Polishing head and polishing equipment

Abstract

The invention provides a polishing head and polishing equipment, and belongs to the technical field of semiconductor manufacturing. Comprising a substrate (1); the supporting part (2) is arranged on the first end face of the base (1), and a cavity is formed between the supporting part (2) and the base (1); the mounting plate (3) is fixedly connected with the supporting part (2), the mounting plate (3) divides the cavity into a first cavity and a second cavity, and a vent hole (301) is formed in the mounting plate (3); the vent hole cover (4) is movably connected with the mounting plate (3), and the orthographic projection of the vent hole cover (4) on the mounting plate (3) covers the upper opening of the vent hole (301); the at least two driving assemblies (5) are mounted on the mounting plate (3); and the at least two pressure applying discs (6) are installed on the driving assembly (5), and the lower surfaces of the pressure applying discs (6) abut against the base (1). According to the technical scheme, the pressure distribution of the polishing head in different areas can be effectively improved, and the pressure requirement in the polishing process is met.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a polishing head and polishing equipment. Background Art

[0002] Under the requirement of shallow damage layer, the surface particle defects of large-sized silicon wafers such as 12 inches are usually removed by using an airbag polishing head. The positive and negative air pressure changes realize the whole process of grabbing, polishing and releasing the silicon wafer to complete the final single-side polishing (FP) processing.

[0003] Traditional single-chamber polishing heads utilize a rubber-base seal and a single air pressure piping system. These systems present two major technical bottlenecks: First, the polishing removal amount between the center and edge of the wafer varies significantly; second, the pressure cannot be dynamically adjusted based on the flatness and topography of the incoming material, making it difficult to control the polishing removal amount in each region of the wafer. While a multi-chamber design can improve pressure distribution, this requires costly modifications to the equipment's air pressure piping system. Summary of the Invention

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

[0005] In order to achieve the above objectives, the technical solution adopted in the embodiment of the present invention is:

[0006] A polishing head, comprising:

[0007] substrate;

[0008] A support portion is provided on the first end surface of the base, a cavity is defined between the support portion and the base, and the cross section of the support portion is annular;

[0009] A mounting plate is disposed in the chamber, the mounting plate is fixedly connected to the support portion, the mounting plate divides the chamber into a first chamber and a second chamber, the first chamber is located above the second chamber, and a vent hole is opened 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 assemblies mounted on the mounting plate;

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

[0013] In some embodiments, the drive assembly includes:

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

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

[0016] The cylinder barrel is arranged in the second chamber and is fixedly connected to the second end of the cylinder head. The bottom of the cylinder barrel is provided with a guide portion penetrating the bottom surface of the cylinder barrel;

[0017] There is a receiving space between the cylinder head and the cylinder barrel. The piston is arranged 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 portion 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 with different diameters, and the cylinder barrel is provided with threads matching the first threaded holes.

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

[0021] Cover body, connecting rod and limiting part;

[0022] The mounting plate is provided with a first mounting hole, the connecting rod is passed through the first mounting hole, one end of the connecting rod is connected to the cover body, and the other end is connected to the limiting portion;

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

[0024] The outer diameter of the limiting portion is greater than the diameter of the first mounting hole.

[0025] In some embodiments, the axis of the vent hole forms a predetermined angle with the horizontal plane.

[0026] In some embodiments, the edge of the mounting plate is inserted into the inner wall of the support portion, a second threaded hole is provided on the mounting plate, a second mounting hole is provided on the support portion, the second mounting hole is coaxially arranged with the second threaded hole, 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 portion.

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

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

[0030] An embodiment of the present invention further provides a polishing device, comprising the above polishing head.

[0031] The beneficial effects of the present invention are:

[0032] In this embodiment, at least two drive components and pressure plates are provided in the polishing head. Thus, the pressure distribution of each area on the polishing head can be controlled by adjusting the number and distribution position of the drive components and the force of the driving pressure plates, thereby controlling the removal amount of different areas on the silicon wafer during the polishing process and achieving flatness control of the silicon wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram showing the structure of a conventional single-pressure polishing head, adsorption pad, and silicon wafer;

[0034] Figure 2 Schematic diagram showing a conventional single-gas polishing head and adsorption pad grabbing a silicon wafer;

[0035] Figure 3 Schematic diagram showing the polishing / releasing of silicon wafers using a conventional single-gas pressure polishing head and adsorption pad;

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

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

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

[0039] Figure 7 A top view of a polishing head according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0041] Related technology introduction:

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

[0043] During the working process: 1) Grasping stage: Figure 2 As shown, by applying negative pressure to the chamber 04, the silicon wafer 05 is grasped by utilizing the synergistic effect of negative pressure adsorption and surface tension; 2) Polishing / unloading stage: Figure 3 As shown, positive pressure is applied to chamber 04. Due to the use of a single air pressure control, the air pressure distribution within chamber 04 is uniform, resulting in the same air pressure force applied to all parts of rubber base 02 (the pad is the polishing pad). However, due to the tension (reaction force) of support ring 01, the deformation at the edge of the rubber is significantly less than that in the center. This structural characteristic creates a difference in the net air pressure force at the center and edge, ultimately resulting in a non-uniform removal distribution from the center to the edge of silicon wafer 05. It is worth noting that differences in the initial morphology of silicon wafer 05 can further exacerbate this uneven removal, thereby affecting the controllability of the FP polishing process.

