Wafer edge polishing apparatus and polishing method

Abstract

This invention discloses a wafer edge polishing apparatus and polishing method, relating to the field of wafer processing technology. The wafer edge polishing apparatus includes: a loading and rotating mechanism for loading and driving a wafer to rotate around a central axis; a polishing assembly that presses a polishing strip against the edge of the wafer to achieve wafer polishing; the polishing assembly includes an upper polishing head, a lower polishing head, and an edge polishing head, which polishes the upper surface, lower surface, and / or edge of the wafer through lateral and longitudinal feeds; the polishing assembly further includes a timing drive assembly and a horizontal drive assembly, the timing drive assembly being connected to the upper and lower polishing heads to control the longitudinal feed of the upper and lower polishing heads to polish the upper surface and / or lower surface of the wafer edge; the horizontal drive assembly being connected to the edge polishing head to control the lateral feed of the edge polishing head to polish the edge of the wafer.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a wafer edge polishing apparatus and polishing method. Background Technology

[0002] In existing wafer fabrication processes, after multiple processing steps such as etching, sharp burrs or uneven thickness are easily present on the wafer edges. This can lead to uneven stress during subsequent processing, causing the wafer to break and affecting product yield.

[0003] Wafer edge polishing process is divided into edge upper and lower surface polishing and edge polishing. Existing wafer edge polishing mechanisms are equipped with only one polishing head, and a single polishing head needs to be flipped multiple times to complete the edge polishing process.

[0004] The wafer edge polishing process requires three processes: edge upper and lower surface polishing and edge polishing. The polishing head structure needs to be flipped multiple times to complete the three polishing processes, which will affect the wafer processing efficiency. In addition, the flipping action of the polishing head structure requires a large space, which increases the space occupied by the wafer edge processing equipment and is not conducive to the rational layout of equipment in the fab.

[0005] Furthermore, during the polishing of the upper and lower surfaces of the edge, the positive pressure of a single polishing head on the wafer can cause the wafer to become unstable and deformed, affecting the polishing effect and potentially causing the wafer to break. Summary of the Invention

[0006] In view of this, embodiments of this application provide a wafer edge polishing apparatus and polishing method to at least partially solve the above-mentioned problems.

[0007] According to a first aspect of the embodiments of this application, a wafer edge polishing apparatus is provided, comprising:

[0008] A loading and rotating mechanism is used to load and rotate the wafer around its central axis;

[0009] A polishing assembly that presses a polishing strip against the edge of the wafer to achieve wafer polishing;

[0010] The polishing assembly includes an upper polishing head, a lower polishing head, and an edge polishing head, which achieves polishing of the upper surface, lower surface, and / or edge of the wafer through lateral and longitudinal feeding.

[0011] The polishing assembly further includes a timing drive assembly and a horizontal drive assembly. The timing drive assembly is connected to the upper polishing head and the lower polishing head to control the longitudinal feed of the upper polishing head and the lower polishing head to polish the upper surface and / or lower surface of the wafer edge. The horizontal drive assembly is connected to the edge polishing head to control the lateral feed of the edge polishing head to polish the edge of the wafer.

[0012] In some embodiments, the timing transmission assembly includes a control shaft, an upper support shaft for fixing the upper polishing head, and a lower support shaft for fixing the lower polishing head, all three being arranged laterally. The control shaft is located between the upper support shaft and the lower support shaft. The control shaft is axially provided with a control wheel, which meshes with gears on the upper and lower support shafts to adjust the longitudinal position of the upper and lower polishing heads.

[0013] In some embodiments, the control shaft is configured with a first control wheel and a second control wheel, which are spaced apart; the first control wheel meshes with the upper gear of the upper support shaft, and the second control wheel meshes with the lower gear of the lower support shaft, so as to drive the rotation of the cams of the upper and lower support shafts, thereby changing the longitudinal position of the upper and lower polishing heads.

[0014] In some embodiments, the first control wheel and the second control wheel are incomplete gears to control their meshing with the upper gear and the lower gear, thereby adjusting the longitudinal position of the upper polishing head and the lower polishing head.

[0015] In some embodiments, the first control wheel is a pair of sector gears, each sector gear being 1 / 4 of a circle, and the two are symmetrically arranged around the center of the circle; the second control wheel is a semi-circular gear.

