JP5547044B2 - Inspection method and inspection apparatus - Google Patents

Description

  The present invention relates to an inspection apparatus suitable for use in semiconductor manufacturing and inspection processes, and more particularly to an inspection method and an inspection apparatus provided with a vacuum robot for transporting a sample.

  Some charged particle devices typified by a scanning electron microscope include a load lock chamber connected to a vacuum chamber serving as a sample chamber. The load lock chamber is a preliminary evacuation chamber for placing a sample in advance before introducing the sample into the sample chamber. In general, a sample is transported from the load lock chamber to the sample chamber by the sample holder in which the sample is set.

  However, the method of transporting the entire sample holder has disadvantages such as a complicated transport mechanism and a large internal volume due to the mounting of the transport mechanism, which takes time to exhaust. Therefore, a method in which the sample holder is omitted and the sample is directly transferred by a vacuum robot is used.

  In the transport of the sample by the vacuum robot, a positional shift due to the transport occurs. That is, an error occurs between the target position designated in advance and the position where the sample is actually arranged. In order to solve this problem, in the methods described in Patent Documents 1 to 3, a correction table is created from a preset designated position and an actual installation position, and the designated position of the robot is corrected.

JP 2009-49251 JP 2010-56161 A JP 2008-251968

  In transporting a sample by a vacuum robot, it is not possible to completely eliminate the positional deviation of the sample. In particular, since the vacuum robot is installed in an evacuated atmosphere, it is necessary to simplify the structure as much as possible. It is not preferable to provide the vacuum robot with a complicated position correction mechanism such as the position correction mechanism described in the patent document.

  An object of the present invention is to provide an inspection apparatus provided with a simple mechanism for correcting a positional deviation when a sample is conveyed by a vacuum robot.

According to the present invention, first, the load position (X _L , Y _L ) and unload position (X _U , Y _U ) of the sample stage and the rotation angle (θ _L ) of the pre-aligner are stored. Pre-alignment is performed in which the wafer on the pre-aligner is rotated by a rotation angle (θ _L ) with respect to the reference orientation, and the eccentric amount (Δx ₁ , Δy ₁ ) of the wafer with respect to the pre-aligner is measured. The load position (X _L , Y _L ) of the sample stage is corrected based on the eccentric amount (Δx ₁ , Δy ₁ ).

According to the present invention, global alignment is performed to measure the positional deviation amount and rotational deviation amount (ΔX ₁ , ΔY ₁ , Δθ ₁ ) of the wafer on the sample stage. The load position (X _L , Y _L ) and the rotation angle (θ _L ) for the next wafer for inspection are corrected using the wafer positional deviation amount and rotational deviation amount.

  According to the present invention, there is provided an inspection apparatus having a simple mechanism for correcting a positional deviation when a sample is conveyed by a vacuum robot.

It is a figure which shows the structure of the 1st example of the test | inspection apparatus of this invention. It is a figure explaining the structure and operation | movement of a vacuum robot provided in the inspection apparatus of this invention. It is a figure explaining the structure and operation | movement of a vacuum robot provided in the inspection apparatus of this invention. It is a figure explaining the structure and operation | movement of a vacuum robot provided in the inspection apparatus of this invention. It is a figure explaining the loading process of the wafer by the test | inspection apparatus of this invention. Wafer eccentricity by the inspection apparatus of the present invention (Δx _1, Δy ₁₎ is a diagram showing data accumulated. It is a figure explaining the inspection and unload process of a wafer by the inspection device of the present invention. It is a figure which shows the structure of the 2nd example of the test | inspection apparatus of this invention. It is a figure which shows the structure of the 3rd example of the test | inspection apparatus of this invention.

  A first example of the inspection apparatus of the present invention will be described with reference to FIG. The inspection apparatus of this example includes a sample chamber 101, a load lock chamber 107, and a mini-environment transfer device 110, and further includes a control device (not shown). The control device may be a computer that includes an input device, an output or display device, and a computing device. Here, a wafer will be described as an example of an inspection object by the inspection apparatus.

  Conventionally, in a manufacturing process of a semiconductor integrated circuit, a clean room has been used in order to avoid generation of dust and foreign matter. However, in recent years, a clean environment maintenance method called a mini environment method has been used instead of a clean room. In the mini-environment method, a high cleanliness is locally maintained only in a space where cleanness is required.

  In the manufacturing process of a semiconductor integrated circuit, a single wafer processing is often performed for each wafer, photomask, or the like to be inspected. Therefore, wafers, photomasks, etc. are often transferred one by one. Known as mini-environment containers for storing one wafer and photomask are SMIF POD (Standard of Mechanical Interface Pod) and Hoop (FOUP) (Front-Opening Unified Pod). Yes. Sumif pods and hoops are sealed containers whose interior is kept at a high degree of cleanliness.

