Wafer edge polishing method and polishing apparatus

Abstract

The application discloses a wafer edge polishing method and a polishing device. The wafer edge polishing device comprises a rotating mechanism for loading a wafer and rotating the wafer around a central axis, a polishing head for pressing a polishing belt against an edge portion of the wafer, the polishing head is moved in a horizontal direction and / or swings around a fixed point to form a ring-shaped opening on the wafer edge, and at least a part of the polishing head is a non-planar structure, so that the ring-shaped opening formed is free of angular structure.

Description

[0001] This application is a divisional application of the invention patent application with application number 202411959835X, filed on December 30, 2024. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the technical field of semiconductor manufacturing, and in particular to a wafer edge polishing method and a polishing device. BACKGROUND

[0003] In semiconductor processing technology, it is necessary to form a step shape on the edge of a wafer to form a trim wafer, thereby reducing the risk of cracks or edge collapse in subsequent processing such as bonding.

[0004] Wafer edge cutting can use a grinding wheel to abut the edge of the wafer, such as the technical solution disclosed in patent CN111403315A, to process the edge of the wafer to a shape and size that meets the process requirements; wafer edge cutting can also use a polishing belt to abut the edge of the wafer, such as the technical solution disclosed in patent US20140213152A1, to form a step shape on the edge of the wafer.

[0005] However, the existing wafer edge cutting method can form a trim wafer, but the step shape has a right-angle cross-sectional shape, which has a stress concentration problem and is prone to edge collapse, resulting in debris and cracks, which will affect the yield of wafer processing.

[0006] When wafer edge cutting is performed, the side surface of the grinding wheel or polishing belt directly contacts the side surface of the formed step structure, and the side surface of the grinding wheel or polishing belt is a non-process surface, which will affect the forming quality of the side surface of the step structure, and the side surface of the step structure will appear uneven, as shown in Figure 12 In the subsequent wafer bonding process, debris will fall off from the side surface of the step structure, thereby affecting the effect of wafer bonding.

[0007] In addition, the side surface of the step structure is uneven, which is prone to attach a small amount of particulate matter. Due to the large roughness of the side surface, it will increase the adhesion strength of the particulate matter, thereby increasing the difficulty of cleaning the edge of the trim wafer. SUMMARY

[0008] Therefore, embodiments of the present application provide a wafer edge polishing method and a polishing device to at least partially solve the above problems.

[0009] According to a first aspect of embodiments of the present application, a wafer edge polishing device is provided, comprising:

[0010] a rotating mechanism for loading a wafer and rotating the wafer around a central axis;

[0011] a polishing head that presses the polishing tape against the edge portion of the wafer;

[0012] the polishing head moves in a horizontal direction and / or swings around a fixed point to form a ring-shaped opening at the edge of the wafer; at least a portion of the polishing head is non-planar, so that the ring-shaped opening formed is free of angular structures;

[0013] the polishing head includes an inclined portion and a circular arc portion; the inclined portion extends upward from the bottom surface of the polishing head and away from the central axis of the rotating mechanism, to guide the polishing tape upward and outward; the circular arc portion is arranged opposite the inclined portion, to eliminate angular structures of the ring-shaped opening.

[0014] In some embodiments, the polishing head is configured with a vertical driving mechanism to move the polishing head along the length of the output shaft of the vertical driving mechanism; the vertical driving mechanism is arranged on a fixed base, which is arranged laterally of the rotating mechanism.

[0015] In some embodiments, the vertical driving mechanism is connected to a horizontal driving mechanism via a support, and the horizontal driving mechanism moves the fixed base and the polishing head thereon horizontally, to approach or move away from the edge portion of the wafer.

[0016] In some embodiments, the wafer edge polishing device further includes a swing driving mechanism connected to the fixed base, to swing the fixed base and the polishing head thereon, to change the contact state of the polishing head with the edge portion of the wafer.

[0017] In some embodiments, the polishing head further includes a pressing portion arranged between the inclined portion and the circular arc portion, to press downward via the polishing tape, to further feed the edge portion of the wafer vertically.

[0018] In some embodiments, the angle between the inclined portion and the horizontal plane is 15-70°.

[0019] In some embodiments, the horizontal width of the pressing portion is 1-6 mm.

