JP4893481B2 - Silicon wafer transfer device - Google Patents

Description

  The present invention relates to a silicon wafer transfer apparatus for transferring a silicon wafer without bringing it into contact, and more particularly to a silicon wafer transfer apparatus for transferring the wafer in a non-contact manner with other members in the state of floating the wafer. .

  Conventionally, in a silicon wafer manufacturing apparatus, when a wafer cut from a semiconductor single crystal is transported, a direct handling method using a robot hand or a transport method using a belt has been used. In general, the semiconductor manufacturing apparatus is transported between apparatuses by a human moving the wafer in a dedicated box.

  However, in the above transport method, there is a problem that the surface of the silicon wafer is scratched by contact with the robot hand, and this scratch causes a defect. Further, when the wafer is transported, there are problems such as adhesion of metal impurities and particles and generation of a natural oxide film. At the present time when semiconductor devices are highly integrated and miniaturized, the occurrence of defects and the attachment of foreign substances cause deterioration of the performance of the device, so it is necessary to eliminate them as much as possible.

  Therefore, as a silicon wafer transfer device that solves the above-described problems, for example, an air current transfer device that floats and transfers the wafer as shown in Patent Document 1 can be cited. A nozzle for jetting the gas, a passage for the plate-like object, a conveyance path in which the nozzle is installed, a valve for adjusting the amount of gas supplied to the nozzle, and the position and moving speed of the plate-like object And a plate-like object detecting means for detecting the above, and a silicon wafer is floated by jetting gas from the nozzle while adjusting with a valve, and is conveyed in a non-contact state with a robot hand or the like.

  Further, as another silicon wafer transfer device, for example, a transfer device that stores and transfers a silicon wafer in a predetermined transfer chamber as shown in Patent Document 2 can be cited. The wafer transfer apparatus is capable of transferring while maintaining a high vacuum state with a small amount of gas introduced by moving the transfer chamber to a target position with the wafer floating in the transfer chamber. .

However, in the silicon wafer transfer device disclosed in Patent Document 1, in order to eject gas from the nozzle only at the position where the wafer exists, a high technique is required for controlling the sensor and the nozzle, and therefore the wafer is transferred stably. There was a problem that was difficult. Further, in the wafer transfer apparatus of Patent Document 2, the wafer is not sufficiently fixed in the transfer chamber, so that the side edge portion of the wafer may collide with the side wall in the transfer chamber.
JP 7-228342 A JP 2001-176950 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a silicon wafer transfer device that can stably transfer a silicon wafer without contact with other members without contact with impurities.

  As a result of repeated studies to solve the above problems, the present inventor has at least one linear groove provided in parallel with the plurality of holes and the transport direction in the space in which the silicon wafer transport device transports the wafer. A transfer table having holes, wafer levitation means for jetting gas from the holes to the back surface of the wafer, and at least one first nozzle in each linear groove, the first nozzle being The straight groove hole is moved in the transfer direction while jetting a gas having a pressure higher than that of the gas ejected from the hole of the wafer levitation means from a position in front of the transfer direction with respect to the straight groove hole portion where the wafer is located. By providing a moving wafer transfer means and a detection means located above the transfer table for detecting the position of the wafer, a silicon wafer can be formed in the same manner as in a conventional transfer apparatus. It is possible to suppress the adhesion of impurities by transporting it in a non-contact state, and by pressing and transporting the side edge of the wafer in a floating state with a high-pressure gas ejected from the first nozzle of the wafer transport means The present inventors have found that there is no difficulty in controlling the sensors and nozzles as described above and the wafer can be stably conveyed.

In order to achieve the above object, the gist of the present invention is as follows.
(1) In a space for transferring a silicon wafer, a transfer table having a plurality of holes and at least one linear groove provided in parallel with the transfer direction, and gas is jetted from the holes to the back surface of the wafer Wafer levitation means for levitating the wafer, and at least one first nozzle in each linear groove, the first nozzle being in the transport direction more than the portion of the linear groove where the wafer before transport is located From the near side position, the side groove of the wafer in a floating state is pressed by moving the linear groove hole in the transport direction while jetting a gas having a pressure higher than the gas jetted from the hole of the wafer floating means. A silicon wafer transfer apparatus, comprising: a wafer transfer means for transferring the wafer; and a detection means positioned above the transfer table for detecting the position of the wafer.

