropriate state for the electrostatic chuck 7, ie, the sample stage 4. A sample proper placement detection sensor 11 that detects whether or not the sample is placed, a control device 3 that acquires an output signal from the sample proper placement detection sensor 11 and controls the lift pin driving device 5 and the like, an electrostatic chuck A power supply 12 for applying a voltage to an electrode plate (not shown) in 7 and applying an attracting force to the electrostatic chuck 7 is provided.

  The present embodiment is an embodiment related to an electron microscope to which the sample adsorption holding device 100 is applied. In this case, the sample stage 4 including the electrostatic chuck 7, the lift pin 8, the push-up pin 10 and the link mechanism 9, and The sample proper placement detection sensor 11 is housed in the sample chamber 1 that is always evacuated by a vacuum pump (not shown). Further, an electron microscope body 2 including an electron gun or an electron lens (not shown) is attached to the upper portion of the sample chamber 1, and an electron beam 2a is emitted from the electron microscope body 2. The sample 6 is irradiated.

  Further, a load lock chamber 15 is provided on the right side of the gate valve 1a of the sample chamber 1 in order to maintain a high degree of vacuum in the sample chamber 1 when the sample 6 is loaded / unloaded. Here, the sample chamber 1 and the load lock chamber 15 are isolated by the gate valve 1a. The load lock chamber 15 is also evacuated by a vacuum pump (not shown) and isolated from the atmosphere by a gate valve 15a. A transfer robot (not shown) is arranged inside the load lock chamber 15.

  When the sample 6 is loaded into or unloaded from the sample chamber 1, the gate valve 15a is first opened and the load lock chamber 15 is at atmospheric pressure. At this time, the sample 6 is transferred between the external device and the transfer robot in the load lock chamber 15. Subsequently, the gate valve 15a is closed, the load lock chamber 15 is evacuated, and the gate valve 1a is opened when the degree of vacuum is the same as that of the sample chamber 1.

  This transfer robot has an arm that can be expanded and contracted in the horizontal direction, and can be extended and contracted as appropriate to insert its tip into the sample chamber 1. A flat plate fork-like mounting portion for horizontally mounting and holding the sample 6 is provided at the tip of the arm. Therefore, when the gate valve 1 a is opened, the transfer robot freely moves the arm between the sample chamber 1 and the load lock chamber 15 while holding the sample 6 on the mounting portion.

  The lift pins 8 receive the sample 6 held on the mounting portion of the arm of the transfer robot, place the received sample 6 on the upper surface of the electrostatic chuck 7, and place the sample 6 on the upper surface of the electrostatic chuck 7. This is used when the sample 6 is lifted and delivered to the mounting portion of the arm of the transfer robot. Therefore, the lift pin 8 is configured to be driven by the lift pin driving device 5 so as to protrude from the inside of the sample stage 4 to a position above the upper surface thereof, that is, the upper surface of the electrostatic chuck 7. .

  Here, an outline of the operation of the lift pin 8 at the time of loading / unloading the sample 6 will be described.

  First, the gate valve 1a is opened, and the sample 6 is held by the mounting portion of the arm of the transfer robot and is carried to a position directly above the sample stage 4. Next, the lift pin 8 starts to protrude from the inside of the sample stage 4, and the top of the head rises to a position slightly higher than the placement part of the arm of the transfer robot. At this time, the arm mounting portion has a fork shape that does not interfere with the lifting operation of the lift pin 8. Therefore, when the top of the lift pin 8 rises to a position higher than the placement part of the arm of the transfer robot, the sample 6 is held on the top of the lift pin 8. Note that at least three lift pins 8 are required to hold the flat sample 6.

  Next, the arm of the transfer robot is pulled back to the load lock chamber 15, the gate valve 1 a is closed, and the lift pin 8 is stored inside the sample stage 4 with the sample 6 held at the top of the head. Lower to position. As a result, the sample 6 is placed on the upper surface of the sample stage 4, that is, the electrostatic chuck 7. Thereafter, a predetermined voltage is applied to the electrode plate inside the electrostatic chuck 7, and the sample 6 is attracted to the electrostatic chuck 7.

