Grinding wheel feeding device and silicon wafer thinning machine

Abstract

The present invention provides a grinding wheel feeding device and a silicon wafer thinning machine. The grinding wheel feeding device includes: a grinding wheel; a fixed seat having a mounting hole penetrating in the vertical direction; a first driving assembly, the first driving assembly includes a seat body installed in the mounting hole and a rotating shaft rotatably connected to the seat body, there is a gap between the seat body and the mounting hole, and the grinding wheel is connected to the rotating shaft; a fine adjustment mechanism, the fine adjustment mechanism includes at least three adjustment components spaced circumferentially along the mounting hole, each of the adjustment components is connected between the fixed seat and the seat body and is used to adjust the downward displacement at the position of the first driving assembly corresponding to the adjustment component; micro-feed in the Z-axis direction can be carried out according to specific requirements to improve the stability of the thinning process. At the same time, by controlling the different downward displacements of the plurality of adjustment components, high-precision tilting adjustment of the grinding wheel in the X-axis and Y-axis directions can be achieved, and the precision of silicon wafer grinding can be improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor processing and production, and particularly to a grinding wheel feeding device and a wafer thinning machine. Background Art

[0002] The wafer thinning machine is mainly used for surface processing in the preparation stage of the substrate wafer, and for removing the redundant substrate material on the back surface of the wafer before integrated circuit packaging. With the rapid development of IC manufacturing technology, the development trend of large diameter and ultra-thin of wafers puts forward higher requirements for the processing efficiency and quality of wafer grinding.

[0003] The grinding wheel feeding device in the existing wafer thinning machine is generally set as a motor screw mechanism for driving the grinding wheel to move up and down. However, the minimum micro-feed amount of the grinding wheel driven by the motor screw mechanism can only reach the micron level at the lowest, which is difficult to meet the existing process requirements, and is likely to cause micro-cracked surfaces on the wafer surface. Finally, a polishing process is required to remove the micro-cracked surfaces, and the process is relatively complex. At the same time, during the working process of the grinding wheel, due to its own consumption, its thickness will decay to varying degrees, resulting in inconsistent thickness of the ground wafers, and poor precision of wafer grinding and thinning.

[0004] In view of this, it is necessary to provide an improved grinding wheel feeding device and a wafer thinning machine to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a grinding wheel feeding device and a wafer thinning machine with the grinding wheel feeding device. The grinding wheel feeding device can achieve a micro-feed amount of the grinding wheel less than 100 nm at a time, reducing the generation of micro-cracks on the wafer surface. At the same time, it can achieve high-precision tilting adjustment of the grinding wheel, and can achieve adjustment of different thinning thicknesses for the center and edge of the wafer, improving the precision of wafer grinding.

[0006] To achieve the above invention purpose, the present invention adopts the following technical solutions: A grinding wheel feeding device, comprising:

[0007] A grinding wheel;

[0008] A fixed seat, the fixed seat having an installation hole penetrating in the up and down direction;

[0009] A first driving component, the first driving component including a seat body installed in the installation hole, a rotating shaft rotatably connected to the seat body, there being a gap between the seat body and the installation hole, and the grinding wheel being connected to the rotating shaft;

[0010] Fine adjustment mechanism, the fine adjustment mechanism includes at least three adjustment components spaced circumferentially along the mounting hole, each adjustment component being connected between the fixed seat and the seat body and being used to adjust the downward displacement at the position corresponding to the first drive component and this adjustment component.

[0011] As a further improved technical solution of the present invention, the adjustment component includes a driving member, the driving member feeds longitudinally, the fixed end of the driving member is connected to the fixed seat, and the driving end is connected to the seat body.

[0012] As a further improved technical solution of the present invention, the adjustment component includes a driving member, the driving member feeds transversely, the fixed end of the driving member is connected to the fixed seat; the adjustment component further includes a first slider connected to the seat body, the first slider has a first inclined surface that cooperates with the driving end of the driving member, and when the driving end feeds transversely towards the seat body, the first slider moves downward.

[0013] As a further improved technical solution of the present invention, the adjustment component further includes a second slider connected to the driving end and cooperating with the first slider, and the second slider has a second inclined surface that cooperates with the first inclined surface.

[0014] As a further improved technical solution of the present invention, the adjustment component further includes a roller disposed between the first inclined surface and the second inclined surface.

[0015] As a further improved technical solution of the present invention, the driving member is a piezoelectric ceramic.

