JP2014203890A - Transfer apparatus and transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer apparatus and transfer method with which a possibility that a fork is in contact with a substrate to be transferred is detected with high accuracy.SOLUTION: A transfer apparatus 1 for transferring a substrate (eg. wafer) using a fork supporting the substrate comprises: an acceleration detection means 20a-20b attached on a place which is directly connected or indirectly connected to the fork, such as a prescribed part of a fork holder, a prescribed part of a transfer unit, and detecting an acceleration of the fork; and determination means 30 for determining that there is a possibility that the fork is in contact with the substrate when a detected acceleration of the driving fork exceeds an upper limit value. The transfer apparatus 1 preferably further comprises: filter means 30 for transmitting a frequency component of a prescribed frequency band in frequency components of detected acceleration, and determines that there is a possibility that the fork is in contact with the substrate when the acceleration after the frequency component of the prescribed frequency band is transmitted exceeds the upper limit value.

Description

  The present invention relates to a transfer device and a transfer method for transferring a substrate supported by a fork.

  2. Description of the Related Art A transfer device that supports a base such as a semiconductor wafer with a fork and transfers from a transfer source to a transfer destination is known. In the transfer apparatus, when the fork is operating, if the fork contacts the back surface or the front surface of the wafer, the wafer is damaged. By damaging the wafer, fine dust (particles) is generated. Also, the wafer itself may be broken. Since such a wafer becomes a scrap wafer and the yield rate is lowered, it is necessary to minimize the scrap wafer. For example, in the transfer apparatus described in Patent Document 1, a reflective height detection sensor and a reflective horizontal position detection sensor are attached to the fork, and the three-dimensional position of the wafer is moved by each sensor by moving the fork vertically and horizontally. To detect. The fork is operated based on the detection result to transfer the wafer.

JP 11-176907 A

  Even if the fork is moved according to the three-dimensional position of the wafer as in the above transfer device, if the member or fork holding the wafer is deformed, the fork can contact the wafer. There is sex. In particular, when a wafer is processed in a high temperature environment such as a semiconductor heat treatment apparatus, there is a possibility that a member, a fork or the like holding the wafer is deformed. Further, in the transfer apparatus described above, since the fork needs to be moved each time according to the three-dimensional position of each wafer, the processing efficiency is lowered.

  Then, this invention makes it a subject to provide the transfer apparatus and transfer method which can detect the possibility that the fork is contacting the base | substrate of transfer object with high precision.

  The transfer device according to the present invention is a transfer device that supports a fork and transfers a substrate, and is attached to a location that is directly or indirectly connected to the fork, and detects acceleration of the fork. And a determination means for determining that there is a possibility that the fork and the base body are in contact when the acceleration detected by the acceleration detection means exceeds the upper limit value while the fork is operating.

  In this transfer apparatus, the acceleration detection means is attached to a location that is directly or indirectly connected to the fork, and the acceleration detection means detects the acceleration of the fork. Since the acceleration detection means is attached to a place that is directly or indirectly connected to the fork, the vibration of the fork is transmitted to the acceleration detection means, and the acceleration having the frequency component due to the vibration of the fork is detected by the acceleration detection means. . Although the fork vibrates during normal operation, the frequency component due to the vibration is relatively low, and the detected acceleration is also relatively small. However, when the fork comes into contact with the substrate to be transferred during normal operation, it vibrates violently, the frequency component due to the vibration is high, and the detected acceleration also increases. In addition, when the fork comes close to the substrate to be transferred during normal operation (when the clearance between the fork and the substrate is smaller than usual), the fork vibrates vigorously, the frequency component due to the vibration is high, and the detected acceleration is large. Become. The frequency component (acceleration) due to the vibration of the fork during normal operation is clearly different from the frequency component (acceleration) due to the vibration of the fork at the time of contact or in the immediate vicinity of the contact. Therefore, in the transfer device, the determination means determines whether or not the acceleration detected during the operation of the fork exceeds the upper limit value. If the upper limit value is exceeded, the fork may be in contact with the base body. Judge that there is. This upper limit value is a threshold value for determining an acceleration at which the fork may be in contact with the base body, and is set in consideration of an acceleration during normal operation of the fork. As described above, in this transfer apparatus, the acceleration detecting means is attached to a place directly or indirectly connected to the fork, the acceleration of the fork in operation is detected, and the possibility of contact is detected using this acceleration. By determining, the possibility that the fork is in contact with the substrate to be transferred can be detected with high accuracy. As a result, it is possible to minimize the substrate that becomes scrap by contact. Also, contact can be prevented in advance.

  It should be noted that the portion directly or indirectly connected to the fork to which the acceleration detection means is attached includes a predetermined portion of the fork if the acceleration detection means can be attached to the fork itself. The substrate is a substrate to be transferred using a fork, and examples thereof include a wafer, a glass substrate, a solar cell panel, and a flat panel display.

  In the transfer apparatus of the present invention, it is preferable that the acceleration detecting means is attached to a predetermined position of the fork holder that supports the fork or a predetermined position of the transfer mechanism that operates the fork via the fork holder.

  By attaching the acceleration detection means to a predetermined location of the fork holder, the acceleration detection means is attached to a location directly connected to the fork, so that the acceleration due to the vibration of the fork can be accurately detected by the acceleration detection means. In addition, since the acceleration detection means is attached to a place indirectly connected to the fork by attaching the acceleration detection means to a predetermined position of the transfer mechanism that operates the fork via the fork holder, the acceleration detection means Acceleration due to fork vibration can be detected.

  The transfer device according to the present invention further includes a filter unit that passes a frequency component in a predetermined frequency band among the frequency components of the acceleration detected by the acceleration detection unit, and the determination unit passes the frequency component in the predetermined frequency band by the filter unit. It is preferable to determine that there is a possibility that the fork and the base body are in contact when the acceleration after the acceleration exceeds the upper limit value.