  The sample 6 is lifted from the sample stage 4 by the lift pins 8 and transferred to the mounting portion of the arm of the transfer robot by the operation opposite to the operation described above, and then is carried out to the load lock chamber 15 by the transfer robot. Is done.

  Next, the configuration and operation of the lift pin 8, the push-up pin 10, and the link mechanism 9 will be described in detail with reference to FIG. 2 in addition to FIG. Here, FIG. 2 is a diagram schematically showing a perspective view of the lift pin 8, the push-up pin 10, and the link mechanism 9.

  As shown in FIGS. 1 and 2, the lift pin 8 is attached to the upper surface of the flat lift pin base 8 b so as to be substantially perpendicular to the upper surface. A spring 8a is provided between the upper surface of the lift pin base 8b and the ceiling part of the sample stage 4, and one end of the spring 8a is fixed to the ceiling part of the sample stage 4, and the other end is the lift pin base. 8b is pressed downward. On the other hand, the drive shaft 5a extending from the lift pin drive device 5 supports the lift pin base 8b from the lower surface side, and when it is driven to extend upward, it resists the pressing force of the spring 8a. The lift pin base 8b is raised. When the downward movement of the drive shaft 5a is driven, the lift pin base 8b is lowered by the pressing force of the spring 8a.

  When the lift pin base 8b is raised, the lift pin 8 is also raised, and when the rise is continued, the top of the lift pin 8 is raised to a position higher than the upper surface of the electrostatic chuck 7. Here, when no attracting force is applied to the electrostatic chuck 7, the sample 6 is held and lifted by the lift pins 8. Note that an opening 7 a is provided in a passage portion where the lift pin 8 of the electrostatic chuck 7 moves up and down, so that the electrostatic chuck 7 does not interfere with the lifting operation of the lift pin 8.

  The drive shaft 5a interferes with the operation when the sample stage 4 is moved in the XYZ directions. In this case, the drive shaft 5a moves backward to a position outside the sample stage 4. . Further, a stopper 8c is provided at a predetermined position below the sample stage 4 to determine the lower limit position of the lift pin base 8b when the drive shaft 5a is retracted to the outside of the sample stage 4 (FIG. 6 and the like which will be described later). reference).

  Next, the link mechanism 9 is fixed to the two gears 9c and 9d rotating in mesh with each other, the shafts 9e and 9f provided on the respective rotation shafts of the gears 9c and 9d, and the shafts 9e and 9f. The rotary pins 9a and 9b are attached and rotate with the rotation of the gears 9c and 9d.

  Here, the rotary pin 9a is urged upward (clockwise in FIG. 1) by a mainspring spring 9h (see FIG. 2) attached to the shaft 9e, and the lift pin base 8b (in FIG. 2, lift pin base). 8b 'provided on the lower surface of the pad portion 8b', which will be described below as not existing). Accordingly, the rotation pin 9a rotates upward (clockwise) as the lift pin 8 rises, and rotates downward (counterclockwise) while the lift pin 8 descends.

  The rotating pin 9b is rotated by the rotational force of the rotating pin 9a transmitted through the gears 9c and 9d and is in contact with the lower surface of the push-up pin base 10b. At this time, the push-up pin 10 is disposed substantially vertically on the upper surface of the push-up pin base 10b. A spring 10a is provided between the upper surface of the push-up pin base 10b and the ceiling portion of the sample stage 4, and one end of the spring 10a is fixed to the ceiling portion of the sample stage 4 and the other end. Presses the upper surface of the push-up pin base 10b downward. Therefore, the push-up pin 10 moves up and down according to the height of the rotation pin 9b.

