JP2004118472A - Production scheduling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of the delay of delivery time in an intermediate parts stock reserving system. <P>SOLUTION: This production process scheduling device is provided with a means for selecting intermediate parts fulfilling the request specifications of customers from a stock based on order reception information, and for reserving the intermediate parts to the customers, a means for determining whether or not the customer-reserved intermediate parts fulfill customer specifications from the inspection results, a means for determining the reserved conditions of products from the customer reservation results and the determination results, and a means for allocating loads from the customer reservation date or the latest process result date to the forward direction of the necessary production processes concerning the production plan of the customer-reserved products, and for allocating loads from the term of delivery to the reverse direction of the necessary production processes concerning the production plan of customer-unreserved products. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a production scheduling technique.
[0002]
[Prior art]
The customer allocation method based on an order can be broadly classified into the following three types depending on the form of the production method of the product to be ordered. The first is a provision for finished goods inventory, which is often used for products for which the order-receiving product is a make-to-stock product. The second is provision for intermediate parts inventory. The third is raw material inventory reserve, which is often used for products for which orders are made individually.
[0003]
In recent years, high-mix low-volume production has become mainstream, and the period from order receipt to delivery has become shorter. For this reason, the second intermediate part inventory allocation is frequently performed. Intermediate parts inventory allocation is to produce parts that are common to many products as intermediate products, and then make customer allocations based on orders received, process and assemble according to the process flow based on customer standards and specifications, Final product. Intermediate parts inventory provision has the advantage of eliminating unnecessary work-in-progress because it produces only what the customer needs, and is performed regardless of the type of product, such as an assembly or process product. In the intermediate stock allocation method, it is important to produce a product on a production schedule so as to meet a delivery date specified by a customer.
[0004]
A conventional process product inventory allocation system will be specifically described by taking a semiconductor wafer production management system as an example. Some characteristics of semiconductor wafers are inspected after crystal growth to understand the crystal characteristics of the lot. Based on the result of the characteristic inspection, the customer is allocated according to the use of the product, and the slicing process and the polishing process are performed based on the customer standards and specifications, and then shipped. In other words, this is an intermediate inventory customer allocation system in which production is performed up to the crystal growth process and allocation is performed with an intermediate inventory (for example, see Patent Documents 1, 2, and 3).
[0005]
On the other hand, many technologies have already been disclosed for production scheduling. It discloses a production process scheduler having a function of assigning priorities according to the total required time required for a series of production processes for each lot at the time of scheduling and allocating to a scheduled line table. (For example, see Patent Document 4). In addition, production scheduling having a function of simply assigning a load to an order according to the delivery date, adjusting the load manually, and rescheduling by changing the lead time for each order when the delivery date is delayed. Some devices disclose a device (for example, see Patent Document 5).
[0006]
Further, many production scheduling techniques in which process development techniques are mixed are disclosed. As one of them, there is a method in which a process plan is determined by backward scheduling according to a process sequence, and forward scheduling is executed when a manufacturing time comes (for example, see Patent Document 6). In addition, the input data, which is the unit of production, is arranged in the order of completion schedule, and the backward simulation assigns loads retroactively to the production process from the scheduled completion date, and the forward simulation allocates the load in the forward direction of the production process from the scheduled input date. There is also disclosed a manufacturing management system in which a simulation and a simulation are executed as a pair, and the difference between the results of the two simulations is evaluated to adjust the arrangement of the input data and repeat the simulation (for example, Patent Document 7). reference).
[0007]
In addition, a factory scheduler that can respond to irregularities in the production process by scheduling using a time value called the in-process instruction lead time, which is a sum of the net lead time, which is the total processing time for scheduling of each equipment, and a fixed margin time And a scheduler support system are disclosed (for example, see Patent Document 8). In this patent document 8, the allowance time is set as a constant value for each lot as data, or manually input.
