JP5222091B2 - Charged particle beam equipment - Google Patents

Description

  The present invention relates to a charged particle beam apparatus that inspects an object to be inspected.

  In recent years, due to miniaturization of semiconductor processes and an increase in the diameter of semiconductor wafers, dimensional inspection of fine patterns on wafers and inspection of fine defects have been frequently used using charged particle beams.

  The semiconductor wafer size currently has a radius of 300 [mm], but an increase in diameter to 450 [mm] is being studied in the near future.

  Also, the pattern dimension is 35 [nm] or less, and these dimension inspections and pattern defect inspections require higher precision measurement, and it is desired to increase the resolution of the charged particle beam apparatus.

  On the other hand, the pattern positioning of the semiconductor wafer of such various charged particle beam apparatuses is performed in a two-axis coordinate system orthogonal to X and Y. For this reason, not only the apparatus becomes large and expensive, but also the image resolution of the charged particle beam apparatus is further improved, and image degradation due to slight vibration of the sample stage is also a problem.

  Furthermore, the clean room in which the charged particle beam apparatus is installed is very expensive for further cleaning, floor vibration prevention, and the like, and it is desired to reduce the cost of the charged particle beam apparatus.

  With respect to such a problem, the technique described in Patent Document 1 eliminates the necessity of providing a preliminary exhaust chamber in the moving range of the sample stage and separately providing a sample moving means between the preliminary exhaust chamber and the sample chamber. Therefore, the size is reduced.

  In addition, according to the technique described in Patent Document 2, the sample stage can be rotated, and the entire sample stage can be rotated by an arm that supports the sample stage. The size of the particle beam device is being reduced.

Japanese Patent No. 3389788 JP-A-8-162057

  However, according to the technique described in Patent Document 2, it is possible to reduce the size of the sample stage, but it is not considered to improve the inspection accuracy according to the pattern miniaturization of the semiconductor wafer, and the size is small. However, it has been difficult to improve the inspection accuracy such as the size and defects of the inspection target such as a semiconductor wafer.

  An object of the present invention is to realize a charged particle beam apparatus that is small and inexpensive and has improved inspection accuracy corresponding to pattern miniaturization of an inspection object.

  In order to achieve the above object, the present invention is configured as follows.

  A charged particle beam device according to the present invention includes a rotary stage for rotating an object to be inspected, a means for rotationally driving the rotary stage, a rotary arm for moving the rotary stage in an arc shape, a means for driving the rotary arm, Charged particle beam inspection means to inspect the inspection object by irradiating the inspection object placed on the rotary stage to inspect the inspection object, and charged particle beam inspection of the inspection position of the inspection object placed on the rotation stage In order to move to the position where the charged particle beam from the means is irradiated, the rotation angle of the rotation arm and the rotation angle of the rotation stage are calculated, and the rotation arm driving means and the stage rotation are calculated based on the calculated rotation angle. Control means for driving the drive means.

  A charged particle beam apparatus with improved inspection accuracy corresponding to pattern miniaturization of an inspection object can be realized while being small and inexpensive.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of an entire system of a charged particle beam apparatus according to an embodiment of the present invention. This charged particle beam apparatus is for a large-diameter wafer and is formed of a rotary arm mechanism and a rotary stage mechanism. And a two-axis rotary stage mechanism.

  In the charged particle beam apparatus, various feature quantities on the sample surface are detected by detecting and analyzing secondary signals generated by irradiating the charged particle beam from above while keeping the sample chamber 101 in a high vacuum. The sample chamber 101 incorporates a two-axis rotary stage mechanism composed of a rotary arm 102 and a rotary stage 103, and these are controlled by a control computer 104.

  The rotating arm 102 has a rotating shaft supported by a bearing in a vacuum and can rotate. The end of the rotating arm 102 opposite to the end where the rotating shaft is formed is configured by a piezoelectric element. It is configured to be driven and rotated by a driven motor (not shown). The rotation shaft is provided with a rotation angle detector (not shown). Further, the end of the rotary arm 102 opposite to the end where the rotation axis is formed is guided by a guide mechanism that supports this end, and the rotary arm 102 is cantilevered. Instead, it is supported by both ends, is strong against external vibration, and is rotationally driven in an arc shape without rattling.

  The rotary stage 103 supported by the rotary arm is rotationally driven by a drive motor (not shown) constituted by a piezoelectric element.

  When the operator designates a sample wafer to be inspected from the man-machine interface 105, the designated wafer is taken out by the wafer transfer robot 109 from the pod 112 placed on the load port 111.

