Semiconductor grinding spindle and semiconductor grinding equipment

Abstract

The present invention discloses a semiconductor grinding spindle and semiconductor grinding equipment, including: a support base; a spindle body, which is supported on the support base by a magnetic levitation device, one end of the spindle body is used to set a grinding disc, and the magnetic levitation device at least includes an axial magnetic levitation component and a radial magnetic levitation component, the axial magnetic levitation component is used to provide axial support force for the spindle body, and the radial magnetic levitation component is used to provide radial support force for the spindle body. The present invention constructs a magnetic field between the spindle body and the support base to generate an interaction force, so that the spindle body is in a suspended state, forming a rotating support without mechanical contact, so that the friction loss is small, and because there is no friction, the problem of reduced accuracy due to wear is avoided, and gas is not required as a lubricant, so the pollution problem caused by the introduction of gas can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing equipment, and in particular to a semiconductor grinding spindle and semiconductor grinding equipment. Background Art

[0002] The semiconductor chip grinding process is an important step in the chip manufacturing process. It usually adopts mechanical grinding to grind the wafer using grinding machinery to achieve the required thickness. In this process, the grinding thickness and uniformity need to be controlled to ensure the smooth progress of subsequent processes.

[0003] The spindle of the semiconductor grinding equipment in the prior art is supported on the machine base of the grinding equipment by bearings. During the grinding process, the interaction force is transmitted by mechanical contact, that is, the radial and axial grinding forces are transmitted by the direct force between the spindle and the bearings. This method of transmitting the interaction force by using ordinary bearings has the problem of easy wear of the bearings, and after the bearings are worn, the grinding accuracy of the grinding equipment will be affected.

[0004] There is also a solution in the prior art that uses an air-floating spindle as the spindle of a semiconductor grinding device, that is, replacing the ordinary bearing on the spindle of the semiconductor grinding device with an air bearing (also called an air-floating bearing). An air bearing is a sliding bearing that uses gas (usually air, but it may also be other gases) as a lubricant. Since there is no mechanical contact, the degree of wear is reduced to a minimum, thereby ensuring that the accuracy remains stable. However, the form of the air-floating spindle has high requirements on the cleanliness of the gas introduced, and the introduction of gas in a grinding environment is likely to cause further contamination of the clean room.

[0005] Therefore, how to prevent the problem of increased pollution caused by ventilation gas while avoiding the reduction of accuracy due to wear is a technical problem that technicians in this field currently need to solve. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a semiconductor grinding spindle to prevent the problem of increased contamination caused by ventilation gas while avoiding the reduction of precision due to wear;

[0007] Another object of the present invention is to provide a semiconductor polishing device having the above-mentioned semiconductor polishing spindle.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A semiconductor grinding spindle, comprising:

[0010] Support base;

[0011] The main shaft body is supported on the supporting base through a magnetic levitation device, one end of the main shaft body is used to set the grinding disk, and the magnetic levitation device at least includes an axial magnetic levitation component and a radial magnetic levitation component. The axial magnetic levitation component is used to provide axial support force for the main shaft body, and the radial magnetic levitation component is used to provide radial support force for the main shaft body.

[0012] Optionally, in the above-mentioned semiconductor grinding spindle, the axial magnetic levitation assembly includes:

[0013] An axial permanent magnet is arranged on the main shaft body;

[0014] A first axial electromagnetic device is disposed on the support base and is located on a first side of the axial permanent magnet along the axial direction of the main shaft body, and generates a repulsive force with the axial permanent magnet;

[0015] The second axial electromagnetic device is arranged on the supporting base and is located at a second side of the axial permanent magnet along the axial direction of the main shaft body, and generates a repulsive force with the axial permanent magnet.

[0016] Optionally, in the above-mentioned semiconductor grinding spindle, the first axial electromagnetic device is located on a side of the axial permanent magnet away from the grinding disk, and the second axial electromagnetic device is located on a side of the axial permanent magnet close to the grinding disk;

[0017] The first axial electromagnetic device includes a plurality of groups of axial electromagnetic coils, and each group of the axial electromagnetic coils can be controlled separately.

[0018] Optionally, in the above-mentioned semiconductor grinding spindle, an axial position detection system is further included, and the axial position detection system is used to detect the distance between the first axial electromagnetic device and the axial permanent magnet;

[0019] The number of starting groups of the axial electromagnetic coils of the first axial electromagnetic device is inversely proportional to the distance between the first axial electromagnetic device and the axial permanent magnet.

[0020] Optionally, in the above semiconductor grinding spindle, an axial position detection system is also included, and the axial position detection system includes:

[0021] A first induction member is disposed on one of the support base and the spindle body;

[0022] The second induction member is arranged on the other of the support base and the spindle body. There are multiple second induction members, and the second induction members are arranged at intervals along the direction from close to the grinding disk to far away from the grinding disk. The farther the second induction member is from the grinding disk, the more groups of axial electromagnetic coils it corresponds to. When the first induction member senses the second induction member, the corresponding groups of axial electromagnetic coils corresponding to the second induction member are started.

[0023] Optionally, in the semiconductor grinding spindle, the number of the second sensing members is four, and along the direction from close to the grinding disk to away from the grinding disk, they are respectively a first position sensing member, a second position sensing member, a third position sensing member and a fourth position sensing member;

[0024] The first axial electromagnetic device includes four groups of axial electromagnetic coils;

[0025] When the first sensing element senses the first position sensing element, the first axial electromagnetic device activates a group of the axial electromagnetic coils;

[0026] When the first sensing element senses the second position sensing element, the first axial electromagnetic device activates the two groups of axial electromagnetic coils;

[0027] When the first sensing element senses the third position sensing element, the first axial electromagnetic device activates the three groups of axial electromagnetic coils;

[0028] When the first sensing element senses the fourth position sensing element, the first axial electromagnetic device activates the four groups of axial electromagnetic coils.

