Bearing head and polishing device for electrochemical mechanical polishing

Abstract

The invention discloses a bearing head and a polishing device for electrochemical mechanical polishing, and belongs to the technical field of semiconductor manufacturing. The bearing head for electrochemical mechanical polishing comprises a bearing head body, an elastic film and a retaining ring are arranged below the bearing head body, the retaining ring is arranged on the peripheral side of the elastic film, and an electric conductor is arranged below the retaining ring; and the elastic film is a conductive gas film and is communicated with the electric conductor and an electrode of a power supply part required by electrochemical mechanical polishing, so that a conductive loop is formed by the elastic film and the polishing solution, and a wafer to be polished is positioned in the conductive loop.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and more particularly to a support head and polishing apparatus for electrochemical mechanical polishing. Background Technology

[0002] In semiconductor processing technology, compared to traditional chemical mechanical polishing (CMP), electrochemical mechanical polishing (ECMP) offers a higher material removal rate (MRR) for SiC wafer polishing. ECMP primarily utilizes electrochemical modification to generate an oxide layer on the SiC surface with a hardness lower than the SiC substrate, which is then removed mechanically. To achieve the electrochemical effect on the wafer, current technologies employ drilling holes in the polishing pad, with an electrolytic polishing solution within the holes providing conductivity. A conductive path is formed by the polishing head, wafer, via electrolyte, and polishing stage, thereby achieving oxidation of the silicon carbide wafer surface under electrochemical action.

[0003] Current ECMP technology, which applies electrochemical processes to silicon carbide wafers, uses a polishing pad drilling method. This method has the following drawbacks:

[0004] (1) Current passes through the polishing pad, which needs to be insulated from other metal parts. However, the connection and fixing points between the polishing pad and other metal parts cannot guarantee insulation, which poses a safety hazard to the equipment. Specifically, during high-speed rotation and long-term use, the insulation layer is prone to wear or aging, which increases the risk of short circuits and may cause equipment failure or wafer damage.

[0005] (2) After the polishing pad is perforated, the perforated area cannot participate in mechanical grinding normally, which affects the material removal rate and the service life of the polishing pad. In addition, perforation will cause the polishing pad surface to be uneven, resulting in uneven polishing, wafer surface defects, and reduced product yield. Summary of the Invention

[0006] In view of this, embodiments of this application provide a bearing head and polishing apparatus for electrochemical mechanical polishing. By directly integrating the conductor into the retaining ring of the bearing head, a conductive circuit is formed in conjunction with the elastic membrane, avoiding the need for drilling holes in the polishing pad. This fundamentally eliminates insulation safety hazards and improves polishing uniformity and efficiency. Furthermore, this invention enhances wear resistance and conductive stability by optimizing the structure and material of the conductor, thereby at least partially solving the aforementioned problems.

[0007] According to a first aspect of the present application, a support head for electrochemical mechanical polishing is provided, comprising a support head body, an elastic membrane and a retaining ring disposed below the support head body, the retaining ring being disposed on the outer periphery of the elastic membrane, and a conductor being disposed below the retaining ring; the elastic membrane is a conductive gas membrane, and the elastic membrane and the conductor are connected to the electrodes of the power supply section required for electrochemical mechanical polishing to form a conductive circuit with the polishing liquid, so that the wafer to be polished is placed in the conductive circuit.

[0008] In some embodiments, a pair of conductive terminals are disposed on the top of the bearing head body, which are respectively connected to the elastic membrane and the conductor; the conductive terminals disposed on the elastic membrane are connected to the center of the inner side of the elastic membrane.

[0009] In some embodiments, the retaining ring includes a retaining ring body with an annular mounting groove on its bottom surface, and the conductor is a ring structure concentrically disposed in the mounting groove.

[0010] In some embodiments, the conductor is made of a wear-resistant substrate that is internally doped to become conductive; the retaining ring body is made of the same material as the substrate of the conductor, which is made of polyphenylene sulfide, polyether ether ketone, reinforced polyethylene terephthalate, or polyamide-imide.

[0011] In some embodiments, the doping treatment includes incorporating a conductive filler, the conductive filler comprising a composite carbon material of carbon nanotubes and graphene, wherein the mass fraction of carbon nanotubes is 1%-5% of the substrate and the mass fraction of graphene is 0.5%-2% of the substrate.