(2) The silicon wafer transfer device according to (1), wherein the silicon wafer transfer device further includes a foreign matter adsorbing unit that absorbs foreign matter in the transfer space by generating static electricity.

(3) The silicon wafer transfer device has at least one second nozzle that jets gas to a side edge portion on the back side in the transfer direction of the wafer in the linear groove, and the second nozzle (1) or (1), further comprising wafer stopping means for stopping the wafer when the transferred wafer is at a transfer completion position by ejecting a gas having a pressure higher than that of the wafer floating means. 2) The silicon wafer transfer device according to 2).

(4) The second nozzle is configured to be movable in the linear groove hole, and the first and second nozzles are arranged to sandwich the wafer, and the first and second nozzles and the arrangement of the wafer are arranged. The silicon wafer transfer apparatus according to (3), wherein the wafer is stably transferred by moving the first and second nozzles while maintaining the relationship.

(5) The silicon wafer transfer device further includes a circular groove hole at a predetermined position of the transfer table, and has at least one third nozzle in the circular groove hole, and the third nozzle floats the wafer. (1) to (1), further comprising wafer rotating means for rotating the wafer by moving the circular groove hole while ejecting a gas having a pressure higher than that of the gas ejected from the hole of the means. 4) The silicon wafer transfer device according to any one of 4).

  According to the present invention, it is possible to provide a silicon wafer transfer apparatus that can stably transfer without contacting impurities with other members without attaching impurities to the silicon wafer.

A silicon wafer transfer device according to the present invention will be described with reference to the drawings.
FIG. 1 is a view of the interior of a space for transporting a silicon wafer by removing the top of the silicon wafer transport apparatus according to the present invention, and FIG. 2 is a view of the interior of the space for transporting the silicon wafer as viewed from the side. FIG.

  A silicon wafer transfer apparatus 1 according to the present invention mainly includes a transfer table 4, a wafer floating means 5, a wafer transfer means 6, and a detection means 7 in a space 3 for transferring a silicon wafer 2.

(Transport table)
As shown in FIG. 1, the silicon wafer transfer apparatus 1 according to the present invention includes the transfer table 4 having a plurality of holes 41 and at least one linear groove hole 42 provided in parallel with the transfer direction. As a constituent member of the transfer table 4, for example, a member obtained by coating SiC with ceramics, resin, or metal is preferable in terms of avoiding metal contamination from the structural member. Furthermore, it is preferable that the width W4 of the transfer table 4 has such a width that even a silicon wafer having a large area can be transferred, and the length L4 is a length according to the application.

  The hole 41 may be circular or elliptical, and is preferably provided at periodic intervals as shown in FIG. 1, but the wafer can be floated. There is no particular limitation as long as it is provided at a certain interval. In addition, at least one (two in FIG. 1) linear groove 42 is provided in parallel with the traveling direction of the wafer 2 on the transfer table 4, and the width W42 of the groove 42 is a first described later. It is determined by the size of the nozzle 61 and the like.

(Wafer floating means)
Further, as shown in FIG. 1, the silicon wafer transfer apparatus 1 according to the present invention has a wafer floating means 5 that jets a gas 50 from the hole 41 to the back surface of the wafer 2 to float the wafer 2. As shown in FIG. 2, the wafer levitation means 5 according to the present invention is not particularly limited as long as it is configured to be able to jet a gas 50 to the back surface of the wafer and float it. The wafer levitation means 5 controls, for example, a gas ejection port 51 for ejecting the gas 50, a valve 52 for adjusting the supply amount of the gas 50, a gas supply pipe 53 that is a gas passageway, and the movement of the valve 52. The gas flow controller 54 for storing the gas 50 and a gas tank (not shown) storing the gas 50 can be used. With this configuration, since the wafer can be kept in a floating state, the back surface of the wafer is not in direct contact with other members such as the transfer table 4 during transfer, and flaws and impurities are adhered during contact. Can be suppressed.

  The type of the gas 50 to be ejected is not particularly limited as long as it does not include impurities such as foreign matters, but argon gas, nitrogen gas, or the like can be used, and the temperature is the same level as the transport atmosphere. However, it is preferable in that the temperature drop due to gas introduction can be prevented and the atmospheric temperature can be maintained. Furthermore, it is preferable that the pressure of the gas is a pressure sufficient to float the wafer to be transferred.

