A polishing head and a polishing apparatus

Abstract

The application provides a polishing head and a polishing device, and belongs to the technical field of semiconductor manufacturing. The polishing head comprises a base (1), a supporting part (2) arranged on a first end surface of the base (1), a cavity between the supporting part (2) and the base (1), a mounting plate (3) fixedly connected with the supporting part (2), the mounting plate (3) separating the cavity into a first cavity and a second cavity, a ventilation hole (301) being arranged on the mounting plate (3), a ventilation hole cover (4) movably connected with the mounting plate (3), the orthographic projection of the ventilation hole cover (4) on the mounting plate (3) covering an upper opening of the ventilation hole (301), at least two driving assemblies (5) mounted on the mounting plate (3), and at least two pressing discs (6) mounted on the driving assemblies (5), the lower surface of the pressing disc (6) abutting against the base (1). The technical scheme of the application can effectively improve the pressure distribution of the polishing head in different areas and meet the pressure requirement in the polishing process.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a polishing head and polishing equipment. Background Technology

[0002] Under the requirement of shallow damage layer, the removal of surface particle defects of large-size silicon wafers such as 12 inches is usually achieved by using an airbag polishing head. The entire process of grasping, polishing and releasing the silicon wafer is realized by changing positive and negative air pressure, and the final single-sided polishing (FP) process is completed.

[0003] Traditional single-chamber polishing heads, employing a rubber-based sealing structure and a single pneumatic pipeline system, suffer from two major technical bottlenecks: firstly, there is a significant deviation in the amount of material removed during polishing between the center and edge areas of the silicon wafer; secondly, it is impossible to dynamically adjust the pressure in different areas of the silicon wafer based on the flatness and morphology of the incoming material, making it difficult to control the amount of material removed during polishing in each area. Although multi-chamber structures can improve pressure distribution, they require modifications to the equipment's pneumatic pipeline system, resulting in higher costs. Summary of the Invention

[0004] This invention provides a polishing head and polishing equipment, which can effectively improve the pressure distribution of the polishing head in different areas and meet the pressure requirements in the polishing process.

[0005] To achieve the above objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0006] A polishing head, comprising:

[0007] Base;

[0008] A support portion is disposed on the first end face of the substrate, and a cavity is formed between the support portion and the substrate. The cross-section of the support portion is annular.

[0009] An mounting plate is installed inside the chamber and is fixedly connected to the support. The mounting plate divides the chamber into a first chamber and a second chamber. The first chamber is located above the second chamber. Ventilation holes are provided on the mounting plate.

[0010] The vent cover is movably connected to the mounting plate, and the orthographic projection of the vent cover on the mounting plate covers the upper opening of the vent.

[0011] At least two drive components are mounted on the mounting plate;

[0012] At least two pressure plates are mounted on the drive assembly. Each pressure plate corresponds to one drive assembly. The drive assembly is used to drive the pressure plates to move in the vertical direction, which is perpendicular to the horizontal plane. The lower surface of the pressure plate abuts against the base.

[0013] In some embodiments, the driving component includes:

[0014] Cylinder head, cylinder barrel, piston, and piston support column;

[0015] The first end of the cylinder head is mounted on the mounting plate;

[0016] The cylinder barrel is located in the second chamber and is fixedly connected to the second end of the cylinder head. A guide portion penetrating the bottom surface of the cylinder barrel is provided at the bottom of the cylinder barrel.

[0017] There is a receiving space between the cylinder head and the cylinder barrel. The piston is disposed in the receiving space, and the edge of the piston is in close contact with the inner wall of the cylinder barrel. The piston divides the receiving space into a first receiving space and a second receiving space. The first receiving space is connected to the first chamber.

[0018] The first end of the piston support column is fixedly connected to the piston, and the second end of the piston support column passes through the guide and extends out of the cylinder barrel, and is fixedly connected to the pressure plate.

[0019] In some embodiments, the second end of the cylinder head is provided with at least two first threaded holes of different diameters, and the cylinder barrel is provided with threads that match the first threaded holes.

[0020] In some embodiments, the vent cover includes:

[0021] Cover, connecting rod and limiting part;

[0022] The mounting plate has a first mounting hole, and the connecting rod passes through the first mounting hole. One end of the connecting rod is connected to the cover, and the other end is connected to the limiting part.

[0023] The orthographic projection of the cover onto the mounting plate covers the upper opening of the vent hole;

[0024] The outer diameter of the limiting part is larger than the diameter of the first mounting hole.

[0025] In some embodiments, the axis of the vent is at a predetermined angle to the horizontal plane.

