JP2012033594A - Substrate holder and substrate conveying system - Google Patents

Abstract

Even when a substrate of a different size is mounted as an observation sample on a substrate holder having the same external dimensions, regardless of the substrate mounted, it is possible to accurately detect whether the substrate is not mounted or abnormally mounted. Let it be detected.
A tilt detection pin 51 on which an abnormally mounted wafer 2S rides is erected on a non-specified area portion Q other than the specified area portion P where a wafer 2S is normally placed on a holder 50, and the abnormal mounting is performed. The posture state of the wafer 2S thus made is changed to a posture state that can be detected by the wafer tilt sensor 47 that detects abnormal mounting of the wafer 2 on the holder 50.
[Selection] Figure 10

Description

  The present invention is applied to a scanning electron microscope with a length measurement function used in a semiconductor element or integrated circuit inspection process or the like, and holds a substrate to be inspected and transports it as an observation sample to a sample chamber And a substrate transfer system.

  In the manufacturing process of semiconductor elements and integrated circuits, inspection and evaluation of semiconductor elements and integrated circuits created on a wafer are performed by measuring dimensions such as line widths of various patterns formed on the wafer. Usually, a scanning electron microscope (SEM) with a length measuring function called a length measuring SEM or a CD-SEM (critical dimension SEM) is used for measuring such a minute dimension.

  The length measurement SEM obtains an observation sample image by imaging the emission signal of secondary electrons and the like obtained by irradiating the observation sample with a charged particle beam such as an electron beam or an ion beam. The shape of the pattern is discriminated from the change of the pattern and the dimensions such as the pattern line width are derived. At that time, a wafer as an observation sample is transferred to a sample chamber held in a vacuum state by a substrate transfer system (substrate transfer system) provided in the length measurement SEM, and charged on a sample stage in the sample chamber. Receives particle beam irradiation.

  When performing wafer observation and length measurement using a length measurement SEM, a wafer to be inspected is stored in advance in a case capable of storing one or a plurality of wafers called a pod and prepared for observation. When performing observation and length measurement, wafers are taken out from the pod one by one and transported to an atmospheric pressure chamber called a load lock chamber of the length measurement SEM and a vacuum state, and the atmosphere is vacuumed. Then, the sample is transported to the sample chamber, and the above-described observation and length measurement are performed. The wafer that has been observed and measured is once transported from the sample chamber to the load lock chamber, the atmosphere is adjusted to atmospheric pressure, taken out from the load lock chamber, and transported back to the pod.

  In wafer inspection and evaluation using a length measurement SEM, such observation and length measurement operations are repeated for each wafer and the number of wafers to be inspected stored in the pod. At that time, a robot is usually used to transfer the wafer between the pod and the load lock chamber of the length measuring SEM. The robot carries the wafer to be inspected taken out of the pod to a wafer holder called a holder provided in the load lock chamber of the length measurement SEM each time the length measurement SEM is observed and measured. Mounted at the specified position. The holder is held by a leaf spring in the load lock chamber, and is configured to move between the sample stage in the sample chamber in response to the operation of an arm provided in the load lock chamber. On the surface of the holder, a fixed pin and a movable pin for holding the wafer at a predetermined position are erected at an interval. The wafer mounted at a predetermined position of the holder is pressed against the fixed pin by this movable pin and held at the predetermined position.

  The load lock chamber is connected to the suction side of the dry pump via a valve in order to make the atmosphere in an atmospheric pressure state for transferring the wafer between the pod and the vacuum chamber the same as the sample chamber. In the length measurement SEM, when the mounting of the wafer at the specified position of the holder is completed, the load lock chamber is sealed, and the chamber is evacuated by communicating with the suction side of the dry pump by opening the valve described above. Then, when the load lock chamber reaches a specified vacuum level, the space between the load lock chamber and the sample chamber is opened, and the wafer is transferred from the load lock chamber to the sample chamber together with the holder, and charged particle beams are transferred inside the sample chamber. Receive irradiation.

  Further, the load lock chamber is provided with a sensor for detecting the presence or absence of a wafer and abnormal loading on the holder. In the length measurement SEM, when a wafer is not loaded or abnormally loaded, systemization such as stopping the transfer of the holder on which the wafer is loaded to the sample chamber is being implemented.

  As a substrate transport system for such a length measurement SEM, Patent Document 1 discloses that a light beam is irradiated toward each of the upper surface and the lower surface of the wafer held by a holder and reflected on the upper surface and the lower surface of the wafer, respectively. And a wafer holding state confirmation system that determines whether the holding state of the wafer is normal or not depending on whether the light beam reflected by the upper surface and the lower surface is received by the light receiver. Has been.

JP-A-9-64155

  In the inspection process of semiconductor elements and integrated circuits using the length measurement SEM as described above, a wafer having a size smaller than the normal observation specification size wafer by the length measurement SEM can be observed. Similar to length measurement, there is a demand for observation and length measurement with the same device.

  In order to meet this requirement, the arrangement positions of the fixed pins and movable pins on the holder surface for holding the wafer in a predetermined position of the holder are usually smaller than the normal observation specification size by the length measuring SEM. In many cases, a holder that has been changed in accordance with a predetermined wafer size is prepared separately, and when the size of the wafer to be inspected changes, the holder is replaced.

  In the case of this separately prepared holder, the fixed pin and the movable pin for holding the holder at a prescribed position are arranged on the surface of the holder along the outer periphery of a predetermined wafer smaller than the observation specification size of the length measurement SEM. Placed in. However, the external dimensions of this separately prepared holder are the same as the wafer size of the observation specification because the configuration itself of the substrate transfer system that transfers the entire holder on which the wafer is mounted is the same between the load lock chamber and the sample stage in the sample chamber. The same as the outside dimensions of the holder. In addition, the configuration and arrangement of the sensor for detecting the presence or absence of a wafer provided in the load lock chamber and the abnormal loading in the holder remain the same.

