JPH04318911A - Method of controlling processing process in multikind manufacture line - Google Patents

Abstract

PURPOSE:To simply and easily control the processing process different by a work in a multikind manufacture line and lighten the burden of the computer, etc., of a CPU which controls the manufacture line at large. CONSTITUTION:An identification code is declared in advance in every work, and each time the work is processed in each process, the history information in the process is declared in the work in order.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a method for controlling processing steps in a multi-product manufacturing line, and more specifically, the present invention relates to a method for controlling processing steps in a multi-product manufacturing line. In a so-called multi-product manufacturing line, which manufactures products and performs different processing on each workpiece on a single production line, making it possible to continuously manufacture a wide variety of products, different processing is performed on each workpiece. It relates to a method for managing processes.

0002

BACKGROUND OF THE INVENTION In recent years, in order to rationalize manufacturing equipment and save labor, a single manufacturing line has been designed to be able to manufacture different types of products. In this case, instead of stopping the production line and changing the setup and layout of each processing step each time the product type is changed, the production line continues to operate and changes are made for each workpiece in each processing step. The operating rate and productivity of the entire manufacturing line are increased by processing the workpiece or by changing the transport route of the workpiece to supply the workpiece only to necessary processing steps.

For example, in a semiconductor device manufacturing line, a semiconductor substrate, which is a workpiece, undergoes a thin film forming process, a pattern forming process by photolithography, a selective etching process, a process of introducing impurities into the substrate, etc. , is repeated many times to form a predetermined element structure on the substrate. Therefore, an extremely large number of processing steps are performed on one semiconductor substrate. In addition, in semiconductor equipment, in response to various customer demands,
It is necessary to provide a variety of products with different circuit structures and element functions, and a single production line is required to manufacture a wide variety of products by changing the processing steps depending on the substrate.

[0004] In such a multi-product production line,
It is necessary to accurately manage the different processing steps for each workpiece, such as what kind of processing should be performed next for each type of workpiece, and what processing stage a particular workpiece is currently in. .

In a conventional semiconductor device manufacturing line, several dozen semiconductor substrates are housed in a box-shaped magazine, and an ID card for storing information is attached to the outside of the magazine. Identification numbers for each accommodated semiconductor substrate and history information for each processing step are written in this ID card. A central processing unit consisting of a computer, etc. that centrally manages the entire production line grasps the progress status of the processing process of the semiconductor substrates housed in the magazines from the information read from the ID cards attached to each magazine. ,
Instructions are given to the magazine conveying means and the processing equipment for each processing step to control their operations, such as which processing step the magazine should be transported to next or the processing conditions for that processing step.

[0006] This method is extremely useful in manufacturing lines where relatively small workpieces must be handled in large quantities and in many different types, since the processing process can be managed collectively for each magazine. It is used because it is efficient.

[0007]

[Problems to be Solved by the Invention] However, as described above, in the method of storing and managing workpieces in magazines,
Even when it is desired to perform a specific machining process on only one or a small number of workpieces, a bulky magazine with a capacity for several tens of workpieces as described above must be used, which is extremely uneconomical. It is. Another problem is that it takes time and effort to take the workpieces in and out of the magazine.

[0008] Therefore, an identification code such as a bar code is written on each workpiece, and a central processing unit such as the computer is used to write the identification code of each workpiece and the current status of the workpiece. One idea was to manage information such as what processing steps have been performed up to now and what processing steps need to be performed next, and issue the necessary instructions. However, with this method, the central processing unit
Because it is necessary to constantly grasp the processing progress of each individual workpiece, a large amount of information must be managed, which increases the load on computers, etc., and requires prompt and appropriate management control. becomes impossible. In order to solve this problem, it would be possible to increase the capacity and performance of computers, etc., but this would increase the equipment cost of the manufacturing line and increase production costs. The benefits of eliminating waste through abolishment will no longer be realized.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a central processing unit computer that can easily and reliably manage processing steps for each workpiece in a multi-product manufacturing line as described above, and that manages and controls the entire manufacturing line. It is an object of the present invention to provide a method for managing processing processes that can reduce the burden of processing.

