Vacuum processing apparatus and vacuum processing method

Abstract

Provided are a vacuum processing apparatus and a vacuum processing method that can suppress deterioration of the degree of vacuum in a vacuum chamber as the destination when transferring a specimen between two vacuum chambers. Accordingly, a control device (30) controls the transfer of a wafer (600) from an LC (102) to an SC (101) via an LC-SC gate valve (510). At this time, on the basis of controlling the LC-SC gate valve (510) to a closed state, the control device (30) stops vacuum evacuation based on a TMP (401A) for a first period of time, measures the internal pressure of the LC (102) using a pressure gauge (103) in a state where the vacuum evacuation has been stopped, and controls the LC-SC gate valve (510) to an open state when the measured internal pressure reaches a first reference value.

Description

Technical Field

[0001] The present invention relates to a vacuum processing apparatus and a vacuum processing method, and more particularly to an apparatus for processing a semiconductor wafer that releases gas. Background Art

[0002] In a device production line, in order to measure the size of fine patterns formed on a semiconductor wafer (hereinafter referred to as a wafer) and inspect defects on the device, a device using a scanning electron microscope is used. For example, a CD-SEM (Critical Dimension-Scanning Electron Microscope) is used for measuring the dimensions of gates and contact holes in semiconductor devices, and a defect inspection SEM or the like is used for defect inspection.

[0003] Patent Document 1 discloses a charged particle beam apparatus that can appropriately maintain the throughput of the apparatus for each specimen having a different gas release amount. When the specimen is transferred from the exchange chamber to the specimen chamber, this charged particle beam apparatus switches the determination value for completing the vacuum evacuation in the exchange chamber between a specimen with a large gas release amount and a specimen with a small gas release amount.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013-182792 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] Taking a CD-SEM, which is one of the vacuum processing apparatuses, as an example, the outline of the vacuum processing apparatus will be described. The CD-SEM is configured to connect a load lock chamber (hereinafter referred to as LC) and a main chamber (hereinafter referred to as SC). The load lock chamber takes a wafer to be inspected into the apparatus from outside the apparatus, and the main chamber irradiates the wafer with an electron beam for inspection. An electron optical system is provided in the SC and irradiates the wafer in the SC with an electron beam.

[0009] In the normal use state of the apparatus, the pressure in the SC needs to be maintained in a high vacuum state in order to perform measurement based on electron beam irradiation. On the other hand, the pressure in the LC serves as an airlock when transferring the wafer between outside the apparatus and the SC. Therefore, every time a wafer is taken in or a wafer that has completed inspection is taken out, the pressure rapidly changes from atmospheric pressure to high vacuum. Therefore, the LC and the SC each have a turbomolecular pump (TMP (turbomolecular pump)).

[0010] In addition, in addition to the exhaust based on the TMP, the LC also has a roughing pump (dry pump, etc.) for evacuating in the range from the atmosphere to a low vacuum, and a venting device for restoring the inside of the LC to atmospheric pressure using nitrogen (N2) or the like. Regarding the chamber volumes of the LC and the SC, the volume of the LC is small and that of the SC is large. This is because, from the necessity of pressure variation, it is preferable that the volume of the LC be small.

[0011] Next, the wafer transfer in the CD-SEM and the accompanying vacuum exhaust process will be described. In the CD-SEM, with the inside of the LC at atmospheric pressure, the gate valve that controls the opening and closing of the opening between the LC and the outside of the device is opened, and the wafer is taken into the LC, and then this gate valve is closed. Next, in the state where the wafer is in the LC, the LC is evacuated with a dry pump, and then evacuated with the TMP until a high vacuum is achieved.

[0012] Moreover, when the internal pressure of the LC reaches a predetermined value, the CD-SEM opens the gate valve between the LC and the SC, and transfers the wafer to the SC that has been in a high vacuum state in advance. The wafer is irradiated with an electron beam in the SC, and thus inspection is performed. After that, the wafer is taken out of the device. The process at this time is roughly the reverse process of the process at the time of loading described above. That is, after the CD-SEM transfers the wafer from the SC to the LC, with the wafer present in the LC, the inside of the LC is made atmospheric pressure by the venting device. After that, the CD-SEM opens the gate valve that controls the opening and closing of the opening between the LC and the outside of the device, and takes out the wafer to the outside of the device.

[0013] In recent years, due to the influence of manufacturing processes and the like, the number of wafers that release gas has increased. They are called external gas wafers. Especially in wafers for memories such as DRAMs, there is a tendency for the amount of gas released to increase. Therefore, a CD-SEM that can also handle the next-generation external gas wafers with an increasing tendency of gas release amount is required.

[0014] Therefore, it is considered to use the charged particle beam device of Patent Document 1. In the process of Patent Document 1, during the process of the CD-SEM described above, the degree of vacuum inside the LC that determines the transfer timing from the LC to the SC is switched between a normal wafer and an external gas wafer. Specifically, in the case of an external gas wafer, the degree of vacuum inside the LC is set to a high vacuum (low pressure) compared to a normal wafer.

[0015] If the method of Patent Document 1 is used, when the gas release from the external gas wafer is exhausted in the LC, the gas release after being transferred to the SC can be suppressed. However, in the method of Patent Document 1, even when the gas release from the external gas wafer continues in the LC, the internal pressure of the LC sometimes reaches the high vacuum (low pressure) set for the external gas wafer due to the vacuum exhaust capacity of the TMP. In this case, the external gas wafer continues to release gas even after being transferred to the SC. As a result, the vacuum degree of the SC deteriorates, and the performance of the device may decrease.

[0016] Therefore, one of the objects of the present disclosure is to provide a vacuum processing apparatus and a vacuum processing method capable of suppressing deterioration of the vacuum degree in the vacuum chamber of the transfer destination when transferring a specimen between two vacuum chambers.

[0017] According to the description and the drawings of the present specification, the above and other objects and new features of the present disclosure will become clear.

