Wafer single-side polishing device

Abstract

The invention discloses a wafer single-side polishing device, which relates to the technical field of wafer polishing and comprises a polishing disc assembly, an inner gear ring assembly, a central gear assembly and a polishing head assembly. The polishing disc assembly comprises a first motor and a polishing disc, and the first motor is in transmission connection with the polishing disc. The inner gear ring assembly comprises a second motor and an inner gear ring, and the second motor is in transmission connection with the inner gear ring. The center gear assembly comprises a third motor and a center gear, and the third motor is in transmission connection with the center gear. The polishing head assembly comprises a suction cup and a planetary gear. The sucker is located on the side, away from the polishing disc, of the wafer and used for sucking the wafer. The planetary gear and the suction cup are circumferentially limited so as to drive the suction cup to rotate. The planetary gear is simultaneously engaged with the ring gear and the sun gear to displace and rotate under the drive of the ring gear and the sun gear. Compared with the prior art, the wafer single-face polishing device can achieve accurate control over the grinding amount while the polishing efficiency and the polishing uniformity are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of wafer polishing, and in particular to a wafer single-side polishing device. Background Art

[0002] For single-sided polishing of wafers, there are mainly the following technical routes: 1) The wafer does not move, and the polishing plate rotates in place; 2) The polishing plate does not move, and the wafer rotates in place; 3) The wafer rotates in place, and the polishing plate rotates in place.

[0003] For the first polishing method, due to the singleness of the relative movement direction, there is a large difference in the grinding amount on the inner and outer sides of the wafer. For the second polishing method, the linear speed of the wafer rotation is small, resulting in low polishing efficiency. For the third polishing method, although the polishing efficiency and polishing uniformity are taken into account, the grinding amount cannot be accurately controlled. Summary of the invention

[0004] The purpose of the present invention is to provide a single-side wafer polishing device to solve the problems existing in the above-mentioned related technologies, and to achieve precise control of the grinding amount while ensuring the polishing efficiency and polishing uniformity.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The invention discloses a wafer single-side polishing device, comprising:

[0007] The polishing disc assembly comprises a motor 1 and a polishing disc, wherein the motor 1 is drivingly connected to the polishing disc;

[0008] An inner gear ring assembly, comprising a second motor and an inner gear ring, wherein the second motor is drivingly connected to the inner gear ring, and the inner gear ring is concentrically arranged with the polishing disc;

[0009] A central gear assembly, comprising a motor three and a central gear, wherein the motor three is drivingly connected to the central gear, and the central gear is concentrically arranged with the polishing disc;

[0010] The polishing head assembly includes a suction cup and a planetary gear; the suction cup is located on the side of the wafer away from the polishing disc and is used to adsorb the wafer; the planetary gear is circumferentially limited with the suction cup to drive the suction cup to rotate; the planetary gear is simultaneously meshed with the inner gear ring and the central gear to shift and rotate under the drive of the inner gear ring and the central gear.

[0011] Preferably, the planetary gear has a central through hole, and the suction cup is located in the central through hole; the polishing head assembly also includes a pressure plate and a guide pin, the pressure plate is located above the planetary gear and fixedly connected to the suction cup; the guide pin passes through the pressure plate vertically, and the lower end of the guide pin is fixedly connected to the planetary gear.

[0012] Preferably, the polishing head assembly further includes a column, a spring, a sliding disk, and a limiting disk; the lower end of the column is fixedly connected to the pressing disk, the spring and the sliding disk are sleeved outside the column, and the spring is located between the pressing disk and the sliding disk; the limiting disk is fixedly connected to the column and is used to limit the extreme position when the sliding disk slides upward; the sliding disk is connected to the guide pin;

[0013] The distance between the pressing disk and the polishing disk is greater than the thickness of the planetary gear, so that the planetary gear can contact and separate from the polishing disk as the length of the spring changes.