  As described above, the frequency component due to the vibration of the fork during normal operation is lower than the frequency component due to the vibration of the fork when the fork comes into contact with the substrate or in the vicinity of the contact, and this low frequency component is the contact frequency of the fork. It becomes a noise component when determining the possibility. Therefore, in the transfer apparatus, the frequency component of the predetermined frequency band is passed through the detected acceleration frequency components by the filter means, and the frequency components other than the predetermined frequency band are removed. This predetermined frequency band is a frequency band equal to or higher than the lower limit frequency for removing frequency components due to vibration of the fork during normal operation or a frequency band equal to or higher than the lower limit frequency and equal to or lower than the upper limit frequency, and is a frequency due to vibration of the fork during normal operation. It is set in consideration of components. In the transfer device, the fork and the base body come into contact with each other when the acceleration after passing the frequency component equal to or higher than the predetermined frequency (after removing the frequency component lower than the predetermined frequency) exceeds the upper limit value by the determination means. It is determined that there is a possibility that As described above, in the transfer device, the determination can be made after performing the filtering process on the detected acceleration, so that the determination can be made using the acceleration from which the frequency component that becomes the noise is removed. It is possible to detect the possibility of being touched with high accuracy.

  In the transfer apparatus according to the present invention, it is preferable that the upper limit value is set in advance using acceleration data of the fork detected when the fork is operated in a state where the fork and the base do not contact each other. The acceleration threshold (upper limit value) for determining the possibility that the fork is in contact with the base body is set by using the acceleration data detected in a state where the fork and the base body are not in contact with each other. A suitable value can be obtained. Further, by determining using this upper limit value, the possibility that the fork is in contact with the base can be determined with high accuracy.

  The transfer method according to the present invention is a transfer method in which a substrate is transferred while being supported by a fork, and the acceleration of the fork is detected by an acceleration detecting means attached to a location connected directly or indirectly to the fork. An acceleration detection step for detecting, and a determination step for determining that there is a possibility that the fork and the base body are in contact when the acceleration detected in the acceleration detection step exceeds an upper limit value while the fork is operating. It is characterized by. In the transfer method according to the present invention, it is preferable that the acceleration detecting means is attached to a predetermined position of the fork holder that supports the fork or a predetermined position of the transfer mechanism that operates the fork via the fork holder. Further, the transfer method of the present invention includes a filtering step of passing a frequency component in a predetermined frequency band among the frequency components of the acceleration detected in the acceleration detecting step, and the determining step includes a frequency in the predetermined frequency band in the filtering step. It is preferable to determine that there is a possibility that the fork and the base body are in contact when the acceleration after passing the component exceeds the upper limit value. In the transfer method of the present invention, it is preferable that the upper limit value is set in advance using acceleration data of the fork detected when the fork is operated in a state where the fork and the base do not contact each other. Each of the above transfer methods has the same function and effect as each of the above transfer devices.

  According to the present invention, the acceleration detecting means is attached to a place that is directly or indirectly connected to the fork, the acceleration of the fork in operation is detected, and the possibility of contact is determined using this acceleration. The possibility that the fork is in contact with the substrate to be transferred can be detected with high accuracy.

It is an example of a fork (state where an acceleration sensor is not attached) of a transfer device concerning this embodiment, and (a) is a side view and (b) is a perspective view. It is a schematic diagram which shows an example at the time of attaching an acceleration sensor to the fork holder of the transfer apparatus which concerns on this Embodiment. It is a block diagram which shows the structure of the contact detection function of the transfer apparatus which concerns on this Embodiment. It is an example of the acceleration data detected with the acceleration sensor during operation | movement of a fork, (a) is raw data, (b) is the data after filtering. It is a flowchart which shows the flow of the contact detection function of the transfer apparatus which concerns on this Embodiment. It is a schematic diagram which shows the positional relationship of the fork and wafer used for experiment. It is an example of the frequency data by the acceleration data detected with the acceleration sensor during the forward movement of a fork, (a) is a case where a fork is a home position, (b) is a case where a fork is a position of +2.0 mm. . It is the result obtained in Experimental example 1 using the X direction acceleration data of the acceleration sensor when the acceleration sensor is attached to the fork holder. It is the result obtained in Experimental Example 2 using the acceleration data in the Y direction of the acceleration sensor when the acceleration sensor is attached to the fork holder. It is the result obtained in Experimental example 3 using the X direction acceleration data of the acceleration sensor when the acceleration sensor is attached to the transfer machine. It is the result obtained in Experimental Example 4 using the acceleration data in the Y direction of the acceleration sensor when the acceleration sensor is attached to the transfer machine. It is the result of having compared the sensitivity obtained in Experimental Examples 1-4. It is the contact determination result obtained in Experimental example 5 which changed the attachment location of the acceleration sensor and the detection direction of the acceleration sensor used for contact determination.

  Embodiments of a transfer device and a transfer method according to the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the transfer apparatus according to the present invention is applied to a transfer apparatus incorporated in a semiconductor heat treatment apparatus. The transfer apparatus according to the present embodiment transfers a wafer from a transfer source (for example, a high heat resistant quartz boat) in a semiconductor heat treatment apparatus to a transfer destination (for example, FOUP) with a fork. In the transfer apparatus according to the present embodiment, in order to transfer a large number of wafers at a high speed in order to improve the throughput, the five wafers arranged at narrow intervals in the vertical direction are transferred as one set.

  Since the transfer source in the semiconductor heat treatment apparatus is a high temperature environment, the member holding the wafer at the transfer source or the fork for transferring the wafer may be deformed by heat. Further, in order to increase the number of wafers processed per batch, the interval (clearance) between the five wafers is very narrow. Therefore, if the deformation due to heat is large, the fork may come into contact with the back surface or the front surface of the wafer during the forward movement operation at the transfer source of the fork or the backward movement operation at the transfer destination.

  When the fork is moving forward or backward, the fork vibrates and the frequency component of the vibration is low. However, when the fork comes into contact with the wafer during forward movement or backward movement, the fork vibrates violently, and a high frequency component is included due to the vibration. In addition, even if the fork moves close to the wafer during forward movement or backward movement (if the clearance between the fork and the wafer becomes smaller than usual), the fork moves at a high speed in the proximity of the fork and the influence of air, etc. The fork vibrates violently and its frequency component is high. The frequency component (acceleration due to vibration) caused by vibration of the fork during normal operation is clearly different from the frequency component (acceleration due to vibration) caused by the vibration of the fork when in contact or in the proximity state immediately before contact.

