Air bearing

Abstract

The invention relates to the technical field of semiconductors, in particular to an air bearing which comprises a shell, an air floating cavity is arranged in the shell, the shell is provided with multiple layers of air supply channel groups communicated with one another, the multiple layers of air supply channel groups are distributed in the first direction, and each air supply channel group is provided with multiple output ends evenly surrounding the air floating cavity. The output end of the air supply channel group is communicated with the air floatation chamber; the main shaft is rotationally connected into the air floatation cavity, the main shaft is in clearance fit with the inner wall of the shell, the main shaft is provided with a first air gallery, and the shell is provided with a first negative pressure air duct; at least one end face, in the first direction, of the shell is provided with an opening, the first adsorption channel communicates with the gap, and compressed gas flows out of the opening in the end of the shell and / or the first negative-pressure air channel, the uniformity of gas distribution in the air floatation cavity is ensured, radial run-out of the main shaft in the rotating process can be reduced, the rotating stability is improved, and the service life of the main shaft is prolonged. The uniformity of the gap between the main shaft and the shell is ensured, and the rotating stability of the main shaft is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an air bearing. Background Art

[0002] In the semiconductor packaging process, the main function of the die bonder is to accurately transfer the chip from the wafer to the packaging substrate, thereby fixing and connecting the chip. One of the core components of the die bonder, the bond head, is responsible for picking up and placing the chip. The bond head uses a series of precise mechanical structures, including components such as linear bearings, to achieve precise rotation during the working process, thereby driving the rotation and positioning of the chip.

[0003] As an important supporting component for the rotation of the bonding head, the performance of the linear bearing directly affects the overall accuracy and stability of the die bonding machine. The radial runout accuracy of the linear bearing is one of the important indicators to measure its performance, which reflects the degree to which the bearing deviates from the ideal axis during rotation. When the radial runout accuracy of the linear bearing is low, it will cause the bonding head to shake during rotation, thus affecting the precise placement of the chip.

[0004] Specifically, when the radial runout accuracy of the linear bearing is insufficient, the bonding head will deviate during rotation, which will directly cause the chip to shift position during the pick-up and placement process. Position shift will not only reduce the chip's fixation effect, but also affect the quality and efficiency of subsequent wire bonding, thus adversely affecting the overall performance and reliability of semiconductor products.

[0005] In addition, the low radial runout accuracy of the linear bearing may also cause vibration and noise of the bonding head, which will not only reduce the working stability of the die bonder, but also have a negative impact on the maintenance and service life of the equipment. Therefore, in the design and manufacturing process of the die bonder, the radial runout accuracy of the linear bearing must be strictly controlled to ensure that the bonding head can rotate accurately and the chip is accurately placed. Summary of the invention

[0006] The purpose of the present invention is to provide an air bearing to solve the problem of low radial runout accuracy when a die bonder transfers a chip through a linear bearing in the prior art.

[0007] The technical solution of the present invention is: an air-floating bearing, comprising: a shell with an air-floating chamber built in, the shell being provided with a multi-layer air supply channel group interconnected with each other, the multi-layer air supply channel group being distributed along a first direction, the air supply channel group having a plurality of output ends evenly arranged around the air-floating chamber, the output end of the air supply channel group being connected to the air-floating chamber; a main shaft, rotatably connected in the air-floating chamber, the main shaft and the inner wall gap of the shell being matched, the main shaft being provided with a first air gallery, the shell being provided with a first negative pressure air duct, the first air gallery and the first negative pressure air duct being connected to form a first adsorption channel for adsorbing chips; at least one end face of the shell along the first direction is provided with an opening, the air supply channel group introduces compressed gas to fill the gap, the first adsorption channel is connected to the gap, and the compressed gas flows out from the end opening of the shell and / or the first negative pressure air duct.

[0008] Preferably, at least two layers of the air supply channel groups are distributed on both sides of the first air corridor and the first negative pressure air duct, and the output ends of the single-layer air supply channel groups are located on the same plane perpendicular to the first direction, and the output ends of the air supply channel groups are all arranged radially.

[0009] Preferably, the shell is provided with an air delivery pipe and an air delivery port, the air delivery pipe is connected with multiple layers of the air supply channel group along a first direction, the air delivery port is opened on the side wall of the shell, the air delivery port is connected with the air delivery pipe, and is used to transport compressed gas in the air delivery pipe, and the air delivery pipe is connected to the end face of at least one end of the shell.