[0014] Preferably, the polishing head assembly further includes a connecting member and a connecting disk. The upper end of the connecting member is fixedly connected to the sliding disk, the lower end of the connecting member is fixedly connected to the connecting disk, and the connecting disk is fixedly connected to the upper end of the guide pin to realize the indirect connection between the sliding disk and the guide pin.

[0015] Preferably, the connecting member is a sleeve, and the spring is located inside the sleeve.

[0016] Preferably, the polishing head assembly further includes a counterweight, and the counterweight is fixedly connected to the limiting disk.

[0017] Preferably, the rotation speed range of the polishing disk is 0 - 50 revolutions per minute.

[0018] Preferably, the rotation speed range of the internal gear ring is 0 - 50 revolutions per minute.

[0019] Preferably, the rotation speed range of the central gear is 0 - 100 revolutions per minute.

[0020] Preferably, the pressure applied by the polishing head assembly to the wafer ranges from 0.1 to 10 Newtons per square centimeter.

[0021] The present invention has achieved the following technical effects compared with the related art:

[0022] During the wafer polishing process, by adjusting the rotation speeds of the second motor and the third motor, the linear velocity ratio between the internal gear ring and the central gear can be adjusted, thereby realizing precise control of the grinding amount and improving the polishing quality. Since the wafer rotates around the central gear while revolving, the slope phenomenon of the wafer being thinner at the outer edge and thicker at the inner edge can be avoided.

[0023] In the preferred solution of the present invention, when the planetary gear contacts the polishing disk, the planetary gear can press down the polishing disk in the area around the wafer to avoid excessive grinding of the edge part of the wafer.

[0024] In a preferred embodiment of the present invention, by adjusting the compression amount of the spring, the normal pressure during the wafer grinding process can be adjusted, thereby enabling more precise control of the grinding amount per unit time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 It is a schematic diagram of a wafer single-sided polishing device according to an embodiment of the present invention;

[0027] Figure 2 is Figure 1 a schematic diagram of the local structure in the top view direction;

[0028] Figure 3 is the trajectory of the wafer edge and the wafer center relative to the polishing disc Figure 1 ;

[0029] Figure 4 is the trajectory of the wafer edge and the wafer center relative to the polishing disc Figure 2 .

[0030] In the figure: 1 - wafer; 2 - motor one; 3 - polishing disc; 4 - motor two; 5 - internal gear ring; 6 - motor three; 7 - central gear; 8 - suction cup; 9 - planetary gear; 10 - pressure plate; 11 - guide pin; 12 - column; 13 - spring; 14 - sliding disc; 15 - limit disc; 16 - connecting piece; 17 - connecting disc; 18 - counterweight. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] The object of the present invention is to provide a wafer single-sided polishing device to solve the problems existing in the above-mentioned related technologies, and to achieve precise control of the grinding amount while ensuring the polishing efficiency and polishing uniformity.

[0033] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0034] Reference Figure 1 , Figure 2 This embodiment provides a single-side wafer polishing device, including a polishing disk assembly, an inner gear ring assembly, a central gear assembly and a polishing head assembly.

[0035] The polishing disc assembly includes a motor 2 and a polishing disc 3, and the motor 2 is transmission-connected to the polishing disc 3.

[0036] The inner gear ring assembly comprises a second motor 4 and an inner gear ring 5 . The second motor 4 is transmission-connected to the inner gear ring 5 . The inner gear ring 5 is concentrically arranged with the polishing disc 3 .

[0037] The central gear assembly includes a motor 3 6 and a central gear 7 . The motor 3 6 is transmission-connected to the central gear 7 . The central gear 7 is concentrically arranged with the polishing disc 3 .

[0038] The polishing head assembly includes a suction cup 8 and a planetary gear 9. The suction cup 8 is located on the side of the wafer 1 away from the polishing plate 3, and is used to absorb the wafer 1. The planetary gear 9 is circumferentially limited with the suction cup 8 to drive the suction cup 8 to rotate. The planetary gear 9 is simultaneously engaged with the inner gear ring 5 and the central gear 7 to shift and rotate under the drive of the inner gear ring 5 and the central gear 7.