  With reference to FIGS. 1-3, the transfer apparatus 1 which concerns on this Embodiment is demonstrated. FIG. 1 is an example of the periphery of a fork of a transfer apparatus according to the present embodiment, where (a) is a side view and (b) is a perspective view. FIG. 2 is a schematic diagram showing an example when an acceleration sensor is attached to the fork holder of the transfer apparatus according to the present embodiment. FIG. 3 is a block diagram showing the configuration of the contact detection function of the transfer apparatus according to the present embodiment. FIG. 1 shows a state where no acceleration sensor is attached. Further, as shown in FIG. 1, the forward / backward direction of the fork is the Y direction, the height direction (vertical direction) of the transfer device is the Z direction, and the direction orthogonal to the Y direction and the Z direction is the X direction.

  In the transfer device 1, as a contact detection function, it detects whether or not the fork is in contact with the wafer during normal operation (including the proximity state immediately before contact whether it is in contact or not in contact). If this is detected, an abnormal process is performed. In particular, the transfer apparatus 1 detects acceleration of a fork (acceleration having a frequency component due to vibration of the fork) by attaching an acceleration sensor to a place where the acceleration sensor is connected directly or indirectly in the vicinity of the fork, and the detected acceleration data. Touch detection using.

  The transfer device 1 includes forks 10a to 10e, fork holders 11a to 11e, a transfer machine 12, acceleration sensors 20a to 20e, a transfer machine controller 30, and the like, and in particular, acceleration sensors 20a to 20e as a contact detection function. The transfer machine 12 and the transfer machine controller 30 are used. Further, a higher-level apparatus controller 40 that controls the entire semiconductor manufacturing apparatus (or semiconductor heat treatment apparatus) is connected to the transfer machine controller 30. In the present embodiment, the acceleration sensors 20a to 20e correspond to the acceleration detection means described in the claims, and each process of the contact detection function in the transfer machine controller 30 is the determination means described in the claims. And the filter means.

  The forks 10a to 10e are members for supporting the wafer from the back surface during transfer and carrying the wafer from the transfer source to the transfer destination while the wafer is mounted. The forks 10a to 10e are arranged on the fork holders 11a to 11e, respectively, and are arranged at narrow equal intervals in the vertical direction (vertical direction) in order to simultaneously transfer five wafers in one set. At the time of transfer, each of the forks 10a to 10e moves forward to the back surface of the wafer at the transfer source, rises by the clearance, and receives the wafer from the transfer source holding member. Each of the forks 10a to 10e moves to the transfer destination with the wafer mounted thereon, and moves down to the transfer destination at the transfer destination, transfers the wafer to the holding member, and moves backward. During this forward movement or backward movement, the forks 10a to 10e may come into contact with the back surface or front surface of the wafer. The forward movement or the backward movement is about several seconds and moves about several tens of centimeters. Therefore, the operation is very fast.

  The fork holders 11a to 11e are members for holding the forks 10a to 10e and transmitting the power at the time of transfer by the transfer machine 12 to the forks 10a to 10e. The fork holders 11a to 11e have forks 10a to 10e attached to their tips, respectively, and are equally spaced in the vertical direction so that five wafers can be transferred simultaneously in one set. Further, the fork holders 11 a to 11 e are connected to the transfer machine 12 and operate by power from the transfer machine 12. In the present embodiment, of the fork holders 11a to 11e, four fork holders 11a, 11b, 11d, and 11e are integrally formed. The middle fork holder 11c is formed independently. And four fork holders 11a, 11b, 11d, and 11e operate | move integrally, and only one fork holder 11c can operate | move independently. The fork holder may have other configurations as appropriate.

  The transfer machine 12 is a transfer mechanism for operating the forks 10a to 10e (operations in the front-rear direction, the up-down direction, the left-right direction, and the like) using the fork holders 11a to 11e, and includes a motor (not shown) and a motor To a fork holder 11a to 11e. The transfer machine 12 is provided with fork holders 11a to 11e, and applies power to the fork holders 11a to 11e. Further, when the transfer machine controller 30 is connected to the transfer machine 12 and a command from the transfer machine controller 30 is input, a motor or the like is driven in accordance with the command.

  The acceleration sensors 20a to 20e are sensors that are attached to locations that are directly or indirectly connected to the forks 10a to 10e and detect acceleration due to vibration of the forks 10a to 10e. The portion directly or indirectly connected to the forks 10a to 10e is a portion to which the vibrations of the forks 10a to 10e are transmitted. For example, it is a predetermined place where the fork holders 11a to 11e can be attached, and a predetermined place where the vibrations of the fork holders 11a to 11e (and thus the forks 10a to 10e) can be transmitted and attached in the transfer machine 12. The acceleration sensors 20a to 20e are sensors that can detect accelerations in three directions of the X direction, the Y direction, and the Z direction, respectively. Since the forks 10a to 10e move forward and backward for several seconds, the acceleration sensors 20a to 20e collect sampling data in a predetermined frequency band in order to collect a large amount of acceleration data during these seconds. The sampling frequency is preferably 1000 Hz or more. The acceleration sensors 20a to 20e detect accelerations (voltage values: analog values) at regular intervals according to the sampling rate. The acceleration sensors 20 a to 20 e are connected to the transfer machine controller 30 and output acceleration (voltage value) detected at regular intervals to the transfer machine controller 30. The acceleration sensors 20a to 20e may be sensors that can detect at least one of the X direction and the Y direction.

