JP2007188336A - Process control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve improvement of throughput of a whole manufacturing line and shortening lead time by reduction of works in process when processing equipment capable of processing a work of a plurality of processes selects the work to be processed next out of works of a plurality of processes. <P>SOLUTION: A process control unit is equipped with; a process management means 107 which collects and stores information on work in process from a real line; a calculation storage means 102 to calculate processing priority for each process from information on work in process for each process stored in the above process management means 107 and the number of works in process required for each process set up beforehand; a work selection means 103 which selects work to be processed next based on processing priority stored in the above calculation storage means 102; and a work instruction means 104 to give a work instruction to the work selected in the above work selection means 103. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a process control apparatus, and in particular, in a manufacturing line having a processing facility capable of processing a workpiece in a plurality of processes, such as a semiconductor manufacturing line, a plurality of processing facilities usable in a plurality of processes. A process control device that determines a workpiece to be processed next from the in-process when process in-process is accumulated.

  In semiconductor manufacturing, in general, a series of patterning processes (called one cycle) of film formation process → photolithographic process (resist pattern formation) → etching process (resist pattern transfer) → resist stripping process → inspection process. By processing the workpiece, one pattern is formed on the workpiece. By repeating this cycle and forming a plurality of patterns, a semiconductor circuit is completed.

  In semiconductor manufacturing, processing equipment that performs processing in each process frequently stops processing equipment due to trouble or maintenance. Also, once stopped, the period of stoppage is long, so it is necessary to secure an in-process in each process in order to operate other processing equipment.

  For example, when there is no work in the photolithography process, if the processing equipment in the film forming process stops due to a trouble, there is no work to be supplied to the photolithography process. For this reason, there is no work to be processed by the apparatus that executes the photolithography process, and the operating rate of the processing equipment that executes the photolithography process is lowered. As a result, the production capacity of the production line is reduced. In this case, if you have a sufficient number of in-process devices to supply to the photolithographic process, even if the processing equipment for the film-forming process stops, the photolithographic process selects the workpiece from the in-process and processes it. It can continue and the utilization rate of the processing equipment will not decrease.

  In general, a dispatch rule is used as a rule for selecting a work to be processed from the plurality of devices. As this dispatch rule, for example, (a) a workpiece with the shortest machining time is selected, (b) a workpiece with the shortest period until delivery date is selected, and (c) a scheduled production completion time from the average passing time of the remaining processes (D) select a work that needs to be processed with the highest priority, (e) select a work that has entered the in-process state first, (f) stage There are rules such as selecting the work with the minimum replacement time, and the rules suitable for the factory are used.

As another work selection method, for example, in Patent Document 1, the processing start order of the previous process is determined based on the result of comparing the current work-in-process amount in the subsequent process with a predetermined reference value. In addition, Patent Document 2 describes a method for preferentially processing a work that can be processed up to the next two steps.
JP-A-1-183347 JP-A-10-277891

  However, the throughput of the production line may decrease with the conventional dispatch rule alone. That is, each of the above methods (a) to (f) is a lot selection method that does not consider the number of in-process work in each step. For example, if there is a large amount of work in progress in the next process, the need for processing is low. Conversely, if there is no work in the next process, it is predicted that the need for processing is high. If a lot is selected without considering the number of waiting points, a standby loss is likely to occur in the processing equipment in the subsequent process, which causes a decrease in the throughput of the production line.

  On the other hand, the techniques described in Patent Documents 1 and 2 are means for avoiding the above-described problem, and aim to reduce the standby loss of the processing equipment in the next process or the next two processes. This alone does not necessarily increase the throughput of the production line. For example, even when there is little work in progress in the next process or in the next two processes, if a large amount of work is accumulated in the processing equipment in the third process, the priority of processing may be low. Conversely, even if there is a problem in the next process due to trouble occurring in the next process, there is a certain degree of work in preparation for the case where the current process is stopped due to trouble. In some cases, it may be necessary to store this in the next process.

