JP3965348B2 - Production scheduling device - Google Patents

Description

[0001]
BACKGROUND 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 roughly divided into the following three types depending on the form of the production method of the product to be ordered. The first is provision for finished product inventory, which is often used for products for which the order target product is a prospective product. The second is provision for intermediate parts inventory. The third is the provision of raw material inventory, which is often used for products for which the order target product is individual production.
[0003]
In recent years, low-volume production of many kinds has become mainstream, and the period from order receipt to delivery has become shorter. For this reason, a lot of provision for the second intermediate part inventory is made. Interim parts inventory reserve is the prospective production of parts common to many products as intermediate products, after which customer provisions are made based on orders received, processed and assembled according to the process flow based on customer standards and specifications, Final product. The provision of intermediate parts inventory has the advantage that there is no useless in-process inventory because only what the customer needs is produced, and it is performed regardless of product types such as assembly products and process products. In the intermediate inventory allocation method, it is important to produce with a production schedule in time for the delivery date specified by the customer.
[0004]
A conventional process product inventory allocation method will be specifically described by taking a semiconductor wafer production management method as an example. Semiconductor wafers are inspected for several characteristics in order to grasp the crystal characteristics of the lot after crystal growth. Based on the results of this characteristic inspection, the customer is allocated in accordance with the use of the product, and then the slicing process and polishing process are performed based on the customer standards and specifications before shipment. In other words, it is an intermediate inventory customer allocation method in which production up to the crystal growth process is anticipated and allocation is performed with intermediate inventory (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
[0005]
On the other hand, many techniques have already been disclosed for production scheduling. Discloses a production process scheduler that has the function of assigning priorities according to the length of the total time required for a series of production processes for each lot, and allocating them to the schedule table when scheduling. (For example, refer to Patent Document 4). Also, production scheduling that has the function of rescheduling by changing the lead time for each order when the load is manually adjusted after manual load allocation according to the delivery date and there is a delay in delivery Some have disclosed an apparatus (for example, see Patent Document 5).
[0006]
In addition, many production scheduling techniques in which process development methods are mixed are disclosed. As one of them, a process plan is determined by backward scheduling in accordance with the process order, and forward scheduling is executed at the time when the production time comes (see, for example, Patent Document 6). In addition, backward simulation that arranges input data, which is a production unit, in the order of completion, assigns loads retroactively from the scheduled completion date, and forward that assigns loads in the forward direction of the production process from the scheduled input date. There is also a manufacturing management system that executes simulations in pairs, evaluates the difference between the results of both simulations, adjusts the arrangement of input data again, and repeats the simulation (for example, Patent Document 7). reference).
[0007]
Also, a factory scheduler that can handle irregularities in production processes by scheduling using a time value called in-process instruction lead time, which is a sum of net lead time, which is the total processing time for scheduling of each equipment, plus a certain margin time And a scheduler support system is disclosed (for example, see Patent Document 8). In Patent Document 8, the margin time is set as a constant value for each lot as data, or manually input.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-300179 [Patent Document 2]
Japanese Patent Laid-Open No. 11-353393 [Patent Document 3]
Japanese Patent Laid-Open No. 11-345750 [Patent Document 4]
JP-A-5-324664 [Patent Document 5]
JP-A-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]
Although the intermediate parts inventory has been allocated, the inspection process after the customer allocation may not complete a lot that satisfies the required customer specifications. As a general countermeasure in this case, a method of reallocating this customer to the intermediate parts inventory, a method of re-working the same process repeatedly, and a method of working in an additional process to compensate for characteristics that are out of specification Can be considered.
[0010]
However, as a result, it takes more work time than a preset production plan, thereby causing an overall work delay. In the conventional prospective production method, it was possible to cope with irregular factors such as defects by having a product inventory with a safety margin. However, according to the standard and delivery date specified by the customer, in the intermediate part inventory allocation method to be produced, if a work delay occurs due to a defect, there is a possibility that a delay in the delivery date may occur directly, resulting in a serious problem. Therefore, in production scheduling in the intermediate parts inventory allocation method, processing that takes into account defects after customer allocation is necessary.
[0011]
In Patent Documents 1 to 3 described in the prior art, no consideration is given to changing production scheduling when a defect occurs after customer allocation.