  The wafer transfer unit 108 in which the wafer transfer robot 109 is installed is a typical sample wafer transfer mechanism that maintains a high cleanliness state in order to prevent foreign matter from adhering to the sample wafer. After purging the sample chamber 101 to the atmosphere, the gate valve 110 is opened and placed directly on the rotary stage 103. Thereafter, the gate valve 110 is closed, the sample chamber 101 is evacuated again to form a high vacuum state, and charged particles are inspected and measured.

  The man-machine interface 105 has an input mechanism 107 or a communication function corresponding to the input mechanism 107, and can input design information and shot arrangement information of a semiconductor chip formed on the sample wafer. These information are held in the storage device 106. The

  In the configuration as described above, as an example, FIG. 2 shows a conversion from the wafer coordinate system 201 (FIG. 2B) assuming a 450 mm wafer to the stage coordinate system 202 of the biaxial rotating stage mechanism. Explanatory drawing about is shown. Note that the control computer 104 executes the following operations such as coordinate transformation.

2A and 2B, the distance from the rotation arm rotation center 204 to the rotation center of the rotation stage 103, that is, the rotation radius is R1, and the rotation radius with respect to the rotation stage rotation center 205 (the radius of the rotation stage). In the case of R2, the minimum required rotation angle S _1min of the ideal rotating arm 102 is expressed by the following equation (1).

S _1min = 2 · sin ⁻¹ {R ₂ / (2R ₁ )} (1)
Assuming that the inspection mechanism installation position 203 is installed so as to coincide with the rotation stage rotation center 205 when the rotation amount of the rotation arm is 0, an arbitrary inspection point (wx, wy) designated in the wafer coordinate system 201 is installed. rotating arm rotation angle S ₁ and the rotary stage rotation angle S ₂ for moving the position 203 can be determined as follows.

  That is, the coordinates of the wafer coordinate system 201 are converted into polar coordinates from the wafer center. Since the radius of the sample wafer is 450 [mm], the converted polar coordinates (wr, ws) are expressed by the following equations (2-1) to (2-4).

wx-255 = wr · cos (ws) (2-1)
wr-255 = wr · sin (ws) (2-2)
wr = √ {(wx-255) ² + (wy-255) ² } (2-3)
ws = tan ⁻¹ {(wy−255) / (wx−255)} (2-4)
Since the rotation arm rotation angle S ₁ is determined only by wr, the following equation (3).

S ₁ = 2 · sin ⁻¹ {wr / (2R ₁ )} (3)
When the visual field shift angle generated by driving the rotation arm rotation angle S ₁ is S _cor , this S _cor is expressed by the following equation (4).

S _cor = S ₁ −cos ⁻¹ {R ₁ · sin (S ₁ ) / wr} (4)
These results, the rotary stage rotation angle S ₂ from the angular component ws and S _cor calculated from the wafer coordinates can be expressed by the following equation (5).

S ₂ = −ws + S _cor (5)
In the two-rotation axis stage, when the designated inspection point (wx, wy) is moved directly below the attachment position 203 of the inspection mechanism described later, the sample angle has changed. For this reason, when the charged particle beam apparatus is installed at the inspection mechanism attachment position 203, the well-known raster rotation function is used to correct the field rotation correction by _Sr as shown in the following equation (6). By doing so, an image in the positive direction can be obtained.

_{S r = S 1 -S 2 ···} (6)
The most obvious cause of the positional deviation between the wafer coordinate system 201 and the coordinate system 202 of the two-axis rotary stage is the deviation between the wafer center and the rotary stage rotation center 205.

  As described above, it can be considered that the amount of deviation assumed when the sample (wafer) is directly placed on the rotary stage 103 without going through the pre-alignment process occurs on the order of several [mm].

When the minimum required rotation angle S _{1 min} of the rotary arm 102 is constructed as shown in the equation (1), this deviation amount causes an area that cannot be observed outside the sample wafer. This can be improved by providing a rotation angle margin S _1mrg in consideration of an allowable deviation amount with respect to the minimum required rotation angle S _1min .

When the allowable deviation amount is Dwr _max , an outside dead zone is generated due to a deviation between the wafer center and the rotation stage rotation center 205 by providing a rotation angle margin _{equal to} or greater than the rotation angle margin S 1 _mrg shown by the following equation (7). Can be prevented.

S 1 _mrg = (Dwr _max / R ₁ ) [rad] (7)
Conversely, if the deviation between the wafer center and the rotation stage rotation center 205 is substantially zero, the inspection mechanism installation position margin 206 can be provided by the rotation angle margin S 1 _mrg . The deviation of the rotation stage rotation center 205 with respect to the observation center at the inspection mechanism attachment position 203 causes an unobservable region inside the sample wafer in the vicinity of the observation center.

