Wafer edge polishing method and polishing device

Abstract

The invention discloses a wafer edge polishing method and device, and the device comprises a rotating mechanism which is used for loading a wafer and driving the wafer to rotate around a central axis; a polishing head that presses the polishing tape against the edge portion of the wafer; the polishing head moves in the horizontal direction and / or swings around a fixed point so as to form an annular opening in the edge of the wafer; and at least part of the polishing head is of a non-planar structure, so that the formed annular opening has no corner angle structure.

Description

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

[0002] The embodiments of the present application relate to the field of semiconductor manufacturing technology, and in particular to a wafer edge polishing method and a polishing device. Background Art

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

[0004] Wafer trimming can use a grinding wheel to abut the edge of the wafer, such as the technical solution disclosed in patent CN111403315A, so as to process the edge of the wafer into a shape and size that meets the process requirements; wafer trimming 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 at the edge of the wafer.

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

[0006] During wafer trimming, the side of the grinding wheel or polishing belt is in direct contact with the side of the formed step structure, and the side of the grinding wheel or polishing belt is a non-processing surface, which will affect the forming quality of the side of the step structure, and the side of the step structure will appear uneven, such as Fig.12 In the subsequent wafer bonding process, debris will fall off the side of the step structure, thus affecting the wafer bonding effect.

[0007] In addition, the side of the step structure is uneven, which is easy to attach a small amount of particles. Due to the large roughness of the side, this will increase the adhesion strength of the particles, thereby increasing the difficulty of cleaning the edge of the trim wafer. Summary of the invention

[0008] In view of this, an embodiment of the present application provides a wafer edge polishing method and a polishing device to at least partially solve the above-mentioned problems.

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

[0010] A rotating mechanism, used to load the wafer and drive the wafer to rotate around the central axis;

[0011] A polishing head, which presses the polishing tape against the edge of the wafer;

[0012] The polishing head moves in a horizontal direction and / or swings around a fixed point to form an annular opening at the edge of the wafer; at least a portion of the polishing head is a non-planar structure, so that the formed annular opening has no angular structure;

[0013] 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.

[0014] In some embodiments, the polishing head is equipped with a vertical driving mechanism to drive the polishing head to move along the length direction of the output shaft of the vertical driving mechanism; the vertical driving mechanism is disposed on a fixed seat, and the fixed seat is disposed on the side of the rotating mechanism.

[0015] In some embodiments, the vertical driving mechanism is connected to the horizontal driving mechanism through a bracket, and the horizontal driving mechanism drives the fixed seat and the polishing head thereon to move horizontally to approach or move away from the edge of the wafer.

[0016] In some embodiments, the wafer edge polishing device further includes a swing drive mechanism connected to the fixed seat to drive the fixed seat and the polishing head thereon to swing so as to change the contact state between the polishing head and the edge of the wafer.

[0017] In some embodiments, the polishing head further includes a pressing portion, which is disposed between the inclined portion and the arc portion, so as to press downward through the polishing belt, thereby vertically feeding the edge of the processed wafer.

[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 extruded portion is 1-6 mm.

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

[0021] The rotating mechanism loads the wafer and drives the wafer to rotate 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 of the wafer;

[0024] The vertical driving mechanism continues to move downward to press against the edge of the rotating wafer through the polishing belt;

[0025] The horizontal driving mechanism continues to move horizontally to form an annular opening at the edge of the wafer;

[0026] The swing driving mechanism swings the fixed seat and the polishing head thereon, so that the polishing belt outside the polishing head contacts the edges and corners of the annular opening;

[0027] The swing driving mechanism drives the polishing head to swing back and forth to eliminate the angular structure of the annular opening.

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

[0029] In some embodiments, when the polishing head processes the annular opening through the polishing belt, the nozzle sprays deionized water and / or pure gas toward the polishing position to remove debris generated by the processing.

[0030] In some embodiments, during the annular opening processing, 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 of the wafer along the radial direction.

