JP2010056108A - Process monitoring method, mass measuring method, and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process monitoring method measuring a physical change of a semiconductor wafer observed before and after each semiconductor manufacturing process. <P>SOLUTION: In monitoring, a measuring cassette into which a mass meter for measuring the mass of a wafer to be processed is incorporated is prepared and attached to first load ports 2a to 2c. Wafer carrier containers 3a, 3c with semiconductor wafers housed therein are attached to adjacent second load ports 2a to 2c. The semiconductor wafer housed in the wafer carrier container is transferred into the measuring cassette, the mass of the wafer is measured and first measurement data is transmitted to a signal processing means 6 disposed outside of the cassette. At the completion of a process, the processed wafer is housed in the cassette. The mass of the wafer after processed is measured by the mass meter and measured second measurement data is transmitted to the signal processing means 6. A change in physical quantity of the wafer before and after processed is calculated using the first and second measurement data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a process monitoring method for monitoring a change in a physical quantity of a wafer due to process processing by measuring a change in the mass of the wafer before and after the process.

  The present invention also relates to a mass measuring method and apparatus suitable for semiconductor wafer process monitoring.

  A semiconductor integrated circuit is manufactured by performing various manufacturing processes such as polishing, film formation, etching, and impurity implantation on a semiconductor wafer. In these semiconductor manufacturing processes, it is extremely important to measure the physical quantity of a wafer and monitor the progress of the process in order to increase the device yield. For example, when a film forming apparatus or vapor phase growth apparatus is used as a semiconductor manufacturing apparatus, the film thickness of an aluminum wiring film or a barrier metal film such as titanium or tantalum is accurately measured in managing the process. Is required to do. Further, when the surface of the wafer is subjected to CMP (Chemical Mechanical Polishing) processing or back grinding processing, it is necessary to measure the polishing amount and to accurately manage the thickness of the wafer. Furthermore, it is necessary to monitor and manage the etching depth in the etching process.

  Conventionally, the film thickness of a film formed on a wafer has been optically measured. In high-precision optical measurement, it is possible to measure the film thickness of the film formed on the wafer with a resolution of 0.5 nm. However, when optically measuring the film thickness of the film formed on the wafer, the wafer must be taken out of the semiconductor production line, and the taken-out wafer must be carried into an optical measuring device for measurement. For this reason, it has been difficult to optically measure changes in the physical quantity of the wafer in various processes optically in-line during the manufacturing process of the semiconductor device.

  As an example of in-line measurement, an inspection method for inspecting a substrate transport unit by measuring the weight of the substrate transport unit using a weight sensor has been proposed (for example, see Patent Document 1). In this known inspection method, whether or not a protective cover or a reticle is accommodated in the transport container is detected by measuring the weight of the substrate transport unit.

  Further, a monitoring method for measuring the mass of a semiconductor wafer before and after the process and measuring the physical quantity of the semiconductor wafer based on the change in the mass of the wafer before and after the process is known (for example, see Patent Document 2). In this known monitoring method, a mass meter is arranged in the front chamber of a process chamber of a semiconductor manufacturing apparatus, a change in the mass of the semiconductor wafer before and after the etching process is measured, and the process is managed based on the measured mass. .

Further, as a mass meter, a mass meter capable of a minimum display of 0.1 mg has been put into practical use (for example, see Patent Document 3). If such a mass meter capable of precise measurement is used, it is expected to obtain information useful for process management in the semiconductor manufacturing process.
JP 2008-147281 A JP 2001-118762 A Shimadzu website

  In the semiconductor device manufacturing process, a semiconductor wafer is stored in a transfer container (FOUP: Front Opening Unified Pod), and the transfer container in which the wafer is stored is transferred between the semiconductor manufacturing apparatuses. Semiconductor manufacturing systems that perform in-line are widely used. In this semiconductor manufacturing system, a load port is disposed on the front surface of a semiconductor manufacturing apparatus that performs process processing on a wafer, the transport container that has been transferred is mounted on the load port, and the wafer is taken out of the transport container at the load port. It is carried into the semiconductor manufacturing equipment. In this semiconductor manufacturing system, for example, when optically measuring the film thickness of a film formed on the wafer surface, the processed wafer must be taken out of the semiconductor device manufacturing line and placed in the optical device. It was difficult to measure inline on the line. Further, in the mass measurement method described in Patent Document 2 described above, mass measurement is performed in the front chamber of the process chamber of the semiconductor manufacturing apparatus. Therefore, there is an advantage that the mass of the semiconductor wafer immediately before and after the process can be measured. . However, since the mass meter is always arranged, it is necessary to provide a dedicated space for arranging the mass meter inside the semiconductor manufacturing apparatus, which causes a problem in terms of spatial utilization of the semiconductor manufacturing apparatus.

  If a mass meter with a minimum display of 0.1 mg is used, the mass change of the semiconductor wafer can be measured with high accuracy, and useful information for process management is expected. In particular, if an existing production line can be used for in-line measurement, a change in the physical quantity of the semiconductor wafer can be measured in real time for each process, which is extremely effective for process management. However, when mass measurement is performed using the mass meter, there is a characteristic that an external factor causes an error. In particular, the semiconductor wafer is in the direction of increasing its diameter, and in the case of a 300 mm wafer, the thickness is about 0.775 mm, and since it has a thin flat plate structure, it is susceptible to the influence of airflow and convection in the measurement atmosphere . For this reason, even if a slight convection is generated in the atmosphere in the vicinity of the mass meter, a slight vibration is generated in the semiconductor wafer, resulting in variations in measured values and causing measurement errors. In particular, in a clean room where semiconductor manufacturing equipment is installed, downflow is always formed, so the effect of airflow is large, and measurement that is unsuitable for measuring the mass of a semiconductor wafer with a minimum display unit of 0.1 mg The environment.

  An object of the present invention is to realize a process monitoring method capable of measuring in-line changes in physical quantities of a semiconductor wafer before and after various semiconductor manufacturing processes.

  Another object of the present invention is to realize a mass measuring method and a mass measuring apparatus capable of measuring a physical quantity of a semiconductor wafer in-line using a mass meter having a minimum display performance of 0.1 mg.

A process monitoring method according to the present invention is a process monitoring method for monitoring a change in a physical quantity of a semiconductor wafer due to a semiconductor manufacturing process by measuring a change in the mass of the wafer before and after the semiconductor manufacturing process,
A mass meter for measuring the mass of a semiconductor wafer to be processed is incorporated, and a measurement cassette that can be attached to a load port of a semiconductor manufacturing apparatus is prepared, and the measurement cassette is exchangeably attached to a load port of a semiconductor manufacturing apparatus. Process,
Storing the semiconductor wafer to be monitored in the measurement cassette;
Prior to the process, the mass of the semiconductor wafer is measured in a state where the measurement cassette is mounted on the load port, and the measured first measurement data is sent to the signal processing means arranged outside the measurement cassette. Sending, and
After the predetermined process is completed, a process of storing the processed semiconductor wafer in the measurement cassette;
Measuring the mass of the processed semiconductor wafer by the mass meter, and transmitting the measured second measurement data to the signal processing means;
The signal processing means includes a step of calculating a change in the physical quantity of the semiconductor wafer before and after the processing using the first measurement data and the second measurement data.

