JP2005066771A - Robot system for carrying substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate carry-out method for a carrying robot low in cost with a short process time for intermittent operation. <P>SOLUTION: This robot system for carrying substrates for carrying out the substrates 3 enclosed in a storage cassette 1, from the storage cassette 1 equipped with a plurality of racks 2 for housing a plurality of substrates 3, has the carrying robot 4 for carrying out the substrates 3 enclosed in the storage cassette 1, from the storage cassette 1, and a control device for controlling the carrying robot 4. The carrying robot 4 is equipped with a hand 5 at an arm distal end to grip the substrate 3. The hand 5 is provided with a sensor 6 capable of detecting the presence of the substrate 3. The control device 7 has a storage device 8 storing a working program describing carry-out processing for the substrates 3 enclosed in the lowermost stage rack 2 of the storage cassette 1, the height of one stage portion of the rack 2, and the number of all the stages of the racks 2; and an arithmetic unit 9 for performing the shift operation for the suction position of the substrates 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a robot system including a transfer robot, and more particularly, to a substrate transfer robot system that takes out and transfers a thin substrate such as a liquid crystal substrate or a wafer from a storage cassette in which these substrates are stored.

  In a semiconductor or liquid crystal manufacturing process, a thin substrate such as a liquid crystal substrate or a wafer, which is an object to be processed, is stored in a storage cassette and conveyed between processing apparatuses in each process. The storage cassette is a box-shaped container that stacks and stores a large number of thin substrates, and has a large number of shelf-like grooves cut on the inner wall. One thin substrate is placed in each rack formed by the plurality of grooves. By inserting the sheets one by one, the thin substrates stacked one above the other are prevented from contacting each other. When the storage cassette arrives at each step in the manufacturing process, the transfer robot unloads the thin substrates one by one from the storage cassette, loads them into the processing apparatus of the process, and completes predetermined processing in the processing apparatus. The robot unloads the thin substrate from the processing apparatus, and loads it into the storage cassette again.

  In an apparatus that takes out and conveys thin substrates stacked and stored in multiple stages in such a storage cassette one by one using a transfer robot, conventionally, before the substrate unloading process, the storage condition of the substrates stored in the storage cassette is determined. That is, it is known whether or not a substrate is stored in each rack. This is because, by grasping the storage condition of the substrate before the unloading process, the transfer robot skips the rack that does not store the substrate and performs the unloading process only for the rack that stores the substrate. Because you can.

Conventionally, as means for detecting the presence / absence of a substrate in a rack, a method of detecting the presence / absence of a substrate in each rack by moving a reflective sensor in front of the storage cassette (for example, Patent Document 1), all of the storage cassettes are used. A method for detecting the presence or absence of a substrate in each rack by providing a sensor in the rack, and a method for detecting the presence or absence of a substrate in each rack by photographing the rack with a CCD camera and image processing the image (for example, Patent Documents) 2).
JP-A-10-242249 Japanese Patent Application Laid-Open No. 2002-224982

  However, in the method of moving the reflective sensor disclosed in Patent Document 1 in front of the storage cassette, a detection step of the substrate in the storage cassette is required before the substrate unloading step, which increases the tact time. There is a problem. Further, in the method of providing sensors in all the racks of the storage cassette described above, the detection process of the substrate in the storage cassette is unnecessary, but there is a problem that the cost is increased because sensors for the number of stages of the rack are required. is there. Furthermore, the method of processing an image obtained by photographing a rack with the CCD camera disclosed in Patent Document 2 has a problem that an expensive CCD camera is required, which increases the cost, and advanced technology for image processing. Necessary.

  The present invention has been made to solve the problems of the related art, and an object of the present invention is to provide a substrate transfer robot system having a short tact time and a low cost.