[0020] According to a second aspect of the embodiments of the present application, a wafer edge polishing method is provided, which uses the wafer edge polishing device described above, and includes:

[0021] the rotating mechanism loads the wafer and rotates the wafer around the central axis;

[0022] the vertical driving mechanism moves the polishing head downward to a set position;

[0023] the horizontal driving mechanism moves the polishing head horizontally to the edge portion of the wafer;

[0024] the vertical driving mechanism continues to move downward, to press the polishing tape against the edge portion of the rotating wafer;

[0025] The horizontal driving mechanism continues to move horizontally to form a ring-shaped opening at the edge portion of the wafer;

[0026] The swing driving mechanism swings the polishing head and the fixing seat, so that the polishing belt on the outer side of the polishing head contacts the corner of the ring-shaped opening;

[0027] The swing driving mechanism swings the polishing head back and forth to eliminate the corner structure of the ring-shaped opening.

[0028] In some embodiments, the swing driving mechanism swings the polishing head back and forth by an angle less than or equal to 30°.

[0029] In some embodiments, when the polishing head processes the ring-shaped opening through the polishing belt, the nozzle sprays deionized water and / or pure gas towards the polishing position to remove the debris generated during processing.

[0030] In some embodiments, when the ring-shaped opening is processed, the polishing belt on the outer side of the polishing head is arranged along the radial direction of the rotating mechanism, so that the process surface of the polishing belt is pressed against the edge portion of the wafer along the radial direction.

[0031] The beneficial effects of the present application include:

[0032] a. The polishing head is combined with the polishing belt, the process surface of the polishing belt directly contacts the forming surface of the ring-shaped opening, thereby obtaining a smooth forming surface, especially ensuring that the side surface of the ring-shaped opening is smooth, effectively avoiding defects such as edge collapse in subsequent processing of the wafer;

[0033] b. The polishing head is provided with a pressing portion, the polishing belt on the outer side is pressed against the edge portion of the wafer, and the ring-shaped opening meeting the process requirements is obtained through vertical feeding and horizontal feeding;

[0034] c. The polishing head is provided with a circular arc portion, so that the corner structure of the ring-shaped opening is eliminated through the back-and-forth swing of the polishing head, further eliminating the stress concentration of the edge of the wafer;

[0035] d. The polishing head is provided with an inclined portion, so that the wound polishing belt is guided towards the outer side of the wafer to at least remove part of the debris generated during polishing, thereby reducing the difficulty of cleaning the edge of the wafer;

[0036] e. The wafer edge polishing device provided can take into account the forming processing of the trim wafer and the edge polishing of the wafer, has the advantage of one machine with multiple functions, and is conducive to controlling the overall cost of wafer processing. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings.

[0038] Figure 1 A schematic view of a wafer edge polishing device provided by an embodiment of the present application;

[0039] Figure 2 A schematic view of a stand plate to which a pay-off reel and a take-up reel are fixed, provided by an embodiment of the present application;

[0040] Figure 3 A top view of a wafer edge polishing device provided by another embodiment of the present application;

[0041] Figure 4 A schematic view of a wafer edge portion formed with an annular opening;

[0042] Figure 5 A schematic view of a polishing head provided by an embodiment of the present application;

[0043] Figure 6 A schematic view of a wafer edge polishing device provided by an embodiment of the present application; Figure 5 A corresponding partial enlarged view of A;

[0044] Figure 7 A flow chart of a wafer edge polishing method provided by the present application;

[0045] Figure 8 A schematic view of a wafer edge polishing preparation process provided by an embodiment of the present application;

[0046] Figure 9 A schematic view of a wafer edge polishing processing process provided by an embodiment of the present application;

[0047] Figure 10 A schematic view of removing the corner structure in the annular opening, provided by an embodiment of the present application;

[0048] Figure 11 A schematic view of reciprocating swing of a polishing head, provided by an embodiment of the present application;

[0049] Figure 12 A schematic view of a trim wafer processed and shaped by the prior art. DETAILED DESCRIPTION

[0050] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art shall fall within the scope of protection of the present application.

[0051] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this application and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0052] It should be understood that although the terms "first", "second", "third" and the like can be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one piece of information from another piece of information. For example, without departing from the scope of the present application, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0053] In the present application, the wafer (Wafer, W) is also referred to as a substrate (Substrate), which has the same meaning and actual role.

[0054] Figure 1 is a schematic view of a wafer edge polishing device 100 provided by an embodiment of the present application, which comprises:

[0055] A rotating mechanism 10 is used to load the wafer W and drive the wafer W to rotate around the central axis.