  In the sample chamber 101, a scanning electron microscope 102, an optical microscope 103, a sample stage 106, and a vacuum robot 104 are provided. The sample stage 106 is provided with an electrostatic chuck 105. The sample stage 106 can move in the XY directions and rotate. A pre-aligner 108 is provided in the load lock chamber 107. Further, a measuring device (not shown) for measuring the amount of eccentricity of the wafer on the pre-aligner 108 is provided. The transfer device 110 is provided with a transfer robot 109. A load port 111 is provided outside the transfer device 110, and a hoop 112 is disposed there. The inside of the hoop 112 is maintained with high cleanliness, and a single wafer 10 is accommodated therein. A smif pod may be used instead of the hoop.

  The load lock chamber 107 is a preliminary vacuum exhaust chamber. The load lock chamber 107 is evacuated when connected to the sample chamber 101, and becomes atmospheric pressure when connected to the transfer device 110.

  The transfer robot 109 takes out the wafer 10 from the hoop 112 and places it on the pre-aligner 108. In the pre-aligner 108, pre-alignment is executed.

The pre-alignment is a process of rotating the wafer 10 so that the rotation position of the wafer 10 becomes a predetermined rotation position. Marks are formed on the periphery of the wafer 10. This mark may be a notch, for example. On the other hand, a mark is attached to the periphery of the table of the pre-aligner 108. The wafer 10 is placed on the table of the pre-aligner 108 and rotated. When the mark on the wafer 10 is aligned with the mark on the pre-aligner 108, the rotation of the pre-aligner 108 is stopped. The rotation position of the wafer 10 at this time is referred to as a reference orientation. In the pre-alignment, the wafer 10 is further rotated from the reference orientation by a predetermined pre-aligner rotation angle (θ _L ), which will be described later.

  The vacuum robot 104 loads the wafer 10A disposed on the pre-aligner 108 onto the sample stage 106, and unloads the wafer 10B disposed on the sample stage 106 onto the pre-aligner 108. The transfer robot 109 unloads the wafer on the pre-aligner 108 into the hoop 112.

  The structure and operation of the vacuum robot 104 will be described with reference to FIGS. 2A, 2B, and 2C. The vacuum robot 104 includes a main arm 201, a load hand 202, and an unload hand 203. The main arm 201 is rotatable around a vertical central axis. A load hand 202 and an unload hand 203 are pivotally attached to both ends of the main arm 201, respectively.

  As shown in FIG. 2A, the wafer 10A on the pre-aligner 108 is lifted by the load hand 202, and the wafer 10B on the sample stage 106 is lifted by the unload hand 203. Next, as shown in FIG. 2B, the load hand 202 and the unload hand 203 are pivoted and the main arm 201 is rotated. Further, as shown in FIG. 2C, the main arm 201 is rotated and the load hand 202 and the unload hand 203 are pivoted. The wafer 10A on the load hand 202 is moved onto the sample stage 106, and the wafer 10B on the unload hand 203 is moved onto the pre-aligner 108.

Reference is again made to FIG. Before carrying the wafer, the load position (X _L , Y _L ) and unload position (X _U , Y _U ) of the sample stage 106 and the rotation angle (θ _L ) is saved.

It is assumed that the wafer 10 is arranged at the center position of the pre-aligner 108, that is, the eccentric amount of the wafer 10 on the pre-aligner 108 is zero. In this state, it is assumed that when the wafer is transferred onto the sample stage 106 by the load hand 202 of the vacuum robot 104, the wafer is placed at the center position on the sample stage 106. The stage position of the sample stage 106 at this time is set as the load position (X _L , Y _L ).

Assume that when the wafer 10 mounted at the center position on the sample stage 106 is transferred to the pre-aligner 108 by the unload hand 203 of the vacuum robot 104, the wafer is placed at the center position of the table of the pre-aligner 108. The stage position of the sample stage 106 at this time is set as an unload position (X _U , Y _U ).

The deviation between the load position (X _L , Y _L ) and the unload position (X _U , Y _U ) is due to the difference in the shape and mounting position of the load hand 202 and the unload hand 203.

  When the wafer 10 is transferred from the pre-aligner 108 onto the sample stage 106 by the vacuum robot 104, the wafer substantially rotates due to the pivotal movement of the main arm 201 and the load hand 202. As described above, the rotation position of the wafer 10 is arranged in the reference orientation by pre-alignment. At this time, it is assumed that the arrangement pattern of the wafers arranged on the pre-aligner 108 is arranged along the x direction. In this state, when the wafer 10 is transferred from the pre-aligner 108 onto the sample stage 106 by the vacuum robot 104, the arrangement pattern of the wafers arranged on the sample stage 106 is not arranged in the X direction due to the rotation of the wafer 10. In this case, in order for the arrangement pattern of the wafers arranged on the sample stage 106 to be arranged in the X direction of the sample stage, it is necessary to rotate the wafer arranged on the pre-aligner 108 by a predetermined angle in advance.

