Aerostatic bearing for chip bonding and bonding assembly

Abstract

The invention belongs to the technical field of chip bonding, and particularly relates to an aerostatic bearing for chip bonding, comprising: a housing, the side wall of which is provided with an air pipe joint and the middle of which is provided with a through accommodating cavity; the radial bearing is arranged in the accommodating cavity in a sleeving manner; the thrust bearing assembly comprises a first thrust bearing and a second thrust bearing, and the second thrust bearing is arranged above the radial bearing; the distance ring is arranged between the first thrust bearing and the second thrust bearing; the first cover plate is arranged above the first thrust bearing and is sequentially connected with the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing and the shell through connecting pieces; the second cover plate is arranged below the shell and is fixedly connected with the shell; wherein the first cover plate, the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing and the shell are respectively provided with gas channels which are communicated in sequence, and the gas pipe joints are communicated with the gas channels; the bearing capacity and rigidity are effectively improved, and the gas film stability is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip bonding, and in particular relates to a gas static pressure bearing and a bonding assembly for chip bonding. Background Art

[0002] With the continuous iteration and upgrading of semiconductor manufacturing and packaging technology, the chip bonding process has put forward higher and higher requirements for positioning accuracy and operational reliability. In order to meet the dual requirements of bonding quality and production cycle. In order to meet the dual requirements of bonding quality and production cycle, existing chip bonding equipment generally emphasizes keeping the chip and substrate accurately aligned while minimizing the time of a single operation. In order to achieve precise control of the motion state, it is crucial to reduce the mass and volume of the moving components: lighter moving parts are not only easier to layout in a limited equipment space, but also help to improve the dynamic response speed and meet the requirements of high-precision and high-efficiency repeated positioning. However, when the bearing size is limited due to the lightweighting of the entire machine, how to still obtain sufficient load-bearing capacity and air film stability within the reduced design space has become a major problem in existing technologies.

[0003] Traditional rolling bearings are prone to wear, vibration, and lubricant contamination in scenarios involving repetitive motion and high-precision control, and their size and mass are difficult to reduce. In contrast, aerostatic bearings, with their advantages of contactless support, oil-free operation, and low friction, are increasingly being used in microelectronics and semiconductor equipment. However, most existing aerostatic bearings utilize relatively simple pressure-equalizing grooves, leading to common problems such as insufficient air film bearing capacity, insufficient stiffness, and unstable flow.

[0004] For example, the patent document with publication number CN111927886A discloses a support method for AACMM high-precision joints based on hydrostatic air bearings. Two radial vent groups arranged with axial spacing are set on the thrust bearing. Each group contains multiple radial vents to form multiple air inlets. The structure is complex, which increases the difficulty of manufacturing and assembly. At the same time, the multiple air inlet structure also has certain problems of air flow instability and insufficient air film stability.

[0005] For example, the patent document with publication number CN115614386A discloses a small-hole gas static pressure radial bearing sleeve structure with a high-pressure air cavity, which adopts an "H"-type or "M"-type pressure equalizing groove structure. Although the pressure equalizing groove structure improves the bearing capacity to a certain extent, its geometric structure is fixed and the groove layout cannot be flexibly adjusted according to the load requirements. Therefore, it is difficult to maximize the bearing capacity and stiffness, and cannot meet the needs of chip bonding equipment for fine adjustment of air film performance under different working conditions.

[0006] Based on this, it is necessary to improve the defects existing in the prior art to overcome the shortcomings in practical application. SUMMARY

[0007] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the purposes of the present application is to at least solve one or more of the above-mentioned problems existing in the prior art, or in other words, one of the purposes of the present application is to provide a gas static pressure bearing and bonding assembly for chip bonding which meets one or more of the aforementioned needs.