  Therefore, in a holder that has been changed according to a predetermined wafer size smaller than the normal observation specification size of this length measurement SEM, the area other than the normal wafer mounting area defined by the fixed pin and the movable pin on the surface of the holder, It is larger than the case of a holder that matches the normal observation specification size of a length measurement SEM.

  On the other hand, the configuration and arrangement of sensors for detecting the presence or absence of a wafer and abnormal loading on the holder is because the wafer to be inspected becomes smaller and the normal mounting area (specified area) on the surface of the holder becomes smaller. In the case of an observation specification size wafer, the presence or absence of a wafer or abnormal loading in a holder can be detected, but in the case of a small predetermined wafer, the presence or absence of a wafer or abnormal loading in a holder may not be detected. There is.

  The detected environment changes in this way, and in particular, the area other than the normal wafer mounting area (non-regulated area) is enlarged. It is necessary to have a mechanism that can detect an abnormal mounting or the like based on the output of the same sensor without changing.

  The present invention has been made in view of the above-described problems. Even when a substrate of a different size is mounted as an observation sample on a substrate holder having the same outer dimension, the present invention is concerned with the difference in the mounted substrate. It is an object of the present invention to provide a substrate holder and a substrate transport system that allow a sensor to accurately detect whether a substrate is not mounted or abnormally mounted.

  In order to solve the above-described problems, the present invention has a pin-up arrangement in which an abnormally mounted board rides on a non-regulated area other than a prescribed area where a board is normally placed on a holder as a board holder. Then, the posture state of the abnormally mounted substrate is changed to a posture state that can be detected by a sensor that detects abnormal mounting of the substrate in the holder.

  In addition, the pins are erected on the holder in the non-specified area portion within the size of the substrate from the inner wall of the space where the holder is arranged, and further, the pins stand in the non-specified area portion around the outer periphery of the specified area portion. The interval between the adjacent pins arranged is within the size of the substrate.

  According to the present invention, it is possible to reliably detect abnormal mounting of a substrate as a sample even if a substrate smaller than a substrate having an observation specification size that is normally transported is transported.

It is the schematic block diagram which looked at one Example of length measurement SEM to which the board | substrate holder and board | substrate conveyance system which concern on this Embodiment were applied from the upper direction. It is a partial cross-sectional top view of a load lock part. FIG. 3 is a partial side sectional view of the load lock portion shown in FIG. 2. It is a partial cross-sectional top view of a load lock part when a wafer is abnormally mounted on a holder. FIG. 5 is a partial side sectional view of the load lock portion shown in FIG. 4. It is a partial cross-sectional top view of a load lock portion provided with a holder for observation and inspection of a sample smaller than a sample having an observation specification size. It is a partial cross-sectional top view of a load lock portion when a wafer is abnormally mounted on a holder for observation and inspection of a sample smaller than a sample having an observation specification size. FIG. 8 is a partial side sectional view of the load lock portion shown in FIG. 7. It is a partial cross-sectional top view of a load lock portion provided with a holder for observation and inspection of a sample smaller than a sample having an observation specification size. It is explanatory drawing of the 1st example of arrangement | positioning of the pin for inclination detection. It is explanatory drawing of the 2nd example of arrangement | positioning of the pin for inclination detection. It is explanatory drawing of the 3rd example of arrangement | positioning of the pin for inclination detection. It is explanatory drawing of the 4th example of arrangement | positioning of the pin for inclination detection. It is another explanatory drawing of the 4th example of arrangement | positioning of the pin for inclination detection. It is a partial cross-sectional top view of the load lock part of the abnormal loading state of the wafer in the holder which concerns on this Embodiment, and the substrate conveyance system using the same. FIG. 16 is a partial side cross-sectional view of the load lock portion illustrated in FIG. 15.

  An embodiment of a substrate holder and a substrate transport system according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an example of a length measuring SEM to which a substrate holder and a substrate transfer system according to the present embodiment are applied as viewed from above.

  The length measurement SEM 1 includes a mini-environment sample transport apparatus 10 and a scanning electron microscope main body 20. The mini-environment method means that a local space or environment having a predetermined cleanliness is provided. The length measuring SEM 1 controls various operations including sample transport, sample observation, and measurement by an attached computer device (not shown). An operator uses a user interface such as an OSD (On Screen Display) displayed on the screen of a mouse, keyboard, or display device of a computer device to give instructions on control processing such as sample transportation to be executed by the length measurement SEM1. Perform setting input and the like to the computer device.

  In the illustrated example, the sample transport apparatus 10 includes two load ports 11 (11a and 11b) and one sample transport robot 12. The load port 11 is mounted with a wafer storage case 13 for transporting and storing the wafer 2 such as an open cassette or FOUP (Front-Opening Unified Pod) by an apparatus operator or AGV (Automatic Guided Vehicle). The load port 11 is provided with a mechanism for controlling the opening and closing of the lid or the door, such as FOUP, for mounting a pod that can maintain airtightness in the case by the lid or the door. The sample transport robot 12 takes out the wafer 2 from the wafer storage case 13 mounted on the load port 11 and transports the wafer 2 to one of the two load lock chambers 24 of the scanning electron microscope main body 20. The wafer 2 is taken out from 24, stored in the wafer storage case 13, and returned.

  In the sample transport device 10, it is necessary to locally increase the degree of cleanliness of the portion where the wafer 2 is transported, so that the entire device is covered with the mini-environment sample transport mechanism 14. The mini-environment type sample transport mechanism 14 includes an FFU (Fan Filter Unit). Inside the mechanism, air having a high degree of cleanness is supplied through the FFU in a positive pressure state than the atmospheric pressure atmosphere outside the mechanism.

