Wafer thinning device

Abstract

The invention relates to the technical field of wafer processing, and discloses a wafer thinning device.A Z-axis moving assembly comprises a main shaft mounting frame, and the main shaft mounting frame is arranged on an upper lathe bed support in a sliding mode through three Z-axis sliding tables matched with three Z-axis guide rails; the grinding main shaft assembly is arranged on the Z-axis moving assembly and located in the center of a triangle formed by the three Z-axis guide rails. A Z-axis driving assembly used for driving the main shaft mounting frame to move in the Z-axis direction is arranged on the upper lathe bed support. According to the invention, the Z-axis moving assembly adopts three Z-axis guide rails for positioning and guiding, so that the movement in the Z-axis direction is stable, and the grinding quality of a thinning grinding wheel on a wafer is improved; the center of the turntable is concentric with the center of the lead screw, deflection influence is reduced, grinding is uniform, and rigidity is good; and meanwhile, three-point leveling is selected for the planeness of the thinning main shaft, the planeness of the thinning main shaft can be conveniently, rapidly and efficiently adjusted, and the subsequent machining quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of wafer processing, and in particular to a wafer thinning device. Background Art

[0002] In the semiconductor field, wafer thinning has become relatively mature after years of development, and wafer thinning equipment has become more and more mature. A wafer thinner is a device that uses a grinding wheel to grind the surface of a wafer. It is the most critical post-packaging equipment in the integrated circuit manufacturing process. A wafer thinner, also known as a wafer grinder, is a device specifically used for fine processing of the surface of a semiconductor wafer. It removes one or more layers of material on the surface of the wafer through a grinding process to achieve the purpose of thinning the thickness of the wafer, improving the process adaptability and surface quality of the wafer. During the processing, the wafer to be ground is precisely clamped on the workbench, and its horizontal movement is controlled by the feed axis, while the rotating axis drives the wafer to rotate. The grinding head carries the grinding disc and abrasive. As the grinding disc rotates, the abrasive grinds the surface of the wafer with the assistance of the grinding fluid, thereby achieving a thinning effect.

[0003] During the grinding process of the wafer, since the wafer needs to be ground to a thinner state, jagged edges will appear on the edge of the wafer. Currently, the chipped edges of the wafer cannot be removed after grinding, so that during the polishing process, the chipped edges are easy to fall off, leaving tiny crystal slag on the surface of the wafer. The tiny crystal slag will cause the surface of the wafer to be scratched. The deeper scratches on the surface of the wafer are difficult to completely remove after treatment. In addition, during the polishing process, tiny grains will fall off around the scratched surface of the wafer, resulting in the wafer's contaminant process indicators not meeting the standards. Therefore, the quality of wafer processing is poor. At the same time, after a long period of operation, the flatness of the thinning spindle of the wafer thinning machine needs to be adjusted and leveled again. In the existing thinning machine, the flatness adjustment operation of the thinning spindle is relatively cumbersome, the adjustment efficiency is low, and the downtime is long, which affects the processing efficiency. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a wafer thinning device, which solves the problems that the existing thinning machine is prone to damage the wafer surface during grinding, affecting the quality of the final processed wafer; and the secondary leveling operation of the thinning spindle is cumbersome and the downtime is long.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A wafer thinning device comprises a carrier platform assembly and a Z-axis moving assembly arranged above the carrier platform assembly, wherein a grinding spindle assembly for grinding the workpiece on the carrier platform assembly is arranged on the Z-axis moving assembly, wherein the Z-axis moving assembly comprises a spindle mounting frame, wherein the spindle mounting frame is slidably arranged on the upper bed bracket through three Z-axis slides and three Z-axis guide rails, wherein the grinding spindle assembly is arranged on the Z-axis moving assembly and is located at the center position of a triangle formed by the three Z-axis guide rails; a Z-axis driving assembly for driving the spindle mounting frame to move along the Z-axis direction is arranged on the upper bed bracket; the grinding spindle assembly comprises a thinning spindle, a thinning grinding wheel fixedly arranged on the thinning spindle, and a spindle fixing seat fixed to the thinning spindle, wherein the spindle fixing seat is installed on the spindle mounting frame by a three-point positioning method, wherein two positioning points are adjustably connected to the spindle mounting frame through a spindle leveling assembly, and one positioning point is fixedly connected to the spindle mounting frame through a fixing assembly.