  The present invention was devised to solve such problems, and its purpose is to grasp the in-process status of each process of each production line and calculate the processing priority of each process, thereby reducing the equipment loss. It is an object of the present invention to provide a process control apparatus that reduces and improves the throughput of a production line.

  In order to solve the above problems, the process control apparatus of the present invention is applied to a production line having a processing facility capable of processing a workpiece in a plurality of processes, and collects and stores in-process information from the actual line. Process management means, and a calculation storage for calculating and storing processing priority for each process from the number of work in progress for each process stored in the process management means and the number of work in progress required for each process set in advance Means, a work selection means for selecting a work to be processed next using the processing priority stored in the arithmetic storage means, and a work instruction for giving a work instruction to the work selected by the work selection means Means.

  According to the present invention having such features, the number of in-processes is collected for each process, and the number of in-processes for each process collected and the number of in-process necessary for each process set in advance, Therefore, the apparatus loss can be reduced, and the throughput of the production line can be improved.

  Further, according to the process control apparatus of the present invention, the calculation storage means includes the number of work in progress of each process stored in the process management means, the number of work in progress required in each process set in advance, The processing priority for each work can be calculated and stored from the evaluation value for evaluating the close time. The evaluation value can be, for example, in order of oldest time. As described above, when the processing is performed in order from the oldest time, for example, in the case of the cleaning process and the subsequent film process, the yield of the product is improved when the processing is performed continuously, this evaluation value is used. It is good.

  Further, according to the process control device of the present invention, the calculation storage means includes the number of work in progress for each process stored in the process management means, the number of work in progress necessary for each process set in advance, and processing The processing priority for each workpiece can be calculated and stored from the evaluation value for evaluating the proximity of the workpiece obtained from the equipment and workpiece position information. For example, if there are multiple processing facilities of the same type and each facility is installed at a remote location, the work in progress for that process is usually distributed in a place where each processing facility is located. ing. In such a case, it is possible to reduce standby loss due to waiting for conveyance between processes by preferentially processing workpieces that are close to each processing facility.

  Further, according to the process control apparatus of the present invention, the calculation storage means includes the number of work in progress for each process stored in the process management means, the number of work in progress necessary for each process set in advance, The processing priority for each workpiece can be calculated and stored from the evaluation value for evaluating the margin for the delivery date of the workpiece obtained from the progress and delivery date information. According to such a configuration, it is possible to preferentially process a workpiece that has been delayed in progress. For example, it is determined that the workpiece is inferior in a workpiece that has been delayed in progress due to processing equipment being stopped during the processing or an inspection facility. It is possible to preferentially process a work that has been delayed due to rework processing or a work that has a rapid delivery date.

  Further, according to the process control device of the present invention, the calculation storage means includes the number of work in progress for each process stored in the process management means, the number of work in progress necessary for each process set in advance, and processing The processing priority for each workpiece can be calculated and stored from the evaluation value for evaluating the equipment setup change time. According to such a configuration, when the setup change time occurs because the model is different even in the same process, the workpiece of the same model can be continuously processed.

  Since the process control device of the present invention is configured as described above, when multiple processes can be processed with the same equipment, the processing priority of each process is calculated from the in-process status of each process on the production line. However, by giving priority to the process with the higher processing priority, the apparatus loss can be reduced and the throughput of the production line can be improved. In addition, according to the present invention, as a result, a work that is relatively free from the next process is selected, and the residence time of the work is reduced and the production lead time is shortened. The number can be reduced. Furthermore, according to the present invention, when the priority of the top process becomes positive (1 or higher), if the input to the top process is performed, the number of devices in the production line can be controlled to be constant. In addition, since the lead time can be controlled to be constant, it is possible to prevent an unnecessary increase in work due to excessive charging and to prevent the lead time from being prolonged.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a functional block diagram showing a configuration of a process control apparatus according to an embodiment of the present invention.

  In FIG. 1, a production line 109 is a form of a production line for processing products, and a total of eight processing facilities 108 are installed. Among these, the processing equipment B and the processing equipment D are processing equipment that can be processed in a plurality of processes, and the other processing equipments A, C, and E are processing equipment that can process only a specific process.