[0008] In order to achieve the above-mentioned purposes of the application, the following technical solutions are adopted:

[0009] The present application provides a gas static pressure bearing for chip bonding, comprising:

[0010] A housing, the side wall of the housing is provided with a gas pipe joint, and the middle part of the housing is provided with a through accommodating cavity;

[0011] A radial bearing is sleeved in the accommodating cavity;

[0012] A thrust bearing assembly comprising a first thrust bearing and a second thrust bearing, the second thrust bearing is arranged above the radial bearing;

[0013] A distance ring is arranged between the first thrust bearing and the second thrust bearing;

[0014] A first cover plate is arranged above the first thrust bearing and is connected with the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing and the housing in sequence through a connecting piece;

[0015] A second cover plate is arranged below the housing and is tightly connected with the housing;

[0016] Wherein, the first cover plate, the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing and the housing are respectively provided with gas channels which are connected in sequence, and the gas pipe joint is connected with the gas channel.

[0017] As a preferred solution, the first thrust bearing and the second thrust bearing are respectively provided with a circumferential equalizing groove and a radial equalizing groove, and a plurality of radial equalizing grooves are arranged in array along both sides of the circumferential equalizing groove.

[0018] As a preferred solution, each radial equalizing groove comprises a first branch groove, a second branch groove and a third branch groove, the end of the first branch groove is connected with two second branch grooves arranged in divergent manner, and the end of each second branch groove is connected with two third branch grooves arranged in divergent manner.

[0019] As a preferred solution, the first thrust bearing and the second thrust bearing are symmetrically arranged on the upper and lower sides of the constant distance ring, and the first thrust bearing, the constant distance ring and the second thrust bearing are correspondingly provided with axial air passages.

[0020] As a preferred solution, the lower end of the first cover plate and the upper end of the radial bearing are respectively provided with radial gas grooves, which are connected with the axial air passages on the first thrust bearing or the second thrust bearing.

[0021] As a preferred solution, the radial bearing is provided with a cavity, and a plurality of radial air passages are arranged on both sides of the cavity.

[0022] As a preferred solution, an axial gas groove is arranged between the radial bearing and the shell, and the axial gas groove is connected with the radial air passages.

[0023] As a preferred solution, the radial bearing and the constant distance ring are respectively provided with exhaust holes.

[0024] As a preferred solution, the gas passages at the connecting positions of the first cover plate, the first thrust bearing, the constant distance ring, the second thrust bearing, the radial bearing and the shell are respectively provided with sealing members.

[0025] The application also provides a chip bonding assembly, which comprises the hydrostatic bearing according to any one of the above solutions and a spindle, the spindle is sleeved in the hydrostatic bearing, when the gas pipe joint of the hydrostatic bearing is connected with high-pressure gas, a gas film is formed through the gap between the spindle and the hydrostatic bearing to support the spindle, and the lower end of the spindle is connected with a bonding tool, so that the chip is bonded.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] The application provides a gas hydrostatic bearing for chip bonding, which can effectively improve the bearing capacity and stiffness, ensure the stability of the gas film, reduce the motion friction, has a compact and reasonable overall structure layout, a simple and efficient gas passage design, a simple manufacturing process and convenient assembly and maintenance, can significantly reduce the production cost, improve the long-term operation reliability, and is suitable for bonding of micro-nano high-precision chips.

[0028] The application provides a gas hydrostatic bearing for chip bonding, which optimizes the structure and distribution of the pressure equalizing groove, forms a more stable, continuous and high bearing capacity gas film support on the surface of the hydrostatic bearing, and meets the multiple requirements of light weight, high precision and reliability of the chip bonding equipment. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings of other embodiments can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0030] Figure 1 is a structural schematic diagram of the gas static pressure bearing of the embodiment of the present application;

[0031] Figure 2 is an exploded view of the gas static pressure bearing of the embodiment of the present application;

[0032] Figure 3 is a first perspective view of the gas static pressure bearing of the embodiment of the present application;

[0033] Figure 4 is a second perspective view of the gas static pressure bearing of the embodiment of the present application;

[0034] Figure 5 is a structural schematic diagram of the distance ring of the embodiment of the present application;

[0035] Figure 6 is a structural schematic diagram of the first thrust bearing of the embodiment of the present application;

[0036] Figure 7 is a structural schematic diagram of the radial bearing of the embodiment of the present application;

[0037] Figure 8 is a structural schematic diagram of the radial pressure equalizing groove of the embodiment of the present application;