[0009] Preferably, the Z-axis drive assembly includes a first drive motor fixedly mounted on an upper bed bracket via a motor mounting seat, the output shaft end of the first drive motor is fixedly connected to a transmission screw, a screw nut seat is transmission-connected to the transmission screw, the screw nut seat is fixedly mounted on the spindle mounting frame, and the center line of the support platform assembly coincides with the center line of the transmission screw.

[0010] Preferably, the grinding spindle assembly further comprises a spindle mounting plate, which is fixedly connected to the spindle fixing seat via a spindle leveling assembly and a fixing assembly respectively, and the spindle mounting plate is also fixedly mounted on the lower end surface of the spindle mounting frame.

[0011] Preferably, the spindle leveling assembly includes a fixing sleeve fixedly connected to the spindle fixing seat and a cylindrical screw sleeve threadedly connected to the spindle mounting plate, an intermediate stud is threadedly connected between the cylindrical screw sleeve and the fixing sleeve, an adjusting nut is threadedly connected to the lower part of the cylindrical screw sleeve, and the adjusting nut presses against the step at the lower part of the cylindrical screw sleeve to lock and fix the cylindrical screw sleeve.

[0012] Preferably, the lower portion of the upper bed support is fixedly connected to a lower bed support, the bearing platform assembly is fixedly arranged on the lower bed support, and the upper bed support and the lower bed support are both designed to be integrated.

[0013] Preferably, the supporting platform assembly includes a workbench and a ceramic suction cup fixedly arranged on the workbench, the workbench is arranged on the supporting platform base through a DD motor transmission, the supporting platform base is fixedly connected to the lower bed bracket, the lower end surface of the supporting platform base is used for providing negative pressure suction to the ceramic suction cup on the workbench through an air slip ring, and the lower end surface of the air slip ring is transmission-connected to a second drive motor.

[0014] Preferably, a slip ring protective cover is provided on the outer cover of the air slip ring at the lower end surface of the support platform base, a sealing ring is sleeved on the outer side of the slip ring core of the air slip ring, a gas channel connected to a ceramic suction cup is provided on the slip ring core of the air slip ring, a negative pressure gas nozzle connected to the gas channel is provided on the air slip ring, and sealing ring holes that match the negative pressure gas nozzles one by one are arranged on the sealing ring.

[0015] (III) Beneficial effects

[0016] The present invention has the following beneficial effects:

[0017] The wafer thinning device, through the triangularly arranged Z-axis slide and Z-axis guide rail, can effectively ensure the stability and high rigidity of the Z-axis moving component in driving the grinding spindle component to move, so that when the thinning grinding wheel on the thinning spindle performs thinning processing on the workpiece on the carrier assembly, it can effectively avoid the shaking of the Z-axis caused by the traditional Z-axis being driven up and down by a single guide rail through a lead screw, resulting in uneven grinding of the workpiece and increased risk of breakage of the workpiece, thereby improving the processing quality; the thinning spindle and the thinning grinding wheel thereon are installed by adopting a three-point positioning method, so that when the flatness of the thinning spindle needs to be adjusted later, the spindle leveling components at the two positioning points can be used to quickly adjust the flatness of the thinning spindle, thereby shortening the downtime and improving the subsequent processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of the main view of the present invention;

[0019] Figure 2 This is a schematic diagram of the Z-axis portion of the split structure of the present invention;

[0020] Figure 3 This is a schematic diagram of the overall structure of the Z-axis moving assembly of the present invention;

[0021] Figure 4 This is a schematic diagram of the split structure of the Z-axis moving assembly and the grinding spindle assembly of the present invention;

[0022] Figure 5 This is a schematic diagram of the structure of the spindle leveling assembly of the present invention;

[0023] Figure 6 It is a schematic diagram of the layout structure of the fixing assembly and the spindle leveling assembly of the present invention;

[0024] Figure 7 It is a schematic diagram of the internal structure of the carrier platform assembly of the present invention;

[0025] Figure 8 This is a schematic diagram of the overall structure of the sliding ring core and the sealing ring of the present invention;

[0026] Fig. 9It is a schematic diagram comparing the Z-axis moving assembly driving the grinding spindle assembly of the present invention with the prior art.