  In an electromagnetic force balance type mass meter, the minimum display is 0.1 mg, and ultra-precise mass measurement is possible. When the present inventor converted the minimum display of 0.1 mg into the film thickness of the aluminum coating film formed on the semiconductor wafer having a diameter of 300 mm, it was found that it corresponds to the film thickness of 0.52 nm. This minimum display is almost comparable to the resolution of the film thickness obtained when measured optically. Further, when a TiN film used as a barrier metal is formed on a semiconductor wafer having a diameter of 300 mm, a minimum display of 0.1 mg corresponds to a film thickness of 0.26 nm. Further, in the case of a silicon oxide film, a minimum display of 0.1 mg corresponds to a film thickness of 1.2 nm. According to these analysis results, it is possible to manage the semiconductor manufacturing process with high accuracy by measuring the mass of the semiconductor wafer. Moreover, if the mass of the semiconductor wafer before and after the process is measured, the physical quantities such as various coating films formed on the semiconductor wafer, the etching amount, and the polishing amount can be directly obtained simply by performing conversion processing on the measurement data in the signal processing means. Can be measured automatically. Therefore, in the present invention, various semiconductor manufacturing processes are monitored using a mass meter capable of measuring ultra-precision.

  However, as described above, the semiconductor wafer has a thin flat plate structure and a large area of the main surface with respect to the mass. Therefore, the semiconductor wafer has inherent characteristics that are easily affected by convection and static electricity in the measurement atmosphere. When measuring mass with resolution, there is a problem that measurement errors are likely to occur due to external factors such as convection. In order to solve this problem, in the present invention, a measurement cassette that can be mounted on a load port of a semiconductor manufacturing apparatus is prepared, and a mass meter is incorporated in the cassette to constitute a mass measurement apparatus. If a mass meter is incorporated in a measurement cassette, a substantially sealed space is formed, and a mass meter and a semiconductor wafer are arranged in the sealed space, thereby suppressing the influence of convection due to external temperature distribution. The problem that the measurement error is likely to occur is solved.

  In a current semiconductor manufacturing system, a system in which a wafer to be processed is accommodated in a transfer container (FOUP) and the transfer container is transferred between semiconductor manufacturing apparatuses is widely adopted. In addition, a load port for taking in and out a wafer to be processed is standardly provided in a semiconductor manufacturing apparatus, and a transfer container is standardized together with the load port. Therefore, if a FOUP container body is used as a measurement cassette and a mass meter for measuring the mass of a wafer to be processed is incorporated in a transfer container, it is possible to perform in-line measurement at a load port of a semiconductor manufacturing apparatus. . What is important here is that, according to the present invention, in the load port that is standardly provided in a semiconductor manufacturing apparatus, the wafer mass can be obtained simply by mounting a measurement cassette with a built-in mass meter on the load port. Can be measured. If the mass can be measured at the load port, the mass of the wafer immediately before the process process is executed can be measured, and the mass of the processed wafer can be measured immediately after the process is completed. That is, a major error factor in measuring the wafer mass in units of 0.1 mg is that the measurement conditions vary with time. However, in the present invention, the two measurements performed before and after the process processing are performed on the same load port in the same mass measuring apparatus, and can be measured immediately before the processing and immediately after the processing. The error due to the variation in conditions is reduced, and the advantage that highly reliable measurement data can be obtained is achieved.

  Therefore, according to the present invention, it is possible to measure a change in the mass of a semiconductor wafer in-line without changing the production line in a measurement environment in which the influence of external factors such as convection is reduced. It is possible to manage various physical quantities such as the film thickness and etching amount of the film formed in a highly accurate manner.

  Here, the term “semiconductor wafer” or “wafer” includes an unprocessed bare wafer and a semiconductor wafer and a semiconductor substrate that have been subjected to various processes such as a film forming process and an etching process during the manufacturing process of the semiconductor device. Moreover, it can apply to the mass measurement of a silicon | silicone and a compound semiconductor as a semiconductor material. Further, the physical quantity of the wafer includes the mass of the wafer, the film thickness and etching amount of various coatings formed on the wafer, the polishing amount for the wafer, and the like.

  In a preferred embodiment of the process monitoring method according to the present invention, in a state in which the wafer transfer container is mounted on the load port of the semiconductor manufacturing apparatus, the wafer is mounted on and removed from the mass meter using a handler provided in the semiconductor manufacturing apparatus. Is performed.

  The load port is equipped with an opener that opens and closes the lid of the transfer container and a handler for transferring a wafer disposed in the transfer container. The handler can be operated two-dimensionally in a horizontal plane and can also be operated in the vertical direction. Therefore, by using the handler, the wafer held in the transfer container can be mounted on the wafer stage of the mass meter, and the wafer after measurement can be removed from the stage and transferred to the load lock chamber. Is possible. Therefore, by using the handler provided in the semiconductor manufacturing apparatus, it is possible to automatically execute operations from the transfer to the semiconductor manufacturing apparatus to the mass measurement after the process processing.

The process monitoring method according to the present invention is a process monitoring method for monitoring a change in a physical quantity of a semiconductor wafer due to a semiconductor manufacturing process by measuring a change in mass of the semiconductor wafer before and after the semiconductor manufacturing process at a load port provided in the semiconductor manufacturing apparatus. There,
A mass meter that measures the mass of the semiconductor wafer to be processed is built in, and a measurement cassette that can be attached to the load port of the semiconductor manufacturing apparatus is prepared. The measurement cassette can be replaced with the first load port of the semiconductor manufacturing apparatus. A process of attaching to,
Arranging a wafer transfer container in which one or a plurality of semiconductor wafers to be processed are accommodated and transferred along a semiconductor manufacturing line in a second load port adjacent to the first load port of the semiconductor manufacturing apparatus. When,
Using a handler provided in the semiconductor manufacturing apparatus, transferring the semiconductor wafer accommodated in the wafer transfer container into the measurement cassette;
A step of measuring the mass of the semiconductor wafer using a mass meter incorporated in the measurement cassette, and transmitting the measured first measurement data to a signal processing means arranged outside the measurement cassette;
Using the handler, removing the mass-measured semiconductor wafer from the mass meter and transferring it to the processing chamber of the semiconductor manufacturing apparatus;
After the predetermined process is completed, a process of storing the processed semiconductor wafer in the measurement cassette;
Measuring the mass of the processed semiconductor wafer by the mass meter, and transmitting the measured second measurement data to the signal processing means;
The signal processing means includes a step of calculating a change in the physical quantity of the semiconductor wafer before and after the processing using the first measurement data and the second measurement data.