The _provision of the inspection mechanism installation position margin 206 by the rotation angle margin S _1mrg means that when the inspection mechanism is installed on the circumference of the rotation stage rotation center 205 with respect to the rotation arm rotation center 204, a deviation from the circumferential direction is caused. It is how much you accept the quantity.

  That is, as long as it is within the range of the inspection mechanism installation position margin 206, it is possible to prevent the inside non-observable region from being generated at any position. In the two-axis rotary stage mechanism shown in FIG. 2, the inspection mechanism attachment position 208 can be provided at another point.

The inspection mechanism attachment position 208 is provided at a position rotated by S _{1 min} + S _{1 mrg} or more in the circumferential direction of the rotation arm with respect to the inspection mechanism attachment position 203. Since the inspection mechanism attachment position 208 needs to reverse the control of the rotary arm 102 to the inspection mechanism attachment position 203, the installation position is set to S _{1 min} + S _{1 mrg} or more, thereby preventing the occurrence of an unobservable region outside. can do.

FIG. 3 shows a configuration in which the configuration is further expanded so that the inspection mechanism installation margin 206 is set large (margin 304) and S _1mrg = S _{1 min} . By _setting S _1mrg = S _{1 min} , all the circumferences connecting the three representative inspection mechanism attachment positions (1) 301 to the inspection mechanism attachment positions (3) 303 are inspection mechanism installation margins.

The example shown in FIG. 3 is an example when R1 = 300 [mm] and R2 = 225 [mm]. In this case, S _1min = 44.048626 ° and S _1max * 2 is 88.0973 °. It is the composition which becomes. In this example, R1 is selected so that the chamber is as square as possible, and the inside of the sample chamber 101 is configured with X = Y = 750 [mm] as a minimum value, and a margin of about 7.5 [mm] is provided. Can be provided. This margin is an inspection mechanism installation margin (2) 305 that is effective with respect to the inspection mechanism attachment position (2) 302, and the other attachment positions are provided with margins 301 and 303 corresponding to S _1mrg = 44.048626 °. Become.

  The inspection mechanism attachment position (2) 302 corresponds to the position at which the end face of the sample wafer is observed when observing the center of the sample wafer at the inspection mechanism attachment position (1) 301 or the inspection mechanism attachment position (3) 303. Assuming that the stage position corresponding to the inspection mechanism attachment position (1) 301 is the sample carry-in / out position, the inspection mechanism attachment position (2) 302 is observing the wafer end face when carrying the sample.

  In the charged particle beam apparatus, a configuration in which an optical microscope is mounted for observing a low-magnification image is often seen, but it can be used for pre-alignment by arranging it at the inspection mechanism mounting position (2) 302. . Assuming that the amount of displacement of the sample wafer is several [mm], the gate valve 110 is closed after the sample is loaded by installing a low-magnification optical microscope that includes this or combining it with the rotational operation of the rotary stage 103. It is possible to perform misalignment correction amount calculation (pre-alignment) in parallel during the evacuation waiting time. Here, the pre-alignment is calculation of a correction amount for a positional deviation between the rotation stage rotation center 205 and the sample wafer center.

  On the circumference connecting the inspection mechanism attachment positions (1) to (3) in FIG. 3, it is possible to cover the entire surface of the sample wafer no matter where the inspection mechanism is attached. Therefore, an auxiliary device peculiar to the inspection of the semiconductor device, for example, a device for measuring the charged electric field on the surface of the sample wafer is attached to the position 307 on the circumference, and a device for removing the electric field is attached to the position 308, thereby inspecting performance. It can be expected to improve. Moreover, it can be expected that the inspection performance can be improved by attaching the outer periphery exclusive inspection mechanism to the position 309.

  Auxiliary device attachment positions relative to the inspection mechanism attachment positions 301 to 303 and 307 to 309 can be moved only by driving the rotary arm 102, and charge measurement and charge removal operations are dynamically performed on inspection points on the sample wafer. Therefore, the accuracy can be improved as compared with the conventional processing for the entire surface. When processing on the entire surface is necessary, by combining the driving of the rotating arm 102 and the driving of the rotating stage 103 and applying mechanical scanning such as linear scanning on the sample surface and spiral scanning, processing on the entire surface of the sample wafer is performed. Can be done.

