JPH0719149Y2 - Double fork horizontal carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a wafer transfer device in a device in which a wafer is horizontally placed on a susceptor and vapor deposition, etching, sputtering, vapor deposition, and the like are performed.

(B) Prior Art A vapor phase growth apparatus and its carrying apparatus will be described with reference to FIG.

Inside the growth chamber 1, there is a wafer 6 mounted on a susceptor 4. Below the growth chamber 1 is a sample exchange chamber 7.
A load lock chamber 3 is provided on the side of the sample exchange chamber 7, and a gate valve 2 is provided between the two to open and close freely.

A high frequency coil 8 for heating the susceptor 4 and the wafer 6 is installed around the growth chamber 1.

The source gas is introduced from the source gas inlet 9 at the top of the growth chamber 1. This causes a gas phase reaction in the vicinity of the heated wafer 6. Then, a thin film is formed on the wafer 6.

The raw material gas is composed of a gas used directly for forming a thin film and a carrier gas.

The exhaust gas is discharged from the gas outlet 10. A vacuum exhaust device 21 is provided at the tip of the gas outlet 10 to suck gas.

The susceptor 4 is supported by a vertical rotation shaft 20 so as to be rotatable and vertically movable.

During vapor phase growth, the susceptor 4 is above and the gate valve 2 is closed.

When the vapor phase growth is completed, the wafer has to be replaced. If the growth chamber 1 is opened, the inside of the growth chamber 1 will be exposed to the atmosphere, causing pollution, and it will take time to evacuate again.

Therefore, the sample exchange chamber 7 is located below the growth chamber 1 and is connected to the load lock chamber 3 via the gate valve 2.

The load lock chamber 3 can also be evacuated by the vacuum exhaust device 22.

A fork transport device 5 is horizontally provided so that the load lock chamber 3 can enter the sample exchange chamber 7. The fork carrier is called horizontal because it moves laterally.

FIG. 5 shows a perspective view of the fork carrier device 5 according to the conventional example.

This is composed of a support rod 11 which is long in the horizontal direction, a connecting plate 14 fixed to the front end of the supporting rod 11, and a pedestal 12 formed further forward of the connecting plate 14.

A susceptor through hole 13 for passing the susceptor 4 is opened at the center of the pedestal 12. The front of the susceptor through hole 13 is also cut out, but the opening 17 is narrower so that the wafer does not fall. The narrow stopper 15 prevents the wafer from falling forward.

Since the front opening passes through the rotation shaft below the susceptor, the distance between the openings is wider than the diameter of the rotation shaft.

A wafer step portion 16 is formed on the upper surface of the pedestal 12, and the side circumference of the wafer is supported by the wafer step portion 16.

The procedure of wafer exchange will be described.

(I) The load lock chamber is evacuated, and the cradle 12 of the fork carrier is emptied to stand by.

(Ii) The rotating shaft 20 is lowered. Open the gate valve 2.

(Iii) Advance the support rod 11 of the fork carrier. The opening 17 passes through the rotary shaft 20 so that the susceptor through hole and the susceptor are vertically aligned.

(Iv) The rotary shaft is further lowered. The susceptor descends,
The wafer is placed on the pedestal 12. This is the state shown in FIG.

(V) The fork carrier is retracted and returned to the load lock chamber. Close the gate valve 2.

(VI) Open the road lock room. Pedestal for processed wafers
Take out from 12.

The above is the process of taking out the wafer. Next, there is a loading process of placing the unprocessed wafer on the susceptor.

(Vii) Place the unprocessed wafer on the pedestal 12.

Close the road lock room 3. Vacuum here.

(Viii) Open the gate valve 2. The fork carrier device 5 is advanced into the sample exchange chamber 7. It is stopped at the position shown in FIG.

(Ix) Raise the rotary shaft 20. An unprocessed wafer is placed on the susceptor 4. Further, the rotary shaft 20 is further raised so that the susceptor 4 is above the pedestal 12. The pedestal 12 is pulled out from the rotary shaft 20. The fork carrier device 5 is retracted.

(X) The gate valve is closed and the load lock chamber 3 is evacuated.