  As described above, in a current semiconductor manufacturing system, a system in which a wafer to be processed is accommodated in a transfer container (FOUP) and the transfer container is transferred between semiconductor manufacturing apparatuses is widely adopted. In addition, a load port for taking in and out a wafer to be processed is standardly provided in a semiconductor manufacturing apparatus, and a transfer container is standardized together with the load port. Accordingly, among the plurality of load ports, a measurement cassette in which a mass meter is incorporated in the first load port is replaceably mounted, and a wafer transfer container to be transferred is disposed in the adjacent second load port. For example, by operating the handler, the semiconductor wafers accommodated in the wafer transfer container can be sequentially supplied into the mass meter. As a result, the semiconductor wafers sequentially transferred can be automatically and sequentially subjected to mass measurement and process processing under the control of the controller. Furthermore, since the measurement cassette incorporating the mass meter is replaceably attached to the load port, the advantage that the cassette can be replaced according to the characteristics of the semiconductor wafer to be processed is achieved. Accordingly, the calibration dummy wafer can be appropriately replaced.

  Here, it is particularly important that according to the present invention, it is possible to perform in-line mass measurement using an existing semiconductor manufacturing apparatus without providing a new mass measurement station in the middle of the production line. It is. In other words, mass measurement and process processing are performed on semiconductor wafers transferred along the production line simply by installing a FOUP with a built-in mass meter in a load port that is standard equipment on existing semiconductor manufacturing equipment. Can be performed sequentially. In other words, a FOUP incorporating a mass meter can be attached to an existing load port, and a semiconductor wafer accommodated in the FOUP transferred along the production line is handled by a handler (robot) provided in the semiconductor production apparatus. ) Can be transferred into a FOUP with a built-in mass meter. Therefore, a wafer transfer container that is transferred along a production line by using a handler equipped in an existing semiconductor manufacturing apparatus by simply mounting a measurement cassette containing a mass meter on a load port. The semiconductor wafer accommodated in the inside can be placed on the mass balance in the measurement cassette to perform mass measurement.

The mass measurement method according to the present invention is a mass measurement method for measuring the mass of a semiconductor wafer in-line between various process steps,
Mounting a measurement cassette in which a mass meter for measuring the mass of a semiconductor wafer is incorporated in a first load port of a semiconductor manufacturing apparatus in an exchangeable manner;
A wafer transfer container that contains one or a plurality of semiconductor wafers to be measured and is transferred along a semiconductor manufacturing line is arranged in a second load port adjacent to the first load port of the semiconductor manufacturing apparatus. Process,
Using a handler provided in the semiconductor manufacturing apparatus, transferring the semiconductor wafer accommodated in the wafer transfer container into the measurement cassette;
And measuring the mass of the semiconductor wafer using a mass meter incorporated in the measurement cassette and transmitting the measurement data to signal processing means arranged outside the cassette.

In the mass measurement method according to the present invention, since the mass measurement is performed by the mass meter disposed in the cassette attached to the load port of the semiconductor manufacturing apparatus, the semiconductor wafer is inlined in a measurement environment in which the influence of external factors is suppressed. It becomes possible to measure the mass. In particular, when a mass meter is incorporated in a measurement cassette, mounting and demounting of a semiconductor wafer to be measured in a cassette can be operated using an existing handler. It can be done automatically under the control of the controller.
A mass measuring apparatus according to the present invention is a mass measuring apparatus that measures the mass of a semiconductor wafer at a load port provided in a semiconductor manufacturing apparatus,
A container body that is replaceably attached to the load port and has an opening for taking in and out a semiconductor wafer to be measured;
A mass meter body that is disposed within the container body and measures the mass of the semiconductor wafer;
A wafer stage connected to the mass meter body and supporting the wafer to be measured so that its main surface is perpendicular to the vertical direction;
A dummy wafer having substantially the same shape as the semiconductor wafer to be measured and having a known mass in advance and a dummy wafer holding means for holding the dummy wafer;
A signal transmission means for transmitting a measurement value measured by the mass meter to a signal processing means arranged outside the container body,
A semiconductor wafer to be measured is arranged on the wafer stage by a handler of a semiconductor manufacturing apparatus when mounted on a load port.
Another mass measuring apparatus according to the present invention is a mass measuring apparatus suitable for measuring the mass of a semiconductor wafer having a minimum display unit of 0.1 mg,
A container body having an opening for taking in and out a semiconductor wafer;
A mass meter unit arranged in the container body and capable of measuring the mass of the semiconductor wafer in a minimum display unit of 0.1 mg;
A wafer stage connected to the mass meter unit and supporting the semiconductor wafer to be measured;
First and second covers arranged so as to be substantially parallel to the main surface of the semiconductor wafer, when the semiconductor wafer to be measured is placed on the wafer stage, spaced apart vertically so as to sandwich the wafer stage ,
A dummy wafer which is provided in the container body and has substantially the same shape as the semiconductor wafer to be measured and whose mass is known in advance and dummy wafer holding means for holding the dummy wafer;
A signal line for transmitting the measurement data measured by the mass meter unit to the outside of the container body,
The first and second covers include a thermally conductive conductive plate and a heat insulating member provided on the surface of the conductive plate.

  A problem in measuring the mass of a semiconductor wafer with a minimum display unit of 0.1 mg is that undesired stress acts on the semiconductor wafer due to convection, resulting in variations in measured values. On the other hand, since a semiconductor wafer has a large main surface and a thin flat plate structure, it has a characteristic that it is easily affected by convection. Therefore, in the present invention, the first and second covers that are separated in the vertical direction across the wafer stage are arranged, and these covers are arranged with respect to the main surface (element formation surface) of the semiconductor wafer arranged on the wafer stage. Arrange them so that they are almost parallel to suppress the effect of convection. The first and second covers include a heat conductive conductive plate and a heat insulating material provided on the conductive plate. By surrounding the periphery of the semiconductor wafer with a heat insulating material, it is configured not to be thermally influenced from the outside. Further, by surrounding with a plate of a good thermal conductor, it is possible to prevent a temperature gradient from being formed around the semiconductor wafer. Particularly, since the first and second covers are arranged in parallel to the main surface of the semiconductor wafer, a uniform measurement atmosphere is formed over the entire main surface of the semiconductor wafer. Therefore, by surrounding the wafer stage with a composite member of a heat insulating material and a good thermal conductor in the vertical direction in the container body, the influence of convection due to the temperature gradient is greatly reduced, and highly reliable mass measurement can be performed. it can.