  In order to achieve the above-described object, in the invention according to claim 1, substrate transport for unloading a substrate stored in a storage cassette having a plurality of racks for storing a plurality of substrates from the storage cassette. The robot system has the following configuration. That is, the substrate transfer robot system includes a transfer robot that unloads the substrate stored in the storage cassette from the storage cassette, and a control device that controls the transfer robot. Among these, the transfer robot is equipped with a hand capable of gripping the substrate at the tip of the arm, and the hand includes a sensor capable of detecting the presence or absence of the substrate in the rack. On the other hand, the control device includes a storage device that stores a work program in which a carry-out process for a substrate stored in the bottom rack of the storage cassette is described, the height of one rack, and the total number of racks; And an arithmetic unit that performs a shift operation on the adsorption position of the substrate. It is assumed that the plurality of racks included in the storage cassette are arranged at equal intervals with a height of one stage of the racks stored in the storage device.

  According to the first aspect of the present invention, when the transfer robot enters the storage cassette in order to carry out the substrate, the robot operates according to the work program stored in the storage device. This work program describes an unloading process for a substrate stored in the lowermost rack of the storage cassette. Then, in accordance with this work program, in order for the transfer robot to pick up a substrate that may be stored in the bottom rack, the suction position for the substrate stored in the bottom rack specified in the work program Will work towards. In this process, if the sensor provided in the hand detects that the substrate is stored in the lowermost rack, the unloading process is performed on the substrate stored in the lowermost rack. After the carry-out process for the substrates stored in the lowermost rack is completed, the transfer robot operates again according to the work program and performs the substrate detection / carry-out process for the other racks of the storage cassette.

  On the other hand, when the sensor provided in the hand does not detect that the substrate is stored in the lowermost rack in the above-described process, the following processing is performed. In this case, since it is known that the substrate is not stored in the lowermost rack, the hand is moved to the next rack, that is, the second rack from the bottom. Specifically, as described above, since the transfer robot moves toward the suction position, the suction position is changed from the current position relative to the lowest rack to the position relative to the second rack. Specifically, the suction position for the lowermost rack and the suction position for the second rack are different by the height of one rack, so the storage device stores the height of one rack in advance. Keep it. If the sensor provided in the hand does not detect that the substrate is stored in the lowermost rack, the computing device uses the first stage of the rack at the current suction position, that is, the suction position relative to the lowermost rack. A so-called shift calculation is performed to obtain the suction position for the second rack by adding the heights of minutes.

  The transfer robot operates toward the suction position with respect to the second-stage rack obtained by this shift calculation, and thereafter, the above-described processing is repeated for all the stages of racks stored in the storage device. That is, while detecting the presence or absence of a substrate for every rack of the storage cassette for each rack, the substrate carrying-out process is performed for each rack in which the substrate is present. By performing such an operation, a substrate detection process only for detecting a substrate is not required, and the substrate detection process and the unloading process are performed simultaneously. Further, it is not necessary to provide sensors necessary for substrate detection in all of the plurality of racks, and only one sensor may be provided in the robot hand.

  By the way, when the transfer robot unloads the substrate in the storage cassette, the hand is slightly smaller than the suction position in order to avoid interference between the hand that has entered the storage cassette and the substrate stored in the rack. First, it moves to the approach position set downward, and then moves from the approach position toward the suction position. Therefore, the work program stored in the storage device also describes the entry position with respect to the board stored in the lowermost rack. As described above, after the carry-out process for a substrate stored in a rack is completed, the transfer robot again follows the work program until the substrate detection / unload process is completed for all racks in the storage cassette. Will work. However, in the work program at this time, the suction position is updated to the position at the time of the previous board unloading by the shift calculation described above, but the entry position is the entry position with respect to the board stored in the lowermost rack. It remains. For this reason, when the carry-out process for the substrates stored in other racks is performed after the carry-out process for the substrates stored in a certain rack is completed, the transfer robot moves to the entry position for the substrates stored in the lowermost rack. It will be. However, since the board is not stored from the bottom rack to the rack in which the board carried last time is stored, it is efficient to move to the entry position with respect to the board stored in the bottom rack again. Is bad.

