Air bearing for wafer thinning machine

Abstract

The utility model discloses a wafer thinning machine is with air bearing, including fixed part, including the outer ring, lower inner ring and lower end cover, lower inner ring is assembled in the bottom of outer ring and is fixedly connected through lower end cover, and lower inner ring is used for with the fixed platform of wafer thinning machine, rotating part, including the inner ring, upper inner ring and upper end cover, the inner ring is assembled in the inside of outer ring, and upper inner ring is assembled in the top of outer ring and is fixedly connected through upper end cover, air passage, including the upper air groove of setting in the top of inner ring, the lower air groove of bottom and the communicating groove of intercommunication upper air groove and lower air groove. The utility model has the beneficial effects that: the rigidity and load capacity of bearing platform are promoted by large -size inner ring and multiple throttle hole design, are applicable to high -precision wafer thinning, gas film lubrication and ceramic inner ring 400 significantly reduce friction loss, and bearing life is promoted to 3 times or more than traditional mechanical bearing, and external air path system realizes air pressure dynamic regulation, and ensures the consistency and surface quality of wafer processing.

Description

Technical Field

[0001] This utility model relates to air bearings, and more particularly to an air bearing for a wafer thinning machine. Background Technology

[0002] In the semiconductor chip manufacturing industry, wafer thinning processes place extremely high demands on the stability, rigidity, and motion precision of the supporting stage. Traditional wafer thinning machines mostly use mechanical spindles or split-type air bearings as the stage drive structure, but these have significant drawbacks in practical applications:

[0003] Limitations of mechanical spindles:

[0004] Mechanical shafts rely on the precise fit of shaft components, but due to limitations in machining accuracy, frictional heat is easily generated between the shaft and bearings. During long-term operation, this frictional heat can lead to shaft annealing, accelerated wear, and even equipment failure. Furthermore, the rigidity of mechanical bearings is insufficient to meet the demands of high-speed thinning processes, and vibrations are easily generated during operation, directly affecting the surface finish of the wafer.

[0005] Disadvantages of split-type air bearings:

[0006] While split-type air-bearing turntables reduce friction through air film lubrication, their small load-bearing area and dispersed structure lead to a significant decrease in overall rigidity. Furthermore, the assembly precision requirements for multiple components are extremely high; even minor errors can cause uneven air film distribution, exacerbating bearing vibration and sway, making it difficult to ensure consistency in wafer processing. In addition, the rigidity of traditional air-bearing bearings is only a fraction of that of mechanical bearings, making them unsuitable for high-load, high-speed operating conditions.

[0007] Challenges of gas path control and sealing:

[0008] Existing air bearings suffer from a simplistic air passage design and uneven distribution of throttling orifices, which can easily lead to fluctuations in film pressure and affect motion stability. Furthermore, imperfect sealing structures can cause gas leakage, further weakening the bearing's stability and lifespan. The external air system lacks dynamic adjustment capabilities, making it difficult to achieve real-time matching of air pressure and load, thus exacerbating the impact risk during bearing start-up and shutdown.

[0009] To address the aforementioned issues, the industry urgently needs an air bearing solution that combines high rigidity, high stability, and long lifespan. This invention proposes an air bearing suitable for wafer thinning machines by optimizing the integrated structure, sealing design, and air path control of the air bearing. It aims to solve the core pain points of traditional technologies, such as high frictional loss, high assembly precision requirements, and insufficient rigidity, providing reliable support for high-precision thinning of semiconductor wafers. Utility Model Content

[0010] The main technical problem solved by this utility model is to provide an air bearing for a wafer thinning machine, thereby solving one or more of the above-mentioned prior art problems.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: an air bearing for a wafer thinning machine, the innovation of which lies in: including...

[0012] The fixed part includes an outer ring, a lower inner ring, and a lower end cover. The lower inner ring is assembled to the bottom of the outer ring and fixedly connected by the lower end cover. The lower inner ring is used to fix the wafer thinning machine to the machine base.

[0013] The rotating part includes an inner ring, an upper inner ring, and an upper end cap. The inner ring is assembled inside the outer ring, and the upper inner ring is assembled on the top of the outer ring and fixedly connected by the upper end cap.

[0014] The inclined mating structure has an outer ring inner sidewall with a lower slope, a connecting surface and an upper slope distributed from bottom to top. The lower slope and the upper slope are symmetrically arranged relative to the connecting surface. The lower inner ring outer sidewall matches the lower slope and the upper inner ring outer sidewall matches the upper slope.

[0015] A gap structure is provided, wherein a gap is formed between the top of the lower inner ring and the bottom of the upper inner ring;

[0016] The ring groove fitting structure has a lower ring groove at the top of the lower inner ring and an upper ring groove at the bottom of the upper inner ring. The top and bottom of the inner ring are respectively fitted with the lower ring groove and the upper ring groove.

[0017] The air passage includes an upper air trough at the top of the inner ring, a lower air trough at the bottom, and a connecting trough connecting the upper air trough and the lower air trough.