[0026] In some embodiments, the edge of the mounting plate is inserted into the inner wall of the support, the mounting plate has a second threaded hole, the support has a second mounting hole, the second mounting hole and the second threaded hole are coaxially arranged, and the fastening bolt passes through the second mounting hole and is screwed into the second threaded hole.

[0027] In some embodiments, a rubber ring is provided between the mounting plate and the support.

[0028] In some embodiments, at least two drive components are evenly distributed on the mounting plate.

[0029] In some embodiments, the weight of the vent cap is less than a preset value.

[0030] This invention also provides a polishing apparatus, including the polishing head described above.

[0031] The beneficial effects of this invention are:

[0032] In this embodiment, the polishing head is provided with at least two driving components and a pressure plate. In this way, by adjusting the number and distribution of the driving components and the magnitude of the force they exert on the pressure plate, the pressure distribution in each area of ​​the polishing head can be controlled, thereby controlling the amount of material removed from different areas of the silicon wafer during the polishing process and achieving control over the flatness of the silicon wafer. Attached Figure Description

[0033] Figure 1 A schematic diagram showing the structure of a traditional single-pressure polishing head, an adsorption pad, and a silicon wafer;

[0034] Figure 2 A schematic diagram illustrating the traditional single air pressure polishing head and adsorption pad gripping a silicon wafer;

[0035] Figure 3 A schematic diagram illustrating the polishing / release of silicon wafers using a traditional single air pressure polishing head and an adsorption pad;

[0036] Figure 4 A schematic diagram showing the structure of the polishing head, adsorption pad, and silicon wafer according to an embodiment of the present invention;

[0037] Figure 5 A schematic diagram illustrating the polishing head and adsorption pad gripping a silicon wafer according to an embodiment of the present invention;

[0038] Figure 6 A schematic diagram illustrating the polishing head and adsorption pad polishing / releasing of a silicon wafer according to an embodiment of the present invention;

[0039] Figure 7 This is a top view showing the polishing head according to an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0041] Related technical introduction:

[0042] like Figure 1 As shown, the traditional single-pressure airbag type FP polishing head is mainly composed of a metal support ring 01 and a rubber base 02, and a combined adsorption pad 03 is attached to its surface. The adsorption pad 03 is in direct contact with the silicon wafer 05 to be polished.

[0043] During the work process: 1) Grabbing phase: such as Figure 2 As shown, by applying negative pressure to chamber 04, the silicon wafer 05 is gripped by the synergistic effect of negative pressure adsorption and surface tension; 2) Polishing / unloading stage: as shown Figure 3 As shown, positive pressure is applied to chamber 04. Due to the use of single-pressure control, the air pressure distribution within chamber 04 is uniform, resulting in the same air pressure force acting on all parts of the rubber substrate 02 (the pad is the polishing pad). However, due to the tension (reaction force) of the support ring 01, the deformation at the rubber edge is significantly less than that in the central area. This structural characteristic causes a difference in the net air pressure force between the center and the edge, ultimately leading to a non-uniform distribution of the amount of material removed from the silicon wafer 05 from the center to the edge. It is worth noting that the initial morphological differences of the silicon wafer 05 further exacerbate this non-uniformity of material removal, thereby affecting the controllability of the FP polishing process.

[0044] To address the aforementioned technical problems, embodiments of the present invention provide a polishing head and polishing equipment, which can effectively improve the pressure distribution of the polishing head in different areas and meet the pressure requirements in the polishing process.

[0045] like Figure 4-7 As shown, an embodiment of the present invention provides a polishing head, comprising:

[0046] 1. Base, 2. Support, 3. Mounting plate, 4. Vent cover, 5. At least two drive components, and 6. At least two pressure plates.

[0047] In some optional examples, the base 1 may be made of rubber, and the support 2 may be made of metal.

[0048] The support part 2 is disposed on the first end face of the base 1, and there is a cavity between the support part 2 and the base 1. The cross-section of the support part 2 is annular.

[0049] Mounting plate 3 is installed in the chamber and is fixedly connected to support part 2. Mounting plate 3 divides the chamber into a first chamber and a second chamber. The first chamber is located above the second chamber. Ventilation hole 301 is provided on mounting plate 3.

[0050] In some specific examples, the edge of the mounting plate 3 is inserted into the inner wall of the support part 2. The mounting plate 3 has a second threaded hole 302, and the support part 2 has a second mounting hole. The second mounting hole and the second threaded hole 302 are coaxially arranged. The fastening bolt 7 passes through the second mounting hole and is screwed into the second threaded hole 302.