(Wafer transfer means)
Furthermore, the silicon wafer transfer apparatus 1 according to the present invention has at least one first nozzle 61 in each linear groove 42 as shown in FIG. 1, and the first nozzle 61 as shown in FIG. 61, while the gas 60 having a pressure higher than that of the gas 50 ejected from the hole of the wafer levitation means is ejected from the position in the front side of the transport direction with respect to the portion of the linear groove where the wafer 2 before transport is located. The wafer conveyance means 6 which conveys by pressing the side edge 2a of the wafer 2 in the floating state by moving the groove in the conveyance direction. If this wafer transfer means 6 is used, the gas 60 having a high pressure presses the side edge portion 2a of the wafer 2, so that the force that directs the wafer 2 in the transfer direction as compared with the transfer method using the conventional gas. As a result, the wafer 2 can be transported stably. As a result, it is possible to suppress the generation of scratches and the adhesion of impurities in the silicon wafer at the time of contact.

  Here, the wafer transfer means 6 has at least one first nozzle 61 in the linear groove hole 42, and moves the linear groove hole in the transfer direction while jetting high pressure gas 60. For example, the first nozzle 61, a moving mechanism (not shown) for moving the first nozzle, and a valve (not shown) for adjusting the supply amount of the gas 60 may be used. ), A gas supply pipe (not shown) as a passage for the gas 60, a mass flow controller 54 for controlling the movement of the valve 52, and a gas tank (not shown) storing the gas 60 Can be configured.

  The first nozzle 61 normally ejects upward, but has an angle adjustment function, and if the angle can be adjusted as necessary, the silicon wafer 2 can be conveyed more stably. This is preferable. Furthermore, the pressure of the gas 60 ejected from the first nozzle 61 needs to be higher than that of the gas 50 ejected from the hole 41, and can be changed depending on the conditions for transporting the wafer 2, but the gas ejected from the hole It is more preferable that the pressure be several percent higher than the pressure of the gas 50 to be used.

(Detection means)
Furthermore, as shown in FIG. 2, the silicon wafer transfer apparatus 1 according to the present invention is positioned above the transfer table 4 and detects the position in the height direction and the width direction of the wafer 2. Means 7 are provided. When the detecting means 7 detects the position of the wafer 2 with high accuracy, the flying height of the wafer 2 is kept constant by adjusting the valve 52 and the position of the first nozzle is accurately controlled. be able to.

  The detection means 7 needs to have a configuration capable of detecting the position of the wafer 2. For example, the infrared sensor 71 preferably includes an infrared light emitting unit and an infrared light receiving unit. This is because the position of the silicon wafer 2 can be accurately detected by using the infrared sensor 71 as a position sensor for the wafer 2.

(Foreign matter adsorption means)
The silicon wafer transfer apparatus 1 according to the present invention preferably further includes a foreign matter adsorbing means 8 for adsorbing foreign matters in the transfer space 3 by generating static electricity. As shown in FIG. 2, by providing the foreign matter adsorbing means 8 on the lateral wall and the upper and lower portions, foreign matter such as particles generated in the transfer space 3 is adsorbed, and further, a gas 50 ejected from the round hole 41. This is because the foreign matter contained therein can also be adsorbed, thereby further suppressing the adsorption of impurities to the silicon wafer.

  Further, the foreign matter adsorbing means 8 preferably includes an electrode needle (not shown), a ground electrode (not shown), and a foreign matter adsorbing portion 81 using a corona discharge method. This is because by having this configuration, it is possible to effectively adsorb foreign substances such as particles.

(Wafer stop means)
Furthermore, as shown in FIG. 1, the silicon wafer transfer apparatus 1 according to the present invention has at least one second gas jetting gas into the linear groove hole 42 at the side edge on the back side in the wafer transfer direction. Wafer stop means that has a nozzle 91 and stops the wafer 2 when the transferred wafer 2 is at the transfer completion position by ejecting a gas having a pressure higher than that of the wafer floating means 5 by the second nozzle 91. 9 is preferably provided. Since the gas is ejected from the second nozzle 91 at the same pressure as the first nozzle 61, when the wafer 2 reaches the position to be stopped, a high-pressure gas is applied to the wafer side edge 2a. This is because the wafer 2 can be surely stopped as a result of being able to serve as a stopper by ejecting and pressing.