[0056] A polishing head 20 is used to press the polishing belt 30 against the edge portion of the wafer W, so as to process the edge region of the wafer by the polishing belt 30.

[0057] Furthermore, the rotating mechanism 10 includes a tray 11, with a rotary motor 12 disposed below the tray 11 to drive the tray 11 and the wafer W on it to rotate around a central axis. Since the wafer W is concentrically disposed above the tray 11 of the rotating mechanism 10, it can also be said that the rotating mechanism 10 drives the wafer to rotate around the central axis of the rotating mechanism 10. The tray 11 has grooves / channels inside, which are connected to a vacuum source through pipes to create a negative pressure between the tray 11 and the wafer W, thereby adsorbing the wafer W to be processed onto the surface of the tray 11.

[0058] Figure 1 In the illustrated embodiment, the polishing belt 30 is wound around the bottom of the polishing head 20. Specifically, the polishing belt 30 is a component of the polishing assembly. The polishing belt 30 is led out from the unwinding drum 31, passes through multiple guide rollers 32, and is finally introduced into the take-up drum 33; the unwinding drum 31 and the take-up drum 33 are vertically spaced apart. Figure 2 The side of the upright plate 34 is shown. The unwinding drum 31 is mounted on the output shaft of the unwinding motor 31a, and the take-up drum 33 is mounted on the output shaft of the take-up motor 33a, as shown. Figure 2 As shown, the unwinding motor 31a and the rewinding motor 33a, through torque control, tension and maintain a certain tension force on the polishing belt 30, thereby ensuring a relatively stable material removal rate of the polishing belt 30. It should be noted that the polishing head 20 is also a component of the polishing assembly, and it is equipped with a vertical drive mechanism 40 to change the position of the polishing head 20. Specifically, the polishing head 20 is positioned below the vertical drive mechanism 40 to drive the polishing head 20 to move along the length of the output shaft of the vertical drive mechanism 40, thereby moving it closer to or further away from the wafer W to be polished.

[0059] Figure 1 In this design, a vertical drive mechanism 40 is mounted on a fixed base 50, which is located to the side of the rotating mechanism 10 to provide sufficient space for wafer loading and unloading. Simultaneously, a guide wheel 32 is also mounted on the fixed base 50 to guide the polishing belt 30. It is understood that the fixed base 50 can be positioned above and / or below the tray 11 of the rotating mechanism 10, so that the vertical drive mechanism 40 can drive the polishing head 20 closer to the edge of the wafer W, thereby processing the edge of the wafer through the polishing belt 30 to form a trim wafer.

[0060] In some embodiments, the vertical drive mechanism 40 can be a linear motion module such as a cylinder or a servo motor to drive the polishing head 20 to move in a linear direction.

[0061] Furthermore, the polishing assembly also includes a horizontal drive mechanism 60, which is connected to the vertical drive mechanism 40 via a bracket 70 to drive the fixed base 50 and the polishing head 20 thereon to move horizontally toward or away from the edge of the wafer.

[0062] The horizontal driving mechanism 60 can be a linear moving module, and the moving block thereof moves along the slide rail to change the horizontal position of the polishing head 20. Since the horizontal moving distance of the polishing head 20 is short, the horizontal moving distance thereof is usually the distance of the processing feed, and the polishing belt 30 is adaptively elongated under the condition of maintaining a certain tension during the movement of the polishing head 20 driven by the horizontal driving mechanism 60.

[0063] Figure 3 FIG. 10 is a top view of a wafer edge polishing device 100 according to another embodiment of the present application, wherein the wafer edge polishing device 100 is provided with four polishing assemblies, and the four polishing assemblies are dispersedly arranged outside the wafer W to be processed to process the edge portion of the wafer by the polishing belt 30.

[0064] In the present application, the wafer edge polishing device 100 further comprises a swing driving mechanism 80 Figure 3 which is connected to the side of the fixed seat 50 to drive the fixed seat 50 and the polishing head 20 thereon to swing, thereby changing the contact state between the polishing head 20 and the edge portion of the wafer W.

[0065] Figure 4 In the embodiment shown, the swing driving mechanism 80 is a swing motor, and the output shaft thereof is connected to the fixed seat 50 to drive the fixed seat 50 and the polishing head 20 to synchronously swing. It can be understood that the swing driving mechanism 80 can also realize the swing of the polishing head 20 through a cam mechanism, a crank rocker mechanism, etc. to adapt to different working conditions, which will not be described herein.

