JP2702469B2 - Semiconductor wafer production method - 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 producing a semiconductor wafer, and more particularly to a method for controlling a production of a semiconductor wafer production line which requires many processing steps.

[0002]

2. Description of the Related Art A semiconductor wafer production line has a very large number of processing steps of 300 to 500 steps, and the manufacturing equipment for each step is very expensive. By using a job shop method, the same equipment is repeatedly used in different processes, and a semiconductor wafer (in the case of a lot composed of a plurality of semiconductor wafers, is simply referred to as a semiconductor wafer in this specification). We adopt a method of proceeding.

[0003] Accordingly, a plurality of semiconductor wafers are placed in each manufacturing apparatus of the semiconductor wafer production line regardless of the order of loading the semiconductor wafers. Further, the delivery date of the finished semiconductor wafer varies depending on the product type, and the semiconductor wafer immediately after the loading and the semiconductor wafer immediately before the storage may be placed on the same work equipment shelf.

Here, a method of determining a semiconductor wafer to be processed with the highest priority from a plurality of semiconductor wafers in process will be described with reference to FIG. Conventionally, in order for a worker to process the next semiconductor wafer with a certain manufacturing apparatus, the operator must confirm that the manufacturing apparatus is currently in a state capable of processing the semiconductor wafer (step 1), or the manufacturing apparatus processes the wafer. If it is in the middle, the worker judges the processing end time from experience and intuition (step 2), moves the worker to the work in progress shelf (step 3), and processes which semiconductor wafer in the work in progress shelf next. Is made to the production control device (step 4), and the production control device calculates the semiconductor wafer to be processed with the highest priority based on the previously prepared and input production plan and the results of work performed based on this production plan. And answered the worker (step 5). Then, the operator searches for a semiconductor wafer to be processed in accordance with an instruction from the production control device from a work in progress rack for the manufacturing device (step 6), and performs processing with the manufacturing device (step 7).

[0005]

As described above, in the conventional semiconductor wafer production method, the timing for determining the next semiconductor wafer to be processed is because the worker inquires the production control device. However, the timing is not constant depending on the operator, which causes the following problem.

(A) When the timing of deciding the next semiconductor wafer to be processed is early, the semiconductor wafer specified by the production control device is temporarily stored in a work-in-progress shelf and can be processed by the manufacturing device. Then, the semiconductor wafer is processed. This means that while a semiconductor wafer that is determined to be processed next is temporarily stored, a semiconductor wafer that must be processed in preference to this semiconductor wafer is placed on this work in progress shelf, Since the wafer has already been determined to be a temporarily stored semiconductor wafer, it cannot be mounted in a manufacturing apparatus before this and processed. Therefore, the closer the semiconductor wafer that must be processed preferentially to the process closer to the warehousing process, the more difficult it is to adhere to the delivery date of the semiconductor wafer.

(B) If the timing of deciding the next semiconductor wafer to be processed is late, the idle time of the manufacturing apparatus increases, so that the operating rate of the manufacturing apparatus decreases, the number of semiconductor wafers to be processed decreases, and the target production volume increases. Cannot be satisfied.

In addition, the following problem occurs because the operator searches for the location of the semiconductor wafer based on the processed semiconductor wafer number from the production control device.

(C) As the number of semiconductor wafers mounted on the work-in-progress work shelf increases, it takes time to search for a location, and a vacant time of the manufacture equipment is created, resulting in a reduction in the operation rate.

(D) As the number of semiconductor wafers mounted on the in-process rack for the manufacturing apparatus increases, a semiconductor wafer different from the processing semiconductor wafer number designated by the production control unit is searched and processed, and for this purpose, the production control unit issues an instruction. There is a possibility that it will be difficult to meet the deadline for delivery of the semiconductor wafer.

Accordingly, it is an object of the present invention to keep the timing for determining the next semiconductor wafer to be processed in a manufacturing apparatus constant, and not to directly rely on the operator to search for the determined semiconductor wafer from a work-in-progress shelf. By
It is an object of the present invention to provide an effective semiconductor wafer production method capable of reducing disturbance in a production plan and performing production according to a production plan drafted before semiconductor wafer introduction.