[0029] Optionally, in the above-mentioned semiconductor grinding spindle, each group of the axial electromagnetic coils of the first axial electromagnetic device consists of four coils evenly arranged along the circumferential direction.

[0030] Optionally, in the above-mentioned semiconductor grinding spindle, the axial position detection system further comprises a safety limit sensing member, the safety limit sensing member and the second sensing member are arranged on the same component and arranged on a side of the second sensing member away from the grinding disc;

[0031] When the first sensing element senses the safety limit sensing element, the spindle body is controlled to stop the thinning operation.

[0032] Optionally, in the above-mentioned semiconductor grinding spindle, an intelligent recognition system and a control system are also included, and the intelligent recognition system includes a recognition camera;

[0033] The recognition camera is used to detect whether there are foreign objects attached to the surface of the wafer before grinding, and to detect whether there are cracks on the wafer after each grinding of a preset thickness;

[0034] The control system is used to control the spindle body to stop the thinning operation when foreign matter is attached to the surface of the wafer and / or cracks exist on the wafer.

[0035] Optionally, in the above-mentioned semiconductor grinding spindle, the intelligent identification system further comprises a wafer thickness measuring device, and the wafer thickness measuring device is used to detect the thickness value of the wafer after each grinding of a preset thickness;

[0036] The control system is used to increase the current value of the axial electromagnetic coil corresponding to the area with larger thickness value of the wafer or reduce the current value of the axial electromagnetic coil corresponding to the area with smaller thickness value of the wafer when the difference between the maximum and minimum thickness values ​​of each area of ​​the wafer exceeds a preset thickness value.

[0037] Optionally, in the above semiconductor grinding spindle, the radial magnetic levitation component includes a first radial magnetic levitation component and a second radial magnetic levitation component, and the first radial magnetic levitation component and the second radial magnetic levitation component are respectively located on both sides of the axial magnetic levitation component;

[0038] The first radial magnetic levitation assembly includes a first radial permanent magnet and a first radial electromagnetic device, wherein the first radial permanent magnet is disposed on the main shaft body, and the first radial electromagnetic device is disposed on the support base and is located radially outside the first radial permanent magnet and generates a repulsive force with the first radial permanent magnet;

[0039] The second radial magnetic levitation assembly includes a second radial permanent magnet and a second radial electromagnetic device. The second radial permanent magnet is arranged on the main shaft body. The second radial electromagnetic device is arranged on the support base and is located radially outside the second radial permanent magnet and generates a repulsive force with the second radial permanent magnet.

[0040] Optionally, in the above-mentioned semiconductor grinding spindle, an automatic balancing system is further included, the automatic balancing system includes a distance measuring sensor arranged on the support base, the distance measuring sensors are multiple and symmetrically arranged along the center of the spindle body, and the distance measuring sensors are used to detect the distance to the target position along the axial direction parallel to the spindle body;

[0041] When the distance measured by at least one of the distance measuring sensors is less than a preset distance value, the currents of the first radial electromagnetic device and the second radial electromagnetic device are adjusted until the distances measured by each of the distance measuring sensors are not less than the preset distance value.

[0042] Optionally, in the above-mentioned semiconductor grinding spindle, before the thinning work, the distance value measured by the distance measuring sensor is the initial distance value, and after the thinning work, the distance value measured by the distance measuring sensor is the working distance value, and when the difference between the working distance value and the initial distance value is equal to the thinning target value, the spindle body stops the thinning work.

[0043] Optionally, in the above-mentioned semiconductor grinding spindle, the support base includes a first support, a second support, a third support and a fourth support which are detachably connected in sequence along a direction away from the grinding disk to close to the grinding disk;

[0044] The first support is provided with a stator corresponding to the rotor on the main shaft body;

[0045] The second support comprises a first mounting portion and a second mounting portion which are coaxially arranged, and a supporting disk portion connecting the first mounting portion and the second mounting portion, the second radial electromagnetic device is arranged on the first mounting portion, the first axial electromagnetic device is arranged on the supporting disk portion, and the radial magnetic levitation assembly is arranged on a side of the second mounting portion facing the main shaft body;

[0046] The second axial electromagnetic device is disposed on the third support, and the first radial electromagnetic device is disposed on the fourth support.

[0047] The semiconductor grinding spindle provided by the present invention supports the spindle body on the support base through a magnetic levitation device, and the magnetic levitation device at least includes an axial magnetic levitation component and a radial magnetic levitation component. The axial magnetic levitation component is used to make the spindle body suspended in the axial direction, and the radial magnetic levitation component is used to make the spindle body suspended in the radial direction. The present invention constructs a magnetic field between the spindle body and the support base to generate an interaction force, so that the spindle body is in a suspended state, forming a rotating support without mechanical contact, so that the friction loss is small, and because there is no friction, the problem of reduced precision due to wear is avoided, and gas is not required as a lubricant, so the pollution problem caused by the introduction of gas can be avoided.

[0048] A semiconductor grinding device comprises a semiconductor grinding spindle as described in any one of the above items.

[0049] The semiconductor grinding equipment provided by the present invention has the above-mentioned semiconductor grinding spindle, and therefore has all the technical effects of the above-mentioned semiconductor grinding spindle, which will not be described in detail herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A cross-sectional view of a semiconductor grinding spindle disclosed in an embodiment of the present invention along an axial direction;

[0052] Figure 2 for Figure 1 Section view along line AA;

[0053] Figure 3 for Figure 1 Sectional view along line CC;

[0054] Figure 4 for Figure 1 Sectional view along line BB;

[0055] Figure 5 It is a partial enlarged view of the position of the axial position detection system and the automatic balancing system disclosed in the embodiment of the present invention;

[0056] Figure 6 The figure is a schematic diagram of the structure of the intelligent recognition system disclosed in the embodiment of the present invention.