[0039] The working principle of the wafer single-side polishing device in this embodiment is as follows:

[0040] The suction cup 8 carries the wafer 1 by vacuum adsorption, and then contacts one side surface of the wafer 1 with the polishing disc 3, and starts the motor 1 2 to polish the wafer 1. During the polishing process of the wafer 1, by adjusting the rotation speed of the motor 2 4 and the motor 3 6, the ratio of the linear speed of the inner gear ring 5 and the central gear 7 can be adjusted, so as to achieve precise control of the grinding amount and improve the polishing quality. Since the wafer 1 rotates while revolving around the central gear 7, the slope phenomenon of the wafer 1 being thin outside and thick inside can be avoided.

[0041] The ratio of the linear velocities of the inner gear ring 5 and the central gear 7 can be converted into the ratio of their angular velocities, and the angular velocities of the two can be measured respectively by the corresponding magnetic encoder to establish real-time monitoring of the ratio of the linear velocities of the inner gear ring 5 and the central gear 7. During actual processing, the staff or the control computer can adjust the speed of the motor 2 and the motor 3 according to the real-time monitoring results to keep the ratio of the linear velocities of the inner gear ring 5 and the central gear 7 within a certain range.

[0042] It should be noted that in this embodiment, during the grinding process, the three speed variables of the rotation speed of the polishing disc 3, the rotation speed of the inner ring 5 and the rotation speed of the center gear 7 can be adjusted, and the three speed variables have multiple combinations to achieve precise control of the grinding amount.

[0043] In order to more clearly show the influence of the ratio of the linear speed of the inner gear 5 to the central gear 7 on the grinding trajectory, Figure 3The trajectory diagram when the linear velocity ratio is a certain value is shown. Figure 4 The trajectory diagram when the linear velocity ratio is another value is shown.

[0044] Figure 3 and Figure 4 In, the circular line at the central position is the trajectory of the center of the wafer 1 ( Figure 3 It is a dotted line in, Figure 4 It is a thick line in), and the other line (non-circular) is the trajectory of a certain position on the edge of the wafer 1. Obviously, when the linear velocity ratio changes, the trajectory of the edge of the wafer 1 changes, so that by designing the trajectory of the edge of the wafer 1, the grinding amount of the edge of the wafer 1 can be accurately controlled.

[0045] As a possible example, in this embodiment, the planetary gear 9 has a central through hole, and the suction cup 8 is located in the central through hole. The polishing head assembly further includes a pressure plate 10 and a guide pin 11. The pressure plate 10 is located above the planetary gear 9 and is fixedly connected to the suction cup 8. The guide pin 11 passes through the pressure plate 10 vertically, and the lower end of the guide pin 11 is fixedly connected to the planetary gear 9.

[0046] In this embodiment, the circumferential limit between the pressure plate 10 and the planetary gear 9 is realized through the guide pin 11, and further the circumferential limit between the suction cup 8 fixedly connected to the pressure plate 10 and the planetary gear 9 is realized, that is, the same-speed rotation of the suction cup 8 and the planetary gear 9 is realized. According to different actual needs, those skilled in the art can also select other circumferential limiting methods, such as realizing circumferential limitation by welding, bonding and other methods.

[0047] As a possible example, in this embodiment, the polishing head assembly further includes a column 12, a spring 13, a sliding disk 14 and a limit disk 15. The lower end of the column 12 is fixedly connected to the pressure plate 10. The spring 13 and the sliding disk 14 are sleeved outside the column 12, and the spring 13 is located between the pressure plate 10 and the sliding disk 14. The limit disk 15 is fixedly connected to the column 12 and is used to limit the extreme position when the sliding disk 14 slides upward. The sliding disk 14 is connected to the guide pin 11.

