Semiconductor processing device

Abstract

The purpose of the present disclosure is to provide a semiconductor processing device that makes it possible to achieve both increased speed of sample exchange and reduced vibration of a wafer conveyance robot. A semiconductor processing device according the present disclosure performs a first operation for unloading a sample from a stage and a second operation for loading a sample onto the stage, wherein at least a part of the first operation and at least a part of the second operation are performed in parallel, and the second operation is completed before the first operation is completed (see fig. 5B).

Description

Semiconductor processing apparatus

[0001] The present disclosure relates to a semiconductor processing apparatus.

[0002] In a semiconductor processing apparatus such as a charged particle beam apparatus, a wafer transfer robot is used to transfer a sample such as a semiconductor wafer into the apparatus or to carry out a processed wafer out of the apparatus. For example, a vacuum transfer robot is used to transfer a wafer from a load lock chamber (hereinafter referred to as an LC) for connecting to an atmospheric pressure environment outside the apparatus to a sample stage in a sample chamber (hereinafter referred to as an SC) in a vacuum environment.

[0003] In a semiconductor processing apparatus such as a charged particle beam apparatus, after the processing of a certain wafer is completed, the processed wafer on the sample stage and the unprocessed wafer to be processed next are exchanged using a vacuum transfer robot, and then the next wafer is processed, so that a plurality of wafers can be processed continuously.

[0004] Since the wafer cannot be processed while the wafer is being exchanged, the sample exchange time is directly related to the wafer processing capacity (hereinafter referred to as throughput) per unit time of the apparatus. Therefore, shortening of the sample exchange time is required. Also, high repetitive transfer accuracy onto the sample stage is required at the same time. However, in order to ensure the repetitive transfer accuracy, the wafer cannot be placed on the sample stage while the wafer transfer robot is residually vibrating after stopping. Therefore, it is required to achieve both high-speed sample exchange and low vibration of the wafer transfer robot.

[0005] According to the technique disclosed in Patent Document 1, by making the path for loading the substrate onto the substrate stage and the path for unloading the substrate different from each other, it is possible to perform the loading and unloading of the substrate in parallel and shorten the cycle time when exchanging the substrate.

[0006] Japanese Patent Application Laid-Open No. 2017-108169

[0007] The technology disclosed in Patent Document 1 involves mounting a substrate on a substrate holder and transporting the substrate holder. However, when transporting samples smaller than large substrates, such as a silicon wafer with a diameter of 300 mm, it is undesirable to use a holder to improve throughput. Therefore, wafers are transported by mounting them on a material that prevents the sample from slipping, such as a viscoelastic material. However, for example, when exchanging a processed wafer with an unprocessed wafer on a sample stage, especially in a vacuum environment, there are limitations on the wafer holding means of the wafer transport robot, and when transporting at an acceleration or speed above a certain level, the wafer may slip.

[0008] On the other hand, when transporting wafers individually without mounting them on a holder or similar device, in order to ensure the accuracy of repeated transport onto the sample stage, the wafer cannot be placed on the sample stage until the residual vibrations after the wafer transport robot has moved onto the stage have settled down. Therefore, it is difficult to achieve both high speed and low vibration simultaneously.

[0009] This disclosure has been made in view of the above-mentioned issues, and aims to provide a semiconductor processing apparatus that can achieve both high-speed sample exchange and low vibration of wafer transport robots.

[0010] The semiconductor processing apparatus according to this disclosure performs a first operation to unload a sample from a stage and a second operation to load a sample onto a stage, wherein at least a portion of the first operation and at least a portion of the second operation are performed in parallel with each other, and the second operation is completed before the first operation is completed.

[0011] The semiconductor processing apparatus described herein makes it possible to achieve both high-speed sample exchange and low vibration of the wafer transport robot. Other issues, configurations, and advantages of this disclosure will become clear from the following description of the embodiments.