FIG. 4 is an explanatory diagram of the configuration when the configuration is further expanded so that R ₁ = R ₂ . The example shown in FIG. 4 is a case where R ₁ = 225 [mm] and R ₂ = 225 [mm]. In this case, S _1min = 60.0 ° and S _1max * 2 is 120.0 °. It is the composition which becomes. Rotating arm rotation center 204 by this construction, irrespective of the rotation arm angle S _1, always be consistent with the sample wafer periphery. This position can be used as the position for attaching the inspection mechanism for the outer periphery of the sample wafer 404. For example, by attaching a low-magnification optical microscope to the outer periphery dedicated inspection mechanism attachment position 404, it becomes possible to calculate a correction amount and to perform pre-alignment with respect to the positional deviation between the rotation stage rotation center 205 and the sample wafer center.

  Further, even when pre-alignment with respect to each inspection mechanism attachment position is necessary due to the blurring of the rotation center rotation center, pre-alignment with a low-magnification optical microscope attached to the outer circumference exclusive inspection mechanism attachment position 404 is possible.

  In addition, a dedicated inspection mechanism for performing quality control on the outer periphery of the sample wafer, which has been attracting attention in recent years, can be attached, and it is possible to specially perform inspection of foreign matter on the side surface of the sample wafer and observation of film peeling. In addition, when the outer peripheral exclusive inspection mechanism mounting position 404 is in an ideally free state, the sample can be rotated only by mechanical rotation, and combined with an obliquely arranged inspection mechanism, there are many inspection applications. Expanding.

  Reference numerals 401, 402, and 403 denote inspection mechanism attachment positions.

  As described above, in order to perform the positioning control using the biaxial rotation stage mechanism described above, it is necessary to accurately measure how much the rotation center axis of the rotation stage 103 is shaken. Therefore, this is measured using a mark having a direction stamped at the center of the rotary stage 103. In each inspection mechanism, the control computer 104 detects a mark engraved at the center of the rotary stage 103 by an image processing technique, and in this state, rotates the rotary stage 103 from the rotation origin by 360 °.

FIG. 5 is an explanatory view of the rotation center axis fluctuation. As shown in FIG. 5, at the same time as the rotation, the mark is continuously extracted in image processing to create a mark locus 501 accompanying the rotation. From this information, an X-direction shake amount 502 and a Y-direction shake amount 503 with respect to the rotation stage rotation angle S ₂ are calculated and recorded in the storage device 106. At the same time, a rotation amount deviation amount 504 with respect to the designated rotation stage rotation angle is measured from the direction of the mark, stored in the storage device 106, and used as a correction amount for rotation stage control.

The trajectory data stored as described above is the amount of shake of the rotation stage rotation center 205 at each inspection mechanism position, and this inside is an unobservable region. This blurring amount is determined by the rotational angle S ₂ of the rotary stage 103. Rotation angle S ₂ is determined by the equation (5), which shaft wobble amount is added to the wafer coordinate system caused by, again, perform the calculations from the rotating arm rotation angle S ₁ by using the above formula (2).

Since this calculation will vibrate at a rotation angle detection resolution, it is obvious that the difference between the calculation results is less than the set threshold value and the process is terminated, or the number of calculations that converge empirically is obvious. In some cases, a fixed number of operations are repeated to determine S ₁ and S ₂ .

  Irradiation position adjustment (image shift) is performed by a charged particle beam apparatus for observation of an unobservable region. Since the upper limit value that can be corrected by adjusting the irradiation position is determined by the charged particle beam device to be approximately ± 15 [micro m], it must be adjusted so that the rotational axis shake amount is within the range. In addition, it is necessary to accurately measure the degree of positional deviation of the rotation stage rotation center with respect to the observation center of the inspection mechanism.

  Therefore, it is measured how much the center of gravity of the locus indicating the shake amount of the rotation stage rotation center 205 is deviated from the observation center in the visual field. The determination of the observation center follows the characteristics of the charged particle beam inspection mechanism installed at each mounting position. The displacement amount of the rotation center relative to the observation center for each inspection mechanism detected here is recorded in the storage device 106.

Rotation angle S ₁ direction circumferentially of the displacement of the rotary arm 102 is used for positioning calculation as an adjustment amount for controlling the amount S ₁ of the rotary arm 102.

As shown in FIG. 6, with respect to before adjustment of the rotary stage rotation center 601, S ₁ of the rotary arm axis direction caused in the rotation center 602 after the adjustment deviation amount 603, i.e., an inner unobservable area . This deviation amount is used as a correction amount by adjusting the irradiation position (image shift) by the charged particle beam apparatus. Since the upper limit value that can be corrected by adjusting the irradiation position is determined by the charged particle beam apparatus, it must be adjusted so that the observation center deviation amount falls within the range.

  As described above, the axial movement of the rotation stage rotation center 205 and the deviation amount of the rotation stage rotation center 205 with respect to the observation center are measured at the time of apparatus maintenance, and follow changes in the fluctuation amount and deviation amount with time.