  The scanning electron microscope main body 20 has a configuration in which a load lock portion 21, a stage portion 22, and a lens barrel portion 23 are integrally provided. The load lock portion 21 is provided with a pair of load lock chambers 24 (24a, 24b) as an atmosphere conversion chamber between an atmospheric pressure state and a vacuum state. The stage unit 22 is provided with a sample chamber 25 which is held in a vacuum state for irradiating the wafer 2 with charged particle beams, and a sample stage 29 on which a holder 26 on which the wafer 2 is mounted is conveyed in the sample chamber 25. Is provided. Each load lock chamber 24 is communicated / blocked corresponding to the opening / closing of the load door 34 interposed between the inside of the mini-environment type sample transport mechanism 14 in which the sample transport robot 12 is arranged, The sample chamber 25 of the stage unit 22 is communicated and blocked corresponding to the opening and closing of the gate valve 35 interposed therebetween. Each load lock chamber 24 is sealed with respect to the inside of the mini-environment type sample transport mechanism 14 and the sample chamber 25 by closing the load door 34 and the gate valve 35.

  A charged particle source (not shown) that generates a charged particle beam and a charged particle beam generated by the charged particle source are converged and deflected on the lens barrel 23 and mounted on a sample stage 29 in a sample chamber 25. And an electron optical system (not shown) for irradiating the wafer 2. Further, the lens barrel part 23 or the stage part 22 is provided with a detector (not shown) for detecting emitted charged particles emitted from the sample by irradiation with a charged particle beam in order to acquire an observation sample image. Further, in the load lock chamber 24, a chamber opened to the atmospheric pressure atmosphere by the sample transfer with the sample transfer device is brought into the same vacuum state as the sample chamber 25 of the stage unit 22, so that a valve (not shown) is provided. Connected to the suction side of the dry pump.

  In the length measuring SEM 1 configured as described above, when the wafer storage case 13 is mounted on the load port 11 by an apparatus operator or AGV, the wafer 2 to be inspected stored in the wafer storage case 13 is transferred to the sample transport robot 12. And is transferred to the load lock chamber 24 through the opened load door 34 and mounted at a predetermined position of the holder 26 disposed in the load lock chamber 24. When the loading of the wafer 2 into the holder 26 is completed, the load lock chamber 24 closes the load door 34 and seals the chamber opened along with the loading of the wafer 2 by the sample transport robot 12 to the outside. A valve provided between the pump and the dry pump is opened, and vacuuming is performed by the indoor dry pump.

  When the load lock chamber 24 reaches a predetermined degree of vacuum by evacuation, the valve between the dry pump is closed and evacuation by the dry pump is stopped, and is provided between the sample chamber 25 of the stage 22. The gate valve 35 is opened and the wafer 2 is transported together with the holder 26 into the sample chamber 25, and the wafer 2 is mounted together with the holder 26 on the sample stage 29. The wafer 2 mounted on the sample stage 29 is irradiated with a charged particle beam and is observed and measured.

  After completion of the inspection, the wafer 2 mounted on the sample stage 29 in the sample chamber 25 together with the holder 26 is transferred from the sample chamber 25 to the load lock chamber 24 via the gate valve 35 opened to the load lock chamber 24. It is conveyed in and returned. Then, after closing the gate valve 35 between the sample chamber 25 and closing the load lock chamber 24 with respect to the sample chamber 25, the load lock chamber 24 is opened to atmospheric pressure, and the degree of vacuum is lowered. When the load lock chamber 24 reaches atmospheric pressure, the load door 34 is opened, and the wafer 2 that has been inspected is transferred from the load lock chamber 24 to the wafer storage case 13 where the wafer 2 on the load port 11 is taken out. Returned and stored by the robot 12.

  Next, a detailed configuration of the load lock unit 21 including the load lock chamber 24 and mounting of the wafer 2 on the holder 26 in which the load lock chamber 24 is arranged will be described in detail with reference to FIGS.

  2 is a partial cross-sectional top view of the load lock portion, and FIG. 3 is a partial side cross-sectional view of the load lock portion shown in FIG.

  In the illustrated example, the load lock portion 21 includes a rectangular parallelepiped hollow casing 31, and the hollow portion forms a load lock chamber 24. In the figure, X is the width direction of the casing 31 and the load lock chamber 24, Y is the length direction of the casing 31 and the load lock chamber 24, and Z is the height direction of the casing 31 and the load lock chamber 24. Show. Here, the length direction Y of the casing 31 is the same as the transfer direction of the holder 26 disposed in the load lock chamber 24 with respect to the sample chamber 25 of the stage unit 22, A load door 34 that opens the load lock chamber 24 when the wafer 2 is transferred between the port 11 and the load lock chamber 24, and a load lock when the wafer 2 is transferred between the load lock chamber 24 and the sample chamber 25. A gate valve 35 that communicates the chamber 24 with the sample chamber 25 is provided.

  In addition, columnar members 32R and 32L having a rectangular cross section extend along the length direction Y of the casing 31 on both sides in the width direction X on the bottom surface of the inner wall of the casing 31 to constitute the base 32. Each base 32 (32R, 32L) is extended with a rail 33 (33R, 33L) for supporting the holder 26 movably along its length direction Y. Each rail 33 (33R, 33L) engages with a wheel 27 (27R, 27L) rotatably attached to the holder 26, and the holder 26 can be moved along the length direction Y of the load lock chamber 24. I support it. The holder 26 is configured by a plate-like member whose top surface is a rectangular flat mounting surface 28. The holder 26 is held by a leaf spring (not shown) in the load lock chamber 24, and in response to the operation of an arm (not shown), the wheel 27 rolls on the rail 33, and the inside of the sample chamber 25. It is configured to be movable with respect to the sample stage 29.