[0012]
In addition, the above-mentioned problem is not 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 scheduling when changing the lead time for each order of Patent Document 5, both of which are methods for dealing with defects after customer provisioning is not. In addition, since the parameters are manually adjusted, it is not practical for production scheduling of products such as semiconductor wafers that are produced in a variety of products in small quantities.
[0013]
The accuracy of production planning is improved by using two types of process development methods, forward and backward, as in Patent Document 6 and Patent Document 7, but these are not considered for defects after customer provisioning. .
[0014]
In addition, as in Patent Document 8, it is possible to cope with irregular processing by considering the allowance time, but since the lead time from the start of the first process to the completion of the final process tends to be long, the delivery time is short. It is not suitable for individual order production that needs to be made.
[0015]
The present invention has been made to solve the above-described problems, and an object of the present invention is to solve problems related to defects after customer provisioning. In other words, the purpose is to suppress the delay in delivery by scheduling production in consideration of the occurrence of defects in the production process in the order production system.
[0016]
[Means for Solving the Problems]
In order to solve this problem, the present invention is a production scheduling apparatus that schedules a work process for producing a process product by an intermediate part inventory allocation method, in which an intermediate part manufactured from a material has a size and characteristics. A customer who searches the inventory information database based on the order information received from the customer and the stock information database registered together with the information of the customer, and allocates the intermediate part of the required lot satisfying at least the customer requirement standard in the order information to the customer An allocation means, and inspecting the size and characteristics of the intermediate part formed by processing in the course of manufacturing the intermediate part allocated to the customer, and determining from the inspection result whether the intermediate part satisfies a standard required by the customer The customer result is allocated according to the inspection result determination means and the determination result of the inspection result determination means. If the part does not satisfy the standard required by the customer, the production instruction means for issuing an instruction for allocating the intermediate part to the customer again to the customer allocating means, and issuing the production instruction for the customer allocated intermediate part; and the inspection Based on the determination result in the result determination unit, the lot state determination unit that determines the allocation state of the intermediate part, and the intermediate product that has performed the customer allocation based on the allocation state determined in the lot state determination unit, The load is allocated in the forward direction of the production process from the date of customer allocation or the latest process performance date, and for intermediate products that are not allocated to the customer, the load of the work process is allocated in the reverse direction of the production process from the delivery date, and the inspection result determination means If the allocation status in the lot status determination means is changed and the work process is added from the result of the determination in, the added work process is A production scheduling apparatus comprising: process capability allocating means for performing a process of allocating a load of the added work process in the forward direction of the production process from the process performance date using the work master while registering as a star Has proposed.
[0017]
With this device, it is possible to calculate work completion scheduled dates with high accuracy by rescheduling work delays due to the occurrence of defective products, and to create production plans that prevent delays in delivery.
[0018]
DETAILED DESCRIPTION OF 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, using a characteristic such as specific resistance as a growth condition, a crystal growth step (101) for crystal growth of an ingot by prospective production, and a characteristic evaluation (102) of the ingot are performed to obtain an ingot inventory (103). Ingots in the ingot inventory are classified according to size and characteristics, and are intermediate products that can be allocated to multiple customers. The ingot allocates a customer from the inventory (104), and performs a post-process that finishes in accordance with the customer's specifications to become a semiconductor wafer. In order to allocate and ship ingot unit semiconductor wafers to customers, this is defined as one lot. Subsequent steps include 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) if the evaluated lot conforms to the customer's standards. Mirror finish and ship (108).
[0019]
However, if the lot does not satisfy the customer's standard from the result of the evaluation process (106), the customer is again allocated from the ingot stock (103) (104) and sliced (105). In this case, the lot that does not satisfy the customer's standard is stored in the wafer inventory (107), and if it conforms to another customer's standard, the customer is allocated (110), polished (107), and shipped (108). )
Further, from the result of the evaluation process (106), the lot may not satisfy the customer's standard, but the customer's standard may be satisfied by additionally performing a lapping process (111) which is a separate process.
[0020]
FIG. 2 is a block diagram showing the elemental features of the production scheduling apparatus according to the present invention.
As shown in the figure, the production scheduling apparatus of the present embodiment is composed of a keyboard and a CRT, and an obtaining power unit (210) that inputs and outputs information, a storage unit (230) that stores information used for production management, It has a processing unit (220).
