JP2000100896A - Method and device for carrying wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily build a construction which is necessary for feeding out a wafer, while adopting a method for carrying a wafer kept in floating state. SOLUTION: A wafer-carrying device A carries a wafer W in floating state by gas G which is jetted out of a number of a discharge holes 1, etc. It is provided with a unit body 10 which has a discharge surface 2, where the discharge holes 1, etc., are formed and can move horizontally while holding the floating wafer W on the discharge surface 2, and a guard member 20 which is built along an outer circumference of the discharge surface 2 of the unit body 10 and encloses the entire outer circumference of the wafer W on the discharge surface 2. Furthermore, it is movable vertically so that a first guard member 20A enclosing almost half around a feeding direction F of the wafer W is pulled down below the discharge surface 2. A jetting direction of gas G jetted out of a first discharge hole 1a of the discharge holes 1, etc., positioned at the side of the feeding direction F is biased in the side of the feeding direction F of the wafer W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type wafer transfer apparatus for transferring a semiconductor wafer (hereinafter simply referred to as "wafer") in a floating state, and a wafer transfer method.

[0002]

2. Description of the Related Art In the formation of semiconductor integrated circuits such as ICs and LSIs, various process processes such as resist coating, exposure, and development are performed. I have. In the wafer transfer process that requires such delivery,
Conventionally, an arm system or a belt conveyor system has been adopted, but since the wafer directly contacts the arm or belt, it causes adhesion of dust and the like, and is transported next by transporting the heated wafer. There is a problem that heat is exerted on the wafer.

In order to solve the above-mentioned drawbacks, recently, a non-contact type wafer transfer device for transferring a wafer in a floating state has been considered. As an outline of this non-contact type wafer transfer device, the gas ejected from a large number of ejection holes is blown vertically to the back surface of the wafer,
It is characterized in that the wafer placed on the discharge surface is conveyed in a predetermined direction while floating slightly upward by the wind pressure generated thereby. As a specific transport means, in order to send the wafer to the target stage, a floating holding part for the wafer is provided on the movable arm, and the floating arm is moved near the target stage by moving the movable arm. After that, there is a method in which another arm is used to grab the wafer from the floating holder and place it on the stage. In addition, while laying a plane line along the transport route,
By forming the large number of discharge holes on the plane line and controlling the flow rate of the gas ejected from each discharge hole sequentially along the transfer direction, the wafer is transferred while floating on the plane line. There are ways. With either method, the wafer floats by the wind pressure in the transfer section and is brought into a state where it does not come into contact with other members, so that the problems such as the attachment of dust and the influence of heat as described above can be effectively prevented. Has been resolved.

[0004]

However, according to the above-mentioned conventional non-contact type wafer transfer device, the adhesion of dust and the like can be reduced by applying technical measures such as floating the wafer by gas ejected from the ejection holes. Even if the problem such as the influence of heat is effectively solved, the mechanism for sending out the wafer has a complicated configuration.

That is, in the above-mentioned arm type wafer transfer device, another arm for grasping the wafer is required, and accordingly, a complicated arm mechanism has to be constructed. on the other hand,
In the above-mentioned flat line type wafer transfer device, it is necessary to individually control the flow rate of gas ejected from each discharge hole formed on the flat line, and it is necessary to construct a complicated control mechanism accordingly.

The present invention has been conceived in view of the above circumstances, and employs a non-contact method of transporting a wafer in a floating state, while providing a mechanism necessary for sending out the wafer. It is an object of the present invention to provide a wafer transfer device and a wafer transfer method that can be easily constructed.

[0007]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, the wafer transfer device provided by the present invention floats the wafer on the discharge surface where these discharge holes are formed while blowing the gas discharged from the many discharge holes against the back surface of the wafer. In a wafer transfer apparatus for transferring a wafer in a state where the discharge is performed, at least one of the discharge holes is deflected in a direction in which a gas ejected from the discharge hole is directed to a wafer sending direction.

Further, according to the wafer transfer method provided by the present invention, a gas ejected from a large number of ejection holes is blown against the back surface of the wafer, and the wafer is floated on the ejection surface formed with these ejection holes. A method of transporting wafers in a state where the wafer is transported in a state where the gas is ejected from at least one of the ejection holes in a direction deflected to the wafer sending direction, and the wafer is ejected from the ejection surface. The method is characterized in that the wafer is conveyed along the feed direction in a state of being floated on the discharge surface by the laminar flow generated in the narrow gap.

