Semiconductor manufacturing apparatus with supporting columns and tables

In one embodiment, a semiconductor manufacturing apparatus includes a container to contain wafers, and supporting tables provided in the container so as to be stacked on one another, and each including a supporting face that comes into contact with a wafer to support the wafer. The apparatus further includes supporting columns to join the supporting tables together and provided at positions where the supporting columns are contained inside outer circumferences of the supporting tables. The apparatus further includes a gas feeder to feed a gas to the wafers on the supporting tables, and a gas discharger to discharge the gas fed to the wafers on the supporting tables. Each of the supporting tables includes a first upper face as the supporting face, and a second upper face provided so as to surround the first upper face at a level higher than a level of the first upper face.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2017-167818, filed on Aug. 31, 2017, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments disclosed herein relate to a semiconductor manufacturing apparatus, a wafer conveying apparatus and a wafer conveying method.

BACKGROUND

In a batch processing apparatus that simultaneously processes a plurality of wafers with a gas, the gas is required to flow appropriately. Specifically, when the gas flows from a gas feeder to a gas discharger, it is not desirable for the gas to flow around the wafers, and it is desirable for the gas to mostly flow between the wafers. Moreover, when the gas to be fed to a certain wafer flows to another wafer, there is a risk that unevenness in processing between the wafers arises.

DETAILED DESCRIPTION

In one embodiment, a semiconductor manufacturing apparatus includes a container configured to contain a plurality of wafers, and a plurality of supporting tables provided in the container so as to be stacked on one another, and each including a supporting face that comes into contact with a wafer to support the wafer. The apparatus further includes a plurality of supporting columns configured to join the supporting tables together and provided at positions where the supporting columns are contained inside outer circumferences of the supporting tables. The apparatus further includes a gas feeder configured to feed a gas to the wafers on the supporting tables, and a gas discharger configured to discharge the gas fed to the wafers on the supporting tables. Moreover, each of the supporting tables includes a first upper face as the supporting face, and a second upper face provided so as to surround the first upper face at a level higher than a level of the first upper face.

First Embodiment

FIG. 1is a cross-sectional view schematically showing a structure of a semiconductor manufacturing apparatus of a first embodiment.

The semiconductor manufacturing apparatus inFIG. 1includes a reactor11which is an example of a container, a plurality of boats12which are an example of a plurality of supporting tables, a plurality of supporting columns13, a pedestal14, a gas feeder15and a gas discharger16. The semiconductor manufacturing apparatus inFIG. 1is a cross-flow batch processing apparatus which simultaneously processes a plurality of wafers1with a gas, for example, a chemical vapor deposition (CVD) apparatus or an atomic layer deposition (ALD) apparatus.

The reactor11includes an inner tube11awhich contains the plurality of wafers1, and an outer tube11bwhich contains the inner tube11a. The inner tube11aand the outer tube11bare an example of glass tubes.FIG. 1shows an X-direction and a Y-direction which are parallel to surfaces of these wafers1and perpendicular to each other, and a Z-direction perpendicular to the surfaces of these wafers1. In the present specification, the +Z-direction is handled as the upward direction and the −Z-direction is handled as the downward direction. Nevertheless, the −Z-direction may coincide with the direction of gravity or may not coincide therewith.

Each boat12has a supporting face that comes into contact with the wafer1to support the wafer1, and the wafer1is placed on the supporting face. Each boat12has an annular shape having an outer circumference E1and an inner circumference E2, and has an opening12aenclosed by the inner circumference E2. Moreover, each boat12has a first upper face S1which is the supporting face, and a second upper face S2provided so as to surround the first upper face S1at a higher level than that of the first upper face S1. A level difference exists between the first upper face S1and the second upper face S2. In the present embodiment, the plurality of boats12are installed in the inner tube11aso as to be stacked on one another. These boats12are formed, for example, of quartz.

Each supporting column13joins the boats12together, and is provided at a position where it is contained inside the outer circumferences E1of these boats12. Specifically, each supporting column13is provided at a position where it is contained between the outer circumferences E1and the inner circumferences E2of these boats12. Therefore, as these boats12are observed from the above, all the supporting columns13are hidden under the boats12, and do not protrude from the outer circumferences E1or the inner circumferences E2of the boats12. These supporting columns13are formed, for example, of quartz.