[0021]
The processing unit (220) selects an intermediate part satisfying the customer's required standard from the stock based on the order information and allocates it to the customer, and determines the customer standard from the inspection result of the intermediate part allocated to the customer. The status of the production plan related to the order information is determined from the inspection result determination means (222) for determining whether it is satisfied, the customer allocation means (221), and the inspection result determination means (222), and the priority of each production plan is determined. The method of creating a production plan for a process is switched from the state of each production plan created by the lot status judging means (223) and the lot status judging means (223), and the production plan is assigned to the capacity of each process or each equipment unit. Process capability assigning means (224) capable of performing the above and production instruction means (225) for outputting a production instruction from the process capability assigning 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 ingots and wafers, and an in-process information DB for registering in-process information for ingots and wafers. , An inspection information DB for registering inspection information for each of the ingot and the wafer, a production plan information DB for registering production plan information for each of the ingot and the wafer, and a customer provisioning information DB for registering customer provisioning information.
[0023]
FIG. 3 shows an example of registered contents in 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 customer request. It has a field for registering standards (specific resistance, wafer thickness) and a process master field that is information for identifying which data in the process master DB that registers the process to be 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 lot number which is an identification number of an intermediate part, a field for registering inspection result (specific resistance) information, and a field for registering an inspection result of wafer thickness. Yes. In FIG. 4, specific resistance is taken as an example, but the same applies to other characteristic information and shape information, and inspection information consisting of 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, branch number, lot number, quantity, and lot status. When the requested 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 for the order NO. The 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 FIGS.
[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. Process NO is the order in which a certain lot (order received—branch number) is worked.
[0027]
FIG. 7 shows an example of the production capacity master information DB.
The production capacity master information DB is composed of a process name, equipment 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 NO, and a process name.
[0029]
The production scheduling apparatus configured as described above includes, for example, a CPU, a memory, an external storage device such as a hard disk device, and a device that reads data from a portable storage medium such as a CD-ROM or DVD-ROM as shown in FIG. It has a general configuration with an input device such as a keyboard and mouse, a communication device that communicates with an output device such as a CRT or LCD via a network such as the Internet, and a bus that connects these devices. It can be constructed on a computer system or a network system including a plurality of computer systems.
[0030]
FIG. 10 shows an operation flow of the production scheduling method of the present invention.
The operation will be described according to the following operation flow.
First, the lot state is determined. The lot state indicates the relationship between order data and provision of intermediate parts in stages.
[0031]
FIG. 11 is a diagram for explaining the lot state showing the relationship between the order data and the provision of intermediate parts in stages. The lot state 0 is a state in which an intermediate part to be allocated is not yet determined at the stage before the intermediate part is allocated for an order. In this state, the work process is temporarily determined and may be replaced with the inspection result. Next, the lot state 1 is a state in which an intermediate part is allocated for an order received, but the allocation relationship may be canceled and another intermediate part may be allocated depending on the inspection result. Even in the lot state 1, the work process is temporarily determined and may be replaced with the inspection result. Lastly, the lot state 2 indicates a state in which intermediate parts are reserved for the received order and this relationship is established. In the lot state 2, the work process is also confirmed. In the present embodiment, in the semiconductor wafer manufacturing process shown in FIG. 1, the above three lot states are defined, but more lot states can be defined.
[0032]
The lot state determination is performed by the lot state determination unit shown in FIG. First, when new order data is received for the first time, the lot status of all lots is zero. If the allocated lot is confirmed, the lot state is changed from 0 to 1. Whether or not the allocation has been made is confirmed by the allocation information. In addition, the lot state is determined from the result of the evaluation determination. As a result of the evaluation determination, the lot state is changed from 1 to 2 in the case of OK. As a result of the evaluation determination, the lot state is changed from 1 to 0 in the case of NG. Lots whose lot state has become 0 must be allocated again.
[0033]
Next, process capability is generated. The process capability is set for 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 capability frame, the production plan for the lot in lot state 2 is sequentially expanded from the actual date of the evaluation process to the subsequent work (forward expansion), and the production plan is assigned to the previously created process capability frame Go. If the capacity of the process on the day is exceeded, it will be allocated the next day. At this time, there may be additional work as a result of the determination of the evaluation process. Therefore, when creating a production plan, the process development is performed using the work process master indicated by the evaluation determination result.