  Therefore, according to a second aspect of the present invention, in the first aspect of the invention, the arithmetic device performs a shift operation on the entry position of the transfer robot into the storage cassette and the suction position of the substrate. Substrate accommodated in other racks after completion of carry-out processing for substrates accommodated in a rack by performing the shift operation on the adsorption position of the substrate described above also for the entry position of the transport robot into the storage cassette. When carrying out the unloading process, the transfer robot moves to the shifted entry position, that is, the entry position for the substrate stored in the rack one level higher than the rack in which the previously unloaded substrate is stored. Therefore, the operation efficiency is improved.

  According to the present invention, since the substrate detection process for detecting the substrate is not required and the substrate detection process and the unloading process are performed at the same time, the tact time is shortened. Further, it is not necessary to provide sensors necessary for substrate detection in all of the plurality of racks, and only one sensor needs to be provided in the robot hand, so that the cost is reduced.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing the structure of a storage cassette 1 in which a plurality of thin substrates 3 can be stored. FIG. 2 is a block diagram showing a substrate transfer robot system according to this embodiment including a transfer robot 4 for transferring a substrate 3 and its control device 7.

  As shown in FIG. 1, the storage cassette 1 is a box-shaped container for storing a large number of substrates 3 stacked one above the other, and a plurality of shelf-like grooves are cut on the inner wall thereof. By inserting one thin substrate 3 such as a liquid crystal or a wafer into each rack 2 to be formed, the vertically stacked substrates 3 are not in contact with each other. The plurality of racks 2 are arranged at equal intervals. As shown in FIG. 2, the transfer robot 4 is a robot having a multi-joint structure, and is equipped with a hand 5 for transferring the substrate 3 at the tip of the arm. The hand 5 has a structure capable of attracting the substrate 3 from below the substrate 3. The hand 5 is equipped with a sensor 6 for detecting the presence or absence of the substrate 3 in the rack 3. The sensor 6 includes a reflective laser sensor and a detection circuit unit provided in a sensor case. By projecting the reflection type laser sensor toward the upper side of the hand 5, the substrate 3 existing above the hand 5 can be detected. In addition, by adjusting the detection circuit unit described above, the sensor 6 can detect only the substrate 3 existing in the rack 2 immediately above the hand 5.

  The robot 4 operates according to a work program stored in the storage device 8 in the control device 7 that controls the robot 4. In this work program, a series of work steps for detecting and carrying out the substrate 3 stored in the storage cassette 1 is described. However, this work program does not describe the substrate detection / unloading process for all the racks 2 of the storage cassette 1, but includes the substrate detection / unloading process for only the bottom rack 2 of the storage cassette 1. is described. This work program is created by teaching (teaching) the robot 4 in advance. At the time of such teaching, the storage device 8 stores an approach position and a suction position described later as a teaching position.

  Further, in the storage device 8, as information on the storage cassette 1, information on the interval between the racks 2, that is, the height of one stage of the rack 2 and the total number of stages of the rack 2 (hereinafter referred to as “information on the rack”) is stored in advance. It is remembered. Information on the rack is used in the substrate detection / transport process. That is, the movement of the hand 5 between the racks 2 is performed by the arithmetic device 9 in the control device 7 shifting the teaching position (the approach position and the suction position) described above based on the information on the rack described above. For example, as described above, at the time of teaching the robot 4, only the entry position and the suction position for the lowermost rack 2 of the storage cassette 1 are taught, but the entry position and the suction position for the other racks 2 are taught. Based on the approach position and the suction position related to the lowermost rack 2 and the information related to the rack described above, the calculation device 9 performs a shift operation to calculate.

  Next, a substrate carry-out method according to the present embodiment will be described. FIG. 3 is a flowchart showing the flow of the substrate carry-out process executed in the substrate transfer robot system according to this embodiment. In the following description, step numbers in parentheses correspond to symbols (several orders) indicating steps in the flowchart of FIG.