  The process control apparatus 101 that controls the process of the manufacturing line 109 having the above-described configuration includes an operation storage unit 102, a work selection unit 103, a work instruction unit 104, and a process management unit 107.

  The process management means 107 plays a role of collecting and managing information from the production line 109 and grasps the progress of all workpieces in the production line 109 and the operation status of the equipment. Therefore, if the data in the process management means 107 is aggregated, the number of work in progress for each process can be obtained, and the position of each workpiece can also be obtained.

  Further, upon receiving a work request from the processing equipment 108, the process management means 107 outputs a work selection request R2 to the work selection means 103. Furthermore, the process management unit 107 provides the number of in-process items for each process as the in-process information R1 to the calculation storage unit 102. In addition, the position of each work, progress, delivery date, processing equipment position information, etc. are provided as necessary.

  Upon receiving the work selection request R2 from the process management means 107, the work selection means 103 causes the arithmetic storage means 102 to calculate the work processing priority, selects a work with a high processing priority, A work instruction for the selected workpiece is output to 104.

  When the work selection unit 103 instructs the calculation storage unit 102 to calculate the processing priority, the calculation storage unit 102 requests the in-process information R1 from the process management unit 107 and reads out the in-process information R1 in advance. The processing priority of each process is calculated from the number of in-process necessary processes. At this time, when there are a plurality of workpieces in a process with a high processing priority, it is necessary to further determine the priority for each workpiece. Therefore, position information for each workpiece and in-process are obtained from the process management means 107. The processing time, the position information of the work and the processing equipment, the work progress and the delivery date information are read out, the processing priority for each work is calculated, and the information is given to the work selection means 103.

  Next, lot selection performed by the process control apparatus 101 of the present embodiment will be described.

  FIG. 2 is an explanatory diagram showing the relationship between the process managed by the process management means 107 of this embodiment and the processing apparatus. Here, a semiconductor manufacturing process is illustrated.

  In FIG. 2, the manufacturing process includes a first cycle and a second cycle, and the second cycle is performed after the first cycle. The first cycle includes a step 1 for film formation at the processing facility A1, a step 2 for photolithography processing at the processing facility B, a step 3 for etching at the processing facility C1, and a step 4 for stripping the resist at the processing facility D. And the process 5 inspected by the processing equipment E1. The second cycle includes a step 6 for film formation at the processing facility A2, a step 7 for photolithography processing at the processing facility B, a step 8 for etching at the processing facility C2, and a step 9 for stripping the resist at the processing facility D. And the process 10 inspected with the processing equipment E2. In the semiconductor manufacturing process, a cycle including a film forming process, a photolithography process, an etching process, a resist stripping process, and an inspection is repeated many times. Here, in order to simplify the description, the first cycle and the second cycle are performed. Is repeated twice.

  Further, in FIG. 2, X (1) is the work that is in process 1 and X (2) is the work that is in process 2, and the work that is in process 3 is in progress. X (3), work in process 4 is X (4), work in process 5 is X (5), work in process 6 is X ( 6) X (7) for the work in process 7 and X (8) for the work in process 8 and X (9) for the work in process 9 The workpiece that is the in-process of step 10 is represented by X (10).

  The processing facility B can process both the in-process workpiece X (2) in the process 2 and the in-process workpiece X (7) in the process 7, and the processing facility D also processes the in-process workpiece X in the process 4. Both the workpiece X (4) and the in-process workpiece X (9) in step 9 can be processed. Here, there may be a plurality of processing facilities A1 that can be processed in the step 1, or a plurality of processing facilities B that can process both the steps 2 and 7.

  In the case of FIG. 2, since the processing equipment A1 can only process X (1), a lot is selected from X (1) and processing is performed by the processing equipment A1. As a rule for selecting a lot, there is a method described in the prior art, but basically, any work in progress in X (1) does not affect the subsequent process. However, if multiple models are introduced to the production line and the tact time differs for each model, or if a model change time occurs when a lot of a different model is selected, the processing equipment in that process or the subsequent process It may affect the operation rate of other processing equipment. The processing facilities A2, C1, C2, E1, and E2 are the same as the processing facility A1.