[0057] The meanings of the reference numerals in the figures are as follows:

[0058] 100-spindle body;

[0059] 210 - a first radial electromagnetic device; 220 - a first radial permanent magnet;

[0060] 310-first axial electromagnetic device; 311-first group of axial coils; 312-second group of axial coils; 313-third group of axial coils; 314-fourth group of axial coils; 320-axial permanent magnet; 330-second axial electromagnetic device;

[0061] 410 - a second radial electromagnetic device; 420 - a second radial permanent magnet;

[0062] 510-first support; 520-second support; 530-third support; 540-fourth support;

[0063] 610-stator; 620-rotor;

[0064] 710-first sensing element; 720-second sensing element; 721-first position sensing element; 722-second position sensing element; 723-third position sensing element; 724-fourth position sensing element; 730-safety limit sensing element; 740-distance measuring sensor;

[0065] 800-grinding table;

[0066] 900-intelligent recognition system; 910-recognition camera; 920-wafer thickness measurement device. DETAILED DESCRIPTION

[0067] The core of the present invention is to provide a semiconductor grinding spindle to prevent the problem of increased pollution caused by ventilation gas while avoiding the reduction of precision due to wear;

[0068] Another core of the present invention is to provide a semiconductor polishing device having the above-mentioned semiconductor polishing spindle.

[0069] 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.

[0070] like Figure 1 As shown, an embodiment of the present invention discloses a semiconductor grinding spindle, which is used for grinding and thinning the raw material of semiconductor chips - wafers. The semiconductor chips can be chips used in new energy vehicles or chips used in electronic devices. This embodiment does not limit the application field of semiconductor chips. The semiconductor grinding spindle includes a support base and a spindle body 100. Among them, the spindle body 100 is supported on the support base by a magnetic levitation device, and one end of the spindle body 100 is used to set a grinding disc, and the wafer 1000 fixed on the carrier 800 is ground by the grinding disc.

[0071] The magnetic levitation device at least includes an axial magnetic levitation component and a radial magnetic levitation component. The axial magnetic levitation component is used to provide axial support for the main shaft body 100, so that the main shaft body 100 can be suspended in the axial direction under the action of magnetic force. The radial magnetic levitation component is used to provide radial support for the main shaft body 100, so that the main shaft body 100 can be suspended in the radial direction under the action of magnetic force.

[0072] The present invention constructs a magnetic field between the spindle body 100 and the support base to generate an interaction force, so that the spindle body 100 is in a suspended state, forming a rotating support without mechanical contact, so the friction loss is small, and because there is no friction, the problem of reduced accuracy due to wear is avoided, and gas is not required as a lubricant, so the pollution problem caused by the introduction of gas can be avoided.

[0073] Furthermore, the axial magnetic levitation assembly includes an axial permanent magnet 320, a first axial electromagnetic device 310 and a second axial electromagnetic device 330. The axial permanent magnet 320 may be an annular structure and fixed to the main shaft body 100, so that when the axial permanent magnet 320 rotates with the main shaft body 100, the axial permanent magnet 320 may always interact with the first axial electromagnetic device 310 and the second axial electromagnetic device 330 because of the annular structure, and the force will not change with the rotation.

[0074] Since the first axial electromagnetic device 310 needs to be powered, in order to facilitate the layout of the circuit, the first axial electromagnetic device 310 is set on a fixed support base, which can facilitate the layout of the circuit. The first axial electromagnetic device 310 is located on the first side of the axial permanent magnet 320 along the axial direction of the main shaft body 100, and generates a repulsive force with the axial permanent magnet 320, that is, after the first axial electromagnetic device 310 is powered, an electromagnetic force is generated, and the electromagnetic force repels the magnetic force of the axial permanent magnet 320, pushing the axial permanent magnet 320 to move in a direction away from the first axial electromagnetic device 310.

[0075] For the same reason as above, the second axial electromagnetic device 330 is disposed on a fixed support base and is located on the second side of the axial permanent magnet 320 along the axial direction of the main shaft body 100, and generates a repulsive force with the axial permanent magnet 320. That is, the second axial electromagnetic device 330 and the first axial electromagnetic device 310 are respectively located on both sides of the axial permanent magnet 320. After the second axial electromagnetic device 330 is energized, an electromagnetic force is generated, and the electromagnetic force repels the magnetic force of the axial permanent magnet 320, pushing the axial permanent magnet 320 to move in a direction away from the second axial electromagnetic device 330.

[0076] In this embodiment, a second axial electromagnetic device 330 and a first axial electromagnetic device 310 are respectively arranged on both sides of the axial permanent magnet 320, and the second axial electromagnetic device 330 and the first axial electromagnetic device 310 generate forces in opposite directions on the axial permanent magnet 320. In an ideal state, the axial permanent magnet 320 can be kept in the middle position between the second axial electromagnetic device 330 and the first axial electromagnetic device 310, so that the main shaft body 100 is suspended in the axial direction and does not contact the second axial electromagnetic device 330 and the first axial electromagnetic device 310. When the main shaft body 100 rotates, it only needs to overcome the air resistance, and does not need to overcome the contact friction between the axial magnetic suspension components.

[0077] In order to facilitate understanding of the scheme disclosed in the embodiment of the present invention, the axial positions of the first axial electromagnetic device 310 and the second axial electromagnetic device 330 are defined. For example, the first axial electromagnetic device 310 is defined to be located on the side of the axial permanent magnet 320 away from the grinding disk, and the second axial electromagnetic device 330 is defined to be located on the side of the axial permanent magnet 320 close to the grinding disk.