[0051] In some embodiments, a rubber ring 8 is provided between the mounting plate 3 and the support portion 2.

[0052] To ensure airtightness, a rubber ring 8 can be installed at the connection between the support 2 and the mounting plate 3 to seal the gap at the connection.

[0053] The vent cover 4 is movably connected to the mounting plate 3, and the orthographic projection of the vent cover 4 on the mounting plate 3 covers the upper opening of the vent 301.

[0054] At least two drive components 5 are installed on the mounting plate 3.

[0055] At least two pressure plates 6 are mounted on the drive assembly 5. The pressure plates 6 correspond one-to-one with the drive assembly 5. The drive assembly 5 is used to drive the pressure plates 6 to move in the vertical direction, which is perpendicular to the horizontal plane. The lower surface of the pressure plate 6 abuts against the base 1.

[0056] In some specific examples, the area of ​​each pressure plate 6 is the same.

[0057] Here, the working principle of the polishing head in this embodiment of the invention is explained as follows:

[0058] like Figure 5 As shown, when the polishing head needs to grasp the silicon wafer, the polishing machine introduces negative pressure into the chamber, causing the lightweight vent cover 4 to be sucked up. The vent 301 on the mounting plate 3 opens, connecting the first and second chambers, and the substrate 1 is concave under the negative pressure. At this time, the pressure plate 6 still abuts against the substrate 1 due to gravity, and its large area can limit the substrate 1, preventing excessive deformation of the substrate 1 under negative pressure and thus avoiding breakage and failure.

[0059] like Figure 6 As shown, when the polishing head needs to apply pressure for polishing or release the silicon wafer, the polishing machine introduces positive pressure into the chamber. The vent hole 301 on the mounting plate 3 is sealed by the vent cover 4 to prevent air pressure leakage. Each independent drive component 5 drives the pressure plate 6 downward under the action of gas pressure, thereby converting the air pressure into force. The force is transmitted to the substrate 1 through the pressure plate 14, supporting the substrate 1 and realizing regional precise control of the polishing force, thereby obtaining a silicon wafer with the target flatness morphology.

[0060] In this embodiment, the polishing head is provided with at least two driving components and a pressure plate. In this way, the pressure distribution of each area on the polishing head can be controlled by adjusting the distribution of the driving components and the magnitude of the force applied by the driving pressure plate, thereby controlling the amount of material removed from different areas of the silicon wafer during the polishing process and achieving control over the flatness of the silicon wafer.

[0061] like Figure 4As shown, in some embodiments, the drive assembly 5 includes: a cylinder head 501, a cylinder barrel 502, a piston 503, and a piston support column 504; wherein, the first end of the cylinder head 501 is mounted on the mounting plate 3; the cylinder barrel 502 is disposed in the second chamber and fixedly connected to the second end of the cylinder head 501, and the bottom of the cylinder barrel 502 is provided with a guide portion 5021 penetrating the bottom surface of the cylinder barrel 502; there is an accommodating space between the cylinder head 501 and the cylinder barrel 502, the piston 503 is disposed in the accommodating space, and the edge of the piston 503 is in close contact with the inner wall of the cylinder barrel 502, the piston 503 divides the accommodating space into a first accommodating space and a second accommodating space, the first accommodating space communicating with the first chamber; the first end of the piston support column 504 is fixedly connected to the piston 503, the second end of the piston support column 504 passes through the guide portion 5021 and extends out of the cylinder barrel 502, and is fixedly connected to the pressure plate 6.

[0062] It should be noted that a through hole is provided at the center of the first end of the cylinder head 501. Therefore, the first accommodating space can communicate with the first chamber. In this way, the air pressure from the polishing machine can be transmitted to the piston 503 through the through hole.

[0063] like Figure 6 As shown, when the polishing head needs to apply pressure for polishing or release the silicon wafer, the polishing machine introduces positive pressure into the chamber. The vent hole 301 on the mounting plate 3 is sealed by the vent cover 4. The first accommodating space is connected to the first chamber. Therefore, the piston 503 in the drive assembly 5 moves downward under the action of air pressure, thereby converting the air pressure into a force. This force is transmitted to the substrate 1 through the piston support column 504 and the pressure plate 14, supporting the substrate 1 and achieving precise regional control of the polishing force, thereby obtaining a silicon wafer with the target flatness morphology.

[0064] In some embodiments, the second end of the cylinder head 501 is provided with at least two first threaded holes of different diameters, and the cylinder barrel 502 is provided with threads that match the first threaded holes.