  With reference to FIG. 2, an example of an attachment location and an attachment method when the acceleration sensors 20a to 20e are attached to the fork holders 11a to 11e will be described. In the case of this example, only the middle acceleration sensor 20c is attached to the opposite side, so that it is not shown in FIG. The acceleration sensors 20a to 20e include a sensor main body 20A and an electric circuit board 20B. In this example, the acceleration sensors 20a to 20e are attached to the side surfaces of the fork holders 11a to 11e using bolts on the side surfaces of the fork holders 11a to 11e (see FIG. 1). Therefore, holders 21a to 21e for attaching acceleration sensors having the same thickness as the fork holders 11a to 11e are prepared. Each of the attachment holders 21a to 21e has a predetermined length, and has a width capable of sufficiently mounting the electric circuit board 20B of the acceleration sensors 20a to 20e. The length of each holder is such that the attachment holder 21b is longer than the attachment holder 21a so that the acceleration sensor 20b does not contact the upper attachment holder 21a. Further, the attachment holder 21e is made longer than the attachment holder 21d so that the acceleration sensor 20e does not contact the upper attachment holder 21d. The holder 21c (not shown) for attaching the acceleration sensor 20c on the opposite side may have an arbitrary length. The attachment holders 21a to 21e are fixed to the side surfaces of the fork holders 11a to 11e with a plurality of bolts 22, respectively. The electric circuit boards 20B of the acceleration sensors 20a to 20e are attached to the upper surfaces of the attachment holders 21a to 21e, and a heat-resistant cover 23 that covers the entire acceleration sensors 20a to 20e from above is covered and screwed. The electric circuit boards 20B of the acceleration sensors 20a to 20e are wired using the heat-resistant tubes 24, respectively.

  FIG. 4A shows an example of time-series data (raw data) of acceleration detected by the acceleration sensor 20, where the horizontal axis is time and the vertical axis is acceleration. This time-series data of acceleration is, for example, data detected for several seconds during the forward movement of the fork 10. The time series data of acceleration includes acceleration composed of a relatively low frequency component when the fork 10 vibrates by forward movement, and this acceleration is relatively small. In addition, when the fork 10 is in contact with the wafer or just before the contact, the acceleration time series data includes an acceleration composed of a high frequency component when the fork 10 vibrates vigorously due to the contact or contact. This acceleration is great.

  The transfer machine controller 30 includes a microcomputer and various memories. The transfer machine controller 30 executes each process such as a transfer control function and a contact detection function by executing an application program with a microcomputer. In the present embodiment, the processing of the contact detection function in the transfer machine controller 30 will be described in detail. In order to carry out each process of this contact detection function, the transfer machine controller 30 is connected to acceleration sensors 20a to 20e, and acceleration (voltage value: analog value) is sent from the acceleration sensors 20a to 20e at regular intervals. Enter each. Further, the transfer machine 12 is connected to the transfer machine controller 30 and outputs a command to the transfer machine 12 as necessary. In addition, the transfer machine controller 30 outputs an alarm notification to the apparatus controller 40 as necessary. When this alarm notification is input, the device controller 40 generates an alarm sound from the alarm 40a.

  The contact detection function will be described. The transfer machine controller 30 performs the following processing on the acceleration data of each acceleration sensor 20a to 20e. Moreover, in the transfer machine controller 30, you may perform the following processes using the data of both the X direction and the Y direction among the acceleration data of the three directions of the acceleration sensors 20a to 20e, or the X direction and the Y direction. The following processing may be performed using only data in one direction. Note that data in the Z direction may also be used.

In the transfer machine controller 30, every time acceleration (voltage: analog value) is input, it is converted into a digital value. Furthermore, the transfer machine controller 30 converts the acceleration voltage value into a G value (or [m / sec ² ] value). The acceleration value processed below may be left as a voltage value without being converted into a G value or the like. It should be noted that the start / end of collection of time series data of acceleration is matched with an operation event (for example, forward movement or backward movement of the fork 10) that may come into contact with the wafer while the fork 10 is operating in the transfer apparatus 1. Executed. Alternatively, the time series data of the acceleration in the corresponding section may be extracted by associating the time stamp of the time series data of the acceleration with the time stamp of the operation event of the transfer device 1.

  The transfer machine controller 30 performs filtering on the time series data of the acceleration that has been collected. In this filtering, when a contact is detected, vibration of a low frequency component due to normal operation of the fork 10 (for example, forward operation and backward operation) becomes noise, and therefore, a predetermined frequency or more of frequency components included in time series data of acceleration. Only the frequency component is passed (removes the frequency component less than the predetermined frequency: high-pass filter). This predetermined frequency is set in advance by experiments or the like in consideration of a low frequency component due to the normal operation of the fork 10. The predetermined frequency is, for example, a frequency of 200 to 1000 Hz, and a high frequency of 500 Hz or 1000 Hz is desirable if data can be collected at high speed. In addition, since very high frequency components also become noise, filtering may pass only frequency components not less than a predetermined frequency and not more than the upper limit frequency among the frequency components included in the acceleration data (bandpass filter).

  FIG. 4B shows acceleration time series data after filtering the acceleration time series data (raw data) of FIG. This time series data of acceleration has a smaller value than the time series data (raw data) of acceleration in FIG. 4A because low frequency components are removed. As described above, when the fork 10 comes into contact with the wafer or comes close to the contact, it vibrates violently, the frequency component due to the vibration is high, and the detected acceleration also increases. If the acceleration after filtering in FIG. 4B exceeds a predetermined value, it can be determined that the fork 10 is in contact with the wafer or close to the contact.

  In the transfer machine controller 30, in order to determine whether the fork 10 is in contact with the wafer (including the proximity state immediately before the contact), it is determined whether or not the acceleration exceeds the upper limit value using the acceleration data after filtering. judge. This upper limit value is a threshold value for determining acceleration due to vibration of a high frequency component that occurs when the fork 10 is in contact with the wafer during normal operation or is in the proximity of the contact. When determining that the acceleration has exceeded the upper limit value, the transfer machine controller 30 determines that the fork 10 is in contact with the wafer (including the proximity state immediately before the contact). Then, the transfer machine controller 30 outputs an alarm notification to the apparatus controller 40 and outputs a command to the transfer machine 12 to stop the fork 10 (fork holder 11). With this alarm notification, the device controller 40 generates an alarm sound from the alarm 40a. Here, not only the fork 10 whose contact has been detected, but also a set of five forks 10a to 10e are all stopped. In addition, in the transfer machine controller 30, when the data of both X direction and Y direction are used, it determines based on the determination result of two directions. For example, the transfer machine controller 30 determines that the fork 10 is in contact with the wafer when it is determined in both directions that the upper limit value has been exceeded. If it is determined that the upper limit has been exceeded in either direction, it is determined that the fork 10 is in contact with the wafer.