[0078] During the grinding process, the spindle body 100 is subjected to an axial thrust in the direction away from the grinding disc. This axial thrust will drive the axial permanent magnet 320 to move in the direction of the first axial electromagnetic device 310, so that the distance between the two is reduced, and in extreme cases, the two may come into contact. In order to avoid this phenomenon, in this embodiment, the first axial electromagnetic device 310 is configured to include multiple groups of axial electromagnetic coils, and each group of axial electromagnetic coils can be controlled separately. This allows the number of groups of energized axial electromagnetic coils to be selected according to the magnitude of the axial thrust. For example, when the axial thrust is small, only one group of axial electromagnetic coils can be started, and when the axial thrust is large, multiple groups of axial electromagnetic coils can be started to generate a larger electromagnetic repulsion force to overcome the axial displacement of the spindle body 100 caused by the large axial thrust.

[0079] In order to automatically adjust the number of axial electromagnetic coil groups to be started according to the axial thrust, in this embodiment, an axial position detection system may also be included, and the axial position detection system is used to detect the distance between the first axial electromagnetic device 310 and the axial permanent magnet 320. The distance between the first axial electromagnetic device 310 and the axial permanent magnet 320 is relatively close, indicating that the axial thrust generated during the grinding process is relatively large, causing the spindle body 100 to be displaced.

[0080] The number of starting groups of the axial electromagnetic coils of the first axial electromagnetic device 310 is inversely proportional to the distance between the second axial electromagnetic device 330 and the axial permanent magnet 320. That is, the smaller the distance between the second axial electromagnetic device 330 and the axial permanent magnet 320, the more the number of starting groups of the axial electromagnetic coils of the first axial electromagnetic device 310; conversely, the larger the distance between the second axial electromagnetic device 330 and the axial permanent magnet 320, the fewer the number of starting groups of the axial electromagnetic coils of the first axial electromagnetic device 310, so as to keep the axial permanent magnet 320 in the central position as much as possible.

[0081] like Figure 5As shown, in another embodiment of the present invention, an axial position detection system may also be included, and the axial position detection system includes a first sensing member 710 and a second sensing member 720. The first sensing member 710 and the second sensing member 720 form a position sensor, that is, when the first sensing member 710 and the second sensing member 720 correspond to each other, they are triggered to detect the axial position of the spindle body 100. The position sensor needs to select a non-contact sensor, that is, a proximity position sensor, such as a common electromagnetic position sensor, a photoelectric position sensor, a differential transformer position sensor, an ultrasonic position sensor, etc.

[0082] The first induction member 710 is disposed on one of the support base and the spindle body 100, and the second induction member 720 is disposed on the other of the support base and the spindle body 100. In this embodiment, the first induction member 710 is disposed on the spindle body 100, and the second induction member 720 is disposed on the support base.

[0083] There are multiple second sensing members 720, and the second sensing members 720 are arranged at intervals along the direction from close to the grinding disk to far away from the grinding disk. The second sensing members 720 that are farther away from the grinding disk have more groups of axial electromagnetic coils corresponding to them. When the first sensing member 710 senses the second sensing member 720, the corresponding groups of axial electromagnetic coils corresponding to the second sensing member 720 are started.

[0084] Figure 5 In the illustrated solution, there are four second sensing members 720, and along the direction from close to the grinding disc to far from the grinding disc, they are respectively the first position sensing member 721, the second position sensing member 722, the third position sensing member 723 and the fourth position sensing member 724. When the first sensing member 710 corresponds to the first position sensing member 721, the distance between the first axial electromagnetic device 310 and the axial permanent magnet 320 is large; when the first sensing member 710 moves with the spindle body 100 to correspond to the second position sensing member 722, the distance between the first axial electromagnetic device 310 and the axial permanent magnet 320 becomes smaller, and the distance reduced from the previous distance is the distance between the first position sensing member 721 and the second position sensing member 722; if the spindle body 100 moves a large amount, such as when the first sensing member 710 corresponds to the fourth position sensing member 724, the distance between the first axial electromagnetic device 310 and the axial permanent magnet 320 is the smallest. The first position sensing element 721 , the second position sensing element 722 , the third position sensing element 723 and the fourth position sensing element 724 may be arranged in sequence at equal intervals.

[0085] The first axial electromagnetic device 310 includes four groups of axial electromagnetic coils. When the first sensing member 710 senses the first position sensing member 721, the first axial electromagnetic device 310 starts a group of axial electromagnetic coils. That is, when the first sensing member 710 moves away from the grinding disc to the first position sensing member 721, or exceeds the first position sensing member 721 but does not exceed the second position sensing member 722, it means that the first sensing member 710 senses the first position sensing member 721 but does not sense the second position sensing member 722, then the first axial electromagnetic device 310 starts a group of axial electromagnetic coils to generate one unit of electromagnetic force. It should be noted that one unit of electromagnetic force is the electromagnetic force generated by a group of axial electromagnetic coils.

[0086] When the first sensing element 710 senses the second position sensing element 722, the first axial electromagnetic device 310 activates two sets of axial electromagnetic coils. That is, when the first sensing element 710 moves away from the grinding disc to the second position sensing element 722, or exceeds the second position sensing element 722 but does not exceed the third position sensing element 723, it means that the first sensing element 710 senses the second position sensing element 722 but does not sense the third position sensing element 723, then the first axial electromagnetic device 310 activates two sets of axial electromagnetic coils to generate two units of electromagnetic force, that is, the electromagnetic force generated by the two sets of axial electromagnetic coils.

[0087] When the first sensing element 710 senses the third position sensing element 723, the first axial electromagnetic device 310 activates the three sets of axial electromagnetic coils. That is, when the first sensing element 710 moves away from the grinding disc to the third position sensing element 723, or exceeds the third position sensing element 723 but does not exceed the fourth position sensing element 724, it means that the first sensing element 710 senses the third position sensing element 723 but does not sense the fourth position sensing element 724, then the first axial electromagnetic device 310 activates the three sets of axial electromagnetic coils to generate three units of electromagnetic force, that is, the electromagnetic force generated by the three sets of axial electromagnetic coils.