  Moreover, FIG. 3 is the figure which looked at the inside of the space which removes the top part of the silicon wafer conveyance apparatus which is another one form of this invention, and conveys a silicon wafer from the upper direction. As shown in FIG. 3, the second nozzle 91 is configured to be movable in the linear groove 42, and the first nozzle 61 and the second nozzle 91 are disposed so as to sandwich the wafer 2. If the first nozzle 61 and the second nozzle 91 are moved while maintaining the positional relationship between the first nozzle 61 and the second nozzle 91 and the wafer 2, the wafer 2 is sandwiched between high-pressure gases. This is preferable in that the wafer 2 can be stably conveyed while being fixed between high-pressure gases.

  Further, as shown in FIGS. 1 to 3, if the high pressure gas is ejected so as to surround the transfer table 4 separately from the stop means 9, the wafer 2 is transferred off the transfer route. Even when approaching a side wall (not shown) of the apparatus, it is preferable in that the jet of the high-pressure gas becomes an air wall and the wafer can be prevented from colliding with the side wall.

(Wafer rotation means)
4 and 5 are views of the inside of a space for transferring a silicon wafer by removing the top of a silicon wafer transfer apparatus according to another embodiment of the present invention, and FIG. 4 is a view with the silicon wafer removed. FIG. 5 is a view for conveying a silicon wafer. The silicon wafer transfer apparatus 1 according to the present invention is an apparatus that analyzes in a vacuum like a scanning electron microscope. When a wafer position is specified and fixed in air (referred to as alignment), a wafer is inserted into the apparatus. Since it may be necessary to rotate the transferred silicon wafer 2, as shown in FIG. 4, it further has a circular groove 43 at a predetermined position of the transfer table 4, and the circular groove hole 43 has at least one third nozzle 101, and the third nozzle 101 ejects a gas having a pressure higher than that of the gas 50 ejected from the round hole 41 of the wafer levitation means 5, while forming the circular groove 43. It is preferable to provide wafer rotating means 10 for rotating the wafer 2 by moving. This is because the wafer 2 can be rotated more reliably by providing the wafer rotating means 10.

  Further, as shown in FIG. 5, it is more preferable that the third nozzle 101 is provided at a position corresponding to the notch portion 2b of the wafer 2 to be rotated. This is because if the third nozzle 101 is provided at a position corresponding to the notch portion 2b, the ejected gas can be rotated while cooperating with the notch portion 2b, so that efficient rotation is possible.

(Conveying space)
In addition, the conveyance space 3 of the silicon wafer conveyance apparatus 1 by this invention should just have a space of a predetermined | prescribed magnitude | size. Further, it is preferable that the surface is covered with six walls from the viewpoint of preventing foreign matter from adhering to the wafer. Furthermore, it is more preferable that the upper and lower walls are provided with a hepa filter so that the conveyance space can be kept clean.

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

Example 1
Example 1 includes a transfer table having a plurality of round holes and two straight groove holes provided in parallel with the transfer direction in a space for transferring a silicon wafer having a size of 300 mm as shown in FIG. Wafer levitation means for ejecting gas from the hole to the back surface of the wafer to levitate the wafer, and one first nozzle in each linear groove hole. The first nozzle is located at the position of the wafer before transfer. The straight groove hole is moved in the transfer direction while jetting a gas having a pressure 8% higher than the gas jetted from the round hole of the wafer levitation means from a position on the near side of the transfer direction with respect to the portion of the straight groove hole. A wafer transfer unit that presses and conveys the side edge of the floating wafer; a detection unit that is positioned above the transfer table and detects the position of the wafer; In A silicon wafer transfer device having a foreign matter adsorbing means that is positioned and adsorbs foreign matter in the transfer space by generating static electricity has been prototyped. Thereafter, the silicon wafer was continuously stored in the silicon wafer transfer apparatus for 10 hours, and then the silicon wafer was taken out.

(Example 2)
In Example 2, a silicon wafer transfer device having the same configuration as that of Example 1 except that the foreign matter adsorbing means is not provided is prototyped. As in Example 1, a silicon wafer is placed in the silicon wafer transfer device for 10 hours. The storage was continued, and then the silicon wafer was taken out.

Comparative example

(Comparative Example 1)
Comparative Example 1 is an air current conveying device that floats a plate-like object such as a semiconductor wafer by a gas fluid force and conveys the plate-like object in a non-contact state as described in Patent Document 1, A nozzle for jetting the gas, a passage for the plate-like object, a conveyance path in which the nozzle is installed, a valve for adjusting the amount of gas supplied to the nozzle, and the position and moving speed of the plate-like object The nozzle is installed in a vertical direction or an oblique direction with respect to the transport path, and the valve is provided in a one-to-one correspondence with the nozzle. An air flow conveying device was manufactured. Thereafter, as in Example 1, a silicon wafer having a size of 300 mm was continuously stored in the silicon wafer transfer apparatus for 10 hours, and then the silicon wafer was taken out.