  As described above, when the lift pin 8 moves up and down, the rotation pin 9a and the rotation pin 9b rotate according to the lifting operation, and as a result, the push-up pin 10 moves up and down. In addition, the further detailed interlocking relationship of the raising / lowering operation | movement of the lift pin 8 and the thrust pin 10 is demonstrated with reference to FIGS. 3-6 separately.

  By the way, when the rotary pin 9b reaches the highest position, the top of the push-up pin 10 passes through the opening 7a provided in the electrostatic chuck 7 and presses the lower surface of the sample 6. At this time, if the pressing force is adjusted to be larger than the weight of the sample 6 and smaller than the standard attraction force of the electrostatic chuck 7 to attract the sample 6, the sample 6 is lifted by the push-up pin 10. Whether or not the sample 6 is properly attracted to the electrostatic chuck 7 can be determined by detecting whether or not the sample is absorbed. That is, when the sample 6 is lifted by the push-up pin 10, the sample 6 is not properly attracted to the electrostatic chuck 7, and the sample 6 is not lifted by the push-up pin 10. In this case, the sample 6 is properly attracted to the electrostatic chuck 7.

  The standard attracting force referred to here is an attracting force obtained on average when a predetermined voltage is applied to the electrode plate of the electrostatic chuck 7 and the sample 6 is properly attracted to the electrostatic chuck 7. It is assumed that the adsorption force is sufficiently smaller than that. In addition, the standard adsorption force is obtained in advance through experiments and the like, and the weight of the sample 6 itself is added to the standard adsorption force for convenience.

  A spring 10 c is built in the upper part of the push-up pin 10. As a result, the pressing force with which the push-up pin 10 presses the lower surface of the sample 6 is easily adjusted by changing the length and the elastic coefficient of the spring 10c (in practice, by replacing with another spring having a different elastic coefficient). be able to. The structure of the push-up pin 10 will be described later (see FIG. 7).

  In FIG. 1, a sample proper placement detection sensor 11 is a sensor that determines whether or not the sample 6 is properly placed on the electrostatic chuck 7. For example, the distance to the sample 6 is within a predetermined distance. Or whether the surface of the sample 6 is kept horizontal. When the sample 6 is not placed at a position within a predetermined distance range or the surface of the sample 6 is not kept horizontal, the sample proper placement detection sensor 11 determines that the sample 6 is appropriate. Is output to the control device 3.

  Such a sample proper placement detection sensor 11 can be easily realized by a laser interferometer or the like, but more simply, for example, as shown in FIG. 1, a light emitting unit 11 a configured by a light emitting element. It can also be realized by a sensor including a light receiving portion 11b composed of a light receiving element. Incidentally, in the simple sample proper placement detection sensor 11, convergent light is emitted from the light emitting unit 11 a to the surface of the sample 6 so as to form a predetermined inclination angle with the surface, and depending on the surface of the sample 6. It is determined whether or not the reflected light can be received by the light receiving unit 11b provided at a predetermined position.

  In the configuration of the lift pin 8, the push-up pin 10 and the link mechanism 9 described above, the lift pin 8 and the push-up pin 10 have a small friction with the sample 6 because the tops thereof are in contact with the sample 6. It is preferable to use a material that does not easily generate foreign matter. As such a resin, for example, a PEEK (polyether ether ketone) resin that has high wear resistance and emits a small amount of gas in a vacuum is suitable. Similarly, the heads of the rotary pins 9a and 9b of the link mechanism 9 are preferably formed of the same resin.

  Next, referring to FIG. 3 to FIG. 6, after the lift pin 8 receives the sample 6 from the transfer robot in the load lock chamber 15, the lift pins 8 and the push-up pins 10 are moved up and down in the process of lowering. The relationship and the operation of the link mechanism 9 will be described in detail. Here, FIG. 3 is a diagram showing the positional relationship between the lift pin 8, the push-up pin 10 and the rotation pins 9 a and 9 b of the link mechanism 9 when the sample 6 is received by the lift pin 8, and FIG. FIG. 5 is a diagram showing the positional relationship between the lift pin 8, the push-up pin 10 and the rotation pins 9a and 9b of the link mechanism 9 when placed on the chuck 7. FIG. 5 shows the lift pin 8 and the push-up pin 10 at the time of sample adsorption determination. FIG. 6 shows the positional relationship between the rotation pins 9a and 9b of the link mechanism 9, and FIG. 6 shows the positional relationship between the lift pin 8, the push-up pin 10 and the rotation pins 9a and 9b of the link mechanism 9 when the sample is properly adsorbed. It is a figure.