[0088] When the first sensing element 710 senses the fourth position sensing element 724, the first axial electromagnetic device 310 activates four sets of axial electromagnetic coils. That is, the first sensing element 710 moves away from the grinding disc to the fourth position sensing element 724, or exceeds the fourth position sensing element 724, indicating that the first sensing element 710 senses the fourth position sensing element 724, and the first axial electromagnetic device 310 activates four sets of axial electromagnetic coils to generate four units of electromagnetic force, that is, the electromagnetic force generated by the four sets of axial electromagnetic coils.

[0089] like Figure 2 As shown, the four groups of axial electromagnetic coils may be respectively a first group of axial coils 311, a second group of axial coils 312, a third group of axial coils 313, and a fourth group of axial coils 314. Each group of axial electromagnetic coils should include a plurality of electromagnetic coils. Figure 2 In the illustrated scheme, each group of axial electromagnetic coils of the first axial electromagnetic device 310 is four evenly arranged in the circumferential direction. Taking the first group of axial coils 311 as an example, the four first groups of axial coils 311 are respectively at the 0 o'clock direction, the 3 o'clock direction, the 6 o'clock direction and the 9 o'clock direction (the specific positions are examples and should not limit the present scheme). The second groups of axial coils 312 are respectively spaced 22.5° clockwise along the first group of axial coils 311, the third groups of axial coils 313 are respectively spaced 22.5° clockwise along the second group of axial coils 312, and the fourth groups of axial coils 314 are respectively spaced 22.5° clockwise along the third group of axial coils 313.

[0090] Furthermore, the axial position detection system further includes a safety limit sensing member 730, which is disposed on the same component as the second sensing member 720. In this embodiment, the safety limit sensing member 730 and the second sensing member 720 can both be disposed on the support base. The safety limit sensing member 730 is disposed on a side of the second sensing member 720 away from the grinding disc.

[0091] When the first sensing element 710 senses the safety limit sensing element 730 , it indicates that the grinding load has been exceeded. To ensure safety, the spindle body 100 is controlled to stop the thinning operation.

[0092] It should be noted that an initial position sensing member may also be provided on the side of the second sensing member 720 close to the grinding disc. Before performing the grinding work, it is first necessary to start the second axial electromagnetic device 330 so that the spindle body 100 is suspended in the vertical direction (i.e., the axial direction of the spindle body 100), and the axial permanent magnet 320 is pushed to move away from the second axial electromagnetic device 330. The first sensing member 710 moves with the spindle body 100 in the direction away from the grinding disc to the initial position sensing member, or exceeds the initial position sensing member, indicating that the first sensing member 710 should be able to generate induction with the initial position sensing member. If induction can be generated, it means that the axial position detection system can work normally, and subsequent grinding work can be performed.

[0093] Furthermore, the embodiment of the present invention may also include an alarm device. After the second axial electromagnetic device 330 is started, and the first sensing element 710 and the initial position sensing element cannot effectively sense, the alarm device sends an alarm message. That is, when the first sensing element 710 cannot sense the initial position sensing element, or the initial position sensing element cannot sense the first sensing element 710, it indicates that there is a fault in the axial position detection system or the second axial electromagnetic device 330, and the alarm device sends an alarm message to remind the operator to repair it in time. The present invention does not limit the alarm form of the alarm device, which can be one or a combination of sound and light alarms.

[0094] like Figure 3As shown, since the function of the second axial electromagnetic device 330 is to keep the spindle body 100 suspended in the vertical direction, the required bearing capacity is small and consistent with the direction of the axial thrust during the grinding process, so there is no need to increase the electromagnetic force due to the generation of the axial thrust. Based on this, only four second axial electromagnetic devices 330 can be set, evenly distributed along the circumferential direction, so that they are arranged symmetrically along the axis center of the spindle body 100, ensuring that the thrust applied to the spindle body 100 is relatively uniform.

[0095] like Figure 1 and Figure 6 As shown, in a specific embodiment of the present invention, the present invention may further include an intelligent recognition system 900 and a control system, and the intelligent recognition system 900 includes a recognition camera 910 .

[0096] The recognition camera 910 is used to detect whether there are foreign objects attached to the surface of the wafer 1000 before grinding, and to detect whether there are cracks on the wafer 1000 after each grinding to a preset thickness. It should be noted that the wafer is ground multiple times in stages and gradually ground to the target thickness. Each time, only the preset thickness is ground, and after each grinding, the recognition camera 910 needs to be used to detect whether there are cracks on the wafer 1000.

[0097] The control system is used to control the spindle body 100 to stop the thinning operation when foreign matter is attached to the surface of the wafer 1000 and / or cracks exist in the wafer 1000 .

[0098] Before grinding the wafer 1000, the recognition camera 910 first detects whether there are foreign objects on its surface. If the wafer 1000 is ground under the premise of foreign objects, it will affect the quality of the wafer 1000. At this time, it is necessary to control the spindle body 100 to stop the thinning work and continue grinding after cleaning the foreign objects.

[0099] During the grinding process, the wafer 1000 may break due to unstable grinding force. The recognition camera 910 detects whether there are cracks on the wafer 1000 after each stage of grinding. Once cracks appear, the spindle body 100 is controlled to stop the thinning operation.

[0100] Furthermore, the intelligent identification system 900 further includes a wafer thickness measuring device 920, which is used to detect the thickness value of the wafer 1000 after each grinding to a preset thickness. The wafer thickness measuring device 920 can be a contact thickness measuring device or a non-contact thickness measuring device.