(Evaluation methods)
The number of particles on the silicon wafer surface of Examples 1 and 2 and Comparative Example 1 above Measurements were made using a particle counter and the results were compared.

  From the results in Table 1, it was found that the silicon wafer obtained from Example 1 and Example 2 had fewer particles than the silicon wafer obtained from Comparative Example 1. Therefore, it was found that the silicon wafer transfer device of Example 1 and Example 2 can suppress the adhesion of impurities and can stably transfer compared to the silicon wafer transfer device of Comparative Example 1.

  According to the present invention, it is possible to provide a silicon wafer transfer apparatus that can stably transfer without contacting impurities with other members without attaching impurities to the silicon wafer.

It is the top view which removed the top part and looked at the inside of the space which conveys a silicon wafer about the embodiment of the silicon wafer conveyance device according to the present invention from the upper part. It is the figure which removed the side wall and looked at the inside of the space which conveys the said silicon wafer of the silicon wafer conveyance apparatus of FIG. 1 from the side. 1 is a plan view of the inside of a space for transporting a silicon wafer as viewed from above with the top removed, showing a case where the silicon wafer is at a transport completion position, according to an embodiment of the silicon wafer transport device according to the present invention. 1 is a plan view of an embodiment of a silicon wafer transfer device according to the present invention, in which a space inside a silicon wafer is transferred, viewed from above with the top removed, showing a state in which no silicon wafer exists. It is the top view which removed the top part and was seen from the upper part inside the space which conveys a silicon wafer about another embodiment of the silicon wafer conveyance apparatus according to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon wafer transfer apparatus 2 Silicon wafer 2a Silicon wafer side edge part 2b Silicon wafer notch part 3 Transfer space 4 Transfer table 41 Round hole 42 Straight groove hole 43 Circular groove hole 5 Wafer floating means 51 Jet outlet 52 Valve 53 Supply piping 54 Mass flow controller 6 Wafer transfer means 60 High pressure gas 61 First nozzle 7 Detection means 71 Infrared sensor 8 Dust adsorption means 81 Dust adsorption portion 9 Wafer stop means 91 Second nozzle 10 Wafer rotation means 101 Third nozzle

Claims (5)

  In a space for transferring a silicon wafer, a transfer table having a plurality of holes and at least one linear groove provided in parallel with the transfer direction, and a gas is jetted from the holes to the back surface of the wafer to float the wafer A wafer levitation means to be used, and at least one first nozzle in each linear groove, and the first nozzle is positioned at a position closer to the front side in the transport direction than a portion of the linear groove where the wafer before transport is located. From the above, by moving the linear groove hole in the transport direction while ejecting a gas having a pressure higher than that of the gas ejected from the hole of the wafer levitation means, the side edge portion of the wafer in the floated state is pressed and transported. A silicon wafer transfer apparatus comprising: a wafer transfer means for detecting; and a detection means positioned above the transfer table for detecting the position of the wafer. 2. The silicon wafer transfer device according to claim 1, further comprising a foreign matter adsorbing means for adsorbing foreign matters in the transfer space by generating static electricity.   The silicon wafer transfer device has at least one second nozzle that jets gas to a side edge portion in the transfer direction of the wafer in the linear groove, and the second nozzle floats the wafer. 3. The silicon wafer according to claim 1, further comprising wafer stop means for stopping said wafer when said transferred wafer is at a transfer completion position by ejecting a gas having a pressure higher than that of said means. Conveying device.   The second nozzle is configured to be movable in the linear slot, and the first and second nozzles are arranged to sandwich the wafer, and the arrangement relationship between the first and second nozzles and the wafer is maintained. 4. The silicon wafer transfer apparatus according to claim 3, wherein the wafer is stably transferred by moving the first and second nozzles.   The silicon wafer transfer device further includes a circular groove hole at a predetermined position of the transfer table, the circular groove hole includes at least one third nozzle, and the third nozzle is a hole of the wafer floating means. 5. The method according to claim 1, further comprising wafer rotating means for rotating the wafer by moving the circular groove hole while jetting a gas having a pressure higher than that of the gas jetted from the wafer. The silicon wafer transfer device according to the item.

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