[0016] As a further improved technical solution of the present invention, the grinding wheel feeding device further includes a connecting member, the connecting member includes a first fixing ring fixed to the outside of the seat body, a second fixing ring located on the outer periphery of the first fixing ring and fixed to the fixed seat, and an elastic member connected between the first fixing ring and the second fixing ring.

[0017] As a further improved technical solution of the present invention, the adjustment component is connected between the first fixing ring and the second fixing ring; or the adjustment component is connected between the first fixing ring and the fixed seat.

[0018] As a further improved technical solution of the present invention, the grinding wheel feeding device further includes a column and a second driving component connected between the column and the fixed seat, and the second driving component is used to drive the fixed seat to move up and down.

[0019] To achieve the above-mentioned invention purpose, the present invention also provides a silicon wafer thinning machine, including the above-mentioned grinding wheel feeding device.

[0020] The beneficial effects of the present invention are as follows: In the grinding wheel feeding device of the present invention, the fine adjustment mechanism includes at least three adjustment components that are circumferentially and spaced apart along the mounting hole. The adjustment components are used to adjust the downward displacement at the position corresponding to the first driving component of the adjustment component. During wafer grinding, Z-axis micro-feeding can be performed according to specific requirements, improving the stability of the thinning process, increasing the product yield, improving product quality, and further shortening the thinning process flow. At the same time, by controlling the different downward displacements of multiple adjustment components, high-precision tilting adjustment of the grinding wheel in the X-axis and Y-axis directions can be achieved, enabling adjustment of different thinning thicknesses at the center and edge of the wafer, greatly increasing the flexibility of the thinning process, and improving the precision of wafer grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the grinding wheel feeding device in the first embodiment of the present invention;

[0022] Figure 2 is Figure 1 an exploded view of the fixed seat and the adjustment component in the grinding wheel feeding device therein;

[0023] Figure 3 is Figure 1 a schematic structural diagram of the grinding wheel feeding device shown from another angle;

[0024] Figure 4 is Figure 3 a cross-sectional view taken along the A-A direction in;

[0025] Figure 5 is a schematic structural diagram of the grinding wheel feeding device in the second embodiment of the present invention;

[0026] Figure 6 is Figure 5 a cross-sectional view taken along the B-B direction in;

[0027] Figure 7 is Figure 6 an enlarged view of part C in; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be described in detail below in conjunction with the embodiments shown in the drawings. Please refer to Figures 1 to 7 shown, which is a preferred embodiment of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. For those of ordinary skill in the art, without creative efforts, other embodiments obtained based on these embodiments all fall within the protection scope of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the present invention are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features; in addition, unless otherwise clearly specified and defined, the term "connection" should be understood in a broad sense. For example, connection can be direct connection or indirect connection through an intermediate medium, and can be fixed connection, movable connection, detachable connection or integral connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Please refer Figures 1 - 4 As shown, the grinding wheel feeding device 10 in the first embodiment of the present invention is used to drive the grinding wheel 1 to press downwards to grind and thin the silicon wafer located on the carrying workpiece.

[0031] The grinding wheel feeding device 10 includes a grinding wheel 1, a fixed seat 2, a first driving component 3 connected to the fixed seat 2 and used to drive the grinding wheel 1 to rotate, and a fine adjustment mechanism arranged between the fixed seat 2 and the first driving component 3 to indirectly adjust the downward movement amount of the grinding wheel 1.

[0032] The first driving component 3 can adopt any existing spindle as long as it can drive the grinding wheel 1 to rotate. Preferably, the first driving component 3 adopts an air-bearing spindle to achieve ultra-precision grinding. The specific structure of the air-bearing spindle can follow the existing structure of the air-bearing spindle. At the same time, it should be noted that the specific structure inside the first driving component 3 is not shown in detail in the accompanying drawings of the present invention. The specific structure inside the first driving component 3 can follow the first driving component 3 in the prior art, and thus will not be elaborated here.

[0033] Specifically, the first driving component 3 includes a seat body 31 and a first motor arranged inside the seat body 31. The grinding wheel 1 is connected to the rotating shaft 32 of the first motor. When the first motor drives the rotating shaft 32 to rotate, it can drive the grinding wheel 1 to rotate to grind and thin the silicon wafer located on the carrying workpiece.

[0034] The fixed seat 2 has an installation hole 21 penetrating in the up and down direction. The first driving component 3 is installed in the installation hole 21, and there is a gap between the first driving component 3 and the installation hole 21, that is, there is a gap between the seat body 31 and the installation hole 21, so as to provide a certain horizontal movement space for the first driving component 3.