[0010] Preferably, the shell is provided with a second negative pressure air duct, the main shaft is provided with a second air gallery, the second negative pressure air duct and the second air gallery are connected to form a second adsorption channel, the end of the second adsorption channel is adsorbed and connected with a suction nozzle, the first adsorption channel passes through the suction nozzle to adsorb the chip, the second adsorption channel is connected with the gap, and the second air gallery and the second negative pressure air duct are between at least two layers of air supply channel groups.

[0011] Preferably, there are two groups of air supply channel groups, and the two groups of air supply channel groups are respectively opened at positions close to two ends of the shell.

[0012] Preferably, the air supply channel group includes a plurality of air supply chambers, the input ends of the plurality of air supply chambers are connected to the air supply pipe, the output ends of the air supply chambers are connected to the air flotation chamber, and the plurality of air supply chambers are distributed in a circular array around the main axis.

[0013] Preferably, the air supply chamber includes a first chamber, a second chamber and a third chamber which are connected in sequence, the first chamber is connected to the air flotation chamber, the third chamber is connected to the outside, the third chamber is threadedly connected with a bolt, and the bolt is screwed with the third chamber to control the spatial volume of the air supply chamber, the second chamber is connected to the air pipe, and the diameter of the first chamber is smaller than the diameter of the second chamber.

[0014] Preferably, a first make way cavity and a second make way cavity are recessed in the inner wall of the shell, the first adsorption channel is communicated with the first make way cavity, and the second adsorption channel is communicated with the second make way cavity.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] The air supply channel group has multiple output ends evenly arranged around the air flotation chamber. This design ensures the uniformity of gas distribution in the air flotation chamber, helps to reduce the radial runout of the main shaft during rotation, and improves the rotation stability. The multi-layer air supply channels are distributed along the first direction, providing multi-level support for the main shaft, further increasing the support of the compressed gas to the main shaft, improving the air flotation effect, ensuring the uniformity of the gap between the main shaft and the shell, thereby enhancing the stability of the main shaft rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0018] Figure 1 This is a schematic structural diagram of an air bearing according to the present invention;

[0019] Figure 2 It is a schematic cross-sectional structural diagram of a first adsorption channel of an air bearing according to the present invention;

[0020] Figure 3 For the present invention Figure 2 A schematic cross-sectional structural diagram of AA of the structure of an air bearing described in the invention;

[0021] Figure 4 It is a schematic cross-sectional structural diagram of a second adsorption channel of an air bearing according to the present invention;

[0022] Figure 5 For the present invention Figure 4 A schematic cross-sectional view of the structure of the air bearing BB described in the embodiment;

[0023] Figure 6 It is a schematic cross-sectional structure diagram of an air supply channel group of an air bearing according to the present invention;

[0024] Figure 7 For the present invention Figure 6A schematic cross-sectional view of the CC structure of an air bearing structure as described above;

[0025] Figure 8 For the present invention Figure 6 A schematic cross-sectional view of the structure of the DD of an air bearing as described in the invention;

[0026] Fig. 9 It is a partial cross-sectional structural schematic diagram of 6 described in the present invention.

[0027] in: Figure 3 , Figure 5 , Figure 7 and Figure 8 Although it is a cross-sectional view, in order to show the structure more clearly, Figure 3 , Figure 5 , Figure 7 and Figure 8 A complete cross-sectional view of an air bearing.

[0028] Description of reference numerals:

[0029] 1. Shell; 11. Air flotation chamber; 12. Air supply channel group; 121. Air supply chamber; 1211. First chamber; 1212. Second chamber; 1213. Third chamber; 1214. Bolt; 13. First negative pressure air duct; 14. First give way chamber; 15. Second negative pressure air duct; 16. Second give way chamber; 17. Air delivery port; 18. Air delivery pipe; 181. Balance channel; 2. End cover; 3. Main shaft; 31. First air gallery; 32. First adsorption interface; 33. Second air gallery; 34. Second adsorption interface; 4. First adsorption channel; 5. Second adsorption channel; 6. Suction nozzle; 61. Adsorption hole. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. 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 making creative work are within the scope of protection of the present invention.

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] like Figures 1 to 8 As shown, an air-floating bearing is used to improve the radial runout accuracy of the bearing for transporting chips, including a shell 1 and a spindle 3. The shell 1 has an air-floating chamber 11 built in it. The spindle 3 and the shell 1 are in clearance fit. The spindle 3 is rotatably connected in the air-floating chamber 11. The shell 1 is provided with a multi-layer air supply channel group 12 along the first direction. The air supply channel group 12 has multiple output ends connected to the air-floating chamber 11. The compressed air is input into the air-floating chamber 11, so that the gap between the spindle 3 and the inner wall of the shell 1 along the first direction is approximately the same, thereby improving the radial runout accuracy of the air-floating bearing and reducing the error. It is worth noting that the first direction is the axial direction of the spindle 3.

