JPH0430043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a production control system for a production line that produces a wide variety of products.

A group of equipment in which workpieces such as semiconductor wafers are processed multiple times from the start of processing to completion;
In a production line that consists of equipment that undergoes processing only once, and the processing order differs depending on the type of product, the workpieces of the newly started lot are placed in front of the equipment that is used repeatedly. At the same time, the workpiece of the lot, which has already undergone considerable processing, exists as a work in progress.

When a lot passes through each piece of equipment only once, as in a normal flow-hop type line, or when the passing process does not change depending on the product type, the order in which the next lot to be worked on is selected from among the waiting lots is determined. Whether it is random or follows a certain rule, there is no significant difference in the overall in-process distribution state, in-process time, or waiting time for each lot. However, when a production line includes a group of equipment that is used repeatedly as described above, the in-process status of the entire line and the waiting time of each wafer are determined by the selection order of the processing items, such as semiconductor wafers. be greatly affected. Additionally, there are many factors involved in determining the optimal order, making selection of wafers to be worked on complicated.

Taking the case of the wafer manufacturing process as an example, due to the nature of the manufacturing process, it is possible to shorten the manufacturing period and
Uniformization is the most effective means for improving quality and increasing yield, and it is considered that there is an urgent need to equalize the amount of work in progress and shorten waiting time.

However, conventional wafer manufacturing lines are simply equipment installed in a factory, and do not have a neural system function that is responsible for collecting and providing information between each piece of equipment.

Therefore, there is no information to make a decision when selecting one of the wafers waiting in front of each piece of equipment, and the operator has no choice but to rely on the operator. Therefore, the selection of the next wafer to be processed is left to the discretion of the worker without proper selection criteria, which results in an increase in wafer processing waiting time and uneven distribution of work in progress. This led to quality deterioration and yield reduction.

This is the same on general manufacturing lines, and although shortening and equalizing manufacturing lead times and reducing work-in-process lead to lower production costs, for the reasons mentioned above, it is not possible to carry out work in the optimal order. Since this is possible, no measures have been taken in the past.

An object of the present invention is to provide a manufacturing line that solves the above-mentioned problems, shortens and equalizes the manufacturing period, and equalizes the load on each piece of equipment.

In order to achieve the above object, the production control system according to the present invention includes a target equipment, a dividing process, a detector, a control device, a storage shelf, and a display device, and the workpiece is Among the equipment groups used to process the workpiece until completion, some of the equipment groups are used to equalize the load on each equipment on the production line, which is used multiple times as the workpiece progresses. This is a production control method that aims to shorten and equalize manufacturing lead times, and the equipment of interest is one that specifies the most frequently used equipment group among the equipment groups where the workpiece is processed multiple times. The division process specifies the process from when the workpiece is processed in the equipment of interest until it is returned to the equipment of interest, and the entire process is divided using the equipment of interest as a delimiter, and the detector is It detects the passage of workpieces to each equipment and outputs information such as arrival of workpieces to equipment, start of processing, and completion to the control device.The control device receives information from the detectors. In information processing, first, the progress of the workpiece in the dividing process is predicted in detail according to predetermined rules, and then the progress of each workpiece after the dividing process is predicted. A rough prediction is made using other predetermined rules, and then the workpieces stored in the storage shelf are ordered based on the above two prediction results and predetermined criteria, and production instruction information is output to the display device. The storage shelf is placed near the equipment group of interest, and is used to store and wait the workpieces before the start of processing in the dividing process and the workpieces after processing. It is installed on a storage shelf, receives production instruction information from a control device, and displays the next workpiece to be processed by the corresponding equipment.

Embodiments in which the present invention is introduced into a wafer manufacturing process will be described below with reference to the drawings.

A series of wafer manufacturing processes involves a group of equipment where the workpiece is processed multiple times, such as a wafer cleaning device, a photoresist coating device, an exposure device, an oxide film etching device, etc., and a group of equipment where the workpiece is processed only once. It consists of a group of equipment, such as diffusion furnaces, oxidation furnaces, vapor deposition equipment, CVD equipment, etc. Therefore, among the equipment groups in which the workpiece is processed multiple times, the most frequently used equipment group, for example, the wafer cleaning equipment, is hereinafter referred to as the equipment of interest, and after the workpiece has been processed in the equipment of interest, it is returned to the equipment of interest again. The process until it returns is called the division process.

FIG. 1 is a block diagram showing an embodiment of the present invention. In Figure 1, Sa, Sb, Sc, and Sd correspond to equipment groups that are repeatedly used in the semiconductor wafer manufacturing process, such as wafer cleaning equipment, photoresist coating equipment, exposure equipment, oxide film etching equipment, etc. Among the sensors that are used repeatedly in the wafer manufacturing process, Sa indicates the equipment of interest that is particularly important for production control, and in the example, the sensor installed in the wafer cleaning equipment.

S1,1,S1,z...S1,3...,Sy,
n is a group of equipment used only once in the wafer manufacturing process, such as each diffusion furnace, oxidation furnace, vapor deposition device,
This shows a sensor attached to a CVD device, etc.