  First, the robot 4 enters the lowest rack 2 of the storage cassette 1 based on the above-described work program stored in the storage device 8, and moves to the taught entry position (step 10). Here, the entry position is a position set between the position of the lowermost rack 2 and the position of the bottom surface of the housing of the storage cassette 1, and the substrate 3 is temporarily stored in the lowermost rack 2. Even in this case, the hand 5 that has entered the rack 2 does not interfere with the substrate 3 and the bottom surface of the housing of the storage cassette 1.

  Next, the sensor 6 is set in a monitoring state, so that the presence or absence of the substrate 3 in the rack 2 can be detected by the sensor 6 (step 11). This is because the sensor 6 is provided to detect the substrate 3 in the storage cassette 1, so that the robot 4 can be prevented from malfunctioning due to a false detection when the hand 5 has not entered the storage cassette 1. This is because the sensor 6 is kept in the monitoring state only when the hand 5 is in the storage cassette 1.

  Next, the robot 4 starts moving from the approach position to the suction position taught in advance based on the above-described work program stored in the storage device 8 (step 12). Here, the suction position is a position where the hand 5 can suck the substrate 3 and is set above the entry position. The initial suction position is a position where the hand 5 can suck the substrate 3 when the substrate 3 is stored in the lowermost rack 2, and this position is given in advance as described above.

  In the process of moving the robot 4 to the suction position in step 12, if there is an input to the sensor 6 in the monitoring state (step 13Y), it is determined that the substrate 3 is stored in the lowermost rack 2.

  If it is determined in step 13 that the substrate 3 is stored in the lowermost rack 2, when the robot 4 completes the movement to the suction position, the hand 5 sucks the substrate 3 and the robot 4 As a result of the operation, the substrate 3 is unloaded (step 14).

  On the other hand, in the process of moving the robot 4 to the suction position in step 12, if there is no input to the sensor 6 in the monitoring state (step 13N), the arithmetic unit 9 sets the entry position and suction position at the initial position, that is, at the time of teaching. The position is shifted upward from the position by the height of the rack 2 (step 15). As described above, since the storage device 8 stores in advance the height of one step of the rack 2 as information about the rack, the height of one step of the rack 2 is set above the entry position and the suction position. That is the amount of shift. This shift amount is sent from the storage device 8 to the arithmetic device 9, and a new approach position and suction position shifted in the arithmetic device 9 are calculated.

  When the new suction position shifted in step 15 is calculated, the process returns to step 12 again, and the robot 4 continues to move toward the shifted new suction position. Thereafter, the processes of steps 12, 13, and 15 are looped until the input of the sensor 6 is detected in step 13 described above, that is, until the rack 2 containing the board 3 is confirmed.

  When the operation of sucking and unloading the substrate 3 in step 14 described above is completed, the storage device 8 stores the number of steps of the rack when the substrate 3 is sucked at this time (step 16). Here, the number of rack stages is defined as the lowest rack 2 being the first stage, and the rack 2 above the second rack being the second, third,... In order from the bottom. The number of racks may be calculated, for example, by counting the number of shifts of the entry position and the suction position in step 15 described above.

  Next, it is determined whether or not the hand 5 has moved to the uppermost stage of the rack 2 (step 17). As a determination method, the number of rack stages stored in the storage device 8 in step 16 described above is compared with the total number of racks 2 stored in advance in the storage apparatus 8. Here, if the number of racks stored in the storage device 8 in step 16 is equal to the total number of racks 2 previously stored in the storage device 8, the hand 5 has moved to the uppermost stage of the rack 2. Judgment is made (step 17Y), that is, it is judged that all the substrates 3 existing in the storage cassette 1 have been unloaded, and a series of processing is terminated (END). On the other hand, if the number of racks stored in the storage device 8 in step 16 is less than the total number of racks 2 stored in advance in the storage device 8, the hand 5 has not moved to the uppermost stage of the rack 2. Judgment is made (step 17N).