[0012] This is a configuration diagram of a semiconductor processing apparatus according to Embodiment 1. It shows the state in which the vacuum transfer robot 31 is in its home position. It shows the state in which only the unload hand 318 is extended toward the sample stage. It shows the state in which only the load hand 313 is extended toward the sample stage. It shows the state in which both the load hand 313 and the unload hand 318 are extended toward the stage. This is a flowchart showing an example of the flow of the sample exchange method in this disclosure. It shows a side view of the wafer W1 mounted on the sample stage 11 and the lift mechanism 12. It shows a side view of the wafer W1 mounted on the sample stage 11 and the lift mechanism 12. It shows the state of the sample stage 11 and the vacuum transfer robot 31 in step 200. It shows the state of the sample stage 11 and the vacuum transfer robot 31 after the operation of step 202 is completed. It shows the state after both the transfer of wafer W2 by the load hand 313 in step 203 and the retrieval of wafer W1 by the unload hand 318 in step 205 have been completed. This shows wafer W2 being placed on the sample stage 11, wafer W1 being recovered, and the vacuum transfer robot 31 returning to its home position. This shows an example of a time chart when processing multiple wafers continuously in the semiconductor measurement apparatus according to Embodiment 1.

[0013] <Embodiment 1> Figure 1 is a configuration diagram of a semiconductor processing apparatus according to Embodiment 1 of the present disclosure. The semiconductor processing apparatus in Figure 1 is configured as a charged particle beam apparatus that irradiates a sample (semiconductor wafer in the following example) with a charged particle beam. The semiconductor measuring apparatus comprises SC1, two LCs (LC2A, LC2B), a vacuum transfer robot 31, a robot chamber 3 (hereinafter referred to as RC), and a mini-enclosure 4. The vacuum transfer robot 31 transfers the wafer between the sample stage 11 and LC2A and LC2B. RC3 is a chamber that houses the vacuum transfer robot 31.

[0014] The inside of SC1 is in a vacuum state in order to irradiate the wafer W1 to be processed with a charged particle beam. Inside SC1 are an electron gun 13 for irradiating the wafer with a charged particle beam and an optical microscope 14 for low-magnification observation and alignment.

[0015] RC3 is kept under vacuum, similar to SC1. LC2A and LC2B are pre-exhaust chambers connecting the vacuum environment of RC3 to the atmospheric environment of MiniEnvironment 4. When connecting to the inside of RC3, the environment becomes vacuum, and when connecting to MiniEnvironment 4, the environment becomes atmospheric. When RC3 is connected to LC2A or LC2B, the vacuum level may decrease slightly, and valve 21 is provided to prevent this decrease in vacuum from spreading into SC1. Furthermore, valves 22A, 22B, 23A, and 23B are provided to isolate LC2A from RC3, LC2B from RC3, LC2A from MiniEnvironment 4, and LC2B from MiniEnvironment 4. These valves are closed when changing the pressure inside LC2A and LC2B, and opened when transporting wafers.

[0016] LC2A and LC2B are equipped with pre-aligners 24A and 24B, respectively, for measuring the eccentricity of the wafer placed inside the LC.

[0017] The mini-environment 4 is equipped with a transport robot 41 for transporting the wafer W2 stored in the hoop (FOUP) (Front-Opening Unified Pod) 5 to LC2A or LC2B.

[0018] The sample stage 11 is equipped with an electrostatic chuck (not shown) to secure the wafer placed on the sample stage 11 so that it does not slip. When the sample stage 11 operates with the wafer on it, a voltage is applied to the electrostatic chuck, and the wafer is secured by electrostatic force.

[0019] Next, the structure and operation of the vacuum transfer robot 31 will be described using Figures 2A, 2B, 2C, and 2D.

[0020] Figure 2A shows the vacuum transfer robot 31 in its home position. The vacuum transfer robot 31 includes a lifting mechanism (not shown) for raising and lowering the entire vacuum transfer robot 31, a rotation mechanism (not shown) for rotating the entire vacuum transfer robot 31, and a load hand 313 (second arm) and an unload hand 318 (first arm) for transporting wafers. The load hand 313 consists of a lower link 311 and an upper link 312, and power from a motor (not shown) is transmitted from a joint 314, and the load hand 313 moves in the Y-axis direction by a steel belt (not shown) passed through the lower link 311 and upper link 312. The unload hand 318 is similarly composed of a lower link 316 and an upper link 317, and power from a motor (not shown) is transmitted from a joint 319, and the unload hand 318 moves in the Y-axis direction by a steel belt (not shown) passed through the lower link 316 and upper link 317.