[0018] Means for Solving the Problem

[0019] The vacuum processing apparatus of the present disclosure includes: a first vacuum chamber; a second vacuum chamber connected to the first vacuum chamber via a valve; a vacuum pump for vacuum-exhausting the first vacuum chamber; a pressure gauge for measuring the internal pressure of the first vacuum chamber; and a computer system. The computer system controls the transfer of the specimen from the first vacuum chamber to the second vacuum chamber via the valve. At this time, the computer system, while controlling the valve to the closed state, stops the vacuum exhaust based on the vacuum pump for a first period of time, measures the internal pressure of the first vacuum chamber using the pressure gauge in the state where the vacuum exhaust is stopped, and when the measured internal pressure reaches a first reference value, controls the valve to the open state.

[0020] Advantageous Effects of the Invention

[0021] According to the present disclosure, when transferring a specimen between two vacuum chambers, deterioration of the vacuum degree in the vacuum chamber of the transfer destination can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram showing a structural example of the vacuum processing apparatus according to Embodiment 1.

[0023] Figure 2 It shows in Figure 1 The flowchart which is an example of the control process which the control apparatus which is a comparative example performs in the vacuum processing apparatus.

[0024] Figure 3 It is used for Figure 2 The supplementary figure which demonstrates the detail of the control process.

[0025] Figure 4is a supplementary figure for explaining the details of the control process for Figure 2 The following is a supplementary figure for explaining the details of the control process for

[0026] Figure 5 is a supplementary figure for explaining the details of the control process for Figure 2 The following is a supplementary figure for explaining the details of the control process for

[0027] Figure 6 is a supplementary figure for explaining the details of the control process for Figure 2 The following is a supplementary figure for explaining the details of the control process for

[0028] Figure 7 is a supplementary figure for explaining the details of the control process for Figure 2 The following is a supplementary figure for explaining the details of the control process for

[0029] Figure 8 represents a flowchart of an example of a control process different from Figure 1 executed by the control device as a comparative example in the vacuum processing apparatus of Figure 2 The following is a flowchart of an example of a control process different from

[0030] Figure 9 represents a flowchart of an example of a control process executed by the control device of Embodiment 1 in the vacuum processing apparatus of Figure 1 The following is a flowchart of an example of a control process executed by the control device of Embodiment 1 in the vacuum processing apparatus of

[0031] Figure 10 represents a diagram of an example of the vacuum degree migration of LC after stopping the vacuum exhaust based on TMP in the vacuum processing apparatus of Figure 1 The following is a diagram of an example of the vacuum degree migration of LC after stopping the vacuum exhaust based on TMP in the vacuum processing apparatus of

[0032] Figure 11A represents a flowchart of an example of a control process executed by the control device of Embodiment 2 in the vacuum processing apparatus of Figure 1 The following is a flowchart of an example of a control process executed by the control device of Embodiment 2 in the vacuum processing apparatus of

[0033] Figure 11B is a flowchart following Figure 11A The following is a flowchart following

[0034] Figure 11C is a flowchart following Figure 11B The following is a flowchart following DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, embodiments will be described with reference to the accompanying drawings. In the drawings, elements having the same function are sometimes denoted by the same reference numerals or corresponding reference numerals. In addition, the drawings show embodiments that follow the principles of the present disclosure, but these are for understanding the present disclosure and are not intended to limitatively interpret the present disclosure. The description in this specification is merely a typical example and does not limit the scope or application examples of the technical solutions of the present disclosure in any sense.

[0036] In an embodiment, those skilled in the art have described it in sufficient detail for implementing the present disclosure. However, it should be understood that other installations / forms are also possible, and structural / constructural changes and replacement of various elements can be made without departing from the scope and spirit of the technical idea of the present disclosure. Therefore, the following description should not be construed as being limited thereto.

[0037] (Embodiment 1)

[0038] "Structure of Vacuum Processing Apparatus"

[0039] Figure 1 It is a schematic diagram showing a structural example of the vacuum processing apparatus of Embodiment 1. In the specification, the case where the vacuum processing apparatus is a charged particle beam apparatus as one of semiconductor inspection apparatuses is taken as an example, and in particular, the case of being a CD-SEM is taken as an example. However, the vacuum processing apparatus is not limited to semiconductor inspection apparatuses, and for example, it can also be a semiconductor manufacturing apparatus such as a plasma CVD (Chemical Vapor Deposition) apparatus or a sputtering apparatus. In addition, semiconductor inspection apparatuses can also be, for example, bright-field microscopes, spectroscopic analysis apparatuses, optical measurement apparatuses, optical inspection apparatuses, etc.

[0040] Figure 1 The shown vacuum processing apparatus 10 has an apparatus main body 20 and a control apparatus 30. First, the apparatus main body 20 will be described. The apparatus main body 20 has an LC102 which is a vacuum chamber and an SC101. The SC101 is connected to the LC102 via an LC-SC gate valve 510. The LC102 serves as a pre-chamber when taking in and out a wafer (i.e., a specimen) 600 to be inspected from outside the apparatus. The SC101 serves as an inspection chamber for inspecting the wafer 600. In addition, the dotted line 105 in the SC101 is a cutout provided for convenience of showing the inside of the SC101.

[0041] The SC101 has: a holding mechanism 201 which holds the wafer 600 by electrostatic force or the like; a multi-axis stage 200 which has a function of driving the holding mechanism 201 in a plurality of directions within the SC101; and an electron optical system (charged particle optical system) 300 which emits a charged particle beam (representatively an electron beam). When inspecting the wafer 600 within the SC101, the multi-axis stage 200 positions the wafer 600 held by the holding mechanism 201 relative to the electron optical system 300. And in the state where this positioning has been performed, the electron optical system 300 irradiates the wafer 600 with an electron beam.

[0042] Thus, in order to perform inspection using an electron beam, the internal pressure of the SC101 needs to be maintained at a high vacuum state. On the other hand, the LC102 functions as a fore chamber when transporting the wafer 600 from outside the apparatus to the SC101. Therefore, every time the wafer 600 is taken in or the inspected wafer 600 is taken out, the internal pressure of the LC102 varies within the range from atmospheric pressure to high vacuum. Thus, the LC102 and the SC101 each have vacuum pumps, namely the TMP401A and 401B, for making the inside in a high vacuum state.