[0012] In some embodiments, the mass ratio of carbon nanotubes to graphene is controlled within the range of 2:1 to 5:1 to form a stable three-dimensional conductive network in the conductor, ensuring stable conductivity even under friction and wear conditions.

[0013] In some embodiments, the conductor is a rod-shaped structure, which is vertically disposed in a placement groove that runs through the inside of the retaining ring; a first spring is disposed on the outer periphery of the conductor to press the conductor downward so that its lower end passes through the lower port of the placement groove.

[0014] In some embodiments, the number of conductors is multiple, which are spaced apart circumferentially along the holding ring; the multiple conductors are distributed at equal intervals, so that the current formed by the conductive circuit is uniformly distributed at the edge of the wafer.

[0015] In some embodiments, the bottom surface of the retaining ring is provided with a liquid infusion tank for conveying polishing slurry for electrochemical mechanical polishing; the placement tank and the liquid infusion tank are staggered to prevent the installed conductor from affecting the supply of polishing slurry.

[0016] According to a second aspect of the embodiments of this application, an electrochemical mechanical polishing apparatus is provided, comprising:

[0017] A polishing disc with a polishing pad on its top surface;

[0018] The aforementioned carrier head is used to load the wafer to be processed;

[0019] The liquid supply section is used to supply polishing liquid toward the polishing pad;

[0020] The power supply unit is electrically connected to the carrier head via an adapter assembly, so that the wafer is placed in the conductive circuit formed by the elastic membrane, retaining ring and polishing fluid of the carrier head.

[0021] In some embodiments, the adapter assembly is disposed at the lower part of the polishing shaft and includes a pair of vertically arranged conductive elements; the conductive elements are connected to conductive terminals at the top of the carrier head to conduct the conductive circuit.

[0022] In some embodiments, the adapter assembly further includes an elastic loading structure disposed above the conductive element to drive the conductive element to move in the vertical direction, thereby compensating for the positional deviation between the bearing head and the adapter assembly, so that the conductive element always abuts against the surface of the conductive terminal.

[0023] In some embodiments, the elastic loading structure includes a protective sleeve and a second spring, the second spring being sleeved on the outer periphery of the conductive element, and the assembly formed by the second spring and the conductive element being disposed in the protective sleeve.

[0024] In some embodiments, the lower end of the second spring abuts against the locking platform of the conductive element, and its upper end abuts against the top wall of the protective sleeve.

[0025] In some embodiments, the protective sleeve is a cylindrical structure with a hole at one end, and a limiting platform is disposed on its inner side. The setting size of the limiting platform matches the setting size of the locking platform.

[0026] The beneficial effects of this invention include:

[0027] a. This invention integrates a conductor into the bearing head retaining ring, forming a conductive circuit in conjunction with a conductive elastic membrane, thus eliminating the need for drilling holes in the polishing pad in existing technologies. This eliminates the need for current to pass through the polishing pad and its connection points, thereby completely avoiding the risk of short circuits caused by insulation wear or aging, and significantly improving the safety and long-term reliability of the equipment;

[0028] b. Since there is no need to drill holes in the polishing pad, the integrity and flatness of the polishing pad surface are maintained, ensuring the uniformity of the mechanical polishing action. At the same time, through the design of the annular or multi-point evenly distributed conductor, the current is evenly distributed at the edge of the wafer. Combined with the complete polishing surface of the polishing pad, this improves the polishing uniformity and material removal rate, and effectively extends the service life of the polishing pad.

[0029] c. This invention employs a polymer-based conductor doped with composite carbon materials, forming a stable three-dimensional conductive network through a specific formulation and dispersion process. This design ensures excellent wear resistance while avoiding the introduction of metal ions, thus fundamentally preventing wafer contamination. Combined with an elastic loading structure, it ensures the continuous stability of electrical connections during dynamic polishing, comprehensively guaranteeing high-quality polishing results. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0031] Figure 1 This is a schematic diagram of a bearing head provided in an embodiment of the present invention;

[0032] Figure 2 This is a cross-sectional view of a retaining ring provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of a bearing head provided in another embodiment of the present invention;

[0034] Figure 4 yes Figure 3 A magnified view of a section at point A in the middle;

[0035] Figure 5 This is a schematic diagram of an electrochemical mechanical polishing apparatus provided in an embodiment of the present invention;

[0036] Figure 6 yes Figure 5 A magnified view of a section at point B in the middle;

[0037] Figure 7 This is a schematic diagram of an elastic loading structure provided in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of a protective sleeve provided in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of a conductor provided in an embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0041] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0042] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0043] Figure 1 This is a schematic diagram of a carrier head 100 provided in an embodiment of the present invention, which is used for electrochemical mechanical polishing of wafers.