[0021] The load hand 313 and unload hand 318 are fitted with viscoelastic bodies 315, indicated by black circles, which can hold wafers placed on the hands using static friction. It is preferable to use a non-adhesive viscoelastic body, such as silicone rubber, as the viscoelastic body. By using a non-adhesive viscoelastic body, no extra force is required to pull the wafer away from the hand when placing it, thus reducing the risk of the wafer bouncing.

[0022] When the load hand 313 and unload hand 318 are in their home positions, they are in the same position in the X and Y directions, with only their height in the Z direction differing. The same is true when the arms are extended toward the stage. Figures 2A to 2D illustrate the state where the load hand 313 is on the upper side, but a structure in which the load hand 313 is on the lower side may also be used.

[0023] Figure 2B shows the state where only the unloading hand 318 is extended toward the sample stage. Figure 2C shows the state where only the loading hand 313 is extended toward the sample stage. Figure 2D shows the state where both the loading hand 313 and the unloading hand 318 are extended toward the stage.

[0024] Next, a sample exchange method using the vacuum transfer robot 31 in this disclosure will be explained with reference to Figures 3 to 6.

[0025] Figure 3 is a flowchart showing an example of the sample exchange method in this disclosure. Figures 5A to 5D show the movements of wafers W1 and W2, and the vacuum transfer robot 31 when exchanging samples on the sample stage 11 using the vacuum transfer robot 31. For simplicity, LC2A and LC2B are not shown. The operations of each part will be explained in order below.

[0026] Step 200: After the predetermined processing on the wafer W1 is completed, the sample stage 11 is moved to a predetermined position for sample exchange. Details of this step will be explained again in Figure 5A.

[0027] Step 201: The wafer W1 is lifted up by the sample stage 11 (lift mechanism 12: described later). Details of this step will be explained again in Figures 4A to 4B.

[0028] Step 202: After confirming with a sensor or the like that the lift mechanism 12 has lifted the wafer W1 to a predetermined height in step 201, the unload hand 318 is extended between the sample stage 11 and the wafer W1. At this time, since the unload hand 318 is not holding the wafer, it is not a problem if it operates with an acceleration that would cause the wafer to slip if it were holding it. Therefore, in step 202, the unload hand 318 is operated with the largest possible acceleration or speed.

[0029] Step 203: After confirming with a sensor or the like that the lift mechanism 12 has lifted the wafer W1 to a predetermined height in step 201, the unload hand 318 starts moving, and at the same time, the load hand 313 also starts moving toward the stage. At this time, since the wafer W2 is mounted on the load hand 313, it is required to operate with an acceleration or speed that prevents the wafer W2 from slipping. On the other hand, the load hand 313 can place the wafer W2 on the sample stage 11 only after the unload hand 318 has retrieved the wafer W1 from the sample stage 11 and the unload hand 318 has moved toward its home position. Therefore, it is sufficient to extend the load hand 313 onto the sample stage 11 before the retrieval operation is completed. Thus, in step 203, the load hand 313 operates with a slow acceleration or speed that minimizes residual vibration of the wafer W2 when it stops. At this time, based on the operating acceleration in step 202 and the acceleration or velocity of the unload hand 318 in step 205, which will be explained later, the time it takes for the unload hand 318 to complete the retrieval of the wafer W1 is calculated in advance, and the load hand 313 is made to transport the wafer W2 onto the sample stage 11 within that time, so that throughput is not reduced even when operated at a slow acceleration or velocity.

[0030] Step 204: The entire vacuum transfer robot 31 is moved upward to retrieve the wafer W1 onto the unload hand 318. Details of this step will be explained again in Figure 5B.

[0031] Step 205: Once it is confirmed in step 204 that the wafer W1 is mounted on the unload hand 318, the unload hand 318 is moved to the home position. At this time, since the wafer W1 is on the unload hand 318, if it is moved with the largest possible acceleration or speed as in step 202, the wafer will slip on the unload hand 318, leading to wafer damage. Therefore, in step 205, the wafer is transported with the largest possible acceleration or speed while ensuring a safety factor, within the range of acceleration or speed that prevents the wafer from slipping.