Each supporting column13joins adjacent boats12together and does not penetrate these boats12. Specifically, each supporting column13is welded onto a lower face of one boat12and an upper face of the other boat12. Nevertheless, each supporting column13may join a plurality of boats12together by penetrating one or more boats12. As mentioned later, adjacent boats12of the present embodiment are joined together by three supporting columns13.

The pedestal14supports a boat structure composed of these boats12and supporting columns13, and rotates the boat structure around a rotational axis A shown inFIG. 1.

The gas feeder15is disposed between the inner tube11aand the outer tube11band includes gas feeding ports P1that feed gas to the wafers1on the boats12. The gas feeding ports P1are provided for the individual boats12in order to feed gas onto surfaces of the wafers1.

The gas discharger16is disposed between the inner tube11aand the outer tube11band includes a gas discharge port P2that discharges the gas fed to the wafers1on the boats12.

FIG. 1schematically shows the shapes and the arrangements of these components as needed for easy understanding of the description of these components. For example,FIG. 1shows components on the same cross section, which components do not appear on the same cross section in the strict sense. More correct shapes and arrangements of such components are mentioned later with reference toFIGS. 2A to 3.

FIGS. 2A and 2Bare perspective views showing the boat structure of the semiconductor manufacturing apparatus of the first embodiment.

FIG. 2Aexemplarily shows three boats12and a plurality of supporting columns13which join these boats12together. Each supporting column13is provided at a position where it is contained between the outer circumferences E1and the inner circumferences E2of these boats12.

FIG. 2Bexemplarily shows a state where wafers1are placed on these boats12. Since a diameter of the inner circumference E2of the boat12is set to be smaller than a diameter of the wafer1, the opening12aof the boat12is covered by the wafer1. As mentioned later, the opening12ais used when the wafer1is elevated.

FIG. 3is a cross-sectional view showing the structure of the semiconductor manufacturing apparatus of the first embodiment.FIG. 3shows a cross section taken along the B-B′ line shown inFIG. 1. Meanwhile,FIG. 1shows a cross section taken along the C-C′ line shown inFIG. 3.

The gas feeder15includes first and second injectors15aand15bthat feed gas to the wafer1from the gas feeding ports P1. For example, the first injector15ais used for feeding first source gas. The second injector15bis used for feeding second source gas different from the first source gas. The gas feeding port P1is an example of a nozzle that ejects gas.

The gas discharger16includes first and second gas discharging tubes16aand16bfor discharging the gas fed to the wafer1from the gas discharging port P2. An arrow G1schematically shows a flow of gas above the wafer1.

Sign W1denotes a distance (clearance) between the outer circumference E1of the boat12and an inner wall of the reactor11. The inner wall of the reactor11of the present embodiment is formed of an inner circumferential face of the inner tube11a.

The supporting columns13of the present embodiment are provided at positions where they are contained inside the outer circumference E1of the boat12, and do not protrude outside the outer circumference E1. Therefore, the clearance W1can be set to be short. Thereby, gas flowing around the wafer1can be reduced, and the gas can be mostly caused to flow between the wafers1as indicated by the arrow G1. Furthermore, gas to be fed to a certain wafer1can be suppressed from flowing in toward another wafer1. As above, according to the present embodiment, gas can be appropriately fed to the wafers1, and unevenness in processing between the wafers1can be reduced.

Gas from the gas feeder15is ideally desirable to flow entirely between the wafers1. Hence, in the present embodiment, the clearance W1is set to be short. For example, it is desirable for 90% or more of gas from the gas feeder15to flow between the wafers1. According to an experiment, when the clearance W1is 10 mm or less, 90% or more of gas flows between the wafers1. Therefore, the clearance W1of the present embodiment is set to be 10 mm or less.

FIG. 4is a cross-sectional view showing a structure of a semiconductor manufacturing apparatus according to a comparative example of the first embodiment.

The supporting columns13of the comparative example are not provided at positions where they are contained inside the outer circumference E1of the boat12but protrude outside the outer circumference E1. Therefore, a clearance W2cannot be set to be short. As a result, not only much gas from the gas feeder15flows between the wafers1as indicated by the arrow G1, but also much gas results in flowing around the wafers1as indicated by an arrow G2. The gas on the arrow G2flows in toward another wafer1, which causes unevenness in processing between the wafers1.