[0012]

SUMMARY OF THE INVENTION The present invention is characterized by a progress comparison / calculation unit for calculating and referring to a previously created production plan and actual production, and a production monitor for monitoring the state of a production apparatus. A device state monitoring unit, an inventory management unit that manages semiconductor wafers in process on the work in progress for processing by the manufacturing apparatus, and a work in progress control unit that automatically searches for semiconductor wafers to be processed by the manufacturing apparatus from the work in progress shelf To start the calculation of the production progress in the progress comparison and calculation unit by the timing signal from the manufacturing equipment state monitoring unit, determine the next semiconductor wafer to be processed, There is provided a semiconductor wafer production method for automatically retrieving wafers from the in-process shelf by the in-process shelf control unit. Here, the automatic search may include an automatic retrieval of the semiconductor wafer from the in-process shelf. Further, the timing can be performed when the loader of the manufacturing apparatus becomes empty.

[0013]

According to the above-described semiconductor wafer production method, the semiconductor wafer to be processed next by the manufacturing apparatus is calculated by the progress state comparison and calculation section based on the timing from the manufacturing apparatus state monitoring section. It is possible to process semiconductor wafers with priority and to keep the operation rate of the manufacturing apparatus constant. Further, since semiconductor wafers to be processed with the highest priority are automatically searched from the work-in-progress shelf, there is no need for operator search errors and the like, and semiconductor wafers can be produced as planned.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG.
FIG. 4 is a flowchart illustrating a production process targeted by the semiconductor wafer production method of the present invention, and FIG. 4 is a diagram illustrating steps in a part of the process in FIG.

As shown in FIG. 3, immediately after the semiconductor wafer is loaded, a P-well formation process and a field region formation process are performed, and further, formation processes of various places are performed, and an aluminum wiring formation process is performed to store the semiconductor wafer. I do.

As shown in the left column of FIG. 4, the P-well formation includes wafer cleaning, CVD insulating film growth, resist coating, exposure, development, etching, resist removal, impurity ion implantation, and activation heat treatment. The steps are sequentially performed on each manufacturing apparatus. On the other hand, as shown in the right column of FIG. 4, in order to form an aluminum wiring, each process of wafer cleaning, aluminum sputtering, resist coating, exposure, development, etching, and resist removal is sequentially performed by each manufacturing apparatus. As is clear from the figure, the formation of the P-well immediately after the loading and the formation of the aluminum wiring immediately before the storage are performed by wafer cleaning, resist coating, exposure,
The same manufacturing apparatus is commonly used in each of the development, etching, and resist removal steps.

Therefore, the semiconductor wafer for forming the P-well immediately after the loading and the semiconductor wafer for forming the aluminum wiring immediately before the loading are put on the work-in-process shelf for processing by the same manufacturing equipment.

FIG. 1 is an overall block diagram of a system for performing a method for producing a semiconductor wafer according to one embodiment of the present invention.
The system includes a progress comparison / calculation unit 3 that compares a production plan 1 created in advance with a production result 2 produced based on the production plan 1 to calculate a production progress, and
The processing is performed by a manufacturing apparatus state monitoring unit 4 that provides a timing signal for starting the calculation of the production progress state, an inventory management unit 5 that manages semiconductor wafers mounted on a work-in-progress shelf for this manufacturing apparatus, and a progress state comparison calculation unit 3. The in-process shelf controller 6 automatically retrieves the determined semiconductor wafers from the in-process shelves, retrieves them from the shelf, and issues a transport instruction. All of these components are controlled by a computer.

Next, the operation when a semiconductor wafer to be processed by this manufacturing apparatus is being mounted on a work in progress rack of the manufacturing apparatus will be described.

First, at the time when a wafer can be processed in the manufacturing equipment monitored by the manufacturing equipment state monitoring unit 4 in FIG. 1, the semiconductor wafer currently being processed is moved from the loader of the manufacturing equipment to the processing chamber. When the loader is empty and a wafer can be mounted when the loader becomes available, the manufacturing apparatus state monitoring unit 4 determines that the manufacturing apparatus can be processed or mounted on the loader of the manufacturing apparatus. And the timing of calculation start is given to the progress comparison / calculation unit 3 which is a production control device.

