JP2005243994A - Device and method for polishing semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polishing device/method in polishing of a semiconductor wafer, without enlarging the device and with suppression of cost, and with which work efficiency can be improved. <P>SOLUTION: In the method, the semiconductor wafer stored in a box is conveyed to a polishing part 2 by a conveyance means so as to polish it, a temporary storage box 12, which temporarily stores the wafer before polishing is previously installed in a loader part 10; a box 11, where the wafer W to be polished is stored, is disposed in the loader; a part of the wafers W in the box is transferred to the polishing part, and polishing is started; all the wafers left in the box are transferred to the temporary storage box during polishing of the wafer. The box which becomes empty is exchanged with the next box where the new wafer is stored; and when polishing of the wafer is terminated, the wafer transferred to the temporary storing box is conveyed to the polishing part, and the next polishing is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polishing apparatus and a polishing method for a semiconductor wafer such as a silicon wafer.

  Conventionally, a single-side polishing apparatus and a double-side polishing apparatus have been used as apparatuses for polishing a semiconductor wafer such as a silicon wafer. As a general double-side polishing apparatus, a so-called four-way type apparatus 20 using a planetary gear mechanism as shown in FIGS. 3 and 4 is known.

  When the silicon wafer W is polished by such a double-side polishing apparatus 20, the wafer W is inserted and held in a plurality of wafer holding holes 28 formed in the carrier 21. Then, the wafer W in the holding hole is sandwiched between the upper surface plate 26a and the lower surface plate 26b to which the polishing cloths 27a and 27b are respectively attached, the polishing slurry is supplied through the slurry supply hole 23, and the carrier 21 is connected to the sun gear 24 and the internal gear. Rotate and revolve with the gear 25. Thereby, both surfaces of the wafer W in each holding hole can be polished simultaneously.

  As another type of double-side polishing apparatus, for example, as shown in FIGS. 5 and 6, the carrier 31 sandwiched between the upper and lower surface plates 36a and 36b (polishing cloths 37a and 37b) is not rotated. A device 30 that swings so as to draw a small circle is known (see Patent Document 1). A carrier 31 having a holding hole 34 is set in a carrier holder 38, and an eccentric arm 40 is rotatably attached to a bearing portion 39 of the holder 38. At the time of polishing, all the eccentric arms 40 are rotated in synchronization with the rotation shaft 41 via the timing chain 42, so that the carrier 31 held by the carrier holder 38 does not rotate and is a small circle in the horizontal plane. You can do a circular motion like drawing. Since the swing-type double-side polishing apparatus 30 can be downsized, the polishing operation can be performed in a relatively narrow space. With the recent increase in diameter of wafers, a oscillating double-side polishing apparatus 30 is often used.

  More specifically, the polishing procedure by the double-side polishing apparatus 30 will be described. For example, a box (generally called FOSB, FOUP, etc.) containing 25 wafers is an automatic transfer apparatus (AGV or the like). ) To a predetermined position and placed in a loading station (loader unit) of the double-side polishing apparatus. Next, after the wafer in the box is set in each holding hole 34 of the carrier 31, both surfaces of the wafer W are sandwiched between upper and lower surface plates 36a and 36b (polishing cloths 37a and 37b). The upper and lower surface plates 36 a and 36 b are rotated and the carrier 31 is swung to supply the polishing slurry from the slurry supply hole 33. The slurry reaches the lower polishing cloth 37b through the slurry passage hole 35 of the carrier 31, and both surfaces of the wafer W are simultaneously polished. After polishing for a predetermined time, the movement of the surface plates 36a and 36b and the carrier 31 is stopped. And the wafer W in the holding hole 34 is carried out to an unloading station (unloader part), maintaining a wet state, and is collect | recovered in a collection container.

  When polishing a wafer in the above-described procedure, normally, since all the wafers (for example, 25 sheets) in one box cannot be polished at a time, the processing is performed in a plurality of batches. For example, when a carrier having five holding holes as shown in FIG. 6 is used, the first five wafers are taken out of the box and set in each holding hole, and then polishing is started. The polishing time varies depending on the polishing apparatus to be used, polishing conditions, and the like, but it takes at least 30 minutes to process all the wafers in one box.