[0038] Figure 9 is a sectional view of the cooperation relationship between the static pressure bearing and the main shaft of the embodiment of the present application;

[0039] Figure 10 is a partial structural schematic diagram of the axial view of the cooperation relationship between the static pressure bearing and the main shaft of the embodiment of the present application;

[0040] Figure 11 is a structural schematic diagram of the main shaft of the embodiment of the present application;

[0041] In the figure: 1 housing, 11 gas pipe joint, 12 containing cavity, 2 first cover plate, 21 radial gas groove, 22 mounting hole, 3 first thrust bearing, 31 radial pressure equalizing groove, 311 first branch groove, 312 second branch groove, 313 third branch groove, 32 circumferential pressure equalizing groove, 33 axial gas channel, 34 mounting hole, 4 distance ring, 41 axial gas channel, 42 exhaust hole, 43 mounting hole, 5 second thrust bearing, 6 radial bearing, 61 radial gas groove, 62 cavity, 63 radial gas channel, 64 axial gas groove, 65 exhaust hole, 7 second cover plate, 8 connecting piece, 9 sealing piece, 10 main shaft, S gas flow direction. DETAILED DESCRIPTION

[0042] In order to more clearly illustrate the embodiments of the present application, the specific embodiments of the present application will be described below with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained according to these drawings without creative labor, and other embodiments can also be obtained by those skilled in the art.

[0043] In the description of the embodiments of the present application, the terms "upper", "lower", "front", "back" and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only used to distinguish in the description, and have no special meaning.

[0044] According to some embodiments of the present application, please refer to Figures 1 to 8 As shown in the figure, a gas static pressure bearing for chip bonding is provided, which comprises a housing 1, a first cover plate 2, a thrust bearing assembly, a distance ring 4, a radial bearing 6 and a second cover plate 7. The side wall of the housing 1 is provided with a gas pipe joint 11. The middle part of the housing 11 is configured with a through containing cavity 12, and the radial bearing 6 is sleeved in the containing cavity 12. The thrust bearing assembly comprises a first thrust bearing 3 and a second thrust bearing 5, and the second thrust bearing 4 is arranged above the radial bearing 6. The distance ring 4 is arranged between the first thrust bearing 3 and the second thrust bearing 5. The first cover plate 2 is arranged above the first thrust bearing 3 and is connected with the first thrust bearing 3, the distance ring 4, the second thrust bearing 5, the radial bearing 6 and the housing 1 in sequence through the connecting piece 8. The second cover plate 7 is arranged below the housing 1 and is tightly connected with the housing 1. Among them, the first cover plate 2, the first thrust bearing 3, the distance ring 4, the second thrust bearing 5, the radial bearing 6 and the housing 1 are respectively provided with gas passages which are connected in sequence, and the gas pipe joint 11 is connected with the gas passages.

[0045] In some embodiments of the present application, the first thrust bearing 3 and the second thrust bearing 5 are respectively provided with a circumferential pressure equalizing groove 31 and a radial pressure equalizing groove 32, and a plurality of radial pressure equalizing grooves 31 are arranged along the two sides of the circumferential pressure equalizing groove 32. The circumferential pressure equalizing groove is arranged around the center hole of the first thrust bearing and the second thrust bearing, and organically connects each radial pressure equalizing groove, so that the gas can be more uniformly and efficiently diffused, and the carrying capacity and stability of the gas film are greatly improved.

[0046] Specifically, each radial pressure equalizing groove 31 respectively includes a first branch groove 311, a second branch groove 312 and a third branch groove 313, the end of the first branch groove 311 is connected to two second branch grooves 312 arranged in a diverging manner, and the end of each second branch groove 312 is connected to two third branch grooves 313 arranged in a diverging manner.

[0047] Further, the length of the first branch groove 311 is l0, the width is d0, the length of the second branch groove is l1, the width is d1, the length of the third branch groove is l2, the width is d2, and the included angle between each branch groove is γ; the length ratio of the second branch groove to the first branch groove is α1=l1 / l0, and the width ratio is β1=d1 / d0; the length ratio of the third branch groove to the second branch groove is α2=l2 / l1, and the width ratio is β2=d2 / d1.

