JP3158472B2 - Management method of machining process in multi-product line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for managing processing steps in a multi-product line, and more particularly, to a method for processing a workpiece in a plurality of processing steps like a semiconductor device manufacturing line. In a so-called multi-product manufacturing line, different types of processing are performed in a so-called multi-product manufacturing line that manufactures products and performs different types of processing on the workpieces in one manufacturing line so that multiple types of products can be manufactured continuously. The present invention relates to a method for managing a process.

[0002]

2. Description of the Related Art In recent years, in order to rationalize manufacturing equipment and save labor, it has been practiced that one type of manufacturing line can manufacture products of different types. In this case, each time the type is changed, the production line is continuously operated while the production line differs for each workpiece in each processing step, instead of temporarily stopping the production line and changing the setup and arrangement of each processing step. 2. Description of the Related Art An operation rate and productivity of an entire production line are increased by performing a processing process or changing a conveyance path of a workpiece and supplying the workpiece only to a necessary processing step.

For example, in a semiconductor device manufacturing line, a process of forming a thin film, a process of forming a pattern by photolithography, a selective etching process, and a process of introducing impurities into a substrate are performed on a semiconductor substrate to be processed. By repeating the process many times, a predetermined element structure is formed on the substrate. Therefore, an extremely large number of processing steps are performed on one semiconductor substrate.
In addition, in semiconductor devices, according to various requirements of customers,
It is necessary to provide a variety of products having different circuit structures and element functions, and it is required to manufacture various types of products in one manufacturing line by changing processing steps depending on a substrate.

In such a multi-product manufacturing line,
It is necessary to accurately manage different processing steps for each workpiece, such as what kind of processing is to be performed next for each type of workpiece and what processing stage is currently in progress for a specific workpiece. .

In a conventional semiconductor device manufacturing line, several tens of semiconductor substrates are housed in a box-shaped magazine, and an ID for storing information is placed on an outer surface of the magazine.
Insert the card. In this ID card, an identification number for each semiconductor substrate contained therein and history information for each processing step are written. In a central processing unit including a computer or the like that centrally manages the entire production line, information on reading an ID card attached to each magazine is used to grasp the progress of the process of processing a semiconductor substrate housed in the magazine. Then, a command is sent to a magazine conveying means, a processing device for each processing step, and the like to determine which processing step is to be transferred next, or processing conditions in the processing step, and the operation is controlled.

According to this method, in a production line in which a relatively small work piece needs to be handled in a large number of varieties and handled in large quantities, the processing steps can be managed collectively for each magazine. It is used to be efficient.

[0007]

However, as described above, in the method of storing and managing a workpiece in a magazine,
Even when only one or a small number of workpieces are to be subjected to a specific processing step, a bulky magazine having a capacity of several tens of sheets as described above must be used, which is extremely uneconomical. It is. In addition, there is a problem that it takes time to take the work in and out of the magazine.

Therefore, an identification code such as a bar code is written for each individual workpiece, and the identification code of each workpiece and the identification code of the workpiece are stored in a central processing unit such as the computer. It has been conceived to manage information such as what processing steps have been performed by then and what processing steps need to be performed, and to issue necessary commands. However, in this method, in the central processing unit,
Since it is necessary to keep track of the progress of machining for each individual work piece, a large amount of information must be managed, and the load on the computer etc. will increase too much, and prompt and appropriate management control Becomes impossible. In order to solve such a problem, it is only necessary to increase the capacity or capacity of a computer or the like.However, this increases the equipment cost of the production line and increases the production cost. The advantage of eliminating it and eliminating waste cannot be exhibited.

An object of the present invention is to provide a computer for a central processing unit which can easily and reliably manage the processing steps for each workpiece in the above-described multi-product line and manage and control the entire manufacturing line. It is an object of the present invention to provide a method for managing a processing step capable of reducing the burden on the processing steps.

[0010]

[Means for Solving the Problems] In order to solve the above-mentioned problems
In addition, the method for managing processing steps in a multi-product line according to the present invention is a manufacturing line including a plurality of processing steps,
Performing different machining by workpiece, in the continuous production of products of various kinds, the A method of managing a machining process for each workpiece, title identification codes for each of the workpiece together keep said each time the workpiece is subjected to machining in each machining step, before the history information in the processing step
Notation on the workpiece and notation in each processing step up to that time
The deleted history information is deleted when it is no longer necessary .

The workpiece is preferably applied to a workpiece having a relatively small size, such as a semiconductor substrate for manufacturing the above-described semiconductor device, and used for mass-producing a large variety of products. . In the case of a processing object such as a semiconductor substrate, in which a pattern forming step by photolithography or a printing step is performed in a processing step, simultaneously with the processing step,
It is possible to write history information described later,
It becomes particularly preferable.