  When polishing a wafer as described above, conventionally, the wafer has been manually set in the holding hole of the carrier. However, in recent years, automation has progressed, and the loading of wafers in a box and unloading of wafers after polishing have been automatically performed by a transfer robot.

However, in conjunction with the automatic transfer device, when the system in which the wafer in the box is set in the polishing device by the transfer robot and the empty box is collected can be streamlined, the empty box can be streamlined. There is a problem that the time from collection to setting of a box containing a wafer to be processed next becomes a waiting time for the apparatus, and the operating rate is lowered.
In order to reduce the loss of the replacement time of the box, for example, it is conceivable to increase the number of automatic conveyance devices or to provide a plurality of loader units. However, this increases the size of the device and increases the equipment (device) cost.

JP-A-10-202511

  In view of the above problems, an object of the present invention is to provide a polishing apparatus and a polishing method capable of improving work efficiency while reducing the cost without increasing the size of the apparatus in polishing a semiconductor wafer. And

  According to the present invention, a semiconductor wafer having at least a loader unit, a transfer robot, a polishing unit, and an unloader unit, and housed in a box disposed in the loader unit, is transferred to the polishing unit by the transfer robot. In a polishing apparatus that transports and polishes the wafer to the unloader unit after polishing by the polishing unit, the wafer before polishing is transferred to the loader unit from a box disposed in the loader unit and temporarily stored. A semiconductor wafer polishing apparatus is provided in which a temporary storage box is installed (claim 1).

  If the polishing apparatus is provided with a temporary storage box in the loader portion in this way, the wafer remaining in the box is temporarily stored while the wafer first taken out from the box containing the wafer is being polished. The next polishing can be performed by removing the wafer from the temporary storage box. The box emptied by the transfer to the temporary storage box can be replaced with a box containing the next wafer. Thus, if the box is replaced after the wafer is transferred into the temporary storage box provided in the loader unit, the waiting time of the polishing unit is eliminated, and the efficiency of the polishing operation can be greatly improved. Further, if the polishing apparatus is provided with a temporary storage box in the loader unit, it is not necessary to increase the size of the apparatus as compared with the case where two or more of the same boxes are installed, and the apparatus is inexpensive.

In this case, the polishing apparatus is preferably a double-side polishing apparatus.
In recent years, a double-side polishing apparatus has been frequently used, and by using a double-side polishing apparatus in which a temporary storage box is installed in the loader section as described above, wafers can be polished more efficiently. It will also contribute to automation.

It is preferable that the temporary storage box and the box in which the wafer is accommodated are arranged on the same circumference around the transfer robot.
Thus, if the temporary storage box and the box containing the wafer are arranged on the same circumference, handling by the central transfer robot is facilitated, and the wafer can be transferred to the temporary storage box. It can be performed easily and quickly, and contributes to downsizing of the apparatus.

  Furthermore, according to the present invention, in the method of polishing by transferring the semiconductor wafer accommodated in the box to the polishing apparatus by the transfer means, the temporary storage box for temporarily storing the wafer before polishing in the loader section. Is placed in advance, the box containing the wafer to be polished is placed in the loader unit, a part of the wafer in the box is transferred to a polishing apparatus to start polishing, and during the polishing of the wafer All the wafers remaining in the box are transferred to the temporary storage box, the emptied box is replaced with the next box containing a new wafer, and when the polishing of the wafer is completed, A method for polishing a semiconductor wafer is provided, wherein the wafer transferred to the temporary storage box is transported to the polishing apparatus for subsequent polishing. Motomeko 4).

  While polishing the first batch of wafers in the box in this way, the wafer remaining in the box is transferred to the temporary storage box and the empty box is replaced. This eliminates the waiting time for improving the efficiency of the polishing operation.

In this case, it is preferable to use a double-side polishing apparatus as the polishing apparatus.
If a double-side polishing apparatus provided with a temporary storage box according to the present invention is used, double-side polishing of a wafer that has recently been required can be performed more efficiently.

It is preferable that the temporary storage box and the box in which the wafer is accommodated are arranged on the same circumference centering on the conveying means.
In this way, if the temporary storage box and the box containing the wafer are arranged on the same circumference, handling by the central transfer robot is facilitated, and the wafer can be easily and quickly transferred to the temporary storage box. Can be done.