Therefore, it is assumed that the wafer placed on the pre-aligner 108 is further rotated with respect to the reference orientation. In this state, it is assumed that when the wafer 10 is transferred from the pre-aligner 108 onto the sample stage 106 by the vacuum robot 104, the arrangement pattern of the wafers 10 on the sample stage 106 is arranged along the X direction. The rotation angle with respect to the reference orientation of the wafer on the pre-aligner 108 at this time is set as the rotation angle (θ _L ) of the pre-aligner. The rotation angle (θ _L ) represents the rotation of the wafer due to the transfer of the wafer 10 by the vacuum robot 104.

According to the present invention, the set values of the load position (X _L , Y _L ), unload position (X _U , Y _U ), and rotation angle (θ _L ) are corrected for each inspection.

  With reference to FIG. 3, a method for transporting the wafer onto the sample stage 106 in the sample chamber 101 will be described. In this example, the position error caused by the transfer by the transfer robot 109 is eliminated by correcting the load position of the sample stage 106.

First, in step S201, the wafer 10 stored in the FOUP 112 is taken out by the transfer robot 109 of the transfer apparatus 110. In step S202, the wafer 10 is transferred onto the pre-aligner 108 of the load lock chamber 107 by the transfer robot 109 of the transfer apparatus 110. In step S203, the load lock chamber 107 is evacuated, and the pre-alignment of the wafer 10 is performed by the pre-aligner 108. By the pre-alignment, the rotation position of the wafer 10 is a position rotated by the rotation angle (θ _L ) of the pre-aligner with respect to the reference orientation. The pre-alignment adjusts the rotational position of the wafer 10 on the pre-aligner 108, and the position error of the wafer 10 with respect to the pre-aligner 108 in the x direction or the y direction cannot be corrected.

In step S204, the amount of eccentricity (Δx ₁ , Δy ₁ ) of the wafer on the pre-aligner 108 is measured. The amount of wafer eccentricity is the deviation between the center of the wafer and the center of the pre-aligner table 108. This eccentric amount is caused by the transfer of the transfer robot 109.

In step S205, the load position (X _L , Y _L ) is corrected based on the wafer eccentricity (Δx ₁ , Δy ₁ ). The corrected load position is (X _L + ΔX _L , Y _L + ΔY _L ). However, ΔX _L and ΔY _L are correction amounts represented by the following Equation 1.
ΔX _L = Δx ₁ cosθ _L + Δy ₁ sinθ _L Formula 1
ΔY _L = -Δx ₁ sinθ _L + Δy ₁ cosθ _L

In step S206, the sample stage 106 is moved to the corrected load position. Finally, in step S207, the wafer 10 on the pre-aligner 108 is transferred to the sample stage 106 by the vacuum robot 104. According to this example, the position error caused by the transfer of the transfer robot 109 is eliminated by correcting the load position (X _L , Y _L ) of the sample stage 106.

FIG. 4 is a graph plotting the amount of eccentricity of the wafer after pre-alignment detected in step S204. The horizontal axis represents the amount of eccentricity Δx ₁ in the x direction, and the vertical axis represents the amount of eccentricity Δy ₁ in the y direction. Each plot shows the amount of eccentricity of the wafer on the pre-aligner 108 for each transfer. The amount of eccentricity of the wafer represents a position error caused by the transfer by the transfer robot 109. Possible causes of the position error include a decrease in the transfer accuracy of the transfer robot 109 and a position shift between the transfer device 110 and the load lock chamber 107. In the former case, the amount of eccentricity (Δx ₁ , Δy ₁ ) appears randomly for each conveyance. In the latter case, the eccentricity (Δx ₁ , Δy ₁ ) changes along a straight line as indicated by reference numeral 503. That is, the amount of eccentricity tends to increase along a certain direction. This is because the positional deviation between the transfer device 110 and the load lock chamber 107 increases with time. Therefore, when the eccentricity (Δx ₁ , Δy ₁ ) changes linearly, it can be determined that a positional deviation has occurred between the transfer device 110 and the load lock chamber 107. In such a case, an alarm may be generated or displayed to warn that there is a possibility that a positional deviation has occurred between the transfer device 110 and the load lock chamber 107.

An alarm may be generated when the amount of eccentricity (Δx ₁ , Δy ₁ ) exceeds a predetermined magnitude. For example, a circle 501 indicates a threshold value for generating a conveyance error alarm. If the amount of eccentricity (Δx ₁ , Δy ₁ ) further increases, it may be determined that a conveyance error has occurred. For example, a circle 502 indicates a threshold value for generating a transport error alarm. When the plot is inside the circle 501, the transfer device 110 may be determined to be operating normally. When the plot is between the circle 501 and the circle 502, an alarm for a transport error is generated or displayed. If the plot is outside the circle 502, a transport error alarm is generated or displayed. In this case, the operation of the transfer robot 109 may be stopped.