[0048] The distance between the pressure plate 10 and the polishing disc 3 is greater than the thickness of the planetary gear 9, so that the planetary gear 9 can contact and separate from the polishing disc 3 as the length of the spring 13 changes.

[0049] When the planetary gear 9 contacts the polishing disc 3, the planetary gear 9 can press down the polishing disc 3 in the surrounding area of the wafer 1 to a certain extent, avoiding excessive grinding of the edge part of the wafer 1. When the spring 13 is compressed, since the sliding disk 14, the guide pin 11 and the planetary gear 9 are connected as an integral structure, a part of the gravity of this integral structure is transmitted to the pressure plate 10 through the spring 13, and then transmitted to the lower suction cup 8 and the wafer 1, realizing an increase in the normal pressure during the grinding process of the wafer 1 to improve the grinding efficiency.

[0050] By replacing the springs 13 with different initial lengths, the compression amount of the spring 13 can be adjusted, thereby adjusting the normal pressure during the grinding process of the wafer 1, so as to facilitate more precise control of the grinding amount per unit time.

[0051] Combining rotational speed control and pressure control can accurately control the TTV (Total Thickness Variation) and surface profile of the polished wafer 1, improve the polishing quality of the wafer 1, and meet the requirements of high-precision polishing.

[0052] During actual processing, according to the detection results of the wafer size after each processing, the rotational speed control and pressure control are adjusted to maintain the relative constancy of the polishing removal rate.

[0053] After the planetary gear 9 rises to a certain height, it abuts against the limit of the pressure plate 10, thereby restricting the height of the planetary gear 9 through the pressure plate 10 to ensure that the planetary gear 9 always remains in mesh with the internal gear ring 5 and the central gear 7 at the same time.

[0054] By fixedly connecting the pressure plate 10 to the suction cup 8, the center of gravity is lowered. Combining the mutual limitation between the pressure plate 10 and the lower planetary gear 9, the angle of the suction cup 8 is maintained as horizontal as possible, thereby ensuring that the lower wafer 1 receives uniform downward pressure and ensuring the uniformity of the grinding effect of the wafer 1.

[0055] As a possible example, in this embodiment, the polishing head assembly further includes a connecting member 16 and a connecting plate 17. The upper end of the connecting member 16 is fixedly connected to the sliding plate 14, the lower end of the connecting member 16 is fixedly connected to the connecting plate 17, and the connecting plate 17 is fixedly connected to the upper end of the guide pin 11 to achieve the indirect connection between the sliding plate 14 and the guide pin 11.

[0056] In this embodiment, instead of directly connecting the sliding plate 14 to the upper end of the guide pin 11, the connecting member 16 and the connecting plate 17 are added. Since the sliding plate 14, the connecting member 16, the connecting plate 17, the guide pin 11, and the planetary gear 9 are connected as an integral structure, the setting of the connecting member 16 and the connecting plate 17 makes the integral structure have a greater weight, thereby expanding the adjustment range of the grinding pressure of the wafer 1.

[0057] As a possible example, in this embodiment, the connecting member 16 is a sleeve, and the spring 13 is located inside the sleeve. The diameter of the sleeve is smaller than that of the connecting plate 17, making the weight distribution of the overall structure more concentrated at the central position, and the setting of the connecting plate 17 makes the weight distribution of the overall structure more concentrated at the lower part, thereby making the overall structure more stable and not prone to skew.

[0058] Exemplarily, the limit disk 15 and the column 12 are detachably connected, and the sliding disk 14 and the sleeve are detachably connected to facilitate the replacement of the spring 13. The detachable connection here can be flexibly selected, such as a threaded fit or connection by fasteners such as screws.

[0059] As a possible example, in this embodiment, the polishing head assembly further includes a counterweight 18, and the counterweight 18 is fixedly connected to the limit disk 15. By providing the counterweight 18, the adjustment range of the grinding pressure of the wafer 1 can be further expanded, so as to meet the requirements of different grinding processes.

