Chemical mechanical polishing equipment, polishing solution detection method, polishing method and medium

Abstract

The invention discloses chemical mechanical polishing equipment, a polishing solution detection method, a polishing method and a medium. The chemical mechanical polishing apparatus includes: a polishing disk; the bearing head is used for polishing the wafer on the polishing disc; the liquid supply assembly is used for supplying polishing liquid to the bearing head, and the polishing liquid is distributed on the polishing surface of the polishing disc; the lifting check ring is arranged on the periphery of the polishing disc, a Helmholtz coil is arranged on the lifting check ring, the lifting check ring is provided with an avoiding position when polishing is stopped and a blocking position when polishing is conducted, and when the lifting check ring is located at the blocking position, the polishing surface of the polishing disc is located within the range of the Helmholtz coil so that a basic magnetic field can be formed on the polishing surface; the pulse generating arm is used for superposing a pulse magnetic field on the polishing liquid; and the magnetic field detection arm is arranged between the pulse generation arm and the bearing head and is used for detecting a nuclear magnetic resonance signal responding to the pulse magnetic field so as to determine the distribution condition of the polishing solution according to relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

Description

Technical Field

[0001] The present application relates to the field of semiconductor processing technology, and in particular to a chemical mechanical polishing device, a polishing liquid detection method, a polishing method, and a medium. Background Art

[0002] In the chemical mechanical polishing (CMP) process, alkaline silica polishing liquid is generally used to achieve efficient removal of surface materials by chemical-mechanical synergy. Specifically, the alkaline environment promotes chemical reactions on the silicon surface to generate soluble silicates, while the negatively charged silica nanoparticles dispersed in the polishing liquid accelerate the detachment of reaction products and the removal of surface damage layers through the dual mechanisms of adsorption effect and mechanical friction.

[0003] The uniformity of the distribution of the polishing liquid on the rotating polishing disk directly affects the concentration of chemically active substances in the contact area with the wafer and the mechanical strength of the abrasive particles, which in turn determines the global planarization effect and the spatial consistency of the material removal rate. Summary of the invention

[0004] In view of this, the present application provides a chemical mechanical polishing device, a polishing liquid detection method, and a polishing method and medium to at least partially solve the above technical problems.

[0005] The first aspect of the present application provides a chemical mechanical polishing device, comprising: a polishing disk; a carrier head for polishing a wafer on the polishing disk; a liquid supply assembly for supplying polishing liquid to the carrier head, the polishing liquid being distributed on the polishing surface of the polishing disk; a lifting retaining ring arranged on the outer periphery of the polishing disk, on which a Helmholtz coil is arranged, the lifting retaining ring having an avoidance position when polishing is stopped and a blocking position when polishing is performed, and when the lifting retaining ring is located at the blocking position, the polishing surface of the polishing disk is located within the range of the Helmholtz coil to form a basic magnetic field on the polishing surface; a pulse generating arm for superimposing a pulse magnetic field on the polishing liquid; a magnetic field detection arm arranged between the pulse generating arm and the carrier head, for detecting a nuclear magnetic resonance signal in response to the pulse magnetic field, so as to determine the distribution of the polishing liquid based on the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

[0006] Optionally, the chemical mechanical polishing equipment further includes: a dressing component for dressing the polishing pad on the polishing disk; the liquid supply component, the dressing component, the pulse generating arm, the magnetic field detection arm, and the carrying head are sequentially distributed in the flow direction of the polishing liquid.

[0007] Optionally, the trimming assembly includes a fixing seat, a swing arm and a trimming assembly 40, and the pulse generating arm reuses the fixing seat of the trimming assembly.

[0008] Optionally, the pulse generating arm includes a cantilever, a central vertical rod, a central pulse coil disposed at the lower end of the central vertical rod, an edge vertical rod, and an edge pulse coil disposed at the lower end of the edge vertical rod.

[0009] Optionally, the cantilever of the pulse generating arm is higher than the swing arm of the trimming assembly. The swing arm of the trimming assembly includes avoidance grooves corresponding to the central vertical rod and the edge vertical rod, so that the central pulse coil and the edge pulse coil are close to the upper surface of the polishing pad.

[0010] Optionally, the pulse generating arm includes a cantilever, a central vertical rod, a central pulse coil disposed at the lower end of the central vertical rod, an edge vertical rod, and an edge pulse coil disposed at the lower end of the edge vertical rod.

[0011] Optionally, the magnetic field detecting arm includes a vertical column, a swing arm, and a detecting coil disposed on the side of the swing arm away from the vertical column; the swing arm is used to drive the detecting coil to swing above the polishing pad and form a motion coupling with the carrier head to determine the distribution of the polishing liquid corresponding to the swing trajectory.

[0012] A second aspect of the present application provides a method for detecting a polishing liquid, which is applied to a chemical mechanical polishing apparatus, including: during the polishing process, making the lifting retaining ring in the blocking position, and the polishing surface of the polishing pad is within the range of the Helmholtz coil on the lifting retaining ring to form a basic magnetic field on the polishing surface; superimposing a pulsed magnetic field on the polishing liquid through the pulse generating arm; detecting the nuclear magnetic resonance signal in response to the pulsed magnetic field through the magnetic field detecting arm disposed between the pulse generating arm and the carrier head; determining the distribution of the polishing liquid according to the relaxation time data of the hydrogen atoms reflected by the nuclear magnetic resonance signal.