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

[0032] a. 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, thereby obtaining a smooth forming surface, especially ensuring that the side of the annular opening is smooth, effectively avoiding defects such as edge collapse in subsequent wafer processing;

[0033] b. The polishing head is equipped with an extrusion part, and the outer polishing belt is pressed against the edge of the wafer. Through vertical feeding and horizontal feeding, a circular opening that meets the process requirements is obtained;

[0034] c. The polishing head is equipped with an arc portion, so that the angular structure of the annular opening can be eliminated through the reciprocating swing of the polishing head, and the stress concentration at the edge of the wafer can be further eliminated;

[0035] d. The polishing head is provided with an inclined portion so that the wound polishing tape is guided toward the outside of the wafer to at least take away some of the debris generated by polishing, thereby reducing the difficulty of cleaning the edge of the wafer;

[0036] e. The wafer edge polishing device provided can take into account both the trim wafer forming process and the wafer edge polishing (edge ​​polishing), and has the advantage of one machine with multiple uses, which is beneficial to controlling the comprehensive cost of wafer processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0038] Figure 1 A schematic diagram of a wafer edge polishing device provided in one embodiment of the present application;

[0039] Figure 2 A schematic diagram of an unwinding drum and a winding drum provided in an embodiment of the present application being fixed to a vertical plate;

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

[0041] Figure 4 A schematic diagram showing a circular opening formed at the edge of a wafer;

[0042] Figure 5 A schematic diagram of a polishing head provided in one embodiment of the present application;

[0043] Figure 6 for Figure 5 The corresponding partial enlarged image of point A;

[0044] Figure 7 A flow chart of a wafer edge polishing method provided for this application;

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

[0046] Fig. 9 A schematic diagram of a wafer edge polishing process provided in an embodiment of the present application;

[0047] Fig.10 A schematic diagram of removing the angular structure in the annular opening provided in an embodiment of the present application;

[0048] Fig.11 A schematic diagram of the reciprocating swing of the polishing head provided in an embodiment of the present application;

[0049] Fig.12 A schematic diagram of a trim wafer formed by conventional technology. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0051] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0052] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0053] In the present invention, wafer (Wafer, W) is also called substrate (Substrate), and its meaning and actual function are equivalent.

[0054] Figure 1 is a schematic diagram of a wafer edge polishing device 100 provided in one embodiment of the present application. The wafer edge polishing device 100 includes:

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

[0056] The polishing head 20 presses the polishing tape 30 against the edge of the wafer W so as to process the edge region of the wafer through the polishing tape 30 .

[0057] Furthermore, the rotating mechanism 10 includes a tray 11, and a rotating motor 12 is arranged below the tray 11 to drive the tray 11 and the wafer W thereon to rotate around the central axis. Since the wafer W is concentrically arranged 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. A groove / channel is arranged inside the tray 11, and the groove / channel is connected to a vacuum source through a pipeline to form a negative pressure between the tray 11 and the wafer W, thereby adsorbing the wafer W to be processed on the surface of the tray 11.

[0058] Figure 1 In the embodiment shown, the polishing tape 30 is wound around the bottom of the polishing head 20. Specifically, the polishing tape 30 is a component of the polishing assembly. The polishing tape 30 is drawn out from a reel 31, passes through a plurality of guide wheels 32, and is finally introduced into a reel 33. The reel 31 and the reel 33 are arranged vertically at intervals. Figure 2 The side of the vertical plate 34 is shown. The unwinding drum 31 is installed on the output shaft of the unwinding motor 31a, and the winding drum 33 is installed on the output shaft of the winding motor 33a. Figure 2 As shown, the unwinding motor 31a and the winding motor 33a control the torque to tighten the polishing belt 30 and maintain a certain tension, thereby ensuring that the material removal rate of the polishing belt 30 is relatively stable. It should be noted that the polishing head 20 is also a component of the polishing assembly, which is equipped with a vertical driving mechanism 40 to change the position of the polishing head 20. Specifically, the polishing head 20 is arranged below the vertical driving mechanism 40 to drive the polishing head 20 to move along the length direction of the output shaft of the vertical driving mechanism 40 to approach or move away from the wafer W to be polished.

[0059] Figure 1 In the embodiment, the vertical driving mechanism 40 is disposed on the fixing seat 50, and the fixing seat 50 is disposed on the side of the rotating mechanism 10 to provide sufficient space for the wafer to be taken and placed; meanwhile, the guide wheel 32 is also disposed on the fixing seat 50 to guide the direction of the polishing belt 30. It is understood that the fixing seat 50 can be disposed on the upper side and / or the lower side of the tray 11 of the rotating mechanism 10, so as to drive the polishing head 20 to approach the edge of the wafer W through the vertical driving mechanism 40, and then process the edge of the wafer through the polishing belt 30 to form a trim wafer.

[0060] In some embodiments, the vertical driving mechanism 40 may 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 driving mechanism 60, which is connected to the vertical driving mechanism 40 through a bracket 70 to drive the fixed seat 50 and the polishing head 20 thereon to move in a horizontal direction to approach or move away from the edge of the wafer.