A sensor for detecting the position of the transfer robot 109 and a control device for adjusting the position of the transfer robot 109 may be provided in the transfer device 110. The position of the transfer robot 109 detected by the sensor is fed back to the control device. Thereby, the position of the transfer robot 109 is always set to a predetermined position. In this way, it is possible to prevent the occurrence of a position error due to the transfer by the transfer robot 109. In this case, the eccentric amount (Δx ₁ , Δy ₁ ) represents a positional deviation between the transfer device 110 and the load lock chamber 107. By monitoring and accumulating the amount of wafer eccentricity in the pre-aligner 108 in this way, it becomes possible to specify a decrease in accuracy of transfer by the transfer robot 109 and a positional deviation between the transfer device 110 and the load lock chamber 107.

  In the method shown in FIG. 3, the position error caused by the transfer by the transfer robot 109 is eliminated by correcting the load position of the sample stage 106. However, there is a possibility that a position error and a rotation error due to the conveyance by the vacuum robot 104 have occurred. Therefore, the position error and rotation error caused by the conveyance by the vacuum robot 104 are eliminated. In the conventional inspection apparatus, global inspection by the optical microscope 103 is executed before inspection by the scanning electron microscope 102. Global alignment is wafer alignment. In this example, the position error and the rotation error caused by the conveyance by the vacuum robot 104 are eliminated in the global alignment. Further, the position error and the rotation error caused by the transfer by the vacuum robot 104 are reflected on the load position and the rotation angle of the pre-aligner for the next wafer 10.

With reference to FIG. 5, a method for inspecting a wafer by the inspection apparatus of this example and unloading after the inspection will be described. It is assumed that the wafer 10 has already been transferred onto the sample stage 106 by the method shown in FIG. In step S301, global alignment by the optical microscope 103 is executed. Global alignment is alignment for inspecting a wafer by the electron microscope 102, and is also executed by a conventional inspection apparatus. In the inspection apparatus of this example, the wafer on the sample stage 106 is observed by the optical microscope 103, and the positional deviation amount and the rotational deviation amount (ΔX ₁ , ΔY ₁ , Δθ ₁ ) with respect to the design value are measured. This error (ΔX ₁ , ΔY ₁ , Δθ ₁ ) represents a positional deviation amount and a rotational deviation amount caused by the transfer of the wafer 10 by the load hand 202 of the vacuum robot 104. In the global alignment of this example, this error (ΔX ₁ , ΔY ₁ , Δθ ₁ ) is eliminated.

In step S302, the load position (X _L , Y _L ) of the sample stage 106 with respect to the next wafer and the rotation angle (θ _L ) of the pre-aligner are corrected using the positional deviation amount and the rotational deviation amount. The corrected load position is (X _L + ΔX ₁ , Y _L + ΔY ₁ ), and the corrected pre-aligner rotation angle is (θ _L + Δθ ₁ ).

In step S303, the wafer 10 is inspected with a scanning electron microscope. When the inspection is completed, the sample stage 106 is moved to the unload position (X _U , Y _U ) in step S304. On the other hand, in step S305, the transfer robot 109 transfers the second wafer onto the pre-aligner 108. In step S306, pre-alignment of the second wafer is executed, and the pre-aligner is rotated with respect to the reference position by the rotation angle (θ _L + Δθ ₁ ) of the pre-aligner corrected in step S302. In this way, it is possible to correct the rotational deviation caused by the conveyance by the vacuum robot 104 detected in step S301.

In step S307, the eccentricity (Δx ₂ , Δy ₂ ) of the _second wafer on the pre-aligner 108 is measured. The eccentricity (Δx ₂ , Δy ₂ ) represents a position error caused by the transfer by the transfer robot 109 as described above. When step S305 to step S307 are completed, the process proceeds to the next step S308.

In step S308, the inspected wafer on the sample stage 106 and the uninspected wafer on the pre-aligner 108 are simultaneously lifted by the vacuum robot 104. In step S309, the corrected load position obtained in step S302 is further corrected based on the eccentricity (Δx ₂ , Δy ₂ ) obtained in step S307. The method of correcting the load position based on the eccentricity (Δx ₂ , Δy ₂ ) has been described in step S205 in FIG.

  Thus, the load position of the sample stage 106 is corrected for both the error caused by the vacuum robot 104 and the error caused by the transfer robot 109. In step S310, the sample stage 106 is moved to the corrected load position.

  In step S 311, the inspected first wafer is transferred to the pre-aligner 108 by the vacuum robot, and the uninspected second wafer is transferred onto the sample stage 106. In step S312, the eccentricity of the inspected wafer on the pre-aligner 108 is measured. The amount of eccentricity indicates the amount of displacement due to the transfer of the wafer 10 by the unload hand 203 of the vacuum robot 104. In step S313, the inspected wafer is unloaded into the FOUP 112 by the transfer robot 109.

  On the other hand, the inspection process from step S301 is performed on the second wafer mounted on the sample stage 106 in the same manner as the first wafer.