  On the other hand, the wafer 2 has two fixed pins 41 (41 a, 41 b) and one movable pin 42 erected on the mounting surface 28 of the holder 26 with respect to the holder 26 arranged in the load lock chamber 24. And is fixed by positioning. The two fixed pins 41 and the one movable pin 42 are arranged on the mounting surface 28 of the holder 26 so as to be appropriately spaced from each other so that the outer peripheral surfaces thereof circumscribe the thin disc-shaped wafer 2. . A region of the inner mounting surface 28 defined by the two fixed pins 41 and one movable pin 42 corresponds to a defined region portion P of the mounting surface 28 on which the normally mounted wafer 2 faces. . A plurality of support pins 43 (43 a to 43 c) having a height lower than that of the fixed pins 41 and the movable pins 42 for horizontally supporting the wafer 2 to be positioned and mounted are provided in the specified region portion P of the mounting surface 28. It is erected. The wafer 2 mounted on the defined area portion P of the mounting surface 28 is horizontally supported by the plurality of support pins 43 and is pressed against the fixed pins 41 by the movable pins 42 and held.

  In the case of the holder 26 shown in FIGS. 1 and 2, the fixed pins 41, the movable pins 42, and the support pins 43 are arranged in an observation specification size wafer that matches the observation specification size of the length measurement SEM, for example, a 12 inch wafer 2L. Is configured as an inspection target. In addition, the size (width and length) of the holder 26 itself is such that the 12-inch wafer 2L does not protrude, and accordingly, the size of the load lock chamber 24 and the rails 33 (33R, 33L). ) Etc. also correspond to the size of the holder 26.

  In addition, the load lock unit 21 is provided with a 12-inch wafer 2L on the holder 26 on the assumption that the holder 26 is used for observation inspection of a 12-inch wafer 2L having an observation specification size of the length measurement SEM1. A wafer presence / absence sensor 46 that detects absence and a plurality of wafer tilt sensors 47 (47a, 47b) that detect an abnormal placement state of the 12-inch wafer 2L on the holder 26 are provided.

  The wafer presence / absence sensor 46 and the wafer tilt sensor 47 are used for the transfer accuracy of the holder 26 arranged in the load lock chamber 24 to the specified position by the sample transfer robot 12, the displacement of the movable pin 42 provided in the holder 26, or The wafer 2L may not be normally placed at the specified position of the holder 26 due to vibrations of the sample transfer device 10 itself, and such an abnormal state is detected based on the output of each sensor. To do.

  Each of the sensors 46 and 47 has a light beam emitting part 46D, which is provided on one of a pair of rails 33 (33R and 33L) of the load lock part 21 with its orientation and height adjusted via mounting bases 36a and 37a. 47D (47Da, 47Db) and the other one of the pair of rails 33 (33R, 33L) have their orientation and height through the mounting bases 36b, 37b so as to receive the light beams emitted from the light emitting portions 46D, 47D. Light receiving portions 46I and 47I (47Ia and 47Ib) provided in an adjusted manner.

  In the wafer presence / absence sensor 46, a light emitting unit 46D and a light receiving unit 46I are arranged so that the optical axis path is shielded on the way by the 12-inch wafer 2L mounted on the holder 26. In the illustrated example, the wafer presence / absence sensor 46 is disposed so that the optical axis path extends along the width direction X at the center portion in the length direction Y of the specified region of the mounting surface 28.

  On the other hand, the wafer tilt sensor 47 (47a, 47b) is normally mounted on the holder 26 of the 12-inch wafer 2L (the 12-inch wafer 2L includes two fixed pins 41 and one movable pin 42). In the mounting state in which the positioning is fixed and supported by any of the plurality of support pins 43), the light emitting unit 47D (47Da, 47Db) and the light receiving unit 47I (47Ia) are arranged so that the optical axis path is not shielded by the wafer 2L. , 47Ib).

  In the illustrated example, in the wafer tilt sensor 47, the light emitting portion 47D and the light receiving portion 47I have a height position along the upper surface that is slightly higher than the upper surface of the wafer 2L on which the optical axis path between them is normally mounted. It arrange | positions so that it may extend without shading. Further, the wafer tilt sensors 47a and 47b are arranged so that the optical axis passages are located on the opposite sides of the length direction Y of the holder 26 with the optical axis passage of the wafer presence sensor 46 interposed therebetween. . In addition, the optical axis passages of the wafer tilt sensors 47a and 47b are arranged so that the mounting positions of the light emitting part 47D (47Da, 47Db) and the light receiving part 47I (47Ia, 47Ib) are holders in order to increase the respective detection ranges. 26 is shifted in the longitudinal direction Y, and each optical axis passage is inclined with respect to the width direction X.

  In the sample presence / absence sensor 46 and the wafer tilt sensor 47 configured as described above, in the sample transport apparatus 10, when the optical axis of the wafer presence / absence sensor 46 is shielded, the wafer 2L is mounted on the holder 26. If the light is not shielded, it is determined that the wafer 2L is not loaded in the holder 26.

  Similarly, in the sample transport apparatus 10, when the optical axis of any wafer tilt sensor 47 is not shielded, it is determined that the wafer 2 </ b> L is normally mounted in the holder 26 and any wafer tilt sensor 47. When the optical axis is shielded, it is determined that the wafer 2L is abnormally mounted in the holder 26.

  2 and 3 correspond to a partial cross-sectional top view and a partial side cross-sectional view of the load lock portion 21 when the wafer 2L is normally mounted on the holder 26, respectively.