[0044] The support head 100 includes a support head body 10. An elastic membrane 20 and a retaining ring 30 are disposed below the support head body 10, wherein the retaining ring 30 is located on the outer periphery of the elastic membrane 20. The retaining ring 30 is mainly used to define the position of the polished wafer and prevent it from sliding out of the support head 100 under lateral force. A liquid infusion groove 34 is provided at the bottom end of the retaining ring 30. Figure 2 (As shown), to deliver polishing slurry between the polishing pad and the wafer; in addition, the retaining ring 30 can also participate in the regulation of polishing pressure, that is, to improve the non-uniformity of wafer removal rate by adjusting the pressure of the retaining ring 30.

[0045] Unlike existing technologies, the carrier head 100 of the present invention integrates electrochemical functions. Figure 1In the illustrated embodiment, a conductor 31 is disposed below the retaining ring 30 and is connected to the cathode of the power supply unit 200. The elastic film 20 is a conductive gas film and is connected to the anode of the power supply unit 200; the elastic film 20, the conductor 31, and the polishing liquid form a conductive circuit, so that the wafer to be polished is placed in the conductive circuit.

[0046] This design fundamentally eliminates the traditional method of conducting electricity by drilling holes in the polishing pad, allowing the current loop to completely bypass the polishing disc 300 ( Figure 5 As shown in the diagram, its complex mechanical connection structure eliminates the risk of short circuits caused by insulation wear or aging at the source, greatly improving the safety and reliability of the equipment and the process. Compared with the prior art, this invention simplifies the electrochemical circuit by integrating conductive devices into the bearing head 100, avoiding the mechanical performance degradation and insulation problems caused by drilling holes in the polishing pad.

[0047] Furthermore, a pair of conductive terminals 40 are disposed on the top of the carrier head body 10, which are respectively connected to the elastic film 20 and the conductor 31; wherein, the conductive terminals 40 disposed on the elastic film 20 are connected to the center position inside the elastic film 20, so that the wafer loaded on the elastic film 20 is located at the center of the conductive circuit of electrochemical mechanical polishing. This centrally symmetrical electrical connection design helps to form a more uniform electric field distribution on the wafer surface, laying the foundation for the subsequent realization of a uniform electrochemical modification layer.

[0048] In this invention, the retaining ring 30 includes a retaining ring body 32, such as... Figure 1 and Figure 2 As shown, the bottom surface of the device is provided with an annular mounting groove 33, and the conductor 31 has an annular structure, which is concentrically arranged in the mounting groove 33. That is, the bottom surface of the conductor 31 is flush with the bottom surface of the retaining ring body 32, so that the conductor 31 can fully contact the polishing liquid above the polishing pad. The design of the annular conductor 31 can ensure the formation of a continuous and uniform annular electrical contact with the edge area of ​​the wafer, effectively avoiding the problem of excessively high or low local current density that may be caused by point contact, thereby significantly improving the polishing uniformity.

[0049] Understandably, the bottom surface of the conductor 31 is fitted with grooves to ensure the normal transmission of polishing fluid. Specifically, during the fabrication of the retaining ring 30, the conductor 31 can be fixed in the mounting groove 33, making the two an integral structure, and then the fluid delivery groove 34 is machined at the bottom of the integral structure. This integrated manufacturing method ensures the integrity of the fluid delivery groove 34, preventing interruption due to the presence of the conductor 31, thereby ensuring a smooth and uniform supply of polishing fluid.

[0050] In this invention, the conductor 31 is made of a wear-resistant substrate, which is internally doped to achieve conductivity. Furthermore, the retaining ring body 32 is made of the same material as the substrate of the conductor 31 to ensure that both have the same wear resistance. This material consistency design ensures that the conductor 31 and the retaining ring body 32 have similar wear rates in the working environment, effectively avoiding "virtual connection" situations such as interruption of the conductive circuit or poor contact due to premature wear of the conductor 31, and ensuring the continuous stability of the electrochemical polishing process.