On the other hand, according to the present embodiment, a flow of gas as indicated by the arrow G2can be reduced. The semiconductor manufacturing apparatus of the present embodiment is useful, for example, in the case where a wafer1large in surface area and a wafer1small in surface area are simultaneously processed. The former wafer1is an example of a wafer for manufacturing a memory with a three-dimensional structure. The latter wafer1is an example of a dummy wafer for monitoring a state inside the reactor11. In such a case, a flow of gas as indicated by the arrow G2tends to cause unevenness in processing between the wafers1in the vicinity of the dummy wafer. According to the present embodiment, a flow of gas as indicated by the arrow G2, however, can be reduced, which can reduce such unevenness.

Since in the present embodiment, the supporting columns13are positioned inside the outer circumference E1of the boat12, there is a risk that it is difficult for the wafer1to be placed on the boat12. Therefore, the semiconductor manufacturing apparatus of the present embodiment includes a wafer conveying apparatus having a structure with which the wafer1can be easily placed on such a boat12. Hereafter, details of the wafer conveying apparatus are described.

FIGS. 5A to 5Dare perspective views and cross-sectional views showing a structure of the wafer conveying apparatus of the first embodiment.

FIG. 5AandFIG. 5Bare a perspective view and a cross-sectional view showing a lifting arm21constituting the wafer conveying apparatus, respectively. The lifting arm21can elevate and lower the wafer1in the reactor11. The lifting arm21is an example of a second arm. A conveying arm22mentioned later is an example of a first arm.

The lifting arm21is constituted of a lower plate21aand an upper plate21b. The upper plate21bis placed on the lower plate21a.FIG. 5CandFIG. 5Dare perspective views showing shapes of the upper plate21band the lower plate21a, respectively. The upper plate21bcan slide along a groove R provided in the lower plate21a. The upper plate21bhas a plurality of (herein, three) linear parts. While the groove R has substantially the same shape as that of the upper plate21b, it has a slightly larger size than the upper plate21bsuch that the upper plate21bcan slide therein. The lower plate21ais an example of a first plate. The upper plate21bis an example of a second plate.

FIGS. 6A to 6Care a perspective view and cross-sectional views for explaining operation of the wafer conveying apparatus of the first embodiment.

When the upper plate21bshown inFIG. 5AandFIG. 5Bslides relative to the lower plate21ain the −X-direction, the shape of the upper plate21bchanges as inFIG. 6AandFIG. 6B. Specifically, when the upper plate21bslides in the −X-direction, the tips of the upper plate21babut against the tips of the groove R, and the tips of the upper plate21bare deformed so as to be bent as indicated by sign K. In this stage, when the wafer1exists above the tips of the upper plate21b, the tips of the upper plate21bcome into contact with the wafer1to elevate the wafer1. This is referred to as lift-up of the wafer1. Meanwhile, when the upper plate21bslides in the +X-direction, the bending of the tips of the upper plate21bis relieved, so that the wafer1is lowered.

In the present embodiment, as shown inFIG. 6C, a hinge21cmay be disposed between the tip of the upper plate21band the tip of the groove R. In this case, when the upper plate21bslides in the −X-direction, the hinge21cis pushed between the tip of the upper plate21band the tip of the groove R, and the hinge21cis deformed to close. In this stage, when the wafer1exists above the hinge21c, the hinge21ccomes into contact with the wafer1to elevate the wafer1. Meanwhile, when the upper plate21bslides in the +X-direction, the hinge21ccloses, so that the wafer1is lowered. The hinge21cis an example of a member positioned between the first plate and the second plate.

FIGS. 7A to 8Care perspective views showing an operation example of the wafer conveying apparatus of the first embodiment.FIGS. 7A to 8Cshow processes through which one wafer1is conveyed on an arbitrary boat12in the reactor11. This boat12is an example of a first supporting table. This wafer1is an example of a first wafer.

First, the lifting arm21moves to a lower region of the boat12(FIG. 7A). Specifically, the lifting arm21moves such that the tips of the upper plate21band the tips of the groove R are positioned below the opening12a.

Next, the conveying arm22retains the wafer1to move to an upper region of this boat12(FIG. 7B). The conveying arm22has a plurality of (herein, two) linear parts for retaining the wafer1.

Next, the upper plate21bslides relative to the lower plate21ain the −X-direction, and thereby, the tips of the upper plate21bare deformed (FIG. 7C). As a result, the tips of the upper plate21bcome into contact with the wafer1via the opening12aof the boat12to elevate the wafer1(lift-up). Accordingly, the wafer1is brought into a state of being retained by the lifting arm21in place of the conveying arm22.

