TWI839120B - Carrier for double-sided polishing of silicon wafer, double-sided polishing device and silicon wafer - Google Patents

Abstract

The present invention discloses a carrier, a double-sided polishing device and a silicon wafer for double-sided polishing of a silicon wafer; the carrier comprises: a first body in the shape of a disk and having a circular opening; a second body arranged in the circular opening of the first body, the second body being configured to be removable from the first body; a buffer unit arranged in a circle in the second body and in the shape of a ring, for forming a retaining hole for carrying the silicon wafer; wherein, before double-sided polishing is performed, the second body is removed from the first body and pre-treated to reduce its own temperature.

Description

Carrier for double-sided polishing of silicon wafer, double-sided polishing device and silicon wafer

The present invention belongs to the field of silicon wafer processing technology, and particularly relates to a carrier for double-sided polishing of a silicon wafer, a double-sided polishing device and a silicon wafer.

In recent years, with the development of the semiconductor industry, higher requirements have been placed on the flatness of silicon wafers. In the process of silicon wafer manufacturing, the flatness of silicon wafers can be improved through polishing technology. The polishing technology of silicon wafer surface usually includes double-sided polishing technology for polishing both the front and back sides of the silicon wafer and final polishing technology for polishing only the front side of the silicon wafer.

In the double-sided polishing technology, the front and back sides of the silicon wafer placed in the carrier are polished simultaneously by the polishing pads set on the upper and lower platens. However, during the double-sided polishing process, the polishing liquid will gather at the edge of the silicon wafer in the gap between the circular opening of the carrier and the edge of the silicon wafer, so that the content of polishing liquid in the side area of the silicon wafer is greater than that in other areas, resulting in a greater degree of polishing of the edge of the silicon wafer; on the other hand, due to the double-sided polishing process The carrier rotates around the central drive axis and thus drives the silicon wafer to rotate. The centrifugal force will also cause the polishing liquid to gather at the edge of the silicon wafer. In this case, the polishing degree of the edge of the silicon wafer will increase. Therefore, the polishing degree of the edge of the silicon wafer is greater than that of the middle area, resulting in the deterioration of the flatness of the edge of the silicon wafer.

In view of this, the present invention is intended to provide a carrier, a double-sided polishing device and a silicon wafer for double-sided polishing of a silicon wafer; the polishing degree of the edge of the silicon wafer can be reduced, thereby reducing the difference in polishing degree between the edge area and the middle area of the silicon wafer to improve the flatness of the edge and the entire silicon wafer.

The technical solution of the present invention is implemented as follows: In the first aspect, the present invention provides a carrier for double-sided polishing of silicon wafers, and the carrier for double-sided polishing of silicon wafers includes: a first body in the shape of a disk and having a circular opening; a second body arranged in the circular opening of the first body, and the second body is configured to be removable from the first body; a buffer unit arranged in a circle around the second body and in the shape of a ring, used to form a retaining hole for supporting the silicon wafer; wherein, before double-sided polishing, the second body is removed from the first body and pre-treated to reduce its own temperature.

In a second aspect, the present invention provides a device for double-sided polishing of silicon wafers, the device for double-sided polishing of silicon wafers comprising a plurality of carriers for double-sided polishing of silicon wafers according to the first aspect.

In a third aspect, the present invention provides a silicon wafer, which is obtained by double-sided polishing using the device for double-sided polishing of silicon wafers described in the second aspect.

The present invention provides a carrier for double-sided polishing of silicon wafers, a double-sided polishing device and a silicon wafer. For the carrier for double-sided polishing of silicon wafers provided by the present invention, the second body part in the carrier for double-sided polishing of silicon wafers is constructed to be able to be disassembled from the first body, and before double-sided polishing, the second body is disassembled from the first body and pre-treated, such as lowering its temperature, and at the same time, the second body whose temperature has been lowered is re-fixedly mounted on the first body during double-sided polishing. It can be understood that during the double-sided polishing process, the low temperature will contact the polishing liquid through the second body and the gap between the second body and the side of the silicon wafer, thereby reducing the temperature of the polishing liquid, thereby reducing the polishing rate of the polishing liquid and further reducing the polishing degree of the edge of the silicon wafer.