0010

[Means for Solving the Problems] A method for managing processing steps in a multi-product production line according to the present invention that solves the above-mentioned problems is to perform different processing depending on the workpiece in a production line including a plurality of processing steps. , is a method for managing the processing process for each workpiece when manufacturing a wide variety of products continuously.In addition to marking each workpiece with an identification code, Each time a process is performed, history information for that process is written on the workpiece.

[0011] The workpiece is preferably applied to a workpiece that is relatively small in size, such as a semiconductor substrate for manufacturing the above-mentioned semiconductor device, and is used for manufacturing a wide variety of products in large quantities. . If the workpiece, such as a semiconductor substrate, undergoes a pattern formation process by photolithography or a printing process in the processing process, at the same time as the processing process,
It is now possible to write history information, which will be described later.
This is particularly preferable.

[0012] The identification code is a code that is a combination of a series of numbers, symbols, etc. attached to each workpiece, and is used to identify each workpiece. As the identification code, it is convenient to use not only human-readable numbers and symbols but also codes suitable for machine identification, such as bar codes, for management in a central processing unit such as a computer. The identification code is written on the workpiece using a printing device such as a printer, photolithography technology, or microfabrication technology. The central processing unit determines the product type to be manufactured for each identification code, and selects the processing steps required for each product type. The identification code can be provided at any position or size on the surface of the workpiece as long as it does not interfere with the function or performance of the product.

[0013] In addition to the above-mentioned identification code, history information in each processing step is written on the workpiece. The history information may include information such as processing conditions and finished state in the processing step, in addition to information clarifying that each processing step has been completed. This history information is also written into the workpiece using the same means as the identification code. The history information may be added at a position adjacent to the identification code, or may be added at a position different from the identification code at a position that does not interfere with the function or performance of the product. In addition, history information can be deleted when it is no longer needed, so you can install a structural part necessary for the product in the location where the history information was attached, or
It can also be processed.

[0014] The history information is read by an information acquisition means such as an optical sensor connected to the central processing unit before entering each processing step or at a branch point in the conveyance route of the workpiece. It determines whether to perform a machining process or how to set the machining conditions for that machining process, and issues necessary commands to transport means, processing equipment, etc.

[0015] The information acquisition means can use various information reading sensors that read information optically, mechanically, or electromagnetically, depending on the notation method of the identification code and history information.

[0016] Once the central processing unit issues the command, the history information of the workpiece may be discarded. That is, at each point in time, the central processing unit only has to determine the next command based on the identification code of the workpiece and the history information at that stage.

[0017] In each machining process, the history information for that machining process may be added to the history information for the previous machining process, or the history information for the previous machining process may be erased and then History information for the current machining process may be added to the file. That is, in the present invention, at each stage, it is only necessary for the central processing unit to know only the history information and the identification code of the workpiece in the immediately preceding machining process.

[0018] In the process management method according to the present invention, the arrangement of the process steps in the production line, the types of process steps, etc. can be arbitrarily set. Basically, a large number of process sections are lined up on the transport path of the workpiece, so that the workpiece is transported in one direction and the necessary processing is sequentially performed at appropriate positions along the way. be. When a workpiece does not require processing in a specific process section, a bypass section is provided in the conveyance path so that the workpiece can be conveyed to the next process section without passing through such a process section. If there are two processing procedures that are selectively adopted depending on the workpiece, the two processing lines may be branched in the middle of the production line and then merged together again. Furthermore, a plurality of processing steps can be provided at the ends of the radial conveyance path, and the workpiece can be supplied to any of the processing steps in any order to perform the necessary processing. .

[0019]

[Operation] In order to manufacture different types of products, there are processing steps and processing conditions required for each type, and such processing information is stored on a computer equipped with a computer etc. that manages the entire production line. Managing with a central processing unit is a conventional method. Also, for each workpiece,
A method is also known in which a series of identification codes such as manufacturing numbers are attached and process control is performed using these identification codes.