That is, the above-described wafer transfer device and the wafer transfer method employ substantially the same technical means, and in the present invention in which such technical means are employed, the wafer is disposed on the discharge surface. Are arranged, and the gas ejected from the large number of ejection holes blows against the back surface of the wafer. Then, the wafer on the discharge surface floats with a narrow gap slightly above the discharge surface due to the wind pressure acting perpendicular to the wafer surface.
On the other hand, in the narrow gap between the wafer and the discharge surface, a laminar flow of a flow toward the feed direction parallel to the wafer surface is generated due to the ejection of the gas whose injection direction is deflected toward the feed direction of the wafer. Due to the laminar flow, a transfer force acts on the back surface of the wafer in the feed direction, and the wafer floating on the discharge surface receives the transfer force due to the laminar flow and moves horizontally along the transfer direction. Will move. That is, the wafer on the discharge surface exhibits a fluid behavior along the feed direction while floating on the surface.

Therefore, according to the wafer transfer apparatus and the wafer transfer method provided by the present invention, a non-contact method is adopted in which the wafer is transferred while being floated on the discharge surface, so that dust or the like adheres. Problems such as heat and heat are effectively solved. In addition, as a configuration necessary for non-contact transfer, when gas is blown out from a large number of discharge holes against the back surface of the wafer,
It is only necessary to deflect the gas injection direction for some or all of the discharge holes to the wafer feed direction, so that the wafer can be transported in a floating state, and it is necessary to send the wafer A simple mechanism can be easily constructed simply by ejecting gas from the discharge holes.

The number of ejection holes whose gas injection direction is deflected toward the feed direction needs an appropriate number according to the total number of ejection holes, but generally a large number are formed. It is desirable.

In a preferred embodiment, the apparatus has a discharge surface in which a large number of the discharge holes are formed in a manner similar to the shape of the wafer in plan view, and holds the wafer in a floating state on the discharge surface. While the unit itself is movable, the unit body is assembled in an annular wall shape along the outer periphery of the ejection surface of the unit body, and surrounds the entire outer periphery of the wafer floating on the ejection surface, at least. A structure including a guard member which is vertically movable so that a portion surrounding substantially the half circumference of the wafer changes from a state facing the feed direction side of the wafer to a state pulled down below the discharge surface. It can be.

According to such a configuration, the wafer is in a state in which the entire length of the outer periphery is surrounded by the guard member on the discharge surface of the unit main body, and is stably held stationary in a state of being floated by the gas ejected from the ejection holes. Is done. And
When the unit body itself moves, the wafer is carried to the destination, and when the unit body stops at the destination, a part of the guard member facing the feed direction of the wafer is lower than the discharge surface of the unit body. To be reduced to At this time, the unit body is placed sideways close to a stage or the like on which a wafer is placed.
Then, the wafer on the discharge surface is sent out to the side of the unit main body on the laminar flow flowing in the feed direction side, and the wafer moves fluidly to a stage or the like laid laterally on the unit main body. The transfer of the wafer is completed. Therefore, when transporting the wafer, the unit body itself is moved to the destination while holding the wafer floating above the discharge surface of the unit body, and the guard facing the feed direction side at the destination point is used. Since the wafer can be sent out of the unit body only by pulling a part of the member below the discharge surface, there is no need for special external means for taking out the wafer from the unit body. Can be easily delivered.

In another preferred embodiment, among the plurality of ejection holes, the ejection hole whose gas ejection direction is deflected to the wafer sending direction side is provided on the ejection surface of the unit main body. A configuration provided at a portion close to the direction side can be adopted.

According to such a configuration, the discharge hole for gas ejection which generates a laminar flow in the narrow gap between the wafer and the discharge surface is provided at a position on the discharge surface close to the wafer feeding direction. Therefore, when the wafer is sent out from the discharge surface of the unit body, the laminar flow flows in the feed direction side on the lower surface of the wafer without weakening, and a sufficient transfer force to send out the wafer acts on the wafer. The wafer can be sent out such that it is quickly moved horizontally from the discharge surface.