  The upper limit value is set in advance using acceleration time-series data collected by experiments. In this experiment, after confirming that the fork 10 is not in contact with the wafer, the fork 10 is normally operated to collect time series data of acceleration. Then, the maximum value is extracted from the time series data after filtering by performing the above filtering on the time series data of the acceleration. This process is performed a predetermined number of times or more (the number of times is better to some extent). Then, a statistical value such as an average value and a standard deviation of the maximum value is calculated. The upper limit value is set using this statistical value. For example, the upper limit value is an average value + 3 × standard deviation. Note that the upper limit value may be different for each direction in the X direction and the Y direction, or may be the same value.

  The operation of the contact detection function in the transfer device 1 will be described with reference to the flowchart of FIG. FIG. 5 is a flowchart showing the flow of the contact detection function of the transfer apparatus according to the present embodiment. In the transfer apparatus 1, the following operations are repeated at regular intervals.

  The fork holders 11a to 11e to which the vibrations of the forks 10a to 10e are directly or indirectly transmitted or the acceleration sensors 20a to 20e attached to the transfer machine 12 respectively detect the vibrations of the forks 10a to 10e as accelerations. Then, the detected acceleration (voltage value) is output to the transfer machine controller 30 (S1). In the transfer machine controller 30, the accelerations (voltage values) of the forks 10a to 10e are input from the acceleration sensors 20a to 20e, respectively.

  For each acceleration data of each of the forks 10a to 10e, the transfer machine controller 30 performs filtering (high pass or band pass) on the acceleration data (S2). Then, the transfer machine controller 30 determines whether or not the acceleration after filtering exceeds the upper limit value (S3). When it is determined in S3 that the upper limit value has been exceeded, the transfer machine controller 30 determines that there is a possibility of contact (S4), and outputs an alarm notification to the apparatus controller 40 and forks to the transfer machine 12 A command to stop 10 (fork holder 11) is output (S5). In the transfer machine 12, all the fork holders 11a to 11e (and eventually the forks 10a to 10e) are stopped (S5). At this time, the operator notices the alarm sound, checks whether or not the member holding the wafer is deformed, and performs necessary measures when the deformation is found. If it is determined in S3 that the upper limit value has not been exceeded, the transfer machine controller 30 determines that there is no contact, and ends the current process (S6).

  According to the transfer device 1, the acceleration sensor 20 is attached to a location that is directly or indirectly connected to the fork 10 to detect the acceleration of the fork 10 during normal operation. By determining the possibility of contact using this acceleration, the possibility that the fork 10 is in contact with the wafer can be detected with high accuracy. As a result, scrap wafers can be minimized. In particular, contact can be prevented in advance when the proximity state immediately before contact can be detected.

  Further, according to the transfer device 1, the low frequency component due to the normal operation of the fork 10 can be removed by performing high-pass filter processing (or band-pass filter processing) on the acceleration data detected by the acceleration sensor 20. it can. And it can judge using the acceleration from which the low frequency component used as noise was removed, and the possibility that the fork 10 is contacting the wafer can be detected with higher accuracy.

  Moreover, according to the transfer apparatus 1, the fork 10 is brought into contact with the wafer by setting an upper limit value using a statistical value obtained from acceleration data detected in a state where the fork 10 and the wafer are not in contact with each other. A suitable value can be obtained as the upper limit value for determining the possibility of being present. By determining using this upper limit value, the possibility that the fork 10 is in contact with the wafer can be determined with high accuracy.

  With reference to FIGS. 6 to 12, Experimental Examples 1 to 4 performed using the transfer device 1 will be described. FIG. 6 is a schematic diagram showing the positional relationship between a fork and a wafer used in the experiment. FIG. 7 shows an example of frequency data based on acceleration data detected by the acceleration sensor during the forward movement of the fork. (A) shows the case where the fork is at the home position, and (b) shows the position where the fork is +2.0 mm. This is the case. FIG. 8 shows the results obtained in Experimental Example 1 using the X-direction acceleration data of the acceleration sensor when the acceleration sensor is attached to the fork holder. FIG. 9 shows the result obtained in Experimental Example 2 using the acceleration data in the Y direction of the acceleration sensor when the acceleration sensor is attached to the fork holder. FIG. 10 shows the results obtained in Experimental Example 3 using X-direction acceleration data of the acceleration sensor when the acceleration sensor is attached to the transfer machine. FIG. 11 shows the results obtained in Experimental Example 4 using the acceleration data in the Y direction of the acceleration sensor when the acceleration sensor is attached to the transfer machine. FIG. 12 shows the results of comparing the sensitivities obtained in Experimental Examples 1 to 4.

  In this experiment, as shown in FIG. 6, an operation event for advancing the fork 10 to receive the wafer W held by the holding member Ba of the quartz boat B was targeted. The holding member Ba and the fork 10 of the quartz boat B are in a normal state without any deformation. The fork 10 used the top fork 10a, and used acceleration data detected by the acceleration sensor 20a. The acceleration sensor used in the experiment is a KXM52-1050 triaxial acceleration sensor (response frequency: 10 to 1500 Hz) manufactured by Kionics. The acceleration data was collected using a NR-600 multi-input data collection system (maximum sampling frequency of 100 kHz) manufactured by Keyence Corporation. In this experiment, all acceleration data collected in the motion event of the forward movement of the fork 10 is used, and the maximum value is extracted from this acceleration data. Incidentally, although actual contact detection in the transfer device 1 is real-time processing, since it is not real-time processing in the experiment, the maximum value of all acceleration data during forward movement is used.

  In Experimental Examples 1 to 4, the mounting location of the acceleration sensor 20 (fork holder 11 and transfer machine 12) and the combination of the acceleration sensor 20 with different detection directions (X direction and Y direction) of the acceleration time series data were changed. There are four experimental examples. In Experimental Examples 1 to 4, the position of the fork holder 11 is adjusted by the transfer machine 12, and the position of the fork 10 is changed to the home position (designed normal position) as shown in FIG. An experiment was conducted by moving the fork 10 forward at four positions of +1.8 mm, +2.0 mm, and +2.3 mm. When the home position is +1.8 mm or +2.0 mm from the home position, the fork 10 does not come into contact with the wafer W during the forward movement, and when it is +2.3 mm from the home position, the fork 10 is moved during the forward movement. To touch.

