TWI897494B - Grinding system and grinding plate assembly - Google Patents

Abstract

A grinding system includes a rotation device, a grinding plate assembly, a dresser and at least one wafer carrier. The grinding plate assembly includes a substrate and a plurality of abrasive units. The substrate includes a mount portion and a support portion. The mount portion and the support portion are integrally formed as one piece, and the coefficient of thermal expansion of the substrate falls within a range from 2×10 ^-6to 12×10 ^-6. The mount portion is mounted on the rotation device for being rotated by the rotation device. The abrasive units are removably disposed on the support portion. The dresser is located above the substrate. The wafer carrier is configured to support the wafer and is located above the substrate. The wafer carrier and the dresser respectively correspond to different positions of the substrate. The dresser and the wafer on the wafer carrier contact the abrasive units of the grinding plate assembly simultaneously or in turn, such that the dresser dresses the abrasive units, and the abrasive units grinds the wafer.

Description

Wafer polishing system and polishing plate assembly

The present invention relates to a wafer polishing system and a polishing plate assembly.

Current wafer polishing equipment installs the base and emery plate separately. Once the base is locked to the rotating machine, it remains in place, while the emery plate is frequently removed and reassembled to bond the emery strips. This practice can easily affect the flatness between the emery plate and the base. Furthermore, the base and emery plate are mostly made of metal, which has a high thermal expansion coefficient. This can easily cause slight deformation during the polishing process due to heat, which in turn affects wafer polishing accuracy.

The present invention provides a wafer polishing system and a polishing plate assembly that can maintain the polishing accuracy of wafers.

An embodiment of the present invention discloses a wafer polishing system for polishing at least one wafer. The wafer polishing system includes a rotating device, a grinding disc assembly, a dresser, and at least one wafer carrier. The grinding disc assembly includes a base and a plurality of polishing units. The base includes an assembly portion and a supporting portion, the assembly portion and the supporting portion are integrally formed, the thermal expansion coefficient of the base falls within the range of 2× ^10-6 to 12× ^10-6 , the assembly portion is assembled to the rotating device and rotated by the driving of the rotating device, and the polishing units are arranged on the supporting portion. The dresser is located above the base. The wafer carrier carries the wafer and is located above the base, and the wafer carrier and the dresser respectively correspond to different portions of the base. The dresser and the wafer on the wafer carrier are used to contact the polishing units of the grinding plate assembly simultaneously or alternately, so that the dresser dresses the polishing units and the polishing units polish the wafer.

Another embodiment of the present invention discloses a grinding wheel assembly for being arranged in a rotating device and for a dresser to dress and grind at least one wafer on at least one wafer carrier. The grinding wheel assembly includes a base and a plurality of grinding units. The base includes an assembly portion and a supporting portion, and the assembly portion and the supporting portion are integrally formed. The thermal expansion coefficient of the base falls within the range of 2× ^10-6 to 12× ^10-6 . The assembly portion is used to be assembled in the rotating device and rotated by the driving of the rotating device. These grinding units are arranged in the supporting portion, and these grinding units are used to contact the dresser and the wafers on the wafer carrier simultaneously or alternately, so that the dresser dresses these grinding units and the grinding units grind the wafers.

According to the wafer polishing system and grinding wheel assembly disclosed in the above-mentioned embodiments, the assembly portion and the supporting portion of the grinding wheel assembly base are integrally formed, and the thermal expansion coefficient of the base is configured within the range of 2× ^10-6 to 12× ^10-6 . This ensures that no assembly is required between the assembly portion and the supporting portion, thereby preventing assembly errors and affecting flatness. In addition, the heat generated during the polishing process is unlikely to deform the base, thereby maintaining the polishing accuracy of the grinding wheel assembly for the wafer.

The above description of the present invention and the following description of the embodiments are intended to demonstrate and explain the principles of the present invention and to provide further explanation of the scope of the patent application of the present invention.