The wafer can now be loaded.

As described above, in the conventional apparatus, it is necessary to perform the operation twice for taking out the processed wafer and mounting the unprocessed wafer.

The fork carrier must reciprocate twice. The load lock chamber must also be evacuated twice.

This takes too much time and is inefficient.

(C) JP-A-60-186033 JP-A-60-186033 (published on S60.9.21) proposes a wafer transfer device in which a pedestal has two upper and lower stages.

The two-stage pedestals are vertically separated from each other, but are in a vertically overlapping position. That is, they are on the same vertical line. Further, a wafer exchange mechanism is provided on the wall opposite to the fork transfer device so as to be expandable and contractible.

A wafer loading / unloading process will be described.

(I) The lower pedestal is emptied, the untreated wafer is placed on the upper pedestal, and the fork carrier is placed in the sample exchange chamber.

(Ii) Place the lower cradle next to the susceptor so that it is level with the susceptor surface.

(Iii) The wafer transfer mechanism kicks the processed wafer on the susceptor and transfers it to the lower pedestal (FIG. 7).

(Iv) Raise the susceptor slightly and line up so that the upper pedestal and the susceptor are at the same height.

The claw of the wafer transfer mechanism hooks the edge of the unprocessed wafer and drags it laterally. Then, the unprocessed wafer is transferred onto the susceptor (FIG. 8).

With such an apparatus, the wafer can be continuously carried in and out. The fork carrier only reciprocates once. The load lock chamber only needs to be evacuated once. The time required for replacement is also short.

(D) Problems to be solved by the invention Although Japanese Patent Laid-Open No. 60-186033 can shorten the time required for transportation, it has the following drawbacks.

(I) The wafer slides sideways on the susceptor and the pedestal. This is something that should be avoided. Wafers are soft and brittle. When the lower surface is rubbed, a part is broken and powder is generated. This can stain the wafer surface. Further, since the wafer is kicked, the wafer may be damaged.

(Ii) The wafer does not always stop at the exact center of the susceptor. Correct positioning is difficult.

(Iii) In addition to the transfer device, a wafer transfer mechanism having a claw for performing complicated movement is required.

(Iv) Since a circular wafer is pushed laterally, it is difficult to accurately guide it. There is a possibility of slipping sideways and falling on the way. Unreliable operation.

(E) Configuration The fork carrier of the present invention has two upper and lower pedestals, but they are not on the same vertical line. The upper cradle is longer and the lower cradle is shorter.

The position where the wafer is placed tends to be difficult in the vertical direction.
The wafer rest of the upper cradle is more forward and the wafer rest of the lower cradle is more rearward.

Further, a mechanism for exchanging the wafer is not required other than the transfer device. In addition, there is no action of sliding the wafer.

It will be described with reference to the drawings.

FIG. 1 is a perspective view of only the front end portion of the fork carrier device of the present invention. FIG. 2 is a bottom view. FIG. 3 is a cross-sectional view showing the procedure of wafer exchange.

A rigid coupling plate 14 is fixed to the tip of a support rod 11 extending in the horizontal direction. In front of the connecting plate 14, two upper and lower pedestals A and B are provided in two stages. It is different from that shown in FIG. 5 and FIG.

Further, the lengths of the upper and lower pedestals A and B are different. Upper cradle A
Is longer.

The part where the wafer should be placed is the upper and lower pedestals A,
This is because B is different.

The upper pedestals A and B are blind plates up to the middle portion, and the wafer mounting portion X is formed at the tip.

The shape of the wafer mounting portion X is arbitrary. At the center of the wafer mounting portion X, a susceptor through hole 13 through which the susceptor can pass vertically is provided.
Is worn.

The front of the susceptor through hole 13 is also an opening 17, but the opening is narrower. The retainers 15 extending inward from both ends prevent the wafer from falling forward.

The opening 17 between the left and right retainers 15 is wide enough for the rotation axis of the susceptor to pass through.

Further, a wafer step portion 16 into which a wafer is fitted is formed on the periphery of the susceptor through hole 13. When the wafer is tightly fitted into the wafer step portion 16, the wafer does not move left and right and front and back.