[0013] A third aspect of the present application provides a chemical mechanical polishing method, which is applied to a chemical mechanical polishing apparatus, including: during the polishing process, making the lifting retaining ring in the blocking position, and the polishing surface of the polishing pad is within the range of the Helmholtz coil on the lifting retaining ring to form a basic magnetic field on the polishing surface; superimposing a pulsed magnetic field on the polishing liquid through the pulse generating arm; detecting the nuclear magnetic resonance signal in response to the pulsed magnetic field through the magnetic field detecting arm disposed between the pulse generating arm and the carrier head; determining the distribution of the polishing liquid according to the relaxation time data of the hydrogen atoms reflected by the nuclear magnetic resonance signal; controlling the process of supplying the polishing liquid by the liquid supply assembly according to the distribution of the polishing liquid, and / or controlling the carrier head to polish the wafer on the polishing pad.

[0014] A fourth aspect of the present application provides a computer storage medium, on which a computer program is stored, and when the program is executed by a processor, the above method is implemented.

[0015] The fifth aspect of the present application provides a computer program product, including computer instructions, which direct a computing device to perform operations corresponding to the above methods.

[0016] The beneficial effects of this patented technology are mainly reflected in the following aspects: In terms of polishing liquid distribution detection, through components such as Helmholtz coils, pulse generating arms, and magnetic field detection arms, it is possible to determine the distribution of the polishing liquid in real time during the polishing process, solving the problem that existing CMP equipment generally lacks the ability to monitor the dynamic distribution state of the polishing liquid in real time, enabling operators to promptly understand the state of the polishing liquid. By using the relaxation time data of hydrogen atoms reflected by nuclear magnetic resonance signals, the accumulation degree of various particles in the polishing liquid can be accurately evaluated, and then the distribution of the polishing liquid can be inferred, providing an accurate basis for optimizing the polishing process and helping to improve the polishing quality and consistency.

[0017] In addition, this technology can not only detect the distribution of the polishing liquid, but also analyze the dynamic behavior of the polishing liquid, such as the breaking of abrasive particles, the failure of oxidation components, and the gelation of the polishing liquid, based on the decomposition of nuclear magnetic resonance signals, and give an alarm or prompt in a timely manner so as to take corresponding measures to further optimize the polishing process.

[0018] In terms of equipment structure and cost, this technology realizes the function of detecting the distribution of the polishing liquid without major modifications to the polishing unit, does not increase the overall volume of the polishing unit, saves space, and is convenient for modification and upgrade on existing equipment. At the same time, the pulse generating arm reuses the fixed seat of the dressing component, reducing the number of components and costs, lowering the implementation difficulty, while providing a high degree of motion redundancy and improving the economy and practicality of the equipment.

[0019] In terms of temperature compensation, this technology establishes a temperature compensation mechanism. By obtaining the temperature distribution data of the polishing platen in real time and compensating the nuclear magnetic resonance signals based on the temperature compensation coefficient, it effectively suppresses the modulation effect of the relaxation time drift caused by temperature fluctuations on the signal amplitude, improving the accuracy and reliability of detection, and making the detection results more truly reflect the distribution of the polishing liquid. The intrinsic temperature response modeling based on relaxation dynamics has stronger physical interpretability and working condition adaptability compared with the empirical compensation method, can better adapt to different polishing processes and environmental conditions, and enhances the versatility and stability of the equipment. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0021] Figure 1 is a schematic diagram of a chemical mechanical polishing apparatus according to an embodiment of the present application; Figure 2 is a schematic diagram of a chemical mechanical polishing apparatus with an optical measurement device according to an embodiment of the present application; Figure 3 is a flowchart of the steps of a polishing liquid detection method according to an embodiment of the present application; Figure 4 is a schematic diagram of an acquired optical measurement signal; Figure 5 is a schematic diagram of another acquired optical measurement signal; Figure 6 is a schematic diagram of an acquired optical measurement signal and its characterized reflectivity; Figure 7 is a schematic diagram of another acquired optical measurement signal and its characterized reflectivity; Figure 8 is a flowchart of the steps of adjusting the output light intensity according to the reflectivity according to an embodiment of the present application; Figure 9 is a schematic diagram of an acquired optical measurement signal at a sample voltage; Figure 10 is a schematic flowchart of a polishing liquid detection method according to an embodiment of the present application; Figure 11 is a schematic flowchart of a polishing liquid detection method according to an embodiment of the present application; Figure 12 is a schematic diagram of an electronic device according to an embodiment of the present application.

