JP2000236008A - Carriage control method in wafer automatic carriage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent accumulation of cassettes at a current storage container by seeking another container in a process line with a minimum carriage time and storing the cassette temporarily in this container when a container in a following carriage process line has no vacant. SOLUTION: A cassette 6 with a wafer processed in a process line 1a is stored in a storage container 3a and carried to a following process line 1b. If the following process line 1b is not in a state of readiness to receive the cassette 6, the cassette 6 is deposited temporality in a storage container 3c of a process line 1c that is ready to receive the cassette 6 with a minimum carriage time, until the following process line 1a becomes ready to receive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for transferring a cassette containing wafers processed in one manufacturing process to a next manufacturing line when the next manufacturing line to be sent is not in a receiving state. Automatically finds the production line with the shortest transfer time in the production line, temporarily stores the cassette in the stocker until the next production line is in the receiving state, and holds the entire system during transportation. The present invention relates to a transfer control method in an automatic wafer transfer system that prevents the occurrence of an error and improves the operation rate of the apparatus.

[0002]

2. Description of the Related Art In a clean room of a semiconductor factory, a job shop system in which a plurality of processing apparatuses are gathered and arranged in one area for each processing step of the same type is mainly used.
A plurality of production lines are configured, and each production line is provided with a stocker having both a buffer function and a storage function because the processing speed of each processing device is different. And
Semiconductor wafers (hereinafter, simply referred to as wafers) are required to be transported in a complicated manner through transport in each production line (hereinafter, transport in process) and transport between stockers in each production line (hereinafter, transport between processes). Processing is performed.

FIG. 5 is a layout diagram schematically showing the arrangement of devices in a conventional semiconductor manufacturing system, and also shows a transfer path of a cassette containing processed wafers to the next step. In FIG. 5, reference numerals 1a to 1h denote manufacturing lines corresponding to arbitrary first to eighth steps, respectively.
A plurality of processing apparatuses 2a to 2 corresponding to the respective steps (for example, photolithography step, ion implantation step, diffusion step, etc.)
h, stockers 3a to 3h capable of storing a plurality of wafer cassettes before and after processing, in-process transfer paths 4a to 4h, and an in-process transfer vehicle 5. Reference numeral 6 denotes a wafer cassette (hereinafter, simply referred to as a cassette) for storing one lot (for example, 25) wafers (not shown) to be processed.
In the in-process transfer paths 4a to 4h, cassettes 6 accommodating wafers to be processed are taken out of the respective stockers 3a to 3h by a transfer machine (not shown) of the in-process transfer vehicle 5, and the required processing apparatuses 2a to 3h. 2h, the processed wafer-containing cassette 6 is taken out of each of the processing devices 2a to 2h and transported and stored in required stockers 3a to 3h. Reference numeral 7 denotes an inter-process transfer path between the manufacturing lines 1a to 1h. A plurality of inter-process transfer vehicles 8 travel clockwise to transfer necessary cassettes 6 containing processed wafers to stockers in the next process manufacturing line. It is transported to the point. Each stocker 3
A transfer machine (not shown) for exchanging the cassette 6 with the inter-process carrier 8 is installed in a to 3h.

When the cassette 6 containing wafers processed in the production line 1a and stored in the stocker 3a is transferred to the next production line 1b, the cassette 6 is transferred to a transfer machine (not shown) of the stocker 3a. Is transferred to the inter-process transfer vehicle 8 (path L ₄₁ ), and transferred to the transfer point of the stocker 3 b in the next process line (path L ₄₂ ). Then are transferred from the interprocess transport vehicle 8 by transfer machine of the stocker 3b to the stocker 3b the (route L _43), further, the process carrying truck 5 is conveyed through the steps in the conveying path 4b (route L ₄₄ ), And is transferred and set in a predetermined device of the processing device 2b by the transfer device (not shown) (path L ₄₅ ). By carrying out the above transport smoothly,
The cassette 6 transported from the previous process of the production line 1a
It can be carried into the stocker 3a of the vacant production line 1a at any time, and the entire transport system can be smoothly transported.