1: Wafer polishing system

10: Rotating device

11: Rotation axis

20: Grinding disc assembly

21: Seat

211: Assembly Department

212: Carrying section

2121: Surface

22: Grinding unit

30: Dresser

40: Wafer carrier

W: Wafer

C: Centerline

S11~S12: Steps

Figure 1 is a schematic perspective view of a wafer polishing system according to one embodiment of the present invention.

Figure 2 is a schematic cross-sectional view of the wafer polishing system in Figure 1.

Figure 3 is a flow chart of a wafer polishing method used in conjunction with the wafer polishing system of Figure 1.

Figure 4 shows a cross-sectional view of the dresser and the wafer on the wafer carrier in Figure 2 contacting the polishing unit simultaneously.

Figures 5 and 6 show schematic cross-sectional views of the dresser and wafer on the wafer carrier of Figure 2 contacting the polishing unit in turn.

Please refer to Figures 1 and 2. Figure 1 is a schematic perspective view of a wafer polishing system according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view of the wafer polishing system of Figure 1.

In this embodiment, a wafer polishing system 1 is used to polish a wafer W. The wafer polishing system 1 includes a rotating device 10, a grinding plate assembly 20, a dresser 30, and a wafer carrier 40.

The rotating device 10 has a rotating shaft 11. The grinding disc assembly 20 includes a base 21 and a plurality of grinding units 22. The base 21 includes an assembly portion 211 and a supporting portion 212, and the assembly portion 211 and the supporting portion 212 are integrally formed. The thermal expansion coefficient of the base 21 falls within the range of 2× ^10-6 to 12× ^10-6 , and the elastic modulus of the base 21 falls within the range of 50GPa to 400GPa, for example but not limited to. For example, the material of the base 21 is silicon carbide, aluminum oxide, granite or artificial granite. The assembly portion 211 is, for example, directly fixed to the rotating shaft 11, and can be rotated about the center line C of the rotating shaft 11 by being driven by the rotating device 10. The polishing units 22 are structures such as abrasive strips or grinding blocks suitable for polishing the wafer W. The polishing units 22 are, for example, bonded to a surface 2121 of the support portion 212 that is distal from the assembly portion 211, but are not limited thereto. In other embodiments, the polishing units may be secured to the support portion by other suitable means, such as inlaying or latching.

In this embodiment, the base 21 is made of, for example, silicon carbide, aluminum oxide, granite, or artificial granite, so that the base 21 has sufficient rigidity, thermal stability, and chemical resistance to maintain the grinding accuracy of the grinding units 22 on the support portion 212.

The dresser 30 and wafer carrier 40 are positioned above the support portion 212 of the base 21. In other words, the dresser 30 and wafer carrier 40 are positioned on the side of the support portion 212 facing the surface 2121 of the support portion 212. The dresser 30 and wafer carrier 40 correspond to different portions of the support portion 212. For example, the dresser 30 and wafer carrier 40 are positioned evenly above the support portion 212 of the base 21. In other words, the dresser 30 and wafer carrier 40 are symmetrically positioned relative to the centerline C of the rotation shaft 11 of the rotating device 10. Specifically, the dresser 30 and wafer carrier 40 are located on opposite sides of the centerline C of the rotating shaft 11 of the rotating device 10, such that the dresser 30 and wafer carrier 40 correspond to opposite sides of the support portion 212. The dresser 30 and wafer carrier 40 can move toward or away from the support portion 212 in a direction parallel to the rotational axis of the polishing plate assembly 20 (i.e., the centerline C of the rotating shaft 11).

In this embodiment, the dresser 30 is used to dress the polishing units 22 of the polishing plate assembly 20 , which polish the wafer W on the wafer carrier 40 . The following describes a wafer polishing method used with the wafer polishing system 1 . See Figure 4 , which is a flow chart of the wafer polishing method used with the wafer polishing system.