[0022] 10. Carrier head; 20. Polishing disc; 30. Liquid supply component; 40. Dressing component; 50. Pulse generating arm; 501. Cantilever; 502. Central vertical rod; 503. Central pulse coil; 504. Edge pulse coil; 505. Edge vertical rod; 60. Magnetic field detection arm; 601. Base; 602. Swing arm; 603. Column; 604. Detection coil; 605. Shield; 70. Lifting retaining ring; 701. Cylinder; 702. Sealing cover; 703. Lifting retaining ring body; 704. Upper excitation cable; 705. Lower excitation cable; 401. Swing arm shield; 402. Main pulley; 403. First pipeline fixing block; 404. Belt; 405. Second pipeline fixing block; 406. Auxiliary pulley; 407. Second belt follower; 408. Belt tensioner; 409. First belt follower; 800. Electronic device; 801. Processor; 802. Communication interface; 803. Memory; 804. Communication bus; 805. Program. Detailed implementation manners

[0023] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art shall fall within the protection scope of the embodiments of the present application.

[0024] The terms used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "said" and "the" used in the present 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.

[0025] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "when" or "in response to a determination".

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application. Without conflict, the following various embodiments and their technical features can be combined with each other.

[0027] To illustrate the technical solutions described in the present invention, the following will be described with reference to the accompanying drawings and in conjunction with embodiments.

[0028] In the present application, Chemical Mechanical Polishing is also known as Chemical Mechanical Planarization. A wafer is also known as a chip, silicon wafer, substrate, or base plate, etc., and their meanings and actual functions are equivalent.

[0029] As Figures 1-7 shown, the chemical mechanical polishing equipment includes a carrier head 10 for holding the wafer w and driving the wafer w to rotate, a polishing platen 20 covered with a polishing pad, and a liquid supply assembly 30 for supplying polishing liquid.

[0030] During the chemical mechanical polishing process, the carrier head 10 presses the wafer w onto the polishing pad covered on the surface of the polishing platen 20, and the carrier head 10 makes a rotational movement and a reciprocating movement along the radial direction of the polishing platen 20, so that the surface of the wafer w in contact with the polishing pad is gradually removed. At the same time, the polishing platen 20 rotates, and the liquid supply assembly 30 sprays the polishing liquid onto the surface of the polishing pad. Under the chemical action of the polishing liquid, the wafer w and the polishing pad are rubbed through the relative movement of the carrier head 10 and the polishing platen 20 for polishing. During polishing, the dressing assembly 40 is used to dress and activate the surface topography of the polishing pad. Using the dressing assembly 40 can remove impurity particles remaining on the surface of the polishing pad, such as abrasive particles in the polishing liquid and waste materials shed from the surface of the wafer w, etc., and can also planarize the deformation of the surface of the polishing pad caused by grinding.

[0031] Due to the centrifugal effect caused by the high-speed rotation of the polishing platen, the adsorption difference of the porous structure of the polishing pad to the liquid, and the fluctuations of process parameters (pressure, rotation speed), the polishing liquid is prone to local enrichment or depletion phenomena, resulting in uneven material removal rates on the wafer surface, and even inducing the accumulation of residues or micro-scratches. However, existing CMP equipment generally lacks the ability to monitor the dynamic distribution state of the polishing liquid in real time.

[0032] Therefore, this embodiment provides a real-time monitoring solution for the polishing liquid.

[0033] Specifically, a lifting retaining ring 70 is provided on the outer periphery of the polishing pad. The lifting retaining ring has an avoidance position when polishing stops and a blocking position when polishing is in progress. When polishing is not carried out, the lifting retaining ring is in the avoidance position to allow the carrier head to swing into and out of the polishing pad. When polishing is in progress, the lifting retaining ring is in the blocking position to prevent the polishing liquid on the polishing pad from splashing.

[0034] Helmholtz coils are provided on the lifting retaining ring. When the lifting retaining ring is in the blocking position, the polishing surface of the polishing pad is within the range of the Helmholtz coils to form a basic magnetic field on the polishing surface. See Figure 8 , the basic magnetic field can make the hydrogen (H) atoms in the polishing liquid have relatively fixed magnetic moments. The hydrogen atoms move in a spiral around the magnetic field direction B0. At this time, there are two types of hydrogen atoms in the low energy level and the high energy level, and an equilibrium is formed.

[0035] In this embodiment, see Figure 6 , the lifting retaining ring 70 includes a cylinder 701, a sealing cover 702, a lifting retaining ring main body 703, an upper excitation cable 704 and a lower excitation cable 705. The sealing cover 702 provides sealing for the upper excitation cable 704 and the lower excitation cable 705. By energizing the upper excitation cable 704 and the lower excitation cable 705 to form Helmholtz coils, a stable basic magnetic field is formed between them. During the polishing process, the cylinder 701 drives the lifting retaining ring main body 703 to rise, so that the polishing surface on the polishing pad is in the basic magnetic field.

[0036] After the basic magnetic field is generated, the polishing liquid can be detected based on the nuclear magnetic resonance effect. Therefore, the chemical mechanical polishing equipment further includes a pulse generating arm 50 and a magnetic field detecting arm 60 for detection.