[0043] In addition, in addition to the evacuation by the TMP401A, the LC102 has dry pumps, namely the dry pumps 400A, which are vacuum pumps responsible for vacuum evacuation in the range from atmospheric pressure to low vacuum, and a venting device 104 that ejects nitrogen (N2) or the like for returning the inside of the LC to atmospheric pressure. In addition, the dry pump 400B functions as an auxiliary pump for the TMP401A and 401B. The pipe 402B is arranged to connect between the dry pump 400B and the TMP401B and between the dry pump 400B and the TMP401A.

[0044] The pipe 402A connects between the dry pump 400A and the LC102 via a pipe valve 530. The pressure gauge 103 measures the internal pressure of the LC102. In addition, in the specification, as one of the ways to obtain the vacuum degree of the LC102, the internal pressure of the LC102 is measured, but as long as the vacuum degree of the LC102 can be obtained, other ways can also be used. The inter-device gate valve 500 is provided at the opening between the LC102 and the outside of the apparatus. The LC-SC inter-gate valve 510 is provided at the opening between the LC102 and the SC101. The TMP valve 520 is a vacuum valve provided at the opening between the LC102 and the TMP401A.

[0045] Here, the LC102 minimizes the volume in order to make the pressure change rapidly. Therefore, if the two vacuum chambers, namely the LC102 and the SC101, are compared, the volume of the LC102 is very small compared to the SC101. In this way, by reducing the volume of the LC102 to make the pressure change rapidly, the production cycle time of wafer inspection can be shortened.

[0046] Next, the control device 30 will be described. The control device 30 is realized, for example, by a computer system having a processor and a memory. Specifically, the control device 30 can be, for example, a wiring board (in other words, a control board) equipped with various components including a processor and a memory, etc. The control device 30 controls the device main body 20 by the processor executing a control program stored in the memory. As one of such controls, the control device 30 controls the transfer of the wafer 600 from the LC102 to the SC101 via the LC-SC inter-gate valve 510.

[0047] 《Operation of vacuum processing device (comparative example)》

[0048] Here, in order to easily understand the present disclosure, Figures 2 - 7 , the general control process of transporting a normal wafer from outside the device to the SC101 and the accompanying vacuum exhaust will be described in sequence. Figure 2 It means in Figure 1 A flowchart of an example of a control process executed by a control device as a comparative example in a vacuum processing apparatus of . Figures 3 - 7 It is used for Figure 2 The details of the control process are illustrated in the supplementary figures.

[0049] Figure 3 express Figure 1 The processing sequence of step S100 represents the preparation stage before the wafer 600 is taken in from the outside. First, in the front stage of step S100, the valve cores 540 of the four valves facing LC102, i.e., the device internal and external gate valve 500, the LC-SC gate valve 510, the TMP valve 520, and the piping valve 530 are all controlled to the closed state CL.

[0050] In the state where LC102 is sealed in this way, the control device of the comparative example controls the ventilation device 104 to make the inside of LC102 at atmospheric pressure using nitrogen (N2) (step S100). In addition, the internal pressure of LC102 is measured by the pressure gauge 103. In addition, the two pipes 402A and 402B are connected to Figure 1 The dry pumps 400A, 400B are shown connected.

[0051] Figure 4 express Figure 1 The processing sequence of steps S101 and S102 shows the state where the wafer 600 is loaded into the LC 102. Figure 3 Then, the control device of the comparative example uses an unillustrated device internal and external transfer device to transfer the wafer 600 from the device internal and external gate valve 500 in the open state OP and places it in the unillustrated wafer holding portion in LC102 (step S102).

[0052] Figure 5 express Figure 1 The processing sequence of steps S103 and S104 represents the sequence of evacuating LC102 from the atmospheric state. TMP401A cannot perform vacuum evacuation from the atmospheric state. Therefore, before starting the evacuation of TMP401A from the atmospheric state to the low vacuum state, it is necessary to perform the evacuation of LC102 from the atmospheric state to the low vacuum state. Figure 1 The dry pump 400A is used for vacuum exhaust. Figure 5As shown, the control device of the comparative example then Figure 4 In the state of, the gate valve 500 between the inside and outside of the device in the open state OP is controlled to the closed state CL (step S103). After that, the control device of the comparative example performs vacuum exhaust of LC102 by controlling the piping valve 530 in the closed state CL to the open state OP (step S104).

[0053] Figure 6 Indicates Figure 1 The processing sequence of steps S105 to S107 of represents the sequence of evacuating LC102 from low vacuum to high vacuum. If it continues Figure 5 In the state of, the internal pressure of LC102 reaches the first LC internal vacuum degree (reference value) RV1 which is the TMP exhaust start pressure. When the control device of the comparative example detects that this first LC internal vacuum degree RV1 is reached using the pressure gauge 103 (step S105), it controls the piping valve 530 in the open state OP to the closed state CL (step S106). Then, the control device of the comparative example controls the TMP valve 520 in the closed state CL to the open state OP (step S107). Thereby, vacuum exhaust of LC102 based on TMP401A is started.

[0054] Figure 7 Indicates Figure 1 The processing sequence of steps S108 to S110 of represents the sequence of transferring the wafer 600 from LC102 to SC101. After Figure 6 In the state of, the internal pressure of LC102 reaches the second LC internal vacuum degree (reference value) RV2 which is lower than the first LC internal vacuum degree (reference value) RV1 (i.e., higher vacuum).

[0055] When the control device of the comparative example detects that the second LC internal vacuum degree RV2 is reached using the pressure gauge 103 (step S108), it controls the LC-SC intermediate gate valve 510 in the closed state CL to the open state OP (step S109). After that, the control device of the comparative example uses an LC-SC intermediate transfer device (not shown) to transfer the wafer 600 to SC101 via the LC-SC intermediate gate valve 510 in the open state OP (step S110). At this time, SC101 is previously in a high vacuum state. In addition, after the transfer of the wafer 600, the control device of the comparative example controls the LC-SC intermediate gate valve 510 in the open state OP to the closed state CL.

[0056] The control process as above can be applied to the case of an ordinary wafer 600 as an object. However, there are various types of wafers. For example, due to the influence of manufacturing processes, etc., sometimes the wafers themselves release gas. These wafers are called external gas wafers. In the case of external gas wafers, as in the case of Patent Document 1, for example, consider usingFigure 8 The control process as shown below.