First, in step S11, the rotating device 10 is activated to rotate the grinding plate assembly 20. Next, in step S12, the dresser 30 and the wafer W on the wafer carrier 40 are simultaneously brought into contact with the grinding units 22 of the grinding plate assembly 20. The dresser 30 dresses the grinding units 22, and the grinding units 22 grind the wafer W.

In this embodiment, the dresser 30 and the wafer W on the wafer carrier 40 are simultaneously brought into contact with the polishing units 22 of the grinding plate assembly 20. This allows the polishing units 22 to be simultaneously polished by the dresser 30 while polishing the wafer W, maintaining the desired polishing accuracy of the wafer W.

In this embodiment, the assembly portion 211 and the supporting portion 212 of the base 21 of the grinding wheel assembly 20 are integrally formed, and the thermal expansion coefficient of the base 21 is configured within the range of 2× ^10-6 to 12× ^10-6. This ensures that no assembly is required between the assembly portion 211 and the supporting portion 212, thereby preventing assembly errors and affecting flatness. Furthermore, the heat generated during the grinding process is unlikely to deform the base 21, thereby maintaining the grinding accuracy of the grinding wheel assembly 20 for the wafer W.

On the other hand, by integrally forming the assembly portion 211 and the supporting portion 212 of the base 21 of the grinding wheel assembly 20, the assembly portion 211 and the supporting portion 212 can be assembled to the rotating device 10 in a single assembly process, thereby saving assembly time.

Furthermore, by ensuring that the elastic modulus of the base 21 of the grinding wheel assembly 20 falls within the range of 50 GPa to 400 GPa, the rigidity of the base 21 is ensured, further maintaining the grinding accuracy of the grinding wheel assembly 20 on the wafer W.

In step S12, the dresser 30 and the wafer W on the wafer carrier 40 are simultaneously brought into contact with the polishing units 22 of the grinding plate assembly 20, but this is not limiting. For example, the dresser 30 and the wafer W on the wafer carrier 40 may alternately contact the grinding units 22 of the grinding plate assembly 20 in a direction parallel to the rotational axis of the grinding plate assembly 20. For details, see Figures 5 and 6, which illustrate the cross-sectional schematic diagrams of Figure 2 showing the dresser and the wafer on the wafer carrier alternately contacting the grinding units. During the wafer polishing process in the wafer polishing system 1, while the dresser 30 contacts the polishing cells 22 of the grinding plate assembly 20, the wafer W on the wafer carrier 40 is lifted up and no longer in contact with the grinding plates 20. Then, after a preset time, the wafer W on the wafer carrier 40 contacts the grinding plates 20, while the dresser 30 is lifted up and no longer in contact with the grinding plates 20. This allows the polishing cells 22 to be instantly trimmed by the dresser 30, maintaining the desired polishing accuracy for the wafer W.

It should be noted that the wafer polishing system 1 is not limited to including a single wafer carrier 40. In other embodiments, the wafer polishing system may include multiple wafer carriers. These wafer carriers and the dresser may be evenly positioned above the base of the polishing plate assembly, for example. In other words, the angles between any two adjacent wafer carriers and dressers are equal. Furthermore, each wafer carrier is not limited to carrying a single wafer. In other embodiments, each wafer carrier may carry multiple wafers.

According to the wafer polishing system and grinding wheel assembly disclosed in the above-mentioned embodiments, the assembly portion and the supporting portion of the grinding wheel assembly base are integrally formed, and the thermal expansion coefficient of the base is configured within the range of 2× ^10-6 to 12× ^10-6 . This ensures that no assembly is required between the assembly portion and the supporting portion, thereby preventing assembly errors and affecting flatness. In addition, the heat generated during the polishing process is unlikely to deform the base, thereby maintaining the polishing accuracy of the grinding wheel assembly for the wafer.

On the other hand, the integrated assembly and support components of the grinding wheel assembly's base allow them to be assembled to the rotating device in a single process, saving assembly time.