[0101] The wafer usually needs to be ground multiple times to reach the target thickness. When a grinding is completed, the wafer thickness measuring device 920 detects the thickness value of each area of ​​the wafer 1000. If the difference between the maximum and minimum thickness values ​​of each area exceeds the preset thickness value, it means that the grinding disc is tilted, resulting in eccentric wear of the wafer 1000, causing some locations to be thicker and some locations to be thinner. During the grinding process, the wafer 1000 is also rotated by the carrier. If the grinding disc and the carrier are not parallel and there is a small angle, eccentric wear will occur.

[0102] When the difference between the maximum and minimum thickness values ​​of each area of ​​wafer 1000 exceeds a preset thickness value, the control system increases the current value of the axial electromagnetic coil corresponding to the area with a larger thickness value of wafer 1000 or decreases the current value of the axial electromagnetic coil corresponding to the area with a smaller thickness value of wafer 1000.

[0103] The eccentric wear phenomenon is caused by the tilt of the grinding disc. The fundamental reason is the imbalance of the electromagnetic force of the axial electromagnetic coil along the circumferential direction. The position with a larger thickness value of wafer 1000 indicates that the part of the grinding disc grinding this area is farther away from the carrier; on the contrary, the position with a smaller thickness value of wafer 1000 indicates that the part of the grinding disc grinding this area is closer to the carrier. The electromagnetic force generated by the axial electromagnetic coil can be adjusted by adjusting the current of the axial electromagnetic coil at the corresponding position, thereby changing the distance between the corresponding area of ​​the grinding disc and the carrier to avoid eccentric wear during the next grinding.

[0104] like Figure 1 As shown, the radial magnetic levitation assembly includes a first radial magnetic levitation assembly and a second radial magnetic levitation assembly, and the first radial magnetic levitation assembly and the second radial magnetic levitation assembly are respectively located on both sides of the axial magnetic levitation assembly to ensure that uniform support force is provided for the main shaft body 100 in the radial direction.

[0105] The first radial magnetic levitation assembly includes a first radial permanent magnet 220 and a first radial electromagnetic device 210, wherein the first radial permanent magnet 220 can be an annular structure and is arranged on the main shaft body 100, so that when the first radial permanent magnet 220 rotates with the main shaft body 100, since the first radial permanent magnet 220 is an annular structure, it can always interact with the first radial electromagnetic device 210, and the force will not change with the rotation.

[0106] Since the first radial electromagnetic device 210 needs to be powered on, in order to facilitate the layout of the circuit, the first radial electromagnetic device 210 is set on a fixed support base, which can facilitate the layout of the circuit. The first radial electromagnetic device 210 is located radially outside the first radial permanent magnet 220 and generates a repulsive force with the first radial permanent magnet 220. That is, after the first radial electromagnetic device 210 is powered on, an electromagnetic force is generated, and the electromagnetic force repels the magnetic force of the first radial permanent magnet 220, generating an electromagnetic force that pushes the first radial permanent magnet 220 to move toward the center direction, so that the axis of the main shaft body 100 remains at the position of the rotation center of the first radial electromagnetic device 210.

[0107] The second radial magnetic levitation assembly includes a second radial permanent magnet 420 and a second radial electromagnetic device 410, wherein the second radial permanent magnet 420 can be an annular structure and is arranged on the main shaft body 100, so that when the second radial permanent magnet 420 rotates with the main shaft body 100, since the second radial permanent magnet 420 is an annular structure, it can always interact with the second radial electromagnetic device 410, and the force will not change with the rotation.

[0108] Since the second radial electromagnetic device 410 needs to be powered on, in order to facilitate the layout of the circuit, the second radial electromagnetic device 410 is arranged on a fixed support base, which can facilitate the layout of the circuit. The second radial electromagnetic device 410 is arranged on the support base, and is located radially outside the second radial permanent magnet 420, and generates a repulsive force with the second radial permanent magnet 420. That is, after the second radial electromagnetic device 410 is powered on, an electromagnetic force is generated, and the electromagnetic force repels the magnetic force of the second radial permanent magnet 420, generating an electromagnetic force that pushes the second radial permanent magnet 420 to move toward the center direction, so that the axis of the spindle body 100 remains at the position of the rotation center of the second radial electromagnetic device 410.

[0109] like Figure 4 As shown, since the structures of the first radial electromagnetic device 210 and the second radial electromagnetic device 410 are the same, Figure 1 The cross-sectional view of the second radial electromagnetic device 410 along the BB line has the same structure as the cross-sectional view of the first radial electromagnetic device 210 along the BB line. Figure 4 The structure shown is therefore only one figure.

[0110] In this embodiment, the second radial electromagnetic device 410 and the first radial electromagnetic device 210 may each include four electromagnetic coils, which are evenly positioned in the circumferential direction around the main shaft body 100 .

[0111] like Figure 5As shown, an embodiment of the present invention may also include an automatic balancing system, which includes a distance sensor 740 disposed on a support base, wherein there are multiple distance sensors 740, which are symmetrically arranged along the center of the spindle body 100, and the distance sensor 740 is used to detect the distance to the target position along the axial direction parallel to the spindle body 100. It should be noted that the target position can be the position of a certain shoulder on the spindle body 100, or the position of a certain permanent magnet, as long as the signal of the distance sensor 740 can be blocked so that the distance sensor 740 can detect the distance to the position of the blocked signal. In addition, it can be understood by those skilled in the art that when the axial direction of the spindle body 100 is in a balanced state, the distances detected by each distance sensor 740 should be the same.

[0112] The axial balance of the main shaft body 100 means that the axis of the main shaft body 100 is collinear with the axis of the cylinder formed by each second radial electromagnetic device 410 , and is also collinear with the axis of the cylinder formed by each first radial electromagnetic device 210 .