  As shown in FIG. 3, when the lift pin 8 is pushed up by the drive shaft 5 a of the lift pin driving device 5 and receives the sample 6 from the arm of the transfer robot, the lift pin 8 is moved upward from the upper surface of the electrostatic chuck 7. It protrudes to the highest position where it can be lifted. At this time, the rotation pin 9a is urged by the mainspring spring 9h, rotates upward, and its rotation is restricted by the stopper 9g. Therefore, the top of the rotary pin 9a is located away from the lower surface of the lift pin base 8b.

  At this time, the length of the rotation pin 9b and the rotation angle of the gear 9d are adjusted in advance so that the top of the rotation pin 9b comes into contact with the left end of the lower surface of the push-up pin base 10b. The length and the like of the raising pin 10 are adjusted so that the top of the raising pin 10 does not protrude outside the upper surface of the electrostatic chuck 7.

  Next, as shown in FIG. 4, when the drive shaft 5a is retracted downward, the lift pin base 8b is pressed by the spring 8a and descends together with the drive shaft 5a. Therefore, the lift pin 8 is also lowered, and the sample 6 is placed on the upper surface of the electrostatic chuck 7 when the top of the lift pin 8 reaches below the upper surface of the electrostatic chuck 7 and near the upper surface. Only at this time, the lengths of the lift pins 8 and the rotation pins 9a and the positions of the stoppers 9g are determined in advance so that the top of the rotation pins 9a contacts the lower surface of the lift pin base 8b. Therefore, even if the lift pin 8 is lowered from the position shown in FIG. 3 to the position shown in FIG. 4, the rotary pin 9a does not rotate in particular, and the push-up pin 10 does not move up or down in particular. .

  On the other hand, at this time, the control device 3 controls the power supply 12 to apply a predetermined voltage to the internal electrode plate of the electrostatic chuck 7. As a result, static electricity is induced on the surface of the electrostatic chuck 7 and the sample 6, and the sample 6 is attracted to the electrostatic chuck 7.

  Next, as shown in FIG. 5, when the drive shaft 5a is further retracted downward, the lift pin base 8b is pressed by the spring 8a and descends together with the drive shaft 5a. At this time, the rotation pin 9a is pressed by the lift pin base 8b and rotates downward (to the left). The rotational force is transmitted as the rotational force of the rotation pin 9b via the gears 9c and 9d. As a result, the rotation pin 9b rotates rightward, and the push-up pin 10 is pushed up by the rotation pin 9b. When the rotary pin 9b faces vertically upward, the top of the push-up pin 10 rises to the highest position.

  At this time, the top of the push-up pin 10 presses the lower surface of the sample 6. As described above, the pressing force is larger than the weight of the sample 6, and the electrostatic chuck 7 attracts the sample 6. It is set to be smaller than the attraction force. Therefore, when the sample 6 is not properly attracted to the electrostatic chuck 7, the push-up pin 10 side of the sample 6 is lifted away from the electrostatic chuck 7 as shown in FIG. 5.

  In that case, the sample 6 is not parallel to the upper surface of the electrostatic chuck 7 but is supported with a slight inclination. Therefore, the sample proper placement detection sensor 11 detects that the sample 6 is lifted by detecting that the distance to the sample 6 is different or that the surface of the sample 6 is tilted. It detects that it is not properly adsorbed, and outputs the detection signal to the control device 3. On the other hand, even when the sample 6 is pressed by the top of the push-up pin 10, if it remains adsorbed by the electrostatic chuck 7, the sample proper placement detection sensor 11 indicates that the sample 6 is adsorbed properly. Is output to the control device 3.