[0060] As a possible example, in this embodiment, the rotation speed range of the polishing disk 3 is 0 to 50 revolutions per minute, preferably 20 revolutions per minute. The rotation speed range of the internal gear ring 5 is 0 to 50 revolutions per minute, preferably 5 revolutions per minute. The rotation speed range of the central gear 7 is 0 to 100 revolutions per minute, preferably 15 revolutions per minute.

[0061] The first motor 2, the second motor 4, and the third motor 6 are preferably reduction motors configured with speed reducers to achieve stable operation at low speeds.

[0062] As a possible example, in this embodiment, the pressure applied by the polishing head assembly to the wafer 1 ranges from 0.1 to 10 Newtons per square centimeter, preferably 1 Newton per square centimeter.

[0063] Specific examples are used in the present invention to illustrate the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A wafer single-side polishing device, characterized in that: include: The polishing disc assembly comprises a motor 1 and a polishing disc, wherein the motor 1 is drivingly connected to the polishing disc; An inner gear ring assembly, comprising a second motor and an inner gear ring, wherein the second motor is drivingly connected to the inner gear ring, and the inner gear ring is concentrically arranged with the polishing disc; A central gear assembly, comprising a motor three and a central gear, wherein the motor three is drivingly connected to the central gear, and the central gear is concentrically arranged with the polishing disc; The polishing head assembly includes a suction cup and a planetary gear; the suction cup is located on the side of the wafer away from the polishing disc and is used to adsorb the wafer; the planetary gear is circumferentially limited with the suction cup to drive the suction cup to rotate; the planetary gear is simultaneously meshed with the inner gear ring and the central gear to shift and rotate under the drive of the inner gear ring and the central gear.

2. The wafer single-side polishing device according to claim 1, characterized in that: The planetary gear has a central through hole, and the suction cup is located in the central through hole; the polishing head assembly also includes a pressure plate and a guide pin, the pressure plate is located above the planetary gear and fixedly connected to the suction cup; the guide pin passes through the pressure plate vertically, and the lower end of the guide pin is fixedly connected to the planetary gear.

3. The wafer single-side polishing device according to claim 2, characterized in that: The polishing head assembly also includes a column, a spring, a sliding plate and a limit plate; the lower end of the column is fixedly connected to the pressure plate, the spring and the sliding plate are sleeved on the outside of the column, and the spring is located between the pressure plate and the sliding plate; the limit plate is fixedly connected to the column to limit the extreme position of the sliding plate when sliding upward; the sliding plate is connected to the guide pin; The distance between the pressure plate and the polishing plate is greater than the thickness of the planetary gear, so that the planetary gear can contact and separate from the polishing plate as the length of the spring changes.

4. The wafer single-side polishing device according to claim 3, characterized in that: The polishing head assembly also includes a connecting member and a connecting plate, the upper end of the connecting member is fixedly connected to the sliding plate, the lower end of the connecting member is fixedly connected to the connecting plate, and the connecting plate is fixedly connected to the upper end of the guide pin to achieve indirect connection between the sliding plate and the guide pin.

5. The wafer single-side polishing device according to claim 4, characterized in that: The connecting piece is a sleeve, and the spring is located inside the sleeve.

6. The wafer single-side polishing device according to claim 3, characterized in that: The polishing head assembly also includes a counterweight block, and the counterweight block is fixedly connected to the limiting plate.

7. The wafer single-side polishing device according to claim 1, characterized in that: The rotation speed of the polishing disc ranges from 0 to 50 rpm.

8. The wafer single-side polishing device according to claim 1, characterized in that: The rotation speed range of the inner gear ring is 0 to 50 rpm.

9. The wafer single-side polishing device according to claim 1, characterized in that: The rotation speed range of the central gear is 0 to 100 rpm.

10. The wafer single-side polishing device according to claim 1, characterized in that: The pressure applied by the polishing head assembly to the wafer ranges from 0.1 to 10 Newtons per square centimeter.

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