[0113] When the distance measured by at least one of the distance measuring sensors 740 is less than the preset distance value, the current of the first radial electromagnetic device 210 and the second radial electromagnetic device 410 is adjusted until the distance measured by each distance measuring sensor 740 is not less than the preset distance value. The preset distance value can be set according to demand. For example, the preset distance value can be set according to the target distance value (referring to the distance value when the spindle body 100 is in a balanced state). For example, the preset distance value is designed to be equal to the target distance value, or it can be designed to be slightly smaller than the target distance value, so as to avoid repeatedly adjusting the current of the first radial electromagnetic device 210 and the second radial electromagnetic device 410.

[0114] Taking four ranging sensors 740 as an example, the corresponding first radial electromagnetic device 210 and the second radial electromagnetic device 410 may also each include four radial electromagnetic coils. The four radial electromagnetic coils of the first radial electromagnetic device 210 and the second radial electromagnetic device 410 and the four ranging sensors 740 are respectively located on the same straight line parallel to the axial direction of the main shaft body 100.

[0115] For example, a radial electromagnetic coil of the first radial electromagnetic device 210, a radial electromagnetic coil of the second radial electromagnetic device 410, and one of the distance measuring sensors 740 are located on the same straight line, so that four straight lines are arranged, and each straight line is arranged with a radial electromagnetic coil of the first radial electromagnetic device 210, a radial electromagnetic coil of the second radial electromagnetic device 410, and a distance measuring sensor 740.

[0116] If the distance value detected by one of the distance measuring sensors 740 is less than the preset distance value, it means that the radial electromagnetic coil of the first radial electromagnetic device 210 and the radial electromagnetic coil of the second radial electromagnetic device 410 located on the same straight line as the distance measuring sensor 740 need to be adjusted. Specifically, the current of the electromagnetic coil in front of the distance measuring sensor 740 (i.e., facing the direction in which the distance measuring sensor 740 sends a signal) can be increased, and the current of the electromagnetic coil behind the distance measuring sensor 740 (i.e., facing away from the direction in which the distance measuring sensor 740 sends a signal) can be decreased.

[0117] In this embodiment, before the thinning work (i.e., grinding work), the distance value measured by the distance sensor 740 is the initial distance value, and after the thinning work, the distance value measured by the distance sensor 740 is the working distance value. When the difference between the working distance value and the initial distance value is equal to the thinning target value, the spindle body 100 stops the thinning work. That is, in this embodiment, the distance sensor 740 can be used to detect the thickness of the thinning work, so that when the target thinning amount is reached, the spindle body 100 is controlled to stop the thinning work.

[0118] like Figure 1 As shown, the support base includes a first support 510, a second support 520, a third support 530 and a fourth support 540 which are detachably connected in sequence along the direction away from the grinding disc to the direction close to the grinding disc. In this embodiment, the support base is designed as four detachably connected parts, which can facilitate the installation and maintenance of the components thereon.

[0119] The first support 510 is provided with a stator 610 corresponding to the rotor 620 on the main shaft body 100, and the cooperation between the rotor 620 and the stator 610 provides the main shaft body 100 with rotational power. The second support 520 has a first mounting portion and a second mounting portion arranged coaxially and a support disk portion connecting the first mounting portion and the second mounting portion, the second radial electromagnetic device 410 is provided on the first mounting portion, the first axial electromagnetic device 310 is provided on the support disk portion, and the radial magnetic levitation assembly is provided on the side of the second mounting portion facing the main shaft body 100. The second axial electromagnetic device 330 is provided on the third support 530, and the first radial electromagnetic device 210 is provided on the fourth support 540.

[0120] Since the first support 510 and the fourth support 540 are arranged at the two ends of the main shaft body 100, the first support 510 and the fourth support 540 can be an integrated structure and installed by the ends of the main shaft body 100; the second support 520 and the third support 530 are located in the middle position. In order to facilitate separate disassembly and assembly, the second support 520 and the third support 530 can be composed of two parts, and after being buckled, they are assembled into a whole by fasteners, so that the second support 520 and the third support 530 can be disassembled and assembled along the radial direction of the main shaft body 100. The present invention divides the support base into the first support 510, the second support 520, the third support 530 and the fourth support 540 that are detachably connected, which can be easily disassembled for maintenance.

[0121] The embodiment of the present invention further discloses a semiconductor grinding device, which includes the semiconductor grinding spindle disclosed in the above embodiment. Since it has the above semiconductor grinding spindle, it has all the technical effects of the above semiconductor grinding spindle, which will not be described in detail herein.