[0051] Furthermore, the retaining ring body 32 is made of polyphenylene sulfide (PPS), polyether ether ketone (PEEK), reinforced polyethylene terephthalate (PET-P), or polyamide-imide (PAI) to ensure the wear resistance of the retaining ring 30. Simultaneously, the high mechanical strength and strong insulation properties of these materials, along with their resistance to high temperatures, impact, flame retardancy, acids and alkalis, hydrolysis, and fatigue, make them suitable for the electrochemical mechanical polishing (EMF) environment of wafers.

[0052] In this invention, the conductor 31 requires doping treatment of the substrate, that is, incorporating conductive filler into the substrate. The conductive filler comprises a composite carbon material of carbon nanotubes and graphene, wherein the mass fraction of carbon nanotubes is 1%-5% of the substrate, and the mass fraction of graphene is 0.5%-2% of the substrate.

[0053] The doping process is key to achieving high-performance conductors in this invention. Specifically, one-dimensional carbon nanotubes and two-dimensional graphene interlock within the matrix, forming a more complete and stable three-dimensional conductive network. This synergistic effect allows conductor 31 to achieve excellent conductivity with relatively low filler content, which helps to maximize the preservation of conductor 31's inherent excellent wear resistance and mechanical strength while imparting conductivity to the matrix. By optimizing the filler ratio, this invention solves the problems of easy wear and wafer contamination caused by traditional metal fillers, providing a more stable and cleaner conductive solution.

[0054] In this invention, precise control of the filler ratio is required to optimize performance. Specifically, the mass ratio of carbon nanotubes to graphene is controlled within the range of 2:1 to 5:1. This ratio is based on an optimized range verified by numerous experiments. Within this optimized range, one-dimensional carbon nanotubes can effectively bridge the gaps between two-dimensional graphene sheets, forming a stable three-dimensional conductive network that is interwoven and complementary. Even under high-intensity friction and wear conditions, this network structure can maintain the integrity of the conductive pathways through dynamic reconstruction, thereby significantly improving the conductivity stability of the conductor during long-term use, and its volume resistivity can be stabilized at 10 Ω·cm. 2 The value is on the order of Ω·cm. This optimized selection of the content and proportion of key components can significantly improve the conductivity stability of conductors under long-term frictional use.

[0055] It should be noted that this invention uses carbon-based materials such as carbon nanotubes and graphene to replace traditional metal-based conductive fillers (such as silver powder and copper powder), thus eliminating the risk of metal ion dissolution and wafer contamination due to friction and wear at the material source. This is crucial for the electrochemical mechanical polishing (ECMP) process in semiconductor manufacturing, which has extremely high cleanliness requirements, and is the core guarantee for achieving high-yield, contamination-free polishing. Experimental data shows that using... Figure 1 The polishing head 100 shown showed no metal ion contamination on the wafer surface after 100 hours of continuous operation, while the conventional metal filler control group showed obvious copper ion residue.

[0056] Meanwhile, carbon nanotubes and graphene themselves also have excellent wear resistance properties. By combining conductive fillers with specific wear-resistant substrates (such as PPS, PEEK, etc.) and optimizing their dispersion process, it is possible to give the matrix good conductivity while ensuring that the conductor 31 meets the wear resistance requirements during the polishing process, thereby extending the service life of the bearing head 100.

[0057] The following is a brief description Figure 1 The method for preparing the conductor 31 shown is as follows:

[0058] Pretreatment of conductive fillers: Acidification or surface treatment of carbon nanotubes and graphene to improve their dispersibility and interfacial bonding in the polymer matrix.

[0059] Specifically, surface grafting treatments are performed on carbon nanotubes and graphene. For example, atom transfer radical polymerization (ATRP) is used to graft polymer chains compatible with the substrate (such as PPS) onto the filler surface. The grafted polymer chains are physically entangled with the molecular chains of the PPS / PEEK substrate, resulting in good compatibility. This allows carbon nanotubes / graphene to be uniformly dispersed in the polymer matrix, laying the foundation for the formation of a uniform and stable three-dimensional conductive network. More importantly, this strong interfacial bonding effectively transfers frictional stress from the relatively fragile matrix-filler interface to the high-strength filler itself, greatly reducing filler shedding during friction. This is crucial for achieving stable conductivity and avoiding particulate contamination.

[0060] Multi-stage blending and dispersion: High-speed stirring and ultrasonic oscillation are combined to ensure that the conductive filler is uniformly dispersed in the matrix material, avoiding uneven local conductivity or decreased mechanical properties due to agglomeration.