  As shown in FIGS. 2 and 3, the wafer with respect to the holder 26 which is positioned and fixed by two fixed pins 41 and one movable pin 42 and supported by any of the plurality of support pins 43. At the time of normal mounting of 2L, it is determined that “the wafer 2L is mounted on the holder 26” based on the output of the wafer presence sensor 46 whose optical axis is shielded. Based on the outputs of 47b, it is determined that “the wafer 2L is normally mounted on the holder 26”.

  On the other hand, when the wafer 2L is abnormally mounted on the holder 26 as shown in FIGS. 4 and 5, the wafer 2L on the holder 26 is abnormal based on the output of at least one shielded wafer tilt sensor 47a, 47b. It is judged that it is mounted on.

  4 and 5 show a partial cross-sectional top view and a partial side cross-sectional view of the load lock portion when the wafer is abnormally mounted on the holder.

  In the example shown in FIGS. 4 and 5, since the wafer 2L rides on the top surface of the movable pin 42 and is separated from the support pin 43c and is not supported, the wafer 2L has two fixed pins 41 and one movable pin. 42 shows an abnormal mounting state in which it is mounted with an inclination with respect to the holder 26 without being positioned and fixed.

  In the length measurement SEM 1 shown in FIG. 1, when the wafer 2L taken out from the wafer storage case 13 of the load port 11 is transported to the load lock chamber 24, the regulation of the holder 26 in which the wafer 2L is arranged in the load lock chamber 24 is specified. The vacuum degree of the load lock chamber 24 is adjusted only when it is confirmed that it is normally mounted at the position, and the wafer 2 is transferred into the sample chamber 25 of the scanning electron microscope main body 20 together with the holder 26. It is designed to be mounted on the sample stage 29. Similarly, when the wafer 2 mounted together with the holder 26 on the sample stage 29 in the sample chamber 25 is transferred into the load lock chamber 24 and returned after the inspection is completed, the wafer presence sensor 46 and the wafer are similarly measured. The tilt sensor 47 can confirm whether or not the state in which the wafer 2L is normally mounted at the specified position of the holder 26 is maintained.

  By the way, in the length measurement SEM1 applicable to the 12-inch wafer 2L as the observation specification size of the wafer 2 to be inspected as described above, for example, the 6-inch wafer 2S smaller than the 12-inch wafer 2L of the observation specification size has the observation specification size. The case of observing and measuring with the same apparatus as in the case of observing and measuring the 12-inch wafer 2L will be described.

  In this case, instead of the holder 26 for loading and transferring the 12-inch wafer 2L between the load lock chamber 24 and the sample chamber 25, the holder 30 for loading and transferring the 6-inch wafer 2S is replaced by a rail of the load lock section 21. 33 is attached.

  FIG. 6 is a partial cross-sectional top view of a load lock portion provided with a holder for observation inspection of a sample smaller than a sample having an observation specification size.

  In this case, the arrangement positions of the fixed pins 41 and the movable pins 42 on the mounting surface 28 of the holder 30 are two fixed pins in consideration of detection by the wafer presence sensor 46 and the wafer tilt sensor 47 in the load lock unit 21. 41 (41 a, 41 b) and one movable pin 42 are arranged at an appropriate distance from each other so that the outer peripheral surfaces of the movable pin 42 circumscribe the 6-inch wafer 2 </ b> S having a thin disk shape. Therefore, the area of the inner mounting surface 28 defined by the two fixed pins 41 and one movable pin 42 is a defined area portion of the mounting surface 28 facing the normally mounted 6-inch wafer 2S. The optical axis path of each of the wafer presence sensor 46 and the wafer tilt sensor 47 passes through the specified region portion P of the mounting surface 28. A plurality of support pins having a height lower than the fixed pins 41 (41a, 41b) and the movable pins 42 for horizontally supporting the 6-inch wafer 2S to be positioned and mounted on the specified region portion P of the mounting surface 28 43 (43a-43c) is similarly set up. The wafer 2 mounted on the defined area portion P of the mounting surface 28 is horizontally supported by the plurality of support pins 43 and is pressed against the fixed pins 41 by the movable pins 42 and held.

  In this case, since the size of the disk-like member including the mounting surface 28 is the same as that of the 12-inch wafer 2L, the holder 30 is opposite to the amount by which the defined area portion P of the mounting surface 28 is reduced. In the load lock chamber 24, the specified area region Q in the load lock chamber 24 outside the specified area portion P excluding the specified area portion P is enlarged.

  7 and 8 show a partial cross-sectional top view and a partial side cross-sectional view of the load lock portion when the wafer is abnormally mounted in a holder for observation inspection of a sample smaller than the sample of the observation specification size. is there.

  As a result, as shown in FIGS. 7 and 8, the 6-inch wafer 2 </ b> S is detached from the specified region portion P of the mounting surface 28, and is directly mounted on the mounting surface 28 of the holder 30 in the outside specified region region Q. In the abnormally mounted state that has been placed, the wafer tilt sensor 47 (47a, 47b) is not shielded by the wafer 2S in the respective optical axis paths. Therefore, the sample transport apparatus 10 determines that “the wafer 2S is normally mounted on the holder 30” based on the output of the wafer tilt sensor 47 (47a, 47b). In this abnormal state, the wafer 2S in the abnormal mounting state cannot shield the optical axis path of the wafer presence sensor 46. Therefore, the sample transport apparatus 10 determines that “the wafer 2S is not mounted on the holder 30” based on the output of the wafer presence sensor 46.