[0057] Figure 8 It represents in Figure 1 In the vacuum processing apparatus, it is a flowchart showing an example of a control process different from that executed by the control apparatus as a comparative example and related to Figure 2 In Figure 8 compared with Figure 2 step S102 is replaced by step S202, and step S108 is replaced by step S208. In step S202, instead of a normal wafer, an external gas wafer (specimen) is carried into LC102. In step S208, the second LC internal vacuum degree (reference value) RV2a reaching a high vacuum is detected.

[0058] In this way, Figure 8 is characterized in that the detection of the second LC internal vacuum degree for determining the transfer timing from LC102 to SC101 is performed at a second LC internal vacuum degree RV2a that is higher vacuum (lower pressure) than the second LC internal vacuum degree RV2 of Figure 2 . This is a method of exhausting gas while the external gas wafer is in LC102, thereby suppressing gas release after transfer to SC101. In addition, the second LC internal vacuum degrees RV2 and RV2a are values within the pressure range based on the vacuum exhaust capacity of TMP.

[0059] Here, Figure 2 the detection in step S108 of Figure 8 and the detection in step S208 of Figure 2 are both performed in the state where the TMP valve 520 is controlled to the open state OP in step S107. Therefore, the detection of the LC internal vacuum degree is performed in parallel with the vacuum exhaust based on TMP401A. In addition, for the convenience of subsequent description, the common steps S100 and S101 in Figure 2 and Figure 8 are called common process A (step S1000), and the steps S103 to S107 are called common process B (step S1001).

[0060] "Operation of the Vacuum Processing Apparatus (Embodiment 1)"

[0061] On the other hand, in recent years, the situation where it is difficult to exhaust gas for external gas wafers has been increasing. When through Figure 8When the method shown is used to process such next-generation external gas wafers, the vacuum level is confirmed in parallel with the vacuum exhaust based on TMP401A. Therefore, in step S208, the second LC internal vacuum level RV2a of high vacuum is sometimes reached in a state where gas release and vacuum exhaust are balanced. In this case, since the gas is not exhausted, the next-generation external gas wafer continues to release gas even after being transferred to SC101, and the vacuum level of SC101, which should maintain high vacuum, deteriorates.

[0062] The deterioration of the vacuum level of SC101, for example, causes a defect called contamination in the next-generation external gas wafer to be inspected, where organic substances are sintered by an electron beam, and in some cases, it may lead to a situation where electron beam irradiation cannot be performed. In addition, since the volume of SC101 is much larger than that of LC102, if the vacuum level deteriorates, it takes a long time to recover. Therefore, it is beneficial to use the method of Embodiment 1 shown below.

[0063] Figure 9 It represents an example of the control process executed by the control device of Embodiment 1 in the Figure 1 vacuum processing apparatus. In Figure 9 , the control device 30 of Embodiment 1 first executes the common process A in step S1000, and then transfers the next-generation external gas wafer (specimen) into LC102 (step S302). Next, the control device 30 executes the common process B in step S1001.

[0064] Next, when the control device 30 detects the second LC internal vacuum level RV2a of high vacuum using the pressure gauge 103, that is, when the internal pressure of LC102 is equal to or lower than the second LC internal vacuum level RV2a (step S208), it controls the TMP valve 520 in the open state OP to the closed state CL (step S303). Thereby, the control device 30 stops the vacuum exhaust of LC102 based on TMP401A. In the state where this vacuum exhaust has been stopped, the control device 30 waits for the waiting time TA (step S304).

[0065] After that, the control device 30 measures the internal pressure of LC102 using the pressure gauge 103 and determines whether the measured internal pressure has reached the third LC internal vacuum level (reference value) RV3, that is, whether it is equal to or lower than the third LC internal vacuum level RV3 (step S305). Here, when the measured internal pressure reaches the third LC internal vacuum level RV3, the control device 30 regards the gas as exhausted and transfers to step S109. Then, in step S109, the control device 30 controls the LC-SC gate valve 510 in the closed state CL to the open state OP, and in step S310, transfers the next-generation external gas wafer to SC101 via the LC-SC gate valve 510.

[0066] On the other hand, in step S305, when the measured internal pressure has not reached the third LC internal vacuum degree RV3, that is, when it is higher than the third LC internal vacuum degree RV3, it is regarded that the gas has not been exhausted, and the TMP valve 520 in the closed state CL is controlled to the open state OP to start vacuum exhaust again (step S306). After that, after this vacuum exhaust for the waiting time TB (step S307), the control device 30 returns to step S303.

[0067] As described above, on the basis of controlling the LC-SC inter-valve 510 to the closed state CL, the control device 30 stops the vacuum exhaust based on TMP401A for the time until the second LC internal vacuum degree RV2a is reached in step S303. In this stopped state, the internal pressure of LC102 is measured in step S305. Then, when the measured internal pressure reaches the third LC internal vacuum degree RV3, the control device 30 controls the LC-SC inter-valve 510 in the closed state CL to the open state OP (step S109).

[0068] On the other hand, when the internal pressure measured in step S305 has not reached the third LC internal vacuum degree RV3, the control device 30 stops after the vacuum exhaust based on TMP401A for the waiting time TB (steps S307, S303). Then, the control device 30 similarly repeats the cyclic process of measuring the internal pressure of LC102 in the state where the vacuum exhaust is stopped (steps S303 to S307) until the measured internal pressure reaches the third LC internal vacuum degree RV3.

[0069] Here, the user can set the waiting time TA in step S304 and the waiting time TB in step S307 to arbitrary values. And the user can set the third LC internal vacuum degree RV3 to an arbitrary value. However, these values need to be determined appropriately so that the determination in step S305 can be accurately performed. Regarding this point, the following will be described.

[0070] Figure 10 It shows an example of the vacuum degree migration of the LC after stopping the vacuum exhaust based on TMP in the Figure 1 vacuum processing device. In the case of gas exhaustion of the next-generation external gas wafer, as shown by the curve G100 in the case of exhaustion, the internal pressure of LC102 slowly deteriorates from the second LC internal vacuum degree RV2a. On the other hand, in the case of non-exhaustion of the gas, as shown by the curve G101 in the case of non-exhaustion, the internal pressure of LC102 deteriorates rapidly from the second LC internal vacuum degree RV2a. Thus, by stopping the vacuum exhaust based on TMP401A, a clear difference in the characteristics of vacuum degree migration occurs depending on the presence or absence of gas exhaustion.