[0027] In the figure: 1. upper bed bracket; 2. lower bed bracket; 3. Z-axis drive assembly; 31. first drive motor; 32. motor mounting seat; 33. lead screw nut seat; 34. transmission screw; 4. Z-axis moving assembly; 41. spindle mounting frame; 42. Z-axis slide; 43. Z-axis guide rail; 5. grinding spindle assembly; 51. spindle mounting plate; 52. thinning spindle; 53. thinning grinding wheel; 54. spindle fixing seat; 55. spindle leveling assembly; 551. cylindrical screw sleeve; 552. adjusting nut; 553. intermediate stud; 554. fixing sleeve; 56. fixing assembly; 6. bearing platform assembly; 61. DD motor; 62. workbench; 63. ceramic suction cup; 64. bearing platform base; 65. gas slip ring; 66. slip ring protective cover; 67. second drive motor; 68. sealing ring; 69. gas channel. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figure 1 The present invention provides a technical solution: a wafer thinning device, comprising a carrier platform assembly 6 and a Z-axis moving assembly 4 arranged above the carrier platform assembly 6, a grinding spindle assembly 5 for grinding a workpiece on the carrier platform assembly 6 arranged on the Z-axis moving assembly 4, the Z-axis moving assembly 4 comprising a spindle mounting frame 41, the spindle mounting frame 41 is slidably arranged on an upper bed support 1 through three Z-axis slides 42 and three Z-axis guide rails 43, the grinding spindle assembly 5 is arranged on the Z-axis moving assembly 4 and is located in a triangle formed by the three Z-axis guide rails 43 Center position; a Z-axis drive assembly 3 is arranged on the upper bed bracket 1 to drive the spindle mounting frame 41 to move along the Z-axis direction; the grinding spindle assembly 5 includes a thinning spindle 52, a thinning grinding wheel 53 fixedly arranged on the thinning spindle 52, and a spindle fixing seat 54 fixed to the thinning spindle 52, the spindle fixing seat 54 is installed on the spindle mounting frame 41 by a three-point positioning method, two of which are adjustably connected to the spindle mounting frame 41 through a spindle leveling assembly 55, and one positioning point is fixedly connected to the spindle mounting frame 41 through a fixing assembly 56.

[0030] The present invention, through the triangularly arranged Z-axis slide 42 and Z-axis guide rail 43, can effectively ensure the stability and high rigidity of the Z-axis moving component 4 in driving the grinding spindle component 5 to move, so that when the thinning grinding wheel 53 on the thinning spindle 52 performs thinning processing on the workpiece on the carrier platform component 6, it can effectively avoid the situation that the traditional Z-axis is driven up and down by a single guide rail through a lead screw, causing shaking in the Z-axis, resulting in uneven grinding of the workpiece and increasing the risk of breakage of the workpiece, thereby improving the processing quality; the thinning spindle 52 and the thinning grinding wheel 53 thereon are installed by adopting a three-point positioning method, so that when the flatness of the thinning spindle 52 needs to be adjusted later, the spindle leveling components 55 at the two positioning points can be used to quickly adjust the flatness of the thinning spindle 52, thereby shortening the downtime and improving the subsequent processing accuracy.

[0031] Reference Figure 2 and 3 As shown, in this embodiment, the Z-axis drive assembly 3 includes a first drive motor 31 fixedly mounted on the upper bed support 1 through a motor mounting seat 32, and the output shaft end of the first drive motor 31 is fixedly connected to a transmission screw 34, and a screw nut seat 33 is transmission-connected to the transmission screw 34, and the screw nut seat 33 is fixedly mounted on the spindle mounting frame 41, and the center line of the bearing platform assembly 6 is concentric with the center line of the transmission screw 34. The center of the bearing platform assembly 6 is concentric with the center of the transmission screw 34, which reduces the influence of the yaw, so that the thinning grinding wheel 53 on the thinning spindle 52 can be ground evenly and with good rigidity; when the drive screw 34 moves, the nut seat cooperates with the slider to move along the Z-axis guide rail, which is more stable, has high precision and reduces the transmission chain. , which makes the transmission more stable, reduces the transmission chain, and has higher transmission precision, which is conducive to real-time high-precision grinding processing. Refer to Fig. 9 As shown, the Z-axis of the traditional thinning machine is driven up and down by a single guide rail through a lead screw, which may cause shaking in the Z-axis, resulting in uneven grinding of the workpiece and increasing the risk of breakage of the workpiece.