[0066] In some embodiments, the polishing head 20 moves in the horizontal direction and / or swings around a fixed point to form a ring-shaped opening Figure 4 in the edge of the wafer W, thereby reducing or eliminating the stress concentration of the wafer edge, preventing the fragmentation of the wafer edge region in the subsequent process such as wafer bonding, and thereby improving the quality of wafer processing.

[0067] In the present application, when the ring-shaped opening is processed, the polishing belt 30 outside the polishing head 20 is arranged in the radial direction of the rotating mechanism 10; specifically, the polishing belt 30 is arranged in the radial direction of the tray 11 of the rotating mechanism 10. Since the wafer W to be processed is concentrically arranged above the tray 11, the polishing belt 30 is arranged in the radial direction of the wafer W, so that the process surface of the polishing belt 30 is pressed against the edge portion of the wafer W in the radial direction. Here, the process surface of the polishing belt 30 refers to the surface attached with abrasive grains, i.e. the outer side surface of the polishing belt 30 in contact with the edge portion of the wafer W. The abrasive grains of the polishing belt 30 can be of different sizes, and the polishing belt with larger abrasive grains is usually used for rough polishing of the wafer, and has a higher material removal rate to realize rapid polishing; and the polishing belt with smaller abrasive grains is usually used for fine polishing to control the roughness of the wafer surface and obtain a clean surface meeting the process requirements.

[0068] With this configuration, the polishing head 20 and polishing belt 30 are combined, and the process surface of the polishing belt 30 directly contacts the forming surface of the annular opening, thereby obtaining a smooth forming surface, especially ensuring that the sides of the annular opening are smooth, in order to solve... Figure 12 The technical problem shown is to prevent unevenness on the sides of the formed annular opening, thereby effectively avoiding defects such as edge chipping during subsequent wafer processing.

[0069] Figure 5 This is a schematic diagram of a polishing head 20 provided in an embodiment of the present invention. At least a portion of the polishing head 20 has a non-planar structure to remove the sharp edges of the annular opening formed at the edge of the wafer, further eliminate stress concentration, and prevent the wafer from cracking or breaking at the sharp edges during subsequent processing and transport.

[0070] Furthermore, the polishing head 20 includes an inclined portion 21, such as... Figure 6 As shown, the inclined portion 21 extends upward from the bottom surface of the polishing head 20, and the inclined portion 21 is away from the central axis of the rotating mechanism 10, so that the wound polishing belt 30 is guided towards the outside of the wafer. During the processing, the polishing belt 30 can at least remove some of the debris generated during polishing, thereby reducing the difficulty of cleaning the wafer edge.

[0071] It is understandable that when installing the polishing head 20, the inclined portion 21 needs to be installed away from the wafer to be processed, so that the polishing belt 30 is guided outward through the inclined portion 21 at the bottom of the polishing head 20, and the debris generated by polishing moves towards the outside of the wafer, thus avoiding the debris from adhering to the wafer surface.

[0072] In some embodiments, the angle between the inclined portion 21 and the horizontal plane is 15-70°, so as to guide the polishing belt 30 upward and outward.

[0073] The angle between the inclined portion 21 and the horizontal plane is designed not only to facilitate the discharge of polishing debris but also to consider the placement of the guide wheels 32. This ensures a balanced mass distribution among the components on the fixed base 50, thereby guaranteeing the stability of the fixed base 50 as it oscillates around a fixed point. Preferably, the angle between the inclined portion 21 and the horizontal plane is 30-45° to optimize the distribution of the guide wheels 32 and ensure efficient discharge of polishing debris.

[0074] Figure 6 In the polishing head 20, there is an arc-shaped portion 22, which is disposed opposite to the inclined portion 21 to eliminate the angular structure of the annular opening.

[0075] Further, the circular arc radius of the circular arc portion 22 is R3-R10, so that the polishing belt 30 coated outside the circular arc portion 22 has a certain arc, and the polishing belt 30 can grind the corners on the annular opening, especially the corners at the right angle edges of the annular opening, to eliminate the potential stress concentration of the annular opening and ensure the quality of wafer processing.

[0076] In the present application, the polishing head 20 further comprises a pressing portion 23, which is located on the bottom surface of the polishing head 20, and the pressing portion 23 is located between the inclined portion 21 and the circular arc portion 22, so that the polishing belt 30 can press downward, and the pressing portion 23 can feed the edge portion of the wafer vertically to realize material removal.