  The positional deviation amount detected in step S301 indicates a positional error caused by the transfer of the wafer 10 by the load hand 202 of the vacuum robot 104. The amount of eccentricity detected in step S312 indicates a misalignment caused by the transfer of the wafer 10 by the unload hand 203. These eccentricity data are accumulated and monitored, and an alarm is generated when the eccentricity is large or when the eccentricity increases. Thereby, the maintenance timing of the load hand 202 and the unload hand 203 of the vacuum robot 104 can be known. Further, the positional deviation amount Δθ in the rotation direction of the wafer detected in step S301 can be used to correct the measured value of the image when the wafer is inspected by the scanning electron microscope in step S303. is there.

  A second example of the inspection apparatus of the present invention will be described with reference to FIG. The inspection apparatus of this example includes a sample chamber 101, two load lock chambers 107A and 107B, and a mini-environment transfer device 110. In the sample chamber 101, a scanning electron microscope 102, an optical microscope 103, a sample stage 106, and a single hand type vacuum robot 104C are provided. The sample stage 106 is provided with an electrostatic chuck 105. The sample stage 106 can move in the XY directions and rotate. A pre-aligner 108A is provided in the load-side load lock chamber 107A. The unload side load lock chamber 107B is provided with an after aligner 108B. The transfer device 110 is provided with a transfer robot 109. A load port 111 is provided outside the transfer device 110, and a hoop 112 is disposed there.

  The transfer robot 109 takes out the load wafer 10 from the FOUP 112 and places it on the pre-aligner 108A of the load-side load lock chamber 107A. The transfer robot 109 unloads the wafer on the after aligner 108B of the unload side load lock chamber 107B into the FOUP 112.

  The single-handed vacuum robot 104C simultaneously holds the load wafer on the pre-aligner 108A of the load-side load lock chamber 107A and the unload wafer on the sample stage 106, and rotates the main arm. Thus, the load wafer is transferred onto the sample stage 106, and the unload wafer is transferred onto the after aligner 108B of the unload side load lock chamber 107B.

  Also in the inspection apparatus of this example, the processes shown in FIGS. 3 and 5 are possible. Therefore, in this example, the position error caused by the transfer by the transfer robot 109 can be monitored by measuring, storing, and monitoring the eccentric amount of the load wafer on the pre-aligner 108A of the load side load lock chamber 107A. . Furthermore, the optical microscope 103 can monitor the amount of positional deviation and the amount of rotational deviation caused by the transfer of the wafer 10 by the single-handed vacuum robot 104C.

  In the inspection apparatus shown in FIG. 1, when the inspection processing speed by the scanning electron microscope 102 is improved, the second wafer is not prepared in the pre-aligner 108 even though the inspection processing of the first wafer is completed. There is a possibility of becoming a state. In such a case, the wafer cannot be replaced by the vacuum robot 104. In order to cope with such a situation, as described below, a plurality of load lock chambers and vacuum robots may be mounted.

  A third example of the inspection apparatus of the present invention will be described with reference to FIG. The inspection apparatus of this example includes a sample chamber 101, two load lock chambers 107A and 107B, and a mini-environment transfer device 110. In the sample chamber 101, a scanning electron microscope 102, an optical microscope 103, a sample stage 106, and two vacuum robots 104A and 104B are provided. The sample stage 106 is provided with an electrostatic chuck 105. The sample stage 106 can move in the XY directions and rotate. Pre-aligners 108A and 108B are provided in the load lock chambers 107A and 107B, respectively. The transfer device 110 is provided with a transfer robot 109. A load port 111 is provided outside the transfer device 110, and a hoop 112 is disposed there.

  In the inspection apparatus of this example, the wafer is sequentially transferred to the load lock chambers 107A and 107B by the transfer robot 109. Wafer pre-alignment is sequentially performed in each pre-aligner 108A and 108B. Of the two wafers, the one for which the pre-alignment and the eccentricity measurement have been completed first is replaced with an inspected wafer on the sample stage 106 by the vacuum robot 104A or 104B.

  Also in the inspection apparatus of this example, the processes shown in FIGS. 3 and 5 are possible. However, in the inspection apparatus of this example, both of the two load lock chambers 107A and 107B can be loaded with a loading wafer and an unloading wafer. Therefore, the order of the wafers taken out of the FOUP 112 by the transfer robot 109 and the order of inspection by the scanning electron microscope 102 and unloading to the FOUP 112 by the transfer robot 109 are not necessarily the same. Therefore, it is necessary to match the wafer data inspected by the inspection apparatus with the identification number of the wafer itself.

  Although the number of load lock chambers is two in this example, the present invention can be applied even if the number is larger than that.

  The example of the present invention has been described above, but the present invention is not limited to the above-described example, and various modifications can be easily made by those skilled in the art within the scope of the invention described in the claims. Will be understood.