The identification code is used to identify individual workpieces by assigning a code obtained by combining a series of numbers and symbols for each workpiece. As the identification code, not only a human-readable number or symbol but also a code suitable for identification by a machine, such as a bar code, is convenient for management in a central processing unit such as a computer. The identification code is written on the workpiece using a printing means such as a printer, a printing means, or a photomechanical technology or a fine processing technology. In the central processing unit, a type to be manufactured is determined for each identification code, and a processing step required for each type is selected. The identification code can be provided at any position or size on the surface of the workpiece as long as it does not hinder the function or performance of the product.

On the workpiece, in addition to the identification code, history information in each processing step is written. The history information may include information such as processing conditions and a finished state in each processing step, in addition to information for clarifying that each processing step has been completed. This history information is also written on the workpiece by the same means as the identification code. History information is
It may be added at a position adjacent to the identification code, or may be added at a position different from the identification code and at a position that does not hinder the function or performance of the product. Further, since the history information may be deleted when it is no longer necessary, it is possible to provide a necessary structural portion to the product at the position where the history information is added, or to perform processing.

The history information is read by 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 transport path of the workpiece. It determines whether to perform the processing step or how to set the processing conditions in the processing step, and issues necessary commands to the transporting unit, the processing device, and the like.

The information acquisition means can use various information reading sensors that read information optically, mechanically, or electromagnetically in accordance with the notation method of the identification code and the history information.

In the central processing unit, once the command is issued, the history information of the workpiece may be discarded. That is, in the central processing unit, at each time point, the next command may be determined only from the identification code of the workpiece and the history information at that stage.

In each processing step, the history information in the processing step may be added to the history information in the previous processing step, or the history information in the previous processing step may be deleted, and May be added to the history information of the current processing step. That is, in the present invention, at each stage, only the history information in the immediately preceding machining step and the identification code of the workpiece need to be known by the central processing unit.

In the method of managing a processing step according to the present invention, the arrangement of the processing steps in the production line, the type of the processing step, and the like can be arbitrarily set. Basically, there are a number of process units arranged on the transport path of the workpiece so that the workpiece is transported in one direction and the necessary processing is sequentially performed at an appropriate position in the middle. is there. If processing in a specific process section is not necessary depending on the workpiece, a bypass portion that can transport the workpiece to the next process section without passing through such a process section is provided in the transport path. If there are two processing procedures that are selectively adopted depending on the workpiece, it may be branched into two processing lines in the middle of the production line and then joined again. Furthermore, a plurality of processing steps may be provided at the end of the radial transport path, and the workpiece may be supplied to any one of the processing steps in an arbitrary order to perform necessary processing. .

[0019]

In order to manufacture products of different types, there are processing steps and processing conditions necessary for each type, and such processing information is provided by a computer or the like which manages the entire production line. The management by the central processing unit is a conventional method. There is also known a method in which an identification code such as a series of serial numbers is assigned to each workpiece, and process management is performed using the identification code.

According to the present invention, the workpieces are not stored collectively in a magazine or the like.
In a state where each identification code is written, the product is separately flown to the production line. In a central processing unit that manages the entire production line, information on the type of a product manufactured from each workpiece or the processing steps and processing conditions applied to each workpiece is stored for each identification code.

In the production line, at the stage before entering each machining step in the transport path of the workpiece, or at a branch point to a plurality of machining lines, an identification code written on the workpiece and The history information added in the processing steps up to is read. From the processing information for each product type and the identification code stored in the central processing unit, it is possible to know in what order or under what conditions the workpiece should be processed. Then, from the history information, it is known to what stage the workpiece has been processed, and based on this information, the workpiece can be sent to which processing line next. Or what kind of processing should be performed in the next processing step. As a result, a necessary command can be issued from the central processing unit to the transfer path branching device or the processing device for the next processing step.

When one processing step is completed, the history information in the processing step is written on the workpiece, and then sent to the transport path or the next step.

In this way, the central processing unit that manages the entire production line always provides detailed information such as the processing stage of the workpiece or the processing step to be fed next and the processing conditions. It is not necessary to manage the information, and when the identification code and the history information are read, it is only necessary to judge from these two information and issue a command necessary for the next processing for the workpiece. After issuing this command, there is no need to keep history information about the work in the central processing unit. That is, since the information on the processing stage of the workpiece, that is, the history information, is possessed by the workpiece itself, it is not necessary to manage the central processing unit.