[0037] The pulse generating arm is used to superimpose a pulsed magnetic field on the polishing liquid. Specifically, in this embodiment, the pulse generating arm includes a cantilever, a central vertical rod, a central pulse coil provided at the lower end of the central vertical rod, an edge vertical rod, and an edge pulse coil provided at the lower end of the edge vertical rod. By the central pulse coil and the edge pulse coil, a pulsed magnetic field can be applied to the polishing liquid in the annular range corresponding to the carrier head on the polishing pad. As Figure 7 shown, the carrier head reciprocates on the polishing pad, and the annular range can be an annular range covering the swinging area of the carrier head. The direction of the pulsed magnetic field can be B1 as shown in Figure 8 .

[0038] The magnetic field detecting arm is arranged between the pulse generating arm and the carrier head and is used to detect the nuclear magnetic resonance signal in response to the pulsed magnetic field, so as to determine the distribution of the polishing liquid according to the relaxation time data of the hydrogen atoms reflected by the nuclear magnetic resonance signal. Specifically, see Figure 5, the magnetic field detection arm 60 includes a base 601, a swing arm 602, a column 603, a detection coil 604, a shield 605, and a linear module disposed inside the swing arm 602. The swing arm 602 rotates to bring the detection coil 604 above the polishing disc. The shield 605 provides waterproof protection for the detection coil 604. The linear module drives the detection coil 604 to move linearly along the radius of the polishing disc. While forming a motion coupling with the bearing head, the magnetic field intensity at this point is fed back through the current generated by electromagnetic induction, thereby feeding back the distribution of the polishing liquid. Through the cooperation and control of the swing arm 602 and the linear module, the detection range of the detection coil 604 can be maximized, ensuring the coverage range of the detection coil.

[0039] The pulsed magnetic field applied through the pulsed generation arm has a stage of applying the magnetic field and a stage of removing the magnetic field. When the magnetic field is applied, hydrogen atoms with relatively fixed magnetic moments are affected by the pulsed magnetic field, and some hydrogen atoms will absorb energy and jump from the low energy level to the high energy level, changing from the equilibrium state to the non-equilibrium state. The equilibrium state and the non-equilibrium state are as Figure 8 shown; when the magnetic field is removed, the hydrogen atoms will return from the high energy level to the low energy level, returning from the non-equilibrium state to the equilibrium state. This changing time is called the relaxation time.

[0040] The relaxation time is related to the state of water molecules. When water molecules are adsorbed on the surface of particles, such as the surface of chemical molecules in the polishing liquid, the surface of polishing impurities, etc., the relaxation time will be very short. When in a free state, the relaxation time will be relatively long. Assume there are two substances A and B in the polishing liquid, and the size of B is larger than that of A. Then the relaxation time of the water molecules adsorbed on the surface of B is shorter than that of the water molecules adsorbed on the surface of A. When the abrasive grains or contaminants in the polishing liquid accumulate, the proportion of the larger-sized substances in the polishing liquid becomes higher, making the overall relaxation time of the polishing liquid shorter. Thus, the situation of large-sized accumulations in the polishing liquid can be obtained through the relaxation time. See Figure 9 . In the upper and lower curves, the proportion of the large-sized substances D in the lower curve is higher than that of C in the upper curve. Or the relaxation time can be decomposed to obtain the relaxation times corresponding to substances of various sizes and directly obtain the proportions of various types of molecules. In summary, through the above methods, the solid-liquid proportion of water molecules can be evaluated using the relaxation time data, thereby inferring the accumulation degree of various particles in the polishing liquid, that is, the distribution of the polishing liquid.

[0041] In addition to the pulse generating arm and the magnetic field detecting arm, there are also other components distributed above the polishing pad. For example, the chemical mechanical polishing equipment further includes a dressing component 40 for dressing the polishing pad on the polishing disc; the liquid supply component, the dressing component, the pulse generating arm, the magnetic field detecting arm, and the carrier head are sequentially distributed in the flow direction of the polishing liquid. After flowing out of the liquid supply component, the polishing liquid falls on the polishing disc, and the centrifugal force generated by the rotation of the polishing disc causes the polishing liquid to flow along the rotation direction. The dressing component, the pulse generating arm, the magnetic field detecting arm, and the carrier head are sequentially arranged in the flow direction of the polishing liquid. This arrangement enables the magnetic field detecting arm to detect the polishing liquid that is about to flow under the carrier head, and the detection result is more effective.

[0042] Specifically, the dressing component includes a fixed seat, a swing arm, and a dressing component 40. The fixed seat of the dressing component is reused by the pulse generating arm. Thus, a dedicated fixed seat for the pulse generating arm can be omitted, reducing the number of components and costs. In addition, due to the limited space on the surface of the polishing disc, sharing a fixed seat for the pulse generating arm and the dressing component can minimize the space occupied on the polishing disc during their use, reduce the implementation difficulty, and provide a higher motion redundancy.

[0043] Exemplarily, a pulse generating arm 50 is added above the dressing component 40, which includes a cantilever 501, a central vertical rod 502, a central pulse coil 503, an edge pulse coil 504, and an edge vertical rod 505. The cantilever 501 can drive the pulse generating coil to rotate to a specified position on the polishing disc. The central pulse coil 503 and the edge pulse coil 504 pass opposite pulse currents to generate a pulse magnetic field perpendicular to the basic magnetic field within a range of 2 - 14 inches.