10 ... wafer, 101 ... sample chamber, 102 ... scanning electron microscope, 103 ... optical microscope, 104 ... vacuum robot, 105 ... electrostatic chuck, 106 ... sample stage, 107 ... load lock chamber, 108 ... pre-aligner, 109 ... transport Robot 110, Conveyor 111, Load port, 112 Hoop, 201 Main arm, 202 Road hand, 203 Unload hand

Claims (21)

A sample chamber to be evacuated, a sample stage provided in the sample chamber, a scanning electron microscope for inspecting a sample on the sample stage, a load lock chamber connectable to the sample chamber, and the load lock A pre-aligner provided in a room; a vacuum robot for loading a sample on the pre-aligner onto the sample stage; and unloading a sample on the sample stage onto the pre-aligner; In an inspection apparatus having a transfer robot for unloading a sample on a pre-aligner to the outside,
A memory for storing the load position (X _L , Y _L ) and unload position (X _U , Y _U ) of the sample stage and the rotation angle (θ _L ) of the pre-aligner is provided,
The transfer robot transfers the wafer onto the pre-aligner in the load lock chamber, executes pre-alignment for rotating the wafer on the pre-aligner by the rotation angle (θ _L ) with respect to a reference orientation, eccentricity of the wafer (Δx _1, Δy ₁₎ were measured, by the eccentric amount (Δx _1, Δy _1), the load position (X _L, Y _L) is configured to correct,
An inspection apparatus which generates an alarm when the amount of eccentricity (Δx ₁ , Δy ₁ ) of the wafer on the pre-aligner changes linearly along a predetermined tendency for each transfer . A sample chamber to be evacuated, a sample stage provided in the sample chamber, a scanning electron microscope for inspecting a sample on the sample stage, a load lock chamber connectable to the sample chamber, and the load lock A pre-aligner provided in a room; a vacuum robot for loading a sample on the pre-aligner onto the sample stage; and unloading a sample on the sample stage onto the pre-aligner; and loading a sample from the outside onto the pre-aligner In an inspection apparatus having a transfer robot for unloading a sample on a pre-aligner to the outside,
Load position of the sample stage (X _L , Y _L ) And unload position (X _U , Y _U ) And the rotation angle of the pre-aligner (θ _L ) Is stored,
The transfer robot transfers the wafer onto the pre-aligner in the load lock chamber, and the rotation angle (θ _L ) Is rotated, and the wafer eccentricity relative to the pre-aligner (Δx ₁ , Δy ₁ ) And the amount of eccentricity (Δx ₁ , Δy ₁ ), The load position (X _L , Y _L ) To compensate,
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ An inspection device that generates an alarm when) changes randomly. A sample chamber to be evacuated, a sample stage provided in the sample chamber, a scanning electron microscope for inspecting a sample on the sample stage, a load lock chamber connectable to the sample chamber, and the load lock A pre-aligner provided in a room; a vacuum robot for loading a sample on the pre-aligner onto the sample stage; and unloading a sample on the sample stage onto the pre-aligner; and loading a sample from the outside onto the pre-aligner In an inspection apparatus having a transfer robot for unloading a sample on a pre-aligner to the outside,
Load position of the sample stage (X _L , Y _L ) And unload position (X _U , Y _U ) And the rotation angle of the pre-aligner (θ _L ) Is stored,
The transfer robot transfers the wafer onto the pre-aligner in the load lock chamber, and the rotation angle (θ _L ) Is rotated, and the wafer eccentricity relative to the pre-aligner (Δx ₁ , Δy ₁ ) And the amount of eccentricity (Δx ₁ , Δy ₁ ), The load position (X _L , Y _L ) To compensate,
  Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ ) Will change linearly according to a predetermined trend for each transport, an alarm will be generated,
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ An inspection device that generates an alarm when) changes randomly. In the inspection apparatus according to any one of claims 1 to 3 ,
The corrected load position is (X _L + Δx ₁ cos θ _L + Δy ₁ sin θ _L , Y _L −Δx ₁ sin θ _L + Δy ₁ cos θ _L ). In the inspection apparatus according to any one of claims 1 to 3 ,
The sample stage is moved to the load position, and the wafer on the pre-aligner in the load lock chamber is transferred onto the sample stage by the vacuum robot, and before the inspection of the sample by the scanning electron microscope, Execute global alignment to measure the wafer positional deviation amount and rotational deviation amount (ΔX ₁ , ΔY ₁ , Δθ ₁ ) on the sample stage, and use the wafer positional deviation amount and rotational deviation amount to perform the next inspection. An inspection apparatus for correcting the load position (X _L , Y _L ) and the rotation angle (θ _L ) of the sample stage with respect to a wafer for measurement. The inspection apparatus according to claim 5 , wherein
An inspection apparatus characterized in that alignment of a wafer on the sample stage in the global alignment is performed using an optical microscope. In the inspection apparatus according to any one of claims 1 to 3 ,
The load position (X _L , Y _L ) of the sample stage is the center position on the sample stage when the wafer placed at the center position of the pre-aligner is transferred onto the sample stage by the vacuum robot. Is set as the position of the sample stage when placed in