[0016] In some embodiments, the timing transmission component has at least three states: the first control wheel is engaged with the upper gear and the second control wheel is not engaged with the lower gear; the first control wheel is engaged with the upper gear and the second control wheel is engaged with the lower gear; the first control wheel is not engaged with the upper gear and the second control wheel is engaged with the lower gear.

[0017] In some embodiments, a sector gear of the first control wheel overlaps with the second control wheel in the circumferential direction.

[0018] In some embodiments, the first control wheel and the second control wheel do not overlap at all in a 1 / 4 region of the circumference.

[0019] In some embodiments, the ends of the upper support shaft and the lower support shaft are provided with fixing components. The fixing components include a fixing seat and a support plate. The support plate is connected to the fixing seat by a slider. An upper polishing head and a lower polishing head are provided on the support plate.

[0020] In some embodiments, the fixed base is provided with a vertical groove, a transverse connecting rod is provided on the side of the slider, the connecting rod passes through the groove, and a transmission roller is provided on the side of the connecting rod; the cams of the upper support shaft and the lower support shaft abut against the transmission roller, so that the connecting rod on the slider moves along the length direction of the groove to change the position of the support plate.

[0021] In some embodiments, the end of the connecting rod is provided with an adapter frame, the adapter frame being a U-shaped frame, and the transmission roller is rotatably connected to the adapter frame; the setting position of the transmission roller matches the setting position of the cam, such that the surface of the transmission roller abuts against the contour surface of the cam.

[0022] In some embodiments, the upper polishing head and the lower polishing head include a support block and a pad, the support block is disposed on the support plate, the pad is stacked on the support block, and the polishing belt passes around guide rollers disposed on both sides of the pad and covers the outside of the pad.

[0023] In some embodiments, the support block is a trapezoidal block, and the pad is disposed above the small cross-section of the trapezoidal block.

[0024] In some embodiments, the pad is made of a malleable non-metallic material and its length matches the width of the polishing strip.

[0025] In some embodiments, the horizontal transmission assembly includes a vertical plate and a horizontal actuator, the horizontal actuator being disposed on the side of the vertical plate, and its moving end being provided with an edge polishing head; the edge polishing head has the same structure as the upper polishing head and the lower polishing head.

[0026] According to a second aspect of the embodiments of this application, a wafer edge polishing method is provided, which uses the wafer edge polishing apparatus described above, including:

[0027] Step 1: Place the wafer to be processed onto the tray of the rotating loading mechanism;

[0028] Step 2: The polishing head of the polishing assembly is fed laterally and / or longitudinally, so that the polishing strip comes into contact with the upper surface, lower surface and / or edge of the wafer.

[0029] Step 3: The polishing belt is moved to polish the upper surface, lower surface and / or edges of the wafer.

[0030] In some embodiments, two of the polishing heads of the polishing assembly operate simultaneously to polish the wafer edge.

[0031] In some embodiments, when the upper or lower polishing head processes the wafer edge alone, the pad of the other polishing head abuts against the wafer surface, and the pad is not covered with the polishing tape.

[0032] In some embodiments, the timing transmission assembly drives the control shaft to rotate, causing the first control wheel to mesh with the upper gear and the second control wheel to mesh with the lower gear, thereby causing the polishing belts of the upper and lower polishing heads to abut against the upper and lower surfaces of the wafer, respectively, to achieve polishing of the upper and lower surfaces of the wafer.

[0033] In some embodiments, after the upper and lower surfaces of the wafer are polished, the horizontal transmission assembly controls the edge polishing head to move horizontally, and the polishing belt on it abuts against the edge of the wafer to complete the polishing of the edge of the wafer.

[0034] In some embodiments, the working area of ​​the edge polishing head overlaps with the working areas of the upper polishing head and the lower polishing head.

[0035] The beneficial effects of this invention include:

[0036] a. The provided wafer edge polishing device is equipped with an independent upper polishing head, a lower polishing head, and an edge polishing head, which can achieve wafer edge polishing through transverse and / or longitudinal feed, thereby improving the flexibility of edge processing;

[0037] b. The upper polishing head, lower polishing head and edge polishing head of the polishing assembly do not need to process the wafer edge by oscillating around a fixed point, which simplifies the structure of the polishing assembly and helps to ensure the stability of the polishing assembly operation;

[0038] c. The upper polishing head, lower polishing head, and edge polishing head can be combined in pairs to process the edge of the wafer, so that the wafer does not warp or deform to one side. This prevents the negative impact of warping and deformation caused by processing the edge of the wafer on the polishing quality and ensures the polishing quality of the wafer edge.