  Further, it is necessary to accurately measure how much the wafer center is displaced with respect to the rotation stage rotation center 205. This is performed using an ultra-low magnification observation device, an optical microscope, a CCD camera, or the like provided at the outer periphery dedicated inspection mechanism attachment position 309 shown in FIG. In one embodiment of the present invention, the sample wafer is arranged on the rotary stage 103 in any direction and arbitrary position with a certain likelihood. In the measurement, after the sample wafer is placed on the rotary stage 103, the control computer 104 rotates the rotary stage 103 at a constant speed.

  The control computer 104 analyzes the moving image data obtained from the observation apparatus, and detects a portion where the end surface of the sample wafer is not a curve, that is, a V-shaped notch portion. Once detected, the rotary stage 103 is temporarily stopped, and the rotary stage 103 is rotated and stopped so that the V-shaped notch at the stopped position is aligned with the 270 ° direction of the sample chamber 101, that is, the direction opposite to the gate valve 110. .

  The rotation stage angle information at that time is stored in the storage device 106. As shown in FIG. 7, the control computer 104 calculates a wafer center misalignment amount 702 from the in-screen position 701 of the V-shaped notch aligned with the 270 ° direction, and from the rotation stage angle at this time, the rotation stage The amount of shaft shake is added and subtracted and stored in the storage device 106.

  At this time, it is assumed that the angle of the rotary stage 103 when the sample wafer is loaded is matched and stored. In general, the rotation origin is set. When the sample wafer is carried out, the loading position is restored by using the stored rotation stage angle. The positional relationship between the X and Y positions of the sample wafer with respect to the pod 112 depends on the rotation angle of the rotary stage 103, such as when the position deviation of the center of the sample wafer becomes large due to the deterioration of the position adjustment of the wafer transfer robot 109 and the load port 111. As a result, the sample wafer interferes and collides with the pod 112. By restoring the sample wafer carry-in position, the possibility of such an accident can be reduced.

  FIG. 8 is an explanatory diagram of a correspondence relationship between the mounting position of the inspection mechanism or the like shown in FIG. 3 and the inspection mechanism or the like. In FIG. 8, inspection mechanisms 901 to 903, a charge measuring device 904, a charge removal device 905, and an outer periphery dedicated inspection mechanism 906 are arranged on the upper surface of the sample chamber 101. The optical inspection apparatus 901 is attached at a position corresponding to the attachment position 301, the optical microscope 902 is attached at a position corresponding to the attachment position 302, and the charged particle beam inspection apparatus 903 is attached at a position corresponding to the attachment position 303. It has been.

  In addition, the charge measuring device 904 is attached at a position corresponding to the attachment position 307, the static eliminator 905 is attached at a position corresponding to the attachment position 308, and the outer periphery dedicated inspection mechanism 906 is located at a position corresponding to the attachment position 309. It is attached.

  FIG. 9 is a block diagram of a processing unit that performs the positioning process of the biaxial rotation stage based on each correction amount acquired as described above. In FIG. 9, the positioning process is roughly divided into a wafer coordinate system → polar coordinate conversion processing unit 801 and a polar coordinate → biaxial rotation stage coordinate conversion processing unit 802.

  The wafer coordinate system → polar coordinate conversion process 801 executes the calculation of the above formula (2), and the polar coordinate → biaxial rotation stage coordinate conversion processing unit 802 executes the calculations of the above expressions (3) to (5). The wafer coordinates 808 input by the operator must consider the amount of wafer center deviation before performing the polar coordinate conversion processing. Therefore, the wafer center deviation amount (X) calculated with respect to the input coordinates 808 is calculated. , Y) The data 803 is added or subtracted. Since the deviation amount (S) data 804 of the wafer center is the rotation stage angle rotated to align the V-shaped notch portion in the 270 ° direction of the sample chamber 101, this is a polar coordinate → biaxial rotation stage coordinate conversion processing unit. Step 802 adds to or subtracts from the calculated rotation stage rotation angle.

  On the other hand, each inspection mechanism attachment position 810 is stored in the storage device 106 as an offset of the rotation arm rotation angle information, and is selected according to the inspection mechanism designation 809 designated by the operator.

  Since there is a position shift of the rotation stage rotation center with respect to the observation center of each inspection mechanism 901 to 906, addition / subtraction of data 805 of the rotation stage rotation center shift amount with respect to the center of the visual field that can be corrected with respect to the rotation arm rotation direction. To correct the center of vision correction. The shift in the rotation arm axis direction cannot be corrected by the biaxial rotation stage, and is therefore absorbed separately by correction by irradiation position adjustment (image shift).