[0044] In order to solve the above technical problems, an embodiment of the present invention provides a polishing head and a polishing device, 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] A base 1 , a support portion 2 , a mounting plate 3 , a vent cover 4 , at least two drive assemblies 5 and at least two pressure plates 6 .

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

[0048] The support portion 2 is disposed on the first end surface of the base 1 , with a cavity defined between the support portion 2 and the base 1 . The cross section of the support portion 2 is annular.

[0049] The mounting plate 3 is arranged in the chamber and is fixedly connected to the support part 2. The mounting plate 3 divides the chamber into a first chamber and a second chamber. The first chamber is located above the second chamber. A vent hole 301 is opened on the 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, a second threaded hole 302 is opened on the mounting plate 3, and a second mounting hole is opened on the support part 2. The second mounting hole is coaxially arranged with the second threaded hole 302, and 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 supporting portion 2 .

[0052] Here, in order to ensure airtightness, a rubber ring 8 may be provided at the connection between the support portion 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 assemblies 5 are mounted on the mounting plate 3 .

[0055] At least two pressure plates 6 are mounted on the driving assembly 5 , and the pressure plates 6 correspond to the driving assembly 5 one by one. The driving 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 plates 6 abuts against the base 1 .

[0056] In some specific examples, the areas of the pressure plates 6 are the same.

[0057] Here, the working principle of the polishing head according to the embodiment of the present invention is described as follows:

[0058] like Figure 5 As shown, when the polishing head needs to grab a silicon wafer, the polishing machine introduces negative pressure into the chamber, which lifts the lightweight vent cover 4 and opens the vent hole 301 on the mounting plate 3, connecting the first and second chambers. Substrate 1 then concaves under the negative pressure. At this point, pressure plate 6 remains in contact with substrate 1 due to gravity, and its large area acts as a retaining force on substrate 1, preventing excessive deformation of substrate 1 under the negative pressure, which could lead to breakage and failure.

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

[0060] In this embodiment, at least two drive components and pressure plates are provided in the polishing head. Thus, the pressure distribution of each area on the polishing head can be controlled by adjusting the distribution of the drive components and the force of the driving pressure plate, thereby controlling the removal amount of different areas on the silicon wafer during the polishing process and achieving flatness control of the silicon wafer.

[0061] like Figure 4As shown, in some embodiments, the driving 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 arranged in the second chamber and is 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 that passes through the bottom surface of the cylinder barrel 502; there is a accommodating space between the cylinder head 501 and the cylinder barrel 502, and the piston 503 is arranged in the accommodating space, and the edge of the piston 503 is tightly attached to the inner wall of the cylinder barrel 502, and the piston 503 divides the accommodating space into a first accommodating space and a second accommodating space, and the first accommodating space is connected to 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 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 opened in the center of the first end of the cylinder head 501 , so that the first accommodating space can be connected to the first chamber, so that 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 pressurize polishing or release the silicon wafer, the polishing machine introduces positive pressure into the chamber, and the vent 301 on the mounting plate 3 is sealed by the vent cover 4, and the first accommodating space is connected to the first chamber. Therefore, the piston 503 in the driving assembly 5 moves back and down under the action of air pressure, thereby converting the air pressure into a force, and through the conduction action of the piston support column 504 and the pressure plate 14 on the substrate 1, the substrate 1 is supported, thereby achieving regional precise control of the polishing force, and thus obtaining a silicon wafer with a target flatness morphology.

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

[0065] That is, in the embodiment of the present invention, each cylinder head 501 can be provided with multiple threaded connection ports (first threaded holes) of different diameters for adapting to cylinder barrels 502 of different sizes (diameters). The cylinder barrels 502 are screwed into the first threaded holes on the cylinder head 501 by threads.

[0066] It should be noted that the basic principle of force transmission by a cylinder is as follows: F = P·S. Here, F represents the force, P represents the pressure (i.e., the pressure 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 converts air pressure into force, which is then transferred to substrate 1 via piston support column 504 and pressure plate 6. Changing the diameter of piston 503 changes its effective pressure-bearing area, which in turn changes the force exerted by pressure plate 6 on substrate 1 at that location, thereby changing the deformation of substrate 1. Figure 4 In the figure, the pistons 503 of the drive assemblies 5 at A1 and A2 have the same diameter, so the forces transmitted to the corresponding pressure plates 6 are also the same. The pistons 503 of the drive assemblies 5 at B1 and B2 have the same diameter, but are smaller in diameter than the pistons 503 of the drive assemblies 5 at A1 and A2. Therefore, the forces transmitted to the corresponding pressure plates 6 by the pistons 503 of the drive assemblies 5 at B1 and B2 are also relatively smaller. The piston 503 of the drive assembly 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 pressure-bearing areas of the piston 503 are different in the cylinders 502 with different diameters, the forces acting on the substrate 1 are also different, so that the deformation of the substrate 1 is controllable.