[0008]
[Patent Document 1]
JP-A-9-300179 [Patent Document 2]
JP-A-11-353393 [Patent Document 3]
JP-A-11-345750 [Patent Document 4]
JP-A-5-324664 [Patent Document 5]
Japanese Patent Application Laid-Open No. 7-141435 [Patent Document 6]
JP-A-3-149162 [Patent Document 7]
JP-A-8-314526 [Patent Document 8]
JP-A-8-215994
[Problems to be solved by the invention]
Despite the provision of intermediate parts inventory, in the inspection process after customer allocation, a lot that meets the required customer standard may not be completed. In this case, as a general countermeasure, a method of reallocating the customer to the intermediate part inventory, a method of re-working by repeating the same process, and a method of performing the work in an additional process to compensate for a characteristic that is out of the standard Can be considered.
[0010]
However, as a result, more work time is required than a preset production plan, thereby causing an overall work delay. In the conventional make-to-stock production system, it was possible to deal with irregular factors such as defects by keeping product inventory with a margin of safety. However, in the method for allocating intermediate parts to be produced in accordance with the specifications and the delivery date specified by the customer, if a work delay occurs due to a defect, there is a possibility that the delivery date is directly delayed, which causes a serious problem. Therefore, in the production scheduling in the intermediate parts inventory allocation method, it is necessary to perform processing in consideration of defects after customer allocation.
[0011]
In Patent Documents 1 to 3 described in the related art, no consideration is given to changing the production scheduling when a defect occurs after customer allocation.
[0012]
In addition, the above-mentioned problems have not been solved even in the related art relating to production scheduling. For example, when a plan delay occurs, there are an automatic scheduling method based on the priority of Patent Document 4 and a method of changing the lead time for each order of Patent Document 5 to perform scheduling. All of these methods deal with defects after customer allocation. is not. In addition, since the parameters are manually adjusted in any case, it is not practical for production scheduling of a product such as a semiconductor wafer which is a multi-product small-quantity production.
[0013]
As described in Patent Literature 6 and Patent Literature 7, the use of two types of process development methods, forward and backward, improves the accuracy of the production plan, but also does not consider the defects after customer allocation. .
[0014]
Also, as in Patent Document 8, irregular processing can be handled by considering a margin time, but the lead time from the start of work in the first step to the completion of work in the last step tends to be long, so that the delivery time is short. It is not suitable for order-made production, which is required to be customized.
[0015]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to solve a problem relating to a defect after customer allocation. That is, the object is to suppress the occurrence of a delivery delay by scheduling the production in consideration of the occurrence of defects in the production process in the custom production system.
[0016]
[Means for Solving the Problems]
In order to solve this problem, the present invention provides a production scheduling apparatus that allocates a customer to an ordered product at a stage of an intermediate part. Customer allocation means to allocate to
Inspection result determining means for determining whether or not the customer-allocated intermediate part satisfies the customer standard from the inspection result; allocation status determining means for determining the allocation state of the intermediate part from the customer allocation means and the inspection result determining means; The process of assigning the load of the work process in the forward direction of the production process from the customer allocation date or the latest process actual date for the planned production plan, and the process of assigning the load of the work process in the reverse direction of the production process from the delivery date for the production plan with no customer allocation It has a capability allocation means.
[0017]
With this device, the rescheduling of the work delay due to the occurrence of defective products enables highly accurate calculation of the scheduled work completion date, and can create a production plan in which the delivery deadline is prevented.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a semiconductor wafer manufacturing process according to an embodiment of the present invention.
In FIG. 1, a crystal growth step (101) of growing a crystal of an ingot in prospective production and a characteristic evaluation of the ingot (102) are performed by using characteristics such as specific resistance as a growth condition, and an ingot inventory (103) is obtained. The ingots in the ingot stock are classified according to size and characteristics, and are intermediate products that can be allocated to a plurality of customers. The ingot is allocated to the customer from the stock (104), and is subjected to a post-process of finishing the product according to the standard of the customer, and becomes a semiconductor wafer. To allocate and ship semiconductor wafers in ingot units to customers, this is defined as one lot. The post-processing includes a slicing step (105) for cutting the ingot into wafers, an evaluation step (106) for evaluating the characteristics of the semiconductor wafer, and a polishing step (107) when the evaluated lot conforms to the customer's standard. Mirror-polished and shipped (108).