[0034] like Figures 2 to 3 As shown, the main shaft 3 is provided with a first air gallery 31, and the shell 1 is provided with a first negative pressure air duct 13. The first air gallery 31 and the first negative pressure air duct 13 are connected to the first adsorption channel 4 for adsorbing chips. Specifically, both ends of the main shaft 3 are arranged to extend out of the shell 1 in the first direction, and one end of the main shaft 3 is used for transmission connection driving parts, such as a motor, etc. to provide power for the main shaft 3, so that the main shaft 3 rotates relative to the shell 1, and the bottom of the main shaft 3 extends out of the shell 1 for adsorbing chips. The main shaft 3 is threadedly connected with an end cap 2, and the screwing direction of the end cap 2 and the main shaft 3 is opposite to the rotation direction of the main shaft 3. The end cap 2 can always be fixed to the main shaft 3 when the main shaft 3 rotates. There is a gap between the end cap 2 and the upper end surface of the shell 1 to avoid friction between the end cap 2 and the shell 1 when the end cap 2 rotates.

[0035] In this embodiment, the first air gallery 31 is an "L"-shaped tube, one end of the first air gallery 31 is connected to the bottom of the main shaft 3, and the port serves as the first adsorption port of the first air gallery 31, and the other end of the first air gallery 31 is connected to the side wall of the main shaft 3, and the port serves as the first adsorption interface 32 of the first air gallery 31. Preferably, there are three first adsorption interfaces 32, all of which are connected to the first air gallery 31 to improve the adsorption effect of the first adsorption channel 4.

[0036] A first clearance cavity 14 is provided on the inner wall of the shell 1 at the same height as the first adsorption interface 32. The first clearance cavity 14 is an annular groove formed by the inward depression of the shell 1. One end of the first negative pressure air duct 13 is connected to the negative pressure device outside, and the other end is connected to the first clearance cavity 14. The first air gallery 31 is connected to the first negative pressure air duct 13 in the first clearance cavity 14. The space of the first clearance cavity 14 can reduce the influence of the negative pressure environment on the gap between the main shaft 3 and the shell 1 when the first adsorption channel 4 generates negative pressure to adsorb the chip, so as to ensure the radial runout accuracy of the main shaft 3.

[0037] like Figures 4 to 5 As shown, the spindle 3 is provided with a second air gallery 33, the shell 1 is provided with a second negative pressure air duct 15, and the bottom of the spindle 3 is detachably connected with a suction nozzle 6. The second air gallery 33 and the second negative pressure air duct 15 are connected to the second adsorption channel 5, and the second adsorption channel 5 adsorbs the suction nozzle 6. The present application uses suction nozzles 6 of different specifications when adsorbing chips of different models, and the suction nozzle 6 is easily replaced by the adsorption connection. The suction nozzle 6 is provided with an adsorption hole 61, and the adsorption hole 61 of the suction nozzle 6 is connected to the first air gallery 31 to adsorb the chip. A sealing ring is provided at the connection between the adsorption hole 61 and the first air gallery 31. The first section of the air gallery and the adsorption hole 61 can be sealed and connected to ensure that the adsorption effect of the first adsorption channel 4 on the chip is stable. Preferably, the suction nozzle 6 is built into the lower end of the spindle 3, and the end of the second air gallery 33 abuts against the upper end surface of the suction nozzle 6 to enhance the adsorption effect of the second adsorption channel 5 on the suction nozzle 6 and reduce the risk of the suction nozzle 6 falling off.

[0038] Specifically, the second air gallery 33 is an "L"-shaped tube, one end of the second air gallery 33 is connected to the bottom of the main shaft 3, and the port serves as the second adsorption port of the second air gallery 33, and the other end of the second air gallery 33 is connected to the side wall of the main shaft 3, and the port serves as the second adsorption interface 34 of the second air gallery 33. Preferably, there are three second adsorption interfaces 34, all of which are connected to the second air gallery 33 to improve the adsorption effect of the second adsorption channel 5.