  According to the present invention, a temporary storage box is provided in advance in the loader portion of the polishing apparatus, and the first batch of wafers taken out from the box containing the wafer to be polished is left in the box while being polished. The wafer is transferred to a temporary storage box, and the empty box is replaced with the next box. If the emptied box is replaced with the next box in advance after the wafer is transferred into the temporary storage box in this way, the waiting time of the polishing apparatus associated with the replacement of the box is eliminated, and the efficiency of the polishing work is improved. It can be greatly improved. Also, compared to the case where two loader units are provided and the wafer is transferred from each box arranged in each loader unit by the transfer robot, the apparatus can be downsized and the equipment cost can be kept low. be able to.

Hereinafter, as a preferred embodiment of the present invention, a case where a silicon wafer is polished on both sides will be described in detail with reference to the accompanying drawings.
When automating the polishing operation of the semiconductor wafer, the present inventor waits after the box of the loader unit is emptied until it is recovered and placed in the next box, that is, the loader unit. We focused on reducing the operating rate at the rate-limiting step. In order to reduce or eliminate such a waiting time, for example, a plurality of loading stations may be provided in one polishing apparatus, and two or more boxes containing wafers may be arranged. However, in this case, the apparatus becomes larger, and two openers are required to open the lid of each box, and it is necessary that all of the box conveying device, the wafer conveying device, etc. correspond to two or more. The cost will rise remarkably.

  Therefore, as a result of further intensive studies, the present inventor has installed a temporary storage box (also referred to as “buffer” in the present invention) in the loader unit, so that the apparatus is not increased in size and cost. It has been found that the work efficiency can be greatly improved while keeping the above low. That is, after polishing starts, the wafer remaining in the box is quickly transferred to the buffer, and if the emptied box is replaced with the next box, the size of the apparatus is not increased and the cost is not increased. It has been found that the work efficiency can be improved by eliminating the waiting time for the replacement of boxes, and the present invention has been completed. In this case, since the boxes to be taken in and out of the loader unit need only be carried out one by one, a new box transport device, an opener or the like is not necessary.

FIG. 1 is a diagram showing an outline of an example of an apparatus according to the present invention.
The double-side polishing apparatus 1 includes a polishing apparatus main body (polishing unit) 2, a loading station (loader unit) 10, an unloader unit 16, and the like. The polishing apparatus main body 2 is an oscillating type having an eccentric arm 7, a carrier holder 3, etc., and the carrier 4 is provided with five wafer holding holes 5 and a slurry passage hole 6. A box 11 (hereinafter also referred to as “accommodating box”) containing a silicon wafer W before polishing is disposed in the loader unit 10, and a collection container (water tank) that collects the wafer after polishing is disposed in the unloader unit 16. ) 17 is arranged.

  Further, a transfer robot 13 is provided as a transfer means for the wafer W. The transfer robot 13 can move up and down, right and left, and can be rotated. In particular, as shown in FIG. 2, the transfer robot 13 is hung from the upper frame 19 in the polishing apparatus and has the joint portion 8. This is also suitable for preventing interference with the unloader unit 16 and the like installed at the lower part.

In the polishing apparatus 1, a fixed temporary storage box (buffer) 12 is installed in the loader unit 10 separately from the box 11 in which the wafer W is accommodated. The buffer 12 may be a front open container in which a groove is formed in the buffer so that the same number of wafers W as the box 11 in which the wafer W is accommodated can be held horizontally. For example, FOSB made of polycarbonate without a lid can be used, and it is assumed that it is fixed to the loader unit 10 with pins or the like so as to be detachable. Further, the buffer 12 is arranged on the same circumference centering on the transfer robot 13 when the box 11 containing the wafer W is arranged in the loader unit 10. Such a buffer 12 is not necessarily arranged as shown in FIG. 1, and may be installed so as to be transported by the transport robot 13.
Although not shown, upper and lower surface plates, polishing cloths, slurry supply means and the like necessary for a double-side polishing apparatus are also provided.