The unload position (X _U , Y _U ) of the sample stage is such that when the wafer placed at the center position on the sample stage is transported to the pre-aligner by the vacuum robot, the wafer is placed on the table of the pre-aligner. Set as the position of the sample stage when placed in the center position,
The rotation angle (θ _L ) of the pre-aligner is such that when the wafer on the pre-aligner is transferred onto the sample stage by the vacuum robot, the arrangement pattern of the wafer is arranged along the X direction or the Y direction of the sample stage. The inspection apparatus is set as a rotation angle with respect to a reference orientation of the wafer on the pre-aligner at the time. The inspection apparatus according to claim 1 or 3 ,
When the amount of eccentricity (Δx ₁ , Δy ₁ ) of the wafer on the pre-aligner changes linearly along a predetermined tendency for each transfer, the transfer device in which the transfer robot is arranged and the load lock chamber An inspection apparatus that judges that a positional deviation has occurred between them and displays an alarm indicating the misalignment. The inspection apparatus according to claim 2 or 3 ,
When the amount of eccentricity (Δx ₁ , Δy ₁ ) of the wafer on the pre-aligner changes at random, it is determined that the transfer accuracy is lowered by the transfer robot, and an alarm indicating that is displayed. Inspection device. In the inspection apparatus according to any one of claims 1 to 3 ,
When the amount of eccentricity (Δx ₁ , Δy ₁ ) of the wafer on the pre-aligner is larger than the first threshold value and smaller than the second threshold value, an alarm of occurrence of a position error is generated and the eccentricity amount (Δx ₁ , Δy of the wafer) is generated. _{When 1} ) is larger than the second threshold value, an inspection apparatus that displays an alarm indicating the occurrence of a transport error is displayed. A sample chamber to be evacuated, a load lock chamber provided with a pre-aligner and connectable to the sample chamber, a sample stage provided in the sample chamber, and a scanning electron microscope for inspecting a sample on the sample stage; In an inspection method for inspecting a sample by an inspection apparatus having
Storing the load position (X _L , Y _L ) and unload position (X _U , Y _U ) of the sample stage and the rotation angle (θ _L ) of the pre-aligner;
An uninspected wafer transfer step of transferring a wafer onto the pre-aligner by a transfer robot;
A pre-alignment execution step of evacuating the load lock chamber and rotating the wafer on the pre-aligner by the rotation angle (θ _L ) with respect to a reference orientation;
An uninspected wafer eccentricity measuring step for measuring an eccentricity (Δx ₁ , Δy ₁ ) of the wafer relative to the pre-aligner;
A first load position correcting step for correcting the load position (X _L , Y _L ) based on the eccentricity (Δx ₁ , Δy ₁ );
A sample stage moving step for moving the sample stage to the corrected load position;
An uninspected wafer loading step of transferring a wafer on the pre-aligner onto the sample stage by a vacuum robot;
A global alignment execution step for aligning the wafer on the sample stage;
An inspection step of inspecting the wafer by the scanning electron microscope;
A sample stage moving step for moving the sample stage to the unload position (X _U , Y _U );
I have a,
The method further includes a first alarm generation step for generating an alarm when the amount of eccentricity (Δx ₁ , Δy ₁ ) of the wafer on the pre-aligner changes linearly along a predetermined tendency for each transfer. inspection how to. A sample chamber to be evacuated, a load lock chamber provided with a pre-aligner and connectable to the sample chamber, a sample stage provided in the sample chamber, and a scanning electron microscope for inspecting a sample on the sample stage; In an inspection method for inspecting a sample by an inspection apparatus having
Load position of the sample stage (X _L , Y _L ) And unload position (X _U , Y _U ) And the rotation angle of the pre-aligner (θ _L )
An uninspected wafer transfer step of transferring a wafer onto the pre-aligner by a transfer robot;
The load lock chamber is evacuated, and the wafer on the pre-aligner is rotated with respect to a reference orientation (θ _L ) Rotation pre-alignment execution step,
Eccentricity of the wafer relative to the pre-aligner (Δx ₁ , Δy ₁ ) To measure the unexamined wafer eccentricity measuring step,
The amount of eccentricity (Δx ₁ , Δy ₁ ) Based on the load position (X _L , Y _L ) For correcting the first load position,
A sample stage moving step for moving the sample stage to the corrected load position;
An uninspected wafer loading step of transferring a wafer on the pre-aligner onto the sample stage by a vacuum robot;
A global alignment execution step for aligning the wafer on the sample stage;
An inspection step of inspecting the wafer by the scanning electron microscope;
The sample stage is moved to the unload position (X _U , Y _U Sample stage moving step to be moved to
Have