Further, as another preferred embodiment,
The guard member may be provided with a blowout hole for horizontally blowing out a gas toward the outer periphery of the wafer floating on the discharge surface of the unit body.

According to such a configuration, the wafer held stationary in a state of floating above the discharge surface of the unit body is surrounded by the guard member. Since it is devised not to come into contact with each other by gas ejected horizontally from the blowing hole provided in the guard member, it is possible to reduce the impact on the wafer due to contact with the guard member, The wafer can be held stationary at a fixed position on the ejection surface as much as possible.

Further, as another preferred embodiment, the gas ejected from the ejection hole or the ejection hole may be an inert gas having low reactivity with the wafer.

According to this structure, the gas blown to the wafer is an inert gas having low reactivity with the wafer, so that the wafer surface is not contaminated by the gas and the atmosphere is clean. The wafer can be transferred under the environment.

The inert gas is preferably a so-called clean dry air such as a nitrogen gas whose impurity concentration has been reduced to a predetermined level.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing an embodiment of the wafer transfer device according to the present invention, FIG. 2 is a cross-sectional view showing the wafer transfer device shown in FIG. ,
It is the top view which showed the wafer conveyance apparatus from the upper surface.

The wafer transfer device A shown in FIGS. 1 to 3
Transports the wafer W in a state where the wafer W is floated on the discharge surface 2 on which the discharge holes 1 are formed, while the gas G discharged from the large number of discharge holes 1 is blown against the back surface WB of the wafer W. That is, a non-contact type transfer method is partially adopted using a so-called air flow transfer. The wafer transfer apparatus A has a discharge surface 2 in which a large number of discharge holes 1 are formed, and a unit main body 10 in which the entire unit can be moved horizontally, and an outer periphery of the discharge surface 2 of the unit main body 10. A portion 20A surrounding the entire outer circumference of the wafer W, which is assembled in a ring wall shape and floated on the discharge surface 10, has a portion 20A surrounding substantially a half circumference of the wafer W in a feed direction F of the wafer W.
A guard member 20 that can move up and down so as to change from a state facing the side to a state pulled down below the discharge surface 2 is schematically configured.

The unit body 10 is configured to be movable on a flat plane line by a drive mechanism (not shown), and has a discharge surface 2 slightly larger than the disk shape of the wafer W. Wafer W on discharge surface 2
Is arranged. A large number of discharge holes 1 for discharging gas G are provided over the entire discharge surface 2. Gas G
As the inert gas, an inert gas having a low reactivity with the wafer W, for example, a nitrogen gas whose impurity concentration is reduced to a predetermined level is used. Out of the large number of discharge holes 1, a predetermined number of first discharge holes 1 a provided in a portion near the wafer W in the feed direction F are, as shown well in FIG. The ejection direction G1 is deflected to the feed direction F side. On the other hand, the other second discharge holes 1
b, the gas G injection direction G2 is substantially perpendicular to the discharge surface 2. These first and second discharge holes 1a,
The gas G is guided to 1b from outside the unit main body 10 via tunnel-like gas inflow paths 1aa and 1ba provided in the unit main body 10, respectively. That is, the gas G1, G ejected from the first and second discharge holes 1a, 1b
In some cases, wind pressure acts on the back surface WB of the wafer W perpendicularly, and the wafer W floats with a narrow gap between it and the ejection surface 2. Here, depending on the gas G1 ejected from the second ejection holes 1a, a laminar flow is generated parallel to the ejection surface 2 toward the feed direction F. Since the transport force acts on the back surface WB of the wafer W toward the feed direction F by the laminar flow, the wafer W moves in the feed direction F while floating on the discharge surface 2. Become.

