Substrate processing system

A substrate processing system for performing a process with respect to a plurality of substrates includes an annular process chamber configured to accommodate the plurality of substrates and to perform a predetermined process on the plurality of substrates, a cassette mounting part configured to mount a cassette which accommodates the plurality of substrates, and a substrate transfer mechanism configured to transfer the plurality of substrates between the annular process chamber and the cassette mounting part. The plurality of substrates is concentrically disposed within the annular process chamber in a plane view.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-073450, filed on Mar. 31, 2014, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing system for performing a predetermined process with respect to a plurality of substrates.

BACKGROUND

For example, in a manufacturing process of a semiconductor device or the like, various kinds of processes such as an ion implantation process, an etching process, a film-forming process and the like are performed with respect to semiconductor wafers (hereinafter referred to as “wafers” as substrates. A process called an atomic layer deposition (ALD) or a molecular layer deposition (MLD), which performs a film-forming process with respect to wafers, is implemented by, for example, a batch processing system which performs a process with respect to a plurality of wafers within an evacuated process chamber.

As the batch processing system, there has been used a system disclosed in, for example, Patent Document 1. For example, as illustrated inFIG. 13, the batch processing system200includes, for example, a circular mounting table210configured to concentrically mount a plurality of wafers W thereon in order to assure the improvement of in-plane uniformity in a process of the wafers W and the improvement of uniformity in the process between the wafers W and a cylindrical process chamber211configured to accommodate the mounting table210,

A vacuum transfer chamber212is installed adjacent to the process chamber211. The wafers W accommodated within a cassette C of a cassette station201disposed at the atmospheric side a e transferred into the process chamber211through a load lock chamber214adjoining the vacuum transfer chamber212, by a transfer arm213disposed at the atmospheric side and a transfer arm215installed in e vacuum transfer chamber212.

PRIOR ART DOCUMENTS

Patent Documents

In the mounting table210on which the wafers W are concentrically mounted, as indicated by a broken line within the process chamber211inFIG. 13, a space A not mounted with the waters W is generated at the center of the mounting table210. The space A gradually increases as the number of the wafers W mounted on the mounting table10, namely the number of the wafers W accommodated within the process chamber211, grows larger. Thus, in the process chamber211illustrated inFIG. 13and which is configured to process the concentrically-mounted wafers W, the volume of the process chamber211required in processing one sheet of the wafer W (hereinafter referred to as a “required processing volume”) increases as the number of the wafers W to be processed becomes larger. Consequently, the volume of a space to be exhausted in order to process one sheet of the wafer W increases and, therefore, the time required in exhausting the interior of the process chamber211to a predetermined vacuum degree increases. As a result, there is posed a problem in that throughput of the wafer process is reduced.

For that reason, the number of the wafers W to be processed in the process chamber211is usually set at six so that the volume of the process chamber211per one wafer W should not become excessively large. A plurality of process chambers211configured in this way is installed adjacent to the vacuum transfer chamber212.

However, if the plurality of process chambers211is installed around the vacuum transfer chamber212, the vacuum transfer chamber212becomes larger, This poses a problem in that the footprint of the batch processing system200as a whole increases.

SUMMARY

Some embodiments of the present disclosure provide a substrate processing system for performing a predetermined process with respect to a plurality of substrates, which is capable of minimizing an increase in the volume of a process chamber attributable to an increase in the number of wafers W to be processed in the process chamber.

According to one embodiment of the present disclosure, there is provided a substrate processing system for performing a process with respect to a plurality of substrates, including: an annular process chamber configured to accommodate the plurality of substrates and to perform a predetermined process on the plurality of substrates; a cassette mounting part configured to mount a cassette which accommodates the plurality of substrates; and a substrate transfer mechanism configured to transfer the plurality of substrates between the annular process chamber and the cassette mounting part, wherein the plurality of substrates is concentrically disposed within the annular process chamber in a plane view.