[0062] The horizontal driving mechanism 60 may be a linear moving module, and the moving block on the horizontal driving mechanism 60 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, which is usually the distance of processing feed, the polishing belt 30 adaptively extends under the condition of maintaining a certain tension when the horizontal driving mechanism 60 drives the polishing head 20 to move.

[0063] Figure 3 It is a top view of a wafer edge polishing device 100 provided in another embodiment of the present invention. In this embodiment, the wafer edge polishing device 100 is configured with four polishing components, and the four polishing components are dispersedly arranged on the outside of the wafer W to be processed so as to process the edge of the wafer through the polishing belt 30.

[0064] In the present invention, the wafer edge polishing device 100 further includes a swing drive mechanism 80 ( Figure 3 ), which is connected to the side of the fixing base 50 to drive the fixing base 50 and the polishing head 20 thereon to swing, thereby changing the contact state between the polishing head 20 and the edge of the wafer W.

[0065] Figure 4 In the illustrated embodiment, the swing drive mechanism 80 is a swing motor, whose output shaft is connected to the fixed seat 50 to drive the fixed seat 50 and the polishing head 20 to swing synchronously. It is understandable that the swing drive 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 repeated here.

[0066] In some embodiments, the polishing head 20 moves in a horizontal direction and / or swings around a fixed point to form an annular opening ( Figure 4 As shown), the stress concentration at the edge of the wafer is reduced or eliminated, so that during subsequent processes such as wafer bonding, the chipping of the edge area of ​​the wafer is prevented, thereby improving the quality of wafer processing.

[0067] In the present invention, during the processing of the annular opening, the polishing belt 30 on the outside of the polishing head 20 is arranged along the radial direction of the rotating mechanism 10; specifically, the polishing belt 30 is arranged along 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 along the radial direction of the wafer W, so that the process surface of the polishing belt 30 is radially pressed against the edge of the wafer W. Here, the process surface of the polishing belt 30 refers to the surface with abrasive grains attached, that is, the outer side surface of the polishing belt 30 in contact with the edge of the wafer W. The abrasive grains of the polishing belt 30 can be different in size. The polishing belt with larger abrasive grains is usually used for rough polishing of the wafer, and its material removal rate is higher to achieve rapid polishing; the polishing belt with smaller abrasive grains is usually used for fine polishing, so as to control the roughness of the wafer surface and obtain a clean surface that meets the process requirements.

[0068] In this way, the polishing head 20 is combined with the polishing belt 30, and the process surface of the polishing belt 30 is in direct contact with the forming surface of the annular opening, thereby obtaining a smooth forming surface, especially ensuring that the side surface of the annular opening is smooth, so as to solve the problem of Fig.12 The technical problem shown can prevent the side of the formed annular opening from becoming uneven, thereby effectively avoiding defects such as edge collapse in subsequent processing of the wafer.

[0069] Figure 5 It is a schematic diagram of a polishing head 20 provided in one embodiment of the present invention. At least a portion of the polishing head 20 is a non-planar structure to remove the edges and corners of the annular opening formed at the edge of the wafer, further eliminate stress concentration, and avoid cracks or breakage of the wafer from the edges and corners during subsequent processing and transmission.

[0070] Further, 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 tape 30 is guided toward the outside of the wafer. During the processing, the polishing tape 30 can at least take away some of the debris generated by polishing, thereby reducing the difficulty of cleaning the edge of the wafer.

[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 toward the outside through the inclined portion 21 at the bottom of the polishing head 20, and the debris generated by polishing moves toward the outside of the wafer to prevent 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 degrees, so as to guide the polishing belt 30 obliquely upward and outward.

[0073] The angle between the inclined portion 21 and the horizontal plane should not only take into account the discharge of polishing debris, but also the location of the guide wheel 32, so as to balance the mass distribution of each component on the fixed seat 50, thereby ensuring the stability of the reciprocating swing of the fixed seat 50 around the fixed point. Preferably, the angle between the inclined portion 21 and the horizontal plane is 30-45°, so as to reasonably arrange the distribution of the guide wheel 32 and ensure the efficient discharge of polishing debris.

[0074] Figure 6 In the embodiment, the polishing head 20 includes a circular arc portion 22, and the circular arc portion 22 is arranged opposite to the inclined portion 21 to eliminate the angular structure of the annular opening.

[0075] Furthermore, the arc radius of the arc portion 22 is R3-R10, so that the polishing belt 30 wrapped around the outside of the arc portion 22 has a certain curvature, and thus the polishing belt 30 can grind the edges and corners on the annular opening, especially the edges and corners at the right angles of the annular opening, so as to eliminate the potential stress concentration of the formed annular opening and ensure the quality of wafer processing.