[0044] The cantilever 501 of the pulse generating arm 50 is higher than the swing arm of the dressing component 40. The swing arm of the dressing component 40 includes avoidance grooves corresponding to the central vertical rod and the edge vertical rod, so that the central pulse coil and the edge pulse coil are close to the upper surface of the polishing disc.

[0045] The dressing component 40 includes a swing arm shield 401, a main pulley 402, a secondary pulley 406, a belt 404, a first pipeline fixing block 403, a second pipeline fixing block 405, a first belt follower 409, a second belt follower 407, and a belt tensioner 408. Among them, the main pulley 402 provides power for the belt 404, the secondary pulley 406 is the output end, the first belt follower 409 and the second belt follower 407 change the layout of the belt in the dressing component 40 to provide avoidance grooves for the central vertical rod and the edge vertical rod of the pulse generating arm 50, the belt tensioner 408 tightens the belt, and the first pipeline fixing block 403 and the second pipeline fixing block 405 fix other pipelines to prevent frictional interference with the moving belt 404.

[0046] In the solution provided by the embodiments of the present application, the chemical mechanical polishing equipment includes a polishing platen; a carrier head for polishing a wafer on the polishing platen; a liquid supply assembly for supplying polishing liquid to the carrier head, and the polishing liquid is distributed on the polishing surface of the polishing platen; a lifting retaining ring is arranged on the outer periphery of the polishing platen, and a Helmholtz coil is arranged thereon. The lifting retaining ring has an avoidance position when polishing stops and a blocking position when polishing is in progress. When the lifting retaining ring is in the blocking position, the polishing surface of the polishing platen is within the range of the Helmholtz coil, so as to form a basic magnetic field on the polishing surface; a pulse generating arm for superimposing a pulsed magnetic field on the polishing liquid; a magnetic field detecting arm is arranged between the pulse generating arm and the carrier head for detecting the nuclear magnetic resonance signal in response to the pulsed magnetic field, so as to determine the distribution of the polishing liquid according to the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal. Thus, through the Helmholtz coil, the pulse generating arm, the magnetic field detecting arm, etc., without major modifications to the polishing unit, the distribution of the polishing liquid can be determined during the polishing process, the overall volume of the polishing unit will not increase, and the polishing liquid can be detected in real time.

[0047] See Figure 10 , based on the above chemical mechanical polishing equipment, an embodiment of the present invention provides a method for detecting a polishing liquid, including: S101. During the polishing process, make the lifting retaining ring in the blocking position, and the polishing surface of the polishing platen is within the range of the Helmholtz coil on the lifting retaining ring, so as to form a basic magnetic field on the polishing surface.

[0048] S102. Superimpose a pulsed magnetic field on the polishing liquid through the pulse generating arm.

[0049] S103. Through the magnetic field detecting arm arranged between the pulse generating arm and the carrier head, detect the nuclear magnetic resonance signal in response to the pulsed magnetic field.

[0050] S104. Determine the distribution of the polishing liquid according to the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

[0051] The pulsed magnetic field applied by the pulse generating arm has a stage of applying the magnetic field and a stage of removing the magnetic field. When the magnetic field is applied, hydrogen atoms with relatively fixed magnetic moments are affected by the pulsed magnetic field, and some hydrogen atoms will absorb energy and jump from the low energy level to the high energy level, changing from the equilibrium state to the non-equilibrium state; when the magnetic field is removed, the hydrogen atoms will return from the high energy level to the low energy level, returning from the non-equilibrium state to the equilibrium state, and this changing time is called the relaxation time. In this embodiment, the schematic diagram of the pulsed magnetic field generated can be as Figure 8 shown.

[0052] The relaxation time is related to the state of water molecules. When water molecules are adsorbed on the surface of particles, such as the surface of chemical molecules in the polishing liquid, the surface of polishing impurities, etc., the relaxation time will be very short. When in a free state, the relaxation time will be relatively long. When abrasives or pollutants in the polishing liquid accumulate, the proportion of substances with large sizes in the polishing liquid becomes higher, making the overall relaxation time of the polishing liquid shorter. See Figure 9 , in the upper and lower curves, the proportion of large-size substances D in the lower curve is higher than that of curve C above. Therefore, the solid-liquid proportion of water molecules can be evaluated using the relaxation time data, and thus the accumulation degree of various particles in the polishing liquid, that is, the distribution of the polishing liquid, can be inferred.

[0053] Furthermore, by combining the pulse period of the pulsed magnetic field, the nuclear magnetic resonance signal can be analyzed and decomposed to obtain various relaxation time data.

[0054] Specifically, the nuclear magnetic resonance signal s(T) can be regarded as the superposition of multi-exponential decay curves and can be split in two directions: longitudinal (B0) and transverse (B1):

[0055] Among them, T1,i is the longitudinal relaxation time corresponding to the i-th type of molecule, which characterizes the energy exchange rate between the hydrogen nucleus and the surrounding lattice and is affected by chemical environments such as oxidant concentration and solution viscosity. High-concentration oxidants (such as H 2 O 2 ) will accelerate proton exchange and significantly shorten T1.