According to the present disclosure, the annular process chamber is formed in an annular shape and the plurality of substrates is concentrically disposed within the annular process chamber. Thus, the above-described space that gradually increases along with the increase in the number of the accommodated substrates in the conventional cylindrical process chamber is not generated. Accordingly, even when the number of the substrates to be processed in the annular process chamber is increased, it is possible to suppress the increase in the volume of the process chamber to a minimum level.

According to the present disclosure, it is possible to provide a substrate processing system for performing a predetermined process with respect to a plurality of substrates, which is capable of minimizing an increase in the volume of an annular process chamber attributable to an increase in the number of wafers to be processed in the annular process chamber.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described. In the subject specification and the drawings, components having substantially identical functions and configurations will be designated by like reference numerals with the duplicate descriptions thereof omitted.FIG. 1is a plane view illustrating a schematic configuration of a wafer processing system1used as a substrate processing system according to one embodiment.FIG. 2is a vertical sectional view illustrating the schematic configuration of the wafer processing system1according to one embodiment. Descriptions will be made by taking, as an example, a case where, for example, semiconductor wafers are used as the wafers W of this embodiment and where so-called ALD for performing a film-forming process with respect to the wafers is implemented in the wafer processing system1.

As illustrated inFIG. 1, the wafer processing system1includes a cassette station2configured to load and unload a plurality of wafers W on a cassette-by-cassette basis, a processing station3configured to process the wafers W in, for example, a batch manner, and a control device4configured to control the process of the wafers W performed in the processing station3. The cassette station2and the processing station3are integrally connected to each other via load lock chambers5.

The cassette station2includes a cassette mounting part10and a transfer chamber11installed adjacent to the cassette mounting part10. A plurality of, e.g., three, cassettes C, each of which is capable of accommodating the plurality of wafers W, may be arranged on the cassette mounting part10in an X direction (in a left-right direction inFIG. 1). A wafer transfer arm12is installed in the transfer chamber11. The wafer transfer arm12is movable in an up-down direction and a left-right direction and is rotatable about a vertical axis (in θ direction). The wafer transfer arm12is configured to transfer the wafers W between the cassettes C of the cassette mounting part10and the load lock chambers5. InFIG. 1, there is illustrated a state in which one wafer transfer arm12is disposed in the transfer chamber11. However, the arrangement and installation number of the wafer transfer arm12are not limited to those of this embodiment but may be arbitrarily set.

The processing station3includes a substantially annul process chamber20configured to process the plurality of wafers W in a batch manner, and a vacuum transfer chamber21installed adjacent to the process chamber20in an internal space surrounded by the process chamber20. For example, as illustrated inFIG. 2, the width S of a cross section of the process chamber20is set larger than the diameter of the wafer W so that the process chamber20can horizontally accommodate the wafers W. A mounting table22on which the plurality of wafers W is mounted, is installed within the process chamber20. InFIG. 2, the cross section of the process chamber20is shown in a rectangular shape. However, the shape of the cross-section of the process chamber20is not limited to that of this embodiment but may be arbitrarily set as long as the annular mounting table22can be disposed within the process chamber20.

For example, as illustrated inFIG. 1, similar to the process chamber20, the mounting table22is formed in an annular shape and is disposed in a concentric relationship with the process chamber20. In the mounting table22, the plurality of wafers W is arranged on the same circumference along the circumferential direction of the mounting table22. InFIG. 1, there is illustrated astute in which, for example, fourteen wafers W are mounted on the mounting table22. However, the number of the wafers W and the size of the mounting table22may he arbitrarily set.

A drive mechanism23configured to horizontally rotate the mounting table22about the center axis of the mounting table22is installed, for example, on a lower surface of the mounting table22. The drive mechanism23is formed of, for example, a rotatable roller and the like. Lift pins (not shown) are embedded in the mounting table22so that the wafers W can be delivered between the lift pins and a wafer transfer mechanism40which will he described later.