[0019]
However, if the lot does not satisfy the customer's standard from the result of the evaluation step (106), the customer is reallocated (104) from the ingot stock (103) and the slice (105) is reworked. In this case, a lot that no longer satisfies the customer's standard is stored in the wafer stock (107), and if it conforms to another customer's standard, customer allocation (110) is performed, polishing (107), and shipment (108). ).
Further, from the result of the evaluation step (106), there is a case where the lot does not satisfy the customer's standard, but the customer's standard is satisfied by additionally performing the lapping step (111) which is another process.
[0020]
FIG. 2 is a block diagram showing the elementary features of the production scheduling device according to the present invention.
As shown in the figure, the production scheduling device of the present embodiment includes a keyboard and a CRT, and includes an acquisition unit (210) for inputting and outputting information, a storage unit (230) for storing information used for production management, A processing unit (220);
[0021]
The processing unit (220) selects an intermediate part that satisfies the customer's required standard from the inventory based on the order information and allocates it to the customer, and a customer standard based on the inspection result of the intermediate part allocated to the customer. Inspection result determination means (222), customer allocation means (221) and inspection result determination means (222) for determining whether or not they are satisfied determine the state of the production plan related to the order information and determine the priority of each production plan. Assigning the production plan to the capacity of each process or each unit of equipment by switching the lot state determination means (223) and the method of creating a production plan of a process from the state of each production plan created by the lot state determination means (223) And a production instructing means (225) for outputting a production instruction from the process capacity allocating means (224) to each process.
[0022]
The storage unit (230) includes an order information DB for registering order information from customers, an inventory information DB for registering inventory information for each ingot and wafer, and a process information DB for registering in-process information for each ingot and wafer. , An inspection information DB for registering inspection information for each ingot and wafer, a production plan information DB for registering production plan information for each ingot and wafer, and a customer allocation information DB for registering customer allocation information.
[0023]
FIG. 3 shows an example of the registered contents of the order information DB.
As shown in the figure, each record registered in the order information DB includes a field for registering an order number, a field for identifying a customer name, a field for registering a delivery date, a field for registering a requested quantity, and a request for a customer. A field for registering a standard (specific resistance, wafer thickness) and a field for a process master which is information for identifying which data of a process master DB for registering a process to be used are used.
[0024]
FIG. 4 shows an example of the inspection information DB.
As shown in the drawing, each record of the inspection information DB includes a field of a lot number which is an identification number of an intermediate part, a field of registering information of an inspection result (resistivity), and a field of registering an inspection result of a wafer thickness. I have. In FIG. 4, specific resistance is taken as an example, but the same applies to other characteristic information and shape information, and inspection information including a plurality of components may be used.
[0025]
FIG. 5 shows an example of the customer allocation information DB.
The customer allocation information DB includes an order number, a branch number, a lot number, a quantity, and a lot state. When the required quantity of the order NO in FIG. 3 is not satisfied by one ingot (corresponding to the lot NO), a plurality of lots are allocated to the order NO. A branch number of the order number is assigned to the allocated unit (ingot unit). The lot state will be described in detail in the description of FIG. 10 and FIG.
[0026]
FIG. 6 shows an example of the production plan information DB.
The production plan information DB includes an order number, a branch number, a process number, a process name, and a scheduled completion date. The process number is the order of working a certain lot (order number-branch number).
[0027]
FIG. 7 shows an example of the production capacity master information DB.
The production capacity master information DB includes a process name, a facility number, and the number of processed sheets. The processing time indicates the equipment processing time per wafer.
[0028]
FIG. 8 shows an example of the process master information DB.
The process master information DB includes a process master, a process number, and a process name.
[0029]
The production scheduling device having the above configuration includes, for example, an external storage device such as a CPU, a memory, and a hard disk device, and a device that reads data from a portable storage medium such as a CD-ROM or a DVD-ROM, as shown in FIG. It has a general configuration including an input device such as a keyboard and a mouse, a communication device that communicates with an output device such as a CRT and an LCD via a network such as the Internet, and a bus connecting these devices. It can be constructed on a computer system or a network system provided with a plurality of such computer systems.