[0018] In some embodiments, the lower and upper slopes of the inner sidewall of the outer ring are continuous inclined surfaces with an inclination angle of 5° to 15°, and the connecting surface is a vertical plane.

[0019] In some embodiments, the air passage further includes a plurality of throttling orifices evenly distributed in the circumferential direction of the inner ring, the throttling orifices being connected to the upper air slot and the lower air slot, and the diameter of the throttling orifices being 2.0~3.0mm.

[0020] In some embodiments, multiple sealing structures are provided between the outer ring and the inner ring, including sealing grooves and corresponding sealing rings provided at both ends of the inner ring, to form an equivalent annular slit.

[0021] In some embodiments, the outer diameter of the inner ring is 250~300mm, and the gap between the outer ring and the inner ring is 0.01~0.05mm.

[0022] In some implementations, the number of throttling orifices is 24, which are evenly distributed along the inner circumference.

[0023] In some embodiments, an external air path control system is also included, which includes an air filter, a solenoid valve, and a solenoid proportional valve for precisely controlling air delivery to achieve bearing start-stop and motion stability.

[0024] The beneficial effects of this utility model are: high rigidity and stability: the large-size inner ring and multi-throttling hole design improve the rigidity and load-bearing capacity of the bearing stage, making it suitable for high-precision wafer thinning; low friction and long life: air film lubrication and ceramic inner ring 400 significantly reduce friction loss, increasing the bearing life to more than 3 times that of traditional mechanical bearings; precision control: the external air circuit system realizes dynamic air pressure adjustment, ensuring the consistency and surface quality of wafer processing. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0026] Figure 1 This is a schematic diagram of the structure of an air bearing for a wafer thinning machine according to this utility model.

[0027] Figure 2 This is a cross-sectional structural diagram of an air bearing for a wafer thinning machine according to this utility model.

[0028] Figure 3 This is a schematic diagram of the outer ring structure of an air bearing for a wafer thinning machine according to this utility model.

[0029] Figure 4 This is a schematic diagram of the lower inner ring of an air bearing for a wafer thinning machine according to this utility model.

[0030] Figure 5 This is a schematic diagram of the structure of the lower end cover of an air bearing for a wafer thinning machine according to this utility model.

[0031] Figure 6 This is a schematic diagram of the inner ring structure of an air bearing for a wafer thinning machine according to this utility model.

[0032] Figure 7 yes Figure 6 A schematic diagram of the structure viewed from below.

[0033] Figure 8 This is a schematic diagram of the upper inner ring of an air bearing for a wafer thinning machine according to this utility model.

[0034] Figure 9 This is a schematic diagram of the structure of the upper end cover of an air bearing for a wafer thinning machine according to this utility model. Detailed Implementation

[0035] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0036] like Figures 1 to 9 As shown, the air bearing for the wafer thinning machine of this utility model mainly includes the following structure:

[0037] Fixed part:

[0038] Outer ring 100: Made of high-strength aluminum alloy, its inner sidewall is provided with a lower slope surface 101, a connecting surface 102 and an upper slope surface 103 distributed from bottom to top; the lower slope surface 101 and the upper slope surface 103 are symmetrically arranged inclined surfaces with an inclination angle of 10°, and the connecting surface 102 is a vertical plane.

[0039] Lower inner ring 200: It is assembled at the bottom of the outer ring 100. Its outer side wall is machined into a slope that matches the lower slope surface 101. It is fixedly connected to the lower end cover 300 by bolts. The lower end cover 300 further locks the outer ring 100 and the lower inner ring 200. The lower inner ring 200 is fixed to the machine base of the wafer thinning machine through a flange structure.

[0040] Rotating part:

[0041] Inner ring 400: Made of ceramic material, with an outer diameter of 280mm, it is assembled inside the outer ring 100. It has an upper air groove 401 and a lower air groove 402 at its top and bottom, respectively, and they are connected by a connecting groove 403. The inner ring 400 has 24 throttling holes evenly distributed around its circumference, with a diameter of 2.5mm, for uniformly distributing airflow.

[0042] Upper inner ring 500: It is assembled on the top of the outer ring 100, and its outer side wall matches the upper slope surface 103 and is fixed by the upper end cover 600; the bottom of the upper inner ring 500 is provided with an upper ring groove 501, which cooperates with the bottom of the inner ring 400; the top of the lower inner ring 200 is provided with a lower ring groove 201, which cooperates with the top of the inner ring 400 to form a stable ring groove cooperation structure.

[0043] Gap structure: The gap between the top of the lower inner ring 200 and the bottom of the upper inner ring 500 is 0.03mm to ensure that there is no contact friction between the rotating part and the fixed part.

[0044] Sealing structure: The inner ring 400 has sealing grooves on both sides and a built-in fluororubber sealing ring, forming multiple equivalent annular slits with the outer ring 100, which effectively prevents gas leakage and improves airtightness.