For example, as illustrated inFIG. 2, an exhaust mechanism24is coupled to the process chamber20via an exhaust pipe25so that the interior of the process chamber20can be depressurized by the exhaust mechanism24. An adjustment valve26configured to adjust an amount of exhaust performed by the exhaust mechanism24is installed in the exhaust pipe25. For example, as illustrated inFIG. 3, gate valves27are installed at multiple points in a lateral surface of the process chamber20facing the vacuum transfer chamber21, namely between the process chamber20and the vacuum transfer chamber21. The gate valves27are kept closed in a normal state. By opening the gate valves27, it becomes possible to transfer the wafers W between the vacuum transfer chamber21and the process chamber20. InFIG. 3, there is illustrated a state in which the gate valves27are installed at three points at regular intervals. However, the arrangement and installation number of the gate valves27may be arbitrarily set. InFIG. 2, there is illustrated a state in which, for example, the exhaust pipe25is connected to the lateral surface of the process chamber20at one point. However, from the viewpoint of uniformly exhausting the interior of the process chamber20and preventing occurrence of an uneven flow, it is desirable that exhaust pipes25are installed in the process chamber20at multiple points.

A gas supply mechanism30configured to supply a predetermined process gas into the process chamber20is coupled to, for example, a ceiling surface of the process chamber20, via a gas supply pipe31. A flow rate adjustment mechanism32configured to adjust a supply amount of a process gas is installed in the gas supply pipe31. InFIG. 2, there is illustrated a state in which, for example, the gas supply pipe31is connected to the ceiling surface of the process chamber20at one point. However, from the viewpoint of uniformly supplying the process gas into the process chamber20and uniformly performing a wafer process, it is desirable that, similar to the case of the exhaust pipes25, gas supply pipes31are installed in the process chamber20at multiple points. Furthermore, the connection point of the gas supply pipe31is not limited to the ceiling surface of the process chamber20but may be the lateral surface of the process chamber20or the like. In particular, there may be a case where a plasma source configured to introduce plasma for assisting a film-forming process on the wafers W into the process chamber20is disposed on the top surface or the lateral surface of the process chamber20. Accordingly, the arrangement of devices at the outer side of the process chamber20may be arbitrarily set depending on the contents of the process performed by the wafer processing system1.

For example, as illustrated inFIG. 2, the load lock chambers5are disposed under the process chamber20. In other words, the load lock chambers5are disposed across the lower side of the process chamber20in a plane view The load lock chambers5interconnect the vacuum transfer chamber21and the transfer chamber11. Gate valves (not shown) are installed between the load lock chambers5and the transfer chamber11and between the load lock chambers5and the vacuum transfer chamber21. By opening the gate valves during the transfer of the wafers W, it is possible for the wafers W to pass through the respective load lock chambers5.

An upper portion of the vacuum transfer chamber21is connected to the process chamber20through the gate valves27and a lower portion of the vacuum transfer chamber21is connected to the load lock chambers5through the gate valves (not shown). Thus, the vacuum transfer chamber21extends downward from, for example, the bottom surface of the process chamber20. The bottom surface of the vacuum transfer chamber21is substantially flush with the bottom surfaces of the load lock chambers5. InFIG. 2, there is illustrated a state in which the load lock chambers5are installed under the process chamber20. However, for example, as illustrated inFIG. 4, the load lock chambers5may be installed above the process chamber20. In other words, the load lock chambers S may be disposed across the upper side of the process chamber20in a plane view.

Similar to the process chamber20an exhaust mechanism (not shown) is connected to the vacuum transfer chamber21. The interior of the vacuum transfer chamber21can be depressurized by the exhaust mechanism. A wafer transfer mechanism40configured to transfer the wafers W between the load lock chambers S and the process chamber20is installed within the vacuum transfer chamber21.

The wafer transfer mechanism40includes a plurality of swingable and extendible articulated transfer arms41. The respective transfer arms41are supported by a support member42installed, for example, in the central portion of the vacuum transfer chamber21to extend in the vertical direction. Furthermore, the respective transfer arms41are configured so that they can be moved up and down along the support member42by an elevator mechanism (not shown). The respective transfer arms41can transfer the wafers W between the load lock chambers5and the process chamber20. InFIG. 1, there is illustrated a state in which, for example, three transfer arms41are installed. However, the installation number of the transfer arms41may be arbitrarily set. The configuration of the wafer transfer mechanism40is not limited to that of this embodiment. A structure and type of the wafer transfer mechanism40may be arbitrarily set as long as the wafer transfer mechanism40can transfer the wafers W between the load lock chambers S and the process chamber20.