[0122] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0123] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0124] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0125] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A semiconductor grinding spindle, characterized in that: include: Support base; The spindle body is supported on the support base by a magnetic levitation device, one end of the spindle body is used to set a grinding disc, and the magnetic levitation device at least includes an axial magnetic levitation component and a radial magnetic levitation component, the axial magnetic levitation component is used to provide axial support force for the spindle body, and the radial magnetic levitation component is used to provide radial support force for the spindle body; The axial magnetic levitation assembly comprises: An axial permanent magnet is arranged on the main shaft body; A first axial electromagnetic device is disposed on the support base and is located on a side of the axial permanent magnet away from the grinding disc, and generates a repulsive force with the axial permanent magnet; A second axial electromagnetic device is disposed on the support base and is located on a side of the axial permanent magnet close to the grinding disc, and generates a repulsive force with the axial permanent magnet, wherein the first axial electromagnetic device includes a plurality of groups of axial electromagnetic coils, and each group of the axial electromagnetic coils can be controlled separately; Also included is an axial position detection system, the axial position detection system comprising: A first induction member is disposed on one of the support base and the spindle body; A second induction member is disposed on the other of the support base and the spindle body, the second induction members are multiple, and the second induction members are arranged at intervals in a direction from close to the grinding disc to far away from the grinding disc, and the second induction members farther from the grinding disc correspond to more groups of axial electromagnetic coils, and when the first induction member senses the second induction member, the corresponding groups of axial electromagnetic coils corresponding to the second induction member are activated; The axial position detection system further comprises a safety limit sensing element, wherein the safety limit sensing element and the second sensing element are arranged on the same component and arranged on a side of the second sensing element away from the grinding disc; When the first sensing element senses the safety limit sensing element, the spindle body is controlled to stop the thinning operation; It also includes an initial position sensing member, which is located on one side of the second sensing member close to the grinding disc; before grinding, the second axial electromagnetic device is started, so that the spindle body is suspended in the vertical direction, pushing the axial permanent magnet to move in a direction away from the second axial electromagnetic device; the first sensing member moves with the spindle body in a direction away from the grinding disc to the initial position sensing member, or exceeds the initial position sensing member, and if the first sensing member can generate induction with the initial position sensing member, the axial position detection system can work normally, and subsequent grinding can be carried out; It also includes an intelligent recognition system and a control system, wherein the intelligent recognition system includes a recognition camera; The recognition camera is used to detect whether there are foreign objects attached to the surface of the wafer before grinding; the wafer is ground multiple times in stages during the grinding process, and the recognition camera is used to detect whether there are cracks on the wafer after each grinding of a preset thickness; The control system is used to control the spindle body to stop the thinning operation when foreign matter is attached to the surface of the wafer and / or cracks exist on the wafer; The intelligent identification system also includes a wafer thickness measuring device, which is used to detect the thickness value of the wafer after grinding to a preset thickness each time; The control system is used to increase the current value of the axial electromagnetic coil corresponding to the area with larger thickness value of the wafer or reduce the current value of the axial electromagnetic coil corresponding to the area with smaller thickness value of the wafer when the difference between the maximum and minimum thickness values ​​of each area of ​​the wafer exceeds a preset thickness value.

2. The semiconductor grinding spindle according to claim 1, characterized in that: The axial position detection system is used to detect the distance between the first axial electromagnetic device and the axial permanent magnet; The number of starting groups of the axial electromagnetic coils of the first axial electromagnetic device is inversely proportional to the distance between the first axial electromagnetic device and the axial permanent magnet.

3. The semiconductor grinding spindle according to claim 1, characterized in that: There are four second sensing elements, and along the direction from close to the grinding disc to far away from the grinding disc, they are respectively a first position sensing element, a second position sensing element, a third position sensing element and a fourth position sensing element; The first axial electromagnetic device includes four groups of axial electromagnetic coils; When the first sensing element senses the first position sensing element, the first axial electromagnetic device activates a group of the axial electromagnetic coils; When the first sensing element senses the second position sensing element, the first axial electromagnetic device activates the two groups of axial electromagnetic coils; When the first sensing element senses the third position sensing element, the first axial electromagnetic device activates the three groups of axial electromagnetic coils; When the first sensing element senses the fourth position sensing element, the first axial electromagnetic device activates the four groups of axial electromagnetic coils.

4. The semiconductor grinding spindle according to any one of claims 1 to 3, characterized in that: The radial magnetic levitation assembly comprises a first radial magnetic levitation assembly and a second radial magnetic levitation assembly, wherein the first radial magnetic levitation assembly and the second radial magnetic levitation assembly are respectively located on two sides of the axial magnetic levitation assembly; The first radial magnetic levitation assembly includes a first radial permanent magnet and a first radial electromagnetic device, wherein the first radial permanent magnet is disposed on the main shaft body, and the first radial electromagnetic device is disposed on the support base and is located radially outside the first radial permanent magnet and generates a repulsive force with the first radial permanent magnet; The second radial magnetic levitation assembly includes a second radial permanent magnet and a second radial electromagnetic device. The second radial permanent magnet is arranged on the main shaft body. The second radial electromagnetic device is arranged on the support base and is located radially outside the second radial permanent magnet and generates a repulsive force with the second radial permanent magnet.

5. The semiconductor grinding spindle according to claim 4, characterized in that: It also includes an automatic balancing system, the automatic balancing system includes a distance measuring sensor disposed on the support base, the distance measuring sensors are multiple and symmetrically arranged along the center of the spindle body, and the distance measuring sensors are used to detect the distance to the target position along the axial direction parallel to the spindle body; When the distance measured by at least one of the distance measuring sensors is less than a preset distance value, the currents of the first radial electromagnetic device and the second radial electromagnetic device are adjusted until the distances measured by each of the distance measuring sensors are not less than the preset distance value.

6. The semiconductor grinding spindle according to claim 5, characterized in that: Before the thinning work, the distance value measured by the distance measuring sensor is the initial distance value. After the thinning work, the distance value measured by the distance measuring sensor is the working distance value. When the difference between the working distance value and the initial distance value is equal to the thinning target value, the spindle body stops the thinning work.

7. The semiconductor grinding spindle according to claim 4, characterized in that: The support base includes a first support, a second support, a third support and a fourth support which are detachably connected in sequence along a direction away from the grinding disc and close to the grinding disc; The first support is provided with a stator corresponding to the rotor on the main shaft body; The second support comprises a first mounting portion and a second mounting portion which are coaxially arranged, and a supporting disk portion connecting the first mounting portion and the second mounting portion, the second radial electromagnetic device is arranged on the first mounting portion, the first axial electromagnetic device is arranged on the supporting disk portion, and the radial magnetic levitation assembly is arranged on a side of the second mounting portion facing the main shaft body; The second axial electromagnetic device is disposed on the third support, and the first radial electromagnetic device is disposed on the fourth support.

8. A semiconductor polishing device, characterized in that: It comprises a semiconductor grinding spindle as described in any one of claims 1 to 7.

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