  Incidentally, FIG. 7 shows the result of analyzing the frequency component included in the acceleration data detected by the acceleration sensor 20 when the acceleration sensor 20 is attached to the fork holder 11. The horizontal axis is time, and the vertical axis is frequency (represents a frequency component in which a dark portion is generated). As shown in FIG. 7A, when the fork 10 is at the home position, only a low frequency component is generated. On the other hand, as shown in FIG. 7B, when the fork 10 is +2.0 mm from the home position, the fork 10 is not in contact with the wafer W, but a high frequency component is generated. Therefore, by performing appropriate filtering, contact detection is possible even at positions of +1.8 mm and +2.0 mm that are not in contact.

  The experimental results of Experimental Examples 1 to 4 in FIGS. 8 to 11 described below are the raw data of acceleration detected by the acceleration sensor 20 in FIGS. (A) to (d) (FIG. (A) is the home position). , Data when the figure (b) is +1.8, data when the figure (c) is +2.0 mm, data when the figure (d) is +2.3 mm), figures (e) to (H) is the data after filtering the raw acceleration data (band pass filter of 500 to 5000 Hz) (FIG. (E) is the data in the case of the home position, and (f) is the data in the case of +1.8.) (G) is data when +2.0 mm, FIG. (H) is data when +2.3 mm), and FIG. (I) shows each sensitivity for +1.8 mm, +2.0 mm, and +2.3 mm. It is. In the drawings (a) to (h), the horizontal axis represents time, and the vertical axis represents acceleration. In FIG. (I), the horizontal axis represents +1.8 mm, +2.0 mm, and +2.3 mm, and the vertical axis represents sensitivity at each position = (maximum acceleration at each position / acceleration at the home position). The sensitivity on the left side (white bar graph) is the raw acceleration data, and the sensitivity on the right side (black bar graph) is the data after filtering. For example, in the case of the raw data in FIG. 8, since the maximum acceleration value at the home position is 0.233, the sensitivity is 3.87 (= 0 when the maximum acceleration value is 0.902 and +1.8 mm. .902 / 0.233), the sensitivity is 6.89 (= 1.606 / 0.233) and the maximum value of acceleration is 1.703 when the maximum value of acceleration is 1.606 +2.0 mm. In the case of +2.3 mm, the sensitivity is 7.31 (= 1.703 / 0.233). It should be noted that the acceleration of the raw data and the acceleration of the filtered data indicated by the experimental results are values adjusted in the experiment and do not indicate units. The experimental results of Experimental Examples 1 to 4 are the results of one experiment.

  The experimental condition of Experimental Example 1 is the case where the acceleration sensor 20 is attached to the fork holder 11 and acceleration time series data in the X direction of the acceleration sensor 20 is used. The experimental results for Experimental Example 1 are shown in FIG. In the case of the raw data at the home position shown in FIG. 8A, the vibration is a low frequency component due to the forward movement of the fork 10, the acceleration is also a small value, and the maximum value extracted from the raw data is 0. 233. In the case of the raw data at +1.8 mm shown in FIG. 8B, since the fork 10 includes vibration of a high frequency component due to a forward movement operation in the proximity of the wafer W just before contact, a value having a large acceleration locally. The maximum value extracted from the raw data is 0.902. In the case of the raw data at +2.0 mm shown in FIG. 8C, the vibration of the high frequency component due to the forward movement when the fork 10 is further in the close state is included, and the acceleration becomes a locally larger value. The maximum value extracted from is 1.606. In the case of the raw data at +2.3 mm shown in FIG. 8D, vibrations of high frequency components due to the forward movement with the fork 10 in contact with the wafer W are included, and the acceleration is locally large. The maximum value extracted from the raw data is 1.703. In the case of the data after filtering at the home position shown in FIG. 8E, since the low frequency component is removed, the acceleration becomes a small value, and the maximum value extracted from the data after filtering is 0.185. In the case of the data after filtering at +1.8 mm shown in FIG. 8 (f), the low frequency component is removed, but the vibration of the high frequency component due to the forward movement in the proximity state just before the contact is included. The maximum value extracted from the filtered data is 0.837. In the case of the data after filtering at +2.0 mm shown in FIG. 8 (g), the low frequency component is removed, but the vibration of the high frequency component due to the forward movement in the close state is further included, so the acceleration is further locally increased. The maximum value extracted from the filtered data is 1.400. In the case of the raw data at +2.3 mm shown in FIG. 8 (h), the low frequency component is removed, but the vibration of the high frequency component due to the forward movement in the contacted state is included, so the acceleration is locally increased. Thus, the maximum value extracted from the filtered data is 1.661. In the sensitivity comparison shown in FIG. 8 (i), the sensitivity of the data after filtering is higher than that of the raw data, and the sensitivity increases when the fork 10 comes closer to the wafer W even when it is not in contact. The state is more sensitive. From the experimental results of Experimental Example 1, the closer the fork 10 is to the wafer W, the greater the vibration, but the phenomenon is not simple (interference over several times). Even when the fork 10 is not in contact with the wafer W, the sensitivity increases as the proximity of the fork 10 to the wafer W increases. In addition, the filtered data is more sensitive than the raw data, and is suitable for contact detection.

  The experimental condition of Experimental Example 2 is the case where the acceleration sensor 20 is attached to the fork holder 11 and acceleration time series data in the Y direction of the acceleration sensor 20 is used. Compared with Experimental Example 1, Experimental Example 2 uses data in the same direction as the forward direction of the fork 10 because the acceleration time series data is in the Y direction. The experimental results for Experimental Example 2 are shown in FIG. In the case of raw data at the home position shown in FIG. 9A, the maximum value is 0.318. In the case of raw data at +1.8 mm shown in FIG. 9B, the maximum value is 1.522. In the case of the raw data at +2.0 mm shown in FIG. 9C, the maximum value is 1.950. In the case of raw data at +2.3 mm shown in FIG. 9D, the maximum value is 1.896. In the case of data after filtering at the home position shown in FIG. 9 (e), the maximum value is 0.198. In the case of the data after filtering at +1.8 mm shown in FIG. 9F, the maximum value is 1.572. In the case of data after filtering at +2.0 mm shown in FIG. 9G, the maximum value is 2.008. In the case of raw data at +2.3 mm shown in FIG. 9 (h), the maximum value is 1.850. In the sensitivity comparison shown in FIG. 9 (i), the sensitivity of the filtered data is higher than that of the raw data, and the sensitivity increases when the fork 10 approaches the wafer W even when it is not in contact. The sensitivity is higher in the non-contact state than in the present state (however, this is a result of one experiment). From the experimental result of the experimental example 2, the same conclusion as that of the experimental example 1 can be obtained. Furthermore, since the Y direction is the same as the forward direction of the fork 10, vibration due to acceleration / deceleration of the motor of the transfer machine 12 can be canceled by filtering. As a result, using the acceleration time series data in the Y direction has higher sensitivity in the proximity state just before the contact than using the acceleration time series data in the X direction.