[0065] In other words, in this embodiment of the invention, each cylinder head 501 may be provided with multiple threaded connection ports (first threaded holes) of different diameters to accommodate cylinder barrels 502 of different sizes (diameters). The cylinder barrel 502 is screwed into the first threaded hole on the cylinder head 501 via threads.

[0066] It should be noted that the basic principle of force transmission in a cylinder is as follows: F = P·S. Here, F represents the force, P represents the pressure (i.e., the pressure value of a single gas), and S represents the effective pressure-bearing area of ​​a single cylinder (i.e., the area of ​​the corresponding piston). From F = P·S, it can be seen that changing the area of ​​piston 503 can change the cylinder pressure.

[0067] like Figure 4As shown, piston 503 can convert air pressure into force, and transmit this force to base 1 through piston support column 504 and pressure plate 6. If the diameter of piston 503 is changed, its effective pressure-bearing area will also change, which will change the magnitude of the force exerted by pressure plate 6 on base 1 at that location, and the deformation of base 1 will also change accordingly. Figure 4 In the diagram, the pistons 503 of the drive components 5 at A1 and A2 have the same diameter, so the force transmitted to the corresponding pressure plates 6 is also the same. The pistons 503 of the drive components 5 at B1 and B2 have the same diameter, but are smaller than the pistons 503 of the drive components 5 at A1 and A2. Therefore, the force transmitted to the corresponding pressure plates 6 by the pistons 503 of the drive components 5 at B1 and B2 is relatively smaller. The piston 503 of the drive component 5 at C has the smallest diameter, and the force transmitted to the corresponding pressure plates 6 is also the smallest.

[0068] In this embodiment, since the bearing area of ​​the piston 503 is different in cylinders 502 of different diameters, the force acting on the base 1 is also different, making the deformation of the base 1 controllable.

[0069] In some specific examples, at least two drive components 5 are evenly distributed on the mounting plate 3.

[0070] It should be noted that, in addition to changing the effective pressure-bearing area of ​​the piston 503 in the above embodiments, the distribution position of the drive component 5 can also be adjusted to achieve zoned control of polishing pressure and rubber surface deformation under a single air pressure, thereby controlling the morphological flatness of the polished silicon wafer.

[0071] Furthermore, since the cylinder barrel 502 is detachable, the polishing pressure can also be controlled by removing the cylinder barrel 502.

[0072] like Figure 7 As shown, the drive components 5 are distributed relatively evenly. However, it is understandable that in actual production, the distribution can be adjusted according to actual needs (such as the target morphology of the incoming materials and silicon wafers). For example, at least two drive components 5 can be irregularly arranged on the mounting plate 3 as needed, instead of being evenly distributed.

[0073] In some embodiments, the vent cover 4 includes: a cover body 401, a connecting rod 402, and a limiting part 403; wherein, a first mounting hole is provided on the mounting plate 3, the connecting rod 402 passes through the first mounting hole, one end of the connecting rod 402 is connected to the cover body 401, and the other end is connected to the limiting part 403; the orthographic projection of the cover body 401 on the mounting plate 3 covers the upper opening of the vent 301; the outer diameter of the limiting part 403 is larger than the diameter of the first mounting hole.

[0074] In a specific example, the axis of the vent 301 is at a preset angle to the horizontal plane.

[0075] As an optional example, the preset angle can be in the range of [30°, 60°]. For example, the preset angle can be 30°, 45° or 50°.

[0076] like Figure 5 As shown, the mounting plate 3 is provided with an inclined vent hole 301, which makes it easier to install the vent hole cover 4 and ensures that when the cover body 401 in the vent hole cover 4 is sucked up and leaves the mounting plate 3, the limiting part 403 in the vent hole cover 4 will not block the lower opening of the vent hole 301.

[0077] In some embodiments, the weight of the vent cover 4 is less than a preset value.

[0078] It should be noted that the weight of the vent cover 4 is specifically related to the size of the vent 301 and the magnitude of the negative pressure introduced into the chamber by the polishing machine. Taking a vent 301 radius of 2mm and a negative pressure (P′) of 10-15kPa as an example, the weight of the vent cover 4 can satisfy: m≤P′·S′ / g. m represents the weight of the vent cover 4 (unit: kg), P′ represents the negative pressure (unit: Pascal), S′ represents the area of ​​the vent 301 (i.e., the pressure-bearing area of ​​the vent cover 4, unit: square meter), and g represents the acceleration due to gravity (unit: N / kg or m / s²).

[0079] As an optional example, the weight of the vent cover 4 can be in the range of (0, 18) grams. For example, the weight of the vent cover 4 can be 10 grams, 12 grams, or 15 grams.