[0039] d. The working area of ​​the edge polishing head overlaps with the working areas of the upper and lower polishing heads. That is, when the edge polishing head finishes processing the wafer edge, it can cover the processing marks left by the upper and lower polishing heads, thereby avoiding the impact of marks left by a single polishing head on the wafer edge polishing effect;

[0040] e. The polishing assembly is equipped with a timing drive assembly that can control the longitudinal position of the upper and lower polishing heads to selectively process the upper and lower surfaces of the wafer;

[0041] f. The first and second control wheels of the timing drive assembly are mounted on the control shaft with a fixed phase angle, so as to change the operating state of the upper and lower polishing heads by driving the control wheels to rotate;

[0042] g. The first and second control wheels are incomplete gears to control their meshing with the upper and lower gears, thereby adjusting the longitudinal position of the upper and lower polishing heads.

[0043] h. Cams are provided on the upper and lower support shafts. The cams abut against the drive rollers connected to the upper and lower polishing heads to ensure the position of the polishing head of the polishing assembly by driving and maintaining the state of the upper and / or lower support shafts, so that the polishing belt abuts against a specific working area on the edge of the wafer.

[0044] i. The pad of the polishing head is made of a malleable non-metallic material that can be deformed to ensure that the polishing strip covering the outside of the pad fits tightly against the surface to be polished, thus ensuring the effect of edge polishing. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0046] Figure 1 This is a schematic diagram of a wafer edge polishing apparatus provided in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the working area corresponding to the wafer edge being processed by a polishing head according to an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of a polishing assembly provided in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of a cam disposed on an upper support shaft according to an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the connection between the upper support shaft and the upper polishing head according to an embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of a fixing base provided in an embodiment of the present invention;

[0052] Figure 7 This is a schematic diagram of a fixing assembly for removing the fixing base according to an embodiment of the present invention;

[0053] Figure 8 This is a schematic diagram of an upper polishing head provided in an embodiment of the present invention;

[0054] Figure 9 yes Figure 3 A schematic diagram of the polishing components from another perspective;

[0055] Figure 10 This is a schematic diagram of a control wheel disposed on a control shaft according to an embodiment of the present invention;

[0056] Figure 11 This is a side view of the first and second control wheels located on the control axis;

[0057] Figure 12 This is a flowchart of a wafer edge polishing method provided in an embodiment of the present invention;

[0058] Figure 13 This is a schematic diagram of the overlapping region of the wafer edge provided in an embodiment of the present invention. Detailed Implementation

[0059] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0060] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0061] 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 information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0062] In the embodiments of the application, a wafer (W) is also called a substrate, which has the same meaning and actual function.

[0063] Figure 1 This is a schematic diagram of a wafer edge polishing apparatus 100 provided in an embodiment of the present invention. The wafer edge polishing apparatus 100 includes:

[0064] The loading and rotating mechanism 10 is used to load and drive the wafer W to rotate around the central axis;

[0065] Polishing assembly 20, which will polishing belt 20a ( Figure 5 (As shown) is pressed against the edge of the wafer to achieve wafer polishing.

[0066] Furthermore, the loading and rotating mechanism 10 includes a tray 11, indicated by dashed lines, with a rotary motor positioned below it. The rotary motor drives the tray and the wafer W on it to rotate around a central axis. Since the wafer W is concentrically positioned above the tray of the loading and rotating mechanism 10, it can also be said that the loading and rotating mechanism drives the wafer to rotate around its central axis. The tray has grooves / channels inside, which are connected to a vacuum source via pipes to create a negative pressure between the tray and the wafer W, thereby adsorbing the wafer W to be polished onto the upper surface of the tray.

[0067] Figure 1 In the process, the polishing assembly 20 includes an upper polishing head 21, a lower polishing head 22, and an edge polishing head 23, which polishes the upper surface S1, lower surface S2, and / or edge portion S3 of the wafer through lateral and longitudinal feeding; wherein, Figure 2 The diagram roughly illustrates the various working areas of wafer edge polishing. Edge polishing removes the sharp edges of the wafer edges to eliminate stress concentration caused by the sharp edges, making the wafer edges smoother.

[0068] In this invention, the polishing assembly 20 further includes a timing transmission assembly 30, which is connected to the upper polishing head 21 and the lower polishing head 22 to control the longitudinal feed of the upper polishing head 21 and the lower polishing head 22, thereby processing the upper surface and / or lower surface of the wafer edge.