  The experimental condition of Experimental Example 3 is the case where the acceleration sensor 20 is attached to the transfer machine 12 and the acceleration sensor 20 is acceleration time-series data in the X direction. Since Experimental Example 3 is attached to the transfer machine 12 as compared with Experimental Example 1, the number of members interposed between the acceleration sensor 20 and the fork 10 is increased, and detection is performed at a position far from the fork 10. Therefore, it is difficult for vibration of the fork 10 to be transmitted to the acceleration sensor 20. The experimental results for Experimental Example 3 are shown in FIG. In the case of raw data at the home position shown in FIG. 10 (a), the maximum value is 0.355. In the case of the raw data at +1.8 mm shown in FIG. 10B, the maximum value is 0.407. In the case of the raw data at +2.0 mm shown in FIG. 10C, the maximum value is 0.806. In the case of raw data at +2.3 mm shown in FIG. 10 (d), the maximum value is 1.877. In the case of the data after filtering at the home position shown in FIG. 10 (e), the maximum value is 0.261. In the case of the data after filtering at +1.8 mm in FIG. 10F, the maximum value is 0.431. In the case of the data after filtering at +2.0 mm in FIG. 10G, the maximum value is 0.760. In the case of raw data at +2.3 mm in FIG. 10 (h), the maximum value is 1.985. In the sensitivity comparison of FIG. 10 (i), the sensitivity of the filtered data is higher than that of the raw data, and the sensitivity increases when the fork 10 approaches the wafer W even in a non-contact state (however, the fork holder Sensitivity is lower than in the case of attaching to 11), and the sensitivity in the contacted state is clearly higher than in the non-contacting state. From the experimental result of the experimental example 3, the same conclusion as that of the experimental example 1 can be obtained. However, the sensitivity is clearly lower in the state where the contact is not made than in the case where the fork holder 11 is attached. Therefore, it is difficult to detect the contact state at +1.8 mm (also +2.0 mm depending on the upper limit setting).

  The experimental condition of Experimental Example 4 is the case where the acceleration sensor 20 is attached to the transfer machine 12 and acceleration time series data in the Y direction of the acceleration sensor 20 is used. Compared to Experimental Example 1, Experimental Example 4 uses data in the same direction as the forward direction of the fork 10 because the acceleration time series data is in the Y direction, and is attached to the transfer machine 12, so the acceleration sensor 20 and the fork 10 The number of members interposed between the forks 10 increases, and detection is performed at a position far from the fork 10. The experimental results for Experimental Example 4 are shown in FIG. In the case of raw data at the home position shown in FIG. 11 (a), the maximum value is 0.569. In the case of the raw data at +1.8 mm shown in FIG. 11B, the maximum value is 0.572. In the case of the raw data at +2.0 mm shown in FIG. 11C, the maximum value is 0.924. In the case of raw data at +2.3 mm shown in FIG. 11 (d), the maximum value is 1.758. In the case of the data after filtering at the home position shown in FIG. 11 (e), the maximum value is 0.423. In the case of the data after filtering at +1.8 mm shown in FIG. 11F, the maximum value is 0.520. In the case of the data after filtering at +2.0 mm shown in FIG. 11 (g), the maximum value is 0.626. In the case of raw data at +2.3 mm shown in FIG. 11 (h), the maximum value is 1.448. In the sensitivity comparison shown in FIG. 11 (i), the sensitivity of the filtered data is higher than that of the raw data (however, the opposite is true when +2.0 mm). As the distance approaches, the sensitivity increases (however, the sensitivity is lower than when attached to the fork holder 11), and the sensitivity in the contacted state is clearly higher than in the non-contacted state. From the experimental result of the experimental example 4, the same conclusion as that of the experimental example 3 can be obtained. Furthermore, since the Y direction is the same as the forward direction of the fork 10, vibration due to acceleration / deceleration of the motor of the transfer machine 12 can be canceled by filtering.

  FIG. 12 shows a comparison of the sensitivities of Experimental Examples 1 to 4, where the horizontal axis represents +1.8 mm, +2.0 mm, and +2.3 mm, and the vertical axis represents the sensitivity at each position. FIG. 4A shows the case of data in the X direction, and FIG. 6B shows the case of data in the Y direction. The leftmost sensitivity (white bar graph) at each position is attached to the transfer machine 12 and is the raw acceleration data. The second sensitivity from the left (black bar graph) is attached to the transfer machine 12. This is the case of data after filtering, the third sensitivity from the left (hatched bar flag) is attached to the fork holder 11 and is the raw acceleration data, and the rightmost sensitivity (horizontal bar graph) is the fork holder. 11 is a case of data after being attached and filtered.

  As can be seen from FIG. 12, the post-filtering data is more sensitive than the raw data. The attachment to the fork holder 11 has better sensitivity than the attachment to the transfer machine 12, and in particular, the sensitivity in the state of no contact with the transfer machine 12 is lowered. In the case of attachment to the transfer machine 12, the X direction data is more sensitive. The most sensitive is when the data after filtering is attached to the fork holder 11 and used. In particular, the sensitivity is better when data in the Y direction is used. By making contact determination under such a high sensitivity condition, a determination result with higher accuracy can be obtained.