FIG. 6 is a block diagram showing a configuration of a control system of a conventional automatic wafer transfer system. As shown,
The processing devices 2a to 2h, the stockers 3a to 3h, and the in-process transport vehicle 5 of each of the manufacturing lines 1a to 1h are controlled by the in-process device controllers 14a to 14h. Control computer 13
a to 13h. Further, the inter-process carrier 8 is controlled by the inter-process carrier controller 16 and further controlled by the inter-process carrier control computer 15. Then, the in-process transfer control computer 13
The computers a to 13h and the inter-process transfer control computer 15 are controlled by the transfer control computer 12, and the whole is controlled by the system control computer 11. Here, the system control computer 11 stores the lot information of the wafers for each production line and the entire processing flow and performs progress management, and the transfer control computer 12 controls the production line 1 based on the instruction of the system control computer 11.
a to 1h, and the stockers 3a to 3h
h, and stores information such as the vacancy status, failure, and work-in-progress of the intra-process transport vehicle 5, and sends specific transport instructions for the cassette 6 to the intra-process transport control computers 13 a to 13 h and the inter-process transport control computer 15. Advance the progress within and between processes. The in-process transfer control computers 13a to 13h send information such as the vacancy status, failure, and work-in-process in each of the manufacturing lines 1a to 1h to the transfer control computer 12,
In response to the instruction, an in-process transfer instruction is sent to the in-process device controllers 14a to 14h to perform required transfer. Similarly,
The inter-process transfer control computer 15 includes
The transfer information during the time h is sent to the transfer control computer 12, and in response to the instruction, an inter-process transfer instruction is sent to the inter-process transfer device controller 16 to perform required transfer.

FIG. 7 is a flowchart showing a conventional computer-to-manufacture line transfer control. As shown in the drawing, first, when the processing of a wafer is completed in the manufacturing line 1a (S1), the information is transferred from the intra-process transfer control computer 13a via the transfer control computer 12 to the system control computer 1 storing the process of the entire system.
Sent to 1. Then, an instruction to proceed to the next process is sent from the system control computer 11 to the transport control computer 1.
2 and the transport control computer 1 based on the instruction.
2 sends a transfer instruction to the production line 1b in the next process to the in-process transfer control computer 13a. The in-process transfer control computer 13a receiving this instruction sends a required transfer instruction to the in-process device controller 14a. As a result, the wafer-containing cassette 6 is moved by the in-process transfer vehicle 5 to the stocker 3.
a (S2) and stored in the stocker 3a (S3). Then, the transport control computer 12 checks whether there is an empty space in the stocker 3b of the next process manufacturing line 1b. If there is no empty space, the cassette 6 waits in the stocker 3a.
The cassette 6 is transported to the transfer point to the stocker 3b (S5), and stored in the stocker 3b (S5).
6). Next, the cassette 6 is transported and set by the in-process transport vehicle 5 to the next process apparatus 2b (S7), and the transport between the lines is completed.

However, in the automatic wafer transfer system as described above, when the processing unit 2b, the in-process transfer vehicle 5 or the stocker 3b of the production line 1b in the next process is out of order or the stocker 3b is full. In this case, the cassette 6 waiting in the stocker 3a cannot be transported to the stocker 3b. For this reason, the stocker 3a of the own process becomes full during standby until the stocker 3b is in a state where it can be received, and it becomes impossible to carry the stocker 3a of the manufacturing line 1a of the own process to the stocker 3a of the own process. .
That is, there is a problem that the cassette in the previous process to be processed in the production line 1a is not put into the apparatus 2a, and the operation rate of the apparatus 2a is reduced.