The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

Referring to FIG. 1 , a side cross-sectional view of the structure of a double-sided polishing device 1A is shown. FIG. 2 is a top view of the double-sided polishing device 1A shown in FIG. 1 , wherein FIG. 1 is a cross-sectional view along the R-R′ line in FIG. 2 . As shown in FIG. 1 and FIG. 2 , the double-sided polishing device 1A includes: an upper platen 10 and a lower platen 20 disposed opposite to each other in the upper and lower directions; a polishing pad 30, which is disposed below the upper platen 10 and above the lower platen 20, respectively; a center gear 40, which is mounted at the center portion between the upper platen 10 and the lower platen 20; an inner gear 50, which is mounted at the inner gear 50; and a lower gear 50, which is mounted at the inner gear 50. At the periphery between the upper platen 10 and the lower platen 20; a plurality of carriers 60A are arranged around the center gear 40, and the carrier 60A includes a body 601 with a circular opening and a circle of rubber rings 602 arranged around the circular opening. It can be understood that a circle of rubber rings 602 is arranged around the circular opening of the carrier 60A to form a holding hole 603 to carry the silicon wafer W to be polished. It can be understood that the silicon wafer W is sandwiched between the upper platen 10 and the lower platen 20 in a state of being installed in the holding hole 603 of the carrier 60A. It should be noted that, in FIG. 1 and FIG. 2 , only one retaining hole 603 is shown in each carrier 60A, but in actual production, a plurality of retaining holes 603 may be provided in each carrier 60A.

As shown in FIG2 , the outer peripheral gear 70 of each carrier 60A is engaged with each tooth portion of the center gear 40 and the inner gear 50, and the upper plate 10 and the lower plate 20 are driven to rotate by a driving device (not shown in the figure), whereby each carrier 60A revolves around the center gear 40 while rotating. At the same time, the silicon wafer W mounted in the holding hole 603 is held on the carrier 60A, and the front and back surfaces are polished simultaneously by contact with the polishing pad 30. During the polishing process, the polishing liquid is supplied to the polishing pad 30 from a nozzle (not shown in the figure).

It can be understood that when the silicon wafer W is loaded into the retaining hole 603 of the carrier 60A, the polishing liquid will gather between the circular opening of the carrier 60A and the edge of the silicon wafer W and in the gap above the rubber ring 602 during the double-sided polishing process, so that the content of polishing liquid in contact with the side area of the silicon wafer W is greater than that in other areas, thereby causing the edge of the silicon wafer W to be polished more than the other areas.

Based on the above description, refer to FIG. 3 , which shows a carrier 60 for double-sided polishing of a silicon wafer provided by an embodiment of the present invention. The carrier 60 for double-sided polishing of a silicon wafer specifically includes: a first body 301 in the shape of a disk and having a circular opening; a second body 302 arranged in the circular opening of the first body 301, and the second body is configured to be removable from the first body 301; a buffer unit in the shape of an annulus arranged around the second body 302, and used to form a retaining hole 603 for supporting the silicon wafer W; wherein, before double-sided polishing, the second body 302 is removed from the first body 301 and pre-treated to reduce its own temperature.

With respect to the carrier 60 for double-sided polishing of silicon wafers shown in FIG. 3 , the second body 302 in the carrier 60 for double-sided polishing of silicon wafers is partially constructed to be detachable from the first body 301, and before double-sided polishing, the second body 302 is detached from the first body 301 and pre-treated, such as by lowering its temperature, and at the same time, the second body 302 whose temperature has been lowered is re-fixedly mounted on the first body 301 during double-sided polishing. It can be understood that during the double-sided polishing process, the low temperature will contact the polishing liquid through the second body 302 and the gap between the second body 302 and the side of the silicon wafer W, thereby reducing the temperature of the polishing liquid, thereby reducing the polishing rate of the polishing liquid and further reducing the polishing degree of the edge of the silicon wafer.

For the carrier 60 for double-sided polishing of silicon wafers shown in FIG. 3 , in some possible implementations, the pre-treatment temperature of the second body is 15° C. to 20° C.

It should be noted that the pretreatment temperature of the second body 302 needs to be adjusted according to the flatness of the silicon wafers W after double-sided polishing of the previous batch, so as to control the double-sided polishing rate of the current silicon wafer W by adjusting the pretreatment temperature of the second body 302.

For the carrier 60 for double-sided polishing of silicon wafers shown in FIG. 3 , in some possible implementations, as shown in FIGS. 4 to 7 , a first protrusion 3021 or a first recess 3022 is provided on the circumferential outer edge of the second body 302 to respectively cooperate and connect with the corresponding second recess 3011 or second protrusion 3012 on the first body 301 .

For the carrier 60 for double-sided polishing of silicon wafers shown in FIG. 3 , in some possible implementations, the circumferential outer edge of the second body 302 is configured to be tooth-shaped so as to be engaged and connected with the corresponding tooth-shaped portion on the first body 301 .

In addition, for the carrier 60 for double-sided polishing of silicon wafers shown in FIG. 3 , in some possible implementations, the material of the second body 302 is stainless steel or ceramic.