[0071] Figure 9 The waiting time TA in step S304 of is determined, for example, as the time required for the actual opening and closing operation of the TMP valve 520. As a specific example, the waiting time TA is set to several seconds, for example. In Figure 10 represents such a waiting time TA. At the time point when the waiting time TA has elapsed, a clear pressure difference occurs between the curve G100 in the depleted case and the curve G101 in the non-depleted case. Therefore, for example, as Figure 10 shown, by setting the third LC internal vacuum degree RV3 in Figure 9 step S305 of to a value higher than a specified amount based on the second LC internal vacuum degree RV2a, the determination in Figure 9 step S305 of can be accurately performed.

[0072] In addition, as Figure 9 the waiting time TB for the re-vacuum exhaust time in step S307 of is appropriately determined according to the type of the next-generation external gas wafer, etc. Usually, the waiting time TB is a time sufficiently longer than the waiting time TA. For example, it can be several tens of seconds or more. In this way, by appropriately setting the waiting time TA, TB, and the third LC internal vacuum degree RV3, it is possible to accurately determine whether there is gas depletion for various types of next-generation external gas wafers. In addition, the third LC internal vacuum degree RV3 is preferably set for each device in consideration of the device difference, and is preferably updated regularly in consideration of the change over time.

[0073] 《Various Modification Examples》

[0074] In Figure 9 steps S303 to S307 of, the control device 30 repeatedly performs the opening and closing operation of the TMP valve 520. However, the control device 30 may repeatedly perform the adjustment of the opening degree instead of the opening and closing operation of the TMP valve 520. In addition, in steps S303 to S307, the control device 30 performs a loop process until the vacuum degree of LC102 reaches the third LC internal vacuum degree RV3. In other words, the control device 30 determines whether it is possible to transfer to step S109 based on the comparison result between the vacuum degree of LC102 and a predetermined threshold value. However, the control device 30 may also determine whether it is possible to transfer to step S109 based on the change amount or response characteristics of the vacuum degree of LC102 during the loop process.

[0075] That is, regarding Figure 9During the process up to the transfer to step S109, the open state of the TMP valve 520 is not maintained, and it is only necessary to repeatedly perform the opening and closing operation of the TMP valve 520 or adjust the opening degree. Thus, the control device 30 can determine whether it is possible to transfer to step S109 based on the degree of vacuum of LC102 when the TMP valve 520 is in the closed state or when the opening degree is adjusted to a small value.

[0076] 《Main effects of Embodiment 1》

[0077] As described above, by using the method of Embodiment 1, when transferring a sample between two vacuum chambers, it is possible to suppress the deterioration of the degree of vacuum in the vacuum chamber at the transfer destination. As a result, the performance of the device can be improved. Specifically, for example, it is possible to suppress the generation of contamination in the vacuum chamber at the transfer destination and to inspect the sample with high precision in SC101. In addition, in a vacuum chamber with a large capacity at the transfer destination, there is no need to wait for the degree of vacuum to recover, and the throughput of the device can be increased.

[0078] (Embodiment 2)

[0079] 《Operation of the vacuum processing device (Embodiment 2)》

[0080] In Embodiment 1, when the waiting time TB in Figure 9 step S307 is excessively shortened, the opening and closing of the TMP valve 520 are repeated many times before the gas is exhausted. In this case, the number of operations of the TMP valve 520 increases, and thus the period until the end of life may be shortened. Also, each time the gas exhaustion determination is made, the vacuum exhaust of LC102 based on TMP401A stops, so the time required until the gas is exhausted increases, and as a result, the throughput of the device may decrease. On the other hand, when the waiting time TB is made too long, the time for the next vacuum exhaust becomes excessive, and in this case, the throughput of the device may also decrease. Therefore, it is beneficial to use the following method.

[0081] Figure 11A is a flowchart showing an example of the control process executed by the control device of Embodiment 2 in a Figure 1 vacuum processing device. Figure 11B is the flowchart immediately following Figure 11A the flowchart, Figure 11C is the flowchart immediately following Figure 11B the flowchart. For example, most external gas wafers manufactured by the same manufacturing process have similar characteristics, and the vacuum exhaust time required for gas exhaustion also mostly has the same tendency (required time). The method of Embodiment 2 is as follows: measure the vacuum exhaust time required for gas exhaustion for a certain type of wafer, and when processing wafers of the same type, for example, in Figure 9An awaiting period reflecting the measured vacuum exhaust time is inserted between step S208 and step S303.

[0082] First, an explanation is given of Figure 11A , Figure 11B and Figure 11C . The control device 30 targets the next-generation external gas wafer (specimen) for which a cycle process of vacuum exhaust has been performed, and while measuring the internal pressure in Figure 11B step S305, it measures the total time of vacuum exhaust required for the internal pressure to reach the third LC internal vacuum degree (reference value) RV3 with reference to Figure 11B step S412. And when the control device 30 targets a wafer of the same type as the measured next-generation external gas wafer ( Figure 11B step S411), by inserting an awaiting period in Figure 11B step S416, it causes the measured total time to be reflected in the first vacuum exhaust time before the cycle process is generated.

[0083] In addition, as one of the conditions for determining whether the wafers are of the same type in step S411, the control device 30 measures the required arrival time T2 in Figure 11A step S401. The required arrival time T2 is, for example, the time required for the internal pressure of LC102 to reach the second LC internal vacuum degree (reference value) RV2a from a predetermined start time point. Representatively, the predetermined start time point is Figure 8 the time point when the TMP valve 520 is opened in step S107, but it is not limited to this, and it can also be the time point of any step before step S107. The control device 30 determines, in Figure 11B step S411, that wafers with the same required arrival time T2 are wafers of the same type.

[0084] And when the control device 30 targets the wafer via the awaiting period in Figure 11B step S416, it also determines in Figure 11B step S305 whether the internal pressure measured in the state where the vacuum exhaust has been stopped has reached the third LC internal vacuum degree RV3. And when the internal pressure measured in this wafer reaches the third LC internal vacuum degree RV3 and this wafer is set as the previous wafer, the control device 30 determines, in the previous wafer and the current wafer to be processed immediately afterwards, Figure 11A step S401 whether the required arrival time T2 is the same. When the required arrival time T2 is the same, the control device 30 determines, in Figure 11A step S411, that the current wafer is of the same type as the previous wafer.