In order to solve such a problem, when a processed wafer is transported to the next step, for example, a computer for controlling the transport is required to determine the number of empty processing units in each production line and the number of empty state processing apparatuses. The number of pre-device processing buffers and the number of empty line pre-processing buffers are calculated and stored for each manufacturing line, and the number of cassettes with wafers already determined in the transfer destination line is calculated for each manufacturing line. Remember. Then, from among a plurality of production lines that can be set as transfer destination lines in accordance with the calculation results using the stored numerical values and the process progress, the cassette with wafers already determined for the transfer destination line is selected. Even after all the conveyance is completed, the transfer destination line is determined in the order of a production line having an empty processing device, a production line having an empty buffer before the device processing, and a production line having an empty buffer before the line processing. Therefore, even if the processing capacity differs for each manufacturing line, the balance of the number of cassettes before processing in each line is maintained, and the TAT (Turn Around Ti
Japanese Patent Laid-Open Publication No. 1-30 / 1990
No. 3736.

[0009]

However, in the transfer control method of the prior art, the production line to which the cassette containing wafers is transferred is operated by a plurality of processing units arranged in the production line, Since the determination is made only in accordance with the empty state of the pre-buffer and the pre-line processing buffer, there is a problem that the determined production line at the transfer destination is not necessarily the production line at the position that minimizes the transport time. is there. In addition, when all of the destinations are full, the cassette is not transported anywhere, which causes a problem in that the source stocker is full and the operation rate of the apparatus processing is reduced.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the transfer control method in the conventional automatic wafer transfer system described above, and a cassette containing wafers processed in one process is manufactured in a next production line. If the stocker of the destination production line is not empty when transferring to the destination production line, the stocker of the other production line with the shortest transport time is automatically found and placed in the destination production line. Until the cassette becomes empty, the cassette is temporarily stored and stored to prevent stagnation in the transfer source stocker during cassette transfer, and transfer in the automatic wafer transfer system that improves the operation rate of the entire system. A control method is provided.

[0011]

According to the present invention, there are provided a plurality of processing apparatuses for performing required processing of a wafer, a stocker for temporarily storing a cassette containing wafers before and after the processing, and a processing apparatus for storing a cassette containing wafers before and after the processing. At least one production line corresponding to each of a plurality of production steps, and a stocker for each of the production lines. An inter-process transport path, which is provided in connection with each other and serves as a path through which the cassette is transported between the stockers in accordance with the progress of the process, is used to transport the cassettes in the intra-process transport path and the inter-process transport path by a transport vehicle. In the transfer control method in the automatic wafer transfer system automatically controlled by a computer, the control by the computer is performed when a predetermined processed wafer is loaded. The first step of recognizing that the production line, which is the scheduled transfer destination of the next process of the cassette, is not in the receiving state and searching for a stocker of another manufacturing line on which the cassette can be temporarily placed, other than the next process found by searching A second step of storing a production line in an acceptable state among the production lines, and finding a production line in which the transfer time from the stocker of the processed production line is the shortest among the stored production lines. The third step of storing the cassette in the stocker of the production line where the transport time obtained is the shortest until the next production line is in the receiving state. Further, the inter-process transport path includes first and second inter-process transport paths having mutually opposite orbits connecting the stockers, and the transport time obtained in the second step is the shortest. The production line is obtained based on the transport time when the wafer is transported by the first and second inter-process transport paths.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an inter-process transfer method in a semiconductor manufacturing system according to a first embodiment of the present invention. In each of the drawings, the same reference numerals as those in the prior art indicate the same or equivalent components. same as below. The arrangement of the equipment in FIG. 1 is the same as that in the prior art (FIG. 5), and when the cassette 6 with processed wafers in an arbitrary production line is to be transported to the next production line, the destination production line is The method is characterized in that the cassette 6 is transported when it is not in the receiving state.