  In order to polish a silicon wafer with such a polishing apparatus 1, first, a box 11 (for example, 25 sheets) containing a wafer W to be polished is carried by a box automatic transfer device 14 and arranged on a loader unit 10. Is done. The method of transporting the box 11 to the loader unit 10 is not particularly limited. In addition to a method of transporting by a self-propelled transport vehicle (AGV) that travels on the floor surface, a rail is attached to the ceiling of the room. It is good also as a system (OHT) which lays and conveys a box along a rail.

  The box 11 disposed in the loader unit 10 has its lid opened by an opener or the like, and the wafer W in the box 11 is held by the transport robot 13. For example, as shown in FIG. 2, a plate-like holding means 9 is provided at the tip of the transfer robot 13, and the lower surface side of the wafer W accommodated horizontally in the box 11 is scooped up horizontally. Can be held.

  Next, the wafer W is transported to the carrier 4 and set in the holding hole. As shown in FIG. 1, a table (centering stage 15) for changing the wafer W before setting in the holding hole. Etc. may be provided. After the wafer W holding the lower surface side is once placed on the centering stage 15, the wafer can be held more reliably by holding the upper surface side central portion of the wafer by holding means, for example, by suction. Insertion into the hole 5 is also facilitated. If the transfer robot 13 is provided with a holding means by suction in addition to the plate-like holding means 9, the wafer W can be changed by one unit, the polishing apparatus can be made smaller and the cost can be further increased. Can be suppressed.

  As described above, the wafer W is taken out from the box 11 and set in the holding holes 5 in sequence, and then the upper surface plate is lowered to sandwich the wafer in the holding hole 5 between the upper and lower polishing cloths. Next, polishing slurry is supplied, and polishing of the wafers for the first batch is started by rotating the upper and lower surface plates (polishing cloth) and swinging the carrier 4.

  Here, although a large number of wafers still remain in the storage box 11, the wafer W remaining in the box 11 is buffered before the polishing is finished after the polishing of the wafers for the first batch is started. To 12. In this case, the back side of the wafer in the storage box 11 is held by being picked up by the transfer robot 13 and transferred to the buffer 12 without changing. At this time, since the storage box 11 and the buffer 12 are arranged on the same circumference centering on the transfer robot 13, the transfer from the storage box 11 to the buffer 12 can be easily performed by rotation around the axis of the transfer robot 13. And can be done quickly.

  All the wafers remaining in the storage box 11 are quickly transferred to the temporary storage box 12 to empty the storage box 11. The emptied box 11 is collected, and the next box containing a new wafer is placed in the loader unit 10. In this way, when the wafer W accommodated in the previous box is transferred to the buffer 12 and the box is exchanged while the wafer W is being polished, the conventional box replacement can be performed. The waiting time can be eliminated. In this case, of course, the wafer transfer and the box replacement need not be performed only during the first polishing, and it is only necessary to prevent the waiting time for polishing due to the replacement of the box, so that two batches are required. When there are eyes and third batches, the wafers may be transferred and the boxes may be replaced using the polishing time.

  In the polishing apparatus main body 2, when the polishing of the wafer for the first batch is completed, the operation of the surface plate and the carrier 4 is stopped, and the wafer is recovered. That is, the wafer is taken out from the carrier 4 by the holding means by suction and sequentially carried out to the collection container (water tank) 17 of the unloader unit 16. The wafer is preferably collected by the transfer robot 13 having the holding means by suction as described above, but a collection transfer robot may be provided separately.

  After the wafer in the carrier 4 is collected, the next polishing is performed. At this time, the wafer is taken out from the buffer 12, polished in the same manner, and then collected in the collection container 17. All the wafers in the buffer 12 are also polished, and the wafers collected in the collection container 17 are carried to the next process (cleaning) by the automatic conveyance device (AGV) 18.

  When the polishing of all the wafers in one box is completed as described above, a new box 11 has already been placed in the loader unit 10, so there is no waiting time due to the replacement of the boxes, and there is no continuous waiting time. Polishing work can be performed. Here, the wafer in the new box may be polished by the same procedure as in the previous box. That is, the wafer is taken out from the new storage box by the transfer robot 13, set in the holding hole 5 of the carrier 4, and polishing for the first batch is started. During polishing, the wafer remaining in the box is transferred into the buffer 12, and the emptied box 11 is further replaced with the next box.