[0056] T2,j is the transverse relaxation time corresponding to the j-th type of molecule, which characterizes the dephasing speed of the spin-spin interaction of hydrogen atoms and is closely related to the size and surface roughness of abrasive particles. Particle aggregation will enhance the local magnetic field gradient, resulting in a broadened T2 distribution.

[0057] The decomposition of the nuclear magnetic resonance signal can be achieved through non-negative matrix factorization (NMF). The decay curve is disassembled into several basis functions (representing typical relaxation time components). Combining with a constrained optimization algorithm, the amplitudes (Ai, Bj) of each component and their corresponding relaxation times (T 1 , T 2 ) are solved.

[0058] After decomposition, multiple components can be physically mapped. Specifically, the decomposed relaxation time spectrum can be matched with a calibration database and associated with specific substances (such as T 2 = 10 ms corresponding to SiO 2 abrasive, T 2 = 2 ms corresponding to CeO 2 abrasive). Thus, the distribution of various substances in the polishing liquid can be determined based on the nuclear magnetic resonance signal.

[0059] Further, the dynamic behavior of the polishing liquid can be analyzed based on the decomposition of the nuclear magnetic resonance signal, and an alarm can be issued.

[0060] T 2 Main peak shift: If the main peak T 2 value increases with time, it indicates that the abrasive particles are gradually broken due to the action of mechanical shear force. An alarm for the lack of abrasive particles in the polishing liquid needs to be issued, and the liquid supply component is controlled to increase the liquid supply volume to increase the proportion of abrasive particles to maintain the removal rate.

[0061] T 1 / T 2 Ratio anomaly: A sudden decrease in the ratio may indicate that the oxidation component in the polishing liquid has failed. At this time, it can be prompted that the polishing liquid is lacking and the liquid supply component is controlled to increase the liquid supply volume.

[0062] Sudden drop in diffusion coefficient: By applying a gradient pulse magnetic field, measuring the diffusion movement speed of hydrogen atoms in the polishing liquid, and calculating the diffusion coefficient D value, the dispersion degree of the abrasive can be indirectly reflected (aggregated particles will limit molecular diffusion and reduce the D value). When a decrease in the D value is detected, it indicates that the polishing liquid has gelated (severe particle aggregation). The ultrasonic oscillation module can be started to disperse the particles in the polishing liquid to prevent scratches on the wafer due to particle aggregation in the polishing liquid.

[0063] In this embodiment, referring to Figure 11 , it may further include step S100: determining the temperature of the polishing platen, and step S104 includes: S1041 compensating the relaxation time data based on the relationship curve between the temperature and the relaxation time, and determining the distribution of the polishing liquid according to the compensated relaxation time data.

[0064] According to the temperature of the polishing platen measured by the current temperature sensor, the temperature compensation coefficient αT is calculated, and the original nuclear magnetic resonance signal Sr is weighted and compensated according to the temperature compensation coefficient to obtain the compensated nuclear magnetic resonance signal Sc: Sc = Sr * (1 + αT). The temperature compensation coefficient αT can be obtained by controlling the temperature, measuring the relaxation time data of hydrogen atoms at different temperatures, and performing data fitting calculations.

[0065] Due to the significant influence of temperature on relaxation kinetics in the nuclear magnetic resonance detection system, and chemical mechanical polishing removes the wafer surface based on the combined action of chemistry and mechanics, a large amount of heat will be released, which greatly interferes with the above detection system.

[0066] Therefore, a temperature compensation mechanism is established in this application to eliminate the interference of thermal effects on signal acquisition. Specifically, during implementation, the temperature distribution data of the polishing platen is obtained in real time through a temperature sensor, combined with the relaxation time of hydrogen atoms (T 1 / T 2Based on the temperature-dependent characteristics of (), the nuclear magnetic resonance signal is compensated using a quantization model of the temperature compensation coefficient αT. This coefficient characterizes the relative change rate of the relaxation parameter caused by a unit temperature gradient, and its physical essence reflects the co-evolution law of the thermodynamic properties of the medium and the spin-lattice coupling effect.

[0067] The calibration of the compensation coefficient is achieved through a systematic experimental method: a database of the temperature-relaxation time mapping relationship is established on a precision temperature control platform, and the variable-temperature relaxation spectroscopy measurement technique is used to obtain the dynamic response data of the hydrogen atom spin system within the set temperature range. Based on the non-linear characteristics of the relaxation time varying with temperature, the optimal temperature compensation function is solved through multi-physical field coupling modeling and non-linear regression analysis to obtain the compensation coefficient αT. Finally, during actual measurement, the compensation coefficient αT can be substituted into the signal correction algorithm to perform a weighted compensation operation on the original nuclear magnetic resonance signal Sr (Sc = Sr × (1 + αT)) to obtain the compensated nuclear magnetic resonance signal Sc, effectively suppressing the modulation effect of the relaxation time drift caused by temperature fluctuations on the signal amplitude.