[0069] Furthermore, the polishing assembly 20 also includes a horizontal transmission assembly 40, which is connected to the edge polishing head 23 to control the lateral feed of the edge polishing head 23, thereby processing the edge of the wafer.

[0070] Figure 3 This is a schematic diagram of a polishing assembly 20 provided in an embodiment of the present invention. The timing transmission assembly 30 includes a control shaft 31, an upper support shaft 32, and a lower support shaft 33, which are arranged parallel to the horizontal plane. The upper support shaft 32 is used to fix the upper polishing head 21, the lower support shaft 33 is used to fix the lower polishing head 22, and the control shaft 31 is arranged laterally between the upper support shaft 32 and the lower support shaft 33.

[0071] Furthermore, the control shaft 31 is equipped with two control wheels 34, namely a first control wheel 34a and a second control wheel 34b, which are spaced apart along the axial direction of the control shaft 31. The control wheels 34 mesh with the gears 35 of the upper support shaft 32 and the lower support shaft 33 to adjust the longitudinal position of the upper polishing head 21 and the lower polishing head 22.

[0072] Specifically, an upper gear 35a is disposed on the upper support shaft 32, and its position is opposite to the first control wheel 34a on the control shaft 31 so that the first control wheel 34a meshes with the upper gear 35a; correspondingly, a lower gear 35b is disposed on the lower support shaft 33, and its position is opposite to the second control wheel 34b on the control shaft 31 so that the second control wheel 34b meshes with the lower gear 35b.

[0073] It should be noted that the outer circumferential surface of the control wheel 34 is equipped with teeth that mesh with the gear 35. Figure 3 The general shape of the control wheel 34 is only shown schematically; the control wheel 34 meshes with the gear 35 to drive the upper support shaft 32 and the lower support shaft 33 to rotate around their axes.

[0074] Figure 3 In the embodiment shown, cams 36 are disposed on the upper support shaft 32 and the lower support shaft 33. The rotation of the upper support shaft 32 and the lower support shaft 33 can change the contour shape of the cam 36 and the contact state with the follower, thereby adjusting the longitudinal position of the upper polishing head 21 and the lower polishing head 22.

[0075] In this invention, the structure and connection relationship of the cam 36 of the upper support shaft 32 are the same as those of the cam 36 of the lower support shaft 33.

[0076] Figure 4 A schematic diagram shows a cam 36 mounted on an upper support shaft 32. The cam 36 has a profile that is convex on one side and circular on the opposite side, with a relatively smooth transition between the two. The cam 36 rotates around the upper support shaft 32, and the shape of its outer profile determines the motion pattern of the follower. The follower here is the drive roller 55 mentioned below, which can drive the upper polishing head 21 to move vertically, thereby changing its longitudinal position.

[0077] In this invention, fixing components 50 are disposed at the ends of the upper support shaft 32 and the lower support shaft 33 to fix the upper polishing head 21 and the lower polishing head 22, respectively. Since the fixing components 50 disposed on the upper support shaft 32 and the lower support shaft 33 have the same structure, they will be referred to as... Figure 5 Taking the fixed component 50 set on the upper support shaft 32 as an example, the structural composition and connection relationship of the fixed component 50 are explained.

[0078] The fixing component 50 includes a fixing base 51 and a support plate 52, such as Figure 5 As shown, the fixed seat 51 is located at the end of the upper support shaft 32, the support plate 52 has an L-shaped structure, and it is connected to the side of the fixed seat 51 by a slider 53. The upper polishing head 21 is located on the support plate 52.

[0079] Furthermore, the fixed base 51 is provided with a sliding groove 51a, such as Figure 6As shown, the chute 51a is a through groove, which is set vertically.

[0080] The slider 53 is configured with a side Figure 7 The connecting rod 54 shown is arranged laterally and passes through the slide groove 51a of the fixed seat 51. The end of the connecting rod 54 is equipped with a transmission roller 55. The cam 36 abuts against the transmission roller 55 so as to change the vertical position of the slider 53 fixed by the connecting rod 54 as the contour of the cam 36 changes, so that the connecting rod 54 on the slider 53 moves along the length direction of the slide groove 51a to change the position of the support plate 52, that is, to change the longitudinal position of the support plate 52 and the upper polishing head 21 on it.

[0081] Figure 7 In the embodiment shown, the end of the connecting rod 54 is provided with an adapter frame 56, which is a U-shaped frame, and the transmission roller 55 is rotatably connected to the adapter frame 56 via a rotating shaft.