  The rotation arm control angle is determined by adding the rotation arm rotation angle calculated by the biaxial rotation stage coordinate conversion processing unit 802 to the rotation arm rotation angle for each of the inspection mechanisms 901 to 906 thus determined.

  Further, the rotation stage angle data calculated by the biaxial rotation stage coordinate conversion processing unit 802 is obtained by adding / subtracting the wafer center deviation amount (S) data 804, and then correcting the rotation amount deviation amount data 806 that has been measured. To determine the rotation stage control angle.

  Further, since the stage center shake occurs with respect to the rotation stage control angle determined here, the amount of the shake is calculated from the data 807 of the stage center shake (X, Y) accompanying the measured rotation, and is calculated with respect to the wafer coordinate system. Thus, it is possible to determine the control amount to be balanced by performing feedback.

  Furthermore, it is necessary to increase the positioning accuracy by accurately measuring the position of the semiconductor design pattern. The pattern on the sample wafer is determined so that the rotary arm 102 and the rotary stage 103 operate as much as possible. In the biaxial rotating mechanism stage, it is satisfied by selecting any three points arranged at both ends on the diameter passing through the vicinity of the center of the sample wafer.

  Therefore, the control computer 104 uses the data created by the operator via the man-machine interface, or the semiconductor design data obtained by the input mechanism 107 or a communication function corresponding thereto, to any arbitrary lined up at both ends on the diameter passing through the vicinity of the center. Three in-chip patterns are automatically determined, the in-chip pattern is detected by image processing before the inspection process in each inspection mechanism is started, and the positional deviation amount of the wafer center is minutely corrected based on the detected position. To do.

  This correction can also be performed by correcting the semiconductor arrangement information on the sample wafer. Further, when the semiconductor arrangement is distorted, higher accuracy can be expected by determining the chip on the circumference of the end of the sample wafer.

  The semiconductor array information correction data on the sample wafer created in the above procedure may be reused for the same product and the same process sample wafer in the development of high precision technology accompanying recent miniaturization of semiconductors. It can be considered very expensive.

  Therefore, the semiconductor array information correction data is stored in the storage device 106 in association with a code that can identify the semiconductor product and process, and is used when the product and process are inspected next time. By omitting the process, the throughput of the charged particle inspection apparatus can be improved.

  However, the semiconductor alignment information correction data can be corrected and learned from time to time based on position information recognized by processing in the inspection process, for example, length measurement position detection or defect pattern detection, so that the alignment accuracy can be kept uniform. Is possible. In addition, the semiconductor array information correction data is erased by instructing from the man-machine interface 105 when mechanical adjustment is performed by regular maintenance, and the semiconductor array information correction data is re-created by the positioning process. It becomes possible. The amount of movement of the rotary arm can cover the entire range of the wafer by using the rotary stage in combination with the rotary stage with a stroke of about half of the wafer diameter.

  As described above, according to the present invention, the inspection position (wafer coordinate system) of the sample to be inspected is converted into the arrangement position (stage coordinate system (polar coordinate system)) of the inspection mechanism, and the rotary arm 102 is rotated and rotated. The stage 103 is rotated to move the inspection position of the sample to be inspected to the arrangement position of the inspection mechanism. At this time, since the deviation amount of the center of the rotary stage 103 can be calculated and corrected, in the charged particle beam apparatus having the biaxial rotary stage mechanism, in response to pattern miniaturization of the inspection target, Inspection accuracy can be improved.

  In addition, since a plurality of inspection devices are arranged on the movement trajectory at the center of the rotary stage 103 drawn by the rotation of the rotary arm 102, a charged particle beam apparatus capable of performing a plurality of types of inspections while being small in size is provided. Can be realized.

  Furthermore, since the stage is miniaturized, the sample chamber surrounding it can be miniaturized. In addition to preventing external vibration by improving the synthesis, high-speed vacuum exhaust and low cost can be realized by miniaturizing the vacuum volume.

  More specifically, since the angle in the rotation direction of the wafer deviates from the scanning direction of the charged particle beam device when positioning is performed, the calculated particle amount is corrected as the rotation angle correction, and the scanning particle beam is always corrected. An erect image can be obtained in a direction determined on the notch side or the like.

In the present invention, the required operation amount of the rotation amount S ₁ of the rotation arm 102 is defined from the turning radius R ₁ of the rotation arm 102 and the rotation radius R ₂ of the rotation stage 103, and is expanded to thereby install the inspection apparatus. There is room. By further increasing this installation margin, as well as extend the mounting locations of a typical inspection mechanism, she is possible to correct the positional deviation correction in the rotational amount S ₁ of the rotating arm.