[0035] The fine-tuning mechanism includes at least three adjusting components 4 that are circumferentially and spaced apart along the mounting hole 21. Each adjusting component 4 is connected between the fixed seat 2 and the seat body 31, and the adjusting component 4 is used to adjust the downward displacement amount at the position corresponding to the first driving component 3. In the grinding wheel feeding device 10 of the present invention, during wafer grinding, the downward feeding accuracy of the grinding wheel feeding device 10 can be improved, and the downward displacement amounts of the multiple adjusting components 4 can be controlled to be the same, so that micro-feeding in the Z-axis direction can be performed according to specific requirements. The primary micro-feeding amount of the grinding wheel 1 can be less than 100 nm, improving the stability of the thinning process, increasing the product yield, improving the product quality, and further shortening the thinning process flow. At the same time, by controlling the different downward displacement amounts of the multiple adjusting components 4, high-precision tilting adjustment of the grinding wheel 1 in the X-axis and Y-axis directions can be achieved, enabling adjustment of different thinning thicknesses at the center and edge of the wafer, greatly increasing the flexibility of the thinning process, and improving the grinding accuracy of the wafer.

[0036] In a specific embodiment, the fine-tuning mechanism includes three adjusting components 4, and the three adjusting components 4 are evenly distributed in the circumferential direction of the mounting hole 21, and the tilting angle of the grinding wheel 1 is adjusted by the principle of three-point determination of a plane. Of course, this is not limited thereto. In other embodiments, four or more adjusting components 4 can also be provided to adjust the tilting angle of the grinding wheel 1.

[0037] Further, in this embodiment, each adjusting component 4 includes a driving member 41. The driving member 41 feeds longitudinally. The fixed end 411 of the driving member 41 is connected to the fixed seat 2, and the driving end 412 is connected to the seat body 31. When the driving member 41 is activated, the driving end 412 of the driving member 41 moves in the up and down direction to directly drive the first driving component 3 to move in the up and down direction, indirectly driving the grinding wheel 1 to move in the up and down direction to achieve micro-feeding of the grinding wheel 1.

[0038] It can be understood that the above-mentioned longitudinal direction refers to the up and down direction.

[0039] Specifically, the fixed end 411 is directly connected and fixed to the lower side surface of the fixed seat 2, and the driving end 412 protrudes downward and is connected to the seat body 31. The driving member 41 is connected from the lower side of the fixed seat 2 to the seat body 31, which can prevent the structure on the seat body 31 connected to the driving member 41 from interfering with the mounting hole 21 and affecting the downward displacement amount of the seat body 31.

[0040] In a specific embodiment, the driving member 41 is a piezoelectric ceramic, which is arranged to longitudinally expand and contract with the change of the applied voltage. At this time, the fixed end 411 and the driving end 412 are the opposite ends of the piezoelectric ceramic, which can further improve the downward feeding accuracy of the grinding wheel feeding device 10, enhance the stability of the thinning process, improve the product quality, and further shorten the thinning process flow. Of course, it is not limited thereto, and the driving member 41 can also be arranged as other linear driving structures, such as a structure in which a roller screw is matched with a guide rail pair.

[0041] Further, the grinding wheel feeding device 10 further includes a connecting member 5 connecting the fixed seat 2 and the seat body 31. The connecting member 5 includes a first fixing ring 51 fixed to the outside of the seat body 31, a second fixing ring 52 located on the outer periphery of the first fixing ring 51 and fixed to the fixed seat 2, and an elastic member 53 connected between the first fixing ring 51 and the second fixing ring 52. The stability of the connection between the seat body 31 and the fixed seat 2 is enhanced. It can be known that when the fine adjustment mechanism drives the seat body 31 to perform a micro-feed, the elastic member 53 can undergo corresponding deformation, so that the seat body 31 can perform a micro-feed in the Z-axis direction and / or tilt in the X-axis and Y-axis directions.

[0042] Specifically, between the first fixing ring 51 and the seat body 31, and between the second fixing ring 52 and the fixed seat 2, they can be fixedly connected by screws. Of course, it is not limited thereto.

[0043] Further, the elastic member 53 is an annular elastic member, and is connected to the outer periphery of the first fixing ring 51 and the inner periphery of the second fixing ring 52 to enhance the stability of the relative movement between the first fixing ring 51 and the second fixing ring 52.