[0082] Furthermore, the position of the transmission roller 55 is matched with the position of the cam 36, so that the surface of the transmission roller 55 abuts against the contour surface of the cam 36, so that the rotating cam 36 drives the slider 53 to move up and down, thereby changing the vertical position of the support plate 52 and the upper polishing head 21 on it.

[0083] The upper polishing head 21 includes a support block 21a and a pad 21b, such as Figure 8 As shown, the support block 21a is disposed on the side of the support plate 52; that is, the pad 21b is stacked on the side of the support block 21a.

[0084] Furthermore, the support block 21a is a trapezoidal block, and the pad 21b is disposed above the small cross-section of the trapezoidal block, such as... Figure 5 As shown, this allows the polishing belt 20a to cover the outside of the pad 21b without interfering with the edge of the support block 21a, thereby maintaining the polishing belt in a well-treated state.

[0085] In this invention, the pad 21b is made of a malleable non-metallic material so that the polishing strip on the outer side of the pad 21b can adapt to the contour of the wafer edge and fit completely with the surface of the wafer to be polished, so as to obtain polishing quality that meets the process requirements.

[0086] Furthermore, the length of the pad 21b is matched with the width of the polishing belt, so that the moving polishing belt is in continuous contact with the surface of the wafer to be processed, thereby ensuring the efficiency of wafer edge polishing.

[0087] The polishing belt passes over the guide rollers 57 located on both sides of the pad 21b and covers the outside of the pad 21b. Specifically, the guide rollers 57 are mounted on the fixed base 51 and symmetrically arranged on both sides of the pad 21b; the polishing belt 20a passes over one guide roller 57, the pad 21b and another guide roller 57 in sequence and covers the outside of the pad 21b.

[0088] Figure 3 In the illustrated embodiment, the horizontal transmission assembly 40 includes a vertical plate 41 and a horizontal actuator 42, wherein the horizontal actuator 42 is disposed on the side of the vertical plate 41, and its moving end is equipped with an edge polishing head 23. A guide roller 57 defining the polishing belt is disposed on the vertical plate 41, as shown. Figure 3 As shown, the edge polishing head 23 is roughly the same as the upper polishing head 21 and the lower polishing head 22, and will not be described in detail here.

[0089] It should be noted that the horizontal actuator 42 can be a linear motion module such as a cylinder or an electric cylinder. The edge polishing head 23 is located at the moving end of the horizontal actuator 42 so that the polishing strip covered by the edge polishing head 23 is brought into contact with the edge of the wafer to polish the edge of the wafer.

[0090] Figure 9 In the embodiment shown, the first control wheel 34a and the second control wheel 34b are incomplete gears to control their meshing with the upper gear 35a and the lower gear 35b, thereby adjusting the longitudinal position of the upper polishing head 21 and the lower polishing head 22.

[0091] Furthermore, the first control wheel 34a is a pair of sector gears, each sector gear being 1 / 4 of the circumference, and the two are symmetrically arranged along the center of the circle, that is, the central angle corresponding to the sector gear is 90°; the second control wheel 34b is a semi-circular gear, and its corresponding central angle is 180°.

[0092] Figure 10 This is a schematic diagram of a control wheel 34 disposed on a control shaft 31 according to an embodiment of the present invention. The first control wheel 34a and the second control wheel 34b are spaced apart along the axial direction of the control shaft 31. Furthermore, the first control wheel 34a and the second control wheel 34b are mounted on the control shaft 31 with a relatively fixed phase angle, so that the timing transmission assembly 30 can exist in at least the following three states:

[0093] State 1: The first control wheel 34a is engaged with the upper gear 35a, and the second control wheel 34b is not engaged with the lower gear 35b;

[0094] State 2: The first control wheel 34a meshes with the upper gear 35a, and the second control wheel 34b meshes with the lower gear 35b;

[0095] State 3: The first control wheel 34a is not engaged with the upper gear 35a, and the second control wheel 34b is engaged with the lower gear 35b.

[0096] When the timing transmission assembly 30 is in state one, the first control wheel 34a meshes only with the upper gear 35a, and the upper support shaft 32 rotates around its axis to abut against the transmission roller 55 via the cam 36. This causes the upper polishing head 21 to change its position as the support plate 52 moves vertically, and the polishing belt covering the outer side of the pad 21b of the upper polishing head 21 abuts against the upper surface S1 of the wafer. Figure 2 (As shown), to polish the upper surface of the edge of the wafer.