[0032] Step 206: The entire vacuum transfer robot 31 is lowered to place the wafer W2 on the load hand 313 onto the lift mechanism 12. Details of this step will be explained again in Figure 5C.

[0033] Step 207: After confirming that the wafer W2 is mounted on the lift mechanism 12, the load hand 313 is moved to the home position. At this time, since there is no wafer on the load hand 313, it is acceptable to operate it with an acceleration that would cause the wafer to slip if it were being held, as in step 202. Therefore, in step 207, the load hand 313 is operated with the largest possible acceleration or speed.

[0034] Step 208: The wafer W2 is placed on the sample stage 11 by lowering the lift mechanism 12. Details of this step will be explained again in Figure 5D.

[0035] Step 209: After the wafer W2 is placed on the sample stage 11, a voltage is applied to the electrostatic chuck before the sample stage 11 moves to fix the wafer W2 in place by electrostatic force and prevent it from sliding on the sample stage 11.

[0036] Figures 4A and 4B show a side view of the wafer W1 mounted on the sample stage 11 and the lift mechanism 12. The lift mechanism 12 is equipped with three pins 121 for lifting the wafer and can be moved up and down using a ball screw (not shown) or the like. The pins 121 are arranged concentrically with the wafer to stably hold it. Figure 4A shows the lift mechanism 12 in its normal position, and Figure 4B shows the wafer W1 being lifted by the lift mechanism 12. To prevent the wafer W1 from slipping on the lift mechanism 12 when it is lifted, a viscoelastic material (not shown) is provided at the contact points between the pins 121 and the wafer W1, allowing the wafer W1 to be held by static friction. This viscoelastic material is a non-adhesive viscoelastic material, similar to the viscoelastic material 315 provided in the load hand 313 and unload hand 318. This reduces the risk of the wafer bouncing, as no extra force is required to pull the wafer away from the hand when placing it down. In step 200, after the sample stage 11 moves to a predetermined position for sample exchange, the lift mechanism 12 provided on the sample stage 11 operates to lift the wafer W1 on the sample stage 11, resulting in the state shown in Figure 4B. In step 201, the vacuum transport robot 31 does not operate.

[0037] Figure 5A shows the sample stage 11 and the vacuum transfer robot 31 in step 200. After the predetermined processing of wafer W1 in the semiconductor processing apparatus is completed, the sample stage 11 moves to a predetermined position for sample exchange, and at the same time, the valve 21 is opened to allow the wafer to pass between SC1 and RC3. At this time, the vacuum transfer robot 31 can maximize throughput by holding the next wafer to be processed, W2, on the load hand 313 from LC2A or LC2B while processing wafer W1 is being performed.

[0038] Figure 5B shows the state of the sample stage 11 and the vacuum transfer robot 31 after the operation of step 202 is completed. After it is confirmed that the unload hand 318 has moved to a predetermined position below the wafer W1, the lifting mechanism of the vacuum transfer robot 31 is operated, and the entire vacuum transfer robot 31 is moved upward by a predetermined stroke. This operation places the wafer W1 on the unload hand 318. At this time, the operation of the load hand 313 in step 203 may continue, or the operation of the load hand 313 may be interrupted only during the lifting operation.

[0039] Figure 5C shows the state after both the transfer of wafer W2 by the load hand 313 in step 203 and the retrieval of wafer W1 by the unload hand 318 in step 205 have been completed. After confirming that this state has been reached, the lifting mechanism of the vacuum transfer robot 31 is operated to lower the entire vacuum transfer robot 31 and place the wafer W2 on the load hand 313 onto the lift mechanism 12.

[0040] Figure 5D shows the wafer W2 being placed on the sample stage 11, the wafer W1 being retrieved, and the vacuum transfer robot 31 returning to its home position. After confirming that this state has been reached, the lift mechanism 12 is lowered to place the wafer W2 onto the sample stage 11.