[0068] The core of this compensation strategy lies in establishing a transfer function between the temperature variable and the relaxation parameter, and its technical advantages are reflected in two aspects: firstly, dynamic compensation is achieved through in-situ temperature monitoring, avoiding the energy consumption and delay problems of traditional constant temperature control methods; secondly, based on the intrinsic temperature response modeling of relaxation dynamics, it has stronger physical interpretability and working condition adaptability compared with the empirical compensation method.

[0069] The solution provided by this application can determine the distribution of the polishing liquid based on the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal. Thus, through Helmholtz coils, a pulse generating arm, a magnetic field detecting arm, etc., without major modifications to the polishing unit, the distribution of the polishing liquid can be determined during the polishing process, without increasing the overall volume of the polishing unit, and the polishing liquid can be detected in real time.

[0070] Another embodiment of this application also provides a chemical mechanical polishing method, which is applied to a chemical mechanical polishing device and includes: during the polishing process, the lifting retaining ring is placed in the blocking position, and the polishing surface of the polishing platen is within the range of the Helmholtz coils on the lifting retaining ring to form a basic magnetic field on the polishing surface; a pulsed magnetic field is superimposed on the polishing liquid through the pulse generating arm; the magnetic resonance signal in response to the pulsed magnetic field is detected through a magnetic field detecting arm arranged between the pulse generating arm and the carrier head; the distribution of the polishing liquid is determined based on the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal; and the process of supplying the polishing liquid by the liquid supply component and / or the polishing of the wafer by the carrier head on the polishing platen is controlled according to the distribution of the polishing liquid.

[0071] According to the distribution of the polishing liquid, control the process of the liquid supply component supplying the polishing liquid. Specifically, it can be to control the landing point of the polishing liquid supplied by the liquid supply component according to the distribution of the polishing liquid, control the supply flow rate of the polishing liquid, etc.; control the process of the carrier head polishing the wafer on the polishing pad according to the distribution of the polishing liquid. Specifically, it can be to control the pressure of each pressure-dividing area on the carrier head on the wafer, so as to control the removal rate of each position of the wafer in combination with the distribution of the polishing liquid, or control the rotation speed of the carrier head to control the distribution of the polishing liquid under the carrier head.

[0072] For the specific implementation manners of the steps in the chemical mechanical polishing method, reference can be made to the above embodiments, and details are not described herein again.

[0073] In this embodiment, an electronic device 800 is provided, as Figure 12 shown. The electronic device 800 may include: a processor 801, a communication interface 802, a memory 803, and a communication bus 804. Among them: The processor 801, the communication interface 802, and the memory 803 communicate with each other through the communication bus 804.

[0074] The communication interface 802 is used to communicate with other electronic devices or servers.

[0075] The processor 801 is used to execute the program 805, and specifically can execute the relevant steps in the foregoing embodiments of the polishing liquid detection method.

[0076] Specifically, the program 805 may include program codes, and the program codes include computer operation instructions.

[0077] The processor 801 may be a CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or is configured as one or more integrated circuits. One or more processors included in the intelligent device may be of the same type of processor, such as one or more CPUs; or may be of different types of processors, such as one or more CPUs and one or more ASICs.

[0078] The memory 803 is used to store the program 805. The memory 803 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory.

[0079] The program 805 is specifically used to cause the processor 801 to execute the polishing liquid detection method in the foregoing embodiments.

[0080] In this embodiment, a computer-readable storage medium is provided, storing instructions for causing a machine to execute the polishing liquid detection method as described herein. Specifically, a system or device equipped with the storage medium may be provided, on which software program code for implementing the functions of any one of the above embodiments is stored, and the computer (or CPU or MPU) of the system or device is caused to read and execute the program code stored in the storage medium.

[0081] In this case, the program code read from the storage medium itself can implement the functions in the above method embodiments. Therefore, the program code and the storage medium storing the program code constitute a part of this application.

[0082] Embodiments of the storage medium for providing the program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Optionally, the program code can be downloaded from a server computer via a communication network.

[0083] In this embodiment, a computer program product is provided, including computer instructions that direct a computing device to perform the operations corresponding to the above method embodiments.

[0084] It should be noted that, according to the needs of implementation, each component / step described in the embodiments of this application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of this application.

[0085] The method according to the embodiments of this application can be implemented in hardware, firmware, or be implemented as software or computer code that can be stored in a recording medium (such as CD ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or be implemented as computer code originally stored in a remote recording medium or a non-transitory machine-readable medium and to be stored in a local recording medium and downloaded via a network. Thus, the method described herein can be such software processing stored on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes storage components (such as RAM, ROM, flash memory, etc.) that can store or receive software or computer code. When the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0086] Although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on a reading and understanding of this specification and the drawings. The present application includes all such modifications and changes and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-described components, the terms used to describe such components are intended to correspond to any component that performs the specified function of the component (e.g., it is functionally equivalent), unless otherwise indicated, even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary implementations of this specification shown herein.

[0087] That is, the above is only an embodiment of the present application, and thus does not limit the patent scope of the present application. Any equivalent structural or equivalent process transformation made using the content of the specification and drawings of the present application, such as the mutual combination of technical features between various embodiments, or direct or indirect application in other related technical fields, is similarly included within the patent protection scope of the present application.