[0076] In the present invention, the polishing head 20 also includes an extrusion portion 23, which is located on the bottom surface of the polishing head 20, and the extrusion portion 23 is located between the inclined portion 21 and the arc portion 22, so as to be pressed downward by the polishing belt 30. The extrusion portion 23 can vertically feed the edge of the processed wafer to achieve material removal.

[0077] In order to prevent the shape of the junction between the extrusion part 23 and the inclined part 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 extrusion part 23 and the inclined part 21 adopts an arc transition. Preferably, the arc radius of the junction between the extrusion part 23 and the inclined part 21 is less than 5 mm.

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

[0079] The horizontal width of the pressing portion 23 is related to the processing speed of the polishing head 20 and the discharge efficiency of the polishing debris. Preferably, the horizontal width of the pressing portion 23 is 60%-80% of the horizontal width of the annular opening, so that during the forming process of the annular opening, the polishing head 20 is appropriately moved toward the center direction of the wafer W, 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 invention can not only be used for trimming wafers, but also for edge polishing of wafers, and has the advantage of one machine for multiple uses, which is beneficial to controlling the comprehensive cost of wafer processing. When performing wafer edge polishing, it is only necessary to replace a suitable polishing head and adaptively adjust the corresponding feeding sequence.

[0081] In addition, the present invention also provides a wafer edge polishing method, which uses Figure 1 The wafer edge polishing apparatus 100 and the flow chart of the wafer edge polishing method are shown as follows. Figure 7 As shown, it includes:

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

[0083] Specifically, an external robot places the wafer W on the tray 11 and holds it by vacuum adsorption, and a rotary motor 12 at the bottom of the tray 11 drives the tray 11 and the wafer W thereon to rotate synchronously.

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

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

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

[0087] Specifically, the horizontal driving mechanism 60 moves the polishing head 20 on the fixed seat 50 in the horizontal direction (lateral feeding) through the bracket 70 and the fixed seat 50, so that the polishing head 20 moves to the edge of the wafer, such as Figure 8 (b) as shown.

[0088] It should be noted that there is no existing order for steps S2 and S3. The polishing head 20 can move horizontally first and then vertically, or the polishing head 20 can move 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 against the edge of the rotating wafer through the polishing belt 30;

[0090] Specifically, the vertical drive mechanism 40 drives the polishing head 20 to move toward the wafer W, such as Fig. 9 As shown in (a), the polishing belt 30 is in contact with the edge of the wafer W. When the polishing head 20 moves to the process depth, it stops moving downward to form an annular opening that meets the process requirements.

[0091] S5, the horizontal driving mechanism 60 continues to move horizontally to form a ring-shaped opening at the edge 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 bracket 70. Fig. 9 As shown in (b), a ring-shaped opening that meets the process requirements is formed at the edge of the wafer W.

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

[0094] Specifically, the output shaft of the swing drive 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 corners of the annular opening, such as Fig.10 As shown in (a), the edges and corners of the annular opening are further processed by a polishing belt 30.

[0095] S7, the swing driving mechanism 80 drives the polishing head 20 to swing back and forth to eliminate the angular structure of the annular opening.

[0096] Specifically, the swing drive mechanism 80 drives the polishing head 20 to swing back and forth. Fig.10 As shown in (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 angular structure and accelerate the grinding of the angular structure.

[0097] Fig.11 It is a schematic diagram of the polishing head 20 swinging at a certain angle driven by the swing driving mechanism 80, so that the polishing belt 30 on the outside of the polishing head 20 can contact the angular structure of the annular opening, thereby eliminating the sharp corners of the annular opening and avoiding defects such as chipping and edge collapse of the wafer during subsequent processing.

[0098] It should be noted that the amplitude of the reciprocating swing of the polishing head 20 is related to the size of the arc structure formed at the corners of the annular opening, the abrasive size of the polishing belt 30 and the size of the arc portion 22 of the polishing head 20. It is necessary to comprehensively weigh the influencing factors mentioned above to determine the swing amplitude of the polishing head 20.

[0099] During 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 is in direct contact with the forming surface of the annular opening, rather than the side of the grinding wheel or the polishing belt in the prior art contacting the side of the annular opening to be formed, thereby obtaining a smooth forming surface, especially ensuring the smoothness of the side of the annular opening, avoiding unevenness on the side, and effectively avoiding defects such as chipping and edge collapse in subsequent processing of the wafer.