[0077] In order to prevent the shape of the junction between the pressing portion 23 and the inclined portion 21 from affecting the polishing belt 30, reduce the wear rate of the polishing belt 30, and maintain a certain tension, the junction between the pressing portion 23 and the inclined portion 21 adopts a circular arc transition. Preferably, the circular arc radius of the junction between the pressing portion 23 and the inclined portion 21 is less than 5 mm.

[0078] Further, the horizontal width of the pressing portion 23 is directly related to the processing speed of the polishing head 20, and the horizontal width of the pressing portion 23 is usually less than or equal to the horizontal width of the annular opening. Specifically, the horizontal width of the pressing portion 23 is 1-6 mm.

[0079] The horizontal width of the pressing portion 23 is related to the discharge efficiency of the polishing debris in addition to the processing speed of the polishing head 20. Preferably, the horizontal width of the pressing portion 23 is 60%-80% of the horizontal width of the annular opening, so that the polishing head 20 can be appropriately moved towards the center direction of the wafer W during the forming of the annular opening, so that the polishing debris can be discharged through the gap between the wafer forming surface and the polishing belt 30.

[0080] It should be noted that the wafer edge polishing device 100 provided by the present application can be used not only for processing trim wafers, but also for polishing the edges of wafers (edge polishing), which has the advantages of one machine with multiple functions and is conducive to controlling the overall cost of wafer processing. When polishing the edges of wafers, only the appropriate polishing head needs to be replaced and the corresponding feeding sequence needs to be adjusted.

[0081] In addition, the present application also provides a wafer edge polishing method, which uses the wafer edge polishing device 100 provided by the present application. Figure 1 The wafer edge polishing device 100 is shown, and the flow chart of the wafer edge polishing method is shown as follows. Figure 7 The wafer edge polishing method comprises the following steps:

[0082] S1, the rotating mechanism 10 loads the wafer W and drives the wafer W to rotate around the center axis;

[0083] Specifically, the wafer W is placed on the tray 11 and held by vacuum suction by the external robot, and the rotation motor 12 at the lower part of the tray 11 drives the tray 11 and the wafer W thereon to rotate synchronously.

[0084] S2, the vertical driving mechanism moves the polishing head downward to a set position;

[0085] Specifically, the output shaft of the vertical driving mechanism 40 moves the polishing head 20 downward (vertical feed), as shown in Figure 8 (a), a certain distance is reserved between the bottom surface of the polishing head 20 and the surface of the wafer W, which can be 5-10 mm, so as to further feed the polishing head 20 downward when processing the annular opening.

[0086] S3, the horizontal driving mechanism 60 moves the polishing head 20 horizontally to the edge part of the wafer;

[0087] Specifically, the horizontal driving mechanism 60 moves the polishing head 20 on the fixing seat 50 along the horizontal direction (lateral feed) through the support 70 and the fixing seat 50, so as to move the polishing head 20 to the edge part of the wafer, as shown in Figure 8 (b).

[0088] It should be noted that the steps S2 and S3 have no existing order, the polishing head 20 can be moved horizontally first and then vertically, or the polishing head 20 can be moved horizontally and vertically at the same time; as long as the polishing head 20 moves to the position to be processed.

[0089] S4, the vertical driving mechanism 40 continues to move downward to press the polishing belt 30 against the edge part of the rotating wafer;

[0090] Specifically, the vertical driving mechanism 40 drives the polishing head 20 to move towards the wafer W, as shown in Figure 9 (a), so that the polishing belt 30 abuts against the edge part of the wafer W. When the polishing head 20 moves to the process depth, the downward movement is stopped, so as to form the annular opening meeting the process requirements.

[0091] S5, the horizontal driving mechanism 60 continues to move horizontally to form the annular opening at the edge part of the wafer W;

[0092] Specifically, the horizontal driving mechanism 60 drives the fixing seat 50 and the polishing head 20 thereon to move horizontally through the support 70, as shown in Figure 9 (b), so as to form the annular opening meeting the process requirements at the edge of the wafer W.

[0093] S6, the swing driving mechanism 80 swings the fixing seat 50 and the polishing head 20 thereon, so that the polishing belt 30 outside the polishing head 20 contacts the corner of the annular opening;

[0094] Specifically, the output shaft of the swing driving mechanism 80 drives the fixed seat 50 to swing, so that the polishing head fixed on the fixed seat 50 swings, and then the polishing belt 30 outside the polishing head 20 contacts the edges of the annular opening, as shown in Figure 10 (a) to further process the edges of the annular opening through the polishing belt 30.