  As described above, in the operation process so far, the control device 3 can determine whether or not the sample 6 is properly attracted to the electrostatic chuck 7. Therefore, when it is determined that the sample 6 is not properly attracted to the electrostatic chuck 7, the control device 3 can thereafter execute various corresponding processes. For example, the control device 3 may immediately stop the operation of the lift pin driving device 5 and notify the sample operator of the abnormal adsorption of the sample via an alarm device or a display device (not shown). Thus, the adsorption may be retried.

  In order to retry adsorption, the control device 3 controls the lift pin drive device 5 to drive the drive shaft 5a that has been retracted upward, so that the lift pin 8 of the lift pin 8 shown in FIG. Return to position (raise). Further, by controlling the power source 12 to increase the voltage applied to the electrode plate in the electrostatic chuck 7 by a predetermined amount, the attracting force is enhanced. Therefore, the power source 12 and the control device 3 that controls the power source 12 correspond to the suction force increasing means.

  Furthermore, the control device 3 controls the lift pin drive device 5 to retreat the drive shaft 5a and lower the lift pin 8, thereby reproducing the state of FIG. 5 and whether the sample 6 is properly adsorbed again. Determine whether or not

  As a result of the determination, when it is determined that the sample 6 is properly attracted to the electrostatic chuck 7, the control device 3 holds the sample with the increased attracting force on the electrostatic chuck 7, Proceed to the next step. Further, if the sample 6 is not properly attracted to the electrostatic chuck 7 even if the same retry is performed a predetermined number of times while controlling the power source 12 and increasing the attracting force, an alarm device (not shown) is used. The operator of the process is informed of the abnormal adsorption of the sample by using a display device.

  When the sample 6 is properly attracted to the electrostatic chuck 7 and the proper adsorption is confirmed by the control device 3, the drive shaft 5a is pulled out from the sample stage 4 as shown in FIG. It is stored in the drive device 5. The sample stage 4 can freely move in the XYZ direction in the sample chamber 1.

  In this case, the lift pin base 8b is pressed by the spring 8a and descends further downward than the position shown in FIG. 5, but its lower limit position is restricted by the stopper 8c. Accordingly, the rotation pin 9a is also pressed by the lift pin base 8b and rotates downward, but its lower limit position is restricted by the lower limit position of the lift pin base 8b.

  Further, the rotation pin 9b rotates in the right direction as the rotation pin 9a rotates downward. As a result, the push-up pin 10 descends, and its top is below the upper surface of the electrostatic chuck 7. Lower to position.

  The procedure for transferring the sample 6 adsorbed on the electrostatic chuck 7 to the transfer robot is described with reference to FIGS. 3 to 6 after cutting off the voltage applied to the electrode plate in the electrostatic chuck 7. The procedure can be reversed. However, in this case, the control device 3 does not need to determine whether or not the sample 6 is adsorbed even when the push-up pin 10 pushes up the sample 6 (see FIG. 5).

  As described above with reference to FIGS. 3 to 6, the sample 6 is received from the transfer robot (see FIG. 3), the lift pin 8 is lowered, and the sample 6 is placed on the upper surface of the electrostatic chuck 7. In the operation of attracting the electrostatic chuck 7 (see FIGS. 4 and 5) and removing the drive shaft 5a of the lift pin driving device 5 from the sample stage 4 (see FIG. 6), the sample 6 is placed on the upper surface of the electrostatic chuck 7. It is an operation that is always carried out when it is placed and attracted to the electrostatic chuck 7.

  In the present embodiment, the link mechanism 9 transmits the driving force of the operation in which the lift pin 8 is lowered in the operation that is necessarily performed to the push-up pin 10 and causes the push-up pin 10 to push up the sample 6. ing. That is, in the present embodiment, no special driving device is provided except for the link mechanism 9 in order to drive the push-up pin 10. Such a link mechanism 9 can be realized in a narrow space with a simple structure. Moreover, the burden on the control device 3 does not increase due to the drive of the link mechanism 9.