[0045] Air passage and air path control: Compressed air enters the lower air groove 402 of the inner ring 400 through the air inlet of the lower inner ring 200, is transported to the upper air groove 401 through the connecting groove 403, and is then evenly distributed to the gap between the outer ring 100 and the inner ring 400 through the throttling orifice to form an air film lubrication.

[0046] External air circuit control system: includes air filter, solenoid valve, and solenoid proportional valve. The solenoid proportional valve dynamically adjusts the air pressure according to the load to ensure smooth start and stop of the bearing; the air filter filters impurities to prevent contamination of the air passage.

[0047] The working principle of this technical solution is as follows:

[0048] Start-up phase: The external air circuit control system is started. After being purified by the air filter, the compressed air enters the air inlet of the lower inner ring 200 through the solenoid valve. The airflow flows through the lower air groove 402, the connecting groove 403 and the upper air groove 401 in sequence, and is evenly sprayed out through 24 throttling holes, forming a stable air film between the outer ring 100 and the inner ring 400.

[0049] During operation: The air film completely separates the inner ring 400 from the fixed part. The inner ring 400 achieves contactless rotation under the support of the air film, driving the upper inner ring 500 and the wafer carrier stage to rotate at high speed. The electromagnetic proportional valve adjusts the air pressure in real time to ensure that the air film thickness is constant (0.01~0.05mm) and avoids vibration and sway.

[0050] Stopping phase: The solenoid valve shuts off the air supply, the air film gradually disappears, and the inner ring 400 makes flexible contact with the outer ring 100 through the sealing ring to avoid rigid impact.

[0051] The advantages of this technical solution are:

[0052] High rigidity and stability: The large inner ring (250~300mm) and multiple throttling holes enhance the rigidity and load-bearing capacity of the stage, making it suitable for high-precision wafer thinning.

[0053] Low friction and long life: Air film lubrication and ceramic inner ring 400 significantly reduce friction loss, increasing bearing life to more than 3 times that of traditional mechanical bearings.

[0054] Precision control: The external air supply system enables dynamic adjustment of air pressure to ensure consistency and surface quality in wafer processing.

[0055] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. An air bearing for a wafer thinning machine, characterized in that: include The fixed part includes an outer ring (100), a lower inner ring (200) and a lower end cover (300). The lower inner ring (200) is assembled to the bottom of the outer ring (100) and fixedly connected by the lower end cover (300). The lower inner ring (200) is used to fix to the machine base of the wafer thinning machine. The rotating part includes an inner ring (400), an upper inner ring (500) and an upper end cap (600). The inner ring (400) is fitted inside the outer ring (100), and the upper inner ring (500) is fitted to the top of the outer ring (100) and fixedly connected by the upper end cap (600). The inclined mating structure has an inner wall of the outer ring (100) with a lower slope (101), a connecting surface (102) and an upper slope (103) arranged sequentially from bottom to top. The lower slope (101) and the upper slope (103) are symmetrically arranged with respect to the connecting surface (102). The outer wall of the lower inner ring (200) matches the lower slope (101), and the outer wall of the upper inner ring (500) matches the upper slope (103). A gap structure is provided, wherein a gap is formed between the top of the lower inner ring (200) and the bottom of the upper inner ring (500); The ring groove fitting structure has a lower ring groove (201) at the top of the lower inner ring (200) and an upper ring groove (501) at the bottom of the upper inner ring (500). The top and bottom of the inner ring (400) are respectively fitted with the lower ring groove (201) and the upper ring groove (501). The air passage includes an upper air groove (401) at the top of the inner ring (400), a lower air groove (402) at the bottom, and a connecting groove (403) connecting the upper air groove (401) and the lower air groove (402).

2. The air bearing for a wafer thinning machine according to claim 1, characterized in that: The lower slope (101) and upper slope (103) of the inner sidewall of the outer ring (100) are both continuous inclined surfaces with an inclination angle of 5° to 15°, and the connecting surface (102) is a vertical plane.

3. The air bearing for a wafer thinning machine according to claim 1, characterized in that: The air passage also includes a plurality of throttling holes evenly distributed around the inner ring (400), the throttling holes being connected to the upper air groove (401) and the lower air groove (402), and the diameter of the throttling holes being 2.0 to 3.0 mm.

4. The air bearing for a wafer thinning machine according to claim 1, characterized in that: The outer ring (100) and the inner ring (400) are provided with multiple sealing structures, including sealing grooves and corresponding sealing rings at both ends of the inner ring (400) to form an equivalent annular slit.

5. An air bearing for a wafer thinning machine according to claim 1, characterized in that: The outer diameter of the inner ring (400) is 250-300 mm, and the gap between the outer ring (100) and the inner ring (400) is 0.01-0.05 mm.

6. An air bearing for a wafer thinning machine according to claim 3, characterized in that: The number of throttling orifices is 24, which are evenly distributed along the circumference of the inner ring (400).

7. An air bearing for a wafer thinning machine according to claim 1, characterized in that: The air bearing also includes an external air circuit control system, which includes an air filter, a solenoid valve, and a solenoid proportional valve for precisely controlling air delivery to achieve bearing start-up, shutdown, and motion stability.

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