  On the other hand, the processing equipment B has two types of work-in-process workpieces X (2) and X (7) that can be processed. Affects equipment throughput. For example, in a situation where there is a large amount of X (3) work in progress and no X (8) work in progress, the X (7) work in process is basically prioritized over X (2). It is considered that the loss of the processing equipment C2 is small. Similarly, the processing equipment D has two types of work in progress, X (4) and X (9), and it is necessary to select one of the lots.

  In this way, in the processing equipment B and processing equipment D that can be used in a plurality of processes, selecting a lot from among the in-process devices can increase the throughput of the processing equipment in the subsequent process, and consequently the throughput of the entire production line. Appropriate lot selection is required to have an impact.

  Next, the operation of the process control apparatus 101 according to the present embodiment will be described with reference to the flowcharts of FIGS. 3, 4, and 5. However, FIG. 3 is a flowchart for explaining the operation of the process management means in the present embodiment, FIG. 4 is a flowchart for explaining the operation of the work selection means in the present embodiment, and FIG. 5 is the present embodiment. It is a flowchart explaining the operation | movement of the arithmetic storage means in.

  First, in step S01, the process management unit 107 monitors a work request from the processing apparatus 108. If there is a work request from the processing apparatus 108, the process management unit 107 proceeds to step S02. In step S02, a workpiece selection request R2 for selecting the workpiece to be processed next by the machining apparatus 108 is issued to the workpiece selecting means 103, and the process proceeds to step S03. In step S03, it waits for the workpiece selecting means 103 to select a workpiece.

  In step S11, the work selection means 103 monitors the work selection request R2 from step S02 of the process management means 107. If there is a work selection request R2, the process goes to step S12. In step S12, the calculation storage unit 102 is instructed to calculate the processing priority of the work, and the process proceeds to step S13. In step S13, the process waits until the calculation storage unit 102 calculates the processing priority of the workpiece.

  In step S21, the calculation storage means 102 sets the required number of devices in progress for each process in advance, and proceeds to step S22. In step S22, if there is an instruction from the workpiece selecting means 103 (instruction in step S12), the process proceeds to step S23. In step S23, in-process information is acquired from the process management means 107, and the process proceeds to step S24. In step S24, the processing priority of the process to be selected for the lot selection is calculated from the required number of work in progress for each process set in step S21 and the work in progress information acquired in step S23, and the process proceeds to step S25. In step S25, the priority of each process obtained in step S24, the evaluation value for evaluating the time when the work is finished, and the proximity of the work obtained from the processing equipment and the position information of the work are evaluated. The processing priority is calculated for each workpiece based on the evaluation value, the evaluation value that evaluates the margin for the workpiece delivery date obtained from the workpiece progress and delivery date information, and the evaluation value that evaluates the changeover time of the processing equipment. The process proceeds to step S26. In step S26, the work selection means 103 is notified that the process is completed, and the process returns to step S22.

  In step S13, the work selection unit 103 monitors the completion of the calculation process in the calculation storage unit 102. When it is confirmed that the calculation process has been completed, the work selection unit 103 proceeds to step S14. In step S14, the work having the highest processing priority is selected, and the process proceeds to step S15. In step S15, the work selection result is transmitted to the process management means 107.

  If the process management means 107 confirms in step S03 that the work selection means 103 has completed selection of a work, the process management means 107 proceeds to step S04. In step S04, the workpiece selected by the workpiece selecting means 103 is instructed to be conveyed to the processing facility, and when the workpiece arrives at the processing facility, the processing facility is instructed to perform a machining operation.

  Next, a method for calculating the processing priority of each process will be described with reference to FIG.

  FIG. 6 is an explanatory diagram illustrating an example of a table stored in the operation storage unit 102 according to the present embodiment. This table summarizes the number of in-process items, the required number of in-process items, and the processing priority for each step from step 1 to step 10.