Furthermore, by ensuring the elastic modulus of the grinding wheel assembly's base falls within the range of 50 GPa to 400 GPa, the base's rigidity is ensured, further maintaining the grinding accuracy of the grinding wheel assembly on wafers.

Furthermore, the base of the grinding wheel assembly is made of a material such as silicon carbide, aluminum oxide, granite, or artificial granite, so that the base has sufficient rigidity, thermal stability, and chemical resistance to maintain the grinding accuracy of the grinding units on the base's support portion.

Furthermore, during the wafer polishing process, the dresser and the wafer on the wafer carrier are brought into contact with the polishing units of the grinding plate assembly simultaneously or alternately. This allows these polishing units to be trimmed by the dresser in real time, maintaining the required polishing accuracy for the wafers.

Although the present invention is disclosed above with reference to the preferred embodiments, they are not intended to limit the present invention. Anyone skilled in the art may make minor modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of patent protection for the present invention shall be determined by the scope of the patent application attached to this specification.

1: Wafer polishing system

10: Rotating device

11: Rotation axis

20: Grinding disc assembly

21: Seat

211: Assembly Department

212: Carrying section

2121: Surface

22: Grinding unit

30: Dresser

40: Wafer carrier

W: Wafer

C: Centerline

Claims (10)

A wafer polishing system for polishing at least one wafer comprises: a rotating device; a polishing plate assembly comprising a base and a plurality of polishing units; the base comprising an assembly portion and a supporting portion, the assembly portion and the supporting portion being integrally formed; and a thermal expansion coefficient of the base ranging from 2×10 ^-6 to 12×10 ^-6 , the assembly part is assembled to the rotating device and rotated by the driving of the rotating device, the grinding units are arranged on the supporting part; a dresser is located above the base; and at least one wafer carrier carries the at least one wafer and is located above the base, the at least one wafer carrier and the dresser respectively correspond to different places of the base; wherein the dresser and the at least one wafer on the at least one wafer carrier are used to simultaneously contact the grinding units of the grinding disc assembly, so that the dresser dresses the grinding units and the grinding units grind the at least one wafer. The wafer polishing system of claim 1, wherein the elastic modulus of the base is in the range of 50 GPa to 400 GPa. The wafer polishing system as described in claim 1, wherein the material of the base is silicon carbide, aluminum oxide, granite or artificial granite. The wafer polishing system as described in claim 1, wherein the polishing units are bonded to the supporting portion. The wafer polishing system as described in claim 1, wherein the rotating device has a rotating shaft, the assembly part is directly fixed to the rotating shaft, and the dresser and the at least one wafer carrier are evenly located above the base. The wafer polishing system as described in claim 1, wherein the dresser and the at least one wafer on the at least one wafer carrier are used to simultaneously contact the polishing units of the polishing plate assembly along a direction parallel to the rotation axis of the polishing plate assembly. A grinding wheel assembly is provided for placement on a rotating device and for use by a dresser to dress and polish at least one wafer on at least one wafer carrier. The grinding wheel assembly comprises: a base comprising an assembly portion and a support portion, the assembly portion and the support portion being integrally formed and configured to be assembled to the rotating device and rotated by the rotating device; the base having a thermal expansion coefficient within a range of 2× ^10-6 to 12× ^10-6 ; and a plurality of polishing units disposed on the support portion. The polishing units are configured to simultaneously contact the dresser and the at least one wafer on the at least one wafer carrier, allowing the dresser to dress the polishing units and the polishing units to polish the at least one wafer. The grinding disc assembly as described in claim 7, wherein the elastic modulus of the base body falls within the range of 50 GPa to 400 GPa. The grinding disc assembly as described in claim 7, wherein the base is made of silicon carbide, aluminum oxide, granite or artificial granite. The grinding disc assembly as described in claim 7, wherein the grinding units are bonded to the supporting portion.