[0085] Next, an explanation is given of Figure 11A ,Figure 11B and Figure 11C will be described in detail. In Figure 11A , similar to the case of Figure 9 , through step S1000, step S302, and step S1001, the internal pressure of LC102 reaches the second LC internal vacuum degree RV2a (step S208). At this time, the control device 30 measures the required arrival time T2 required from a predetermined start time point until the second LC internal vacuum degree RV2a is reached (step S401). Generally speaking, the more gas is released from the next-generation external gas wafer, the longer the required arrival time T2. If the wafers are of the same type, the required arrival time T2 is also the same.

[0086] In the next step S402, the control device 30 determines whether the required arrival time T2 is the same between the last wafer and the current wafer. When the required arrival time T2 is the same, the control device 30 updates the consecutive occurrence count SNt2 of the same T2 (step S403). For example, the consecutive occurrence count SNt2 is n when the required arrival time T2 is the same in consecutive n wafers.

[0087] On the other hand, when the required arrival time T2 is not the same in step S402, the control device 30 performs full initialization (step S404). Specifically, the control device 30 resets the consecutive occurrence count SNt2 in step S403, the consecutive occurrence count SNlp in step S425 described later to 0, and changes the setting of the waiting time TC in step S414 described later to none. In addition, the control device 30 sets the flags FLC and FLL described later to 0. Figure 11C of Figure 11B to 0, and changes the setting of the waiting time TC in step S414 described later to none. In addition, the control device 30 sets the flags FLC and FLL described later to 0.

[0088] In Figure 11A after step S403 or step S404, as Figure 11B shown, the control device 30 sets the flags FLC and FLL for discriminating the paths in the process to 0 (step S410). Then, the control device 30 determines whether the current wafer is of the same type as the last wafer (step S411). The determination condition will be described later. When the current wafer is not of the same type as the last wafer, the control device 30, similar to the case of Figure 9 , controls the TMP valve 520 to the closed state CL (step S303a), waits through the waiting time TA (step S304a), and determines whether the third LC internal vacuum degree RV3 is reached (step S305).

[0089] When the third LC internal vacuum degree RV3 is not reached in step S305, the control device 30, similar to the case of Figure 9In the same manner as described above, by controlling the TMP valve 520 to the open state OP (step S306), the vacuum exhaust of LC102 is performed again for the waiting time TB (step S307). After that, the control device 30 returns to step S303a through the processes of steps S412 and S413, and, in the same manner as Figure 9 described above, after repeatedly performing the loop process until the third LC internal vacuum degree RV3 is reached, the process proceeds to Figure 11C step S420.

[0090] During this loop process, the control device 30 updates the loop count Nlp in step S412 (step S412). When the waiting in step S307 is executed m times along with the loop process, the loop count Nlp is m. In addition, the control device 30 changes the flag FLL to 1 in step S413 (step S413). The flag FLL indicates that the loop process has been executed.

[0091] On the other hand, when the current wafer and the previous wafer are of the same type in step S411, the control device 30 determines whether there is a setting for the waiting time TC (step S414). When there is a setting for the waiting time TC, the control device 30 directly extends the current vacuum exhaust by the amount of the waiting time TC (step S416). When there is no setting for the waiting time TC in step S414, the control device 30 sets the waiting time TC, for example, by multiplying the waiting time TB in step S307 by the loop count Nlp obtained in step S412 (step S415), and proceeds to step S416. The loop count Nlp at this time represents the number of times executed for the previous wafer.

[0092] After that, the control device 30, in the same manner as Figure 9 described above, controls the TMP valve 520 to the closed state CL (step S303b), waits through the waiting time TA (step S304b), and determines whether the third LC internal vacuum degree RV3 has been reached (step S305). In addition, when extending the current vacuum exhaust in step S416, the control device changes the flag FLC indicating this to 1 (step S417).

[0093] Next, in Figure 11C steps S420, S421, and S422, the control device 30 determines the states of the flags FLC and FLL. First, when FLC = 0 & FLL = 1, that is, when performing the intermittent process of the vacuum exhaust along with the loop process without extending the current vacuum exhaust, the control device 30 stores the finally updated loop count Nlp in Figure 11B step S412 (step S423).

[0094] Furthermore, the control device 30 determines whether the number of cycles Nlp stored for the current wafer is consistent with the number of cycles Nlp stored for the previous wafer (step S424). If the number of cycles Nlp is consistent in step S424, the number of consecutive occurrences SNlp of the same Nlp is updated (step S425). For example, if the number of cycles Nlp is consistent in n consecutive wafers, the number of consecutive occurrences SNlp is n. On the other hand, if the number of cycles Nlp is inconsistent in step S424, the control device 30 updates the number of consecutive occurrences SNlp (step S425). Figure 11A As in step S404, full initialization is performed (step S426).

[0095] That is, in the example of this flowchart, for example, in the first to j-th (j is an integer greater than or equal to 2) wafers, Figure 11A The time required for arrival T2 in step S401 is the same as Figure 11B If the number of cycles Nlp in is the same, the j wafers are considered to be of the same type, and the j+1 wafer is also likely to be of the same type. And, in the case where the arrival time T2 of the j+1 wafer is the same as that of the j wafers, the j+1 wafer is determined to be of the same type, and the selection Figure 11B The path of step S416 in .

[0096] Therefore, the control device 30 Figure 11B In step S411, for example, when the number of consecutive occurrences SNt2 of the same T2 is j+1 (j is an integer greater than 2) and the number of consecutive occurrences SNlp of the same Nlp is j, the current wafer is determined to be of the same type as the previous wafer. At this time, the minimum value of j, that is, when the number of consecutive occurrences is greater than or equal to several times, the possibility of determining the next wafer as the same type is high, is arbitrarily determined by the user.