[0088] In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0089] The above description is given to enable any person skilled in the art to implement and use the present application. In the above description, various details are set forth for purposes of explanation. It should be understood that those of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other embodiments, well-known processes will not be elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the illustrated embodiments, but is consistent with the broadest scope that conforms to the principles and features disclosed in the present application.

[0090] It should be noted that, on the premise of no conflict, the various embodiments described in the present application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solutions obtained after combination should also fall within the protection scope of the present application.

[0091] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art better understand the embodiments of the present application, rather than limiting the scope of the embodiments of the present application. Those skilled in the art can make various improvements and deformations on the basis of the above embodiments, and these improvements or deformations all fall within the protection scope of the present application.

[0092] As described above, it is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the said claims.

Claims

1. A chemical mechanical polishing device, characterized in that: include: Polishing discs; a carrier head, used for polishing the wafer on the polishing plate; A liquid supply assembly, used for supplying polishing liquid to the carrier head, and the polishing liquid is distributed on the polishing surface of the polishing plate; A lifting retaining ring is arranged on the outer periphery of the polishing disc, and a Helmholtz coil is arranged on the lifting retaining ring. The lifting retaining ring has an avoidance position when polishing is stopped and a blocking position when polishing is performed. When the lifting retaining ring is located at the blocking position, the polishing surface of the polishing disc is located within the range of the Helmholtz coil to form a basic magnetic field on the polishing surface; A pulse generating arm, used for superimposing a pulse magnetic field on the polishing liquid; The magnetic field detection arm is arranged between the pulse generating arm and the carrier head, and is used to detect the nuclear magnetic resonance signal in response to the pulse magnetic field, so as to determine the distribution of the polishing liquid according to the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

2. The chemical mechanical polishing equipment according to claim 1, characterized in that: The chemical mechanical polishing equipment also includes: a dressing component for dressing the polishing pad on the polishing disc; the liquid supply component, the dressing component, the pulse generating arm, the magnetic field detection arm, and the carrier head are distributed in sequence in the flow direction of the polishing liquid.

3. The chemical mechanical polishing equipment according to claim 2, characterized in that: The trimming assembly includes a fixing seat, a swing arm and a trimming assembly 40, and the pulse generating arm reuses the fixing seat of the trimming assembly.

4. The chemical mechanical polishing equipment according to claim 3, characterized in that: The pulse generating arm comprises a cantilever, a central pole, a central pulse coil arranged at the lower end of the central pole, an edge pole, and an edge pulse coil arranged at the lower end of the edge pole.

5. The chemical mechanical polishing equipment according to claim 4, characterized in that: The cantilever of the pulse generating arm is higher than the swing arm of the dressing assembly, and the swing arm of the dressing assembly includes an avoidance groove corresponding to the central upright pole and the edge upright pole, so that the central pulse coil and the edge pulse coil are close to the upper surface of the polishing disk.

6. The chemical mechanical polishing equipment according to claim 1, characterized in that: The pulse generating arm comprises a cantilever, a central pole, a central pulse coil arranged at the lower end of the central pole, an edge pole, and an edge pulse coil arranged at the lower end of the edge pole.

7. The chemical mechanical polishing equipment according to claim 1, characterized in that: The magnetic field detection arm includes a column, a swing arm, and a detection coil arranged on the side of the swing arm away from the column; the swing arm is used to drive the detection coil to swing above the polishing disk and form a motion coupling with the carrier head to determine the distribution of the polishing liquid corresponding to the swing trajectory.

8. A polishing liquid detection method, applied to chemical mechanical polishing equipment, characterized in that: include: During the polishing process, the lifting retaining ring is placed in a blocking position, the polishing surface of the polishing disc is located within the range of the Helmholtz coil on the lifting retaining ring, and a basic magnetic field is formed on the polishing surface; A pulse magnetic field is superimposed on the polishing liquid through a pulse generating arm; detecting a nuclear magnetic resonance signal in response to a pulsed magnetic field by means of a magnetic field detection arm disposed between the pulse generating arm and the carrier head; The distribution of the polishing liquid is determined based on the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

9. A chemical mechanical polishing method, applied to a chemical mechanical polishing device, characterized in that: include: During the polishing process, the lifting retaining ring is placed in a blocking position, the polishing surface of the polishing disc is located within the range of the Helmholtz coil on the lifting retaining ring, and a basic magnetic field is formed on the polishing surface; A pulse magnetic field is superimposed on the polishing liquid through a pulse generating arm; detecting a nuclear magnetic resonance signal in response to a pulsed magnetic field by means of a magnetic field detection arm disposed between the pulse generating arm and the carrier head; Determining the distribution of the polishing liquid according to the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal; According to the distribution of the polishing liquid, the process of the liquid supply component supplying the polishing liquid is controlled, and / or the carrier head is controlled to polish the wafer on the polishing plate.

10. A computer storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the method according to claim 8 or 9.

11. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the method according to claim 8 or 9.

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