[0030]
FIG. 10 shows an operation flow of the production scheduling method of the present invention.
A description will be given according to the following operation flow.
First, the lot state is determined. The lot state indicates the relationship between the order data and the allocation of the intermediate parts in stages.
[0031]
FIG. 11 is a diagram for explaining a lot state showing the relationship between the order data and the allocation of intermediate parts in stages. The lot state 0 is a state in which it is not determined to which intermediate part to allocate at the stage before the intermediate part is allocated to the order. In this state, the work process is temporarily determined and may be replaced by the inspection result. Next, the lot state 1 is a state in which, although an intermediate part is allocated to an order, the allocation relationship may be canceled depending on the inspection result and another intermediate part may be allocated. Even in the lot state 1, the work process is temporarily determined, and may be replaced by the inspection result. Finally, lot state 2 indicates a state in which an intermediate part has been allocated to the order, and this relationship has been determined. In the lot state 2, the work process is also determined. In the present embodiment, the above three lot states are defined in the semiconductor wafer manufacturing process shown in FIG. 1, but more lot states can be defined.
[0032]
The determination of the lot state is performed by the lot state determination means in FIG. First, when new order data is first received, the lot status of all lots is zero. After confirming the allocated lot, the lot status is changed from 0 to 1. Confirmation of the allocation is performed by the allocation information. Also, a lot state is determined from the result of the evaluation determination. If the result of the evaluation judgment is OK, the lot state is changed from 1 to 2. As a result of the evaluation determination, if the status is NG, the lot status is changed from 1 to 0. Lots whose lot status has become 0 need to be allocated again.
[0033]
Next, a process capability is generated. The process capability sets how many wafers can be worked per unit time in each work process. In this embodiment, a production capacity master is prepared.
[0034]
After generating the process capacity frame, the production plan of the lot in lot state 2 is sequentially developed (forward developed) from the actual date of the evaluation process to the subsequent work, and the production plan is assigned to the previously created process capacity frame. Go. If the capacity of the process on the day is exceeded, it will be allocated the next day. Also, at this time, there is a case where additional work is required as a result of the evaluation process determination. Therefore, when creating a production plan, the process development is performed using the work process master designated by the evaluation determination result.
[0035]
Next, the production plan of the lot in lot state 1 is sequentially developed (forward developed) from the allocation date to the subsequent work, and the production plan is allocated to the process capacity frame created earlier. If the capacity of the process on the day is exceeded, it will be allocated the next day.
[0036]
Finally, the production plan of the lot in lot state 0 is sequentially developed (backward developed) from the shipping date to the previous work, and the production plan is allocated to the previously created process capacity frame. If the capacity of the process on the day is exceeded, it will be allocated the day before. This is the end of the operation flow.
[0037]
FIG. 12 summarizes the process development method for each lot state. In this method, the scheduled shipping date is determined for each lot allocation status, the process is developed, and the load is allocated. For an unallocated lot (lot status 0), the allocation instruction scheduled date is determined by performing backward development in the order of each work process from the scheduled shipping date determined at the time of receiving the order. Next, for a lot for which allocation has been instructed (lot state 1), a lot is automatically generated in accordance with the actual number of allocation instructions, and forward-developed based on the actual date of allocation instructions to determine a scheduled shipping date. If the ingot becomes defective as a result of the characteristic evaluation after the slicing process, a production instruction is issued to the slicing process by releasing the allocation. Similarly to the allocation instruction, for the lot of evaluation evaluation OK (lot state 2), a lot is automatically generated in accordance with the actual number of allocations, forward-developed based on the evaluation determination date, and the scheduled shipping date is finalized. decide.
[0038]
FIG. 13 specifically shows an example of a Gantt chart screen when the process is developed. First,
(1) In the unallocated state (lot state 0), backward development is performed with the delivery date (2/26) as the scheduled shipping date, based on the scheduled shipping date. In the Gantt chart, each process is displayed in a different color.