[0048] Further, the following specifically explains the calculation process of the structural parameters: setting the total length of the flow channel as l_total, the end flow channel width d2 as the limit value allowed by the manufacturing process, and the dimensionless numbers α1, α2, β1 and β2 being known, the specific calculation process is as follows:

[0049] According to the width of the third branch groove, the width of each branch groove is calculated step by step: d1=d2 / β2, d0=d1 / β1; according to the total length of the radial pressure equalizing groove, the relationship formula of the length of each branch groove is established: l0+l1+l2=l_total, wherein l1=α1×l0, l2=α2×l1=α2×α1×l0.

[0050] Further, the length of each branch groove is calculated as follows:

[0051] l0=l_total / (1+α1+α1α2) l1=α1×l0 l2=α1×l1.

[0052] By the above method, the specific size of each branch groove can be accurately obtained, so as to realize the optimized layout of the radial pressure equalizing groove structure, make the gas entering the static pressure bearing uniformly diffuse on the working surface, and form a stable, continuous and high-carrying-capacity gas film.

[0053] In some embodiments of the present application, the first thrust bearing 3 and the second thrust bearing 5 are identical in structure and symmetrically arranged on the upper and lower sides of the spacer ring 4, and the first thrust bearing 3 and the second thrust bearing 5 are respectively provided with an axial gas passage 33 penetrating therethrough, and the spacer ring 4 is provided with an axial gas passage 41, and the axial gas passages on the first thrust bearing 3, the spacer ring 4 and the second thrust bearing 5 are sequentially connected in communication to ensure the circulation of gas.

[0054] Further, the spacer ring 4 is provided with an exhaust hole 42 to exhaust the gas entering above the hydrostatic bearing.

[0055] Further, the lower end of the first cover plate 2 is provided with a radial gas groove 21, and the upper end of the radial bearing 6 is correspondingly provided with a radial gas groove 61, and the radial gas groove 21 is connected in communication with the axial gas passage on the first thrust bearing 3, and the radial gas groove 61 is connected in communication with the axial gas passage of the second thrust bearing 5.

[0056] In some embodiments of the present application, the radial bearing 6 is provided with a cavity 62 penetrating therethrough, and a plurality of radial gas passages 63 are respectively provided on both sides of the cavity 62, and the plurality of radial gas passages 63 are sequentially arranged in uniform layers to improve the uniformity of gas flow, thereby ensuring the stable bearing capacity of the hydrostatic bearing.

[0057] Further, an axial gas groove 64 is provided between the radial bearing 6 and the housing 1, and the axial gas groove 64 is connected in communication with the radial gas passage 63 to ensure that the gas entering the radial bearing 6 through the housing 1 smoothly and uniformly enters the cavity 62 of the radial bearing.

[0058] Further, the radial bearing 6 is provided with an exhaust hole 65 to exhaust the gas entering the cavity 62 of the radial bearing.

[0059] In some embodiments of the present application, the gas passages at the connection between the first cover plate 2, the first thrust bearing 3, the spacer ring 4, the second thrust bearing 5, the radial bearing 6 and the housing 1 are respectively provided with a sealing member 9 to avoid gas leakage at the gap between the components and ensure the sealing performance of the hydrostatic bearing.

[0060] According to some embodiments of the present application, the hydrostatic bearing can effectively improve the bearing capacity and stiffness, ensure the stability of the gas film, reduce the motion friction, and the overall structure layout is compact and reasonable, the gas passage design is simple and efficient, the manufacturing process is simple, and the assembly and maintenance are convenient, which can significantly reduce the production cost, improve the long-term operation reliability, and is suitable for the bonding of micro-nano high-precision chips.

[0061] According to some embodiments of the present application, as Figures 9 to 11As shown, the chip bonding assembly further comprises a static pressure bearing and a spindle 10 sleeved in the static pressure bearing, when the gas pipe joint of the static pressure bearing is communicated with high pressure gas, a gas film is formed through the gap between the spindle 10 and the static pressure bearing to support the spindle 10, and the lower end of the spindle 10 is connected with a bonding tool, so that the chip is bonded.