[0097] In addition, when the continuous same state is interrupted after reaching the required time T2, Figure 11A In step S404, full initialization is performed. Similarly, when the state of continuous consistency of the number of cycles Nlp is interrupted, after Figure 11C In step S424, full initialization is performed in step S426. If full initialization is performed in any of them, the state of the first wafer is returned to.

[0098] Return to Figure 11CIn steps S420, S421, and S422, when FLC = 1 & FLL = 1, that is, when the current vacuum exhaust is extended but the intermittent processing of the vacuum exhaust with the cycle process is performed, the control device 30 performs full initialization in step S426. On the other hand, when FLC = 1 & FLL = 0, that is, when the current vacuum exhaust is extended and the intermittent processing of the vacuum exhaust with the cycle process is not performed, the control device 30 considers that the condition of step S424 is satisfied, and updates the continuous occurrence count SNlp of the same Nlp in step S425. Thus, even when the current vacuum exhaust is extended, the control device 30 can make a correct determination based on the continuous occurrence counts SNt2 and SNlp in Figure 11B step S411.

[0099] After the processing of step S425 or step S426, the control device 30 controls the LC-SC gate valve 510 to the open state OP (step S109) in the same way as Figure 9 the case. Then, the control device 30 transports the next-generation external gas wafer to SC101 via the LC-SC gate valve 510 (step S310).

[0100] In addition, in Figure 11A step S402, the range in which the required arrival time T2 is regarded as equivalent can be arbitrarily set by the user. Also, in the same way as Figure 9 the case, Figure 11B the waiting time TB in step S307 can also be arbitrarily set by the user. By such user settings, a flow chart reflecting the user's intention can be constructed. For example, in a case where some excess vacuum exhaust time may occur, but the path of step S416 is preferably selected as much as possible, the user only needs to set the range regarded as equivalent to the required arrival time T2 to be wide to a certain extent and set the waiting time TB to be long.

[0101] In addition, here, in Figure 11C step S424, the agreement / disagreement of the cycle count Nlp is determined. However, depending on the situation, an error tolerance range of, for example, around ±1 can also be set in this determination condition. This is because, depending on the length of the waiting time TB and also depending on at which time point within the waiting time TB the gas runs out, even for the same type of wafer, an error may occur in the cycle count Nlp. Also, for the same reason, an error tolerance range of around ±1 can also be set for Figure 11B the determination condition in step S411, that is, the continuous occurrence count SNlp of the same Nlp.

[0102] 《Various Modification Examples》

[0103] Although the drawings are omitted, for example, it is also possible to set a branch for additionally determining the presence or absence of gas exhaustion based on the change in the degree of vacuum in SC101 after Figure 11C step S310. And in this branch, when it is determined that the gas release continues, full initialization may be performed in the same manner as in steps S404 and S426.

[0104] In addition, for example, when the gas release continues extremely long, some abnormality may occur in the device. Therefore, the control device 30 may also determine the upper limit of the number of repetitions of the above-described cyclic process according to the user's setting. Specifically, for example, after Figure 11B step S412, it is only necessary to add a branch for determining whether the number of cycles Nlp has reached the upper limit value determined by the user. In this branch, when the number of cycles Nlp reaches the upper limit value, the control device 30 may also notify the user of this meaning or forcibly end the device operation. At this time, the control device 30 may also forcibly end the device operation according to a command from the user.

[0105] And in Figure 11A , Figure 11B and Figure 11C , assuming that the type of the wafer is unknown, it is determined in Figure 11B step S411 whether the current wafer is of the same type as the previous wafer. However, for example, when the control device 30 has previously determined the type of the wafer by pre-inputting a wafer identifier or the like, it may also select the path on the side of Figure 11B step S416 without determining the equality of the required time T2 or the like. The waiting time TC at this time is determined based on the total time of vacuum exhaust measured for the same type of wafer in the past.

[0106] 《Main effects of Embodiment 2》

[0107] As described above, by using the method of Embodiment 2, in addition to obtaining the same effects as those described in Embodiment 1, it is also possible to reduce the number of opening and closing operations of the TMP valve 520. As a result, for example, it is possible to extend the device life, improve the device throughput, and the like.

[0108] (Embodiment 3)

[0109] 《Operation of the vacuum processing device (Embodiment 3)》

[0110] The control device 30 may also distinguish and use according to the type of the wafer (specimen) Figure 2 , Figure 8 , Figure 9 (or Figure 11A , Figure 11B and Figure 11C) control process. That is, the control device 30 can also switch whether to measure the internal pressure of LC102 in a state where vacuum exhaust is stopped or in a state where vacuum exhaust is performed, according to the type of wafer.

[0111] Specifically, the control device 30, for example, is the same as in Figure 11A steps S208 and S401, and measures the time (referred to as T3) from a predetermined start time point until the second LC internal vacuum degree RV2 used in Figure 2 step S108 is reached. And the control device 30 compares the time T3 with predetermined comparison times Tc1 and Tc2 (Tc1 < Tc2).

[0112] When the comparison result is T3 ≤ Tc1, the control device 30 executes the processing after Figure 2 step S109. When the comparison result is Tc1 < T3 ≤ Tc2, the control device 30 waits until the second LC internal vacuum degree RV2a of high vacuum in Figure 8 step S208 is reached, and then executes the processing after Figure 8 step S109. When the comparison result is Tc2 < T3, the control device 30 waits until the second LC internal vacuum degree RV2a of high vacuum in Figure 9 step S208 is reached, and then executes the processing after Figure 9 step S303.

[0113] In addition, in the case of using such a method, the control device 30 can, for example, be fixed to any one of the above-mentioned 3 control processes according to the user's request, or can be automatically switched within any two of the 3. Also, as described in Embodiment 2, when the type of wafer is determined in advance, the control device 30 can also automatically select any one of the 3 control processes according to the type of the wafer without measuring the time T3.

[0114] 《Main effects of Embodiment 3》

[0115] As described above, by using the method of Embodiment 3, in addition to obtaining the same effects as those described in Embodiment 1, it is also possible to achieve, for example, an increase in device throughput, an extension of device life, etc. Specifically, in the case of an ordinary wafer as the object, there is no need to wait until the second LC internal vacuum degree RV2a of high vacuum is reached. In addition, in the case of an external gas wafer where gas is easily exhausted rather than an external gas wafer where gas is difficult to exhaust, the number of opening and closing times of the TMP valve 520 can be reduced.