[0032] Reference Figure 4 and 5 As shown, in this embodiment, the grinding spindle assembly 5 also includes a spindle mounting plate 51, which is fixedly connected to the spindle fixing seat 54 through the spindle leveling assembly 55 and the fixing assembly 56, and the spindle mounting plate 51 is also fixedly mounted on the lower end surface of the spindle mounting frame 41. By setting the spindle mounting plate 51, the stability of the installation of the entire thinning spindle 52 and the spindle mounting frame 41 can be ensured, thereby improving the synchronization of the thinning spindle 52 and the spindle mounting frame 41 in the Z-axis direction, improving the rigidity of the moving process, and facilitating the high-precision machining of the workpiece.

[0033] Reference Figure 5 and 6As shown, in this embodiment, the spindle leveling assembly 55 includes a fixing sleeve 554 fixedly connected to the spindle fixing seat 54 and a cylindrical screw sleeve 551 threadedly connected to the spindle mounting plate 51, an intermediate stud 553 is threadedly connected between the cylindrical screw sleeve 551 and the fixing sleeve 554, and an adjusting nut 552 is threadedly connected to the lower part of the cylindrical screw sleeve 551, and the adjusting nut 552 is pressed against the step at the lower part of the cylindrical screw sleeve 551 to lock and fix the cylindrical screw sleeve 551. By setting the cylindrical screw sleeve 551 and the intermediate stud 553, when it is necessary to adjust the flatness of the thinned spindle 52, it is only necessary to release the locking of the cylindrical screw sleeve 551 by the adjusting nut 552, and by rotating the cylindrical screw sleeve 551, the cylindrical screw sleeve 551 cooperates with the adjusting screw to pull the spindle mounting plate 51 upward or push the spindle mounting plate 51 downward, and finally the flatness at the two adjustable positioning points and the flatness of the spindle mounting plate 51 at the fixing assembly 56 meet the expected requirements. After the leveling is completed, the leveling locking is completed by tightening the adjusting nut 552 again. During the adjustment process, the cylindrical screw sleeve 551 moves along the middle stud 553 to drive the adjustment of the spindle mounting plate 51, and the middle stud 553 plays a role of guiding and assisting the adjustment.

[0034] Reference Figure 1 As shown, in this embodiment, the lower part of the upper bed support 1 is fixedly connected to the lower bed support 2, and the bearing platform assembly 6 is fixedly arranged on the lower bed support 2. The upper bed support 1 and the lower bed support 2 are designed to be integrated. The bed support is designed to be integrated and can be made of mineral castings or other materials, and the strength and accuracy can be better guaranteed. The bed support uses materials such as mineral castings. Mineral castings have the characteristics of high precision, high stability and high strength. They also have shock absorption properties, which are beneficial to improving the dynamic stability and processing accuracy of the machine tool and extending the working life.

[0035] Reference Figure 3 and 7As shown, in this embodiment, the bearing platform assembly 6 includes a workbench 62 and a ceramic suction cup 63 fixedly arranged on the workbench 62. The workbench 62 is arranged on the bearing platform base 64 through the transmission of the DD motor 61. The bearing platform base 64 is fixedly connected to the lower bed support 2. The lower end surface of the bearing platform base 64 is used to provide negative pressure suction to the ceramic suction cup 63 on the workbench 62 through the air slip ring 65. The lower end surface of the air slip ring 65 is connected to the second drive motor 67. The ceramic suction cup 63 contains a large number of tiny pores, which can be open or closed, and the pore size is generally micron or submicron. When the external pressure changes, these micropores will absorb or release air, thereby generating suction or thrust. Specifically, when the external pressure decreases, air is sucked into the micropores, forming a negative pressure, causing the suction cup to be adsorbed on the plane surface; when the external pressure increases, the air is released from the micropores, and the suction cup is detached from the surface. The microporous ceramic suction cup 63 has the advantages of high temperature resistance, wear resistance, chemical corrosion resistance, high mechanical strength, easy regeneration and excellent thermal shock resistance. The second drive motor 67 drives the air slip ring 65 to drive the worktable 62 and the ceramic suction cup 63 to rotate, thereby driving the workpiece to rotate for processing and grinding.