[0035]
Next, the production plan of the lot in the lot state 1 is sequentially developed (forward development) from the allocation date toward the subsequent work, and the production plan is assigned to the previously created process capability frame. If the capacity of the process on the day is exceeded, it will be allocated the next day.
[0036]
Lastly, the production plan of the lot in the lot state 0 is sequentially developed (backward development) from the date of shipment toward the previous work, and the production plan is assigned to the previously created process capacity frame. If the process capacity of the day is exceeded, it will be allocated the day before. This completes 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 state, the process is expanded, and the load is allocated. For an unallocated lot (lot state 0), the allocation instruction scheduled date is determined by developing backwards in the order of each work process from the scheduled shipping date determined at the time of ordering. Next, for a lot for which allocation has been instructed (lot state 1), a lot is automatically generated in accordance with the allocation instruction actual number of sheets, forwardly expanded based on the allocation instruction actual date, and a scheduled shipping date is determined. Further, if the ingot becomes defective as a result of the characteristic evaluation after the slicing process, the production instruction is given to the slicing process by releasing the allocation. As with the allocation instruction, for lots with evaluation evaluation OK (lot state 2), lots are automatically generated according to the actual number of allocations, forwarded based on the evaluation determination date, and finally scheduled for shipment decide.
[0038]
FIG. 13 specifically shows an example of a Gantt chart screen during process development. First,
(1) In the unallocated state (lot state 0), the delivery date (2/26) is set as the planned shipping date, and backward development is performed based on the planned shipping date. In the Gantt chart, each process is displayed in a different color.
(2) A lot is automatically generated in response to 150 work results in the allocation instruction process. At this time, the 400-sheet plan is divided into 250 unallocated lots and 150 allocated lots. At the same time, forward deployment is based on the actual slice instruction date (2/8). In this example, it can be seen that the scheduled shipping date 2/28 is delayed by 2 days with respect to the delivery date 2/26. Therefore,
(3) Revise the plan in time for delivery. In this case, the scheduled slice completion date is changed from 2/15 to 2/13.
(4) When an allocation result is input, a lot is automatically generated, and forward development is performed based on the allocation actual date. In this case, the planned shipping date is 2/20, which is earlier than originally planned. Also, when a lot becomes defective during the process,
(5) The allocation is canceled and the production instruction is given to the slice instruction. In the screen example, 150 plans that have been instructed to slice are added to 250 plans that have not been allocated, resulting in a plan of 400 sheets, and production is instructed to the slice instruction process. If there is a delay in delivery, adjust the slicing instruction scheduled completion date (2/5).
[0039]
FIG. 14 shows a screen example of the process load collapse according to the allocation state.
From this screen, it can be seen that an unallocated lot with a low priority is allocated later, and an allocated lot with a high priority 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, inspection information of a lot for which the evaluation process of the previous process has been completed is acquired (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 remnant information at this point. However, if items other than the evaluation items such as size and product name clearly fall outside the provisioning conditions, they will be excluded from this point. The characteristic range of the order data acquired here 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 NO, and the inspection information (1504). However, in the case of a semiconductor wafer, since the wafer has a characteristic result of only a few samples at this time, the converted number is used as the obtained number. When processing for all target order data is completed (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, inspection information on a lot for which the evaluation process has been completed is acquired. Next, the characteristic range of the allocated customer is acquired from the customer standard information. Using the characteristic range of customer standard information, wafer NO, and 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 determined by inputting data during the evaluation process. If there is no change, the lot state is changed from 1 to 2, and the process ends. If there is a change, the work process master to be referred to at the time of production planning is changed and the process is terminated. If the evaluation determination is NG, the lot state is set to 0 and the process ends.
[0042]
The production instruction means will be described with reference to FIG.
The production instruction means is a method for preferentially instructing production to the slicing process for a lot whose lot state has changed from 1 to 0 by the inspection result determination means. Specifically, in the evaluation process, the lot state in the customer allocation information DB is updated from 1 to 0 using the inspection result determination means described in FIG. With respect to the lot, the allocation processing means performs allocation processing for the lot, and uses the network for the slicing process to give an instruction to start work. By this method, it is possible to preferentially instruct a process when a work delay occurs in the intermediate inspection.