The control device4is, for example, a computer, and includes a program storage part (not shown). A program for controlling the process of the wafers W in the wafer processing system1is stored in the program storage part. This program is recorded in a computer-readable recording medium such as, e.g., a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magneto-optical disk (MO) or a memory card, and may be installed in the control device4from the recording medium.

The wafer processing system1according to this embodiment is configured as above. Next, descriptions will be made on the wafer process performed by the wafer processing system1.

When processing the wafers W, a plurality of unprocessed wafers W is first taken out from the respective cassette C of the cassette station2by the wafer transfer arm12and is sequentially transferred into the respective load lock chamber5. Thereafter, the interior of the load lock chamber5is exhausted and depressurized to a predetermined pressure.

Subsequently, the gate valves (not shown) existing between the load lock chamber5and the vacuum transfer chamber21whose interior is kept in a depressurized state in advance, are opened and the wafers W existing within the load lock chamber5are sequentially loaded into the process chamber20which is kept in a depressurized state in advance, via the vacuum transfer chamber21by the transfer arms41of the wafer transfer mechanism40.

The wafers W transferred into the process chamber20are sequentially mounted on the mounting table22by way of the lift pins (not shown).

If all the wafers W are loaded into the process chamber20, the gate valves27are closed and the process of the wafers W is implemented by the control device4. When processing the waters W, the interior of the process chamber20is depressurized to a predetermined pressure by the exhaust mechanism24. At this time, the exhaust process is rapidly performed because the process chamber20is formed in an annular shape, in the conventional cylindrical process chamber211, it is necessary to perform an exhaust process with respect to the space A illustrated inFIG. 13. The space A increases in proportion to the increase in the number of the wafers W disposed within the process chamber211. Since the diameter of the space A increases along with the increase in the number of the wafers W, the volume of the process chamber211required in processing one wafer W (“required processing volume”) gradually increases in proportion to the square of the radius of the space A. For that reason, the volume of the process chamber211does not linearly increases but progressively increases, for example, as indicated by a line P inFIG. 5. Accordingly, there is posed a problem in that the time required in exhausting the interior of the process chamber211increases along with the increase in the number of the wafers W. The horizontal axis inFIG. 5indicates the installation number of the wafers W and the vertical axis indicates the internal volume of the process chamber. In addition,FIG. 5is directed to a case where the diameter of each of the wafers W is 300 mm.

On the other hand, in the process chamber20of this embodiment, when increasing the number of the wafers W disposed within the process chamber20, it is only necessary to enlarge the diameter R of the process chamber20illustrated inFIG. 2while keeping the width S of the process chamber20constant. In other words, even if the number of the wafers W disposed within the process chamber20is increased, the required processing volume in the process chamber20, for example, the volume of the space B hatched inFIG. 6, is kept constant. Thus, for example, when increasing the number of the wafers W by one, it is only necessary to increase the volume of the process chamber20just as much as the space B corresponding to one wafer. There is not generated a phenomenon that, as is the case in the conventional process chamber211, the volume of the process chamber211increases along with the change in the diameter of the space A. As a result, the volume of the process chamber20linearly increases along with the increase in the number of the wafers W as indicated by a line Q inFIG. 5. Accordingly, even if the number of the wafers W disposed within the process chamber20is increased, it is possible to significantly shorten the exhaust time as compared with the conventional process chamber211. More specifically, for example, as illustrated inFIG. 5, when a process chamber20capable of accommodating twelve wafers W is provided, it is possible for the conventional process chamber211to accommodate only eight wafers W in the same volume. Thus, the exhaust time required per one wafer becomes longer.