After completion of the lift-up of the wafer1, the conveying arm22is retracted from the upper region of the boat12(FIG. 8A).

Next, the upper plate21bslides relative to the lower plate21ain the +X-direction, and thereby, the deformation of the tips of the upper plate21bis relieved (FIG. 8B). As a result, the wafer1is lowered to be placed on the boat12.

After completion of the placement of the wafer1, the lifting arm21is retracted from below the boat12(FIG. 8C).

As above, the wafer conveying apparatus of the present embodiment places the wafer1on the boat12with the lifting arm21and the conveying arm22. Thereby, the wafer1can be conveyed even when a space where the wafer conveying apparatus can move in the reactor11is small. In the semiconductor manufacturing apparatus of the present embodiment, the supporting columns13are positioned inside the outer circumferences E1of the boats12, which reduces the space where the wafer conveying apparatus can move. Therefore, this sort of wafer conveying apparatus is useful. According to the present embodiment, even in such a case, the wafer1can be appropriately conveyed.

In the present embodiment, the lifting arm21moves from a place in the +X-direction of the boat12to a place below the boat12, and the conveying arm22moves from a place in the −Y-direction of the boat12to a place above the boat12. Nevertheless, the lifting arm21and the conveying arm22may move from other places to the places below and above the boat12, respectively. For example, when the lifting arm21moves from the place in the +X-direction of the boat12to the place below the boat12, the conveying arm22may move from a place in the −X-direction of the boat12to the place above the boat12.

Moreover, while the opening12aof the present embodiment is circular, it may have another shape as long as the tips of the upper plate21bcan come into contact with the wafer1to elevate the wafer1.

Moreover, the thickness of the lifting arm21may be arbitrarily set as long as the lifting arm21can be inserted between the boats12without the tips of the upper plate21bdeformed. Likewise, the thickness of the conveying arm22may be arbitrarily set as long as the conveying arm22can be inserted between the boats12.

Furthermore, the wafer conveying apparatus of the present embodiment may include a single lifting arm21or may include a plurality of lifting arms21. In the former case, the wafer conveying apparatus sequentially lifts up the plurality of wafers1. In the latter case, the wafer conveying apparatus simultaneously lifts up a plurality of wafers1. Likewise, the wafer conveying apparatus of the present embodiment may include a single conveying arm22or may include a plurality of conveying arms22.

FIG. 9is a schematic diagram showing a configuration of the wafer conveying apparatus of the first embodiment.

As shown inFIG. 9, the wafer conveying apparatus of the present embodiment includes the lifting arm21, the conveying arm22, a first driver23, a second driver24, a third driver25and a controller26.

The first driver23is a mechanism that operates the lifting arm21. For example, it moves the lifting arm21as inFIG. 7A, and retracts the lifting arm21as inFIG. 8C.

The second driver24is a mechanism that slides the upper plate21brelative to the lower plate21a. For example, it slides the upper plate21bin the −X-direction as inFIG. 7C, and slides the upper plate21bin the +X-direction as inFIG. 8B.

The third driver25is a mechanism that operates the conveying arm22. For example, it moves the conveying arm22as inFIG. 7B, and retracts the conveying arm22as inFIG. 8A.

The first driver23is constituted, for example, of a motor and a mechanism that transmits power from the motor to the lifting arm21. The same holds true for the second and third drivers24and25. The first to third drivers23to25may be constituted of different motors or may be constituted of the same motors.

The controller26controls operation of the lifting arm21and the conveying arm22through control of the first to third drivers23to25. The operation of the lifting arm21and the conveying arm22inFIGS. 7A to 8Cis controlled by the controller26. The controller26is an example of a processor, a controlling circuit, a computer or the like. The controller26may be the same as a controller that controls the whole semiconductor manufacturing apparatus or may be separate from the controller controlling the whole semiconductor manufacturing apparatus.

As above, the supporting columns13of the present embodiment are provided at positions where they are contained inside the outer circumferences E1of the boats12. Therefore, according to the present embodiment, the clearance W1between the outer circumferences E1of the boats12and the inner wall of the reactor11can be made short, which enables gas to be appropriately fed to the wafers1.

Moreover, the wafer conveying apparatus of the present embodiment places the wafer1on the boat12with the lifting arm21and the conveying arm22. Therefore, according to the present embodiment, the wafers1can be appropriately conveyed even when a structure in which the clearance W1is short is employed.