  As described above, according to the present embodiment, it is possible to cause the push-up pin 10 to push up the sample 6 simply by adding the link mechanism 9 having a simple structure, and the burden on the control device 3 is reduced. Does not increase. Therefore, the control mechanism and control procedure of the lift pin 8 and the push-up pin 10 can be simplified and simplified as compared with the prior art.

  Finally, with reference to FIG. 7, the structure of the push-up pin 10 will be supplemented. FIG. 7 is a diagram showing an outline of the structure of the push-up pin. As shown in FIG. 7A, the push-up pin 10 includes a pin base portion 10d and a sample holding portion 10f, and a sheath portion 10e having a sheath structure is formed on the top of the pin base portion 10d. . And the lower part of the sample holding | maintenance part 10f and the spring 10c are accommodated in the sheath part 10e.

  Here, when the push-up pin 10, that is, the pin base portion 10 d rises, and the sample holding portion 10 f presses the lower surface of the sample 6 attracted to the electrostatic chuck 7, the pressing force is the spring It is determined by the elastic constant of 10c and the compression amount. Therefore, the pressing force with which the push-up pin 10 presses the sample 6 can be easily adjusted by replacing the spring 10c with another spring having a different elastic constant or changing the length of the sample holding portion 10f. Can do. In this case, as described above, the pressing force is set so as to be larger than the weight of the sample 6 and smaller than the standard attracting force with which the electrostatic chuck 7 attracts the sample 6.

  When the suction force of the sample 6 attracted to the electrostatic chuck 7 is larger than the pressing force of the push-up pin 10, the sample 6 remains in the state of being attracted by the electrostatic chuck 7, and FIG. ), The spring 10c is compressed, and the sample holding portion 10f is recessed downward. Further, when the attracting force of the sample 6 attracted to the electrostatic chuck 7 is smaller than the pressing force of the thrust pin 10, the thrust pin 10 is placed on the upper surface of the electrostatic chuck 7 as shown in FIG. Thus, a part of the sample 6 is lifted above the electrostatic chuck 7.

  Further, in the push-up pin 10 having such a structure, even when the push-up pin 10 reaches the lower limit position, the top of the sample holder 10f is positioned slightly above the upper surface of the electrostatic chuck 7. It can be adjusted to be positioned. In that case, when the sample 6 is attracted to the electrostatic chuck 7, the top of the sample holding portion 10f comes into contact with the lower surface of the sample 6 with a slight force. Therefore, in this case, for example, if the push-up pin 10 is grounded, the push-up pin 10 is used as an electrode for discharging the electric charge charged more than necessary on the sample 6 and stabilizing the potential. Can do. In the electron microscope, it is known that the image quality of the observation image of the obtained sample is improved when the potential on the surface of the sample 6 is stabilized.

(Other embodiments)
In the above-described embodiment, the sample suction holding apparatus 100 using the electrostatic chuck 7 has been described. However, most of the description can be applied to a sample suction holding apparatus using a vacuum suction chuck. The electrostatic chuck 7 is not provided with the electrostatic chuck 7, and instead, a thin groove or the like is formed on the upper surface of the sample stage 4, and a suction force is obtained by vacuum-sucking the groove. The vacuum suction chuck cannot be applied to a sample suction holding device used in a vacuum sample chamber such as an electron microscope. However, there are many sample adsorbing and holding devices used in an atmospheric pressure environment such as various semiconductor inspection devices.

  Further, the main feature of the above-described embodiment is that the link mechanism 9 and the driving force of the lift pin 8 are transmitted to the push-up pin 10 by the link mechanism 9 to cause the push-up pin 10 to push up the sample 6. However, this feature can be applied in the same manner even when the suction means is changed from the electrostatic chuck to the vacuum suction chuck in the sample suction holding apparatus. Therefore, the same effect as that of the above-described embodiment can be obtained even with the sample suction holding apparatus using the vacuum suction chuck.