[0061] Specifically, high-speed stirring generates powerful shear forces and turbulence in the mixing system. This powerful fluid force effectively breaks down and disperses the large macroscopic agglomerates of conductive fillers (carbon nanotubes / graphene) formed by van der Waals forces, initially breaking them into smaller particles and allowing them to mix with the polymer substrate or solvent. The subsequent ultrasonic dispersion utilizes its cavitation effect to generate instantaneous extreme high temperature and pressure, precisely overcoming the van der Waals forces between the microscopic agglomerates of the filler, achieving nanoscale fine dispersion. This synergistic dispersion process combining "macroscopic shearing" and "microscopic cavitation" is an indispensable step in constructing high-performance composite conductors.

[0062] Molding and processing: Conductor 31 is processed by injection molding process. This process is suitable for large-scale production and can ensure the uniformity and stability of the composite material properties.

[0063] In some embodiments, the conductor 31 is made of polyphenylene sulfide (PPS) substrate doped with carbon nanotubes and graphene, wherein the mass fraction of carbon nanotubes is 3% and the mass fraction of graphene is 1%, with a mass ratio controlled at 3:1. Through surface treatment with atom transfer radical polymerization (ATRP), the filler dispersion uniformity reaches over 95%, and the volume resistivity is stabilized at 10 Ω·cm. 2 The conductivity at Ω·cm showed a decrease of <10% after a wear test (100 hours), significantly better than the metal filler control group (decay >50%). More importantly, trace element analysis of the polished SiC wafer surface revealed no contamination from transition metal ions such as Fe, Cu, and Al introduced by the conductor. This parameter optimization ensures the stability of the three-dimensional conductive network under frictional conditions, avoiding the ion contamination risk associated with traditional metal fillers.

[0064] Figure 3 This is a schematic diagram of a carrier head 100 provided in another embodiment of the present invention. In this embodiment, the conductor 31 is a rod-shaped structure, which is vertically disposed in a placement groove 35 that passes through the inside of the retaining ring 30, such as... Figure 4 As shown.

[0065] Furthermore, there are multiple placement slots 35, which are evenly distributed along the circumference of the holding ring 30; and the placement slots 35 are located at the center of the radial direction of the holding ring 30. Correspondingly, there are multiple conductors 31, which are spaced along the circumference of the holding ring 30; the multiple conductors 31 are distributed at equal intervals. This multi-point uniform contact design can form a ring of discrete but uniformly distributed current injection points at the edge of the wafer. Compared with the scheme of annular conductors 31, it further reduces the occupation of the bottom structure of the holding ring 30 while ensuring the uniformity of current distribution.

[0066] Furthermore, a first spring 36 is disposed on the outer periphery of the conductor 31 to press the conductor 31 downward, so that its lower end passes through Figure 4 The lower port of the placement groove 35 is shown, allowing the conductor 31 to abut against the surface of the polishing pad. Specifically, the placement groove 35 is a stepped hole, and the conductor 31 is a stepped shaft. The shoulder of the conductor 31 abuts against the stepped hole of the placement groove 35, and one end of the first spring 36 abuts against the shoulder, while the other end abuts against a groove on the lower surface of the support head body 10. The rod-shaped conductor 31, under the compression of the first spring 36, has its lower end face abut against the surface of the polishing pad. This elastic support structure ensures that the conductor 31 and the polishing pad / wafer maintain a tight physical contact at all times, effectively compensating for gap changes caused by unevenness of the polishing pad surface or equipment vibration, thereby ensuring the continuous stability of the electrical connection during dynamic polishing and avoiding the adverse effects of current discontinuity on polishing quality.

[0067] In this invention, the elastic coefficient of the first spring 36 is 5-10 N / mm, ensuring that the contact force between the lower end of the conductor 31 and the polishing pad remains within the range of 0.5-1.5 N. Tests show that under polishing vibration conditions (frequency 5-20 Hz), this design results in electrical connection resistance fluctuations of <5%, while rigid designs exhibit fluctuations of >30%, significantly improving electrical connection stability.

[0068] Furthermore, the placement tank 35 and the infusion tank 34 are staggered to prevent the installed conductor 31 from affecting the supply of polishing fluid. That is, the conductor 31 is avoided from being placed in the infusion tank 34, preventing it from obstructing the normal delivery of the polishing fluid. This staggered layout design of the "conductivity-flow" path achieves perfect decoupling and integration of functions within a limited space, ensuring both the reliability of the electrical connection and the sufficiency and uniformity of the polishing fluid supply, working together to improve polishing efficiency and surface quality.