(2) A lot is automatically generated in response to the work result of 150 sheets in the allocation instruction process. At this time, the plan of 400 sheets is divided into 250 unallocated lots and 150 allocated lots. At the same time, forward development is performed based on the actual slice instruction date (2/8). In this example, it can be seen that the scheduled shipping date 2/28 is two days behind the delivery date 2/26. Therefore,
(3) Modify the plan to meet the delivery date. In this case, the scheduled slicing completion date changes from 2/15 to 2/13.
(4) When the allocation result is input, a lot is automatically generated, and forward development is performed based on the allocation result date. In this case, the scheduled shipping date is 2/20, which is earlier than the initial plan. Also, if the lot becomes defective during the process,
(5) The allocation is released, and a production instruction is given to the slice instruction. In the screen example, the plan of 150 sheets for which slicing has been instructed is added to the plan of 250 sheets in the unallocated state, resulting in a plan of 400 sheets, and production is instructed to the slicing instruction process. If the delivery date has been delayed, the scheduled slice instruction completion date (2/5) is adjusted.
[0039]
FIG. 14 shows a screen example of the process load mountain crush according to the allocation state.
From this screen, it can be seen that a low priority unallocated lot is allocated later, and a high priority allocated lot is allocated first. It can also be seen that unallocated lots have been moved and leveled to fit within the process capability.
[0040]
The customer allocation processing means will be described with reference to FIG.
First, the inspection information of the lot for which the evaluation process of the previous process has been completed is obtained (1501). Next, one record of target order information is acquired from the order information (1502). At this time, the target order information is all the back-order information at this time. However, if items other than the evaluation items, such as size and product name, clearly deviate from the allocation conditions, they are not applicable at this point. The characteristic range of the acquired order data is acquired from the customer standard information (1503). The number of acquired sheets is calculated using the characteristic range of the customer standard information, the wafer number, and the inspection information (1504). However, in the case of a semiconductor wafer, since only a few samples of the wafer have characteristic results at this point, the converted number is used as the number of acquired wafers. When the processing is completed for all target order data (1506), the result is registered in the customer allocation information file (1507).
[0041]
The inspection result determination means will be described with reference to FIG.
First, the inspection information of the lot for which the evaluation process has been completed is obtained. Next, the characteristic range of the assigned customer is acquired from the customer standard information. Using the characteristic range of the customer standard information, the wafer number and the inspection information, it is determined whether the standard is satisfied. If the determination result is OK, it is determined whether there is any change in the work process. This determination method is performed by inputting data during the evaluation process. If there is no change, the lot status is changed from 1 to 2, and the process ends. If there is a change, change the work process master to be referenced at the time of production planning, and end the process. If the evaluation judgment is NG, the lot state is set to 0, and the process is terminated.
[0042]
The production instruction means will be described with reference to FIG.
The production instructing means is a method of giving a production instruction to the slicing step preferentially for a lot whose lot status has changed from 1 to 0 by the inspection result determining means. Specifically, in the evaluation step, the lot status of the customer allocation information DB is updated from 1 to 0 by the production scheduler device using the inspection result determination means described in FIG. 16 based on the input inspection information. With respect to the lot, the allocation processing means performs the allocation processing for the lot, and uses the network for the slicing process to instruct a work start. According to this method, a lot in the case where a work delay occurs in the intermediate inspection can be preferentially instructed to the process.
[0043]
The delivery date reply function will be described with reference to FIG.
First, register customer information. As the customer information, the provisional order number, customer name, customer standard, number of requests, and delivery date are input. Next, it is confirmed whether or not there is a target intermediate part in the intermediate stock. In some cases, a lot, which is a unit of the production plan, is generated, and backward development is performed from the delivery date. If the scheduled start date is today or later, a reply is made with the delivery date entered initially. If the scheduled start date is before today, it will be forward developed from today, and the delivery date will be returned as the delivery date. If there is no stock, register when the stock is available. Next, forward development is performed from the stock registration date, and the delivery date is returned as the delivery date.