Next, the progress comparison / calculation section 3 extracts data of the semiconductor wafers mounted on the work-in-progress shelves from the inventory management section 5 to be processed by this manufacturing apparatus, and determines whether the data can be processed under the current conditions of the manufacturing apparatus. Judge whether. Note that the inventory management unit 5 has data on semiconductor wafers placed on a work-in-progress shelf for processing by the manufacturing apparatus. For example, if the processing condition of the semiconductor wafer being processed is 1000
In the case of oxidation at ° C., it is determined whether or not the manufacturing equipment of the oxidation furnace is at 1000 ° C. at present.

When the current state of the manufacturing apparatus can be processed, the degree of delay progress with respect to the manufacturing plan 1 is calculated from the manufacturing plan 1 created in advance and the production results 2 worked based on the manufacturing plan 1. The specific calculation method will be described later with reference to FIG.
This will be described with reference to FIG.

On the basis of the result of the calculation of the progress of the delay, the progress comparison / calculation section 3 determines a semiconductor wafer to be processed with the highest priority from among the semiconductor wafers in progress on the work-in-progress shelves. In response to this, the progress comparison / calculation unit 3 issues a delivery instruction and gives a worker or a transport robot a transport destination instruction. After issuing the instruction, the manufacturing apparatus state monitoring unit 4 confirms that the manufacturing apparatus is in a processable state. The in-process shelf controller 6 automatically searches for the specified semiconductor wafer from the in-process shelf. The automatically searched semiconductor wafers are automatically unloaded from the in-process shelf by a robot under the control of the in-process shelf control unit 6. The semiconductor wafer that has been automatically unloaded is transferred to a predetermined manufacturing apparatus by another transfer robot. Or semiconductor wafers that were automatically unloaded
The worker transports to a predetermined manufacturing apparatus according to a transportation instruction on a display panel or the like indicating which manufacturing apparatus to transport by the progress comparison / calculation unit 3.

Here, the automatic search will be described. When a semiconductor wafer is mounted on the in-process shelf, the work-in-shelf control unit 6 determines whether or not the semiconductor wafer is contained in the box containing the semiconductor wafer.
The position and ID of the semiconductor wafer are stored as D (barcode or the like). Then, the semiconductor wafer is searched based on the position and the ID of the semiconductor wafer specified by the progress comparison / calculation unit 3.

Next, if there is a wafer in the work-in-process shelf in front of the manufacturing apparatus, but there is no wafer that matches the manufacturing processing conditions of the manufacturing apparatus, for example, there is a work-in-progress semiconductor wafer in the work-in-process shelf for the manufacturing apparatus. The case where the processing conditions are oxidation at 1000 ° C. and the manufacturing apparatus is in an oxidizing atmosphere at 900 ° C. will be described. The manufacturing apparatus state monitoring unit 4
When it is recognized that the processing apparatus is in a processable state, that is, in the above example, it has been switched to the processable condition of 1000 ° C. and maintained at 1000 ° C., this is compared with the progress state comparison calculation unit 3
Notify. The progress status comparison / calculation unit 3 extracts the in-process information from the inventory management unit 5 and calculates and determines the semiconductor wafer to be processed with the highest priority among the semiconductor wafers to be oxidized at 1000 ° C. This determination method is the same as described above.

When a semiconductor wafer requiring an oxidation treatment at 900 ° C. is set on the work equipment shelf, the processing of the semiconductor wafer is generally performed before changing the conditions of the manufacturing equipment. Do. This is because it takes time to switch the conditions of the manufacturing apparatus.

Next, even when a semiconductor wafer is not ready on a work-in-progress shelf in front of the manufacturing apparatus, the manufacturing apparatus state monitoring section 4 keeps the processing state of the manufacturing apparatus. Then, when the in-process shelf control unit 6 recognizes that a semiconductor wafer that can be processed by the manufacturing apparatus has been mounted on the in-process shelf, it notifies the progress status comparison and calculation unit 3. The progress status comparison / calculation unit 3 extracts in-process information of a newly-processed semiconductor wafer from the inventory management unit 5, and if the processing conditions match the current processing state of the manufacturing apparatus, the semiconductor wafer is processed by the in-process shelf management unit 6. Is instructed to leave.

Next, an example of calculating the progress will be described with reference to FIG.