[0044] At the same time, in the present invention, the specific structural form of the elastic member 53 is not limited, as long as when the fine adjustment mechanism drives the seat body 31 to perform a micro-feed, the elastic member 53 can undergo corresponding deformation and does not interfere with the movement of the seat body 31.

[0045] More preferably, the elastic member 53 is further arranged such that when the seat body 31 is reset, the elastic member 53 can be reset.

[0046] In the embodiment where the driving member 41 feeds longitudinally and has the connecting member 5 as described above, the driving end 412 of the driving member 41 can be set to be fixedly connected to the first fixing ring 51, so as to indirectly connect the driving end 412 to the seat body 31. That is, the adjusting assembly 4 is connected between the fixing seat 2 and the first fixing ring 51, simplifying the structure of the seat body 31, while simplifying the connection structure among the driving member 41, the connecting member 5, and the seat body 31, and realizing the driving of the seat body 31. Of course, this is not the only limit.

[0047] Please refer Figures 5 - 7 As shown, the wheel feed device 10a in the second embodiment of the present invention is different from the first embodiment in that: the driving member 41a feeds transversely, and the adjusting assembly 4a further includes a first slider 42 connected to the seat body 31. The first slider 42 has a first inclined surface 421 that cooperates with the driving end 412a of the driving member 41a. Along the radial direction of the seat body 31 outward, the height of the first inclined surface 421 gradually decreases. When the driving end 412a feeds transversely towards the seat body 31, the driving end 412a moves to a higher position of the first inclined surface 421, driving the first slider 42 to move downward, and driving the seat body 31 to move downward. That is, the transverse movement of the driving member 41a is converted into the longitudinal movement of the seat body 31. At the same time, the high-precision movement of the seat body 31 in the longitudinal direction can be realized through the transverse movement of the driving member 41a, thereby further improving the downward feed accuracy of the wheel feed device 10a.

[0048] It can be known that the specific slope of the first inclined surface 421 can be adjusted according to the requirement of the one-time micro feed amount of the grinding wheel 1.

[0049] Further, the adjusting assembly 4a further includes a second slider 43 connected to the driving end 412a and cooperating with the first slider 42. The second slider 43 has a second inclined surface 431 that cooperates with the first inclined surface 421. When the driving end 412a feeds transversely towards the seat body 31, the second inclined surface 431 and the first inclined surface 421 move relative to each other, and the first slider 42 moves downward, driving the seat body 31 to move downward.

[0050] Further, the adjusting assembly 4a further includes a roller 44 disposed between the first inclined surface 421 and the second inclined surface 431, reducing the friction between the first inclined surface 421 and the second inclined surface 431, and being more conducive to the relative movement between the first inclined surface 421 and the second inclined surface 431.

[0051] Specifically, the first slider 42 is disposed on the first fixed ring 51, and the fixed end 411a of the driving member 41a is fixedly connected to the second fixed ring 52 to indirectly connect the fixed end 411a to the fixed seat 2. That is, the adjusting assembly 4a is connected between the first fixed ring 51 and the second fixed ring 52, so that the fixed end 411a is relatively fixed to the fixed seat 2, and the first slider 42 is relatively fixed to the seat body 31. The connection between the adjusting assembly 4a and the fixed seat 2 and the seat body 31 is simplified.

[0052] Except for the above differences, the second embodiment is the same as the first embodiment, and thus will not be elaborated herein.

[0053] Further, please refer Figure 1 As shown, the grinding wheel feeding devices 10, 10a further include a column 6 and a second driving assembly 7 connected between the column 6 and the fixed seat 2. The second driving assembly 7 is used to drive the fixed seat 2 to move up and down. In the rough grinding stage of silicon wafer grinding, the second driving assembly 7 drives the fixed seat 2 to move downward, driving the grinding wheel 1 to press down for rough grinding of the silicon wafer. In the fine grinding stage of silicon wafer grinding, the fine adjustment mechanism is used to make the grinding wheel 1 perform a micro-feed in the Z-axis according to specific requirements to avoid micro-cracks on the silicon wafer. At the same time, according to the thinning state of the silicon wafer, the fine adjustment mechanism dynamically adjusts the tilt angle of the grinding wheel 1 to achieve high-precision tilt adjustment of the grinding wheel 1, which can realize the adjustment of different thinning thicknesses of the center and edge of the silicon wafer, greatly increasing the flexibility of the thinning process and improving the precision of silicon wafer grinding.