  In the case of the electrostatic chuck 7, the suction force can be controlled by the voltage applied to the electrode plate in the electrostatic chuck 7. In the case of the vacuum suction chuck, the suction force of the vacuum pump that performs vacuum suction is controlled. It can be controlled by suction force.

DESCRIPTION OF SYMBOLS 1 Sample chamber 1a, 15a Gate valve 2 Electron microscope mirror body 2a Electron beam 3 Control apparatus 4 Sample stage 5 Lift pin drive device 5a Drive shaft 6 Sample 7 Electrostatic chuck (adsorption means)
7a Opening 8 Lift pin 8a Spring (spring mechanism)
8b Lift pin base 8b 'Pad part 8c Stopper 9 Link mechanism 9a, 9b Rotating pin 9c, 9d Gear 9e, 9f Shaft 9g Stopper 9h Spring spring 10 Push-up pin 10a, 10c Spring 10b Pin base 10d Pin base part 10e Sheath part 10e Holding unit 11 Specimen proper placement detection sensor 11a Light emitting unit 11b Light receiving unit 12 Power supply (adsorption force increasing means)
15 Load lock chamber 100 Sample adsorption holding device

Claims (9)

A sample stage having an adsorption means disposed on the upper surface, and adsorbing and holding the sample on the upper surface via the adsorption means;
A lift pin that is arranged inside the sample stage, protrudes from the inside of the sample stage to the outside of the upper surface thereof, and supports the sample substantially horizontally;
A push-up pin that is disposed inside the sample stage and pushes the sample held on the sample stage from the inside of the sample stage to the outside of the upper surface;
A lift pin raising / lowering drive mechanism for raising and lowering the lift pin up and down;
A link mechanism for transmitting a driving force by which the lift pin lifting drive mechanism lifts and lowers the lift pin to the push-up pin;
A sample adsorption holding device comprising:
The link mechanism is
When the lift pin raising / lowering drive mechanism lowers the lift pin from a position near the upper surface where the top of the sample does not protrude from the upper surface of the sample stage to a predetermined position below the sample stage, the lift pin is interlocked with the operation. Then, the push-up pin is raised from the position where the top of the push-up pin is housed inside the sample stage to the position where the sample placed on the upper surface of the sample stage is pushed up, A sample adsorbing and holding apparatus, wherein the top of the head is lowered to a position accommodated in the sample stage. A sample proper placement detection sensor for detecting that the sample is placed horizontally on the upper surface of the sample stage;
A control device that controls the operation of the lift pin lifting and lowering drive mechanism and determines whether or not the sample is properly adsorbed on the sample stage based on a signal output from the sample proper placement detection sensor;
Further comprising
The controller is
When the lift pin lifting and lowering drive mechanism is controlled and the lift pin is lowered from a position in the vicinity of the upper surface where the top of the sample does not protrude from the upper surface of the sample stage to a predetermined position below the sample stage,
The push-up pin operates in conjunction with the operation of the lift pin via the link mechanism, and the top of the push-up pin pushes up the sample placed on the upper surface of the sample stage, A signal output from the sample proper placement detection sensor is acquired, and when the acquired signal is not a signal indicating proper placement of the sample, it is determined that the sample is not properly adsorbed on the sample stage. The sample adsorbing / holding device according to claim 1. Further comprising an adsorption force enhancing means for enhancing the adsorption force of the adsorption means,
The controller is
Based on the signal output from the sample proper placement detection sensor, if it is determined that the sample is not properly adsorbed to the sample stage,
After controlling the adsorption force enhancing means to increase the adsorption force of the adsorption means,
The lift pin lifting / lowering drive mechanism is controlled to raise the lift pin to a position near the upper surface where the top of the sample does not protrude from the upper surface of the sample stage, and again from that position to a predetermined position below the sample stage. Down to
At the timing when the top of the push-up pin pushes up the sample placed on the upper surface of the sample stage, the signal output from the sample detection sensor is acquired again, and based on the acquired signal, the sample is It is determined again whether it is adsorb | sucking appropriately by the said sample stage. The sample adsorption holding device of Claim 2 characterized by these. The lift pin elevating drive mechanism is