  Furthermore, as feature quantities that cause positional deviation in each inspection apparatus, the amount of center axis shake of the rotary stage 103, the amount of deviation of the center of the rotary stage 103 with respect to the observation center, the amount of deviation of the sample wafer center with respect to the center of the rotary stage 103, The amount of deviation of the processed fine pattern with respect to the sample wafer is calculated by the control computer 104, and correction is performed when the calculated information is converted into two rotating coordinate systems for positioning.

1 is an overall system schematic configuration diagram of a charged particle beam apparatus according to an embodiment of the present invention. It is conversion explanatory drawing to the stage coordinate system of the biaxial rotation stage mechanism from a wafer coordinate system. It is explanatory drawing of the example at the time of setting an inspection mechanism installation margin large. It is an explanatory view of the configuration when the configuration is expanded to R ₁ = R ₂ . It is explanatory drawing of rotation center axis | shaft blurring. It is explanatory drawing of rotation stage rotation center deviation measurement with respect to an observation center. It is explanatory drawing of wafer center shift | offset | difference measurement with respect to a rotation stage rotation center. It is explanatory drawing of the corresponding | compatible relationship between the attachment position of an inspection mechanism etc. which were shown in FIG. 3, and an inspection mechanism. It is a block diagram of the process part which performs the positioning process of the biaxial rotation stage in one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Sample chamber, 102 ... Rotary arm, 103 ... Rotary stage, 104 ... Control computer, 105 ... Man-machine interface, 106 ... Memory | storage device, 107 ... Input device, DESCRIPTION OF SYMBOLS 108 ... Wafer transfer unit, 109 ... Wafer transfer robot, 110 ... Gate valve, 111 ... Load port, 112 ... Pod, 201 ... Wafer coordinate system, 202 ... Stage coordinate System, 203 ... inspection mechanism installation position, 204 ... rotation arm rotation center, 205 ... rotation stage rotation center, 206 ... inspection mechanism attachment position margin, 207 ... outside observation impossible area, 208 , 301 to 303, 401 to 403... Inspection mechanism installation position, 304 to 306... Margin, 307. 308... Neutralization device mounting position, 309, 404... Outer peripheral dedicated inspection mechanism mounting position, 501... Stage center mark locus accompanying rotation, 502 503. X, Y), 504..., Deviation amount of rotation amount, 601... Rotation stage rotation center with respect to the visual field center, 602... S ₁ rotation stage rotation center after adjustment, 603. Deviation amount, 701 ... V-shaped notch position in the screen, 702 ... Wafer center deviation amount, 801 ... Wafer coordinate system → polar coordinate conversion processing unit, 802 ... Polar coordinate → biaxial rotation stage coordinate Deformation processing unit, 803... Wafer center deviation data, 804... Wafer center deviation data, 805... 806... Rotation amount deviation amount data 807... Stage center shift (X, Y) data accompanying rotation, 808... Input coordinates, 809... Inspection mechanism designation, 810.・ Each inspection mechanism mounting position (rotating arm angle), 901... Optical inspection device, 902... Optical microscope, 903... Charged particle beam inspection device, 904. Equipment, 906 ... Peripheral inspection mechanism

Claims (10)