  Experimental example 5 performed using the transfer apparatus 1 will be described. In Experimental Example 5, the fork 10 was moved forward at a position +1.8 mm from the home position, and X-direction data and Y-direction data of raw data and X-direction data and Y-direction data after filtering were used. In Experimental Example 5, the same experiment was performed 10 times, and contact determination based on the upper limit value was performed on the maximum value extracted from the raw data and the filtered data for each time. The contact determination result is shown in FIG. The upper limit value is extracted from the acceleration time series data (after raw data and filtering) for 10 times obtained when the fork 10 is at the home position (not in contact). The average value and the standard deviation were calculated from the maximum value, and the average value + 3 × standard deviation was taken as the upper limit value.

  As shown in FIG. 13, in the case of attachment to the transfer machine 12, in the case of raw data in the X direction, it is determined that the contact is 8 times out of 10 times. In the case of data after filtering in the X direction, it was determined that the contact was 8 times out of 10 times, and in the case of data after filtering in the Y direction, it was determined that the contact was 7 times out of 10 times. In the case of attachment to the fork holder 11, in the case of raw data in the X direction, it is determined that the contact is 10 times out of 10 times, and in the case of raw data in the Y direction, it is determined that the contact is 10 times out of 10 times. In the case of the data after filtering, it was determined that the contact was 10 times out of 10. In the case of the data after filtering in the Y direction, it was determined that the contact was 10 times out of 10. Accordingly, even in this experimental result, contact determination can be made with high accuracy when the data after filtering attached to the fork holder 11 is used. In particular, although it is in the state of not contacting at +1.8 mm, it can be determined that there is a possibility of contact.

  From the experimental results of Experimental Examples 1 to 4 and the experimental result of Experimental Example 5, when using data that is attached and filtered to the fork holder 11 directly connected to the fork 10, the possibility of contact with the highest accuracy can be determined. . In particular, contact detection is possible even when the fork 10 is not in contact with the wafer. Furthermore, even if the fork 10 is closer to the wafer, the contact is more easily detected even in a non-contact state.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the present invention is applied to a transfer device of a semiconductor heat treatment apparatus, but can be applied to various other transfer devices using a fork. In this embodiment, the substrate to be transferred is applied to a semiconductor wafer. However, it can be applied to other substrates transferred by a fork such as a glass substrate, a solar cell panel, and a flat panel display.

  In the present embodiment, the present invention is applied to the case where five wafers arranged in the vertical direction are transferred as one set. However, the present embodiment is also applicable to the case where other than five wafers are transferred as one set. Alternatively, the present invention may be applied when transferring a single wafer.

  Further, in the present embodiment, the acceleration sensor is attached to a predetermined location of the fork holder or the transfer machine. However, the acceleration sensor is a location that is directly or indirectly connected to the fork and may be any location where vibration of the fork is transmitted. Or a predetermined location on the fork if the fork itself has a space for mounting the acceleration sensor.

  In the present embodiment, the time series data of the detected acceleration is filtered, and contact determination is performed using the data after the filtering process. However, the time series data (raw data) of the detected acceleration is filtered. You may perform contact determination, without processing.

  Moreover, although an example of the setting method of the upper limit value is shown in the present embodiment, the upper limit value may be set by another method.

  In this embodiment, the fork collects acceleration time-series data during an operation event and performs contact detection in real time. However, after the operation event ends, all the acceleration time-series data in the operation event are used for contact. It is good also as a structure which performs a detection. Even in this case, when contact is detected, a measure for preventing contact can be taken from the next operation event.

  Further, in the present embodiment, the transfer controller is configured to perform contact detection, but may be performed elsewhere as long as the detection value of the acceleration sensor can be taken in, for example, an apparatus controller that controls the entire semiconductor manufacturing apparatus. A separate computer such as a personal computer incorporating a contact detection application.

  DESCRIPTION OF SYMBOLS 1 ... Transfer apparatus, 10, 10a-10e ... Fork, 11, 11a-11e ... Fork holder, 12 ... Transfer machine, 20, 20a-20e ... Accelerometer, 20A ... Sensor main body, 20B ... Electric circuit board, 21 , 21a to 21e ... Mounting holder, 22 ... Bolt, 23 ... Heat-resistant cover, 24 ... Heat-resistant tube, 30 ... Transfer machine controller, 40 ... Device controller, 40a ... Alarm.

Claims (8)

A transfer device that supports a fork and transfers a substrate,
Acceleration detection means attached to a location that is directly or indirectly connected to the fork and detecting the acceleration of the fork;
A determination unit that determines that the fork and the base may be in contact with each other when an acceleration detected by the acceleration detection unit exceeds an upper limit value during operation of the fork;
A transfer apparatus comprising:   The transfer according to claim 1, wherein the acceleration detecting means is attached to a predetermined position of a fork holder that supports the fork or a predetermined position of a transfer mechanism that operates the fork via the fork holder. Mounting device. Filter means for passing a frequency component of a predetermined frequency band among frequency components of acceleration detected by the acceleration detection means;
The determination means determines that there is a possibility that the fork and the base body are in contact with each other when an acceleration after passing a frequency component of a predetermined frequency band by the filter means exceeds an upper limit value. The transfer device according to claim 1 or 2, characterized in that   The upper limit value is set in advance using acceleration data of the fork detected when the fork is operated in a state where the fork and the base body are not in contact with each other. 4. The transfer device according to any one of 3 above. A transfer method for transferring a substrate supported by a fork,
An acceleration detection step of detecting acceleration of the fork by means of acceleration detection means attached to a location that is directly or indirectly connected to the fork;
A determination step of determining that there is a possibility that the fork and the base are in contact with each other when the acceleration detected in the acceleration detection step exceeds an upper limit value while the fork is operating;
The transfer method characterized by including.   The said acceleration detection means is attached to the predetermined location of the fork holder which supports the said fork, or the predetermined location of the transfer mechanism which operates the said fork via the fork holder. Transfer method. Including a filter step of passing a frequency component of a predetermined frequency band among the frequency components of the acceleration detected in the acceleration detection step,
In the determination step, it is determined that there is a possibility that the fork and the base body are in contact when an acceleration after passing a frequency component of a predetermined frequency band in the filtering step exceeds an upper limit value. The transfer method according to claim 5 or 6, wherein the transfer method is characterized.   6. The upper limit value is set in advance using acceleration data of the fork detected when the fork is operated in a state where the fork and the base do not contact each other. 8. The transfer method according to any one of 7 above.