  As described above, in the present invention, the buffer 12 is installed in the loader unit 10 in advance, and the wafer is taken out from the storage box 11 arranged in the loader unit 10 to polish the first batch. During polishing, the wafer remaining in the box 11 is transferred into the buffer 12, and the emptied box 11 is replaced with a new box. By repeating such a series of operations and polishing the wafer, the waiting time for replacing the box can be eliminated as before, and the wafer polishing operation can be performed continuously, greatly improving the work efficiency. Can be made.

  In the polishing apparatus according to the present invention, the buffer 12 is fixed to the loader unit 10 and does not need to be replaced. Therefore, for example, compared with the case where two loader units are provided and a wafer is transferred from each box arranged in each loader unit by a transfer robot, the apparatus can be downsized and the equipment can be reduced. Cost can be kept low. As a result, it greatly contributes to the full automation of the polishing process.

  The present invention is not limited to the above embodiment. The above embodiment is merely an example, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same operational effects. It is included in the technical scope of the invention.

  For example, in the above-described embodiment, the swing type double-side polishing apparatus has been described. However, the present invention is not limited to this, and can be applied to a 4-way double-side polishing apparatus or a single-side polishing apparatus. Further, the arrangement in the polishing apparatus is not limited to that shown in FIG.

It is the schematic which shows an example of the grinding | polishing apparatus which concerns on this invention. It is the schematic which shows an example of a conveyance robot. It is a schematic diagram showing an example of a 4-way double-side polishing apparatus. It is a schematic plan view which shows a planetary gear structure. It is the schematic of a rocking | swiveling type double-side polish apparatus. FIG. 6 is a schematic plan view of a carrier holder in the double-side polishing apparatus of FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Double-side polish apparatus, 2 ... Polishing apparatus main body, 3 ... Carrier holder, 4 ... Carrier,
5 ... Holding hole, 6 ... Slurry passage hole, 7 ... Eccentric arm, 8 ... Joint part,
9 ... Wafer holding means, 10 ... Loader, 11 ... Wafer storage box,
12 ... Temporary storage box (buffer), 13 ... Transport robot,
14 ... Box automatic transfer device, 15 ... Centering stage,
16 ... unloader part, 17 ... collection container (water tank), 18 ... automatic transfer device,
19 ... Frame, W ... Wafer.

Claims (6)

  At least a loader unit, a transfer robot, a polishing unit, and an unloader unit. The semiconductor robot accommodated in a box arranged in the loader unit is transferred to the polishing unit by the transfer robot, and the polishing unit In the polishing apparatus that transports the wafer to the unloader unit after polishing at the loader unit, the loader unit is provided with a temporary storage box for temporarily storing the wafer before polishing from within the box disposed in the loader unit. An apparatus for polishing a semiconductor wafer, wherein:   The semiconductor wafer polishing apparatus according to claim 1, wherein the polishing apparatus is a double-side polishing apparatus.   3. The semiconductor wafer polishing apparatus according to claim 1, wherein the temporary storage box and the box in which the wafer is accommodated are arranged on the same circumference centered on the transfer robot. 4. .   In the method for carrying out the polishing by transferring the semiconductor wafer accommodated in the box to the polishing apparatus by the transfer means, a temporary storage box for temporarily storing the wafer before polishing in the loader part is installed in advance, A box containing a wafer to be polished is placed in the loader unit, a part of the wafer in the box is transferred to a polishing apparatus to start polishing, and all remaining in the box during polishing of the wafer The wafer was transferred to the temporary storage box, the emptied box was replaced with a next box containing a new wafer, and when the wafer was polished, it was transferred to the temporary storage box. A method for polishing a semiconductor wafer, comprising transporting a wafer to the polishing apparatus and performing the next polishing.   The method for polishing a semiconductor wafer according to claim 4, wherein a double-side polishing apparatus is used as the polishing apparatus.   6. The method for polishing a semiconductor wafer according to claim 4, wherein the temporary storage box and the box in which the wafer is accommodated are arranged on the same circumference centering on the transfer means.

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