  In FIG. 7, as indicated by a two-dot chain line, the wafer 2S rides only on the top surface of the movable pin 42, and the wafer 2S has two fixed pins 41 (41a, 41b) and a plurality of support pins 43 (43a). ˜43c), when the wafer tilt sensor 47 (47a, 47b) is mounted on the wafer 2S when the wafer tilt sensor 47 is mounted outside the specified area Q in the load lock chamber 24 without contacting any of the wafer 2S. However, the optical axis path of the wafer presence / absence sensor 46 may be shielded by the wafer 2S tilted in the length direction Y of the load lock chamber 24. In this case, in the sample transport apparatus 10, it is determined that “the wafer 2S is mounted on the holder 30” based on the output of the wafer presence / absence sensor 46, and the outputs of the wafer tilt sensors 47a and 47b, both of which are not shielded from light. Based on the above, it is determined that “the wafer 2S is normally mounted on the holder 30”. As a result, the sample transport apparatus 10 transports the holder 30 to the sample chamber 25 of the scanning electron microscope main body 20, so that the abnormally mounted wafer 2 </ b> L is damaged by the movement of the holder 30 at that time.

Therefore, the sample of the observation specification size shown in FIG. 9 (for example, 12-inch wafer 2L)
In a holder 50 for observation and inspection of a smaller sample (for example, 6-inch wafer 2S), a non-regulated area portion Q of the mounting surface 28 of the holder 50 is set based on the outputs of the wafer tilt sensors 47a and 47b. In order to prevent the sample transport apparatus 10 from determining that the wafer 2S is normally mounted on the holder 50, an inclination detection pin 51 that holds the posture of the wafer 2S abnormally mounted in the non-regulated area portion Q is provided. Has been placed.

  An embodiment of the holder 50 in which the inclination detection pins 51 are arranged will be described with reference to the drawings. In the description, the same or similar components as those of the holders 26 and 30 described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 9 is a partial cross-sectional top view of a load lock portion provided with a holder for observation and inspection of a sample smaller than the sample of the observation specification size provided with the tilt detection pin.

  In FIG. 9, a holder 50 is for observation inspection of a wafer 2 (for example, 6-inch wafer 2S) smaller than a wafer 2 (for example, 12-inch wafer 2L) having an observation specification size. In the holder 50, the size of the plate-like member including the mounting surface 28 itself is the same as that of the 12-inch wafer 2L. Inside, the non-regulated area portion Q in the load lock chamber 24 outside the defined area portion P excluding the defined area portion P is enlarged.

  When the 6-inch wafer 2S is abnormally mounted on the mounting surface 28 of the holder 50 included in the non-regulated area portion Q in the load lock chamber 24, deviates from the non-regulated area portion Q in the load lock chamber 24. In addition, an inclination detection pin 51 is erected to place the wafer 2S in a mounting state in which the optical axis path of the wafer inclination sensor 47 (47a, 47b) is always shielded.

  The tilt detection pin 51 tilts the wafer 2S on the mounting surface 28 when the 6-inch wafer 2S, whose height is equal to or higher than the height of the support pins 43 (43a to 43c), rides on the top thereof. The optical axis path of the wafer tilt sensor 47 (47a, 47b) is shielded from light at the tilted portion.

  Next, the arrangement of the tilt detection pins 51 on the placement surface 28 of the holder 50 corresponding to the non-regulated area portion Q in the load lock chamber 24 will be described.

FIG. 10 is an explanatory diagram of a first arrangement example of the inclination detection pins.
First, as a precondition, when the 6-inch wafer 2S is likely to be abnormally mounted in the non-regulated area portion Q in the load lock chamber 24, the tilt detection pin 51 is loaded on the wafer tilt sensor 47a, 47b is disposed in the non-regulated region portion Q so as to intersect any one of the optical axis paths 47b.

In particular,
1) The inclination detection pin 51 is within the diameter circle of the small diameter wafer 2S contacting the inner wall of the load lock chamber 24, and is separated from the inner wall of the load lock chamber 24 by a radius of the small diameter wafer 2S or more. The optical axis path of the wafer tilt sensor 47 (47a, 47b) is erected and arranged so as not to block the optical axis path of the wafer tilt sensor 47 (47a, 47b) in the non-regulated region portion Q (shaded portion in FIG. 10).
2) Another inclination detection pin 51 adjacent to the one inclination detection pin 51 along the outer periphery of the defined region portion P is the small-diameter wafer 2S in contact with the one inclination detection pin 51. The optical axis passage of the wafer tilt sensor 47 (47a, 47b) is erected and arranged so as not to shield itself in the non-regulated region portion Q in the diameter circle.
3) The tilt detection pin 51 is defined when a part of the non-regulated area portion Q is in contact with or overlaps with the defined area portion P on which the small-diameter wafer 2S on the mounting surface 28 in the load lock chamber 24 is mounted. It is arranged so as to circumscribe the region portion P, and serves also as a fixed pin 41 (41a, 41b) or a movable pin 42 for positioning and fixing the wafer 2S with respect to the specified region portion P.
It is like that.

  In the example shown in FIG. 10, the inclination detection pin 51 includes pins 51 a to 51 f, and the inclination detection pins 51 b and 51 f also serve as fixed pins 41 a and 41 b, and the inclination detection pin 51 c is a movable pin. 42.

FIG. 11 is an explanatory diagram of a second arrangement example of the inclination detection pins.
As shown in FIG. 11, in the first arrangement example of the inclination detection pins shown in FIG. 10, the pins 51 a, 51 c, 51 d, and 51 e are small-diameter wafers that are in contact with two adjacent sides of the inner wall of the load lock chamber 24. The non-regulated region portion Qt in the load lock chamber 24 within the diameter circle of 2S and separated from each adjacent inner wall of the load lock chamber 24 by the radius of the small diameter wafer 2S (the shaded portion in FIG. 11) ) Are arranged avoiding the optical path of the defined area portion P and the wafer tilt sensor 47 (47a, 47b).