When the production line is stopped due to a failure or other causes, the processing of the workpiece is interrupted, or when a certain processing step is completed, the workpiece is temporarily removed from the production line and stored. Even in the case where the workpiece has been processed, the stage to which the workpiece has been processed is written as history information in the workpiece itself, so even if the central processing unit does not manage it at all, the production line can be processed. When restarting or supplying the workpiece to an intermediate processing step, the process can be reliably continued to the next correct processing step without any problem.

[0025]

Next, an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a method for managing a processing step according to the present invention. The flow of the workpiece or the transport path 50 is indicated by a double line, and the workpiece moves in the direction of the white arrow. Different processing steps are performed in each of the four processing steps 20 of the steps A to D.

FIG. 2 shows a specific example of the structure of a 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 the surface thereof to configure a semiconductor device. The display unit 12 is provided at a corner of the surface of the semiconductor substrate 10 which does not affect the circuit structure. On the display unit 12, a code for identifying each semiconductor substrate 10, that is, an identification code is indicated by a bar code. The display unit 12 can also display history information in each processing step.

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

In FIG. 1, a processing step 2 of steps A to D
0 is a step of forming a thin film of an insulating film, a conductive film or 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 step of ion-implanting an impurity element, a step of performing a heat treatment,
The cleaning step and other appropriate processing steps among various processing steps required in a normal semiconductor device manufacturing line are arranged in combination. The transfer path 40 is constituted by ordinary transfer means such as a conveyor, and includes a large number of semiconductor substrates 10.
Are sequentially and successively sent to each processing section 20.

Before the first step A of the semiconductor substrate 10, the identification code written on the display unit 12 is read by the information acquisition unit 30 having an optical sensor and the like. The information acquisition unit 30 includes a central processing unit 40 that manages the entire production line.
Is connected to the central processing unit 40.
Sent to. The flow of information is indicated 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 unit in each of the processing units A to D, the operation of the branching mechanism of the transport path 40, and the like.
The flow of a control command from the central processing unit 40 to the machining process unit 20 in each of the processes A to D is indicated by a solid line. Central processing unit 4
In the case of 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. For the semiconductor substrate 10,
It is determined whether the processing in the process A is necessary. If the processing in the step A is necessary, the semiconductor substrate 10 is sent to the transport path 50 leading to the processing step unit 20 in the step A, and the processing conditions and the like are set to the processing device of the processing step unit 20 in the step A as necessary. Issue a command to set. If the processing in the step is unnecessary, the semiconductor substrate 10 is sent out to the transport path 50 leading to the next step B.

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

An information acquisition unit 30 is also provided before the processing unit 20 in the process B, and acquires the identification code written on the display unit 12 and the history information entered in the process A. The central processing unit 40 determines from the processing information unique to the semiconductor substrate 10, which is known from the identification code, and the history information whether or not the processing in the process B is necessary after the processing in the process A.
If the processing in the step B is unnecessary, the semiconductor substrate 10 is sent to the transport path 40 leading to the next processing step, and if the processing in the step B is required, the same processing as described above may be performed.

If the central processing unit 40 issues a command to change the transfer direction of the semiconductor substrate 10 to the transfer path 50 or an instruction of the processing conditions for the processing device provided in the processing unit 20 in the process B, the semiconductor processing unit It is not necessary to hold the history information of the substrate 10, and the information may be discarded. That is, in the central processing unit 40, each semiconductor substrate 1
It is not necessary to accumulate information indicating which machining stage is currently 0 with time, and at the stage where the information from the information acquisition means 30, that is, the identification code and the latest history information, are included, necessary judgments and instructions for commands are made. You just have to make a call.

As in the case of the step A, history information indicating the completion of the processing is entered in the display section 12 of the semiconductor substrate 10 after the processing in the step B. Step B is the same as step A
Similarly to the above, when a pattern is formed by a photoengraving technique or the like as a processing step, history information may be entered at the same time as the processing step. A history entry unit for printing and printing history information may be provided.

As in the steps A and B, the processing steps 20, 2
In the case where 0s are provided linearly, by repeating the above-described processing, necessary processing steps for the semiconductor substrate 10 can be sequentially performed.

Next, Step C and Step D are cases where any one of the processing steps may be selectively performed. In the transport path 40, each of the processing steps 20 and 20 of the process C and the process D
An information acquisition unit 30 is provided in front of a branching point where the information is divided into two.
The central processing unit 40 may determine whether the semiconductor substrate 10 should be sent to the step C or the step D.

The arrangement of each of the steps A to D and the layout of the transport path 50 can be freely changed in addition to the illustrated ones according to the type of required processing steps. In any case, the information acquisition unit 30 must be provided at a location where the transport direction of the semiconductor substrate 10 needs to be selected, that is, at a branch point of the transport route 50 or at a position before each process unit.
What is necessary is just to be able to determine the next processing step and the transport direction.