[0041] Next, the overall operation flow of the charged particle beam apparatus to maximize the throughput of the apparatus using the sample exchange method described in this disclosure will be explained. In order to maximize throughput using the sample exchange method described in this disclosure, it is necessary that the wafer W2 to be placed on the sample stage 11 is already prepared on the vacuum transfer robot 31 when the processing of wafer W1 is completed. Furthermore, it is also necessary to transport the wafer that was processed before wafer W1 to the FOUP outside the apparatus. Therefore, while wafer W1 is being processed in the sample chamber 1, it is necessary to transport the wafer that was processed before wafer W1 and to transport the wafer from FOUP 5 to RC3. At this time, in order to transport the wafer from the atmospheric pressure environment of FOUP 5 and mini-environment 4 to the vacuum environment of RC3, LC2A or LC2B needs to be connected to mini-environment 4 in an atmospheric pressure environment to transport the wafer, and then the internal pressure needs to be reduced by vacuum evacuation. Since the process of reducing this pressure takes time, if the transfer of the next wafer to be processed is started from FOUP 5 after the processing of wafer W1 has begun, wafer W2 may not be ready on the vacuum transfer robot 31 by the time the processing of wafer W1 is finished, resulting in waiting time and a potential decrease in throughput. Therefore, the charged particle beam apparatus shown in Figure 1 is equipped with two LCs, allowing the operation of transferring wafers from sample chamber 1 to FOUP 5 and the operation of transferring wafers from FOUP 5 to sample chamber 1 to be performed in parallel. This makes it possible to maintain throughput.

[0042] <Embodiment 1: Summary> In the semiconductor measuring apparatus according to Embodiment 1, the unload hand 318 (first arm) unloads the sample from the stage (first operation), and the load hand 313 (second arm) loads the sample onto the stage (second operation). At least a portion of the first operation and at least a portion of the second operation are performed in parallel with each other, and the load hand 313 completes the second operation before the first operation is completed. This makes it possible to achieve both high-speed sample exchange and low vibration of the wafer transfer robot.

[0043] In the semiconductor measurement device according to Embodiment 1, the load hand 313 is arranged to move above the unload hand 318. This is for the following reasons. When unloading the sample from the stage, the sample is in a lifted state, and in this state, the load hand 313 advances toward the stage. This is because unloading and loading are performed in parallel. At this time, if the load hand 313 is arranged below the unload hand 318, the load hand 313 will collide with the lift mechanism in the lifted state. On the other hand, if the load hand 313 is above the unload hand 318, the load hand 313 will advance further above the lift-up mechanism, so it will not collide with the lift mechanism.

[0044] In the semiconductor measurement device according to Embodiment 1, the vacuum transfer robot 31 (transfer mechanism) has two degrees of freedom by the movement of the hand in the Y-axis direction, and further has two degrees of freedom by lifting or rotating the entire vacuum transfer robot 31, having a total of four degrees of freedom. In other words, each hand can only move along the same axial direction as each other (along the Y-axis direction in the drawing), and for example, while the load hand 313 is transporting the sample along the Y-axis direction, the unload hand 318 cannot perform an operation such as carrying out the sample along the X-axis direction. Such a four-degree-of-freedom structure is useful for simplifying the structure of the vacuum transfer robot 31, but the operations that can be performed in parallel by both hands are limited. It should be added that the present disclosure has the significance that it can achieve both high-speed sample exchange and low vibration of the wafer transfer robot under such constraints.

[0045] <Embodiment 2> Fig. 6 shows an example of a time chart when processing a plurality of wafers continuously in the semiconductor measurement device according to Embodiment 1. The horizontal axis represents time, and in order from the top, it represents the processing performed in Mini En, LC2A, LC2B, RC, SC, or the time of wafer exchange. The arrows indicate that the wafers are being transported. For example, the leftmost upper arrow indicates that the wafer is being transported between Mini En and LC2A. Using Fig. 6, an example of the flow of wafer transfer when processing a plurality of wafers continuously in the semiconductor measurement device will be described.