[0069] Meanwhile, the present invention also provides an electrochemical mechanical polishing device 1000, the schematic diagram of which is shown below. Figure 5 As shown, the electrochemical mechanical polishing apparatus 1000 includes:

[0070] Polishing disc 300, with a polishing pad on its top surface;

[0071] Figure 1 or Figure 3 The carrier head 100 shown is used to load the wafer to be processed;

[0072] The liquid supply unit 400 is used to supply polishing liquid toward the polishing pad;

[0073] Power supply unit 200, which passes through Figure 6 The adapter assembly 50 shown is electrically connected to the carrier head 100, such that the wafer is in a conductive circuit formed by the elastic membrane 20, the retaining ring 30, and the polishing slurry of the carrier head 100.

[0074] Figure 6 yes Figure 5 The enlarged view at point B shows that the adapter component 50 is located at the lower part of the polishing shaft 110. The adapter component 50 includes a pair of conductive elements 51, which are vertically spaced apart so that they are not connected to each other.

[0075] Furthermore, the conductive element 51 is connected to the conductive terminal 40 at the top of the bearing head 100, thereby connecting the conductive circuit formed by the elastic membrane 20, the retaining ring 30, and the polishing liquid of the bearing head 100.

[0076] In this invention, the adapter assembly 50 further includes an elastic loading structure 53, which is disposed above the conductive element 51 to drive the conductive element 51 to move appropriately in the vertical direction, thereby compensating for the positional deviation between the bearing head 100 and the adapter assembly 50. This ensures that the conductive element 51 always abuts against the surface of the conductive terminal 40, thus maintaining a continuous electrical connection during dynamic polishing and preventing incomplete connections in the adapter assembly 50 that could affect the stability of the electrochemical mechanical polishing. It should be noted that... Figure 6 In the diagram, double-dotted lines are used to represent connecting wires, one end of which is connected to conductive component 51 and conductive terminal 40. This design ensures that the electrical connection points maintain low resistance and continuous physical contact throughout the entire polishing process, from static contact to high-speed rotation, which is an important guarantee for achieving a stable and controllable electrochemical polishing process.

[0077] Furthermore, the adapter component 50 includes an adapter body 52, such as Figure 6 As shown, the adapter body 52 is provided with a vertical through hole, and the conductive element 51 is disposed in the through hole.

[0078] Figure 7 This is a schematic diagram of an elastic loading structure 53 provided in an embodiment of the present invention. In this embodiment, the elastic loading structure 53 includes a protective sleeve 531 and a second spring 532. The second spring 532 is sleeved on the outer periphery of the conductive member 51, and the component formed by the second spring 532 and the conductive member 51 is disposed in the protective sleeve 531.

[0079] Protective sleeve 531 is a cylindrical structure with an opening at one end, such as... Figure 8 As shown, a limiting stage 5311 is arranged on its inner side, and the setting size of the limiting stage 5311 is the same as that of the locking stage 511 on the conductive component 51. Figure 9 The dimensions are matched to prevent the conductive element 51 from slipping out of the protective sleeve 531, while limiting the downward movement distance of the conductive element 51 to prevent the vertical movement of the conductive element 51 from exceeding the limit.

[0080] Meanwhile, the lower end of the second spring 532 abuts against the locking platform 511, and its upper end abuts against the top wall of the protective sleeve 531, so that the second spring 532 is in a compressed state.

[0081] In this invention, the elastic force of the second spring 532 along the length of the protective sleeve 531 can bring the lower end face of the conductive element 51 against the conductive terminal 40 of the bearing head 100 to maintain the electrical connection between the two and prevent external factors such as vibration during the polishing process from affecting the polishing stability.

[0082] In this invention, the elastic coefficient of the second spring 532 is 8-12 N / mm, so that the conductive component 51 always abuts against the conductive terminal 40 with a force of 1-2 N, ensuring that the electrical connection is uninterrupted under high-speed rotation.

[0083] The elastic design of the adapter component 50 of this invention, in conjunction with the elastic conductor 31 inside the carrier head 100, constructs a dual elastic protection system, ensuring the reliability of the electrical connection under high-speed rotation and vibration environments. Tests show that at the highest rotational speed of the carrier head 100, the contact resistance of the electrical connection point remains stable, with no momentary disconnection.