The guard member 20 includes a first guard member 20A movable up and down with respect to the discharge surface 2 and a second guard member 20B fixed to the discharge surface 2. It is configured. The first guard member 20A is provided along substantially half the circumference in the feed direction F of the wafer W, which is the outer peripheral portion of the ejection surface 2, and can be opened and closed by moving up and down by a drive mechanism (not shown). On the other hand, the second guard member 20B is located symmetrically with respect to the first guard member 20A, and is provided along substantially half the circumference opposite to the feed direction F of the wafer W, which is the outer peripheral portion of the ejection surface 2. . In other words, in a state where the first guard member 20A is raised on the discharge surface 2, the first and second guard members 20A, 20A
The state where the wafer W on the ejection surface 2 is surrounded by the entire outer periphery by OB. On the other hand, the first guard member 20A
Is pulled down below the discharge surface 2, the wafer W on the discharge surface 2 moves from the portion closed by the first guard member 20 </ b> A along the feed direction F to the unit body 1.
It is possible to advance outside zero. The first and second guard members 20A and 20B are attached to the discharge surface 2 of the unit body 10.
A large number of blowing holes 20a are provided for horizontally blowing out the gas G toward the outer periphery of the wafer W floating above. Also in these blowout holes 20a, nitrogen gas or the like is guided from outside the unit body 10 and can be blown out similarly to the discharge holes 1.

In the above configuration, a gas supply mechanism such as a pump for supplying the gas G to the gas inflow paths 1aa, 1ba and the outlet 20a is omitted from the drawings. The same components as those described above are used, and may be provided inside or outside the unit main body 10.

Next, a method of transferring the wafer W using the wafer transfer apparatus A will be briefly described with reference to FIGS.

First, as shown in FIG.
The wafer W that has been subjected to the process processing such as exposure and development is placed on the ejection surface 2 of the unit main body 10 by an arm mechanism or the like (not shown) in order to be transferred to the next process processing. At this time, from each of the discharge holes 1 on the discharge surface 2 and the blowout hole 20a of the guard member 20,
Gas G is ejected toward a predetermined ejection direction. That is, the gas G ejected from the large number of ejection holes 1 blows against the back surface WB of the wafer W. Then, the wafer W on the discharge surface 2 floats slightly above the discharge surface 2 by a wind pressure acting perpendicular to the rear surface WB with a small gap. The wafer W floating above the discharge surface 2 is surrounded by the guard member 20, and the guard member 20 and the outer periphery of the wafer W are connected to the blowing holes provided in the guard member 20. The gas G ejected horizontally from 20a does not come into contact with each other. Thereby, the wafer W is
The unit main body 10 that is held stationary in a state of floating near the center on the ejection surface 2 as much as possible, and horizontally holds the wafer W, which is to be described later, is provided at a location where the next process is performed. Move.

FIG. 4 is a cross-sectional view for explaining a state in which the wafer W is sent out to the target stage S using the wafer transfer device A. As shown in FIG. The unit body 10 holding W is
It is laid sideways in the state of being close to the target stage S while moving horizontally. At this time, the height of the surface of the stage S and the height of the ejection surface 2 are almost equal.

Thereafter, the first guard member 20A is pulled down below the discharge surface 2. At this time, if the gas G is not ejected from the first ejection hole 1a, the gas G is supplied through the gas inflow path 1aa following the first ejection hole 1a and ejected from the first ejection hole 1a. When the required transfer force cannot be obtained for the wafer W even by the gas G, the supply amount of the gas G is increased through the gas inflow path 1aa.

Then, in the narrow gap between the wafer W and the discharge surface 2, the gas G ejected from the first ejection hole 1 a whose ejection direction is deflected toward the feed direction F of the wafer W causes the back surface of the wafer W to be exposed. A laminar flow L of a flow toward the feed direction F occurs in parallel with WB. This laminar flow L causes the wafer W
, A transfer force acts in the feed direction F, and the wafer W floating on the discharge surface 2 receives the transfer force due to the laminar flow L to move horizontally along the feed direction F. Will move.

At this time, the first guard member 20A facing the wafer W in the feed direction F is pulled down below the ejection surface 2, so that the wafer W
Is floated from the discharge surface 2 onto the target surface of the stage S in a fluid state, and the wind pressure finally received is weakened and stopped in contact with the surface of the stage S.

That is, in the case of this wafer transfer method, in the transfer section where the wafer W is transferred to the next process, the wafer W is floated on the discharge surface 2 by the wind pressure to be in a non-contact state. When the wafer W is sent out to the target stage S in the next process, a method is used in which the wafer W is sent out in a non-contact state by an air current transfer method.