Now, the stocker 3 processed in the manufacturing line 1a
In order to convey the cassette 6 containing wafers stored in the stocker 3a to the next production line 1b, there is no empty space in the stocker 3b of the production line 1b,
If there is a failure and is not in the receiving state, another manufacturing line in the receiving state is searched, and the transport time is the shortest among them, for example, when the manufacturing line 1c is obtained,
Cassette 6 is transferred to the interprocess transport vehicle 8 by stocker 3a transfer device (not shown) (path L _11), until the stocker 3c transfer point of interprocess transport path 7 on the production line 1c (route L ₁₂ ) Conveyed. Then it is transferred from the interprocess transport wheel 8 to the stocker 3c in the transfer machine of the stocker 3c (route L ₁₄₎ is temporarily stored. Then, when the stocker 3b of the next process production line 1b is in a receivable state, the cassette 6 is moved to a transfer machine (not shown) of the stocker 3c.
Is transferred to the inter-process transfer vehicle 8 (path L ₁₄ ), is transferred on the inter-process transfer path 7 to the transfer point of the stocker 3 b of the production line 1 b (path L ₁₅ ), and is transferred between the steps by the transfer machine of the stocker 3 b. It is transferred from the transport vehicle 8 into the stocker 3b (path L ₁₆ ), and further transported in the in-process transport path 4b by the in-process transport vehicle 5 (path L ₁₇ ), and its transfer machine (not shown) ), It is transferred to a predetermined device of the processing device 2b.
This is set (path L ₁₈ ).

The configuration of the control system of the automatic wafer transfer system for performing the transfer described above is the same as that shown in FIG.
And it does not need to be changed. Next, the operation will be described. FIG. 2 is a flowchart showing a process for determining a temporary stocker in the inter-manufacturing line transfer control of the present invention. As shown in the drawing, when there is no free space in the stocker 3b of the next process production line 3b to which the processed wafer cassette 6 is to be sent (determination in S4 in FIG. 6), the other production line having the shortest transfer time is received. Enter the step of determining a temporary stocker in a possible state (S
8), this step S8 is the next step S9 to S1
Consists of eight. First, the transport control computer 12 reads information from the intra-process transport control computers 13a to 13h regarding whether or not the stockers 3a to 3h are empty in each of the manufacturing lines 1a to 1h (S9), and there is an empty space in the stockers 3c to 3h. A stocker is extracted (S10). Then, the transport control computer 12 reads information from the in-process transport control computers 13a to 13h regarding the presence / absence of a failure in the processing device, the stocker and the in-process transport vehicle (S11), and no failure has occurred in the stockers 3c to 3h. The stocker of the production line is extracted (S12). Next, the actual data on the transfer time between the stockers 3a to 3h of each of the production lines 1a to 1h is transferred to the intra-process transfer control computers 13a to 13h.
The transport control computer 12 obtained from 13h
Based on the latest result data, a table of the transport time between the stocker 3a and the stocker in which no failure occurs among the stockers 3c to 3h is created and stored (S13). The processing apparatuses 2a to 2h of the respective manufacturing lines 1a to 1h have different incorporation conditions depending on the manufacturing process and also depending on the time. Therefore, based on the latest actual data, the respective processing lines 2a to 1h The actual transport time between them is ascertained.

Next, based on the stored transport time table, the transport control computer 12 determines the shortest stocker 3c in the transport time from the stocker 3a to each stocker on the production line where no failure has occurred. It is obtained by calculation and determined as a temporary stocker (S14). Then, the transport control computer 12 sends an instruction to transport the cassette 6 of the stocker 3a to the temporary stocker 3c to the intra-process transport control computers 13a and 13c and the inter-process transport control computer 15 (S15). The computers 13a and 13c instruct the intra-process equipment transport control computers 14a and 14c, and the inter-process transport control computer 15 instructs the inter-process transport equipment controller 16 to transfer the inter-process transport vehicle 8 to the temporary stocker 3c. The cassette 6 is transported to the transfer point (S16), and the cassette 6 is stored in the temporary stocker 3c and waits (S17). Then, the transport control computer 12 checks whether there is an empty space in the stocker 3b of the next process manufacturing line 1b. If there is no empty space, the cassette 6 waits in the stocker 3a. The cassette 6 is transported to the transfer point to the stocker 3b (S19), and stored in the stocker 3b (S20). Next, the cassette 6 is transported and set by the intra-process transport vehicle 5 to the next process processing apparatus 2b (S
21) The inter-line transfer ends.