[0020] In this invention, instead of storing the workpieces all together in a magazine or the like, each workpiece is
Each product is sent to the production line separately with its identification code written on it. The central processing unit that manages the entire production line identifies the type of product to be manufactured from each workpiece for each identification code.
Alternatively, information on processing steps and processing conditions to be applied to each workpiece is held.

[0021] On the production line, the identification code marked on the workpiece and its identification code are displayed on the transport path of the workpiece at a stage before entering each processing step or at a branch point to multiple processing lines. Read the history information added in the previous processing steps. From the processing information and identification code for each type stored in the central processing unit, it can be determined in what order or under what conditions the workpiece should be processed. From the history information, you can see to what stage the workpiece has been processed, so based on this information, you can determine which processing line the workpiece should be sent to next. Or, you can know what kind of processing should be performed in the next processing step. As a result, the central processing unit can issue necessary commands to the transfer path branching device or the processing device for the next processing step.

[0022] When one machining process is completed, history information for that machining process is written on the workpiece, and then the workpiece is sent to the conveyance path or to the next process.

[0023] In this way, the central processing unit that manages the entire production line can always receive detailed information such as which processing stage the workpiece is in, or the processing process to be sent next and its processing conditions. There is no need to manage the workpiece, and when the identification code and history information described above are read, it is sufficient to make a judgment based on these two pieces of information and issue a command necessary for the next processing of the workpiece. After issuing this command, there is no need to maintain historical information about the workpiece in the central processing unit. In other words, the workpiece is
Since the workpiece itself has information on which processing stage it is in, that is, history information, there is no need for the central processing unit to manage it.

[0024] If the production line stops due to a malfunction or other cause, processing of the workpiece may be interrupted, or when a certain processing step is completed, the workpiece may be temporarily removed from the production line and stored. Even if the workpiece is left in the machine, the process up to which the workpiece has been processed is written in the workpiece itself as history information, so even if the central processing unit does not manage it at all, the production line can be controlled. When the machine is restarted or the workpiece is supplied to an intermediate processing step, it is possible to reliably proceed to the next correct processing step without any problems.

[0025]

Embodiments Next, embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a method of controlling processing steps according to the present invention. The flow or conveyance path 50 of the workpiece is shown by a double line, and the workpiece moves along the direction of the white arrow. Different processing steps are performed in the four processing sections 20 of processes A to D.

FIG. 2 shows a specific example of the structure of the workpiece, which is a semiconductor substrate 10 for manufacturing a semiconductor device. The semiconductor substrate 10 has a small rectangular shape, and various electronic circuits and element structures are formed on its surface to form a semiconductor device. A display section 12 is provided at a corner of the surface of the semiconductor substrate 10 that does not affect the circuit structure. On the display section 12, a code for identifying each semiconductor substrate 10, that is, an identification code is written in the form of a bar code. Further, the display section 12 can also display history information for each processing step.

A case will be described in which a semiconductor device is manufactured from the semiconductor substrate 10 as described above through various processing steps.

In FIG. 1, processing section 2 of steps A to D
0 includes a step of forming a thin film of an insulating film, a conductive film, and other various functional films on the surface of the semiconductor substrate 10, a step of patterning the formed thin film by photolithography or selective etching,
A process of ion-implanting impurity elements, a process of heat treatment,
A suitable combination of cleaning steps and various other processing steps required in a normal semiconductor device manufacturing line is arranged. The conveyance path 40 is composed of ordinary conveyance means such as a conveyor, and carries a large number of semiconductor substrates 10.
are sequentially and continuously fed into each processing section 20.

Before the semiconductor substrate 10 enters the first step A, an identification code written on the display section 12 is read by an information acquisition section 30 equipped with an optical sensor or the like. The information acquisition unit 30 is a central processing unit 40 that manages the entire manufacturing line.
The read information is sent to the central processing unit 40.
sent to. The flow of information is shown by dotted lines.