[0036] Reference Figure 8 As shown, in this embodiment, the lower end surface of the carrier base 64 is located at the outer cover of the gas slip ring 65 and is provided with a slip ring protective cover 66, the outer sleeve of the slip ring core of the gas slip ring 65 is provided with a sealing ring 68, the slip ring core of the gas slip ring 65 is provided with a gas channel 69 connected to the ceramic suction cup 63, the gas slip ring 65 is provided with a negative pressure gas nozzle connected to the gas channel 69, and the sealing ring 68 is provided with sealing ring 68 holes that match the negative pressure gas nozzles one by one. The provided sealing ring 68 can ensure the sealing performance inside the gas slip ring 65 when the second driving motor 67 drives the slip ring core to rotate; at the same time, due to the arranged sealing ring 68 holes, the slip ring core hole can be aligned with the sealing ring 68 hole during the rotation of the slip ring core, so that the negative pressure gas in the negative pressure gas nozzle enters the workbench 62 and the ceramic suction cup 63 through the gas channel 69 in the inner cavity of the gas slip ring 65, so that the ceramic suction cup 63 generates negative pressure to fix the workpiece. By providing air holes or air grooves of different sizes on the workbench 62 , ceramic suction cups 63 of different sizes can be used to absorb workpieces of various sizes.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions. The sentence "includes an element defined by ... does not exclude the existence of other identical elements in the process, method, article or device including the element".

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wafer thinning device, comprising a carrier assembly and a Z-axis moving assembly arranged above the carrier assembly, wherein a grinding spindle assembly for grinding a workpiece on the carrier assembly is arranged on the Z-axis moving assembly, characterized in that: The Z-axis moving assembly includes a spindle mounting frame, which is slidably arranged on the upper bed bracket through three Z-axis slides and three Z-axis guide rails. The grinding spindle assembly is arranged on the Z-axis moving assembly and is located at the center of the triangle formed by the three Z-axis guide rails; a Z-axis driving assembly for driving the spindle mounting frame to move along the Z-axis direction is arranged on the upper bed bracket; the grinding spindle assembly includes a thinning spindle, a thinning grinding wheel fixedly arranged on the thinning spindle, and a spindle fixing seat fixed to the thinning spindle, and the spindle fixing seat is installed on the spindle mounting frame by a three-point positioning method, wherein two positioning points are adjustably connected to the spindle mounting frame through a spindle leveling assembly, and one positioning point is fixedly connected to the spindle mounting frame through a fixing assembly.

2. A wafer thinning device according to claim 1, characterized in that: The Z-axis drive assembly includes a first drive motor fixedly mounted on an upper bed bracket via a motor mounting seat, a transmission screw being fixedly connected to an output shaft end of the first drive motor, a screw nut seat being transmission-connected to the transmission screw, and a screw nut seat being fixedly mounted on the spindle mounting frame, and a center line of the support platform assembly coincides with a center line of the transmission screw.

3. A wafer thinning device according to claim 1, characterized in that: The grinding spindle assembly also includes a spindle mounting plate, which is fixedly connected to the spindle fixing seat through a spindle leveling assembly and a fixing assembly, and the spindle mounting plate is also fixedly mounted on the lower end surface of the spindle mounting frame.

4. A wafer thinning device according to claim 1 or 3, characterized in that: The spindle leveling assembly includes a fixing sleeve fixedly connected to the spindle fixing seat and a cylindrical screw sleeve threadedly connected to the spindle mounting plate, an intermediate stud is threadedly connected between the cylindrical screw sleeve and the fixing sleeve, an adjusting nut is threadedly connected to the lower part of the cylindrical screw sleeve, and the adjusting nut presses against the step at the lower part of the cylindrical screw sleeve to lock and fix the cylindrical screw sleeve.

5. A wafer thinning device according to claim 4, characterized in that: The lower part of the upper bed support is fixedly connected to the lower bed support, the bearing platform assembly is fixedly arranged on the lower bed support, and the upper bed support and the lower bed support are both designed to be integrated.

6. A wafer thinning device according to claim 4, characterized in that: The support platform assembly includes a workbench and a ceramic suction cup fixedly arranged on the workbench. The workbench is arranged on the support platform base through a DD motor drive. The support platform base is fixedly connected to the lower bed bracket. The lower end surface of the support platform base is used to provide negative pressure suction to the ceramic suction cup on the workbench through an air slip ring. The lower end surface of the air slip ring is transmission-connected to a second drive motor.

7. A wafer thinning device according to claim 6, characterized in that: The lower end surface of the support platform base is located on the outer cover of the air slip ring and is provided with a slip ring protective cover. The outer part of the slip ring core of the air slip ring is sleeved with a sealing ring. The slip ring core of the air slip ring is provided with a gas channel connected to a ceramic suction cup. The air slip ring is connected to a negative pressure gas nozzle connected to the gas channel, and the sealing ring is arranged with sealing ring holes that match the negative pressure gas nozzles one by one.

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