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

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

[0071] In addition, since the cylinder barrel 502 is detachable, the polishing pressure can be regulated in different zones by disassembling the cylinder barrel 502 .

[0072] like Figure 7 As shown, the drive assemblies 5 are relatively evenly distributed. However, it is understood that in actual production, zoning control can be performed based on actual needs (such as the target morphology of the incoming material and the silicon wafer). For example, at least two drive assemblies 5 can be irregularly arranged on the mounting plate 3 as needed, rather than being evenly distributed.

[0073] In some embodiments, the vent cover 4 includes: a cover body 401, a connecting rod 402 and a limiting portion 403; wherein, a first mounting hole is opened on the mounting plate 3, the connecting rod 402 is passed 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 portion 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 portion 403 is larger than the diameter of the first mounting hole.

[0074] In a specific example, the axis of the vent hole 301 forms a preset angle with the horizontal plane.

[0075] As an optional example, the value range of the preset angle is [30°, 60°]. For example, the preset angle may specifically be: 30°, 45° or 50°.

[0076] like Figure 5 As shown, an inclined vent hole 301 is provided on the mounting plate 3, which makes it easier to install the vent cover 4 and ensures that when the cover body 401 in the vent cover 4 is sucked up and leaves the mounting plate 3, the limiting portion 403 in the vent 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 hole 301 and the negative pressure introduced into the chamber by the polishing machine. Taking the radius of the vent hole 301 as 2 mm and the negative pressure (P') as 10-15 kPa, the weight of the vent cover 4 can satisfy the following conditions: m ≤ P'·S' / g. m represents the weight of the vent cover 4 (unit: kilograms), P' represents the pressure of the negative pressure (unit: Pascals), S' represents the area of ​​the vent hole 301 (i.e., the pressure-bearing area of ​​the vent cover 4, unit: square meters), and g represents the acceleration due to gravity (unit: Newtons / kilogram or meters / second²).

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

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

[0081] An embodiment of the present invention further provides a polishing device, comprising the above polishing head.

[0082] It should be noted that the various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences from other embodiments. In particular, since the embodiments are generally similar to the product embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the product embodiments.

[0083] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0084] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “under” another element, it can be “directly on” or “under” the other element or intervening elements may be present.

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

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

Claims

1. A polishing head, characterized in that: include: substrate (1); A support portion (2) is arranged on the first end surface of the base (1), a chamber is defined between the support portion (2) and the base (1), and the cross section of the support portion (2) is annular; a mounting plate (3) disposed in the chamber, the mounting plate (3) being fixedly connected to the support portion (2), the mounting plate (3) dividing the chamber into a first chamber and a second chamber, the first chamber being located above the second chamber, and a vent hole (301) being provided on the mounting plate (3); A 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 assemblies (5) mounted on the mounting plate (3); At least two pressure plates (6), the pressure plates (6) are mounted on the driving assembly (5), the pressure plates (6) correspond to the driving assembly (5) one by one, the driving assembly (5) is used to drive the pressure plates (6) to move in a vertical direction, the vertical direction is perpendicular to the horizontal plane, and the lower surface of the pressure plates (6) abuts against the base (1).

2. The polishing head according to claim 1, characterized in that The driving assembly (5) comprises: Cylinder head (501), cylinder barrel (502), piston (503) and 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); a guide portion (5021) penetrating the bottom surface of the cylinder barrel (502) is disposed at the bottom of the cylinder barrel (502); There is an accommodating space between the cylinder head (501) and the cylinder barrel (502), the piston (503) is arranged in the accommodating space, and the edge of the piston (503) is in close contact with the inner wall of the cylinder barrel (502), and the piston (503) divides the accommodating space into a first accommodating space and a second accommodating space, and the first accommodating space is communicated 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 portion (5021) and extends outside the cylinder barrel (502), and is fixedly connected to the pressure plate (6).

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

4. The polishing head according to claim 1, characterized in that The vent cover (4) comprises: A cover body (401), a connecting rod (402) and a limiting portion (403); The mounting plate (3) is provided with a first mounting hole, the connecting rod (402) is passed 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 portion (403); The orthographic projection of the cover (401) on the mounting plate (3) covers the upper opening of the vent hole (301); The outer diameter of the limiting portion (403) is greater than the diameter of the first mounting hole.

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

6. 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 portion (2); a second threaded hole (302) is provided on the mounting plate (3); a second mounting hole is provided on the support portion (2); the second mounting hole and the second threaded hole (302) are coaxially arranged; a fastening bolt (7) passes through the second mounting hole and is screwed into the second threaded hole (302).

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

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

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

10. A polishing device, characterized in that: The polishing head comprises the polishing head according to any one of claims 1 to 9.

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