  In a preferred embodiment of the mass measuring apparatus according to the present invention, the first and second covers are arranged such that the distance from the semiconductor wafer to the first cover and the second cover when the semiconductor wafer to be measured is arranged on the stage. The distance is set to be substantially equal to the distance up to. When the present inventor measured the mass of a semiconductor wafer using a mass meter having a minimum display unit of 0.1 mg, it was found that not only the influence of convection but also the influence of the charged charge charged on the surface of the semiconductor wafer cannot be ignored. . That is, when the surface of the semiconductor wafer comes into contact with various members, the electric charge is charged by frictional charging. On the other hand, if a conductive member is present around the surface of a semiconductor wafer having a charged electric charge, charges of opposite polarity are induced by electrostatic induction, and an undesirable Coulomb force is generated between the semiconductor wafer and the conductive member. Will occur. This Coulomb force cannot be ignored when measured in the minimum display unit of 0.1 mg, and causes an error. Therefore, in the present invention, the distance from the semiconductor wafer to be measured to the conductive first and second covers is set to be substantially the same. In this way, if the distance from the semiconductor wafer to the conductive cover is set to be equal, the charges induced in the first cover and the second cover are almost equal over almost the entire main surface, which is undesirable. Generation of high Coulomb force is prevented, and highly reliable measurement data can be obtained.

  In the present invention, a mass meter is incorporated inside, and mass measurement is performed using a measurement cassette that can be attached to a load port that is standardly equipped in a semiconductor manufacturing apparatus, so external factors such as convection are suppressed. In the measurement environment, the change in the physical quantity of the wafer immediately before and after the process can be measured in-line. As a result, it becomes possible to monitor a change in the physical quantity of the semiconductor wafer using a mass meter with an accuracy of 0.1 mg as the minimum display.

  FIG. 1 is a diagram showing the overall configuration of a semiconductor manufacturing system for implementing a process monitoring method according to the present invention. In this example, a description will be given by taking as an example a system in which semiconductor wafers to be subjected to various processes are accommodated in a transfer container (FOUP: Front Opening unified Pod) and transferred between semiconductor manufacturing apparatuses. In this semiconductor manufacturing system, FIMS (Front Opening Interface Mechanical System) that maintains a highly clean state in a transfer container for storing wafers and in a space for transferring wafers is adopted. In view of the characteristics of this FIMS system, in the present invention, a mass meter for measuring the mass of a wafer is incorporated in a transfer container or a semiconductor manufacturing apparatus that is maintained in a clean atmosphere, so that a change in the mass of the wafer is clean. Measure inline in an atmosphere or in a vacuum atmosphere. In this example, a mass meter is incorporated in the transfer container, and the change in the physical quantity of the wafer before and after the process is monitored by measuring the mass of the wafer in-line.

  In the semiconductor manufacturing apparatus 1, various processes are performed on the semiconductor wafer. As a process performed in the semiconductor manufacturing apparatus, a film forming process, a coating process, a polishing process such as back grinding and CMP, an etching process, and the like are performed. Examples of the film forming process include a process of forming various films such as an aluminum wiring film and a barrier metal layer on a wafer and a process of forming a film by a vapor deposition method such as CVD. An oxide film forming process is also performed in which a silicon oxide film is formed by performing a thermal oxidation process on a silicon wafer. The mass of the wafer before and after the film formation process is measured, and the measured value is transmitted to the signal processing means disposed outside the transfer container, and the mass of the wafer itself, the film thickness of the coating formed on the wafer, the polishing amount, etc. Changes in physical quantities of wafers are output in real time.

  Three load ports 2a to 2c are arranged adjacent to the semiconductor manufacturing apparatus 1, and wafer transfer containers 3a and 3c containing wafers are mounted on the load ports 2a and 2c. Each of the load ports 2a to 2c has an opening for loading and unloading the wafer, a door for closing the opening, and a mounting table 4a to 4c for supporting the transfer container. The mounting table is provided with positioning pins (not shown), and the transfer container is positioned by the positioning pins.

  Mass meters are incorporated in the transfer containers 3a and 3c, and the wafer mass before and after the process is measured in a state where the wafer is mounted in the transfer container. It is transmitted to the signal processing circuit 6 via 5a and 5c. The wafer in the transfer container is taken out by a handler (robot) provided in the semiconductor manufacturing apparatus, and is carried into the semiconductor manufacturing apparatus, and a predetermined process is performed. In the present invention, prior to execution of a process by a semiconductor manufacturing apparatus, wafer mass measurement is performed using a mass meter incorporated in a transfer container with the transfer container mounted on a load port. Thereafter, a predetermined process is performed in the semiconductor manufacturing apparatus, and the processed wafer is accommodated in a transfer container after the process is completed. And the mass of the wafer after a process is measured in the state which accommodated the wafer in the conveyance container.

FIG. 2 is a diagram showing an example of a semiconductor manufacturing apparatus. In the first transfer chamber 10, openers 11 a to 11 c facing the transfer container are arranged, and the openers 11 a to 11 c open and close the lid for taking in and out the wafer of the transfer container. A first handler 12 for transferring a wafer is disposed in the first transfer chamber 10, and a semiconductor wafer is operated using the first handler. The first handler 12 is controlled by a controller (not shown) and can move and rotate two-dimensionally and horizontally on a horizontal plane. The semiconductor wafer accommodated in the transfer container is placed on the mass scale by the first handler 12, is subjected to mass measurement, removed from the mass meter using the handler 12 after measurement, and transferred to the load lock chamber 13. .
The wafer transferred to the load lock chamber 13 is transferred into the first process chamber 16 by the second handler 15 disposed in the second transfer chamber 14 and processed. In this example, an aluminum film is formed by sputtering, for example, as a process treatment. When the process in the process chamber 16 is completed, it is taken out by the handler 15 and transferred to the cooling chamber 17 to perform a cooling process. When the cooling process is completed, the second handler 15 takes out the cooling chamber and transfers it to the unload lock chamber 18. The wafer transferred to the unload lock chamber is transferred to the transfer container 3a by the first handler 12. Then, the mass of the processed semiconductor wafer is measured in the transfer container 3a.

  FIG. 3 is a schematic cross-sectional view showing an example of a transport container (FOUP) according to the present invention. FIG. 3 (A) is a schematic plan view showing an arrangement mode of a mass meter and a semiconductor wafer. B) is a diagrammatic cross-sectional view seen from the side with the lid for taking in and out the wafer removed. The transport container has a container body 20 and a lid 21 for opening and closing. The container body 20 has an opening formed on the front surface of the container body 20 in order to take in and out the semiconductor wafer, and the opening is sealed with a lid 21. A mass meter unit 22 is disposed in the container body 20. The mass meter unit 22 can measure the mass of the wafer with an accuracy with a minimum resolution of 0.1 mg, for example. As the mass meter, for example, an analytical balance (trade name “AUD-D series”) manufactured by Shimadzu Corporation can be used. A wafer stage 24 that supports the wafer 23 to be measured is provided on the mass meter unit 22. The wafer stage 24 is made of a conductive material such as SiC or carbon. As illustrated, the wafer stage 24 supports the wafer 23 such that its main surface is orthogonal to the vertical direction. The wafer 23 is placed on the stage 24 using a handler, and the mass of the wafer 23 is measured in a state of being placed on the stage 24.