[0044]
【The invention's effect】
As described above, the production scheduling apparatus of the present invention changes the scheduling method for the lot allocation state and allocates a plan to a process in order to consider the occurrence of defects after customer allocation. As a result, a highly accurate production plan can be realized, and short delivery times and delivery times that are required by customers can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a process flow of a production line to be processed.
FIG. 2 is a block diagram showing components that are one embodiment of the present invention.
FIG. 3 is a diagram showing an order information DB as one embodiment of the present invention.
FIG. 4 is a diagram showing an inspection information DB as one embodiment of the present invention.
FIG. 5 is a diagram showing a customer allocation information DB as one embodiment of the present invention.
FIG. 6 is a diagram showing a production plan information DB as one embodiment of the present invention.
FIG. 7 is a diagram showing a production capacity master information DB as one embodiment of the present invention.
FIG. 8 is a diagram showing a process master information DB as one embodiment of the present invention.
FIG. 9 is a diagram illustrating a hardware configuration of a production scheduling apparatus according to an embodiment of the present invention.
FIG. 10 is a diagram showing an operation flow of a production scheduling device as one embodiment of the present invention.
FIG. 11 is a diagram defining a lot state, which is one embodiment of the present invention.
FIG. 12 is a diagram showing a lot state-based process development method as one embodiment of the present invention.
FIG. 13 is a Gantt chart showing a process development method for each lot state according to an embodiment of the present invention.
FIG. 14 is a diagram showing a screen example of a process load stacking for each lot state, which is one embodiment of the present invention.
FIG. 15 is a diagram showing an operation flow of a customer allocation means which is one embodiment of the present invention.
FIG. 16 is a diagram showing an operation flow of a test information registration unit which is an embodiment of the present invention.
FIG. 17 is a diagram showing an operation flow of a production instruction unit which is one embodiment of the present invention.
FIG. 18 is a diagram showing an operation flow of a delivery date answering unit which is an embodiment of the present invention.
[Explanation of symbols]
210 Input / output unit 220 Processing unit 221 Customer allocation unit 222 Inspection result determination unit 223 Lot state determination unit 224 Process capability allocation unit 225 Production instruction unit 226 Delivery date response unit 230 Storage unit

Claims (6)

A production scheduling device for scheduling a work process for producing a product,
Customer allocation means for performing customer allocation for associating the order information with the intermediate part based on order information from a customer at the stage of the product being an intermediate part;
Inspection result determination means for inspecting the intermediate part allocated to the customer and determining from the inspection result whether the intermediate part satisfies the standard required by the customer,
Allocation state determination means for determining an allocation state of the intermediate component from a determination result in the inspection result determination means,
Based on the allocation status determined by the allocation status determination means, for the intermediate product for which the customer allocation has been performed, a process capability allocation for allocating the load of the work process from the customer allocation date or the latest process actual date in the forward direction of the production process. A production scheduling device comprising means. The production scheduling device according to claim 1,
The production scheduling apparatus, wherein the process capability allocating means allocates the load of the work process from the delivery date to the reverse direction of the production process for the intermediate product not yet allocated to the customer. The production scheduling device according to claim 1, wherein:
When the allocation state in the allocation state determination unit changes from the result of the determination in the inspection result determination unit and a work process is added,
The process capability allocating means registers the added work process as a work master, and allocates the load of the added work process in the forward direction of the production process from the actual process date using the work master. Production scheduling equipment. The production scheduling device according to any one of claims 1 to 3, wherein
According to the determination result of the inspection result determination means, if the intermediate part allocated to the customer does not satisfy the standard required by the customer,
The production scheduling device, wherein the customer allocation means includes production instruction means for reallocating intermediate parts to the customer and instructing production. The production scheduling device according to any one of claims 1 to 4,
The production scheduling device, wherein the process capability allocating means obtains a delivery date in response to a request from a customer before an order is received, by allocating a load of a work process from a scheduled delivery date in a direction opposite to a production process. The production scheduling device according to any one of claims 1 to 5,
A production scheduling apparatus, comprising: display means for displaying, on the display means, a screen showing a Gantt chart and a screen showing a load of a work process for each state of an intermediate part.

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