  The in-process number (X) is obtained by substituting the in-process information R1 read from the process management means 107 into a table. In the present embodiment, in FIG. 2, it is assumed that a trouble occurs in the processing equipment of the processing equipment E1 and stops, and the number of devices in process 5 has increased to 13.

  The required number of work in progress (Y) is the number of work in progress for each process that is preset and stored in the operation storage means 102, and even if the number of ports of the processing equipment (number of workpieces can be placed) is set. It is good to set the number of in-process work for the time to stop in preparation for the processing equipment of each process to stop due to trouble or maintenance, or to increase the operating rate of the rate-limiting process with the lowest capacity A large number of in-process necessary steps before and after the rate-limiting step may be set. Here, in order to simplify the description, “4” is set for each process, assuming that each process requires four workpieces. The processing priority (Z) at this time can be obtained by a calculation formula such as the following formula (1).

Z (i-1) = Z (i) + Y (i) -X (i) (Formula 1)
According to this calculation formula, the processing priority Z (10) of step 10 cannot be calculated.
Z (10) = 0
And

Next, the processing priority Z (9) of step 9 is
Z (9) = Z (10) + Y (10) -X (10) = 1
It becomes. Process 10 shows that the number of work in progress is only 3 and that there is only 3 work in progress, so another work is required, and process 9 indicates that one work needs to be processed. Yes.

Similarly, the processing priority Z (8) in step 8 is
Z (8) = Z (9) + Y (9) -X (9) = 2
It becomes. Since the number of in-process is only 3 for the required number of in-process 4, the number of in-process is only 3, and another work is required. Shows that it is necessary to process a total of two workpieces.

  Thus, this table is completed by calculating | requiring process priority (Z) in an order from a back process.

According to this table, for processing equipment B, the processing priority of step 2 and step 7 is
Z (2) = 2
Z (7) = 3
Since the processing priority of the process 7 is higher, the next lot to be processed is selected from the work in progress of the process 7.

  The processing facility B can process two steps, step 2 and step 7. Here, step 7 is selected even though there are more work pieces in process 8 and step 9 which are subsequent steps of step 7 than steps 3 and 4 which are subsequent steps of step 2. This is because it is judged that the necessity of proceeding with the process 2 is low because 13 work pieces are accumulated in the process 5.

  However, if the processing capacity of the process 3 is low and it is necessary to reduce the loss of the processing device C1 as much as possible, it is better to proceed to the process 3 even if there is a lot of work in progress in the process 5. There is a case.

For example, as shown in the table of FIG. 7, if the required number of work in process 3 is set to be larger than the other processes (12 in this example), the entire work in progress so as to accumulate work in process 3. Is controlled. According to the table of FIG. 7, when the same calculation formula 1 as described above is used, even if the number of devices in process is the same as in FIG.
Z (2) = 3
Z (7) = 0
Since the processing priority of the process 2 is higher, the work of the process 2 is selected and the work in process 3 is secured.

  As shown in FIG. 7, the number of work in progress for the entire production line is set by setting the required number of work in consideration of the processing capacity of the processing equipment, or by setting the value in preparation for equipment stoppage such as trouble or maintenance. The most suitable lot can be selected from the situation.

  Depending on the processing priority for each process determined above, the process to be processed next can be determined, but if there are multiple work in progress for that process, which work should be prioritized It is necessary to decide.

  Therefore, as this determination method, it is possible to use a method (processing 1) in which processing is performed in order from the oldest time when the work is in process. For example, there may be a case where the yield of the product is improved by performing the treatment continuously like the cleaning step and the film forming step performed before the film formation. In such a case, this method may be used.

  Further, as the determination method described above, a processing method (processing 2) in which processing equipment and position information of a workpiece are acquired from the process management unit 107 and processing is performed with priority on a workpiece having a short distance. For example, if there are multiple processing facilities of the same type and these facilities are installed at remote locations, the work in progress for that process is usually distributed and distributed at the locations where each processing facility is located. It is burned. Accordingly, each processing facility can reduce standby loss due to waiting for conveyance if the nearby work is preferentially processed.