[0046] 601 represents the time for transferring a wafer between the mini-environment 4 and LC2A or between the mini-environment 4 and LC2B using the transfer robot 41 in the mini-environment 4. 602 represents the time for evacuating the inside of LC2A or LC2B from an atmospheric pressure environment to a vacuum environment. 603 represents the time for transferring a wafer between LC2A and RC3 or between LC2B and RC3 using the vacuum transfer robot 31. 604 represents the time for exchanging the wafer on the sample stage 11 using the vacuum transfer robot 31 as described in Embodiment 1. 605 represents the time for processing the wafer by the semiconductor measuring device. 606 represents the time for performing a gas supply process to return the inside of LC2A or LC2B from a vacuum environment to an atmospheric pressure environment. 607 represents the time for taking out a wafer from the FOUP 5 or returning the wafer to the FOUP 5.

[0047] The operations will be described in order from the far left in FIG. 6. First, starting from the state where the transfer robot 41 (the third arm) in the mini-environment 4 holds the wafer A (not shown) to be processed next, the wafer A is transferred into LC2A.

[0048] Next, an evacuation process is performed inside LC2A. After the pressure inside LC2A has sufficiently decreased, the wafer A inside LC2A is placed on the load hand 313 of the vacuum transfer robot 31. Then, the wafer A is mounted on the sample stage 11 and processed. In parallel with these operations, in the mini-environment 4, the wafer B (not shown) for which processing is to be performed next after the wafer A is taken out from the FOUP, and then transferred into LC2B. The evacuation of LC2B is performed in parallel with the processing of the wafer A inside SC1. When the pressure inside LC2B has sufficiently decreased, the wafer B is mounted on the vacuum transfer robot 31 inside RC3. In parallel with the evacuation of LC2B, in LC2A, in order to carry in the wafer C for which processing is to be performed next after the wafer B, the pressure inside LC2A is returned to atmospheric pressure. When the processing of the wafer A inside SC1 is completed, the wafer A and the wafer B are exchanged using the above-described method.

[0049] Once processing is complete, wafer A is transported into LC2B using a vacuum transport robot 31, returning the inside of LC2B to an atmospheric pressure environment, and then transported to FOUP5 via minien 4 by transport robot 41. In parallel, wafer C is transported by transport robot 41 into LC2A, which has returned to an atmospheric pressure environment via minien 4, and vacuum evacuation is performed inside LC2A to prepare wafer C for transport into RC3.

[0050] Subsequently, by continuously repeating the loading and unloading of wafers in the same manner, it becomes possible to perform processing continuously without waiting for wafer transport. The time chart described in this embodiment is merely one example, and various embodiments are conceivable.

[0051] <Embodiment 3> In the above embodiments, some of steps 201 and 202 may be performed in parallel. For example, step 202 may be started while the stage is being lifted in step 201, and the unload hand 318 may be moved toward the stage. If the stage has not been lifted up when the unload hand 318 arrives at the stage, the unload hand 318 will remain stationary and wait until the lifting is complete. This allows the unload hand 318 to be moved toward the stage quickly.

[0052] <Regarding Variations of the Disclosure> This disclosure is not limited to the embodiments described above, and includes various variations. For example, the embodiments described above are described in detail for the purpose of explaining this disclosure clearly, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0053] In the embodiments described above, an example was given in which the semiconductor processing apparatus is configured as a charged particle beam apparatus. However, it should be noted that this disclosure is also applicable to other semiconductor processing apparatuses in which a transport mechanism transfers a semiconductor sample between the sample stage and the transport mechanism.

[0054] 1 Sample Chamber 11 Sample Stage 13 Electron Gun 14 Optical Microscope 2A Pre-exhaust Chamber 2B Pre-exhaust Chamber 24A Pre-aligner 24B Pre-aligner 3 Robot Chamber 31 Vacuum Transfer Robot 4 Mini-en 41 Transfer Robot 5 FOUP W1 Wafer W2 Wafer

Claims

1. A semiconductor processing apparatus for processing a semiconductor sample, comprising: a first arm and a second arm for transporting the sample; and a sample stage on which the sample is placed, wherein the first arm performs a first operation by moving from a first initial position to the sample stage, placing a first sample placed on the sample stage onto the first arm, and then moving from the sample stage back to the first initial position to retrieve the first sample; the second arm performs a second operation by moving from a second initial position with the second sample placed on the second arm to the sample stage to transport the second sample to the sample stage, wherein at least a portion of the first operation and at least a portion of the second operation are performed in parallel with each other, and the second arm completes the second operation before the first operation is completed.