  The first and second covers 25 and 26 are attached so as to be spaced apart in the vertical direction across the stage 24. The first and second covers 25 and 26 are disposed so as to be substantially parallel to the main surface (element formation surface) of the semiconductor wafer when the semiconductor wafer 23 is disposed on the wafer stage 24. The first and second covers are constituted by plate members 25a and 26a having high thermal conductivity and conductivity and heat insulating sheets 25b and 26b, respectively. As a high thermal conductivity and good conductive material, for example, an aluminum plate is used. As a result of various experiments and analyzes by the present inventor, the greatest cause of mass meter error is the effect of convection near the wafer stage 24, and convection is generated by a temperature gradient formed around the stage 24. There was found. Therefore, in the present invention, a composite of a high thermal conductive plate and a heat insulating sheet is arranged in the vertical direction across the stage 24 supporting the wafer, and the semiconductor wafer 23 arranged on the wafer stage is measured in a sealed state. Maintain the atmosphere.

  By surrounding the periphery of the semiconductor wafer with a high thermal conductivity plate, the temperature gradient formed around the semiconductor wafer to be measured is greatly reduced, and the influence of convection is eliminated. Moreover, the influence by the temperature distribution outside the container is also eliminated by the heat insulating material. Thus, by arranging the cover made of the composite of the highly conductive plate and the heat insulating sheet, errors due to convection are greatly reduced.

  Further, according to the analysis result of the inventor, it has been found that the electrostatic charge generated on the wafer surface is also an error factor of the mass meter. That is, when an electrostatic charge is generated on the wafer surface, an undesired potential gradient is formed with the surrounding conductive member, and an undesired Coulomb force is generated. This Coulomb force causes a measurement error. Therefore, in the present invention, the first and second covers are made of a conductive material, and the distance from the wafer 24 placed on the stage 24 to the first cover and the distance to the second cover are as follows. Set to be approximately equal. The thickness of the wafer is about 0.775 mm, and when the electrostatic charge is charged on the wafer surface, the charge charged on the wafer surface is very small compared to the distance from the first and second covers to the wafer. It can be regarded as a charge charged in a planar shape. Accordingly, if the distances from the wafer placed on the stage to the first and second covers are set to be equal, the charges induced in the conductive plates constituting each cover are the main surface of the semiconductor wafer. Of the first cover and the second cover are almost equal to each other over almost the entire region of the surface, and generation of an undesirable Coulomb force is prevented. The first and second covers, the stage of conductive material, and the mass meter are preferably grounded and set to the same potential.

  A first signal line 27 for transmitting measurement data is connected to the mass measurement unit 22, and the other end of the first signal line is connected to the connector 28. The connector 28 extends to the outside of the transport container through a through hole formed in the side wall of the transport container. The other end of the connector 28 is connected to the second signal line 29, and the second signal line is connected to the signal processing circuit.

  Wafer holding shelves 30 a to 30 c that function as wafer holding means for holding wafers are provided on the upper portion of the container body 20, and hold the wafers 31 to be processed and the dummy wafers 32. Wafer holding shelf 30 holds each wafer such that its main surface extends in a direction perpendicular to the vertical direction. The interval between the wafer holding shelves is set so that the handler is inserted. Therefore, the wafer held on the wafer holding shelf 30 is taken out of the wafer holding shelf and placed on the wafer stage 24 by operating the first handler 12 (see FIG. 2) provided in the semiconductor manufacturing apparatus. be able to. In addition, the wafer and dummy wafer that have been placed on the wafer stage 24 and have been measured can be removed from the wafer stage by the first handler 12 and placed on the wafer holding shelf, or transferred to the load lock chamber. can do. Thus, in the transfer container according to the present invention, the wafer held on the wafer holding shelf can be mounted on the mass meter using the existing handler or robot provided in the semiconductor manufacturing apparatus, and the wafer whose measurement has been completed. Can be placed on the wafer holding shelf. This handler operation can be automatically executed by the controller. Therefore, by using the transfer container according to the present invention, it is possible to automatically output in real time changes in the physical quantity of the wafer before and after the process in the semiconductor manufacturing apparatus. For the sake of clarity, the three wafer holding shelves 30a to 30c are shown, but it is of course possible to provide a large number of wafer holding shelves.

  The dummy wafer 32 held in the transfer container will be described. In order to measure the mass of the wafer with a minimum unit of 0.1 mg, it is necessary to calibrate the mass meter at the time of measurement. In particular, if it takes a long time from measurement before the process to measurement after the process, if there are fluctuations in atmospheric pressure or temperature, the mass meter will fluctuate during that time, causing an error. Therefore, in this example, the dummy wafer 32 for measuring the calibration data is held on the wafer holding shelf of the transfer container and calibrated using the measured value. The dummy wafer 32 has a known mass, is configured with a wafer having substantially the same shape as the measurement target wafer and a mass comparable to that of the measurement target wafer. Therefore, the dummy wafer measurement operation can be performed by the same operation as the wafer. Note that, in order to measure the mass of the wafer with a minimum unit of 0.1 mg, it is necessary to match the center of gravity of the semiconductor wafer to be measured with the center of gravity of the calibration dummy wafer. Therefore, in the present invention, calibration is performed using a dummy wafer having substantially the same shape as the semiconductor wafer whose mass is measured. When the shapes of the measurement objects are the same, the barycentric positions coincide with each other, so that an error caused by calibration is prevented.

  Prior to measurement of the wafer to be processed, a dummy wafer is taken out of the wafer holding shelf and placed on the stage by a handler (first handler 12 shown in FIG. 2) provided in the semiconductor manufacturing apparatus, and the mass of the dummy wafer is measured. . And the measured value is transmitted to a signal processing means via a signal line. Thereafter, using the handler, the dummy wafer is removed from the stage and stored in the wafer holding shelf. Next, similarly, using the handler, the wafer to be weighed is taken out from the wafer holding shelf, placed on the stage, mass measurement is performed, and the measurement value is transmitted to the signal processing means. As described above, the mass measurement for the wafer to be processed and the dummy wafer can be executed by almost the same operation using the handler of the semiconductor manufacturing apparatus.