[0097] When the timing transmission assembly 30 is in state two, the first control wheel 34a meshes with the upper gear 35a, and the second control wheel 34b meshes with the lower gear 35b, so as to simultaneously control the upper polishing head 21 and the lower polishing head 22 to move toward the wafer, so that the corresponding polishing belt abuts against the upper and lower surfaces of the wafer edge to polish the upper and lower surfaces of the wafer edge.

[0098] Since the upper polishing head 21 and the lower polishing head 22 simultaneously abut against the upper and lower surfaces of the wafer, the wafer does not warp or deform to one side, thus preventing the negative impact of warping deformation caused by processing on one side of the wafer edge on the polishing quality and ensuring the polishing quality of the wafer edge.

[0099] When the timing transmission assembly 30 is in state three, the second control wheel 34b meshes with the lower gear 35b, and the lower support shaft 33 rotates around its axis to abut against the transmission roller 55 via the cam 36. This causes the lower polishing head 22 to change its position as the support plate 52 moves vertically, and the polishing belt covering the outer side of the pad 21b of the lower polishing head 22 abuts against the lower surface S2 of the wafer. Figure 2 (As shown), to polish the lower surface of the edge of the wafer.

[0100] In this invention, when the control wheel 34 is fixed to the control shaft 31, a sector gear of the first control wheel 34a overlaps with the second control wheel 34b in the circumferential direction, as shown below. Figure 11 As shown, in the second state corresponding to the timing transmission component 30, the two control wheels 34 are respectively engaged with the upper gear 35a and the lower gear 35b to control the upper polishing head 21 and the lower polishing head 22 to polish the edge of the wafer simultaneously.

[0101] It should be noted that the timing drive assembly 30 also exists in state four: the first control wheel 34a does not mesh with the upper gear 35a, and the second control wheel 34b does not mesh with the lower gear 35b; in this state, the control wheel 34 does not mesh with the upper gear 35a and the lower gear 35b, that is, the upper polishing head 21 and the lower polishing head 22 do not polish the edge of the wafer at the same time.

[0102] To achieve state four, when control wheel 34 is fixed to control shaft 31, the first control wheel 34a and the second control wheel 34b do not overlap at all in the 1 / 4 region of the circumference, as shown below. Figure 11 As shown, this prevents the control wheel 34 from meshing with the upper gear 35a and the lower gear 35b.

[0103] It is understandable that when the timing drive assembly 30 is in state four, the upper polishing head 21 and the lower polishing head 22 of the polishing assembly 20 do not process the edge of the wafer. At this time, the horizontal drive assembly 40 can be controlled to use the edge polishing head 23 to process the edge of the wafer.

[0104] According to a second aspect of the embodiments of this application, a wafer edge polishing method is provided, which uses... Figure 1 The wafer edge polishing apparatus 100 shown is illustrated in the flowchart of the wafer edge polishing method, as follows: Figure 12 As shown, it includes:

[0105] Step 1: Place the wafer to be processed on the tray 11 of the rotating mechanism 10;

[0106] Specifically, an external robotic arm transfers the wafer to be processed to a tray 11 of a loading and rotating mechanism 10, and the wafer is concentrically arranged on the tray 11 to provide a reference for the control of the polishing assembly 20; the tray 11 holds the wafer by vacuum adsorption and the loading and rotating mechanism 10 drives the tray 11 and the wafer on it to rotate.

[0107] Step 2: The polishing head of the polishing assembly 20 is fed laterally and / or longitudinally, so that the polishing belt abuts against the upper surface, lower surface and / or edge of the wafer.

[0108] Specifically, the polishing assembly 20 controls the lateral and / or longitudinal feed of the polishing head through the timing transmission assembly 30 and the horizontal transmission assembly 40, so that the polishing belt comes into contact with the area to be processed;

[0109] Step 3: The polishing belt is moved to polish the upper surface, lower surface and / or edges of the wafer.

[0110] After the polishing head is moved into position, the polishing belt moves to process the upper surface, lower surface and / or edge of the wafer through the polishing belt.