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ The inspection method further includes a second alarm generation step of generating an alarm when the) changes randomly. A sample chamber to be evacuated, a load lock chamber provided with a pre-aligner and connectable to the sample chamber, a sample stage provided in the sample chamber, and a scanning electron microscope for inspecting a sample on the sample stage; In an inspection method for inspecting a sample by an inspection apparatus having
Load position of the sample stage (X _L , Y _L ) And unload position (X _U , Y _U ) And the rotation angle of the pre-aligner (θ _L )
An uninspected wafer transfer step of transferring a wafer onto the pre-aligner by a transfer robot;
The load lock chamber is evacuated, and the wafer on the pre-aligner is rotated with respect to a reference orientation (θ _L ) Rotation pre-alignment execution step,
Eccentricity of the wafer relative to the pre-aligner (Δx ₁ , Δy ₁ ) To measure the unexamined wafer eccentricity measuring step,
The amount of eccentricity (Δx ₁ , Δy ₁ ) Based on the load position (X _L , Y _L ) For correcting the first load position,
A sample stage moving step for moving the sample stage to the corrected load position;
An uninspected wafer loading step of transferring a wafer on the pre-aligner onto the sample stage by a vacuum robot;
A global alignment execution step for aligning the wafer on the sample stage;
An inspection step of inspecting the wafer by the scanning electron microscope;
The sample stage is moved to the unload position (X _U , Y _U Sample stage moving step to be moved to
Have
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ ) Changes linearly along a predetermined trend for each conveyance, a first alarm generation step for generating an alarm;
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ ) Changes randomly, a second alarm generation step for generating an alarm;
An inspection method further comprising: In the inspection method according to any one of claims 11 to 13 ,
In the uninspected wafer loading step by the vacuum robot, when the wafer on the pre-aligner is transferred onto the sample stage by the vacuum robot, the wiring pattern of the wafer on the sample stage is in the X direction or Y direction of the sample stage. The inspection method is characterized in that the rotation angle (θ _L ) is set so as to be arranged along the line. In the inspection method according to any one of claims 11 to 13 ,
In the global alignment execution step, the positional deviation amount and rotational deviation amount (ΔX ₁ , ΔY ₁ , Δθ ₁ ) of the wafer on the sample stage with respect to the design value are measured, and the positional deviation amount and rotational deviation amount of the wafer are used. Then, the load position (X _L , Y _L ) and the rotation angle (θ _L ) for the next inspection wafer are corrected (X _L + ΔX ₁ , Y _L + ΔY ₁ , θ _L + Δθ ₁ ). Inspection method characterized by The inspection method according to claim 15 , wherein
An uninspected wafer transfer step of transferring a wafer for next inspection onto the pre-aligner by a transfer robot;
An uninspected wafer eccentricity measuring step for measuring an eccentricity (Δx ₂ , Δy ₂ ) of the wafer for the next inspection with respect to the pre-aligner;
Second load position correction for correcting the corrected load position (X _L + ΔX ₁ , Y _L + ΔY ₁ ) based on the eccentricity (Δx ₂ , Δy ₂ ) of the next wafer for inspection. Steps,
Moving the sample stage to a load position after being corrected in the second load position correcting step;
Transporting the next inspection wafer on the pre-aligner onto the sample stage by the vacuum robot;
Including inspection methods. In the inspection method according to any one of claims 11 to 13 ,
An inspected wafer unloading step of transferring the inspected wafer on the sample stage onto the pre-aligner by the vacuum robot;
An inspected wafer eccentricity measuring step for measuring an eccentricity of the inspected wafer with respect to the pre-aligner;
An inspected wafer transfer step of transferring the inspected wafer on the pre-aligner out of the load lock chamber by the transfer robot;
An inspection method characterized by comprising: The inspection method according to claim 17 ,
The inspected wafer unloading step by the vacuum robot transports the inspected wafer on the sample stage onto the pre-aligner by the vacuum robot, and simultaneously transfers the next inspection wafer on the pre-aligner to the sample stage. Inspection method characterized by transporting upward. In the inspection method according to any one of claims 11 to 13 ,
In the first load position correction step, the corrected load position is (X _L + Δx ₁ cos θ _L + Δy ₁ sin θ _L , Y _L −Δx ₁ sin θ _L + Δy ₁ cos θ _L ). Inspection method. The inspection method according to claim 11 or 13,
The first alarm generation step includes:
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ ) Changes linearly in accordance with a predetermined tendency for each transfer, it is determined that a positional deviation has occurred between the transfer device in which the transfer robot is disposed and the load lock chamber. And displaying an alarm indicating the inspection method. The inspection method according to claim 12 or 13,
The second alarm generation step includes:
Eccentricity of wafer on the pre-aligner (Δx ₁ , Δy ₁ ) Changes at random, it is determined that the transfer accuracy is lowered by the transfer robot, and an alarm indicating the change is displayed.

Images