[0062] Further, as Figure 3 and Figure 9 The gas flow direction is shown by the dashed line S in the figure, the radial bearing and the spindle form a radial gas film gap of 2-30 microns between them, so as to realize the accurate positioning and stable support of the spindle in the radial direction; the first and second thrust bearings are respectively installed on the upper and lower ends of the distance ring, and form an axial gas film gap of 2-30 microns between them and the spindle, so as to provide the axial positioning and carrying capacity of the spindle; the distance ring is located between the first and second thrust bearings, and is used for accurately controlling the axial gas film gap and ensuring the axial positioning stability of the spindle.

[0063] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "linking", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0064] The above only describes the preferred embodiments and principles of the present application in detail, and for those skilled in the art, according to the idea provided by the present application, the specific implementation manner will be changed, and these changes should also be regarded as the protection scope of the present application.

Claims

1. A gas hydrostatic bearing for chip bonding, characterized in that: include: A housing, wherein a side wall of the housing is provided with an air pipe joint, and a central portion of the housing is provided with a penetrating accommodating cavity; A radial bearing is sleeved in the accommodating cavity; A thrust bearing assembly, comprising a first thrust bearing and a second thrust bearing, wherein the second thrust bearing is arranged above the radial bearing; a distance ring, provided between the first thrust bearing and the second thrust bearing; a first cover plate, disposed above the first thrust bearing, and connected to the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing, and the housing in sequence through connecting members; a second cover plate, disposed below the housing and securely connected to the housing; The first cover plate, the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing and the housing are respectively provided with gas passages that are connected in sequence, and the gas pipe joint is connected to the gas passages.

2. The gas hydrostatic bearing for chip bonding according to claim 1, characterized in that: The first thrust bearing and the second thrust bearing are respectively provided with a circumferential pressure equalizing groove and the radial pressure equalizing groove, and a plurality of radial pressure equalizing grooves are arranged in an array along both sides of the circumferential pressure equalizing groove.

3. The gas hydrostatic bearing for chip bonding according to claim 2, characterized in that: Each of the radial pressure-equalizing grooves includes a first branch groove, a second branch groove and a third branch groove. The end of the first branch groove is connected to two divergently arranged second branch grooves, and the end of each of the second branch grooves is connected to two divergently arranged third branch grooves.

4. The gas static pressure bearing for chip bonding according to claim 1, characterized in that: The first thrust bearing and the second thrust bearing are symmetrically arranged on the upper and lower sides of the distance ring, and axial air passages are correspondingly provided through the first thrust bearing, the distance ring and the second thrust bearing.

5. The gas static pressure bearing for chip bonding according to claim 4, characterized in that: The lower end of the first cover plate and the upper end of the radial bearing are respectively provided with radial gas grooves, and the radial gas grooves are connected to the axial air passages on the first thrust bearing or the second thrust bearing.

6. The gas hydrostatic bearing for chip bonding according to claim 1, characterized in that: The radial bearing is provided with a cavity passing through, and a plurality of radial air passages are respectively provided passing through both sides of the cavity, and the plurality of radial air passages are sequentially and evenly arranged in layers.

7. The gas hydrostatic bearing for chip bonding according to claim 6, characterized in that: An axial gas groove is provided between the radial bearing and the housing, and the axial gas groove is communicated with the radial air passage.

8. The gas hydrostatic bearing for chip bonding according to claim 1, characterized in that: The radial bearing and the distance ring are respectively provided with exhaust holes.

9. The gas hydrostatic bearing for chip bonding according to claim 1, characterized in that: Gas passages at the connection points between the first cover plate, the first thrust bearing, the distance ring, the second thrust bearing, the radial bearing and the housing are respectively provided with sealing members.

10. A chip bonding assembly, characterized in that: It comprises a hydrostatic bearing and a main shaft as described in any one of claims 1 to 9, wherein the main shaft is sleeved in the hydrostatic bearing, and when the air pipe joint of the hydrostatic bearing is connected to high-pressure gas, an air film is formed through the gap between the main shaft and the hydrostatic bearing to support the main shaft, and the lower end of the main shaft is connected to a bonding tool to achieve bonding of the chip.

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