If the interior of the process chamber20is depressurized to a predetermined pressure, a specified process gas is supplied from the gas supply mechanism30, whereby a film-forming process is performed with respect to the wafers W Since the required processing volume of the process chamber20of this embodiment is smaller than that of the conventional process chamber211as described above, it is possible to reduce a flow rate of the process gas supplied to process one wafer W. It is also possible to reduce the running cost of the wafer processing system1. If the film-forming process performed within the process chamber20is completed, the gate valves27are opened. Subsequently, the processed wafers W are sequentially unloaded from the process chamber20into the vacuum transfer chamber21by the transfer arms41of the wafer transfer mechanism40. Thereafter, the wafers W are sequentially accommodated within the respective cassette C of the cassette station2via the respective load lock chamber5. If all the wafers W are accommodated within the respectively cassette C, the respective cassette C is transferred outside the cassette station2. A new cassette C accommodating unprocessed wafers W is transferred to the cassette station2. Then, the unprocessed wafers W are sequentially transferred to the process chamber20so that a series of processes described above are repeated.

According to the above embodiments, the process chamber20is formed in an annular shape and the wafers W are concentrically disposed within the process chamber20. Thus, there is no phenomenon that, as is the case in the conventional cylindrical process chamber211, the space A gradually increases along with the increase in the number of the wafers W accommodated. Accordingly, even if the number of the waters W processed in the process chamber20is increased, it is possible to suppress the increase in the volume of the process chamber20to a minimum level.

Furthermore, in the conventional batch processing system200, if the installation number of the process chambers211is increased, the vacuum transfer chamber21installed outside the process chambers211needs to be enlarged along with the increase in the number of the transfer arms215. For that reason, the footprint increases not only due to the increase in the number of the process chambers211but also due to the enlargement of the vacuum transfer chamber212.

In contrast, in this embodiment, the vacuum transfer chamber21is installed in the space defined inside the annular process chamber20. The increase in the footprint of the wafer processing system1can be suppressed to only the increase in the size of the process chamber20. That is to say, the increase in the footprint with respect to the process number of the wafers W in the wafer processing system1of this embodiment becomes substantially linear if there is no change in the size of the cassette station2or the load lock chambers5which is the transfer system installed outside the vacuum transfer chamber21. Thus, according to this embodiment, it is possible to increase the process number of the wafers W per the same footprint as compared with the related art.

Furthermore, in the conventional batch processing system200and the wafer processing system1according to this embodiment if it is assumed that the configurations of the cassette stations2and201or the configurations of the load lock chambers5and214are substantially identical with each other, the footprint F (indicated by a dashed line inFIG. 7) of the wafer processing system1of this embodiment illustrated inFIG. 7falls within such a region that substantially covers the cassette station201, the load lock chambers214and the vacuum transfer chamber212of the conventional batch processing system200, for example, as illustrated inFIG. 8. According to the study of the present inventors, it was confirmed that, for example, when twelve wafers W are processed in a batch manner by the wafer processing system1, the footprint of the wafer processing system1according to this embodiment can be reduced by about 30% as compared with the footprint of the conventional batch processing system200.

Furthermore, in the wafer processing system I according to this embodiment, the load lock chambers5are installed across the upper side or the lower side of the process chamber20. It is therefore possible to reduce the footprint even in the area where the load lock chambers5and the process chamber20overlap with each other in a plane view.

While in the above embodiments, the vacuum transfer chamber21has been described to be disposed inside the annular process chamber20, the vacuum transfer chamber21need not be necessarily installed inside the process chamber20, because it is only necessary to form the process chamber20in an annular shape from the viewpoint of not increasing the required processing volume of the process chamber20. In this case, the gate valves27may be installed outside the process chamber20.

In the case where the vacuum transfer chamber21is installed inside the process chamber20, the transfer arms41can gain access to the gate valves27even if the gate valves27are installed at any position inside the process chamber20. In other words, if the vacuum transfer chamber21is installed inside the process chamber20, it is possible to freely set the positions of the gate valves27. Accordingly, it is preferable to install the vacuum transfer chamber21inside the process chamber20. In particular, by disposing the wafer transfer mechanism40at the center of the vacuum transfer chamber21, the distances from the respective transfer arms41to the process chamber20become equal to one another. Thus, the transfer delay due to the difference in the transfer distance does not occur. It is therefore easy to manage the transfer time of the wafers W. In addition, the number of the wafers W transferred per unit time can he increased as the installation number of the transfer arms41increases.