  Next, a method for calculating a change in the physical quantity of the wafer in the signal processing means will be described. First, the measurement of the aluminum film thickness in the process of forming an aluminum film on the wafer will be described. The mass of the wafer before film formation is M1, and the mass of the wafer after film formation is M2. Further, the surface area of the surface of the wafer on which the aluminum film is formed is S, and the aluminum density is ρ. The film thickness T of the formed aluminum is given by the following equation.

T = (M2−M1) / (S × ρ)
The signal processing means can calculate the film thickness of the aluminum coating formed on the wafer by performing arithmetic processing based on the above-described formula as a change in the physical quantity of the wafer.

As a specific example, when the density of aluminum is 2700 kg / m ³ and the diameter is 300 mm, the surface area of the wafer is S = (0.15) ² π (m ² ), When (M2-M1) = 0.1 × 10 -6 kg, the thickness of the aluminum becomes T = 0.52 nm.

  When a TiN film is formed on a semiconductor wafer having a diameter of 300 mm, the density is ρ = 5400 kg, and when (M 2 −M 1) = 0.1 mg, the film thickness T is T = 0.26 nm.

  Next, a method for calculating a polishing amount (a thickness of the polished wafer) in the polishing process as a physical quantity of the wafer will be described. The mass of the wafer before polishing is M1, and the mass of the wafer after polishing is M2. Further, the surface area of the polished surface of the wafer is S, and the silicon density is ρ2. The polishing thickness (polishing amount) P of the polished wafer is given by the following equation.

P = (M1−M2) / (S × ρ2)
Further, the film thickness of the silicon oxide film when a silicon oxide film is formed on the surface of the silicon wafer by thermal oxidation treatment will be described. The thermal oxidation process is represented by the following reaction formula.

Si + O ₂ → SiO ₂
Here, the molecular weight Msi of silicon is Msi = 28.09 g / mol, and the molecular weight (Msio) of SiO ₂ is Msio = 60.08 g / mol. The mass of SiO ₂ to be formed is represented by the following equation, where M1 is the wafer mass before processing and M2 is the wafer mass after processing.

(M1−M2) × {(Msio) / (Msio−Msi)}
Accordingly, the thickness T of the SiO ₂ film, when the density of the SiO ₂ film and [rho, is expressed by the following equation.

T = (M1−M2) × {(Msio) / (Msio−Msi)} / (S × ρ)
Here, the density of SiO ₂ [rho was ^{2210kg / m 3, (M1-} M2) = 0.1 When × ¹⁰ -6 kg, the mass of the silicon oxide film having a diameter formed on a silicon wafer of 300mm is 0. In the case of 1 mg, the film thickness T of the SiO ₂ film is T = 1.2 nm.

  That is, when a silicon oxide film is formed on a silicon wafer having a diameter of 300 mm by thermal oxidation, the film thickness can be managed with a resolution of 1.2 nm.

  Next, a change in film thickness due to etching will be described. When the surface area of the wafer is S, the ratio of the area to be etched is E, the density of the material to be removed is ρ, and the mass of the wafer before and after the etching is M1 and M2, the change in film thickness T is as follows: It is expressed by the following formula.

T = (M1−M2) / (S × E × ρ)
Therefore, when the area to be removed by the etching process is known, the etching depth can be measured by measuring the mass change of the wafer before and after the etching.

  Next, another embodiment of the process monitoring method according to the present invention will be described. FIG. 4 shows an embodiment in which a mass measuring device using a mass meter having a minimum display of 0.1 mg is incorporated in a production line. FIG. 4A is a perspective view showing a semiconductor manufacturing apparatus and a load port, and FIG. 4B is a diagram illustrating a transfer process until the semiconductor wafer is transferred from the load port to the semiconductor manufacturing apparatus. In addition, the same code | symbol is attached | subjected and demonstrated to the member same as the member used in FIG.1 and FIG.2. The semiconductor manufacturing apparatus 1 is provided with a first transfer chamber 10 as a front end module. Three load ports 2 a to 2 c are attached to the first transfer chamber 10. A measurement cassette 40 for measuring the mass of a semiconductor wafer to be processed is replaceably attached to the first load port 2a. The measurement cassette 40 has a container body that can be attached to a load port, and has a structure in which a mass meter 41 is incorporated in the container body. Then, the semiconductor wafer is mounted and removed from the mass meter by a handler provided in the semiconductor manufacturing apparatus. As the container body, for example, a FOUP container body can be used, and a mass meter can be incorporated in the FOUP container body. Measurement data output from the mass meter 41 is output to the signal processing circuit 6 via the signal line 42. A wafer to be processed is accommodated in a third load port 2c adjacent to the first load port 2a, and a wafer transfer container (FOUP) 43 for transferring a semiconductor wafer is mounted. The wafer transfer container 43 contains a semiconductor wafer that has been subjected to a predetermined process by the semiconductor manufacturing apparatus in the previous stage, and has been transferred along the manufacturing line.

  The semiconductor wafer accommodated in the wafer transfer container 43 that has arrived at the load port is taken out of the wafer transfer container 43 by the handler 12 disposed in the first transfer chamber 10, and is indicated by a broken line shown in FIG. Transport along. The handler 12 can be operated in the vertical direction, and can be two-dimensionally moved and rotated in a horizontal plane. The lid that closes the opening for taking in and out the wafer in the wafer transfer container 43 is opened by an opener, and the semiconductor wafer accommodated in the container is taken out by the handler 12. The semiconductor wafer taken out by the handler is transferred into the measurement cassette 40 and placed on the wafer stage of the mass meter. Then, mass measurement is performed, and after the measurement is completed, the handler 12 again takes out the measurement cassette 40 and transfers it to the semiconductor manufacturing apparatus 1.

  The wafer that has been subjected to a predetermined process in the semiconductor manufacturing apparatus is again operated by the handler 12 and transferred into the measurement cassette 40. And the mass after a process is measured. After the measurement, it is taken out from the measurement cassette by the handler 12 and transferred into the wafer transfer container 43. Thereafter, the next semiconductor wafer is taken out from the wafer transfer container 43, similarly weighed, and transferred to the semiconductor manufacturing 1. In this way, mass measurement and process processing are performed on all semiconductor wafers accommodated in the wafer transfer container 43, and after completion, the wafer transfer container is transferred to the next-stage semiconductor manufacturing apparatus.

  In the measurement cassette 40, a dummy wafer having a known calibration mass is arranged, the mass of the dummy wafer is measured before or after the mass measurement of the semiconductor wafer, and the measurement data is transmitted to the signal processing circuit. The data can be used for calibration.

  FIG. 5 is a flowchart for explaining the execution procedure of the process monitoring method shown in FIG. In step 1, a semiconductor manufacturing apparatus that accommodates a dummy wafer having substantially the same shape and mass as a semiconductor wafer to be measured in a measurement cassette in which a mass meter is incorporated, and performs process processing on the semiconductor wafer The first load port is replaceably mounted.