[0111] In step two, two polishing heads of the polishing assembly 20 operate simultaneously to polish the wafer edge. Specifically, the upper polishing head 21 and the lower polishing head 22 simultaneously process the wafer edge, the upper polishing head 21 and the edge polishing head 23 simultaneously process the wafer edge, or the lower polishing head 22 and the edge polishing head 23 simultaneously process the wafer edge. In the above processing method, the upper surface, lower surface, and at least two portions of the edge of the wafer are subjected to the load applied by the polishing head, which can, to a certain extent, prevent the wafer edge from being warped by off-center loading, thereby ensuring the processing quality of the wafer edge.

[0112] When the upper polishing head 21 and the lower polishing head 22 process the edge of the wafer simultaneously, the timing transmission assembly 30 drives the control shaft 31 to rotate, so that the first control wheel 34a meshes with the upper gear 35a and the second control wheel 34b meshes with the lower gear 35b. Then, the polishing belts of the upper polishing head 21 and the lower polishing head 22 respectively abut against the upper and lower surfaces of the wafer to achieve polishing of the upper and lower surfaces of the wafer.

[0113] After the upper and lower surfaces of the wafer are polished, the horizontal transmission assembly 40 controls the edge polishing head 23 to move horizontally, and the polishing belt on it abuts against the edge of the wafer. Figure 2 As shown in S3), the edge of the wafer is polished.

[0114] In some embodiments, the working area of ​​the edge polishing head 23 overlaps with the working areas of the upper polishing head 21 and the lower polishing head 22 (e.g., ...). Figure 13 (As shown). That is, when the edge polishing head 23 is used to process the edge of the wafer, it can cover the processing marks left by the upper polishing head 21 and the lower polishing head 22, thereby avoiding the marks left by a single polishing head from affecting the effect of wafer edge polishing.

[0115] In this invention, the length of the overlapping region So is less than or equal to 1 / 4 of the upper surface S1 or the lower surface S2, so that the marks left by the action of a single polishing head can be eliminated by the action of the edge polishing head 23, thus ensuring the effect of wafer edge polishing.

[0116] Understandably, either the upper polishing head 21 or the lower polishing head 22 can process the wafer edge independently. When the upper polishing head 21 or the lower polishing head 22 processes the wafer edge independently, the pad 21b of the other polishing head abuts against the wafer surface, and the pad 21b does not cover the polishing tape. With this configuration, the pad 21b of the other polishing head can provide support for the wafer to prevent wafer warping and deformation that would affect the edge polishing quality.

[0117] Understandably, each polishing head of the polishing assembly 20 can simultaneously process the upper surface, lower surface, and edge of the wafer. Since the polishing bands of adjacent polishing heads may interfere with each other, the edge polishing head 23 is finally used to process the edge of the wafer as a whole to avoid traces left by a single polishing head and to ensure the quality of the wafer edge polishing.

[0118] Those skilled in the art will recognize that the units and method steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0119] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A wafer edge polishing apparatus, characterized by comprising: include: A loading and rotating mechanism is used to load and rotate the wafer around its central axis; A polishing assembly that presses a polishing strip against the edge of the wafer to achieve wafer polishing; The polishing assembly includes an upper polishing head, a lower polishing head, and an edge polishing head, which achieves polishing of the upper surface, lower surface, and / or edge of the wafer through lateral and longitudinal feeding. The polishing assembly further includes a timing drive assembly and a horizontal drive assembly. The timing drive assembly is connected to the upper polishing head and the lower polishing head to control the longitudinal feed of the upper polishing head and the lower polishing head to polish the upper surface and / or lower surface of the wafer edge. The horizontal drive assembly is connected to the edge polishing head to control the lateral feed of the edge polishing head to polish the edge portion of the wafer. The timing transmission assembly includes a control shaft, an upper support shaft for fixing the upper polishing head, and a lower support shaft for fixing the lower polishing head. The three are arranged laterally, and the control shaft is located between the upper support shaft and the lower support shaft. The control shaft has a control wheel arranged axially, which meshes with the gears of the upper support shaft and the lower support shaft to adjust the longitudinal position of the upper polishing head and the lower polishing head. The control shaft is equipped with a first control wheel and a second control wheel, which are spaced apart. The first control wheel meshes with the upper gear of the upper support shaft, and the second control wheel meshes with the lower gear of the lower support shaft, so as to drive the rotation of the cams of the upper and lower support shafts, thereby changing the longitudinal position of the upper and lower polishing heads. The first and second control wheels are incomplete gears to control their meshing with the upper and lower gears, thereby adjusting the longitudinal position of the upper and lower polishing heads. The timing transmission component has at least three states: the first control wheel is engaged with the upper gear and the second control wheel is not engaged with the lower gear; the first control wheel is engaged with the upper gear and the second control wheel is engaged with the lower gear; the first control wheel is not engaged with the upper gear and the second control wheel is engaged with the lower gear.