While in the above embodiments, the water processing system1has been described to include the single process chamber20, a plurality of process chambers20may be installed in the wafer processing system1. For example, when two process chambers20are installed, as illustrated inFIG. 9, the two process chambers20may be installed so as to interpose the cassette station2between the two process chambers20, namely at the opposite sides of the cassette station2. By doing so, it is possible to suppress the increase in the footprint to a minimum level. InFIG. 9, the transfer chamber11is installed common to the two process chambers20and the cassette station2is configured so that the cassettes C are disposed at the lateral sides of the transfer chamber11. Other configurations are the same as the configurations described above.

On the other hand, if the process chambers211are disposed at the opposite sides of the cassette station2in the conventional batch processing system200, the footprint is significantly increased. As an example,FIG. 10illustrates the conventional batch processing system200in which the process chambers211are disposed at the opposite sides of the cassette station2. The region indicated by a dashed line inFIG. 10is the footprint F of the wafer processing system1illustrated inFIG. 9, In this way, by using the process chamber20according to this embodiment, it is possible to suppress the increase in the footprint attributable to the increase in the processing number of the wafers W to a minimum level.

While in the above embodiments, the load lock chambers5have been described to be disposed at one of the upper and lower side of the process chamber20, the present disclosure is not limited thereto. In some embodiments, as illustrated inFIG. 11, two load lock chambers5aand5bmay be disposed at the upper and lower side of the process chamber20so as to extend across the upper and lower side of the process chamber20. In this case, the vacuum transfer chamber21may be installed at a height where the wafers W can be transferred to both the load lock chambers5aand5b.In general, it is sometimes the case that the transfer speed between the vacuum transfer chamber21and the cassette C is limited in the load lock chamber5. By disposing the load lock chambers5aand5bat multiple stages in the up-down direction as illustrated inFIG. 11, it is possible to eliminate the load lock chambers from becoming a bottleneck.

WhileFIG. 11illustrates a case where the load lock chambers5are installed at multiple stages, the process chambers20may also be disposed at multiple stages in the up-down direction, for example, as illustrated inFIG. 11Even in such a case, the vacuum transfer chamber21may be installed at a height corresponding to the number of stages of the process chambers20installed in the up-down direction In this way, by installing the process chambers20at multiple stages in the up-down direction, it is possible to improve throughput of the process of the waters W in the wafer processing system1without increasing the footprint of the wafer processing system1.

While in the above embodiments, there has been described, by way of example, a case where the batch process of collectively processing the plurality of wafers W within the process chamber20is performed, the application of the process chamber according to this embodiment is not limited to such a batch process. As an example, the present disclosure may be applied to a single-wafer-type wafer processing system in which the interior of the process chamber20is partitioned for each space B illustrated inFIG. 6and the process of the wafers W is individually performed in each space B. Furthermore, the present disclosure may be applied to a wafer processing system in which two or more wafers W are simultaneously processed in a space formed by interconnecting two or more spaces B, namely a wafer processing system in which, for example, a plurality of adjoining spaces B is interconnected and defined into a single space and in which a plurality of wafers W is simultaneously processed in the space thus defined.

While the preferred embodiment of the present disclosure has been described with reference to the accompanying drawings, the present disclosure is not limited to the aforementioned embodiment. It is clear that a person having an ordinary knowledge in the relevant art will be able to conceive various kinds of changes and modifications within the spirit of the present disclosure defined in the claims. It is to be understood that these changes and modifications may well fall within the scope of the technical scope of the present disclosure. The present disclosure is not limited to the aforementioned embodiment but may employ different forms. In addition, the present disclosure may be applied not only to a film-forming process performed in a processing apparatus but also other processes, for example, an etching process.

EXPLANATION OF REFERENCE NUMERALS