[0080] The polishing head in this embodiment of the invention can be modified from a traditional single-pressure (single-chamber) polishing machine by adding a cylinder control layer (including mounting plate 3, drive assembly 5, pressure plate 6, etc.). In this way, by adjusting the effective pressure-bearing area and distribution points of the drive assembly in the polishing head, pressure distribution can be varied, thereby controlling the amount of material removed from different areas of the silicon wafer during the polishing process, achieving silicon wafer flatness control, and effectively improving the performance of the polishing machine.

[0081] This invention also provides a polishing apparatus, including the polishing head described above.

[0082] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, since the embodiments are basically similar to the product embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the product embodiments.

[0083] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0084] It is understandable that when a component such as a layer, film, region, or substrate is referred to as being "above" or "below" another component, the component may be "directly" located "above" or "below" the other component, or there may be intermediate components present.

[0085] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0086] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A polishing head, characterized in that, include: Base (1); A support part (2) is disposed on the first end face of the base (1), and there is a cavity between the support part (2) and the base (1). The cross-section of the support part (2) is annular. Mounting plate (3) is disposed in the cavity. Mounting plate (3) is fixedly connected to support part (2). Mounting plate (3) divides the cavity into a first cavity and a second cavity. The first cavity is located above the second cavity. Ventilation hole (301) is provided on mounting plate (3). Vent cover (4) is movably connected to the mounting plate (3), and the orthographic projection of the vent cover (4) on the mounting plate (3) covers the upper opening of the vent (301); At least two drive components (5) are mounted on the mounting plate (3); At least two pressure plates (6) are mounted on the drive assembly (5). The pressure plates (6) correspond one-to-one with the drive assembly (5). The drive assembly (5) is used to drive the pressure plates (6) to move in the vertical direction, which is perpendicular to the horizontal plane. The lower surface of the pressure plate (6) abuts against the base (1). The driving component (5) includes: Cylinder head (501), cylinder barrel (502), piston (503) and piston support column (504); The first end of the cylinder head (501) is mounted on the mounting plate (3); The cylinder barrel (502) is disposed in the second chamber and is fixedly connected to the second end of the cylinder head (501). The bottom of the cylinder barrel (502) is provided with a guide portion (5021) that penetrates the bottom surface of the cylinder barrel (502). There is an accommodating space between the cylinder head (501) and the cylinder barrel (502), the piston (503) is disposed in the accommodating space, and the edge of the piston (503) is in close contact with the inner wall of the cylinder barrel (502). The piston (503) divides the accommodating space into a first accommodating space and a second accommodating space. The first accommodating space is in communication with the first chamber. The first end of the piston support column (504) is fixedly connected to the piston (503), and the second end of the piston support column (504) passes through the guide part (5021) and extends out of the cylinder barrel (502), and is fixedly connected to the pressure plate (6).

2. The polishing head according to claim 1, characterized in that, The second end of the cylinder head (501) is provided with at least two first threaded holes of different diameters, and the cylinder barrel (502) is provided with threads that match the first threaded holes.

3. The polishing head according to claim 1, characterized in that, The vent cover (4) includes: Cover (401), connecting rod (402) and limiting part (403); The mounting plate (3) has a first mounting hole, and the connecting rod (402) passes through the first mounting hole. One end of the connecting rod (402) is connected to the cover (401), and the other end is connected to the limiting part (403). The orthographic projection of the cover (401) onto the mounting plate (3) covers the upper opening of the vent (301); The outer diameter of the limiting part (403) is larger than the diameter of the first mounting hole.

4. The polishing head according to claim 1 or 3, characterized in that, The axis of the vent (301) is at a preset angle to the horizontal plane.

5. The polishing head according to claim 1, characterized in that, The edge of the mounting plate (3) is inserted into the inner wall of the support part (2). The mounting plate (3) has a second threaded hole (302) and the support part (2) has a second mounting hole. The second mounting hole and the second threaded hole (302) are coaxially arranged. The fastening bolt (7) passes through the second mounting hole and is screwed into the second threaded hole (302).

6. The polishing head according to claim 1, characterized in that, A rubber ring (8) is provided between the mounting plate (3) and the support part (2).

7. The polishing head according to claim 1, characterized in that, The at least two drive components (5) are evenly distributed on the mounting plate (3).

8. The polishing head according to claim 1, characterized in that, The weight of the vent cover (4) is less than the preset value.

9. A polishing device, characterized in that, Includes the polishing head as described in any one of claims 1 to 8.

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