  Regarding the pins 51 a, 51 c, 51 d, 51 e arranged in the non-regulated region portion Qt corresponding to the corner portion of the load lock chamber 24, the diameter of the small diameter wafer 2 </ b> S in contact with only one side of the inner wall of the load lock chamber 24. An inclination detection pin 51 arranged in a non-regulated region portion Qu (shaded portion in FIG. 11) in the load lock chamber 24 which is within a circle and is separated from the inner wall in contact therewith by a radius of the small diameter wafer 2S or more. It can also serve as.

  In this case, for each of two adjacent sides of the inner wall of the load lock chamber 24, the diameter circles R1, R2 of the small-diameter wafer 2S that contact only the corresponding side of the inner wall of the load lock chamber 24 are arranged in contact with each other. Consider the state shown in FIG.

  In this state, if the inclination detection pin 51 is located in any one of the non-regulated area portion Qut adjacent to the non-regulated area portion Qt, such as the inclination detection pins 51d and 51e, the load lock chamber 24 is used. From the abnormal mounting state of the wafer 2S in contact with two adjacent sides of the inner wall of the wafer to the abnormal mounting state shifted within a predetermined distance along the inner wall of the load lock chamber 24 on one side of the adjacent one by the wafer tilt sensor 51. The mounting state can be detected.

  Further, even if the inclination detection pin 51 is located only in the non-regular area portion Qt, such as the inclination detection pins 51a, 51c, the non-regular area portion Qt, as in the inclination detection pins 51a ′, 51c ′. And the two non-regulated region portions Qu adjacent to each other, by using the inclination detection pins 51, the abnormally mounted state of the wafer 2S in contact with the two adjacent sides of the inner wall of the load lock chamber 24, The abnormal mounting state can be detected by the wafer tilt sensor 51 until the abnormal mounting state shifted to the other side along the inner wall of the load lock chamber 24 within a predetermined distance range.

  In addition, one inclination detection pin 51 (for example, one of the inclination detection pins 51a (51a ′), 51b, 51c (51c ′), 51d, 51e, 51f) arranged around the outer periphery of the defined region portion P (for example, , 51a (51a ′)), another inclination detection pin 51 (for example, 51b or 51f) adjacent to the periphery of the prescribed region portion P is adjacent to one inclination detection pin 51 (for example, 51a (51a (51a ′)). 51a ′)) is located in the non-regulated region portion Q in the diameter circle of the small-diameter wafer 2S in a state of contact.

FIG. 12 is an explanatory diagram of a third arrangement example of the inclination detection pins.
In the example shown in FIG. 12, among the inclination detection pins 51a, 51b, 51c, and 51d that are also located in both the non-regular region portion Qu adjacent to the non-regular region portion Qt, the pins 51a and 51b are respectively fixed. The pin 41 is configured so that the pin 51 c also serves as the movable pin 42.

  Furthermore, as shown in FIG. 12, for each of two adjacent sides of the inner wall of the load lock chamber 24, the diameter circles R1 and R2 of the small diameter wafer 2S contacting only the corresponding side of the inner wall of the load lock chamber 24 are mutually connected. When arranged in contact with each other, if the diameter circles R1 and R2 are also diameter circles R1 and R2 of two adjacent sides of the inner wall of the load lock chamber 24, the inclination detection pin 51 is fixed. In addition to serving as the pin 41 and the movable pin 42, only the four tilt detection pins 51a to 51d can be used.

  Also in this case, in the inclination detection pins 51a to 51d arranged around the outer periphery of the prescribed region portion P, along the outer periphery of the prescribed region portion P with respect to one inclination detection pin 51 (for example, 51a). Another adjacent tilt detection pin 51 (for example, 51b or 51d) is connected to a non-regulated region portion Q in the diameter circle of the small-diameter wafer 2S in contact with the one tilt detection pin 51 (for example, 51a). It is supposed to be located.

FIG. 13 is an explanatory diagram of a fourth arrangement example of the inclination detection pins.
In the example shown in FIG. 13, the diameter circle R3 of one abnormally mounted wafer 2S is separated from the diameter circle R4 of another abnormally mounted wafer 2S, and the non-regulated area portion Qv is interposed therebetween. This relates to an example of the arrangement of the inclination detection pins 51.

  In this case, the diameter circle R3 of the wafer 2S in one abnormally mounted state corresponds to the abnormally mounted state of the wafer 2S in which the diameter circle R3 itself is in contact with two adjacent sides of the inner wall of the load lock chamber 24 in the illustrated example. Therefore, it is within the diameter circle of the small diameter wafer 2S in contact with the two adjacent sides of the inner wall of the load lock chamber 24, and is separated from the adjacent inner wall of the load lock chamber 24 by the radius of the small diameter wafer 2S or more. An inclination detection pin 51 (51e) is erected and arranged in a non-regulated area portion Qt in the load lock chamber 24.

  In addition, an inclination detection pin 51g for the case where the wafer 2S is abnormally mounted in the non-regulated region portion Qv between the separated diameter circle R4 of another abnormally mounted wafer 2S is as follows. Place upright. In the arrangement, the center r5 has a center r5 on a line segment connecting the center r3 of the diameter circle R3 of one abnormally mounted wafer 2S and the center r4 of the diameter circle R4 of another abnormally mounted wafer 2S, Consider another diameter circle R5 of the abnormally mounted wafer 2S in contact with the inclination detection pin 51e. And in the diameter circle R5 of this further abnormally mounted wafer 2S, and in the non-regulated region portion in the load lock chamber 24 which is separated from the inner wall of the load lock chamber 24 by more than the radius of the small diameter wafer 2S, The tilt detection pins 51g are erected and arranged so as to avoid the prescribed region portion P and the optical axis path of the wafer tilt sensor 47 (47a). Then, when the diameter circle R5 of the another abnormally mounted wafer 2S and the diameter circle R4 of the other abnormally mounted wafer 2S are separated from each other, and the non-regulated area portion Qv still remains between them. In the same manner, another new inclination detection pin 51g is erected and arranged.