In a charged particle beam apparatus that inspects an inspection object by irradiating the inspection object with a charged particle beam,
A rotating stage on which the object to be inspected is arranged and rotates the object to be inspected;
Means for rotationally driving the rotary stage;
A rotating arm that supports the rotating stage and moves it in an arc;
Means for driving the rotating arm;
A charged particle beam inspection means for inspecting the inspection object by irradiating the inspection object disposed on the rotary stage with charged particles;
In order to move the inspection position of the inspection object placed on the rotary stage to the position where the charged particle beam from the charged particle beam inspection means is irradiated, the rotation angle of the rotary arm and the rotation of the rotary stage And a control means for driving the rotation arm driving means and the stage rotation driving means based on the calculated rotation angle,
With
The inspection position of the inspection object is indicated by orthogonal coordinates with respect to the inspection object, and the control means converts the inspection position indicated by the orthogonal coordinates into a polar coordinate position with reference to the rotating arm. And calculating the rotation angle of the rotary arm and the rotation angle of the rotary stage for moving the converted inspected position to a position irradiated with the charged particle beam from the charged particle beam means,
The control means uses the deviation between the observation center of the charged particle beam inspection means and the rotation center of the rotation stage, and the deviation between the rotation center of the rotation stage and the center position of the object to be inspected. And a rotation angle of the rotary stage is calculated . The charged particle beam apparatus according to claim 1, wherein the rotation radius R ₁ of the rotating _arm, for the minimum necessary rotation angle of the rotating arm resulting from the rotation radius R ₂ of the rotary stage, the rotation angle margin at least twice The charging is provided, provided with an arrangement position margin of the inspection object with respect to the rotary stage and an installation position margin of the inspection mechanism, and inspecting the inspection object on a general circumference along a movement locus of the rotation arm. A charged particle beam apparatus, comprising at least three inspection means including a particle beam inspection means. 3. The charged particle beam apparatus according to claim 2 , wherein one of the inspection means is a low-magnification optical microscope, and the optical microscope is arranged at a center on a general circumference along a movement locus of the rotary arm. And a charged particle beam apparatus for inspecting an outer peripheral portion of the inspection object. 3. The charged particle beam apparatus according to claim 2 , wherein a surface electric field measuring device and a static eliminator are arranged at an arbitrary margin of the inspection means mounting position on the approximate circumference. The charged particle beam apparatus according to claim 2, wherein the rotation of the rotating arm radius R ₁ substantially equal to the rotation radius R ₂ of the rotary stage, the outer peripheral inspection means on a schematic circumferentially along the moving locus of the rotary arm A charged particle beam device characterized by comprising: 3. The charged particle beam apparatus according to claim 2 , wherein a mark indicating the rotation center of the rotary stage is displayed on the rotary stage, the inspection object is a semiconductor wafer, and storage means for storing design data of the semiconductor wafer The control means detects the axial blur of the rotary stage mechanism by tracking and detecting the center mark simultaneously with the rotation of the rotary stage, and shifts the observation center and the rotation center of the rotary stage at the arrangement position of each inspection means. Using the low magnification optical microscope installed at the inspection means mounting position, the amount of misalignment between the direction in which the semiconductor wafer is placed, the rotation center of the rotary stage, and the center of the semiconductor is detected. Alignment marks included in three points on the diameter including the vicinity of the semiconductor wafer center are determined, and the marks are used at high magnification. Marks, to detect the deviation amount of the pattern to the semiconductor wafer by detecting the charged particle beam apparatus characterized by controlling the operation of the rotary arm and the rotary stage in accordance with the information of the observation position specified for each test unit. 7. The charged particle beam apparatus according to claim 6 , wherein a semiconductor chamber as an object to be inspected is carried from the sample chamber into the sample chamber in which the rotary stage and the rotary arm are disposed, and the sample chamber is carried out of the sample chamber. And the control means stores in the storage means position information when the semiconductor wafer is carried into the rotary stage, and based on the position information stored in the storage means when the semiconductor wafer is unloaded. A charged particle beam apparatus for reproducing the position of the semiconductor wafer. 7. The charged particle beam apparatus according to claim 6, wherein the control means stores a pattern shift amount with respect to the semiconductor wafer in the storage means in association with the design data of the semiconductor wafer, and when the semiconductor wafer is inspected by the same design information, Charged particle beam device characterized by reusing In the inspection method of the inspection object using the charged particle beam device,
Place the object to be inspected on the rotary stage,
The rotary stage is supported on a rotary arm that moves the rotary stage in an arc shape,
A charged particle beam inspection means for inspecting the inspection object by irradiating the inspection object disposed on the rotating stage with charged particles,
The inspection position indicated by the orthogonal coordinates with respect to the inspection object is converted into a polar coordinate position with the rotation arm as a reference, and the converted inspection position is irradiated with the charged particle beam from the charged particle beam means. The rotation angle of the rotary arm and the rotation angle of the rotary stage for moving to the position to be moved are shifted between the observation center of the charged particle beam inspection means and the rotation center of the rotary stage, and the rotation center of the rotary stage. And the rotational position of the rotary stage, and based on the calculated rotation angle of the rotary arm and the rotation angle of the rotary stage , the rotation arm driving means and the stage rotation driving means are An inspection method for an object to be inspected using a charged particle beam device characterized by being driven. 2. The charged particle beam apparatus according to claim 1, wherein the control means detects a rotation center mark on the rotary stage, tracks and detects the center mark simultaneously with the rotation of the rotation stage, and stores an axial shake amount of the rotation stage from the result. The center of rotation mark is detected at the mounting position of the inspection means, and the deviation amount between the observation center and the rotary stage is stored from the result, and the notch position of the sample is measured using the mounting position of the inspection means or a low magnification optical microscope. And the position of the sample, the rotation center of the rotary stage, and the deviation amount of the sample center are stored, and the information on the observation designated position for the inspection means is stored in the rotary stage from the stored data group. The charged particle beam apparatus is characterized in that it is changed to a control amount by a rotary arm and a rotary stage.

Images