On the other hand, for the carrier 60 for double-sided polishing of silicon wafers shown in FIG. 3 , in some possible implementations, the upper and lower surfaces of the second body 302 and the side surface in contact with the first body 301 are coated with a heat insulating material, and the heat insulating material is polyvinylidene fluoride (PVDF) or polyetherether ketone (PEEK). It can be understood that the surfaces of the second body 302 except the inner surface in contact with the buffer unit are coated with heat insulating material to prevent the temperature of the polishing pad 30 or the temperature of the polishing liquid acting on the front and back sides of the silicon wafer W or the temperature of the first body 301 from affecting the second body 302 during the double-sided polishing process, causing it to reach the same temperature as the first body 301 too quickly, thereby making it impossible to effectively cool down the polishing liquid in the gap between the second body 302 and the side of the silicon wafer W, and thus unable to effectively adjust the polishing rate.

Referring to FIG. 8 , it shows a device 1 for double-sided polishing of a silicon wafer provided by an embodiment of the present invention. The device 1 for double-sided polishing of a silicon wafer includes a plurality of carriers 60 for double-sided polishing of a silicon wafer according to the aforementioned technical solution.

Finally, the embodiment of the present invention provides a silicon wafer, which is mainly obtained by double-sided polishing using the device 1 for double-sided polishing of silicon wafers described in the aforementioned technical solution.

It should be noted that the technical solutions described in the embodiments of the present invention can be combined arbitrarily without conflict.

The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person familiar with the technical field and with ordinary knowledge within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the patent application.

1: Device for double-sided polishing of silicon wafers 1A: Double-sided polishing device 10: Upper platen 20: Lower platen 30: Polishing pad 301: First body 3011: Second concave portion 3012: Second convex portion 302: Second body 3021: First convex portion 3022: First concave portion 40: Center gear 50: Inner gear 60: Carrier for double-sided polishing of silicon wafers 60A: Carrier 601: Body 602: Rubber ring 603: Retaining hole 70: Peripheral gear

FIG1 is a side cross-sectional view of the structure of the double-sided polishing device in the conventional technical solution provided by the embodiment of the present invention; FIG2 is a top view of the double-sided polishing device shown in FIG1; FIG3 is a schematic diagram of the structure of a carrier for double-sided polishing of a silicon wafer provided by the embodiment of the present invention; FIG4 is a schematic diagram of the convex structure of the second body provided by the embodiment of the present invention; FIG5 is a schematic diagram of the concave structure of the first body provided by the embodiment of the present invention; FIG6 is a schematic diagram of the concave structure of the second body provided by the embodiment of the present invention; FIG7 is a schematic diagram of the convex structure of the second body provided by the embodiment of the present invention; FIG8 is a schematic diagram of the top view of the device structure for double-sided polishing of a silicon wafer provided by the embodiment of the present invention.

301: The first entity

302: Second body

60: Carrier for double-sided polishing of silicon wafers

60A: Vehicles

603:Holding hole

Claims (8)

A carrier for double-sided polishing of silicon wafers mainly comprises: a first body in the shape of a disk and having a circular opening; a second body arranged in the circular opening of the first body, the second body being configured to be removable from the first body; a buffer unit arranged around the second body and in the shape of a ring, used to form a holding hole for carrying the silicon wafer; wherein before double-sided polishing, the second body is removed from the first body and pre-treated to reduce its own temperature, and during double-sided polishing, the second body whose temperature has been reduced is re-fixedly mounted on the first body. The carrier for double-sided polishing of silicon wafers as described in claim 1, wherein the pretreatment temperature of the second body is 15°C~20°C. As described in claim 1, the carrier for double-sided polishing of silicon wafers, wherein the circumferential outer edge of the second body is provided with a first protrusion or a first recess, so as to respectively cooperate and connect with the corresponding second recess or second protrusion on the first body. A carrier for double-sided polishing of silicon wafers as described in claim 1, wherein the circumferential outer edge of the second body is configured to be tooth-shaped so as to engage and connect with the corresponding tooth-shaped portion on the first body. A carrier for double-sided polishing of silicon wafers as described in claim 1, wherein the material of the second body is stainless steel or ceramic. As described in claim 1, the carrier for double-sided polishing of silicon wafers, wherein the upper and lower surfaces of the second body and the side surface in contact with the first body are coated with a heat-insulating material, and the heat-insulating material is polyvinylidene fluoride or polyetheretherketone. A device for double-sided polishing of silicon wafers, mainly comprising a plurality of carriers for double-sided polishing of silicon wafers as described in any one of claims 1 to 6. A silicon wafer obtained by double-sided polishing using the device for double-sided polishing of silicon wafers as described in claim 7.

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