[0116] Explanation of reference numerals

[0117] 10: Vacuum processing device, 20: Device main body, 30: Control device, 101: SC (vacuum chamber), 102: LC (vacuum chamber), 103: Pressure gauge, 300: Electron optical system, 401A, 401B: TMP, 510: Gate valve between LC and SC, 520: TMP valve, 600: Wafer, CL: Closed state, Nlp: Number of cycles, OP: Open state, RV1: Vacuum degree in the first LC (reference value), RV2, RV2a: Vacuum degree in the second LC (reference value), RV3: Vacuum degree in the third LC (reference value), TA, TB, TC: Waiting time.

Claims

1. A vacuum processing device, characterized in that the vacuum processing device has: a first vacuum chamber having a first gate valve that opens and closes when carrying a sample in and out of the device; a second vacuum chamber connected to the first vacuum chamber via a second gate valve; a vacuum pump that evacuates the first vacuum chamber; a pressure gauge that measures the internal pressure of the first vacuum chamber; and a computer system that controls the transfer of the sample from the first vacuum chamber to the second vacuum chamber via the second gate valve, the computer system, based on controlling the second gate valve to a closed state, stops the vacuum evacuation by the vacuum pump for a first time, and in the state where the vacuum evacuation is stopped, measures the internal pressure of the first vacuum chamber, and when the measured internal pressure reaches a first reference value, controls the second gate valve to an open state, when the measured internal pressure does not reach the first reference value, the computer system repeatedly performs a cyclic process until the measured internal pressure reaches the first reference value, and the cyclic process is to stop after performing the vacuum evacuation by the vacuum pump for a second time and measure the internal pressure of the first vacuum chamber in the state where the vacuum evacuation is stopped.

2. The vacuum processing device according to claim 1, characterized in that the first vacuum chamber is a load lock chamber.

3. The vacuum processing device according to claim 2, characterized in that the computer system measures the total time of the vacuum evacuation required until the measured internal pressure reaches the first reference value for the first sample for which the cyclic process has occurred, and when the sample is of the same type as the first sample, reflects the total time in the first time.

4. The vacuum processing device according to claim 3, characterized in that the computer system measures a third time required from a predetermined start time point until the internal pressure of the first vacuum chamber reaches a second reference value higher than the first reference value, and determines whether the sample is of the same type as the first sample based on the third time.

5. The vacuum processing device according to claim 4, characterized in that the computer system, for a second sample, stops after performing the vacuum evacuation by the vacuum pump for the first time that reflects the total time, and determines whether the measured internal pressure reaches the first reference value in the state where the vacuum evacuation is stopped, when the measured internal pressure in the second sample reaches the first reference value and the third time in the second sample and the third sample processed immediately after the second sample is the same, the computer system determines that the third sample is of the same type as the second sample.

6. The vacuum processing device according to claim 2, characterized in that the computer system determines an upper limit of the number of repetitions of the cyclic process according to the user's setting.

7. The vacuum processing device according to claim 1, characterized in that The vacuum pump is a TMP, i.e., a turbo molecular pump.

8. The vacuum processing apparatus according to claim 1, wherein the computer system can switch whether to measure the internal pressure of the first vacuum chamber in a state where the vacuum exhaust is stopped or in a state where the vacuum exhaust is being performed, according to the type of the specimen.

9. The vacuum processing apparatus according to claim 1, wherein the vacuum processing apparatus is a charged particle beam apparatus that irradiates a charged particle beam to the specimen transferred to the second vacuum chamber.

10. The vacuum processing apparatus according to claim 1, wherein the computer system controls the transfer of the specimen from the first vacuum chamber to the second vacuum chamber in such a manner that it is based on the change amount or response characteristic of the measured internal pressure in the cyclic process.

11. A vacuum processing method for a vacuum processing apparatus, the vacuum processing apparatus having: a first vacuum chamber having a first gate valve that opens and closes in accordance with the transfer of the specimen in and out of the apparatus; a second vacuum chamber connected to the first vacuum chamber via a second gate valve; a vacuum pump that evacuates the first vacuum chamber; and a pressure gauge that measures the internal pressure of the first vacuum chamber, characterized in that when controlling the transfer of the specimen from the first vacuum chamber to the second vacuum chamber via the second gate valve, on the basis of controlling the valve to a closed state, the vacuum exhaust based on the vacuum pump is stopped for a first time, and in the state where the vacuum exhaust is stopped, the internal pressure of the first vacuum chamber is measured using the pressure gauge, and when the measured internal pressure reaches a first reference value, the second gate valve is controlled to an open state, when the measured internal pressure does not reach the first reference value, a cyclic process is repeated until the measured internal pressure reaches the first reference value, and the cyclic process is stopped after the vacuum exhaust based on the vacuum pump is performed for a second time, and the internal pressure of the first vacuum chamber is measured in the state where the vacuum exhaust is stopped.

12. The vacuum processing method according to claim 11, wherein the first vacuum chamber is a load lock chamber.

13. The vacuum processing method according to claim 12, wherein for the first specimen for which the cyclic process has occurred, the total time of the vacuum exhaust required until the measured internal pressure reaches the first reference value is measured, and when the specimen of the same type as the first specimen is used as the object, the total time is reflected in the first time.

14. The vacuum processing method according to claim 13, wherein the third time required from a predetermined start time point until the internal pressure of the first vacuum chamber reaches a second reference value higher than the first reference value is measured, and whether the specimen is of the same type as the first specimen is determined based on the third time.

15. The vacuum processing method according to claim 14, wherein Stop after performing the vacuum evacuation based on the vacuum pump for the first time corresponding to the total time with respect to the second specimen, and determine whether the measured internal pressure has reached the first reference value in the state where the vacuum evacuation has been stopped. When the measured internal pressure in the second specimen reaches the first reference value and the third time is the same in the second specimen and the third specimen processed immediately after the second specimen, determine that the third specimen is of the same type as the second specimen.

16. The vacuum treatment method according to claim 11, wherein: Transfer the specimen from the first vacuum chamber to the second vacuum chamber according to the change amount or response characteristic of the measured internal pressure in the cyclic treatment.

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