[0039] A second clearance cavity 16 is provided on the inner wall of the shell 1 at the same height as the second adsorption interface 34. The second clearance cavity 16 is an annular groove formed by the inward depression of the shell 1. One end of the second negative pressure air duct 15 is connected to the external negative pressure equipment, that is, a negative pressure equipment simultaneously performs vacuum operation on the first negative pressure air duct 13 and the second negative pressure air duct 15. The other end of the second negative pressure air duct 15 is connected to the second clearance cavity 16, and the second air gallery 33 is connected to the second negative pressure air duct 15 in the second clearance cavity 16. The space of the second clearance cavity 16 can reduce the influence of the negative pressure environment on the gap between the main shaft 3 and the shell 1 when the second adsorption channel 5 generates a negative pressure adsorption chip, so as to ensure the radial runout accuracy of the main shaft 3. Preferably, the opening directions of the first adsorption interface 32 and the second adsorption interface 34 are set opposite to each other to further balance the influence on the rotation of the main shaft 3 during the vacuuming process. It is worth noting that the first adsorption interface 32 and the second adsorption interface 34 are at different heights along the first direction, and the opposite setting means that the two adsorption interfaces are set in two opposite directions on two planes perpendicular to the first direction.

[0040] The air supply channel group 12 introduces compressed air into the gap between the shell 1 and the main shaft 3 through its output end, and the main shaft 3 and the shell 1 are non-contact rotationally connected. In this embodiment, the air supply channel group 12 is two layers, and the air supply channel group 12 is distributed in the shell 1 along the first direction, wherein one air supply channel group 12 is located inside the shell 1 near the upper end surface, and the other air supply channel group 12 is located inside the shell 1 near the lower end surface, so as to inject compressed air into the parts of the main shaft 3 near both ends, so as to enhance the control of the main shaft 3 and further improve the accuracy of radial runout. The first give-way cavity 14 and the second give-way cavity 16 are both between the two air supply channel groups 12, that is, parts of the first adsorption channel 4 and the second adsorption channel 5 are both located between the two air supply channel groups 12.

[0041] like Figures 6 to 8 As shown, specifically, the shell 1 is provided with an air delivery port 17 and a plurality of air delivery pipes 18, the air delivery port 17 is connected to the air delivery pipe 18, and both layers of air supply channel groups 12 are connected to the air delivery pipe 18, and the air delivery port 17 is used to communicate with the compressor, and the compressor delivers compressed air to the air flotation chamber 11 through the air delivery port 17, the air delivery pipe 18 and the air supply channel group 12.

[0042] In this embodiment, there are five gas pipes 18, which are arranged along the first direction. The five gas pipes 18 are distributed in a circular array around the central axis of the main shaft 3. An annular cavity is opened in the shell 1 to connect the five gas pipes 18. The five gas pipes 18 are all connected to the two-layer gas supply channel group 12 to form a circulation channel for compressed gas inside the shell 1.

[0043] Preferably, the gas pipe 18 is connected to the top end face of the shell 1, so that the gas in the gas pipe 18 can flow out directly from the top of the shell 1, and the diameter of the gas pipe 18 near the top end is reduced to weaken the flow of compressed gas. The above arrangement can balance the pressure of the gas in the gas pipe 18 and reduce the situation where the compressed gas pressure in the gas pipe 18 is too high. The gap between the end cover 2 and the shell 1 can allow the compressed gas to flow out, and the outflowing compressed gas can keep the gap between the end cover 2 and the shell 1 uniform.

[0044] like Fig. 9 As shown, the single-layer air supply channel group 12 includes a plurality of air supply chambers 121, the input ends of the plurality of air supply chambers 121 are connected to the air delivery pipe 18, the output ends of the air supply chambers 121 are connected to the air flotation chamber 11, and the plurality of air supply chambers 121 are distributed in a circular array around the main axis 3. In this embodiment, the single-layer air supply channel group 12 has five air supply chambers 121, and the air supply chambers 121 are connected to the air delivery pipe 18 one by one.

[0045] Specifically, the air supply chamber 121 includes a first chamber 1211, a second chamber 1212, and a third chamber 1213 which are connected in sequence, and the first chamber 1211, the second chamber 1212, and the third chamber 1213 are arranged in sequence along the radial direction. The first chamber 1211 is connected to the air flotation chamber 11, and the third chamber 1213 is connected to the outside. The third chamber 1213 is threadedly connected with a bolt 1214, and the second chamber 1212 is connected to the air supply pipe 18. The feeding amount of the bolt 1214 and the third chamber 1213 is adjusted to control the space in the air supply chamber 121, adjust the size of the space in the air supply chamber 121, and control the air pressure of the compressed air in the air supply chamber 121, thereby controlling the pressure of each compressed air flowing from the air supply chamber 121 to the air flotation chamber 11. The diameter of the first chamber 1211 is smaller than that of the second chamber 1212 to further pressurize the compressed air. A plurality of evenly distributed air supply chambers 121 can adjust the gap between the housing 1 and the spindle 3, thereby adjusting the radial runout accuracy of the spindle 3 when transporting chips.