The central processing unit 40 is composed of an electronic device such as a computer, and controls the operation of the processing devices in each process section A to D, the operation of the branching mechanism of the transport path 40, and the like. The flow of control commands from the central processing unit 40 to the processing section 20 for each process A to D is shown by a solid line. Central processing unit 4
0, information such as necessary processing steps and processing conditions, that is, processing information, is stored in advance for each identification code of the semiconductor substrate 10, and from this processing information and the information of the identification code read by the reading means 20, this With respect to the semiconductor substrate 10,
Determine whether processing in step A is necessary. If processing in step A is required, the semiconductor substrate 10 is sent to the transport path 50 that connects to the processing section 20 in step A, and if necessary, processing conditions etc. are sent to the processing equipment in the processing section 20 in step A. Issue a command to set. If processing in the process is not necessary, the semiconductor substrate 10 is sent to the transport path 50 leading to the next process B.

In step A, history information is written at the same time as the semiconductor substrate 10 is subjected to a predetermined process. As the history information, a code indicating that the processing in step A has been completed is printed or written on the display section of the semiconductor substrate 10. Specifically, in step A, various patterns are formed on the semiconductor substrate 10 using photolithography, so history information is written at the same time as the pattern formation. Therefore, the history entry section for writing history information is not provided independently, but the processing section of process A itself serves as the history entry section. The semiconductor substrate 10 on which the history has been written is returned to the transport path 40 for the next step B.

An information acquisition section 30 is also provided in front of the processing section 20 in step B, and the identification code written on the display section 12 and the history information entered in step A are acquired. The central processing unit 40 determines whether or not processing in step B is necessary following processing in step A, based on processing information specific to this semiconductor substrate 10, which can be seen from the identification code, and history information. If processing in step B is unnecessary, the semiconductor substrate 10 may be sent to the transport path 40 leading to the next processing step, and if processing in step B is necessary, the same processing as described above may be performed.

Once the central processing unit 40 issues a command to the transport path 50 to change the transport direction of the semiconductor substrate 10 and an instruction to the processing conditions for the processing equipment provided in the processing section 20 of process B, the semiconductor There is no need to retain the history information of the board 10, and the information may be discarded. That is, in the central processing unit 40, each semiconductor substrate 1
There is no need to accumulate information on which processing stage 0 is currently in over time, and necessary judgments and commands can be made as soon as the information from the information acquisition means 30, that is, the identification code and the latest history information, is received. All you have to do is send the message.

[0035] On the display section 12 of the semiconductor substrate 10 that has been processed in step B, history information indicating the completion of processing is written, as in step A. Note that step B is the same as the step A.
Similarly, when pattern formation is performed by photolithography or the like as a processing step, the history information may be entered at the same time as the processing step, or if it cannot be entered during the processing step, it can be continued in the processing step section 20 of step B. Additionally, a history entry section for printing history information may be provided.

[0036] As in steps A and B, the machining process sections 20 and 2
In the case where the 0's are arranged in a straight line, the necessary processing steps can be sequentially performed on the semiconductor substrate 10 by repeating the above process.

Next, process C and process D are cases in which it is sufficient to selectively perform either process. The conveyance path 40 includes processing sections 20 and 20 for process C and process D, respectively.
An information acquisition section 30 is provided before the branch point where the information is divided into two sections, and from the history information and identification code acquired here,
The central processing unit 40 may determine whether the semiconductor substrate 10 should be sent to process C or process D.

The arrangement of each process A to D and the layout of the conveyance path 50 can be freely changed in addition to those shown in the drawings according to the type of processing process required. In any case, the information acquisition means 30 is always provided at a location where it is necessary to select the transportation direction of the semiconductor substrate 10, that is, at a branch point of the transportation path 50, or at a position in front of each process section.
It is only necessary to be able to determine the next processing step and conveyance direction.

Next, FIG. 3 shows a specific example of history information. (A) to (c) are steps A to C, respectively.
This is history information at the stage where the process has been completed, and uses a barcode type code. It should be noted that the identification code may also be written as a normal bar code type code, and the identification code will not be changed during the processing process, so a description thereof will be omitted.