[0054] Specifically, the second driving assembly 7 includes a second motor 71 fixed on the column 6, a lead screw 72 connected to the second motor 71 and extending in the up and down direction, a nut 73 fixed on the fixed seat 2 and threadedly engaged with the lead screw 72, guide rails 74 disposed on the fixed seat 2 and on opposite sides of the lead screw 72, and guide blocks 75 disposed on the fixed seat 2 and engaged with the guide rails 74. The guide rails 74 extend in the up and down direction. When the second motor 71 starts to drive the lead screw 72 to rotate, the guide blocks 75 move up and down along the guide rails 74 to limit the rotation of the fixed seat 2, so that the nut 73 can only move up and down relative to the lead screw 72, driving the fixed seat 2 to move up and down.

[0055] Further, the present invention also provides a silicon wafer thinning machine, which includes the above-mentioned grinding wheel feeding devices 10, 10a.

[0056] The structures of the grinding wheel feeding devices 10, 10a are as described above, and thus will not be elaborated herein.

[0057] In summary, for the grinding wheel feeding devices 10 and 10a in the present invention, the fine adjustment mechanism includes at least three adjustment components 4 and 4a that are circumferentially and spaced apart along the mounting hole 21. The adjustment components 4 and 4a are used to adjust the downward displacement amount at the position corresponding to the first driving component 3 and the adjustment component 4 or 4a. During wafer grinding, micro-feed in the Z-axis direction can be performed according to specific requirements, improving the stability of the thinning process, increasing the product yield, improving the product quality, and further shortening the thinning process flow. At the same time, by controlling the different downward displacement amounts of the plurality of adjustment components 4 and 4a, high-precision tilting adjustment of the grinding wheel 1 in the X-axis and Y-axis directions can be achieved, enabling adjustment of different thinning thicknesses for the center and edge of the wafer, greatly increasing the flexibility of the thinning process, and improving the precision of wafer grinding.

[0058] It should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0059] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not used to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A grinding wheel feeding device, characterized in that: Comprising: A grinding wheel; A fixed seat having a mounting hole penetrating therethrough in the vertical direction; A first driving assembly including a seat body mounted in the mounting hole and a rotating shaft rotatably connected to the seat body, there being a gap between the seat body and the mounting hole, and the grinding wheel being connected to the rotating shaft; A fine adjustment mechanism including at least three adjustment components circumferentially spaced apart along the mounting hole, each adjustment component being connected between the fixed seat and the seat body and being used to adjust the downward displacement at the position corresponding to the first driving assembly where the adjustment component is located; A connecting member including a first fixing ring fixed to the outer periphery of the seat body, a second fixing ring located on the outer periphery of the first fixing ring and fixed to the fixed seat, and an annular elastic member connected between the first fixing ring and the second fixing ring, the annular elastic member being connected to the outer periphery of the first fixing ring and the inner periphery of the second fixing ring; The adjustment component is connected between the first fixing ring and the second fixing ring; or the adjustment component is connected between the first fixing ring and the fixed seat.

2. The grinding wheel feeding device according to claim 1, wherein: When the adjustment component is connected between the first fixing ring and the fixed seat, the adjustment component includes a driving member that feeds longitudinally, the fixed end of the driving member being connected to the fixed seat and the driving end being connected to the first fixing ring.

3. The grinding wheel feeding device according to claim 1, characterized in that: When the adjustment component is connected between the first fixing ring and the second fixing ring, the adjustment component includes a driving member that feeds transversely, the fixed end of the driving member being connected to the second fixing ring; the adjustment component further includes a first slider connected to the first fixing ring, the first slider having a first inclined surface that cooperates with the driving end of the driving member, and when the driving end feeds transversely towards the seat body, the first slider moves downward.

4. The grinding wheel feeding device according to claim 3, wherein: The adjustment component further includes a second slider connected to the driving end and cooperating with the first slider, the second slider having a second inclined surface that cooperates with the first inclined surface.

5. The grinding wheel feeding device according to claim 4, characterized in that: The adjustment component further includes a roller provided between the first inclined surface and the second inclined surface.

6. The grinding wheel feeding device according to claim 2 or 3, characterized in that: The driving member is a piezoelectric ceramic.

7. The grinding wheel feeding device according to claim 1, wherein: The grinding wheel feeding device further includes a column and a second driving assembly connected between the column and the fixed seat, the second driving assembly being used to drive the fixed seat to move up and down.

8. A silicon wafer thinning machine, characterized in that: The silicon wafer thinning machine includes the grinding wheel feeding device according to any one of claims 1-7.

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