[0084] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application. The above embodiments are only used to illustrate the embodiments of this application and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A support head for electrochemical mechanical polishing, characterized in that, The device includes a support head body, with an elastic membrane and a retaining ring disposed below it. The retaining ring is located on the outer periphery of the elastic membrane, and a conductor is disposed below the retaining ring. The elastic membrane is a conductive gas membrane, and it and the conductor are connected to the electrodes of the power supply unit required for electrochemical mechanical polishing to form a conductive circuit with the polishing liquid, so that the wafer to be polished is placed in the conductive circuit.

2. The bearing head according to claim 1, characterized in that, The top of the bearing head body is provided with a pair of conductive terminals, which are respectively connected to the elastic membrane and the conductor; the conductive terminals of the elastic membrane are connected to the center of the inner side of the elastic membrane.

3. The bearing head according to claim 1, characterized in that, The retaining ring includes a retaining ring body with an annular mounting groove on its bottom surface, and the conductor is a ring structure concentrically arranged in the mounting groove.

4. The bearing head according to claim 3, characterized in that, The conductor is made of a wear-resistant substrate and is internally doped to become conductive; the retaining ring body is made of the same material as the substrate of the conductor, which is made of polyphenylene sulfide, polyether ether ketone, reinforced polyethylene terephthalate or polyamide-imide.

5. The bearing head according to claim 4, characterized in that, The doping treatment includes incorporating conductive fillers, which include composite carbon materials of carbon nanotubes and graphene, wherein the mass fraction of carbon nanotubes is 1%-5% of the substrate and the mass fraction of graphene is 0.5%-2% of the substrate.

6. The bearing head according to claim 5, characterized in that, The mass ratio of carbon nanotubes to graphene is controlled within the range of 2:1 to 5:1 to form a stable three-dimensional conductive network in the conductor, ensuring stable conductivity even under friction and wear conditions.

7. The bearing head according to claim 1, characterized in that, The conductor is a rod-shaped structure, which is vertically arranged in a through placement groove inside the retaining ring; a first spring is arranged on the outer periphery of the conductor to press the conductor downward so that its lower end passes through the lower port of the placement groove.

8. The bearing head according to claim 7, characterized in that, The conductors are multiple and are spaced apart circumferentially along the holding ring; the multiple conductors are distributed at equal intervals so that the current formed by the conductive circuit is uniformly distributed at the edge of the wafer.

9. The bearing head according to claim 7, characterized in that, The bottom surface of the retaining ring is provided with a liquid inlet tank to transfer the polishing slurry for electrochemical mechanical polishing; the placement tank and the liquid inlet tank are staggered to prevent the installed conductor from affecting the supply of polishing slurry.

10. An electrochemical mechanical polishing apparatus, characterized in that, include: A polishing disc with a polishing pad on its top surface; The carrier head according to any one of claims 1 to 9 is used to load the wafer to be processed; The liquid supply section is used to supply polishing liquid toward the polishing pad; The power supply unit is electrically connected to the carrier head via an adapter assembly, so that the wafer is placed in the conductive circuit formed by the elastic membrane, retaining ring and polishing fluid of the carrier head.

11. The electrochemical mechanical polishing apparatus according to claim 10, characterized in that, The adapter assembly is located at the lower part of the polishing shaft and includes a pair of vertically arranged conductive elements; the conductive elements are connected to the conductive terminals at the top of the bearing head to conduct the conductive circuit.

12. The electrochemical mechanical polishing apparatus according to claim 11, characterized in that, The adapter assembly also includes an elastic loading structure, which is disposed above the conductive element to drive the conductive element to move in the vertical direction, thereby compensating for the positional deviation between the bearing head and the adapter assembly, so that the conductive element always abuts against the surface of the conductive terminal.

13. The electrochemical mechanical polishing apparatus according to claim 12, characterized in that, The elastic loading structure includes a protective sleeve and a second spring. The second spring is sleeved on the outer periphery of the conductive component, and the assembly formed by the second spring and the conductive component is disposed in the protective sleeve.

14. The electrochemical mechanical polishing apparatus according to claim 13, characterized in that, The lower end of the second spring abuts against the locking platform of the conductive component, and its upper end abuts against the top wall of the protective sleeve.

15. The electrochemical mechanical polishing apparatus according to claim 14, characterized in that, The protective sleeve is a cylindrical structure with a hole at one end, and a limiting platform is provided on its inner side. The setting size of the limiting platform matches the setting size of the locking platform.

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