[0046] Preferably, the section of the gas pipe 18 near the top end surface of the shell 1 in the second chamber 1212 is a balancing channel 181, and the diameter of the balancing channel 181 is much smaller than the diameter of the gas pipe 18, so as to balance the air pressure while reducing the leakage of compressed air, so that the compressed gas can change with a smaller amplitude, ensuring that the compressed gas input into the flotation chamber 11 tends to be stable.

[0047] It is worth mentioning that the gaps mentioned in the foregoing text are many times, such as the gap between the housing 1 and the main shaft 3, and the gap between the end cover 2 and the housing 1. Since they are for adjusting the radial runout accuracy of the main shaft 3, the gaps are very narrow and cannot be clearly seen in the figure.

[0048] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. An air bearing, characterized in that: include: A shell (1) having an air flotation chamber (11) therein, the shell (1) being provided with a plurality of mutually connected air supply channel groups (12), the plurality of air supply channel groups (12) being distributed along a first direction, the air supply channel group (12) having a plurality of output ends evenly arranged around the air flotation chamber (11), the output ends of the air supply channel group (12) being in communication with the air flotation chamber (11); A main shaft (3) is rotatably connected in the air flotation chamber (11); the main shaft (3) and the inner wall gap of the shell (1) are matched to form a gap; the main shaft (3) is provided with a first air gallery (31); the shell (1) is provided with a first negative pressure air duct (13); the first air gallery (31) and the first negative pressure air duct (13) are connected to form a first adsorption channel (4) for adsorbing chips; At least one end face of the shell (1) along the first direction is arranged to be open, the air supply channel group (12) introduces compressed gas to fill the gap, the first adsorption channel (4) is connected to the gap, and the compressed gas flows out from the end opening of the shell (1) and / or the first negative pressure air duct (13).

2. An air bearing according to claim 1, characterized in that: At least two layers of the air supply channel groups (12) are distributed on both sides of the first air gallery (31) and the first negative pressure air duct (13), and the output ends of the single-layer air supply channel groups (12) are located on the same plane perpendicular to the first direction, and the output ends of the air supply channel groups (12) are all arranged radially.

3. An air bearing according to claim 2, characterized in that: The shell (1) is provided with an air delivery pipe (18) and an air delivery port (17); the air delivery pipe (18) is connected to the multiple layers of the air supply channel group (12) along a first direction; the air delivery port (17) is provided on the side wall of the shell (1); the air delivery port (17) is connected to the air delivery pipe (18) and is used to deliver compressed gas in the air delivery pipe (18); the air delivery pipe (18) is connected to the end surface of at least one end of the shell (1).

4. The air bearing according to claim 1, characterized in that: The shell (1) is provided with a second negative pressure air duct (15), the main shaft (3) is provided with a second air gallery (33), the second negative pressure air duct (15) and the second air gallery (33) are connected to form a second adsorption channel (5), the end of the second adsorption channel (5) is adsorbedly connected with a suction nozzle (6), the first adsorption channel (4) passes through the suction nozzle (6) to adsorb the chip, the second adsorption channel (5) is connected with the gap, and the second air gallery (33) and the second negative pressure air duct (15) are between at least two layers of air supply channel groups (12).

5. The air bearing according to claim 1, characterized in that: The air supply channel groups (12) are divided into two groups, and the two groups of air supply channel groups (12) are respectively opened at positions close to two ends of the shell (1).

6. An air bearing according to claim 3, characterized in that: The air supply channel group (12) comprises a plurality of air supply chambers (121), the input ends of the plurality of air supply chambers (121) being connected to the air supply pipe (18), the output ends of the air supply chambers (121) being connected to the air flotation chamber (11), and the plurality of air supply chambers (121) being distributed in a circular array around the main axis (3).

7. An air bearing according to claim 6, characterized in that: The air supply chamber (121) comprises a first chamber (1211), a second chamber (1212) and a third chamber (1213) which are connected in sequence, the first chamber (1211) being connected to the air flotation chamber (11), the third chamber (1213) being connected to the outside, the third chamber (1213) being threadedly connected with a bolt (1214), the bolt (1214) being screwed together with the third chamber (1213) to control the spatial volume of the air supply chamber (121), the second chamber (1212) being connected to the air supply pipe (18), the diameter of the first chamber (1211) being smaller than the diameter of the second chamber (1212).

8. The air bearing according to claim 4, characterized in that: The inner wall of the shell (1) is concavely provided with a first make way cavity (14) and a second make way cavity (16); the first adsorption channel (4) is in communication with the first make way cavity (14); and the second adsorption channel (5) is in communication with the second make way cavity (16).

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