As described above, the structure of the wafer mounting portion X is arbitrary and may be the same as that shown in FIG.

Lower cradle B is shorter. It does not overlap the wafer mounting portion X of the upper cradle A. The wafer mounting portion Y is located on the inner side.

The lower wafer mounting portion Y is directly below the blind plate portion of the upper pedestal A. This is clearly shown in the bottom view of FIG.

The lower wafer placing part Y has the same structure. There is a susceptor through hole 13 in the center, and there is a narrower opening 17 in front of it. A wafer step portion 16 is formed on the upper peripheral edge of the susceptor through hole 13.

The wafer mounting parts X and Y have the same structure. The dimensional relationship will be described below.

The diameter of the susceptor is S, the diameter of the susceptor rotating shaft 20 is T, the diameter of the susceptor through hole 13 is U, and the distance between the openings 17 is W.

The condition S <U (1) T <W (2) is required.

There are two upper and lower wafer mounting portions X and Y. The upper wafer mounting portion X is farther from the connecting plate 14 and the support rod 11, and the wafer mounting portions X and Y are not vertically stacked. Things are important.

Further, if the distance between the upper and lower pedestals A and B is H and the total of the height of the susceptor and the thickness of one wafer is K, then H> K (3). This is because the susceptor on which the wafer is placed can enter between the upper and lower pedestals A and B.

Here, the upper pedestal A and the lower pedestal B are illustrated as being rectangular. However, these may be circular or hexagonal. The wafer step portion 16 and the susceptor through hole may have any shape that matches the wafer shape and the susceptor shape. The outer shape doesn't matter.

(F) Action (i) Fork transfer device 5 in the load lock chamber 3 of FIG.
There is. The gate valve 2 is closed. An unprocessed wafer M is placed on the wafer mounting portion X of the upper pedestal A.

Close the load lock chamber and evacuate.

(Ii) In the vapor phase growth chamber 1, the wafer 6 on the susceptor 4 is subjected to the vapor phase growth process. Since there are processed wafers and unprocessed wafers, the processed wafer is set to N for distinction.

The susceptor 4 is lowered so that the wafer N comes to the sample exchange chamber 7.

(Iii) Open the gate valve 2. The fork carrier device 5 is advanced into the sample exchange chamber 7. At this time, the height of the susceptor is set such that the K portion is inserted into the H portion sandwiched between the upper and lower pedestals A and B.

The rotation shaft 20 is moved between the openings 17 of the wafer mounting portion Y of the lower pedestal B.
Go through. The center line of the rotation axis is aligned with the center lines of the wafer step portion 16 and the susceptor through hole 13.

(Iv) The rotating shaft 20 is lowered. This is the state shown in FIG. The processed wafer N is correctly fitted into the wafer step portion 16 of the lower wafer mounting portion Y.

(V) Lower the rotary shaft 20 further. This is the state shown in FIG. 3 (b). The processed wafer N is removed from the upper surface of the susceptor 4.

(Vi) Move the fork carrier back. The wafer mounting portion X of the upper pedestal A is placed directly above the rotary shaft 20. This is the state shown in FIG.

(Vii) Raise the rotating shaft 20. On the susceptor 4, the unprocessed wafer M that has been placed in the upper wafer mounting portion X is placed. Further, the rotary shaft 20 is raised and the fork carrier is retracted. Since the opening 17 of the wafer mounting portion X is wider than the rotary shaft 20, the upper pedestal can be removed.

This is the state shown in FIG.

(Viii) The fork carrier device 5 is retracted into the load lock chamber 3. Close the gate valve 2.

(Ix) Raise the rotary shaft 20 and lift the susceptor 4 and the unprocessed wafer M into the growth chamber 1. A source gas is introduced to cause vapor phase growth on the wafer M.

The above is one operation of wafer exchange.

In this example, the unprocessed wafer M is placed on the upper wafer placing portion X and the processed wafer N is placed on the lower wafer placing portion Y. However, this may be reversed. In this case, the process of FIG. 3 is carried out in the order of d → c → b → a.