  Next, mass measurement and process processing are started in-line under the control of the controller. The wafer transfer container in which the semiconductor wafer to be measured is accommodated is transferred along the manufacturing line from the preceding semiconductor manufacturing apparatus, and is arranged at the second load port of the semiconductor manufacturing apparatus (step 2).

  The mass of the dummy wafer accommodated in the measurement cassette is measured, and the measurement data is transmitted to the signal processing means arranged outside via the signal line (step 3). The mass measurement of the dummy wafer can be performed as necessary.

  A dummy wafer is removed from the wafer stage by operating a handler provided in the semiconductor manufacturing apparatus (step 4).

  By operating the handler, the semiconductor wafer to be processed accommodated in the wafer transfer container is transferred into the measurement cassette (step 5).

The mass of the semiconductor wafer to be processed is measured, and the measurement data (first measurement data) is transmitted to the signal processing means (step 6).
By operating the handler, the semiconductor wafer to be processed is removed from the stage and transferred to the process chamber (step 7).

  Processing is performed in the process chamber (step 8).

  After the processing is completed, the processed semiconductor wafer is taken out of the process chamber by operating the handler and loaded into the measurement cassette (step 9).

  The mass after processing is measured for the processed semiconductor wafer, and the measured second measurement data is transmitted to the first signal processing means (step 10). If necessary, the dummy wafer can be subsequently subjected to mass measurement, and the measurement data can be transmitted to the signal processing means.

  In the signal processing means, the change in the physical quantity of the semiconductor wafer is calculated using the first and second measurement data and the measurement data for the dummy wafer (step 11). By performing these procedures under the control description of the controller, the change in the physical quantity of the semiconductor wafer in each process can be measured in-line.

  FIG. 6 is a view showing a modification of the mass measuring apparatus according to the present invention, FIG. 6 (A) is a diagram showing the upper side wall removed, and FIG. 6 (B) is a diagram showing it cut along a vertical plane. FIG. In addition, the same code | symbol is attached | subjected and demonstrated to the component same as the member used in FIG. In this example, a configuration is adopted in which calibration data is easily obtained using a dummy wafer. A cylinder 50 functioning as an elevating mechanism is attached to the upper side wall 20a of the container body 20. A support mechanism 52 for suspending and supporting the dummy wafer 51 is connected to the cylinder 50. The support mechanism 52 has three suspension arms 53a to 53c, and holding claws 54a to 54c for holding the dummy wafer 51 are provided at the tips of the suspension arms.

  The first cover 25 is formed with an opening through which three suspension arms can pass, so that the suspension arm can pass through the first cover. During the measurement of the semiconductor wafer, the cylinder 50 is positioned above, and the dummy wafer 51 is positioned above the semiconductor wafer 23 disposed on the wafer stage 24. Next, when the semiconductor wafer is removed from the wafer stage and the mass of the dummy wafer 51 is measured, the cylinder 50 is lowered by a predetermined distance. When the cylinder is lowered, the dummy wafer 51 is positioned on the wafer stage 24, and the engagement between the dummy wafer and the holding claws 54a to 54c formed at the tips of the suspension arms 53a to 53c is released. Mounted on the stage 24. In this state, the mass of the dummy wafer is measured. After the measurement is completed, the cylinder is raised, and the dummy wafer located on the stage is held in the middle of the measurement and moved upward by a predetermined distance. In this state, mass measurement of the next semiconductor wafer is performed. As described above, the dummy wafer can be easily mounted on the wafer stage by holding and transferring the dummy wafer using the suspension mechanism.

  The present invention is not limited to the above-described embodiments, and various modifications and changes can be made. For example, in the above-described embodiment, mass measurement is performed at an existing load port. It is also possible to measure the mass. In this case, the semiconductor wafer accommodated in the wafer transfer container transferred along the production line is transferred from the transfer container into the mass measurement unit by the handler of the semiconductor manufacturing apparatus, and its mass is measured. If comprised in this way, the mass measurement unit only for mass measurement can be provided in the position where the load port of a semiconductor manufacturing apparatus is arrange | positioned as needed. In the present invention, the concept of the measurement cassette attached to the first load port includes a mass measurement unit fixedly provided at the position of the load port of the semiconductor manufacturing apparatus.

It is a figure which shows an example of the semiconductor manufacturing system with which the process monitoring method by this invention is implemented. It is a figure which shows an example of a semiconductor manufacturing apparatus. It is a figure which shows an example of the conveyance container by this invention. It is a figure which shows the state in which the mass measuring apparatus by this invention was integrated in the manufacturing line. It is a flowchart which shows an example of the process monitoring method by this invention. It is a figure which shows the modification of the mass measuring device by this invention.

Explanation of symbols

1 Semiconductor Manufacturing Equipment 2a-2c Load Port
3a, 3c Wafer transfer container 4a-4c Stage 5a, 5c Signal line 6 Signal processing means 10 First transfer chamber 11a-11c Opener 12 First handler 13 Load lock chamber 14 Second transfer chamber 15 Second handler 16 Process chamber 17 Cooling chamber 18 Unload lock chamber 20 Container body 21 Lid 22 Mass meter unit 23, 31 Wafer 24 Wafer stage 25 First cover 26 Second cover 27 First signal line 28 Connector 29 Second signal line 30a-30c Wafer holding shelf 32 Dummy wafer

Claims (14)