[0043]
The delivery date reply function will be described with reference to FIG.
First, customer information is registered. As customer information, an order provisional NO, a customer name, a customer standard, the number of requests, and a delivery date are input. Next, it is confirmed whether there is a target intermediate part in the intermediate stock. In some cases, a lot, which is a unit of production plan, is generated and expanded backward from the delivery date. If the scheduled start date is after today, reply with the initial delivery date. If the planned start date is before today, forward deployment will start from today and the delivery date will be answered. If there is no stock, register when stock is available. Next, forward development is performed from the date of inventory registration, 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 assigns a plan to a process by changing the scheduling method for the lot allocation state in order to consider the occurrence of defects after customer allocation. Therefore, it is possible to realize a highly accurate production plan and to meet the short delivery times and delivery dates required by customers.
[Brief description of the drawings]
FIG. 1 is a diagram showing a process flow of a production line as a target.
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 which is an embodiment of the present invention.
FIG. 4 is a diagram showing an inspection information DB which is an embodiment of the present invention.
FIG. 5 is a diagram showing a customer allocation information DB which is an embodiment of the present invention.
FIG. 6 is a diagram showing a production plan information DB which is an embodiment of the present invention.
FIG. 7 is a diagram showing a production capacity master information DB which is an embodiment of the present invention.
FIG. 8 is a diagram showing a process master information DB which is an embodiment of the present invention.
FIG. 9 is a diagram showing a hard wafer configuration of a production scheduling apparatus which is an embodiment of the present invention.
FIG. 10 is a diagram showing an operation flow of a production scheduling apparatus which is an embodiment of the present invention.
FIG. 11 is a diagram defining a lot state which is an embodiment of the present invention.
FIG. 12 is a diagram showing a process development method for each lot state, which is an embodiment of the present invention.
FIG. 13 is a diagram showing, in a Gantt chart, a process development method for each lot state, which is an embodiment of the present invention.
FIG. 14 is a diagram showing an example of a process load accumulation screen for each lot state according to an embodiment of the present invention.
FIG. 15 is a diagram showing an operation flow of a customer allocation unit that is an embodiment of the present invention.
FIG. 16 is a diagram showing an operation flow of inspection information registration means which is an embodiment of the present invention.
FIG. 17 is a diagram showing an operation flow of production instruction means which is an embodiment of the present invention.
FIG. 18 is a diagram showing an operation flow of a delivery date answering means that is one 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 reply unit 230 Storage unit

Claims (2)

A production scheduling device that schedules a work process for producing a process product by an intermediate parts inventory allocation method ,
An inventory information database for registering intermediate parts manufactured from materials, along with size and characteristic information;
A customer provisioning means for searching the inventory information database based on order information from a customer and allocating to the customer an intermediate part of a required lot satisfying at least a customer requirement standard in the order information;
The customer provision and intermediate parts in the manufacturing process to inspect the size and characteristics of the intermediate part formed by machining, determines the inspection result from whether the test result intermediate component satisfies the standards which the customer requests determination Means,
According to the determination result of the inspection result determination means, if the intermediate part allocated for the customer does not meet the standard required by the customer, an instruction to allocate the intermediate part to the customer is issued again to the customer allocation means, and the customer is allocated. Production instruction means for issuing production instructions for intermediate parts;
Lot state determination means for determining the allocation state of the intermediate part from the determination result in the inspection result determination means;
Based on the allocation status determined by the lot status determination means, for the intermediate product that has allocated the customer, the workload of the work process is allocated in the forward direction of the production process from the customer allocation date or the latest process performance date,
For intermediate products that have not been allocated to customers, the work process load is allocated in the reverse direction from the delivery date to the production process, and
When the allocation state in the lot state determination unit is changed from the determination result in the inspection result determination unit and a work process is added, the added work process is registered as a work master and the work master is used to A process capability assigning means for performing processing for assigning the load of the added work process from the process performance date to the forward direction of the production process;
A production scheduling apparatus comprising: The production scheduling device according to claim 1 ,
A production scheduling apparatus, comprising: a display unit, wherein a screen showing a Gantt chart and a screen showing a work process load are displayed for each state of the intermediate parts.

Images