2. The semiconductor processing apparatus according to claim 1, characterized in that the first arm moves with a first acceleration or a first velocity while a sample is mounted on the first arm, and moves with an acceleration greater than the first acceleration or a velocity greater than the first velocity when no sample is mounted on the first arm, and the second arm moves with a second acceleration or a second velocity while a sample is mounted on the second arm, and moves with an acceleration greater than the second acceleration or a velocity greater than the second velocity when no sample is mounted on the second arm.

3. The semiconductor processing apparatus according to claim 2, characterized in that the first acceleration or first velocity is an acceleration or velocity such that the sample mounted on the first arm does not slip on the first arm, and the second acceleration or second velocity is an acceleration or velocity such that the sample mounted on the second arm does not slip on the second arm.

4. The semiconductor processing apparatus according to claim 2, characterized in that the second arm moves from the second initial position to the sample stage with an acceleration smaller than the first acceleration or a speed smaller than the first velocity when performing the second operation.

5. The semiconductor processing apparatus according to claim 1, characterized in that the second arm starts the second operation at the same time as the first arm starts the first operation, or within a predetermined time range before or after the start of the first operation, thereby completing the second operation before the first operation is completed.

6. The semiconductor processing apparatus according to claim 1, characterized in that the second arm transports the second sample to the sample stage by the second operation, places the second sample on the sample stage, and then moves from the sample stage to the second initial position with an acceleration or velocity greater than the acceleration or velocity when moving from the second initial position to the sample stage.

7. The semiconductor processing apparatus according to claim 1, characterized in that the first arm and the second arm each comprise a hand for placing a sample and a viscoelastic body for holding the sample on the hand.

8. The semiconductor processing apparatus according to claim 1, wherein the sample stage is equipped with a lift mechanism capable of lifting a sample placed on the sample stage, the first arm receives the first sample lifted by the lift mechanism from the sample stage, the second arm places the second sample mounted on the second arm onto the lift mechanism, and the lift mechanism lowers the second sample received from the second arm onto the sample stage, thereby placing it on the sample stage.

9. The semiconductor processing apparatus according to claim 1, characterized in that the first initial position and the second initial position are in the same position on the horizontal plane, but their vertical heights are different from each other.

10. The semiconductor processing apparatus according to claim 9, characterized in that the first initial position is vertically lower than the second initial position.

11. The semiconductor processing apparatus according to claim 1, further comprising a transport mechanism that drives the first arm and the second arm with one degree of freedom, wherein the transport mechanism is capable of performing the following actions: moving the entire transport mechanism up and down, and rotating the entire transport mechanism horizontally, thereby having four degrees of freedom.

12. The semiconductor processing apparatus further comprises a sample chamber for housing the sample stage, a first pre-exhaust chamber and a second pre-exhaust chamber capable of changing the internal pressure from vacuum to atmospheric pressure when a sample is transferred between the sample chamber and the atmospheric environment, wherein the first sample is transported onto the sample stage via the first pre-exhaust chamber, and the second sample is transported onto the sample stage via the second pre-exhaust chamber, as described in claim 1.

13. The semiconductor processing apparatus according to claim 12, wherein the semiconductor processing apparatus comprises a third arm, the third arm transports the second sample to the second pre-exhaust chamber while the first sample is being processed in the sample chamber, the second pre-exhaust chamber evacuates the inside of the second pre-exhaust chamber containing the second sample while the first sample is being processed in the sample chamber, the first arm performs the first operation and the second arm performs the second operation to exchange the first sample, which has been processed in the sample chamber, with the second sample in the second pre-exhaust chamber, the second pre-exhaust chamber returns the inside of the second pre-exhaust chamber to atmospheric pressure after the second sample has been discharged toward the sample stage, and the third arm discharges the first sample recovered from the sample stage via the second pre-exhaust chamber.

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