  In the case of the illustrated example, only one inclination detection pin 51g is newly installed upright, and the inclination for the abnormal mounting state of the wafer 2S of the diameter circle R4 from which the inclination detection pin 51g is separated. The detection pin 51d is also used as a movable pin 42.

FIG. 14 is another explanatory diagram of the fourth arrangement example of the inclination detection pins.
In the example shown in FIG. 14, the center r of the diameter circle R of the abnormally mounted wafer 2 </ b> S is formed along the inner wall of the load lock chamber 24 in order from the inclination detection pin 51 a according to the third arrangement example described above. This shows a configuration in which the inclination is changed up to the inclination detection pin 51g by changing the rectangular locus shown by the one-dot chain line in the figure. In the illustrated example, the tilt detection pin 51b also serves as the movable pin 42, and the tilt detection pins 51e and 51g serve as the fixed pin 41, respectively.

  FIGS. 15 and 16 are a partial cross-sectional top view and a partial side cross-sectional view of the load lock portion in the abnormally mounted state of the wafer in the holder according to the present embodiment and the substrate transfer system using the holder.

  As shown in the figure, even when the wafer 2S is mounted outside the specified area Q in the load lock chamber 24, the wafer 2S rides on one of the tilt detection pins 51 to tilt the wafer. Since the optical axis path of the sensor 47 (47a, 47b) is shielded from light by the wafer 2S, the sample transport apparatus 10 can reliably detect the abnormal mounting state of the wafer 2S.

Thus, according to the holder 50 according to the present embodiment and the substrate transfer system using the holder 50, the above-described,
1) The inclination detection pin 51 is within the diameter circle of the small diameter wafer 2S contacting the inner wall of the load lock chamber 24, and is separated from the inner wall of the load lock chamber 24 by a radius of the small diameter wafer 2S or more. The non-regulated region portion Q (shaded portion in FIG. 10) is disposed so as to avoid the optical axis path of the wafer tilt sensor 47 (47a, 47b).
2) Another inclination detection pin 51 adjacent to the one inclination detection pin 51 around the outer periphery of the defined region portion P is a diameter circle of the small-diameter wafer 2S in contact with the one inclination detection pin 51. The optical axis path of the wafer tilt sensor 47 (47a, 47b) is erected and arranged so as not to shield itself in the non-regulated region portion Q in the inside,
3) The tilt detection pin 51 is defined when a part of the non-regulated area portion Q is in contact with or overlaps with the defined area portion P on which the small-diameter wafer 2S on the mounting surface 28 in the load lock chamber 24 is mounted. It is arranged so as to circumscribe the region portion P, and serves also as a fixed pin 41 (41a, 41b) or a movable pin 42 for positioning and fixing the wafer 2S with respect to the specified region portion P.
On the basis of the preconditions, the first to third arrangement examples described above can be appropriately combined to create a holder 50 for observation inspection of a sample smaller than the sample of the observation specification size, and the observation specification for normal transport Even if a sample (wafer 2S) smaller than the sample of the size (wafer 2L) is transported, abnormal loading of the sample (wafer 2S) can be reliably detected.

1 length measurement SEM, 2 wafer, 2L observation specification size wafer,
2S small-diameter wafer, 10 sample transfer device, 11 load port,
12 Sample transfer robot, 13 Wafer storage case,
14 Mini-environment type sample transport mechanism, 20 Scanning electron microscope body,
21 Load lock section, 22 Stage section, 23 Lens barrel section,
24 load lock chamber, 25 sample chamber, 26 holder, 27 wheel,
28 mounting surface, 29 sample stage, 30 holder, 31 housing,
32 base part, 33 rail, 34 load door, 35 gate valve,
36, 37 mounting base, 41 fixed pin, 42 movable pin, 43 support pin,
46 Wafer presence sensor, 47 Wafer tilt sensor, 50 holder,
51 Tilt detection pin

Claims (3)

A substrate holder for the target substrate having a substrate having a size smaller than that of a normal observation specification size substrate as a target substrate on the mounting surface and having the same external dimensions as those for mounting a normal observation specification size substrate. Because
One half the size of the target substrate from the inner wall of the chamber arranged for mounting the substrate, other than the prescribed area on the mounting surface, where the target substrate normally mounted on the mounting surface faces. An inclination detection pin on which the target board rides is placed upright in a non-regulated area on the placement surface that is separated from the above, and the target board is abnormally mounted on a normal observation specification size board provided in the chamber. A substrate holder, wherein the sensor is in a posture that can be detected by a sensor that detects the substrate. The substrate holder according to claim 1,
A plurality of the inclination detection pins are erected and arranged around the outer periphery of the prescribed region portion,
Another inclination detection pin adjacent to one inclination detection pin around the outer periphery of the prescribed area portion is within the size range of the target substrate in contact with the one inclination detection pin. A substrate holder, wherein the substrate holder is arranged upright in an outer region portion. The substrate holder according to claim 1,
In a load lock chamber equipped with a sensor that detects abnormal loading of a wafer, it is used as a holder to load a target wafer of a size smaller than a normal observation specification size wafer,
A substrate transport system for a length-measuring SEM, wherein the target wafer is transported together with the holder from the load lock chamber to a vacuum sample chamber irradiated with charged particle beams.

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