First, when step A is finished, in addition to the start position S and end position E of the barcode,
A bar line will be drawn at the position. If the above-mentioned barcode is read by the information acquisition unit 30 before the step B, it can be seen that the semiconductor substrate 10 has been processed in the step A.

At the stage where process B is completed, a bar line is drawn next to position 1 indicating the completion of process A, that is, at position 2, and when process C is completed, a bar line is drawn at position 3 next to it. Filled out. In this way, each time the wire rod is passed through a different position. By simply reading this barcode, it is possible to accurately determine which processing steps have been completed on this semiconductor substrate 10.

[0042] In each process, in addition to the information indicating that the machining process has been completed, specific machining conditions, finished state, and other information may be added and written as history information. In this case, it is sufficient to write a barcode that is a combination of multiple bars with different thicknesses and intervals that represent a more complex code.

Next, FIG. 4 shows a method of representing history information that can reliably prevent reading errors. Similarly to the above example, each step A to (c) is performed in (A) to (c).
It shows the history information written at the stage of completing C.

First, in step A, in addition to the number 1, a black □ (a figure with a square frame filled in) is written on the left side, and a △ is written on the right side. The information acquisition means 30 before step B reads the numbers between the black □ and △. In this case, the number 1 is read, indicating that the processing in step A has been completed.

Next, in step B, the numbers 1 and △ written in step A are overwritten with black □, the numbers 1 and △ are painted over and erased, and the numbers 2 and △ are written next to them. Fill out. The information acquisition unit 30 before step C reads the numbers between the black △ and △, and reads the number 2 indicating that step B has been completed, in the same manner as described above.

[0046] In this way, in the information acquisition section 30,
Since only the numbers between the black □ and △ are read at all times, there are no missed readings or misreadings.

This is because, for example, when the bar code is expressed only by the position or number of bars as in the embodiment shown in FIG. , the bar line may not be clearly printed, and the bar line indicating the latest process (in (c) of Figure 3, it is the process C).
If you fail to read the bar at position 3 (which indicates 3), you may conclude that the previous step has been completed.

However, as in the embodiment shown in FIG. 4, if the numbers in the history information entered in the previous process are erased by filling them in with black □, only the history information in the latest process will be displayed in black □ and △.
Since it is definitely written in the position between the clear symbols, there is no need to worry about reading the wrong symbol.

[0049]

[Effects of the Invention] According to the method for controlling processing steps in a multi-product production line according to the present invention described above, by marking two pieces of information, an identification code and history information, on a workpiece, The burden on the computer of the central processing unit can be significantly reduced. In other words, by allowing the workpiece itself to have historical information on the machining process of the workpiece, which was conventionally managed centrally in a central processing unit, the information can be different for each of the many workpieces. This eliminates the need for the central processing unit to perform the extremely complicated and burdensome task of managing historical information that constantly changes over time.

[0050] If the burden on the central processing unit is lightened, the capacity of the computer, etc. will be reduced, making it possible to simplify the equipment and to allocate the computer's ability to other tasks. Also, if the computer capacity is the same,
It is now possible to simultaneously process a larger number of workpieces on the same production line, contributing to improved productivity on the production line.

[Brief explanation of drawings]

[Fig. 1] A schematic layout diagram of a manufacturing line showing an embodiment of this invention

[Figure 2] Perspective view showing a specific example of the workpiece

[Figure 3]
Explanatory diagram showing a specific example of history information

[Figure 4] Explanatory diagram showing another specific example of history information

[Explanation of symbols]

10 Workpiece 20 Processing process department and history entry department 30 Information acquisition department 40 Central processing unit 50 Transport route

Claims (2)

[Claims] [Claim 1] A production line including multiple processing steps,
This is a method of managing the processing process for each workpiece when manufacturing a wide variety of products continuously by performing different processing on different workpieces, and by marking each workpiece with an identification code. A method for managing machining processes in a multi-product manufacturing line, characterized in that, each time the workpiece is processed in each machining process, history information in the machining process is written on the workpiece. 2. The method for managing machining processes according to claim 1, wherein in each machining process, history information for that machining process is written on the workpiece, and history information written for previous machining processes is erased.