  In addition, as the determination method described above, it is possible to use a method (processing 3) for determining the processing priority of a workpiece from an evaluation value for evaluating a margin with respect to the workpiece delivery date obtained from the work progress and delivery date information. With such a method, it is possible to preferentially process a work whose progress is delayed. For example, it is possible to preferentially process workpieces that have been delayed due to processing equipment being stopped during processing, workpieces that have been judged to be defective by the inspection facility and have been delayed due to rework processing, or workpieces that have a rapid delivery date. it can.

  Further, as the determination method described above, a method of selecting a workpiece (processing 4) in consideration of the setup time of the machining equipment can be used. With this method, workpieces of the same model can be continuously processed when setup change time occurs because the models are different even in the same process.

  Moreover, in this invention, you may use the said process 1-process 4 combining, and may use the process (any one of the said process 1-process 4) different for every process.

  In the present invention, either the processing priority of each process or the processing priority of the work may be given priority, and each work priority is weighted and calculated to select the work. Also good.

  Further, according to the tables of FIG. 6 and FIG. 7, the work may be input to the process 1 when the processing priority is positive (1 or more). The total number of work in progress is controlled to be the sum of the values set in the number of work in progress, and unnecessary work in progress is prevented. Further, by controlling the total number of work in progress on the production line, the production lead time can be controlled to be kept constant.

  The present invention can be used in a manufacturing line having a processing facility capable of processing a workpiece in a plurality of processes, such as a semiconductor manufacturing line and a liquid crystal manufacturing line, as well as a home appliance assembly line. In addition, even a production line that does not use processing equipment in a plurality of processes can be used as an apparatus that optimally controls the number of devices in process.

It is a functional block diagram which shows the structure of the process control apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the relationship between the process managed by the process management means of this Embodiment, and a processing apparatus. It is a flowchart for demonstrating operation | movement of the process management means in this Embodiment. It is a flowchart for demonstrating operation | movement of the workpiece | work selection means in this Embodiment. It is a flowchart for demonstrating operation | movement of the calculation memory | storage means in this Embodiment. It is explanatory drawing which shows an example of the table memorize | stored in the calculation memory | storage means in this Embodiment. It is explanatory drawing which shows an example of the table memorize | stored in the calculation memory | storage means in this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Process control apparatus 102 Operation | movement storage means 103 Work selection means 104 Work instruction means 105 In-process information 106 Work selection request 107 Process management means 108 Processing equipment 109 Production line

Claims (5)

A process control device in a production line having processing equipment capable of processing a workpiece in a plurality of processes,
Process management means for collecting and storing in-process information from the line;
An arithmetic storage means for calculating and storing a processing priority for each process from the in-process number of each process stored in the process management means and a preset in-process required number of each process;
Work selection means for selecting a work to be processed next using the processing priority stored in the arithmetic storage means;
A process control device comprising: work instruction means for giving a work instruction to the work selected by the work selection means.   The calculation storage means is based on the number of in-process work for each process stored in the process management means, the number of work in progress required for each process set in advance, and an evaluation value for evaluating the time at which the process is completed. The process control apparatus according to claim 1, wherein the processing priority for each workpiece is calculated and stored.   The calculation storage means is the number of work in progress for each process stored in the process management means, the number of work in progress required for each process set in advance, and the workpiece information obtained from the processing equipment and the position information of the work. The process control device according to claim 1, wherein a processing priority for each workpiece is calculated and stored from an evaluation value for evaluating proximity.   The calculation storage means includes the number of work in progress for each process stored in the process management means, the number of work in progress necessary for each process set in advance, and the work delivery time determined from the work progress and delivery time information. The process control apparatus according to claim 1, wherein a processing priority for each workpiece is calculated and stored from an evaluation value for evaluating a margin for the workpiece.   The calculation storage means is based on the number of work in progress for each process stored in the process management means, the number of work in progress required for each process set in advance, and an evaluation value for evaluating the setup time of the processing equipment. The process control apparatus according to claim 1, wherein the processing priority for each workpiece is calculated and stored.

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