A process monitoring method for monitoring a change in a physical quantity of a semiconductor wafer due to a semiconductor manufacturing process by measuring a change in mass of the wafer before and after the semiconductor manufacturing process,
A mass meter for measuring the mass of a semiconductor wafer to be processed is incorporated, and a measurement cassette that can be attached to a load port of a semiconductor manufacturing apparatus is prepared, and the measurement cassette is exchangeably attached to a load port of a semiconductor manufacturing apparatus. Process,
Storing the semiconductor wafer to be monitored in the measurement cassette;
Prior to the process, the mass of the semiconductor wafer is measured in a state where the measurement cassette is mounted on the load port, and the measured first measurement data is sent to the signal processing means arranged outside the measurement cassette. Sending, and
After the predetermined process is completed, a process of storing the processed semiconductor wafer in the measurement cassette;
Measuring the mass of the processed semiconductor wafer by the mass meter, and transmitting the measured second measurement data to the signal processing means;
A process monitoring method comprising: a step of calculating a change in a physical quantity of a semiconductor wafer before and after the processing by using the first measurement data and the second measurement data in the signal processing means.   2. The process monitoring method according to claim 1, wherein in a state where the measurement cassette is mounted on a load port of a semiconductor manufacturing apparatus, mounting of a semiconductor wafer on a mass meter using a handler provided in the semiconductor manufacturing apparatus and A process monitoring method, wherein desorption is performed. A process monitoring method for monitoring a change in a physical quantity of a semiconductor wafer due to a semiconductor manufacturing process by measuring a change in mass of the semiconductor wafer before and after the semiconductor manufacturing process at a load port provided in the semiconductor manufacturing apparatus,
A mass meter that measures the mass of the semiconductor wafer to be processed is built in, and a measurement cassette that can be attached to the load port of the semiconductor manufacturing apparatus is prepared. The measurement cassette can be replaced with the first load port of the semiconductor manufacturing apparatus. A process of attaching to,
Arranging a wafer transfer container in which one or a plurality of semiconductor wafers to be processed are accommodated and transferred along a semiconductor manufacturing line in a second load port adjacent to the first load port of the semiconductor manufacturing apparatus. When,
Using a handler provided in the semiconductor manufacturing apparatus, transferring the semiconductor wafer accommodated in the wafer transfer container into the measurement cassette;
Measuring the mass of the semiconductor wafer using a mass meter incorporated in the measurement cassette, and transmitting the measured first measurement data to signal processing means arranged outside the measurement cassette;
Using the handler, removing the mass-measured semiconductor wafer from the mass meter and transferring it to the processing chamber of the semiconductor manufacturing apparatus;
After the predetermined process is completed, a process of storing the processed semiconductor wafer in the measurement cassette;
Measuring the mass of the processed semiconductor wafer by the mass meter, and transmitting the measured second measurement data to the signal processing means;
A process monitoring method comprising: a step of calculating a change in a physical quantity of a semiconductor wafer before and after the processing by using the first measurement data and the second measurement data in the signal processing means.   4. The process monitoring method according to claim 1, wherein the measurement cassette holds a dummy wafer having substantially the same shape and substantially the same mass as a semiconductor wafer to be processed, and at least a process. Before or after the mass measurement of the wafer before processing, the dummy wafer is subjected to mass measurement, and the measured measurement data is transmitted to the signal processing means. The signal processing means includes the first and second signal processing means. A process monitor method for outputting a change in a physical quantity of a semiconductor wafer using measurement data and measurement data of a dummy wafer.   5. The process monitoring method according to claim 1, wherein a film forming process for forming a film on a surface of the semiconductor wafer is executed as a semiconductor manufacturing process for the semiconductor wafer, and the signal processing means includes: A process monitor method for outputting film thickness information of a film formed on the basis of a physical constant of a film material and a change in mass of a wafer before and after the film forming process.   5. The process monitoring method according to claim 1, wherein a silicon wafer is used as the wafer, a silicon oxide film forming process is performed by a thermal oxidation process as the semiconductor manufacturing process, and the signal processing unit includes: Using the first and second measurement data and the physical constants of silicon and silicon oxide, the process monitor method outputs the film thickness information of the formed silicon oxide film.   5. The process monitoring method according to claim 1, wherein an etching process is performed as the semiconductor manufacturing process, and the signal processing means is removed by the first and second measurement data and etching. A process monitor method for outputting depth information of an etched recess using a ratio of a region to be etched and a physical constant of a material to be etched.   5. The process monitoring method according to claim 1, wherein a polishing process for polishing a surface of a semiconductor wafer is performed as the semiconductor manufacturing process, and the signal processing means performs the first and second measurement. A process monitor method for outputting a polishing amount of a semiconductor wafer using data and a physical constant of a semiconductor wafer material.   9. The process monitor method according to claim 1, wherein the mass meter is capable of measuring the mass of the semiconductor wafer in a minimum display unit of 0.1 mg. A mass measurement method for measuring the mass of a semiconductor wafer in-line between various process steps,
Mounting a measurement cassette in which a mass meter for measuring the mass of a semiconductor wafer is incorporated in a first load port of a semiconductor manufacturing apparatus;
A wafer transfer container that contains one or a plurality of semiconductor wafers to be measured and is transferred along a semiconductor manufacturing line is arranged in a second load port adjacent to the first load port of the semiconductor manufacturing apparatus. Process,
Using a handler provided in the semiconductor manufacturing apparatus, transferring the semiconductor wafer accommodated in the wafer transfer container into the measurement cassette;
And measuring the mass of the semiconductor wafer using a mass meter incorporated in the measurement cassette and transmitting the measurement data to signal processing means arranged outside the cassette. Method. A mass measuring device for measuring the mass of a semiconductor wafer at a load port provided in a semiconductor manufacturing apparatus,
A container body that is replaceably attached to the load port and has an opening for taking in and out a semiconductor wafer to be measured;
A mass meter body that is disposed within the container body and measures the mass of the semiconductor wafer;
A wafer stage connected to the mass meter body and supporting the wafer to be measured so that its main surface is perpendicular to the vertical direction;
A dummy wafer having substantially the same shape as the semiconductor wafer to be measured and having a known mass in advance and a dummy wafer holding means for holding the dummy wafer;
A signal transmission means for transmitting a measurement value measured by the mass meter to a signal processing means arranged outside the container body,
A mass measuring apparatus, wherein when mounted on a load port, a semiconductor wafer to be measured is placed on the wafer stage by a handler of a semiconductor manufacturing apparatus. A mass measuring apparatus having a minimum display unit of 0.1 mg and suitable for measuring the mass of a semiconductor wafer,
A container body having an opening for taking in and out a semiconductor wafer;
A mass meter unit arranged in the container body and capable of measuring the mass of the semiconductor wafer in a minimum display unit of 0.1 mg;
A wafer stage connected to the mass meter unit and supporting the semiconductor wafer to be measured;
First and second covers arranged so as to be substantially parallel to the main surface of the semiconductor wafer, when the semiconductor wafer to be measured is placed on the wafer stage, spaced apart vertically so as to sandwich the wafer stage ,
A dummy wafer which is provided in the container body and has substantially the same shape as the semiconductor wafer to be measured and whose mass is known in advance and dummy wafer holding means for holding the dummy wafer;
A signal line for transmitting the measurement data measured by the mass meter unit to the outside of the container body,
The first and second covers include a thermally conductive conductive plate and a heat insulating member provided on the surface of the conductive plate.   13. The mass measuring apparatus according to claim 12, wherein when the semiconductor wafer to be measured is arranged on the stage, the first and second covers are the distance from the semiconductor wafer to the first cover and the second cover. The mass measuring device is set to be substantially equal to the distance.   14. The mass measuring apparatus according to claim 12 or 13, wherein the dummy wafer holding means includes elevating means attached to the container body, and holding means connected to the elevating means for holding the dummy wafer. A mass measuring apparatus, wherein a dummy wafer is placed on a wafer stage by lifting and lowering a gripping means, and the dummy wafer placed on the wafer stage is removed from the wafer stage.

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