2. The wafer edge polishing apparatus according to claim 1, characterized in that, The first control wheel is a pair of sector gears, each sector gear being 1 / 4 of a circle, and the two are symmetrically arranged along the center of the circle; the second control wheel is a semi-circular gear.

3. The wafer edge polishing apparatus according to claim 1, characterized in that, One sector gear of the first control wheel overlaps with the second control wheel in the circumferential direction.

4. The wafer edge polishing apparatus according to claim 1, characterized in that, The first control wheel and the second control wheel do not overlap at all in the 1 / 4 region of the circumference.

5. The wafer edge polishing apparatus according to claim 1, characterized in that, The ends of the upper and lower support shafts are equipped with fixing components. The fixing components include a fixing seat and a support plate. The support plate is connected to the fixing seat by a slider. An upper polishing head and a lower polishing head are arranged on the support plate.

6. The wafer edge polishing apparatus according to claim 5, characterized in that, The fixed base is provided with a vertical groove, and a horizontal connecting rod is provided on the side of the slider. The connecting rod passes through the groove, and a transmission roller is provided on the side of the connecting rod. The cams on the upper support shaft and the lower support shaft abut against the transmission roller, so that the connecting rod on the slider moves along the length of the groove to change the position of the support plate.

7. The wafer edge polishing apparatus according to claim 6, characterized in that, The end of the connecting rod is equipped with an adapter frame, which is a U-shaped frame, and the transmission roller is rotatably connected to the adapter frame; the setting position of the transmission roller matches the setting position of the cam, so that the surface of the transmission roller abuts against the contour surface of the cam.

8. The wafer edge polishing apparatus according to claim 5, characterized in that, The upper polishing head and the lower polishing head include a support block and a pad. The support block is disposed on the support plate, and the pad is stacked on the support block. The polishing belt passes around the guide rollers disposed on both sides of the pad and covers the outside of the pad.

9. The wafer edge polishing apparatus according to claim 8, characterized in that, The support block is a trapezoidal block, and the pad is disposed above the small cross-section of the trapezoidal block.

10. The wafer edge polishing apparatus according to claim 8, characterized in that, The pad is made of a malleable non-metallic material and its length matches the width of the polishing strip.

11. The wafer edge polishing apparatus according to claim 1, characterized in that, The horizontal transmission assembly includes a vertical plate and a horizontal actuator. The horizontal actuator is disposed on the side of the vertical plate, and its moving end is equipped with an edge polishing head. The edge polishing head has the same structure as the upper polishing head and the lower polishing head.

12. A method for polishing wafer edges, characterized in that, Using the wafer edge polishing apparatus according to any one of claims 1-11, comprising: Step 1: Place the wafer to be processed onto the tray of the rotating loading mechanism; Step 2: The polishing head of the polishing assembly is fed laterally and / or longitudinally, so that the polishing strip comes into contact with the upper surface, lower surface and / or edge of the wafer. Step 3: The polishing belt is moved to polish the upper surface, lower surface and / or edges of the wafer.

13. The wafer edge polishing method according to claim 12, characterized in that, Two of the polishing heads in the polishing assembly operate simultaneously to polish the wafer edges.

14. The wafer edge polishing method according to claim 12, characterized in that, When the upper or lower polishing head processes the wafer edge alone, the pad of the other polishing head abuts against the wafer surface, and the pad is not covered with the polishing tape.

15. The wafer edge polishing method according to claim 12, characterized in that, The timing transmission assembly drives the control shaft to rotate, causing the first control wheel to mesh with the upper gear and the second control wheel to mesh with the lower gear. As a result, the polishing belts of the upper and lower polishing heads respectively abut against the upper and lower surfaces of the wafer to achieve polishing of the upper and lower surfaces of the wafer.

16. The wafer edge polishing method according to claim 15, characterized in that, After the upper and lower surfaces of the wafer are polished, the horizontal transmission assembly controls the edge polishing head to move horizontally, and the polishing belt on it abuts against the edge of the wafer to complete the polishing of the edge of the wafer.

17. The wafer edge polishing method according to claim 12, characterized in that, The working area of ​​the edge polishing head overlaps with the working areas of the upper and lower polishing heads.

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