Next, FIG. 3 shows a specific example of the history information. (A) to (c) are pieces of history information at the stage when the processes A to C have been completed, respectively, and use bar code type codes. Note that the identification code may be a normal barcode type code, and the description is omitted because the identification code is not changed by a processing step.

First, at the stage when the process A is completed, in addition to the start position S and the end position E of the barcode, 1
A bar is drawn at the position. If the barcode is read by the information acquisition unit 30 before the process B, it is understood that the semiconductor substrate 10 has been processed in the process A.

At the stage where the process B is completed, a bar is drawn next to the position 1 indicating the completion of the process A, that is, at the position 2, and when the process C is completed, a bar is drawn at the position 3 next to the bar. Filled out. In this way, the bar passes through different positions each time the process is performed. By simply reading this bar code, it is possible to accurately grasp which processing step the semiconductor substrate 10 has completed.

In each step, in addition to the information indicating that the processing step has been completed, specific processing conditions, the finished state thereof, and other information may be added and described as history information. In this case, a barcode combining a plurality of bars having different thicknesses and different intervals representing more complicated codes may be entered.

Next, FIG. 4 shows a notation method of history information that can reliably prevent reading errors. Similarly to the above embodiment, (A) to (c) show the history information described at the stage when each process A to C is completed.

First, in step A, in addition to the numeral 1, a black square (a figure in which a square frame is filled) is added to the left side of the numeral.
Write △ on the right. Information acquisition means 30 before step B
Now read the numbers between the black squares and the triangles. In this case, the number 1 is read, and it is understood that the processing in the process A is completed.

Next, in step B, black □ is overwritten on the numbers 1 and △ entered in step A, and the numbers 1 and 塗 り are painted out, and the numbers 2 and に are written next to them. Fill out. In the information acquisition unit 30 before the process C, as described above,
The number between the black squares and the black squares is read, and the number 2 indicating that the process B is completed is read.

As described above, in the information acquisition unit 30,
Since only the numbers existing between the black squares and the black squares are read at all times, there is no omission or misreading.

This is because, for example, when only the position or the number of the bar code bar is used, as in the embodiment of FIG. 3, the reading accuracy of the information acquisition unit 30 is poor. If the bar line is not clearly printed, and the bar line indicating the latest process (in FIG. 3 (c), the bar line at the position 3 indicating the process C) is missed, the immediately preceding process is There is a possibility that it is determined that the process is completed.

However, as in the embodiment shown in FIG. 4, if the numbers of the history information entered in the previous process are painted out with black squares and erased, only the history information in the latest process becomes black and square.
Is clearly written at the position between the clear codes, so there is no need to worry about reading the wrong code.

[0049]

According to the above-described method of managing a processing step in a multi-product manufacturing line according to the present invention, by writing two pieces of information, ie, an identification code and history information, on a workpiece, The burden on the computer and the like of the central processing unit can be greatly reduced. That is, conventionally, the history information of the processing steps of the workpiece, which has been centrally managed by the central processing unit, is stored in the workpiece itself, so that the history information is different for each of a large number of workpieces. This eliminates the need for the central processing unit to perform an extremely complicated and burdensome operation of managing history information that constantly changes over time.

If the load on the central processing unit is reduced, the capacity of the computer and the like can be reduced, the equipment can be simplified, and the capability of the computer can be used for other tasks. Further, if the capacity of the computer is the same, it is possible to simultaneously process a larger amount of workpieces on the same production line, which can contribute to improvement in productivity of the production line. In addition, it is processed in the processing process
History information displayed in each processing step until
History information is added by deleting when it becomes
Where necessary for the product
And can be processed.

[Brief description of the drawings]

FIG. 1 is a schematic layout diagram of a production line showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a specific example of a workpiece.

FIG. 3 is an explanatory diagram showing a specific example of history information.

FIG. 4 is an explanatory diagram showing another specific example of history information.

[Description of Signs] 10 Workpiece 20 Processing step / history entry section 30 Information acquisition section 40 Central processing unit 50 Transport path

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-92606 (JP, A) JP-A-58-50750 (JP, A) JP-A-4-73925 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/02

Claims (1)

(57) [Claims] In 1. A production line comprising a plurality of processing steps, performed different processing by the workpiece, when the continuous production of products of many kinds, manages the processing steps on each of said workpiece a method, wherein along with previously expressed an identification code for each workpiece, each time the workpiece is subjected to machining in each machining step, wherein the history information in the processing step <br/> Notation on the workpiece and notation in each processing step up to that time
A method for managing processing steps in a multi-product line , wherein deleted history information is deleted when it is no longer necessary .