A lift pin driving device that lifts the lift pin by pressing a flat plate-like pedestal disposed on the upper surface side of the lift pin substantially perpendicularly to the upper surface;
A spring mechanism disposed between the ceiling of the sample stage and the pedestal and pressing the pedestal downward;
The sample adsorbing / holding device according to claim 1, wherein the sample adsorbing / holding device is provided. 5. The spring according to claim 1, wherein the push-up pin incorporates a spring mechanism that adjusts a pressing force when the push-up pin pushes up the sample. Sample adsorption holding device. The sample suction holding apparatus according to any one of claims 1 to 5, wherein the suction means is an electrostatic chuck. The sample suction holding apparatus according to any one of claims 1 to 5, wherein the suction means is a vacuum suction chuck. A sample stage having an adsorption means disposed on the upper surface, and adsorbing and holding the sample on the upper surface via the adsorption means;
A lift pin that is arranged inside the sample stage, protrudes from the inside of the sample stage to the outside of the upper surface thereof, and supports the sample substantially horizontally;
A push-up pin that is disposed inside the sample stage and pushes the sample held on the sample stage from the inside of the sample stage to the outside of the upper surface;
A lift pin raising / lowering drive mechanism for raising and lowering the lift pin up and down;
A link mechanism for transmitting a driving force by which the lift pin lifting drive mechanism lifts and lowers the lift pin to the push-up pin;
A sample proper placement detection sensor for detecting that the sample is placed horizontally on the upper surface of the sample stage;
A control device that controls the operation of the lift pin lifting and lowering drive mechanism and determines whether or not the sample is properly adsorbed on the sample stage based on a signal output from the sample proper placement detection sensor;
A sample adsorption determination method in a sample adsorption holding device comprising:
The link mechanism is
When the lift pin raising / lowering drive mechanism lowers the lift pin from a position near the upper surface where the top of the sample does not protrude from the upper surface of the sample stage to a predetermined position below the sample stage, the lift pin is interlocked with the operation. Then, the push-up pin is raised from the position where the top of the push-up pin is housed inside the sample stage to the position where the sample placed on the upper surface of the sample stage is pushed up, The top of the head is configured to be lowered to a position accommodated inside the sample stage,
The controller is
When the lift pin lifting and lowering drive mechanism is controlled and the lift pin is lowered from a position in the vicinity of the upper surface where the top of the sample does not protrude from the upper surface of the sample stage to a predetermined position below the sample stage,
The push-up pin operates in conjunction with the operation of the lift pin via the link mechanism, and the top of the push-up pin pushes up the sample placed on the upper surface of the sample stage, A signal output from the sample proper placement detection sensor is acquired, and when the acquired signal is not a signal indicating proper placement of the sample, it is determined that the sample is not properly adsorbed on the sample stage. A method for determining sample adsorption. Further comprising an adsorption force enhancing means for enhancing the adsorption force of the adsorption means,
The controller is
Based on the signal output from the sample proper placement detection sensor, if it is determined that the sample is not properly adsorbed to the sample stage,
After controlling the adsorption force enhancing means to increase the adsorption force of the adsorption means,
The lift pin lifting / lowering drive mechanism is controlled to raise the lift pin to a position near the upper surface where the top of the sample does not protrude from the upper surface of the sample stage, and again from that position to a predetermined position below the sample stage. Down to
At the timing when the top of the push-up pin pushes up the sample placed on the upper surface of the sample stage, the signal output from the sample detection sensor is acquired again, and based on the acquired signal, the sample is The sample adsorption determination method according to claim 8, wherein it is determined again whether or not the sample stage is properly adsorbed.

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