[0095] S7, the swing driving mechanism 80 reciprocatingly swings the polishing head 20 to eliminate the edge structure of the annular opening.

[0096] Specifically, the swing driving mechanism 80 reciprocatingly swings the polishing head 20, as shown in Figure 10 (b), the swing angle of the polishing head 20 is less than or equal to 30°, so as to increase the contact area between the polishing belt 30 and the edge structure and accelerate the grinding of the edge structure.

[0097] Figure 11 is a schematic view of the polishing head 20 swinging a certain angle under the driving of the swing driving mechanism 80, so that the polishing belt 30 outside the polishing head 20 can contact the edge structure of the annular opening, and then eliminate the sharp corners of the annular opening, avoiding the defects such as cracking and edge collapse of the wafer in subsequent processing.

[0098] It should be noted that the swing amplitude of the polishing head 20 is related to the size of the circular arc structure formed at the edge of the annular opening, the size of the abrasive grains of the polishing belt 30, and the size of the circular arc part 22 of the polishing head 20, and the swing amplitude of the polishing head 20 needs to be determined by comprehensively balancing the above-mentioned influencing factors.

[0099] In the wafer edge polishing process, the polishing head 20 is combined with the polishing belt 30, and the process surface of the polishing belt 30 directly contacts the forming surface of the annular opening, instead of the side surface of the polishing belt or the grinding wheel contacting the side surface of the annular opening to be formed in the prior art, so as to obtain a smooth forming surface, especially to ensure the smoothness of the side surface of the annular opening, avoid the unevenness of the side surface, and effectively avoid the defects such as cracking and edge collapse in the subsequent processing of the wafer.

[0100] In the present application, when the polishing head 20 processes the annular opening through the polishing belt 30, the nozzle 90 (shown in Figure 1 sprays deionized water and / or pure gas towards the polishing position to remove the debris generated in the processing.

[0101] Specifically, a large amount of polishing debris is generated during the wafer edge processing; in order to ensure the cleanliness of the wafer edge polishing process and reduce the difficulty of subsequent cleaning, the nozzle 90 is usually arranged outside the polishing head 20 to spray fluid with a certain pressure and flow rate towards the polishing position during the process of the polishing belt 30 grinding the edge part of the wafer W, so as to remove the debris generated in the polishing.

[0102] In some embodiments, the nozzle 90 needs to spray deionized water to flush away the particles adhered to the wafer surface; in some embodiments, the nozzle 90 needs to spray pure gas to blow away the particles on the wafer surface; in some working conditions, the nozzle 90 needs to spray a mixture of deionized water and pure gas, both mixed in a certain proportion.

[0103] The deionized water can take away the soluble dirt and residual small particle impurities on the surface by its fluidity and solubility; the pure gas can generate impact force when sprayed at high speed to blow off some loosely adhered contaminants, and can also be used to blow dry the wafer surface after cleaning to avoid the problem of incomplete cleaning caused by water stains; the gas-liquid mixture combines the advantages of both, the disturbance of the gas can make the liquid penetrate better into some hard-to-reach gaps and corners, enhancing the cleaning effect, and the gas-liquid mixture, because of the addition of gas, improves the cleaning effect while reducing the proportion of deionized water used, which is conducive to controlling the wafer processing cost.

[0104] In the present application, the feed speed of the polishing belt 30 is 10-20 mm / min, so as to control the excessive outward escape of polishing debris under the condition of ensuring the polishing rate of the wafer edge, make the flow field inside the wafer edge polishing device relatively stable, and inhibit the influence of the polishing debris on the wafer processing effect.

[0105] Those skilled in the art can appreciate that the units and method steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present application.

[0106] The above implementation manners are only used to illustrate the embodiments of the present application, and not to limit the embodiments of the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application, therefore all equivalent technical solutions also belong to the scope of the embodiments of the present application, the patent protection scope of the embodiments of the present application should be defined by the claims.