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

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

[0102] In some embodiments, the nozzle 90 needs to spray deionized water to rinse and remove particles attached to the wafer surface; in some embodiments, the nozzle 90 needs to spray pure gas to blow away particles on the wafer surface; under some working conditions, the nozzle 90 needs to spray a mixture of deionized water and pure gas, which are mixed in a certain proportion.

[0103] Deionized water can remove soluble dirt and residual tiny particles of impurities on the surface by virtue of its fluidity and solubility; pure gas can generate impact force when sprayed at high speed, blowing off some loosely attached pollutants. It can also be used to dry the wafer surface after cleaning to avoid incomplete cleaning caused by residual water stains; the gas-liquid mixture combines the advantages of both. The disturbance of the gas can make the liquid better penetrate into some hard-to-reach gaps and corners, enhancing the cleaning effect. In addition, the gas-liquid mixture improves the cleaning effect while reducing the proportion of deionized water used due to the addition of gas, which is beneficial to control wafer processing costs.

[0104] In the present invention, the feed speed of the polishing belt 30 is 10-20 mm / min, so as to control the excessive outward escape of polishing debris while ensuring the wafer edge polishing rate, so that the flow field inside the wafer edge polishing device is relatively stable, thereby suppressing the influence of polishing debris on the wafer processing effect.

[0105] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0106] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field 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 scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A wafer edge polishing device, characterized in that: include: A rotating mechanism, used to load the wafer and drive the wafer to rotate around the 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 the wafer; The polishing head moves in a horizontal direction and / or swings around a fixed point to form an annular opening at the edge of the wafer; at least a portion of the polishing head is a non-planar structure, so that the formed annular opening has no angular structure; The polishing head comprises an inclined portion and an arc portion, wherein 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 driving mechanism, which is a swing motor, used to drive the polishing head to swing so as to change the contact state between the polishing head and the edge of the wafer.

2. The wafer edge polishing device according to claim 1, characterized in that: The polishing head is equipped with a vertical driving mechanism, which is a linear moving module to drive the polishing head to move along the length direction of the output shaft of the vertical driving mechanism; the vertical driving mechanism is arranged on a fixed seat, and the fixed seat is arranged on the side of the rotating mechanism.

3. The wafer edge polishing device according to claim 2, characterized in that: The vertical driving mechanism is connected to the horizontal driving mechanism through a bracket. The horizontal driving mechanism is a linear moving module, and the moving block thereon moves along the slide rail to drive the fixed seat and the polishing head thereon to move horizontally, thereby approaching or moving away from the edge of the wafer.

4. The wafer edge polishing device according to claim 3, characterized in that: The output shaft of the swing driving mechanism is connected to the fixing seat to drive the fixing seat and the polishing head thereon to swing.

5. The wafer edge polishing device according to claim 1, characterized in that: The polishing belt is led out from the unwinding drum and introduced into the winding drum via a plurality of guide wheels; the unwinding drum and the winding drum are arranged at intervals on the side of the vertical plate along the vertical direction.

6. The wafer edge polishing device according to claim 5, characterized in that: The unwinding drum is installed on the output shaft of the unwinding motor, and the winding drum is installed 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 device according to claim 2, characterized in that: The fixing seat is arranged on the upper side and / or the lower side of the tray of the rotating mechanism, so as to drive the polishing head to approach or move away from the edge of the wafer through the vertical driving mechanism.

8. The wafer edge polishing device according to claim 1, characterized in that: The number of the polishing components is four, and they are dispersedly arranged outside the wafer to be processed so as to process the edge of the wafer through the polishing belt.

9. The wafer edge polishing device according to claim 1, characterized in that: The polishing head also includes an extrusion portion, which is arranged between the inclined portion and the arc portion to press downward through the polishing belt and then feed the edge of the processed wafer vertically; the junction between the extrusion portion and the inclined portion adopts an arc transition.

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

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

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

13. A wafer edge polishing method, characterized in that: The wafer edge polishing device according to any one of claims 1 to 12 comprises: The rotating mechanism loads the wafer and drives the wafer to rotate around the central axis; The vertical driving mechanism moves the polishing head downward to a set position; The horizontal driving mechanism moves the polishing head horizontally to the edge of the wafer; The vertical driving mechanism continues to move downward to press against the edge of the rotating wafer through the polishing belt; The horizontal driving mechanism continues to move horizontally to form an annular opening at the edge of the wafer; The swing driving mechanism swings the fixed seat and the polishing head thereon, so that the polishing belt outside the polishing head contacts the edges and corners of the annular opening; The swing driving mechanism drives the polishing head to swing 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 the surface with abrasive particles attached.

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

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