Here, the semiconductor wafer A and the semiconductor wafer B are mounted on the control device work shelf because they are processed by the same manufacturing apparatus under the same conditions, and when the manufacturing apparatus becomes ready for processing. In addition, both the semiconductor wafer A and the semiconductor wafer B can be processed.

The progress comparison / calculation unit 3 extracts a production plan and production results created in advance for all target wafers in order to calculate the progress of the in-process wafer.

[0031] In the semiconductor wafer A, the difference between the work possible time and production scheduled time due to manufacturing plan (shown by □) (indicated by ○), that is, the delay time is X _A, until the scheduled delivery time from production scheduled time due to the manufacturing plan time is Y _a.

[0032] In the semiconductor wafer B, the difference between the work possible time and production scheduled time due to manufacturing plan (shown by □) (indicated by ○), that is, the delay time is X _B, until the scheduled delivery time from production scheduled time due to the manufacturing plan Is Y _B.

In this case, which of the semiconductor wafers is to be preferentially processed is determined by dividing the delay time by the remaining time until the delivery date. The larger the solution (A = X / Y), the more strictly the delivery date is required. Is difficult.

In the semiconductor wafer A, A _A = X _A / Y _A , and the current state, that is, the operable time (○) is located on the danger line 1.

In the semiconductor wafer B, A _B = X _B / Y _B , which is larger than A _{A of the} semiconductor wafer A,
For this reason, the current state of the semiconductor wafer B, that is, the operable time (て い る) is located on the danger line 2 rising sharply from the danger line 1. This indicates that the semiconductor wafer B needs to be processed prior to the semiconductor wafer A.

Accordingly, in this case, the delivery date can be strictly controlled by controlling the semiconductor wafer B to be processed preferentially.

In the above-described processing, the production schedule 1 notifies the comparison calculation unit 3 of the estimated production time, the estimated delivery date, the estimated processing time, and the estimated transportation time. From the production record 2, the in-process process, that is, the start / end time, the transport time, and the like are notified to the comparison calculation unit 3. The operable time in this case is the sum of the calculation start time (the time at which the state monitoring unit 4 issues a semiconductor wafer payout request to the comparison calculation unit 3), the scheduled transfer time, and the scheduled setup time.

[0038]

As described above, the following effects can be obtained by the present invention.

The semiconductor wafer to be processed next is determined by the progress status comparison / calculation unit based on a signal from the manufacturing device state monitoring unit when the processable state or the mountable state of the manufacturing apparatus is triggered. Since the wafer is automatically searched without being searched, the production can be performed according to the manufacturing plan, and the delivery date can be strictly observed.

Further, since the semiconductor wafer to be processed next is determined according to a request from the manufacturing apparatus and the semiconductor wafer is processed, the operating rate of the manufacturing apparatus can be kept constant.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an entire semiconductor wafer production system according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a semiconductor wafer processing determination method according to an embodiment of the present invention.

FIG. 3 is a diagram exemplifying a manufacturing flow targeted by the semiconductor wafer production method of the present invention.

FIG. 4 is a block diagram illustrating steps in a part of the process in FIG. 3;

FIG. 5 is a block diagram showing a conventional semiconductor wafer production method.

Claims (4)

(57) [Claims] 1. A progress status comparison / calculation unit for calculating a production progress status by comparing a production plan and a production result created in advance, a production status monitoring unit for monitoring a processing status of a production device, An inventory management unit that manages the semiconductor wafers in process on the in-process shelf for processing, and a system having a in-process shelf control unit that automatically searches the in-process shelf for semiconductor wafers to be processed by the manufacturing apparatus,
Calculation of the production progress in the progress comparison / calculation section is started by a timing signal from the manufacturing apparatus state monitoring section, a semiconductor wafer to be processed next is determined, and the semiconductor wafer is processed by the work in progress control section by the work in progress shelf. A method for producing a semiconductor wafer, wherein the method is automatically searched for from a semiconductor wafer. 2. The semiconductor wafer production method according to claim 1, wherein said automatic search includes an automatic unloading of said semiconductor wafer from said in-process shelf. 3. The computer according to claim 1, wherein all of said parts of said system are controlled by a computer.
A method for producing a semiconductor wafer as described in the above. 4. The method according to claim 1, wherein said timing is performed when a loader of said manufacturing apparatus is vacant.