Claims

1. A wafer edge polishing apparatus, characterized in that, include: A rotating mechanism is used to load the wafer and drive it to rotate around a central axis. A polishing assembly, comprising a polishing head and a polishing belt, wherein the polishing head presses the polishing belt against the edge of a wafer; The polishing head moves horizontally and / or oscillates around a fixed point to form an annular opening at the edge of the wafer; at least a portion of the polishing head has a non-planar structure, such that the formed annular opening has no sharp edges. The polishing head includes an inclined portion and an arc portion. The inclined portion extends upward from the bottom surface of the polishing head and away from the central axis of the rotating mechanism to guide the polishing belt upward and outward. The arc portion is arranged opposite to the inclined portion to eliminate the angular structure of the annular opening. It also includes a swing drive mechanism, which is a swing motor used to drive the polishing head to swing, thereby changing the contact state between the polishing head and the edge of the wafer.

2. The wafer edge polishing apparatus according to claim 1, characterized in that, The polishing head is equipped with a vertical drive mechanism, which is a linear movement module, to drive the polishing head to move along the length direction of the output shaft of the vertical drive mechanism; the vertical drive mechanism is set on a fixed base, and the fixed base is located to the side of the rotating mechanism.

3. The wafer edge polishing apparatus according to claim 2, characterized in that, The vertical drive mechanism is connected to the horizontal drive mechanism via a bracket. The horizontal drive mechanism is a linear motion module, on which a moving block moves along a slide rail to drive the fixed base and the polishing head on it to move horizontally, thereby moving closer to or away from the edge of the wafer.

4. The wafer edge polishing apparatus according to claim 3, characterized in that, The output shaft of the swing drive mechanism is connected to the fixed base to drive the fixed base and the polishing head on it to swing.

5. The wafer edge polishing apparatus according to claim 1, characterized in that, The polishing belt is led out by the unwinding drum and introduced into the take-up drum via multiple guide wheels; the unwinding drum and the take-up drum are arranged vertically at intervals on the side of the upright plate.

6. The wafer edge polishing apparatus according to claim 5, characterized in that, The unwinding drum is mounted on the output shaft of the unwinding motor, and the winding drum is mounted on the output shaft of the winding motor. The unwinding motor and the winding motor are controlled by torque to maintain the tension of the polishing belt.

7. The wafer edge polishing apparatus according to claim 2, characterized in that, The mounting base is located on the upper and / or lower side of the tray of the rotating mechanism to drive the polishing head closer to or away from the edge of the wafer via the vertical drive mechanism.

8. The wafer edge polishing apparatus according to claim 1, characterized in that, The number of polishing components is four, which are distributed on the outer side of the wafer to be processed to process the edge of the wafer through the polishing belt.

9. The wafer edge polishing apparatus according to claim 1, characterized in that, The polishing head also includes a pressing section disposed between the inclined section and the arc section, which presses downward through the polishing belt and then feeds the edge of the wafer vertically; the junction of the pressing section and the inclined section adopts an arc transition.

10. The wafer edge polishing apparatus according to claim 9, characterized in that, The radius of the arc at the junction of the extrusion section and the inclined section is less than 5 mm.

11. The wafer edge polishing apparatus according to claim 9, characterized in that, The horizontal width of the extrusion section is less than or equal to the horizontal width of the annular opening.

12. The wafer edge polishing apparatus according to claim 11, characterized in that, The horizontal width of the extrusion section is 60%-80% of the horizontal width of the annular opening.

13. A method for polishing wafer edges, characterized in that, Using the wafer edge polishing apparatus according to any one of claims 1-12, comprising: The rotating mechanism loads the wafer and drives it to rotate around the central axis; The vertical drive mechanism moves the polishing head downwards to the set position; The horizontal drive mechanism moves the polishing head horizontally to the edge of the wafer; The vertical drive mechanism continues to move downwards to press against the edge of the rotating wafer via the polishing belt; The horizontal drive mechanism continues to move horizontally to form an annular opening at the edge of the wafer; The swing drive mechanism swings the fixed base and the polishing head on it, so that the polishing strip on the outside of the polishing head contacts the edge of the annular opening. The oscillating drive mechanism drives the polishing head to oscillate back and forth to eliminate the angular structure of the annular opening.

14. The wafer edge polishing method according to claim 13, characterized in that, During the wafer edge polishing process, the polishing head is combined with the polishing belt, and the process surface of the polishing belt is in direct contact with the forming surface of the annular opening; the process surface is a surface with abrasive particles attached.

15. The wafer edge polishing method according to claim 13, characterized in that, The vertical drive mechanism moves the polishing head downwards to a set position, and the reserved distance between the bottom surface of the polishing head and the surface of the wafer is 5-10mm.

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