Si is a sensor that detects the start of wafer processing, and Se is a sensor that detects the completion of all process processing.

Each sensor has the function of detecting the wafer lot identification number each time a wafer arrives at each facility, the start and completion of processing, and the function of detecting a condition in which the product cannot be processed, such as an inspection failure of each facility. . In this embodiment, it is an online terminal.

Before processing at the above-mentioned facility group, CNB
It is a storage shelf that stores wafers, and CND is a display device attached to the storage shelf CNB.
Displays production instruction information from control device CN.

Here, the production instruction information is the wafer lot identification number (hereinafter referred to as lot number) that the corresponding equipment should process next.

The CN is a control device that outputs production instruction information to the display device CNB, and stores therein the scheduled passage time of each facility and all facility load capacity information for all processes of all lots within the system. It has the function of determining the next lot to be processed from among the lots waiting in the storage shelf in front of the equipment of interest.

The control device CN determines which lots should be processed in the following order. That is, first, the delay time from the scheduled time is calculated for each lot. Next, prediction within the division process is performed in descending order of delay time priority. On this occasion,
If it is predicted that the load capacity of each facility will be exceeded, it is removed from the target of instruction and predictions are made for the next priority lot.

As a result, those predicted to be less than the total process load capacity within the divided process are sent to the display device CNB as production instruction information. The flow of wafer lots and the flow of information according to this production control system will be explained based on FIG.

First, when a wafer lot is input, the lot number and the corresponding product name are notified to the control device CN. The control device CN internally creates all the manufacturing processes and scheduled passing times for the corresponding lot, and waits for subsequent reports from the sensors.

The loaded lot is placed on the storage shelf in front of the equipment of interest.
It will be stored in CNB first. When the control device CN makes a prediction for the corresponding lot, S1, 1, S2, 1, S3, 1, ..., Sb,
When the predicted in-process status of the equipment group corresponding to 1, . . . , Sc, 1 . And sensor S1,1,
Processed using dedicated equipment for each division process that responds to S2, 1, S3, 1, etc. and common equipment for each division process that corresponds to sensors Sb, Sc, Sd, etc., and stored again.
Return to CNB and have priority instructions again.

This loop is repeated several times, and the progress of the lot is always checked in front of the equipment of interest, and the order is readjusted to be optimal from the overall perspective.

According to the present invention, by performing work on the target equipment in the above-described steps, the processing order of delayed workpieces and workpieces that have been processed early can be adjusted, and each division step can be adjusted. The level of congestion will be equalized.

Therefore, the wafer processing period is made uniform, the amount of work in progress is equalized, and each piece of equipment can be used effectively, which is a great effect. Furthermore, it has the effect of significantly reducing the man-hours required for workers and process managers.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. Sa, Sb, Sc, and Sd indicate sensors associated with equipment groups used in the semiconductor wafer manufacturing process, such as wafer cleaning equipment, photoresist coating equipment, exposure equipment, oxide film etching, etc. . S1,1,S1,2...S1,3
..., Sy,n are equipment groups used only once in the wafer manufacturing process, such as each diffusion furnace, oxidation furnace,
It shows a sensor attached to a vapor deposition device, CVD device, etc. S1 is a sensor that detects the start of wafer processing, and Se is a sensor that detects the completion of all process processing. CN is a control device, CNB is a storage shelf where wafers are stored before being processed in the target equipment group, and CND is
This is a display device attached to storage shelf CNB.

Claims (1)

[Scope of Claims] 1. A system that includes a focused facility, a dividing process, a detector, a control device, a storage shelf, and a display device, and is capable of monitoring the workpiece from the start of machining to the completion of machining. Among the equipment groups used for processing, some equipment groups are used multiple times as the workpiece progresses, and the load on each equipment on the manufacturing line is equalized to shorten and equalize the manufacturing period. In this production control method, the equipment of interest is a group of equipment that is used most frequently among the equipment groups where the workpiece is processed multiple times, and the dividing process is the equipment of interest that processes the workpiece multiple times. This specifies the process from when the object is processed until it returns to the equipment of interest.The entire process is divided by the equipment of interest, and the detector detects the passage of the workpiece to each equipment. The controller detects the arrival of the workpiece to the equipment, the start and completion of processing, and outputs information to the control device.The control device processes the information from the detector and is responsible for information processing. First, the progress of the workpiece within the dividing process is predicted in detail using predetermined rules, and then the progress of each workpiece beyond the dividing process is roughly predicted using other predetermined rules. The system predicts, and then orders the workpieces stored in the storage shelf based on the above two prediction results and predetermined criteria, and outputs production instruction information to the display device. It is placed near the equipment group of interest, and stores and waits the workpieces before the start of processing in the dividing process and the workpieces after processing.A display device is installed on each storage shelf, and a display device is installed on each storage shelf, and is A production control system characterized by displaying a workpiece to be processed next by the corresponding equipment upon receiving production instruction information.