  Next, if it is determined in step 17 described above that the hand 5 has not moved to the uppermost stage of the rack 2, the entry position and suction position at that time are stored in the storage device 8 in step 16 described above. The rack 2 is shifted upward by the height of one stage (step 18). The processing in step 18 is performed in order to efficiently perform the next substrate carry-out processing. The detailed reason is as follows. That is, after the substrate unloading process is performed in step 14 described above, if it is determined in step 17 described above that the hand 5 is not in the uppermost rack position, the process in step 10 and subsequent steps, that is, in the storage cassette 1 is performed again. The remaining substrate 3 is unloaded. However, if the hand 5 enters again from the lowermost stage of the rack 2, the processing from the lowermost rack 2 where the substrate 3 is not clearly present to the rack 2 where the board 3 was previously unloaded is performed again. ineffective. Therefore, by performing the process in step 18, in the next substrate carry-out process after step 10, the process is performed from the rack 2 that is one level higher than the rack 2 that carried the substrate 3 last time. Therefore, the processing from the lowest rack 2 where the substrate 3 is not clearly present to the rack 2 where the substrate 3 was previously unloaded is not performed again, and the time required for the next substrate unloading process can be shortened.

  The embodiment of the present invention has been described above. In this embodiment, when the robot 4 enters the storage cassette 1 in order to carry out the substrate 3, the robot 4 first enters the rack 2 at the lowest level and moves upward to suck the substrate 3 therefrom. At this time, the sensor 6 attached to the hand 5 of the robot 4 detects the presence or absence of the substrate 3 in each rack 2 while the robot 4 moves upward, and if there is a substrate 3 in the rack 2, sucks it. On the other hand, if there is no substrate 3 in the rack 2, the robot 4 continues to move toward the upper rack 2 until the substrate 3 is detected. By performing such an operation, the substrate detection process only for detecting the substrate 3 is not required, and the detection process and the unloading process of the substrate 3 are performed at the same time, so that the tact time is shortened. Further, it is not necessary to provide the sensors 6 necessary for detecting the substrate 3 in all of the plurality of racks 2, and only one sensor 6 needs to be provided in the hand 5 of the robot 4, so that the cost is reduced.

  In the present invention, it is assumed that the work program describes the unloading process for the substrate 3 stored in the lowermost rack 2 of the storage cassette 1, but this is stored in an arbitrary rack 2 of the storage cassette 1. It can be easily developed that the carry-out process for the substrate 3 is described. However, when the substrate 3 is highly brittle such as a liquid crystal or a wafer, the hand 5 is often structured to adsorb the substrate 3 from below, and in this case, the hand 5 is the top of the storage cassette 1. It is most efficient to enter from the lower rack 2. Therefore, in this case, it is most efficient to describe the carry-out process for the substrate 3 stored in the lowermost rack 2 of the storage cassette 1 in the work program.

It is explanatory drawing which shows the structure of the storage cassette 1 in which the several thin board | substrate 3 was storable. 1 is a configuration diagram showing a substrate transfer robot system according to the present invention including a transfer robot 4 for transferring a substrate 3 and a control device 7 therefor. It is the flowchart shown about the flow of the board | substrate carrying-out process performed in the robot system for board | substrate conveyance which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage cassette 2 Rack 3 Board | substrate 4 Robot 5 Hand 6 Sensor 7 Control apparatus 8 Memory | storage device 9 Arithmetic unit

Claims (2)

In a robot system for transporting a substrate that unloads a substrate stored in a storage cassette having a plurality of racks for enabling storage of a plurality of substrates from the storage cassette,
The substrate transfer robot system includes a transfer robot for unloading a substrate stored in a storage cassette from the storage cassette, and a control device for controlling the transfer robot.
The transfer robot is equipped with a hand capable of gripping a substrate at the tip of the arm,
The hand includes a sensor capable of detecting the presence or absence of a substrate in the rack,
The control device includes:
A storage device that stores a work program in which an unloading process for a substrate stored in the bottom rack of the storage cassette is described, the height of one rack, and the total number of racks;
An arithmetic unit that performs a shift operation on the suction position of the substrate;
A robot system for transporting a substrate, comprising:   2. The substrate transfer robot system according to claim 1, wherein the calculation device performs a shift calculation with respect to an entry position of the transfer robot into the storage cassette and a suction position of the substrate.

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