As described above, in the first embodiment, even if the production line 1b in the next process is not in the receiving state, the processed wafer cassette 6 stored in the stocker 3a can be stored in another stocking line. The cassette 6 containing wafers, which is transported from the previous process with the production line 1a as the next process, can be immediately stored in the cassette 3a to perform required processing smoothly, and is transported and processed as a system. Does not occur. Further, the stocker of the production line on which the cassette 6 with processed wafers is temporarily placed is selected from the production line in the receiving state under the condition that the transport time is the shortest, so that the operation rate of the entire system can be improved. This has the effect.

Embodiment 2 FIG. Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a layout schematically showing the arrangement of devices in the semiconductor manufacturing system of the present invention, and also shows the transport path of the cassette containing processed wafers to the next step. In FIG. 3, 9
And 10 are the first and second sections between the respective production lines 1a to 1h.
In each case, a plurality of inter-process carriers 8 carry a cassette 6 containing wafers, and the former runs clockwise and the latter runs counter-clockwise on the track, and the stocker of the next process manufacturing line. To the transfer point. In addition,
Each of the stockers 3a to 3h of each of the production lines 1a to 1h is provided with a transfer machine for transferring the cassette 6 between the stockers 3a to 3h and the inter-process transport vehicles 8 of the first and second inter-process transport paths 9, 10. The cassette 6 housed in each of the stockers 3a to 3h has a shorter transfer time depending on which manufacturing line the cassette is transferred to in the first and second inter-process transfer paths. Is selected.

The cassette 6 containing wafers processed in the production line 1a and stored in the stocker 3a is now transported to the next production line 1b.
If the stocker 3b has no empty space or if the processing apparatus or the in-process carrier 5 is out of order and is not in the receiving state, another manufacturing line in the receiving state is searched for, and the transport time is the shortest. , for example, the production line 1d is obtained, the cassette 6 stocker 3a transfer machine are transferred (not shown) to the interprocess transport vehicle 8 (route L _31), a first interprocess transport path 9 above The stocker 3d of the production line 1d
To the transfer point (path L ₃₂ ). Then
The stocker 3d of transfer device are transferred from the interprocess transport wheel 8 to the stocker 3d the (route L ₃₃₎ is temporarily placed. Then, when the stocker 3b of the next process manufacturing line 1b is in a receivable state, the cassette 6 is transferred to the inter-process carrier 8 by the transfer machine (not shown) of the stocker 3d (path L).
_34), until the transfer point of the stocker 3b of the second interprocess transport path 10 on the production line 1b (route L ₃₅₎ is conveyed,
Stocker by 3b of transfer device are transferred from the interprocess transport wheel 8 to the stocker 3b the (route L _36), further, the process carrying truck 5 is conveyed through the steps in the conveying path 4b (route L ₃₇₎ , The transfer device (not shown), the processing device 2b
Is the transfer set in a predetermined device (route L _38).

FIG. 4 is a block diagram showing a configuration of a control system of the automatic wafer transfer system according to the second embodiment of the present invention. As shown, in the block diagram, the inter-process transfer control computer 15 includes an inter-process transfer device controller 16a that controls the inter-process transfer vehicle 8 traveling on the first inter-process transfer path 9 and the second process. It differs from the conventional example in that it is configured to control an inter-process transport device controller 16b that controls the inter-process transport vehicle 8 traveling on the transport path 10. Other configurations are the same as those in the conventional example. That is, when finding the stocker with the shortest transport time from the stocker 3a, the transport control computer 12 communicates with the stocker 3a via the first inter-process transport path 9 and the second inter-process transport path 10 and the respective stockers 3a.
Create and store a table of the transport time between the stockers c to 3h and the stocker in which no failure has occurred. Based on the table, calculate the stocker with the shortest transport time, and calculate the inter-process transport based on the result. Equipment controllers 16a, 16
b will be selected. As mentioned above,
In the second embodiment, the semiconductor manufacturing system
In addition, since a temporary stocker that minimizes the transport time of the processed stockers is determined as having the second inter-process transport path, the transport time can be further reduced.