Therefore, according to the wafer transfer apparatus A having the above-described configuration and operation, not only when the wafer W is sent out from the transfer section to the target stage S, but also in the transfer section,
A non-contact method by airflow, in which the wafer W is sent out while being floated on the ejection surface 2, is adopted.
Problems such as adhesion of dust and the influence of heat are effectively solved. Moreover, in order to transport the wafer W by the air flow transport method, when the gas G is blown out from a large number of the discharge holes 1 to the back surface WB of the wafer W and blown against the back surface WB, some of the discharge holes ( For the first discharge port 1a), the gas G
It is only necessary to deflect the jetting direction of the wafer W toward the feed direction F of the wafer W, and the wafer W can be sent to the target stage S or the like in a floating state while the wafer W is floating. A mechanism necessary for sending out W can be easily constructed as a configuration for only ejecting the gas G from the discharge holes 1.

When transporting the wafer W, the unit body 10 itself is moved to the vicinity of the target stage S while holding the wafer W floating above the discharge surface 2 of the unit body 10. The wafer W can be sent out of the unit main body 10 only by pulling the first guard member 20A facing the feed direction F side below the discharge surface 2 near the stage S, so that the wafer W is taken out from the unit main body 10. No special external means is required, and the wafer W can be easily transferred between the unit body 10 and the stage S.

In the above-described embodiment, when the processed wafer W is arranged on the ejection surface 2 of the unit body 10, the wafer mechanism is described as being arranged on the ejection surface 2 by the arm mechanism. As shown in FIG. 4, a method of sending the wafer W onto the discharge surface 2 by an air current transfer method may be applied as in the case of sending the wafer W from the discharge surface 2 onto the stage S. In this case, similarly to the first guard member 20A, the second guard member 20B
Is configured to be able to move up and down so as to be pulled down below the discharge surface 2, and a discharge hole having a cross-sectional structure similar to that of the first discharge hole 1 a is provided on a stage or the like on the side for sending the wafer W to the discharge surface 2. It may be provided.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a wafer transfer device according to the present invention.

FIG. 2 is a cross-sectional view showing a cross section XX of the wafer transfer device shown in FIG.

FIG. 3 is a plan view showing the wafer transfer device from above.

FIG. 4 is a cross-sectional view shown for explaining a state in which a wafer is sent to a target stage using a wafer transfer device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 discharge hole 1a first discharge hole 1b second discharge hole 2 discharge surface 10 unit body 20 guard member 20A first guard member 20B second guard member 20a blowout hole A wafer transfer device F sending direction G gas L layer Flow S Stage W Wafer

Claims (6)

[Claims] 1. A wafer transfer device for blowing a gas ejected from a large number of discharge holes onto a back surface of a wafer, and transferring the wafer in a state of floating above the discharge surface having the discharge holes. A wafer transfer device, wherein at least one of the discharge holes is deflected in a jetting direction of a gas spouted from the jetting hole toward a wafer feeding direction. 2. A unit having a discharge surface in which a large number of the discharge holes are formed in a manner similar to the shape of the wafer in plan view, and while holding the wafer in a floating state on the discharge surface, the unit itself is formed. A movable unit main body, which is assembled in an annular wall shape along the outer periphery of the discharge surface of the unit main body and surrounds the entire outer peripheral length of the wafer floating on the discharge surface, while at least substantially half the circumference of the wafer And a guard member movable up and down so as to change from a state facing the feed direction side of the wafer to a state pulled down below the ejection surface. A wafer transfer device as described in the above. 3. The discharge hole, of the plurality of discharge holes, in which the gas injection direction is deflected to the wafer feed direction side, is provided at a position near the wafer feed direction side on the discharge surface of the unit body. The wafer transfer device according to claim 2, wherein: 4. The guard member is provided with a blowing hole for horizontally blowing a gas toward an outer periphery of the wafer floating on a discharge surface of the unit body. 3. The wafer transfer device according to claim 1. 5. The wafer transfer device according to claim 1, wherein the gas ejected from the discharge hole or the blowout hole is an inert gas having low reactivity with the wafer. 6. A wafer transfer method wherein a gas ejected from a large number of discharge holes is blown against the back surface of a wafer, and the wafer is transferred in a state of being floated on the discharge surface on which the discharge holes are formed. The gas ejected from at least one of the ejection holes is ejected in a direction deflected to the direction of feed of the wafer, and the ejection is caused by a laminar flow generated in a narrow gap between the wafer and the ejection surface. A wafer transfer method, wherein the wafer is transferred along a feed direction while being floated on a surface.