(G) Effect (i) The wafer exchange does not become two separate processes such as a carry-out process and a carry-in process. Since there are two upper and lower receiving plates, the wafer can be carried in and out at once by one reciprocating operation.

The need to frequently expose the roadlock chamber to the atmosphere and pull a vacuum is reduced.

(Ii) The time required for replacement is short.

(Iii) Compared to JP-A-60-186033, which has upper and lower receiving plates,
Since there is no process of sliding the wafer, there is no possibility of damaging the wafer. The risk of damage to the wafer is reduced. Since the wafer does not slide, there is little risk of dust generation. In a vapor phase growth apparatus or the like, the generated dust adversely affects the film growth process. However, the application of the present invention reduces the risk.

(Iv) Further, the life of a straight line introduction machine (not shown) that horizontally supports the support rod 11 of the fork carrier device 5 and moves it horizontally while maintaining a vacuum is extended.

(V) The exchange operation is simply to place the wafer loosely from top to bottom, such as placing it on the susceptor or placing it on the wafer step. Therefore, the wafer can be exchanged reliably.

(Vi) Here, the vapor phase growth apparatus is taken as an example, but the present invention is applicable to all apparatuses of the type in which the wafer is placed horizontally and placed on the susceptor.

It can be applied to an etching device, a sputtering device, a vapor deposition device and the like.

[Brief description of drawings]

FIG. 1 is a perspective view of only the tip portion of the fork carrier device of the present invention. FIG. 2 is a bottom view of the same thing. FIG. 3 is a sectional view showing the operation of exchanging a wafer in the fork transfer device of the present invention. (A) shows a state in which the susceptor is passed through the lower wafer mounting portion.
(B) shows a state in which the processed wafer N is placed on the lower wafer placing portion. (C) shows a state in which the susceptor is positioned directly below the unprocessed wafer M in the upper wafer mounting portion. (D) shows a state in which the unprocessed wafer M is placed on the susceptor and the fork transfer device is retracted. FIG. 4 is a schematic configuration diagram of a vertical vapor phase growth apparatus. FIG. 5 is a front perspective view of a single-sheet fork conveying device according to a conventional example. FIG. 6 is a sectional view showing a state where a wafer is placed on the receiving plate of FIG. FIG. 7 is a sectional view showing the operation of transferring a wafer from a susceptor to a cradle according to JP-A-60-186033. FIG. 8 is a sectional view showing the operation of transferring the wafer of JP-A-60-186033 from the pedestal to the susceptor. 1 …… Growth chamber 2 …… Gate valve 3 …… Road lock chamber 4 …… Susceptor 5 …… Fork carrier 6 …… Wafer 7 …… Sample exchange chamber 8 …… High frequency coil 9 …… Raw material gas inlet 10 …… Gas outlet 11 …… Support rod 12 …… Receptor 13 …… Susceptor through hole 14 …… Coupling plate 15 …… Retaining 16 …… Wafer step 17 …… Opening A …… Upper pedestal B …… Lower Cradle X …… Wafer mounting section Y …… Wafer mounting section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 21/306 H05K 5/04 7362-4E

Claims (1)

[Scope of utility model registration request] 1. A wafer 6 is placed on a susceptor 4 fixed on a rotatable shaft 20 which can be raised and lowered, and the wafer 6 is processed in a reaction chamber, and the susceptor 4 is lowered into a sample exchange chamber to remove the wafer. A fork transfer device for transferring a wafer of a device which is designed to be exchanged, and a support rod 11 capable of reciprocating between a sample exchange chamber 7 and a load lock chamber 3 connected via a gate valve 2; It is composed of an upper pedestal A and a lower pedestal B, which are provided at the top and bottom at the top and bottom and have wafer mounting portions X and Y. The wafer mounting portions X and Y are susceptor through holes.
13 and a wafer step portion 16 on which the wafer is to be fitted, and an opening portion 17 through which the susceptor rotation shaft 20 can pass, and the upper and lower wafer mounting portions X and Y are vertically overlapped. The lower pedestal B is located at the wafer mounting portion X of the upper pedestal A.
The double-fork horizontal transfer device is characterized in that it is located farther from the support rod 11 than the wafer mounting part Y of FIG.