[0020]

As described above, the present invention has the following advantages. When transferring a processed wafer cassette to the next production line, if the next production line is not in the receiving state, the production line with the shortest transfer time on other available production lines is automatically Since it is determined and temporarily placed on the stocker until the next production line is in a receiving state, stagnation during transport of the entire system can be prevented, and the operating rate of the processing apparatus can be improved. In addition, the inter-process transport path is defined as two transport paths having mutually opposite orbits, and the production line with the shortest transport time is determined based on the transport time when transported by these inter-process transport paths. Because it was
Further shortening of the transport time and improvement of the operation rate can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an inter-process transfer method in a semiconductor system according to a first embodiment of the present invention;

FIG. 2 is a flowchart showing a process of determining a temporary stocker in the inter-manufacture-line transfer control according to the first embodiment of the present invention;

FIG. 3 is a layout diagram schematically showing an arrangement of devices in a semiconductor system according to a second embodiment of the present invention;

FIG. 4 is a block diagram showing a configuration of a control system of an automatic wafer transfer system according to a second embodiment of the present invention.

FIG. 5 is a layout diagram schematically showing the arrangement of devices in a conventional semiconductor system.

FIG. 6 is a block diagram showing a configuration of a control system of a conventional automatic wafer transfer system.

FIG. 7 is a flowchart showing a conventional transfer control between production lines.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Production line 2; Processing device 3; Stocker
4; intra-process transport path 5; intra-process transport vehicle 6; cassette 7; inter-process transport route 8; inter-process transport vehicle 9; first inter-process transport route 10; second inter-process transport route 11; 12; transfer control computer 13; in-process transfer control computer 14; in-process equipment controller 15; inter-process transfer control computer 16;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuo Kanai 4-1-1 Mizuhara, Itami-shi, Hyogo Ryoden Semiconductor System Engineering Co., Ltd. (72) Suzue Nakanishi 4-1-1 Mizuhara, Itami-shi, Hyogo Ryoden Semiconductor System Engineering Co., Ltd. F-term (reference) 5F031 CA02 DA01 FA01 FA03 GA58 MA09 MA13 MA26 MA27 MA28 MA31 PA03

Claims (2)

[Claims] 1. A plurality of processing apparatuses for performing required processing of a wafer, a stocker for temporarily storing a cassette containing wafers before and after the processing, and a cassette provided between the processing apparatus and the stocker, the cassette being provided therebetween. It has an in-process conveyance path that is a path to be conveyed, and has at least one production line corresponding to each of a plurality of production steps, and is provided by connecting stockers of each of the production lines, and is provided for process progress. An automatic wafer transfer system, comprising: an inter-process transfer path which is a path for transferring the cassette between the stockers in accordance therewith, and automatically controlling the transfer of the cassette by the transfer vehicle in the in-process transfer path and the inter-process transfer path by a computer. In the transfer control method according to the above, the control by the computer is performed at the scheduled transfer destination of the next process of the predetermined processed wafer cassette. A first step of recognizing that a certain production line is not in a receiving state and searching for a stocker of another production line on which the cassette can be temporarily placed; And the second step of finding a production line in which the transport time from the stocker of the processed production line is the shortest among the stored production lines, A transfer control method in an automatic wafer transfer system, comprising a third step of storing the cassette in a stocker of a shortest production line until the next production line is in a receiving state. 2. The inter-process transport path includes first and second inter-process transport paths having mutually opposite trajectories connecting between stockers, and the transport determined in the second step. 2. The production line having the shortest time is determined based on the transport time when the wafer is transported by the first and second inter-process transport paths.
Transfer control method in the automatic wafer transfer system described in the above.